Funcionando con correo de devesapark

Mail/env.mail

@@ -0,0 +1,6 @@
+MAIL_SERVER= 'smtp.gmail.com'
+MAIL_PORT=587
+MAIL_USERNAME='devesaparkpadel@gmail.com'
+MAIL_PASSWORD='mzgvprepqhlkuxgy'
+MAIL_USE_TLS='True'
+MAIL_USE_SSL='False'

Mail/mailvenv/bin/Activate.ps1

@@ -0,0 +1,241 @@
+<#
+.Synopsis
+Activate a Python virtual environment for the current PowerShell session.
+
+.Description
+Pushes the python executable for a virtual environment to the front of the
+$Env:PATH environment variable and sets the prompt to signify that you are
+in a Python virtual environment. Makes use of the command line switches as
+well as the `pyvenv.cfg` file values present in the virtual environment.
+
+.Parameter VenvDir
+Path to the directory that contains the virtual environment to activate. The
+default value for this is the parent of the directory that the Activate.ps1
+script is located within.
+
+.Parameter Prompt
+The prompt prefix to display when this virtual environment is activated. By
+default, this prompt is the name of the virtual environment folder (VenvDir)
+surrounded by parentheses and followed by a single space (ie. '(.venv) ').
+
+.Example
+Activate.ps1
+Activates the Python virtual environment that contains the Activate.ps1 script.
+
+.Example
+Activate.ps1 -Verbose
+Activates the Python virtual environment that contains the Activate.ps1 script,
+and shows extra information about the activation as it executes.
+
+.Example
+Activate.ps1 -VenvDir C:\Users\MyUser\Common\.venv
+Activates the Python virtual environment located in the specified location.
+
+.Example
+Activate.ps1 -Prompt "MyPython"
+Activates the Python virtual environment that contains the Activate.ps1 script,
+and prefixes the current prompt with the specified string (surrounded in
+parentheses) while the virtual environment is active.
+
+.Notes
+On Windows, it may be required to enable this Activate.ps1 script by setting the
+execution policy for the user. You can do this by issuing the following PowerShell
+command:
+
+PS C:\> Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
+
+For more information on Execution Policies: 
+https://go.microsoft.com/fwlink/?LinkID=135170
+
+#>
+Param(
+    [Parameter(Mandatory = $false)]
+    [String]
+    $VenvDir,
+    [Parameter(Mandatory = $false)]
+    [String]
+    $Prompt
+)
+
+<# Function declarations --------------------------------------------------- #>
+
+<#
+.Synopsis
+Remove all shell session elements added by the Activate script, including the
+addition of the virtual environment's Python executable from the beginning of
+the PATH variable.
+
+.Parameter NonDestructive
+If present, do not remove this function from the global namespace for the
+session.
+
+#>
+function global:deactivate ([switch]$NonDestructive) {
+    # Revert to original values
+
+    # The prior prompt:
+    if (Test-Path -Path Function:_OLD_VIRTUAL_PROMPT) {
+        Copy-Item -Path Function:_OLD_VIRTUAL_PROMPT -Destination Function:prompt
+        Remove-Item -Path Function:_OLD_VIRTUAL_PROMPT
+    }
+
+    # The prior PYTHONHOME:
+    if (Test-Path -Path Env:_OLD_VIRTUAL_PYTHONHOME) {
+        Copy-Item -Path Env:_OLD_VIRTUAL_PYTHONHOME -Destination Env:PYTHONHOME
+        Remove-Item -Path Env:_OLD_VIRTUAL_PYTHONHOME
+    }
+
+    # The prior PATH:
+    if (Test-Path -Path Env:_OLD_VIRTUAL_PATH) {
+        Copy-Item -Path Env:_OLD_VIRTUAL_PATH -Destination Env:PATH
+        Remove-Item -Path Env:_OLD_VIRTUAL_PATH
+    }
+
+    # Just remove the VIRTUAL_ENV altogether:
+    if (Test-Path -Path Env:VIRTUAL_ENV) {
+        Remove-Item -Path env:VIRTUAL_ENV
+    }
+
+    # Just remove the _PYTHON_VENV_PROMPT_PREFIX altogether:
+    if (Get-Variable -Name "_PYTHON_VENV_PROMPT_PREFIX" -ErrorAction SilentlyContinue) {
+        Remove-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Scope Global -Force
+    }
+
+    # Leave deactivate function in the global namespace if requested:
+    if (-not $NonDestructive) {
+        Remove-Item -Path function:deactivate
+    }
+}
+
+<#
+.Description
+Get-PyVenvConfig parses the values from the pyvenv.cfg file located in the
+given folder, and returns them in a map.
+
+For each line in the pyvenv.cfg file, if that line can be parsed into exactly
+two strings separated by `=` (with any amount of whitespace surrounding the =)
+then it is considered a `key = value` line. The left hand string is the key,
+the right hand is the value.
+
+If the value starts with a `'` or a `"` then the first and last character is
+stripped from the value before being captured.
+
+.Parameter ConfigDir
+Path to the directory that contains the `pyvenv.cfg` file.
+#>
+function Get-PyVenvConfig(
+    [String]
+    $ConfigDir
+) {
+    Write-Verbose "Given ConfigDir=$ConfigDir, obtain values in pyvenv.cfg"
+
+    # Ensure the file exists, and issue a warning if it doesn't (but still allow the function to continue).
+    $pyvenvConfigPath = Join-Path -Resolve -Path $ConfigDir -ChildPath 'pyvenv.cfg' -ErrorAction Continue
+
+    # An empty map will be returned if no config file is found.
+    $pyvenvConfig = @{ }
+
+    if ($pyvenvConfigPath) {
+
+        Write-Verbose "File exists, parse `key = value` lines"
+        $pyvenvConfigContent = Get-Content -Path $pyvenvConfigPath
+
+        $pyvenvConfigContent | ForEach-Object {
+            $keyval = $PSItem -split "\s*=\s*", 2
+            if ($keyval[0] -and $keyval[1]) {
+                $val = $keyval[1]
+
+                # Remove extraneous quotations around a string value.
+                if ("'""".Contains($val.Substring(0, 1))) {
+                    $val = $val.Substring(1, $val.Length - 2)
+                }
+
+                $pyvenvConfig[$keyval[0]] = $val
+                Write-Verbose "Adding Key: '$($keyval[0])'='$val'"
+            }
+        }
+    }
+    return $pyvenvConfig
+}
+
+
+<# Begin Activate script --------------------------------------------------- #>
+
+# Determine the containing directory of this script
+$VenvExecPath = Split-Path -Parent $MyInvocation.MyCommand.Definition
+$VenvExecDir = Get-Item -Path $VenvExecPath
+
+Write-Verbose "Activation script is located in path: '$VenvExecPath'"
+Write-Verbose "VenvExecDir Fullname: '$($VenvExecDir.FullName)"
+Write-Verbose "VenvExecDir Name: '$($VenvExecDir.Name)"
+
+# Set values required in priority: CmdLine, ConfigFile, Default
+# First, get the location of the virtual environment, it might not be
+# VenvExecDir if specified on the command line.
+if ($VenvDir) {
+    Write-Verbose "VenvDir given as parameter, using '$VenvDir' to determine values"
+}
+else {
+    Write-Verbose "VenvDir not given as a parameter, using parent directory name as VenvDir."
+    $VenvDir = $VenvExecDir.Parent.FullName.TrimEnd("\\/")
+    Write-Verbose "VenvDir=$VenvDir"
+}
+
+# Next, read the `pyvenv.cfg` file to determine any required value such
+# as `prompt`.
+$pyvenvCfg = Get-PyVenvConfig -ConfigDir $VenvDir
+
+# Next, set the prompt from the command line, or the config file, or
+# just use the name of the virtual environment folder.
+if ($Prompt) {
+    Write-Verbose "Prompt specified as argument, using '$Prompt'"
+}
+else {
+    Write-Verbose "Prompt not specified as argument to script, checking pyvenv.cfg value"
+    if ($pyvenvCfg -and $pyvenvCfg['prompt']) {
+        Write-Verbose "  Setting based on value in pyvenv.cfg='$($pyvenvCfg['prompt'])'"
+        $Prompt = $pyvenvCfg['prompt'];
+    }
+    else {
+        Write-Verbose "  Setting prompt based on parent's directory's name. (Is the directory name passed to venv module when creating the virutal environment)"
+        Write-Verbose "  Got leaf-name of $VenvDir='$(Split-Path -Path $venvDir -Leaf)'"
+        $Prompt = Split-Path -Path $venvDir -Leaf
+    }
+}
+
+Write-Verbose "Prompt = '$Prompt'"
+Write-Verbose "VenvDir='$VenvDir'"
+
+# Deactivate any currently active virtual environment, but leave the
+# deactivate function in place.
+deactivate -nondestructive
+
+# Now set the environment variable VIRTUAL_ENV, used by many tools to determine
+# that there is an activated venv.
+$env:VIRTUAL_ENV = $VenvDir
+
+if (-not $Env:VIRTUAL_ENV_DISABLE_PROMPT) {
+
+    Write-Verbose "Setting prompt to '$Prompt'"
+
+    # Set the prompt to include the env name
+    # Make sure _OLD_VIRTUAL_PROMPT is global
+    function global:_OLD_VIRTUAL_PROMPT { "" }
+    Copy-Item -Path function:prompt -Destination function:_OLD_VIRTUAL_PROMPT
+    New-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Description "Python virtual environment prompt prefix" -Scope Global -Option ReadOnly -Visibility Public -Value $Prompt
+
+    function global:prompt {
+        Write-Host -NoNewline -ForegroundColor Green "($_PYTHON_VENV_PROMPT_PREFIX) "
+        _OLD_VIRTUAL_PROMPT
+    }
+}
+
+# Clear PYTHONHOME
+if (Test-Path -Path Env:PYTHONHOME) {
+    Copy-Item -Path Env:PYTHONHOME -Destination Env:_OLD_VIRTUAL_PYTHONHOME
+    Remove-Item -Path Env:PYTHONHOME
+}
+
+# Add the venv to the PATH
+Copy-Item -Path Env:PATH -Destination Env:_OLD_VIRTUAL_PATH
+$Env:PATH = "$VenvExecDir$([System.IO.Path]::PathSeparator)$Env:PATH"

Mail/mailvenv/bin/activate

@@ -0,0 +1,76 @@
+# This file must be used with "source bin/activate" *from bash*
+# you cannot run it directly
+
+deactivate () {
+    # reset old environment variables
+    if [ -n "${_OLD_VIRTUAL_PATH:-}" ] ; then
+        PATH="${_OLD_VIRTUAL_PATH:-}"
+        export PATH
+        unset _OLD_VIRTUAL_PATH
+    fi
+    if [ -n "${_OLD_VIRTUAL_PYTHONHOME:-}" ] ; then
+        PYTHONHOME="${_OLD_VIRTUAL_PYTHONHOME:-}"
+        export PYTHONHOME
+        unset _OLD_VIRTUAL_PYTHONHOME
+    fi
+
+    # This should detect bash and zsh, which have a hash command that must
+    # be called to get it to forget past commands.  Without forgetting
+    # past commands the $PATH changes we made may not be respected
+    if [ -n "${BASH:-}" -o -n "${ZSH_VERSION:-}" ] ; then
+        hash -r
+    fi
+
+    if [ -n "${_OLD_VIRTUAL_PS1:-}" ] ; then
+        PS1="${_OLD_VIRTUAL_PS1:-}"
+        export PS1
+        unset _OLD_VIRTUAL_PS1
+    fi
+
+    unset VIRTUAL_ENV
+    if [ ! "${1:-}" = "nondestructive" ] ; then
+    # Self destruct!
+        unset -f deactivate
+    fi
+}
+
+# unset irrelevant variables
+deactivate nondestructive
+
+VIRTUAL_ENV="/home/creylopez/AppsPy/Mail/mailvenv"
+export VIRTUAL_ENV
+
+_OLD_VIRTUAL_PATH="$PATH"
+PATH="$VIRTUAL_ENV/bin:$PATH"
+export PATH
+
+# unset PYTHONHOME if set
+# this will fail if PYTHONHOME is set to the empty string (which is bad anyway)
+# could use `if (set -u; : $PYTHONHOME) ;` in bash
+if [ -n "${PYTHONHOME:-}" ] ; then
+    _OLD_VIRTUAL_PYTHONHOME="${PYTHONHOME:-}"
+    unset PYTHONHOME
+fi
+
+if [ -z "${VIRTUAL_ENV_DISABLE_PROMPT:-}" ] ; then
+    _OLD_VIRTUAL_PS1="${PS1:-}"
+    if [ "x(mailvenv) " != x ] ; then
+	PS1="(mailvenv) ${PS1:-}"
+    else
+    if [ "`basename \"$VIRTUAL_ENV\"`" = "__" ] ; then
+        # special case for Aspen magic directories
+        # see https://aspen.io/
+        PS1="[`basename \`dirname \"$VIRTUAL_ENV\"\``] $PS1"
+    else
+        PS1="(`basename \"$VIRTUAL_ENV\"`)$PS1"
+    fi
+    fi
+    export PS1
+fi
+
+# This should detect bash and zsh, which have a hash command that must
+# be called to get it to forget past commands.  Without forgetting
+# past commands the $PATH changes we made may not be respected
+if [ -n "${BASH:-}" -o -n "${ZSH_VERSION:-}" ] ; then
+    hash -r
+fi

Mail/mailvenv/bin/activate.csh

@@ -0,0 +1,37 @@
+# This file must be used with "source bin/activate.csh" *from csh*.
+# You cannot run it directly.
+# Created by Davide Di Blasi <davidedb@gmail.com>.
+# Ported to Python 3.3 venv by Andrew Svetlov <andrew.svetlov@gmail.com>
+
+alias deactivate 'test $?_OLD_VIRTUAL_PATH != 0 && setenv PATH "$_OLD_VIRTUAL_PATH" && unset _OLD_VIRTUAL_PATH; rehash; test $?_OLD_VIRTUAL_PROMPT != 0 && set prompt="$_OLD_VIRTUAL_PROMPT" && unset _OLD_VIRTUAL_PROMPT; unsetenv VIRTUAL_ENV; test "\!:*" != "nondestructive" && unalias deactivate'
+
+# Unset irrelevant variables.
+deactivate nondestructive
+
+setenv VIRTUAL_ENV "/home/creylopez/AppsPy/Mail/mailvenv"
+
+set _OLD_VIRTUAL_PATH="$PATH"
+setenv PATH "$VIRTUAL_ENV/bin:$PATH"
+
+
+set _OLD_VIRTUAL_PROMPT="$prompt"
+
+if (! "$?VIRTUAL_ENV_DISABLE_PROMPT") then
+    if ("mailvenv" != "") then
+        set env_name = "mailvenv"
+    else
+        if (`basename "VIRTUAL_ENV"` == "__") then
+            # special case for Aspen magic directories
+            # see https://aspen.io/
+            set env_name = `basename \`dirname "$VIRTUAL_ENV"\``
+        else
+            set env_name = `basename "$VIRTUAL_ENV"`
+        endif
+    endif
+    set prompt = "[$env_name] $prompt"
+    unset env_name
+endif
+
+alias pydoc python -m pydoc
+
+rehash

Mail/mailvenv/bin/activate.fish

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+# This file must be used with ". bin/activate.fish" *from fish* (http://fishshell.org)
+# you cannot run it directly
+
+function deactivate  -d "Exit virtualenv and return to normal shell environment"
+    # reset old environment variables
+    if test -n "$_OLD_VIRTUAL_PATH"
+        set -gx PATH $_OLD_VIRTUAL_PATH
+        set -e _OLD_VIRTUAL_PATH
+    end
+    if test -n "$_OLD_VIRTUAL_PYTHONHOME"
+        set -gx PYTHONHOME $_OLD_VIRTUAL_PYTHONHOME
+        set -e _OLD_VIRTUAL_PYTHONHOME
+    end
+
+    if test -n "$_OLD_FISH_PROMPT_OVERRIDE"
+        functions -e fish_prompt
+        set -e _OLD_FISH_PROMPT_OVERRIDE
+        functions -c _old_fish_prompt fish_prompt
+        functions -e _old_fish_prompt
+    end
+
+    set -e VIRTUAL_ENV
+    if test "$argv[1]" != "nondestructive"
+        # Self destruct!
+        functions -e deactivate
+    end
+end
+
+# unset irrelevant variables
+deactivate nondestructive
+
+set -gx VIRTUAL_ENV "/home/creylopez/AppsPy/Mail/mailvenv"
+
+set -gx _OLD_VIRTUAL_PATH $PATH
+set -gx PATH "$VIRTUAL_ENV/bin" $PATH
+
+# unset PYTHONHOME if set
+if set -q PYTHONHOME
+    set -gx _OLD_VIRTUAL_PYTHONHOME $PYTHONHOME
+    set -e PYTHONHOME
+end
+
+if test -z "$VIRTUAL_ENV_DISABLE_PROMPT"
+    # fish uses a function instead of an env var to generate the prompt.
+
+    # save the current fish_prompt function as the function _old_fish_prompt
+    functions -c fish_prompt _old_fish_prompt
+
+    # with the original prompt function renamed, we can override with our own.
+    function fish_prompt
+        # Save the return status of the last command
+        set -l old_status $status
+
+        # Prompt override?
+        if test -n "(mailvenv) "
+            printf "%s%s" "(mailvenv) " (set_color normal)
+        else
+            # ...Otherwise, prepend env
+            set -l _checkbase (basename "$VIRTUAL_ENV")
+            if test $_checkbase = "__"
+                # special case for Aspen magic directories
+                # see https://aspen.io/
+                printf "%s[%s]%s " (set_color -b blue white) (basename (dirname "$VIRTUAL_ENV")) (set_color normal)
+            else
+                printf "%s(%s)%s" (set_color -b blue white) (basename "$VIRTUAL_ENV") (set_color normal)
+            end
+        end
+
+        # Restore the return status of the previous command.
+        echo "exit $old_status" | .
+        _old_fish_prompt
+    end
+
+    set -gx _OLD_FISH_PROMPT_OVERRIDE "$VIRTUAL_ENV"
+end

Mail/mailvenv/bin/easy_install

@@ -0,0 +1,8 @@
+#!/home/creylopez/AppsPy/Mail/mailvenv/bin/python3
+# -*- coding: utf-8 -*-
+import re
+import sys
+from setuptools.command.easy_install import main
+if __name__ == '__main__':
+    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
+    sys.exit(main())

Mail/mailvenv/bin/easy_install-3.8

@@ -0,0 +1,8 @@
+#!/home/creylopez/AppsPy/Mail/mailvenv/bin/python3
+# -*- coding: utf-8 -*-
+import re
+import sys
+from setuptools.command.easy_install import main
+if __name__ == '__main__':
+    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
+    sys.exit(main())

Mail/mailvenv/bin/pip

@@ -0,0 +1,8 @@
+#!/home/creylopez/AppsPy/Mail/mailvenv/bin/python3
+# -*- coding: utf-8 -*-
+import re
+import sys
+from pip._internal.cli.main import main
+if __name__ == '__main__':
+    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
+    sys.exit(main())

Mail/mailvenv/bin/pip3

@@ -0,0 +1,8 @@
+#!/home/creylopez/AppsPy/Mail/mailvenv/bin/python3
+# -*- coding: utf-8 -*-
+import re
+import sys
+from pip._internal.cli.main import main
+if __name__ == '__main__':
+    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
+    sys.exit(main())

Mail/mailvenv/bin/pip3.8

@@ -0,0 +1,8 @@
+#!/home/creylopez/AppsPy/Mail/mailvenv/bin/python3
+# -*- coding: utf-8 -*-
+import re
+import sys
+from pip._internal.cli.main import main
+if __name__ == '__main__':
+    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
+    sys.exit(main())

Mail/mailvenv/bin/python

@@ -0,0 +1 @@
+python3

Mail/mailvenv/bin/python3

@@ -0,0 +1 @@
+/usr/bin/python3

Mail/mailvenv/lib/python3.8/site-packages/easy_install.py

@@ -0,0 +1,5 @@
+"""Run the EasyInstall command"""
+
+if __name__ == '__main__':
+    from setuptools.command.easy_install import main
+    main()

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/INSTALLER

@@ -0,0 +1 @@
+pip

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/LICENSE.txt

@@ -0,0 +1,20 @@
+Copyright (c) 2008-2019 The pip developers (see AUTHORS.txt file)
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/METADATA

@@ -0,0 +1,84 @@
+Metadata-Version: 2.1
+Name: pip
+Version: 20.0.2
+Summary: The PyPA recommended tool for installing Python packages.
+Home-page: https://pip.pypa.io/
+Author: The pip developers
+Author-email: pypa-dev@groups.google.com
+License: MIT
+Project-URL: Documentation, https://pip.pypa.io
+Project-URL: Source, https://github.com/pypa/pip
+Keywords: distutils easy_install egg setuptools wheel virtualenv
+Platform: UNKNOWN
+Classifier: Development Status :: 5 - Production/Stable
+Classifier: Intended Audience :: Developers
+Classifier: License :: OSI Approved :: MIT License
+Classifier: Topic :: Software Development :: Build Tools
+Classifier: Programming Language :: Python
+Classifier: Programming Language :: Python :: 2
+Classifier: Programming Language :: Python :: 2.7
+Classifier: Programming Language :: Python :: 3
+Classifier: Programming Language :: Python :: 3.5
+Classifier: Programming Language :: Python :: 3.6
+Classifier: Programming Language :: Python :: 3.7
+Classifier: Programming Language :: Python :: 3.8
+Classifier: Programming Language :: Python :: Implementation :: CPython
+Classifier: Programming Language :: Python :: Implementation :: PyPy
+Requires-Python: >=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*
+
+pip - The Python Package Installer
+==================================
+
+.. image:: https://img.shields.io/pypi/v/pip.svg
+   :target: https://pypi.org/project/pip/
+
+.. image:: https://readthedocs.org/projects/pip/badge/?version=latest
+   :target: https://pip.pypa.io/en/latest
+
+pip is the `package installer`_ for Python. You can use pip to install packages from the `Python Package Index`_ and other indexes.
+
+Please take a look at our documentation for how to install and use pip:
+
+* `Installation`_
+* `Usage`_
+
+Updates are released regularly, with a new version every 3 months. More details can be found in our documentation:
+
+* `Release notes`_
+* `Release process`_
+
+If you find bugs, need help, or want to talk to the developers please use our mailing lists or chat rooms:
+
+* `Issue tracking`_
+* `Discourse channel`_
+* `User IRC`_
+
+If you want to get involved head over to GitHub to get the source code, look at our development documentation and feel free to jump on the developer mailing lists and chat rooms:
+
+* `GitHub page`_
+* `Dev documentation`_
+* `Dev mailing list`_
+* `Dev IRC`_
+
+Code of Conduct
+---------------
+
+Everyone interacting in the pip project's codebases, issue trackers, chat
+rooms, and mailing lists is expected to follow the `PyPA Code of Conduct`_.
+
+.. _package installer: https://packaging.python.org/guides/tool-recommendations/
+.. _Python Package Index: https://pypi.org
+.. _Installation: https://pip.pypa.io/en/stable/installing.html
+.. _Usage: https://pip.pypa.io/en/stable/
+.. _Release notes: https://pip.pypa.io/en/stable/news.html
+.. _Release process: https://pip.pypa.io/en/latest/development/release-process/
+.. _GitHub page: https://github.com/pypa/pip
+.. _Dev documentation: https://pip.pypa.io/en/latest/development
+.. _Issue tracking: https://github.com/pypa/pip/issues
+.. _Discourse channel: https://discuss.python.org/c/packaging
+.. _Dev mailing list: https://groups.google.com/forum/#!forum/pypa-dev
+.. _User IRC: https://webchat.freenode.net/?channels=%23pypa
+.. _Dev IRC: https://webchat.freenode.net/?channels=%23pypa-dev
+.. _PyPA Code of Conduct: https://www.pypa.io/en/latest/code-of-conduct/
+
+

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/RECORD

@@ -0,0 +1,246 @@
+../../../bin/pip,sha256=gWYIKbMNdtZX0AXpoXr-wJpZ_UKnStEDTsZlA2WKq_Y,253
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+pip/_internal/utils/logging.py,sha256=aJL7NldPhS5KGFof6Qt3o3MG5cjm5TOoo7bGRu9_wsg,13033
+pip/_internal/utils/marker_files.py,sha256=CO5djQlrPIozJpJybViH_insoAaBGY1aqEt6-cC-iW0,741
+pip/_internal/utils/misc.py,sha256=uIb58Hiu_g2HRORo2aMcgnW_7R5d-5wUAuoW0fA2ZME,26085
+pip/_internal/utils/models.py,sha256=IA0hw_T4awQzui0kqfIEASm5yLtgZAB08ag59Nip5G8,1148
+pip/_internal/utils/packaging.py,sha256=VtiwcAAL7LBi7tGL2je7LeW4bE11KMHGCsJ1NZY5XtM,3035
+pip/_internal/utils/pkg_resources.py,sha256=ZX-k7V5q_aNWyDse92nN7orN1aCpRLsaxzpkBZ1XKzU,1254
+pip/_internal/utils/setuptools_build.py,sha256=DouaVolV9olDDFIIN9IszaL-FHdNaZt10ufOZFH9ZAU,5070
+pip/_internal/utils/subprocess.py,sha256=Ph3x5eHQBxFotyGhpZN8asSMBud-BBkmgaNfARG-di8,9922
+pip/_internal/utils/temp_dir.py,sha256=87Ib8aNic_hoSDEmUYJHTQIn5-prL2AYL5u_yZ3s4sI,7768
+pip/_internal/utils/typing.py,sha256=xkYwOeHlf4zsHXBDC4310HtEqwhQcYXFPq2h35Tcrl0,1401
+pip/_internal/utils/ui.py,sha256=0FNxXlGtbpPtTviv2oXS9t8bQG_NBdfUgP4GbubhS9U,13911
+pip/_internal/utils/unpacking.py,sha256=M944JTSiapBOSKLWu7lbawpVHSE7flfzZTEr3TAG7v8,9438
+pip/_internal/utils/urls.py,sha256=aNV9wq5ClUmrz6sG-al7hEWJ4ToitOy7l82CmFGFNW8,1481
+pip/_internal/utils/virtualenv.py,sha256=Q3S1WPlI7JWpGOT2jUVJ8l2chm_k7VPJ9cHA_cUluEU,3396
+pip/_internal/utils/wheel.py,sha256=grTRwZtMQwApwbbSPmRVLtac6FKy6SVKeCXNkWyyePA,7302
+pip/_internal/vcs/__init__.py,sha256=viJxJRqRE_mVScum85bgQIXAd6o0ozFt18VpC-qIJrM,617
+pip/_internal/vcs/__pycache__/__init__.cpython-38.pyc,,
+pip/_internal/vcs/__pycache__/bazaar.cpython-38.pyc,,
+pip/_internal/vcs/__pycache__/git.cpython-38.pyc,,
+pip/_internal/vcs/__pycache__/mercurial.cpython-38.pyc,,
+pip/_internal/vcs/__pycache__/subversion.cpython-38.pyc,,
+pip/_internal/vcs/__pycache__/versioncontrol.cpython-38.pyc,,
+pip/_internal/vcs/bazaar.py,sha256=84q1-kj1_nJ9AMzMu8RmMp-riRZu81M7K9kowcYgi3U,3957
+pip/_internal/vcs/git.py,sha256=CdLz3DTsZsLMLPZpEuUwiS40npvDaVB1CNRzoXgcuJQ,14352
+pip/_internal/vcs/mercurial.py,sha256=2mg7BdYI_Fe00fF6omaNccFQLPHBsDBG5CAEzvqn5sA,5110
+pip/_internal/vcs/subversion.py,sha256=Fpwy71AmuqXnoKi6h1SrXRtPjEMn8fieuM1O4j01IBg,12292
+pip/_internal/vcs/versioncontrol.py,sha256=nqoaM1_rzx24WnHtihXA8RcPpnUae0sV2sR_LS_5HFA,22600
+pip/_internal/wheel_builder.py,sha256=gr9jE14W5ZuYblpldo-tpRuyG0e0AVmHLttImuAvXlE,9441
+pip/_vendor/__init__.py,sha256=RcHf8jwLPL0ZEaa6uMhTSfyCrA_TpWgDWAW5br9xD7Y,4975
+pip/_vendor/__pycache__/__init__.cpython-38.pyc,,

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/WHEEL

@@ -0,0 +1,6 @@
+Wheel-Version: 1.0
+Generator: bdist_wheel (0.34.2)
+Root-Is-Purelib: true
+Tag: py2-none-any
+Tag: py3-none-any
+

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/entry_points.txt

@@ -0,0 +1,5 @@
+[console_scripts]
+pip = pip._internal.cli.main:main
+pip3 = pip._internal.cli.main:main
+pip3.8 = pip._internal.cli.main:main
+

Mail/mailvenv/lib/python3.8/site-packages/pip-20.0.2.dist-info/top_level.txt

@@ -0,0 +1 @@
+pip

Mail/mailvenv/lib/python3.8/site-packages/pip/__init__.py

@@ -0,0 +1,18 @@
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional
+
+
+__version__ = "20.0.2"
+
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    """This is an internal API only meant for use by pip's own console scripts.
+
+    For additional details, see https://github.com/pypa/pip/issues/7498.
+    """
+    from pip._internal.utils.entrypoints import _wrapper
+
+    return _wrapper(args)

Mail/mailvenv/lib/python3.8/site-packages/pip/__main__.py

@@ -0,0 +1,19 @@
+from __future__ import absolute_import
+
+import os
+import sys
+
+# If we are running from a wheel, add the wheel to sys.path
+# This allows the usage python pip-*.whl/pip install pip-*.whl
+if __package__ == '':
+    # __file__ is pip-*.whl/pip/__main__.py
+    # first dirname call strips of '/__main__.py', second strips off '/pip'
+    # Resulting path is the name of the wheel itself
+    # Add that to sys.path so we can import pip
+    path = os.path.dirname(os.path.dirname(__file__))
+    sys.path.insert(0, path)
+
+from pip._internal.cli.main import main as _main  # isort:skip # noqa
+
+if __name__ == '__main__':
+    sys.exit(_main())

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/__init__.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+import pip._internal.utils.inject_securetransport  # noqa
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, List
+
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    """This is preserved for old console scripts that may still be referencing
+    it.
+
+    For additional details, see https://github.com/pypa/pip/issues/7498.
+    """
+    from pip._internal.utils.entrypoints import _wrapper
+
+    return _wrapper(args)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/build_env.py

@@ -0,0 +1,221 @@
+"""Build Environment used for isolation during sdist building
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+import logging
+import os
+import sys
+import textwrap
+from collections import OrderedDict
+from distutils.sysconfig import get_python_lib
+from sysconfig import get_paths
+
+from pip._vendor.pkg_resources import Requirement, VersionConflict, WorkingSet
+
+from pip import __file__ as pip_location
+from pip._internal.utils.subprocess import call_subprocess
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import open_spinner
+
+if MYPY_CHECK_RUNNING:
+    from typing import Tuple, Set, Iterable, Optional, List
+    from pip._internal.index.package_finder import PackageFinder
+
+logger = logging.getLogger(__name__)
+
+
+class _Prefix:
+
+    def __init__(self, path):
+        # type: (str) -> None
+        self.path = path
+        self.setup = False
+        self.bin_dir = get_paths(
+            'nt' if os.name == 'nt' else 'posix_prefix',
+            vars={'base': path, 'platbase': path}
+        )['scripts']
+        # Note: prefer distutils' sysconfig to get the
+        # library paths so PyPy is correctly supported.
+        purelib = get_python_lib(plat_specific=False, prefix=path)
+        platlib = get_python_lib(plat_specific=True, prefix=path)
+        if purelib == platlib:
+            self.lib_dirs = [purelib]
+        else:
+            self.lib_dirs = [purelib, platlib]
+
+
+class BuildEnvironment(object):
+    """Creates and manages an isolated environment to install build deps
+    """
+
+    def __init__(self):
+        # type: () -> None
+        self._temp_dir = TempDirectory(kind="build-env")
+
+        self._prefixes = OrderedDict((
+            (name, _Prefix(os.path.join(self._temp_dir.path, name)))
+            for name in ('normal', 'overlay')
+        ))
+
+        self._bin_dirs = []  # type: List[str]
+        self._lib_dirs = []  # type: List[str]
+        for prefix in reversed(list(self._prefixes.values())):
+            self._bin_dirs.append(prefix.bin_dir)
+            self._lib_dirs.extend(prefix.lib_dirs)
+
+        # Customize site to:
+        # - ensure .pth files are honored
+        # - prevent access to system site packages
+        system_sites = {
+            os.path.normcase(site) for site in (
+                get_python_lib(plat_specific=False),
+                get_python_lib(plat_specific=True),
+            )
+        }
+        self._site_dir = os.path.join(self._temp_dir.path, 'site')
+        if not os.path.exists(self._site_dir):
+            os.mkdir(self._site_dir)
+        with open(os.path.join(self._site_dir, 'sitecustomize.py'), 'w') as fp:
+            fp.write(textwrap.dedent(
+                '''
+                import os, site, sys
+
+                # First, drop system-sites related paths.
+                original_sys_path = sys.path[:]
+                known_paths = set()
+                for path in {system_sites!r}:
+                    site.addsitedir(path, known_paths=known_paths)
+                system_paths = set(
+                    os.path.normcase(path)
+                    for path in sys.path[len(original_sys_path):]
+                )
+                original_sys_path = [
+                    path for path in original_sys_path
+                    if os.path.normcase(path) not in system_paths
+                ]
+                sys.path = original_sys_path
+
+                # Second, add lib directories.
+                # ensuring .pth file are processed.
+                for path in {lib_dirs!r}:
+                    assert not path in sys.path
+                    site.addsitedir(path)
+                '''
+            ).format(system_sites=system_sites, lib_dirs=self._lib_dirs))
+
+    def __enter__(self):
+        self._save_env = {
+            name: os.environ.get(name, None)
+            for name in ('PATH', 'PYTHONNOUSERSITE', 'PYTHONPATH')
+        }
+
+        path = self._bin_dirs[:]
+        old_path = self._save_env['PATH']
+        if old_path:
+            path.extend(old_path.split(os.pathsep))
+
+        pythonpath = [self._site_dir]
+
+        os.environ.update({
+            'PATH': os.pathsep.join(path),
+            'PYTHONNOUSERSITE': '1',
+            'PYTHONPATH': os.pathsep.join(pythonpath),
+        })
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        for varname, old_value in self._save_env.items():
+            if old_value is None:
+                os.environ.pop(varname, None)
+            else:
+                os.environ[varname] = old_value
+
+    def cleanup(self):
+        # type: () -> None
+        self._temp_dir.cleanup()
+
+    def check_requirements(self, reqs):
+        # type: (Iterable[str]) -> Tuple[Set[Tuple[str, str]], Set[str]]
+        """Return 2 sets:
+            - conflicting requirements: set of (installed, wanted) reqs tuples
+            - missing requirements: set of reqs
+        """
+        missing = set()
+        conflicting = set()
+        if reqs:
+            ws = WorkingSet(self._lib_dirs)
+            for req in reqs:
+                try:
+                    if ws.find(Requirement.parse(req)) is None:
+                        missing.add(req)
+                except VersionConflict as e:
+                    conflicting.add((str(e.args[0].as_requirement()),
+                                     str(e.args[1])))
+        return conflicting, missing
+
+    def install_requirements(
+        self,
+        finder,  # type: PackageFinder
+        requirements,  # type: Iterable[str]
+        prefix_as_string,  # type: str
+        message  # type: Optional[str]
+    ):
+        # type: (...) -> None
+        prefix = self._prefixes[prefix_as_string]
+        assert not prefix.setup
+        prefix.setup = True
+        if not requirements:
+            return
+        args = [
+            sys.executable, os.path.dirname(pip_location), 'install',
+            '--ignore-installed', '--no-user', '--prefix', prefix.path,
+            '--no-warn-script-location',
+        ]  # type: List[str]
+        if logger.getEffectiveLevel() <= logging.DEBUG:
+            args.append('-v')
+        for format_control in ('no_binary', 'only_binary'):
+            formats = getattr(finder.format_control, format_control)
+            args.extend(('--' + format_control.replace('_', '-'),
+                         ','.join(sorted(formats or {':none:'}))))
+
+        index_urls = finder.index_urls
+        if index_urls:
+            args.extend(['-i', index_urls[0]])
+            for extra_index in index_urls[1:]:
+                args.extend(['--extra-index-url', extra_index])
+        else:
+            args.append('--no-index')
+        for link in finder.find_links:
+            args.extend(['--find-links', link])
+
+        for host in finder.trusted_hosts:
+            args.extend(['--trusted-host', host])
+        if finder.allow_all_prereleases:
+            args.append('--pre')
+        args.append('--')
+        args.extend(requirements)
+        with open_spinner(message) as spinner:
+            call_subprocess(args, spinner=spinner)
+
+
+class NoOpBuildEnvironment(BuildEnvironment):
+    """A no-op drop-in replacement for BuildEnvironment
+    """
+
+    def __init__(self):
+        pass
+
+    def __enter__(self):
+        pass
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        pass
+
+    def cleanup(self):
+        pass
+
+    def install_requirements(self, finder, requirements, prefix, message):
+        raise NotImplementedError()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cache.py

@@ -0,0 +1,329 @@
+"""Cache Management
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import hashlib
+import json
+import logging
+import os
+
+from pip._vendor.packaging.tags import interpreter_name, interpreter_version
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.exceptions import InvalidWheelFilename
+from pip._internal.models.link import Link
+from pip._internal.models.wheel import Wheel
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Set, List, Any, Dict
+
+    from pip._vendor.packaging.tags import Tag
+
+    from pip._internal.models.format_control import FormatControl
+
+logger = logging.getLogger(__name__)
+
+
+def _hash_dict(d):
+    # type: (Dict[str, str]) -> str
+    """Return a stable sha224 of a dictionary."""
+    s = json.dumps(d, sort_keys=True, separators=(",", ":"), ensure_ascii=True)
+    return hashlib.sha224(s.encode("ascii")).hexdigest()
+
+
+class Cache(object):
+    """An abstract class - provides cache directories for data from links
+
+
+        :param cache_dir: The root of the cache.
+        :param format_control: An object of FormatControl class to limit
+            binaries being read from the cache.
+        :param allowed_formats: which formats of files the cache should store.
+            ('binary' and 'source' are the only allowed values)
+    """
+
+    def __init__(self, cache_dir, format_control, allowed_formats):
+        # type: (str, FormatControl, Set[str]) -> None
+        super(Cache, self).__init__()
+        assert not cache_dir or os.path.isabs(cache_dir)
+        self.cache_dir = cache_dir or None
+        self.format_control = format_control
+        self.allowed_formats = allowed_formats
+
+        _valid_formats = {"source", "binary"}
+        assert self.allowed_formats.union(_valid_formats) == _valid_formats
+
+    def _get_cache_path_parts_legacy(self, link):
+        # type: (Link) -> List[str]
+        """Get parts of part that must be os.path.joined with cache_dir
+
+        Legacy cache key (pip < 20) for compatibility with older caches.
+        """
+
+        # We want to generate an url to use as our cache key, we don't want to
+        # just re-use the URL because it might have other items in the fragment
+        # and we don't care about those.
+        key_parts = [link.url_without_fragment]
+        if link.hash_name is not None and link.hash is not None:
+            key_parts.append("=".join([link.hash_name, link.hash]))
+        key_url = "#".join(key_parts)
+
+        # Encode our key url with sha224, we'll use this because it has similar
+        # security properties to sha256, but with a shorter total output (and
+        # thus less secure). However the differences don't make a lot of
+        # difference for our use case here.
+        hashed = hashlib.sha224(key_url.encode()).hexdigest()
+
+        # We want to nest the directories some to prevent having a ton of top
+        # level directories where we might run out of sub directories on some
+        # FS.
+        parts = [hashed[:2], hashed[2:4], hashed[4:6], hashed[6:]]
+
+        return parts
+
+    def _get_cache_path_parts(self, link):
+        # type: (Link) -> List[str]
+        """Get parts of part that must be os.path.joined with cache_dir
+        """
+
+        # We want to generate an url to use as our cache key, we don't want to
+        # just re-use the URL because it might have other items in the fragment
+        # and we don't care about those.
+        key_parts = {"url": link.url_without_fragment}
+        if link.hash_name is not None and link.hash is not None:
+            key_parts[link.hash_name] = link.hash
+        if link.subdirectory_fragment:
+            key_parts["subdirectory"] = link.subdirectory_fragment
+
+        # Include interpreter name, major and minor version in cache key
+        # to cope with ill-behaved sdists that build a different wheel
+        # depending on the python version their setup.py is being run on,
+        # and don't encode the difference in compatibility tags.
+        # https://github.com/pypa/pip/issues/7296
+        key_parts["interpreter_name"] = interpreter_name()
+        key_parts["interpreter_version"] = interpreter_version()
+
+        # Encode our key url with sha224, we'll use this because it has similar
+        # security properties to sha256, but with a shorter total output (and
+        # thus less secure). However the differences don't make a lot of
+        # difference for our use case here.
+        hashed = _hash_dict(key_parts)
+
+        # We want to nest the directories some to prevent having a ton of top
+        # level directories where we might run out of sub directories on some
+        # FS.
+        parts = [hashed[:2], hashed[2:4], hashed[4:6], hashed[6:]]
+
+        return parts
+
+    def _get_candidates(self, link, canonical_package_name):
+        # type: (Link, Optional[str]) -> List[Any]
+        can_not_cache = (
+            not self.cache_dir or
+            not canonical_package_name or
+            not link
+        )
+        if can_not_cache:
+            return []
+
+        formats = self.format_control.get_allowed_formats(
+            canonical_package_name
+        )
+        if not self.allowed_formats.intersection(formats):
+            return []
+
+        candidates = []
+        path = self.get_path_for_link(link)
+        if os.path.isdir(path):
+            for candidate in os.listdir(path):
+                candidates.append((candidate, path))
+        # TODO remove legacy path lookup in pip>=21
+        legacy_path = self.get_path_for_link_legacy(link)
+        if os.path.isdir(legacy_path):
+            for candidate in os.listdir(legacy_path):
+                candidates.append((candidate, legacy_path))
+        return candidates
+
+    def get_path_for_link_legacy(self, link):
+        # type: (Link) -> str
+        raise NotImplementedError()
+
+    def get_path_for_link(self, link):
+        # type: (Link) -> str
+        """Return a directory to store cached items in for link.
+        """
+        raise NotImplementedError()
+
+    def get(
+        self,
+        link,            # type: Link
+        package_name,    # type: Optional[str]
+        supported_tags,  # type: List[Tag]
+    ):
+        # type: (...) -> Link
+        """Returns a link to a cached item if it exists, otherwise returns the
+        passed link.
+        """
+        raise NotImplementedError()
+
+    def cleanup(self):
+        # type: () -> None
+        pass
+
+
+class SimpleWheelCache(Cache):
+    """A cache of wheels for future installs.
+    """
+
+    def __init__(self, cache_dir, format_control):
+        # type: (str, FormatControl) -> None
+        super(SimpleWheelCache, self).__init__(
+            cache_dir, format_control, {"binary"}
+        )
+
+    def get_path_for_link_legacy(self, link):
+        # type: (Link) -> str
+        parts = self._get_cache_path_parts_legacy(link)
+        return os.path.join(self.cache_dir, "wheels", *parts)
+
+    def get_path_for_link(self, link):
+        # type: (Link) -> str
+        """Return a directory to store cached wheels for link
+
+        Because there are M wheels for any one sdist, we provide a directory
+        to cache them in, and then consult that directory when looking up
+        cache hits.
+
+        We only insert things into the cache if they have plausible version
+        numbers, so that we don't contaminate the cache with things that were
+        not unique. E.g. ./package might have dozens of installs done for it
+        and build a version of 0.0...and if we built and cached a wheel, we'd
+        end up using the same wheel even if the source has been edited.
+
+        :param link: The link of the sdist for which this will cache wheels.
+        """
+        parts = self._get_cache_path_parts(link)
+
+        # Store wheels within the root cache_dir
+        return os.path.join(self.cache_dir, "wheels", *parts)
+
+    def get(
+        self,
+        link,            # type: Link
+        package_name,    # type: Optional[str]
+        supported_tags,  # type: List[Tag]
+    ):
+        # type: (...) -> Link
+        candidates = []
+
+        if not package_name:
+            return link
+
+        canonical_package_name = canonicalize_name(package_name)
+        for wheel_name, wheel_dir in self._get_candidates(
+            link, canonical_package_name
+        ):
+            try:
+                wheel = Wheel(wheel_name)
+            except InvalidWheelFilename:
+                continue
+            if canonicalize_name(wheel.name) != canonical_package_name:
+                logger.debug(
+                    "Ignoring cached wheel {} for {} as it "
+                    "does not match the expected distribution name {}.".format(
+                        wheel_name, link, package_name
+                    )
+                )
+                continue
+            if not wheel.supported(supported_tags):
+                # Built for a different python/arch/etc
+                continue
+            candidates.append(
+                (
+                    wheel.support_index_min(supported_tags),
+                    wheel_name,
+                    wheel_dir,
+                )
+            )
+
+        if not candidates:
+            return link
+
+        _, wheel_name, wheel_dir = min(candidates)
+        return Link(path_to_url(os.path.join(wheel_dir, wheel_name)))
+
+
+class EphemWheelCache(SimpleWheelCache):
+    """A SimpleWheelCache that creates it's own temporary cache directory
+    """
+
+    def __init__(self, format_control):
+        # type: (FormatControl) -> None
+        self._temp_dir = TempDirectory(kind="ephem-wheel-cache")
+
+        super(EphemWheelCache, self).__init__(
+            self._temp_dir.path, format_control
+        )
+
+    def cleanup(self):
+        # type: () -> None
+        self._temp_dir.cleanup()
+
+
+class WheelCache(Cache):
+    """Wraps EphemWheelCache and SimpleWheelCache into a single Cache
+
+    This Cache allows for gracefully degradation, using the ephem wheel cache
+    when a certain link is not found in the simple wheel cache first.
+    """
+
+    def __init__(self, cache_dir, format_control):
+        # type: (str, FormatControl) -> None
+        super(WheelCache, self).__init__(
+            cache_dir, format_control, {'binary'}
+        )
+        self._wheel_cache = SimpleWheelCache(cache_dir, format_control)
+        self._ephem_cache = EphemWheelCache(format_control)
+
+    def get_path_for_link_legacy(self, link):
+        # type: (Link) -> str
+        return self._wheel_cache.get_path_for_link_legacy(link)
+
+    def get_path_for_link(self, link):
+        # type: (Link) -> str
+        return self._wheel_cache.get_path_for_link(link)
+
+    def get_ephem_path_for_link(self, link):
+        # type: (Link) -> str
+        return self._ephem_cache.get_path_for_link(link)
+
+    def get(
+        self,
+        link,            # type: Link
+        package_name,    # type: Optional[str]
+        supported_tags,  # type: List[Tag]
+    ):
+        # type: (...) -> Link
+        retval = self._wheel_cache.get(
+            link=link,
+            package_name=package_name,
+            supported_tags=supported_tags,
+        )
+        if retval is not link:
+            return retval
+
+        return self._ephem_cache.get(
+            link=link,
+            package_name=package_name,
+            supported_tags=supported_tags,
+        )
+
+    def cleanup(self):
+        # type: () -> None
+        self._wheel_cache.cleanup()
+        self._ephem_cache.cleanup()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/__init__.py

@@ -0,0 +1,4 @@
+"""Subpackage containing all of pip's command line interface related code
+"""
+
+# This file intentionally does not import submodules

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/autocompletion.py

@@ -0,0 +1,164 @@
+"""Logic that powers autocompletion installed by ``pip completion``.
+"""
+
+import optparse
+import os
+import sys
+from itertools import chain
+
+from pip._internal.cli.main_parser import create_main_parser
+from pip._internal.commands import commands_dict, create_command
+from pip._internal.utils.misc import get_installed_distributions
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, Iterable, List, Optional
+
+
+def autocomplete():
+    # type: () -> None
+    """Entry Point for completion of main and subcommand options.
+    """
+    # Don't complete if user hasn't sourced bash_completion file.
+    if 'PIP_AUTO_COMPLETE' not in os.environ:
+        return
+    cwords = os.environ['COMP_WORDS'].split()[1:]
+    cword = int(os.environ['COMP_CWORD'])
+    try:
+        current = cwords[cword - 1]
+    except IndexError:
+        current = ''
+
+    parser = create_main_parser()
+    subcommands = list(commands_dict)
+    options = []
+
+    # subcommand
+    subcommand_name = None  # type: Optional[str]
+    for word in cwords:
+        if word in subcommands:
+            subcommand_name = word
+            break
+    # subcommand options
+    if subcommand_name is not None:
+        # special case: 'help' subcommand has no options
+        if subcommand_name == 'help':
+            sys.exit(1)
+        # special case: list locally installed dists for show and uninstall
+        should_list_installed = (
+            subcommand_name in ['show', 'uninstall'] and
+            not current.startswith('-')
+        )
+        if should_list_installed:
+            installed = []
+            lc = current.lower()
+            for dist in get_installed_distributions(local_only=True):
+                if dist.key.startswith(lc) and dist.key not in cwords[1:]:
+                    installed.append(dist.key)
+            # if there are no dists installed, fall back to option completion
+            if installed:
+                for dist in installed:
+                    print(dist)
+                sys.exit(1)
+
+        subcommand = create_command(subcommand_name)
+
+        for opt in subcommand.parser.option_list_all:
+            if opt.help != optparse.SUPPRESS_HELP:
+                for opt_str in opt._long_opts + opt._short_opts:
+                    options.append((opt_str, opt.nargs))
+
+        # filter out previously specified options from available options
+        prev_opts = [x.split('=')[0] for x in cwords[1:cword - 1]]
+        options = [(x, v) for (x, v) in options if x not in prev_opts]
+        # filter options by current input
+        options = [(k, v) for k, v in options if k.startswith(current)]
+        # get completion type given cwords and available subcommand options
+        completion_type = get_path_completion_type(
+            cwords, cword, subcommand.parser.option_list_all,
+        )
+        # get completion files and directories if ``completion_type`` is
+        # ``<file>``, ``<dir>`` or ``<path>``
+        if completion_type:
+            paths = auto_complete_paths(current, completion_type)
+            options = [(path, 0) for path in paths]
+        for option in options:
+            opt_label = option[0]
+            # append '=' to options which require args
+            if option[1] and option[0][:2] == "--":
+                opt_label += '='
+            print(opt_label)
+    else:
+        # show main parser options only when necessary
+
+        opts = [i.option_list for i in parser.option_groups]
+        opts.append(parser.option_list)
+        flattened_opts = chain.from_iterable(opts)
+        if current.startswith('-'):
+            for opt in flattened_opts:
+                if opt.help != optparse.SUPPRESS_HELP:
+                    subcommands += opt._long_opts + opt._short_opts
+        else:
+            # get completion type given cwords and all available options
+            completion_type = get_path_completion_type(cwords, cword,
+                                                       flattened_opts)
+            if completion_type:
+                subcommands = list(auto_complete_paths(current,
+                                                       completion_type))
+
+        print(' '.join([x for x in subcommands if x.startswith(current)]))
+    sys.exit(1)
+
+
+def get_path_completion_type(cwords, cword, opts):
+    # type: (List[str], int, Iterable[Any]) -> Optional[str]
+    """Get the type of path completion (``file``, ``dir``, ``path`` or None)
+
+    :param cwords: same as the environmental variable ``COMP_WORDS``
+    :param cword: same as the environmental variable ``COMP_CWORD``
+    :param opts: The available options to check
+    :return: path completion type (``file``, ``dir``, ``path`` or None)
+    """
+    if cword < 2 or not cwords[cword - 2].startswith('-'):
+        return None
+    for opt in opts:
+        if opt.help == optparse.SUPPRESS_HELP:
+            continue
+        for o in str(opt).split('/'):
+            if cwords[cword - 2].split('=')[0] == o:
+                if not opt.metavar or any(
+                        x in ('path', 'file', 'dir')
+                        for x in opt.metavar.split('/')):
+                    return opt.metavar
+    return None
+
+
+def auto_complete_paths(current, completion_type):
+    # type: (str, str) -> Iterable[str]
+    """If ``completion_type`` is ``file`` or ``path``, list all regular files
+    and directories starting with ``current``; otherwise only list directories
+    starting with ``current``.
+
+    :param current: The word to be completed
+    :param completion_type: path completion type(`file`, `path` or `dir`)i
+    :return: A generator of regular files and/or directories
+    """
+    directory, filename = os.path.split(current)
+    current_path = os.path.abspath(directory)
+    # Don't complete paths if they can't be accessed
+    if not os.access(current_path, os.R_OK):
+        return
+    filename = os.path.normcase(filename)
+    # list all files that start with ``filename``
+    file_list = (x for x in os.listdir(current_path)
+                 if os.path.normcase(x).startswith(filename))
+    for f in file_list:
+        opt = os.path.join(current_path, f)
+        comp_file = os.path.normcase(os.path.join(directory, f))
+        # complete regular files when there is not ``<dir>`` after option
+        # complete directories when there is ``<file>``, ``<path>`` or
+        # ``<dir>``after option
+        if completion_type != 'dir' and os.path.isfile(opt):
+            yield comp_file
+        elif os.path.isdir(opt):
+            yield os.path.join(comp_file, '')

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/base_command.py

@@ -0,0 +1,226 @@
+"""Base Command class, and related routines"""
+
+from __future__ import absolute_import, print_function
+
+import logging
+import logging.config
+import optparse
+import os
+import platform
+import sys
+import traceback
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.command_context import CommandContextMixIn
+from pip._internal.cli.parser import (
+    ConfigOptionParser,
+    UpdatingDefaultsHelpFormatter,
+)
+from pip._internal.cli.status_codes import (
+    ERROR,
+    PREVIOUS_BUILD_DIR_ERROR,
+    SUCCESS,
+    UNKNOWN_ERROR,
+    VIRTUALENV_NOT_FOUND,
+)
+from pip._internal.exceptions import (
+    BadCommand,
+    CommandError,
+    InstallationError,
+    PreviousBuildDirError,
+    UninstallationError,
+)
+from pip._internal.utils.deprecation import deprecated
+from pip._internal.utils.filesystem import check_path_owner
+from pip._internal.utils.logging import BrokenStdoutLoggingError, setup_logging
+from pip._internal.utils.misc import get_prog, normalize_path
+from pip._internal.utils.temp_dir import global_tempdir_manager
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.virtualenv import running_under_virtualenv
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Tuple, Any
+    from optparse import Values
+
+__all__ = ['Command']
+
+logger = logging.getLogger(__name__)
+
+
+class Command(CommandContextMixIn):
+    usage = None  # type: str
+    ignore_require_venv = False  # type: bool
+
+    def __init__(self, name, summary, isolated=False):
+        # type: (str, str, bool) -> None
+        super(Command, self).__init__()
+        parser_kw = {
+            'usage': self.usage,
+            'prog': '%s %s' % (get_prog(), name),
+            'formatter': UpdatingDefaultsHelpFormatter(),
+            'add_help_option': False,
+            'name': name,
+            'description': self.__doc__,
+            'isolated': isolated,
+        }
+
+        self.name = name
+        self.summary = summary
+        self.parser = ConfigOptionParser(**parser_kw)
+
+        # Commands should add options to this option group
+        optgroup_name = '%s Options' % self.name.capitalize()
+        self.cmd_opts = optparse.OptionGroup(self.parser, optgroup_name)
+
+        # Add the general options
+        gen_opts = cmdoptions.make_option_group(
+            cmdoptions.general_group,
+            self.parser,
+        )
+        self.parser.add_option_group(gen_opts)
+
+    def handle_pip_version_check(self, options):
+        # type: (Values) -> None
+        """
+        This is a no-op so that commands by default do not do the pip version
+        check.
+        """
+        # Make sure we do the pip version check if the index_group options
+        # are present.
+        assert not hasattr(options, 'no_index')
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> Any
+        raise NotImplementedError
+
+    def parse_args(self, args):
+        # type: (List[str]) -> Tuple[Any, Any]
+        # factored out for testability
+        return self.parser.parse_args(args)
+
+    def main(self, args):
+        # type: (List[str]) -> int
+        try:
+            with self.main_context():
+                return self._main(args)
+        finally:
+            logging.shutdown()
+
+    def _main(self, args):
+        # type: (List[str]) -> int
+        # Intentionally set as early as possible so globally-managed temporary
+        # directories are available to the rest of the code.
+        self.enter_context(global_tempdir_manager())
+
+        options, args = self.parse_args(args)
+
+        # Set verbosity so that it can be used elsewhere.
+        self.verbosity = options.verbose - options.quiet
+
+        level_number = setup_logging(
+            verbosity=self.verbosity,
+            no_color=options.no_color,
+            user_log_file=options.log,
+        )
+
+        if (
+            sys.version_info[:2] == (2, 7) and
+            not options.no_python_version_warning
+        ):
+            message = (
+                "A future version of pip will drop support for Python 2.7. "
+                "More details about Python 2 support in pip, can be found at "
+                "https://pip.pypa.io/en/latest/development/release-process/#python-2-support"  # noqa
+            )
+            if platform.python_implementation() == "CPython":
+                message = (
+                    "Python 2.7 reached the end of its life on January "
+                    "1st, 2020. Please upgrade your Python as Python 2.7 "
+                    "is no longer maintained. "
+                ) + message
+            deprecated(message, replacement=None, gone_in=None)
+
+        if options.skip_requirements_regex:
+            deprecated(
+                "--skip-requirements-regex is unsupported and will be removed",
+                replacement=(
+                    "manage requirements/constraints files explicitly, "
+                    "possibly generating them from metadata"
+                ),
+                gone_in="20.1",
+                issue=7297,
+            )
+
+        # TODO: Try to get these passing down from the command?
+        #       without resorting to os.environ to hold these.
+        #       This also affects isolated builds and it should.
+
+        if options.no_input:
+            os.environ['PIP_NO_INPUT'] = '1'
+
+        if options.exists_action:
+            os.environ['PIP_EXISTS_ACTION'] = ' '.join(options.exists_action)
+
+        if options.require_venv and not self.ignore_require_venv:
+            # If a venv is required check if it can really be found
+            if not running_under_virtualenv():
+                logger.critical(
+                    'Could not find an activated virtualenv (required).'
+                )
+                sys.exit(VIRTUALENV_NOT_FOUND)
+
+        if options.cache_dir:
+            options.cache_dir = normalize_path(options.cache_dir)
+            if not check_path_owner(options.cache_dir):
+                logger.warning(
+                    "The directory '%s' or its parent directory is not owned "
+                    "or is not writable by the current user. The cache "
+                    "has been disabled. Check the permissions and owner of "
+                    "that directory. If executing pip with sudo, you may want "
+                    "sudo's -H flag.",
+                    options.cache_dir,
+                )
+                options.cache_dir = None
+
+        try:
+            status = self.run(options, args)
+            # FIXME: all commands should return an exit status
+            # and when it is done, isinstance is not needed anymore
+            if isinstance(status, int):
+                return status
+        except PreviousBuildDirError as exc:
+            logger.critical(str(exc))
+            logger.debug('Exception information:', exc_info=True)
+
+            return PREVIOUS_BUILD_DIR_ERROR
+        except (InstallationError, UninstallationError, BadCommand) as exc:
+            logger.critical(str(exc))
+            logger.debug('Exception information:', exc_info=True)
+
+            return ERROR
+        except CommandError as exc:
+            logger.critical('%s', exc)
+            logger.debug('Exception information:', exc_info=True)
+
+            return ERROR
+        except BrokenStdoutLoggingError:
+            # Bypass our logger and write any remaining messages to stderr
+            # because stdout no longer works.
+            print('ERROR: Pipe to stdout was broken', file=sys.stderr)
+            if level_number <= logging.DEBUG:
+                traceback.print_exc(file=sys.stderr)
+
+            return ERROR
+        except KeyboardInterrupt:
+            logger.critical('Operation cancelled by user')
+            logger.debug('Exception information:', exc_info=True)
+
+            return ERROR
+        except BaseException:
+            logger.critical('Exception:', exc_info=True)
+
+            return UNKNOWN_ERROR
+        finally:
+            self.handle_pip_version_check(options)
+
+        return SUCCESS

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/cmdoptions.py

@@ -0,0 +1,957 @@
+"""
+shared options and groups
+
+The principle here is to define options once, but *not* instantiate them
+globally. One reason being that options with action='append' can carry state
+between parses. pip parses general options twice internally, and shouldn't
+pass on state. To be consistent, all options will follow this design.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+import textwrap
+import warnings
+from distutils.util import strtobool
+from functools import partial
+from optparse import SUPPRESS_HELP, Option, OptionGroup
+from textwrap import dedent
+
+from pip._internal.exceptions import CommandError
+from pip._internal.locations import USER_CACHE_DIR, get_src_prefix
+from pip._internal.models.format_control import FormatControl
+from pip._internal.models.index import PyPI
+from pip._internal.models.target_python import TargetPython
+from pip._internal.utils.hashes import STRONG_HASHES
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import BAR_TYPES
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, Callable, Dict, Optional, Tuple
+    from optparse import OptionParser, Values
+    from pip._internal.cli.parser import ConfigOptionParser
+
+logger = logging.getLogger(__name__)
+
+
+def raise_option_error(parser, option, msg):
+    # type: (OptionParser, Option, str) -> None
+    """
+    Raise an option parsing error using parser.error().
+
+    Args:
+      parser: an OptionParser instance.
+      option: an Option instance.
+      msg: the error text.
+    """
+    msg = '{} error: {}'.format(option, msg)
+    msg = textwrap.fill(' '.join(msg.split()))
+    parser.error(msg)
+
+
+def make_option_group(group, parser):
+    # type: (Dict[str, Any], ConfigOptionParser) -> OptionGroup
+    """
+    Return an OptionGroup object
+    group  -- assumed to be dict with 'name' and 'options' keys
+    parser -- an optparse Parser
+    """
+    option_group = OptionGroup(parser, group['name'])
+    for option in group['options']:
+        option_group.add_option(option())
+    return option_group
+
+
+def check_install_build_global(options, check_options=None):
+    # type: (Values, Optional[Values]) -> None
+    """Disable wheels if per-setup.py call options are set.
+
+    :param options: The OptionParser options to update.
+    :param check_options: The options to check, if not supplied defaults to
+        options.
+    """
+    if check_options is None:
+        check_options = options
+
+    def getname(n):
+        # type: (str) -> Optional[Any]
+        return getattr(check_options, n, None)
+    names = ["build_options", "global_options", "install_options"]
+    if any(map(getname, names)):
+        control = options.format_control
+        control.disallow_binaries()
+        warnings.warn(
+            'Disabling all use of wheels due to the use of --build-option '
+            '/ --global-option / --install-option.', stacklevel=2,
+        )
+
+
+def check_dist_restriction(options, check_target=False):
+    # type: (Values, bool) -> None
+    """Function for determining if custom platform options are allowed.
+
+    :param options: The OptionParser options.
+    :param check_target: Whether or not to check if --target is being used.
+    """
+    dist_restriction_set = any([
+        options.python_version,
+        options.platform,
+        options.abi,
+        options.implementation,
+    ])
+
+    binary_only = FormatControl(set(), {':all:'})
+    sdist_dependencies_allowed = (
+        options.format_control != binary_only and
+        not options.ignore_dependencies
+    )
+
+    # Installations or downloads using dist restrictions must not combine
+    # source distributions and dist-specific wheels, as they are not
+    # guaranteed to be locally compatible.
+    if dist_restriction_set and sdist_dependencies_allowed:
+        raise CommandError(
+            "When restricting platform and interpreter constraints using "
+            "--python-version, --platform, --abi, or --implementation, "
+            "either --no-deps must be set, or --only-binary=:all: must be "
+            "set and --no-binary must not be set (or must be set to "
+            ":none:)."
+        )
+
+    if check_target:
+        if dist_restriction_set and not options.target_dir:
+            raise CommandError(
+                "Can not use any platform or abi specific options unless "
+                "installing via '--target'"
+            )
+
+
+def _path_option_check(option, opt, value):
+    # type: (Option, str, str) -> str
+    return os.path.expanduser(value)
+
+
+class PipOption(Option):
+    TYPES = Option.TYPES + ("path",)
+    TYPE_CHECKER = Option.TYPE_CHECKER.copy()
+    TYPE_CHECKER["path"] = _path_option_check
+
+
+###########
+# options #
+###########
+
+help_ = partial(
+    Option,
+    '-h', '--help',
+    dest='help',
+    action='help',
+    help='Show help.',
+)  # type: Callable[..., Option]
+
+isolated_mode = partial(
+    Option,
+    "--isolated",
+    dest="isolated_mode",
+    action="store_true",
+    default=False,
+    help=(
+        "Run pip in an isolated mode, ignoring environment variables and user "
+        "configuration."
+    ),
+)  # type: Callable[..., Option]
+
+require_virtualenv = partial(
+    Option,
+    # Run only if inside a virtualenv, bail if not.
+    '--require-virtualenv', '--require-venv',
+    dest='require_venv',
+    action='store_true',
+    default=False,
+    help=SUPPRESS_HELP
+)  # type: Callable[..., Option]
+
+verbose = partial(
+    Option,
+    '-v', '--verbose',
+    dest='verbose',
+    action='count',
+    default=0,
+    help='Give more output. Option is additive, and can be used up to 3 times.'
+)  # type: Callable[..., Option]
+
+no_color = partial(
+    Option,
+    '--no-color',
+    dest='no_color',
+    action='store_true',
+    default=False,
+    help="Suppress colored output",
+)  # type: Callable[..., Option]
+
+version = partial(
+    Option,
+    '-V', '--version',
+    dest='version',
+    action='store_true',
+    help='Show version and exit.',
+)  # type: Callable[..., Option]
+
+quiet = partial(
+    Option,
+    '-q', '--quiet',
+    dest='quiet',
+    action='count',
+    default=0,
+    help=(
+        'Give less output. Option is additive, and can be used up to 3'
+        ' times (corresponding to WARNING, ERROR, and CRITICAL logging'
+        ' levels).'
+    ),
+)  # type: Callable[..., Option]
+
+progress_bar = partial(
+    Option,
+    '--progress-bar',
+    dest='progress_bar',
+    type='choice',
+    choices=list(BAR_TYPES.keys()),
+    default='on',
+    help=(
+        'Specify type of progress to be displayed [' +
+        '|'.join(BAR_TYPES.keys()) + '] (default: %default)'
+    ),
+)  # type: Callable[..., Option]
+
+log = partial(
+    PipOption,
+    "--log", "--log-file", "--local-log",
+    dest="log",
+    metavar="path",
+    type="path",
+    help="Path to a verbose appending log."
+)  # type: Callable[..., Option]
+
+no_input = partial(
+    Option,
+    # Don't ask for input
+    '--no-input',
+    dest='no_input',
+    action='store_true',
+    default=False,
+    help=SUPPRESS_HELP
+)  # type: Callable[..., Option]
+
+proxy = partial(
+    Option,
+    '--proxy',
+    dest='proxy',
+    type='str',
+    default='',
+    help="Specify a proxy in the form [user:passwd@]proxy.server:port."
+)  # type: Callable[..., Option]
+
+retries = partial(
+    Option,
+    '--retries',
+    dest='retries',
+    type='int',
+    default=5,
+    help="Maximum number of retries each connection should attempt "
+         "(default %default times).",
+)  # type: Callable[..., Option]
+
+timeout = partial(
+    Option,
+    '--timeout', '--default-timeout',
+    metavar='sec',
+    dest='timeout',
+    type='float',
+    default=15,
+    help='Set the socket timeout (default %default seconds).',
+)  # type: Callable[..., Option]
+
+skip_requirements_regex = partial(
+    Option,
+    # A regex to be used to skip requirements
+    '--skip-requirements-regex',
+    dest='skip_requirements_regex',
+    type='str',
+    default='',
+    help=SUPPRESS_HELP,
+)  # type: Callable[..., Option]
+
+
+def exists_action():
+    # type: () -> Option
+    return Option(
+        # Option when path already exist
+        '--exists-action',
+        dest='exists_action',
+        type='choice',
+        choices=['s', 'i', 'w', 'b', 'a'],
+        default=[],
+        action='append',
+        metavar='action',
+        help="Default action when a path already exists: "
+             "(s)witch, (i)gnore, (w)ipe, (b)ackup, (a)bort.",
+    )
+
+
+cert = partial(
+    PipOption,
+    '--cert',
+    dest='cert',
+    type='path',
+    metavar='path',
+    help="Path to alternate CA bundle.",
+)  # type: Callable[..., Option]
+
+client_cert = partial(
+    PipOption,
+    '--client-cert',
+    dest='client_cert',
+    type='path',
+    default=None,
+    metavar='path',
+    help="Path to SSL client certificate, a single file containing the "
+         "private key and the certificate in PEM format.",
+)  # type: Callable[..., Option]
+
+index_url = partial(
+    Option,
+    '-i', '--index-url', '--pypi-url',
+    dest='index_url',
+    metavar='URL',
+    default=PyPI.simple_url,
+    help="Base URL of the Python Package Index (default %default). "
+         "This should point to a repository compliant with PEP 503 "
+         "(the simple repository API) or a local directory laid out "
+         "in the same format.",
+)  # type: Callable[..., Option]
+
+
+def extra_index_url():
+    # type: () -> Option
+    return Option(
+        '--extra-index-url',
+        dest='extra_index_urls',
+        metavar='URL',
+        action='append',
+        default=[],
+        help="Extra URLs of package indexes to use in addition to "
+             "--index-url. Should follow the same rules as "
+             "--index-url.",
+    )
+
+
+no_index = partial(
+    Option,
+    '--no-index',
+    dest='no_index',
+    action='store_true',
+    default=False,
+    help='Ignore package index (only looking at --find-links URLs instead).',
+)  # type: Callable[..., Option]
+
+
+def find_links():
+    # type: () -> Option
+    return Option(
+        '-f', '--find-links',
+        dest='find_links',
+        action='append',
+        default=[],
+        metavar='url',
+        help="If a url or path to an html file, then parse for links to "
+             "archives. If a local path or file:// url that's a directory, "
+             "then look for archives in the directory listing.",
+    )
+
+
+def trusted_host():
+    # type: () -> Option
+    return Option(
+        "--trusted-host",
+        dest="trusted_hosts",
+        action="append",
+        metavar="HOSTNAME",
+        default=[],
+        help="Mark this host or host:port pair as trusted, even though it "
+             "does not have valid or any HTTPS.",
+    )
+
+
+def constraints():
+    # type: () -> Option
+    return Option(
+        '-c', '--constraint',
+        dest='constraints',
+        action='append',
+        default=[],
+        metavar='file',
+        help='Constrain versions using the given constraints file. '
+        'This option can be used multiple times.'
+    )
+
+
+def requirements():
+    # type: () -> Option
+    return Option(
+        '-r', '--requirement',
+        dest='requirements',
+        action='append',
+        default=[],
+        metavar='file',
+        help='Install from the given requirements file. '
+        'This option can be used multiple times.'
+    )
+
+
+def editable():
+    # type: () -> Option
+    return Option(
+        '-e', '--editable',
+        dest='editables',
+        action='append',
+        default=[],
+        metavar='path/url',
+        help=('Install a project in editable mode (i.e. setuptools '
+              '"develop mode") from a local project path or a VCS url.'),
+    )
+
+
+def _handle_src(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    value = os.path.abspath(value)
+    setattr(parser.values, option.dest, value)
+
+
+src = partial(
+    PipOption,
+    '--src', '--source', '--source-dir', '--source-directory',
+    dest='src_dir',
+    type='path',
+    metavar='dir',
+    default=get_src_prefix(),
+    action='callback',
+    callback=_handle_src,
+    help='Directory to check out editable projects into. '
+    'The default in a virtualenv is "<venv path>/src". '
+    'The default for global installs is "<current dir>/src".'
+)  # type: Callable[..., Option]
+
+
+def _get_format_control(values, option):
+    # type: (Values, Option) -> Any
+    """Get a format_control object."""
+    return getattr(values, option.dest)
+
+
+def _handle_no_binary(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    existing = _get_format_control(parser.values, option)
+    FormatControl.handle_mutual_excludes(
+        value, existing.no_binary, existing.only_binary,
+    )
+
+
+def _handle_only_binary(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    existing = _get_format_control(parser.values, option)
+    FormatControl.handle_mutual_excludes(
+        value, existing.only_binary, existing.no_binary,
+    )
+
+
+def no_binary():
+    # type: () -> Option
+    format_control = FormatControl(set(), set())
+    return Option(
+        "--no-binary", dest="format_control", action="callback",
+        callback=_handle_no_binary, type="str",
+        default=format_control,
+        help="Do not use binary packages. Can be supplied multiple times, and "
+             "each time adds to the existing value. Accepts either :all: to "
+             "disable all binary packages, :none: to empty the set, or one or "
+             "more package names with commas between them (no colons). Note "
+             "that some packages are tricky to compile and may fail to "
+             "install when this option is used on them.",
+    )
+
+
+def only_binary():
+    # type: () -> Option
+    format_control = FormatControl(set(), set())
+    return Option(
+        "--only-binary", dest="format_control", action="callback",
+        callback=_handle_only_binary, type="str",
+        default=format_control,
+        help="Do not use source packages. Can be supplied multiple times, and "
+             "each time adds to the existing value. Accepts either :all: to "
+             "disable all source packages, :none: to empty the set, or one or "
+             "more package names with commas between them. Packages without "
+             "binary distributions will fail to install when this option is "
+             "used on them.",
+    )
+
+
+platform = partial(
+    Option,
+    '--platform',
+    dest='platform',
+    metavar='platform',
+    default=None,
+    help=("Only use wheels compatible with <platform>. "
+          "Defaults to the platform of the running system."),
+)  # type: Callable[..., Option]
+
+
+# This was made a separate function for unit-testing purposes.
+def _convert_python_version(value):
+    # type: (str) -> Tuple[Tuple[int, ...], Optional[str]]
+    """
+    Convert a version string like "3", "37", or "3.7.3" into a tuple of ints.
+
+    :return: A 2-tuple (version_info, error_msg), where `error_msg` is
+        non-None if and only if there was a parsing error.
+    """
+    if not value:
+        # The empty string is the same as not providing a value.
+        return (None, None)
+
+    parts = value.split('.')
+    if len(parts) > 3:
+        return ((), 'at most three version parts are allowed')
+
+    if len(parts) == 1:
+        # Then we are in the case of "3" or "37".
+        value = parts[0]
+        if len(value) > 1:
+            parts = [value[0], value[1:]]
+
+    try:
+        version_info = tuple(int(part) for part in parts)
+    except ValueError:
+        return ((), 'each version part must be an integer')
+
+    return (version_info, None)
+
+
+def _handle_python_version(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """
+    Handle a provided --python-version value.
+    """
+    version_info, error_msg = _convert_python_version(value)
+    if error_msg is not None:
+        msg = (
+            'invalid --python-version value: {!r}: {}'.format(
+                value, error_msg,
+            )
+        )
+        raise_option_error(parser, option=option, msg=msg)
+
+    parser.values.python_version = version_info
+
+
+python_version = partial(
+    Option,
+    '--python-version',
+    dest='python_version',
+    metavar='python_version',
+    action='callback',
+    callback=_handle_python_version, type='str',
+    default=None,
+    help=dedent("""\
+    The Python interpreter version to use for wheel and "Requires-Python"
+    compatibility checks. Defaults to a version derived from the running
+    interpreter. The version can be specified using up to three dot-separated
+    integers (e.g. "3" for 3.0.0, "3.7" for 3.7.0, or "3.7.3"). A major-minor
+    version can also be given as a string without dots (e.g. "37" for 3.7.0).
+    """),
+)  # type: Callable[..., Option]
+
+
+implementation = partial(
+    Option,
+    '--implementation',
+    dest='implementation',
+    metavar='implementation',
+    default=None,
+    help=("Only use wheels compatible with Python "
+          "implementation <implementation>, e.g. 'pp', 'jy', 'cp', "
+          " or 'ip'. If not specified, then the current "
+          "interpreter implementation is used.  Use 'py' to force "
+          "implementation-agnostic wheels."),
+)  # type: Callable[..., Option]
+
+
+abi = partial(
+    Option,
+    '--abi',
+    dest='abi',
+    metavar='abi',
+    default=None,
+    help=("Only use wheels compatible with Python "
+          "abi <abi>, e.g. 'pypy_41'.  If not specified, then the "
+          "current interpreter abi tag is used.  Generally "
+          "you will need to specify --implementation, "
+          "--platform, and --python-version when using "
+          "this option."),
+)  # type: Callable[..., Option]
+
+
+def add_target_python_options(cmd_opts):
+    # type: (OptionGroup) -> None
+    cmd_opts.add_option(platform())
+    cmd_opts.add_option(python_version())
+    cmd_opts.add_option(implementation())
+    cmd_opts.add_option(abi())
+
+
+def make_target_python(options):
+    # type: (Values) -> TargetPython
+    target_python = TargetPython(
+        platform=options.platform,
+        py_version_info=options.python_version,
+        abi=options.abi,
+        implementation=options.implementation,
+    )
+
+    return target_python
+
+
+def prefer_binary():
+    # type: () -> Option
+    return Option(
+        "--prefer-binary",
+        dest="prefer_binary",
+        action="store_true",
+        default=False,
+        help="Prefer older binary packages over newer source packages."
+    )
+
+
+cache_dir = partial(
+    PipOption,
+    "--cache-dir",
+    dest="cache_dir",
+    default=USER_CACHE_DIR,
+    metavar="dir",
+    type='path',
+    help="Store the cache data in <dir>."
+)  # type: Callable[..., Option]
+
+
+def _handle_no_cache_dir(option, opt, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """
+    Process a value provided for the --no-cache-dir option.
+
+    This is an optparse.Option callback for the --no-cache-dir option.
+    """
+    # The value argument will be None if --no-cache-dir is passed via the
+    # command-line, since the option doesn't accept arguments.  However,
+    # the value can be non-None if the option is triggered e.g. by an
+    # environment variable, like PIP_NO_CACHE_DIR=true.
+    if value is not None:
+        # Then parse the string value to get argument error-checking.
+        try:
+            strtobool(value)
+        except ValueError as exc:
+            raise_option_error(parser, option=option, msg=str(exc))
+
+    # Originally, setting PIP_NO_CACHE_DIR to a value that strtobool()
+    # converted to 0 (like "false" or "no") caused cache_dir to be disabled
+    # rather than enabled (logic would say the latter).  Thus, we disable
+    # the cache directory not just on values that parse to True, but (for
+    # backwards compatibility reasons) also on values that parse to False.
+    # In other words, always set it to False if the option is provided in
+    # some (valid) form.
+    parser.values.cache_dir = False
+
+
+no_cache = partial(
+    Option,
+    "--no-cache-dir",
+    dest="cache_dir",
+    action="callback",
+    callback=_handle_no_cache_dir,
+    help="Disable the cache.",
+)  # type: Callable[..., Option]
+
+no_deps = partial(
+    Option,
+    '--no-deps', '--no-dependencies',
+    dest='ignore_dependencies',
+    action='store_true',
+    default=False,
+    help="Don't install package dependencies.",
+)  # type: Callable[..., Option]
+
+
+def _handle_build_dir(option, opt, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    if value:
+        value = os.path.abspath(value)
+    setattr(parser.values, option.dest, value)
+
+
+build_dir = partial(
+    PipOption,
+    '-b', '--build', '--build-dir', '--build-directory',
+    dest='build_dir',
+    type='path',
+    metavar='dir',
+    action='callback',
+    callback=_handle_build_dir,
+    help='Directory to unpack packages into and build in. Note that '
+         'an initial build still takes place in a temporary directory. '
+         'The location of temporary directories can be controlled by setting '
+         'the TMPDIR environment variable (TEMP on Windows) appropriately. '
+         'When passed, build directories are not cleaned in case of failures.'
+)  # type: Callable[..., Option]
+
+ignore_requires_python = partial(
+    Option,
+    '--ignore-requires-python',
+    dest='ignore_requires_python',
+    action='store_true',
+    help='Ignore the Requires-Python information.'
+)  # type: Callable[..., Option]
+
+no_build_isolation = partial(
+    Option,
+    '--no-build-isolation',
+    dest='build_isolation',
+    action='store_false',
+    default=True,
+    help='Disable isolation when building a modern source distribution. '
+         'Build dependencies specified by PEP 518 must be already installed '
+         'if this option is used.'
+)  # type: Callable[..., Option]
+
+
+def _handle_no_use_pep517(option, opt, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """
+    Process a value provided for the --no-use-pep517 option.
+
+    This is an optparse.Option callback for the no_use_pep517 option.
+    """
+    # Since --no-use-pep517 doesn't accept arguments, the value argument
+    # will be None if --no-use-pep517 is passed via the command-line.
+    # However, the value can be non-None if the option is triggered e.g.
+    # by an environment variable, for example "PIP_NO_USE_PEP517=true".
+    if value is not None:
+        msg = """A value was passed for --no-use-pep517,
+        probably using either the PIP_NO_USE_PEP517 environment variable
+        or the "no-use-pep517" config file option. Use an appropriate value
+        of the PIP_USE_PEP517 environment variable or the "use-pep517"
+        config file option instead.
+        """
+        raise_option_error(parser, option=option, msg=msg)
+
+    # Otherwise, --no-use-pep517 was passed via the command-line.
+    parser.values.use_pep517 = False
+
+
+use_pep517 = partial(
+    Option,
+    '--use-pep517',
+    dest='use_pep517',
+    action='store_true',
+    default=None,
+    help='Use PEP 517 for building source distributions '
+         '(use --no-use-pep517 to force legacy behaviour).'
+)  # type: Any
+
+no_use_pep517 = partial(
+    Option,
+    '--no-use-pep517',
+    dest='use_pep517',
+    action='callback',
+    callback=_handle_no_use_pep517,
+    default=None,
+    help=SUPPRESS_HELP
+)  # type: Any
+
+install_options = partial(
+    Option,
+    '--install-option',
+    dest='install_options',
+    action='append',
+    metavar='options',
+    help="Extra arguments to be supplied to the setup.py install "
+         "command (use like --install-option=\"--install-scripts=/usr/local/"
+         "bin\"). Use multiple --install-option options to pass multiple "
+         "options to setup.py install. If you are using an option with a "
+         "directory path, be sure to use absolute path.",
+)  # type: Callable[..., Option]
+
+global_options = partial(
+    Option,
+    '--global-option',
+    dest='global_options',
+    action='append',
+    metavar='options',
+    help="Extra global options to be supplied to the setup.py "
+         "call before the install command.",
+)  # type: Callable[..., Option]
+
+no_clean = partial(
+    Option,
+    '--no-clean',
+    action='store_true',
+    default=False,
+    help="Don't clean up build directories."
+)  # type: Callable[..., Option]
+
+pre = partial(
+    Option,
+    '--pre',
+    action='store_true',
+    default=False,
+    help="Include pre-release and development versions. By default, "
+         "pip only finds stable versions.",
+)  # type: Callable[..., Option]
+
+disable_pip_version_check = partial(
+    Option,
+    "--disable-pip-version-check",
+    dest="disable_pip_version_check",
+    action="store_true",
+    default=True,
+    help="Don't periodically check PyPI to determine whether a new version "
+         "of pip is available for download. Implied with --no-index.",
+)  # type: Callable[..., Option]
+
+
+# Deprecated, Remove later
+always_unzip = partial(
+    Option,
+    '-Z', '--always-unzip',
+    dest='always_unzip',
+    action='store_true',
+    help=SUPPRESS_HELP,
+)  # type: Callable[..., Option]
+
+
+def _handle_merge_hash(option, opt_str, value, parser):
+    # type: (Option, str, str, OptionParser) -> None
+    """Given a value spelled "algo:digest", append the digest to a list
+    pointed to in a dict by the algo name."""
+    if not parser.values.hashes:
+        parser.values.hashes = {}
+    try:
+        algo, digest = value.split(':', 1)
+    except ValueError:
+        parser.error('Arguments to %s must be a hash name '
+                     'followed by a value, like --hash=sha256:abcde...' %
+                     opt_str)
+    if algo not in STRONG_HASHES:
+        parser.error('Allowed hash algorithms for %s are %s.' %
+                     (opt_str, ', '.join(STRONG_HASHES)))
+    parser.values.hashes.setdefault(algo, []).append(digest)
+
+
+hash = partial(
+    Option,
+    '--hash',
+    # Hash values eventually end up in InstallRequirement.hashes due to
+    # __dict__ copying in process_line().
+    dest='hashes',
+    action='callback',
+    callback=_handle_merge_hash,
+    type='string',
+    help="Verify that the package's archive matches this "
+         'hash before installing. Example: --hash=sha256:abcdef...',
+)  # type: Callable[..., Option]
+
+
+require_hashes = partial(
+    Option,
+    '--require-hashes',
+    dest='require_hashes',
+    action='store_true',
+    default=False,
+    help='Require a hash to check each requirement against, for '
+         'repeatable installs. This option is implied when any package in a '
+         'requirements file has a --hash option.',
+)  # type: Callable[..., Option]
+
+
+list_path = partial(
+    PipOption,
+    '--path',
+    dest='path',
+    type='path',
+    action='append',
+    help='Restrict to the specified installation path for listing '
+         'packages (can be used multiple times).'
+)  # type: Callable[..., Option]
+
+
+def check_list_path_option(options):
+    # type: (Values) -> None
+    if options.path and (options.user or options.local):
+        raise CommandError(
+            "Cannot combine '--path' with '--user' or '--local'"
+        )
+
+
+no_python_version_warning = partial(
+    Option,
+    '--no-python-version-warning',
+    dest='no_python_version_warning',
+    action='store_true',
+    default=False,
+    help='Silence deprecation warnings for upcoming unsupported Pythons.',
+)  # type: Callable[..., Option]
+
+
+##########
+# groups #
+##########
+
+general_group = {
+    'name': 'General Options',
+    'options': [
+        help_,
+        isolated_mode,
+        require_virtualenv,
+        verbose,
+        version,
+        quiet,
+        log,
+        no_input,
+        proxy,
+        retries,
+        timeout,
+        skip_requirements_regex,
+        exists_action,
+        trusted_host,
+        cert,
+        client_cert,
+        cache_dir,
+        no_cache,
+        disable_pip_version_check,
+        no_color,
+        no_python_version_warning,
+    ]
+}  # type: Dict[str, Any]
+
+index_group = {
+    'name': 'Package Index Options',
+    'options': [
+        index_url,
+        extra_index_url,
+        no_index,
+        find_links,
+    ]
+}  # type: Dict[str, Any]

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/command_context.py

@@ -0,0 +1,36 @@
+from contextlib import contextmanager
+
+from pip._vendor.contextlib2 import ExitStack
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Iterator, ContextManager, TypeVar
+
+    _T = TypeVar('_T', covariant=True)
+
+
+class CommandContextMixIn(object):
+    def __init__(self):
+        # type: () -> None
+        super(CommandContextMixIn, self).__init__()
+        self._in_main_context = False
+        self._main_context = ExitStack()
+
+    @contextmanager
+    def main_context(self):
+        # type: () -> Iterator[None]
+        assert not self._in_main_context
+
+        self._in_main_context = True
+        try:
+            with self._main_context:
+                yield
+        finally:
+            self._in_main_context = False
+
+    def enter_context(self, context_provider):
+        # type: (ContextManager[_T]) -> _T
+        assert self._in_main_context
+
+        return self._main_context.enter_context(context_provider)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/main.py

@@ -0,0 +1,75 @@
+"""Primary application entrypoint.
+"""
+from __future__ import absolute_import
+
+import locale
+import logging
+import os
+import sys
+
+from pip._internal.cli.autocompletion import autocomplete
+from pip._internal.cli.main_parser import parse_command
+from pip._internal.commands import create_command
+from pip._internal.exceptions import PipError
+from pip._internal.utils import deprecation
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional
+
+logger = logging.getLogger(__name__)
+
+
+# Do not import and use main() directly! Using it directly is actively
+# discouraged by pip's maintainers. The name, location and behavior of
+# this function is subject to change, so calling it directly is not
+# portable across different pip versions.
+
+# In addition, running pip in-process is unsupported and unsafe. This is
+# elaborated in detail at
+# https://pip.pypa.io/en/stable/user_guide/#using-pip-from-your-program.
+# That document also provides suggestions that should work for nearly
+# all users that are considering importing and using main() directly.
+
+# However, we know that certain users will still want to invoke pip
+# in-process. If you understand and accept the implications of using pip
+# in an unsupported manner, the best approach is to use runpy to avoid
+# depending on the exact location of this entry point.
+
+# The following example shows how to use runpy to invoke pip in that
+# case:
+#
+#     sys.argv = ["pip", your, args, here]
+#     runpy.run_module("pip", run_name="__main__")
+#
+# Note that this will exit the process after running, unlike a direct
+# call to main. As it is not safe to do any processing after calling
+# main, this should not be an issue in practice.
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    if args is None:
+        args = sys.argv[1:]
+
+    # Configure our deprecation warnings to be sent through loggers
+    deprecation.install_warning_logger()
+
+    autocomplete()
+
+    try:
+        cmd_name, cmd_args = parse_command(args)
+    except PipError as exc:
+        sys.stderr.write("ERROR: %s" % exc)
+        sys.stderr.write(os.linesep)
+        sys.exit(1)
+
+    # Needed for locale.getpreferredencoding(False) to work
+    # in pip._internal.utils.encoding.auto_decode
+    try:
+        locale.setlocale(locale.LC_ALL, '')
+    except locale.Error as e:
+        # setlocale can apparently crash if locale are uninitialized
+        logger.debug("Ignoring error %s when setting locale", e)
+    command = create_command(cmd_name, isolated=("--isolated" in cmd_args))
+
+    return command.main(cmd_args)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/main_parser.py

@@ -0,0 +1,99 @@
+"""A single place for constructing and exposing the main parser
+"""
+
+import os
+import sys
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.parser import (
+    ConfigOptionParser,
+    UpdatingDefaultsHelpFormatter,
+)
+from pip._internal.commands import commands_dict, get_similar_commands
+from pip._internal.exceptions import CommandError
+from pip._internal.utils.misc import get_pip_version, get_prog
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Tuple, List
+
+
+__all__ = ["create_main_parser", "parse_command"]
+
+
+def create_main_parser():
+    # type: () -> ConfigOptionParser
+    """Creates and returns the main parser for pip's CLI
+    """
+
+    parser_kw = {
+        'usage': '\n%prog <command> [options]',
+        'add_help_option': False,
+        'formatter': UpdatingDefaultsHelpFormatter(),
+        'name': 'global',
+        'prog': get_prog(),
+    }
+
+    parser = ConfigOptionParser(**parser_kw)
+    parser.disable_interspersed_args()
+
+    parser.version = get_pip_version()
+
+    # add the general options
+    gen_opts = cmdoptions.make_option_group(cmdoptions.general_group, parser)
+    parser.add_option_group(gen_opts)
+
+    # so the help formatter knows
+    parser.main = True  # type: ignore
+
+    # create command listing for description
+    description = [''] + [
+        '%-27s %s' % (name, command_info.summary)
+        for name, command_info in commands_dict.items()
+    ]
+    parser.description = '\n'.join(description)
+
+    return parser
+
+
+def parse_command(args):
+    # type: (List[str]) -> Tuple[str, List[str]]
+    parser = create_main_parser()
+
+    # Note: parser calls disable_interspersed_args(), so the result of this
+    # call is to split the initial args into the general options before the
+    # subcommand and everything else.
+    # For example:
+    #  args: ['--timeout=5', 'install', '--user', 'INITools']
+    #  general_options: ['--timeout==5']
+    #  args_else: ['install', '--user', 'INITools']
+    general_options, args_else = parser.parse_args(args)
+
+    # --version
+    if general_options.version:
+        sys.stdout.write(parser.version)  # type: ignore
+        sys.stdout.write(os.linesep)
+        sys.exit()
+
+    # pip || pip help -> print_help()
+    if not args_else or (args_else[0] == 'help' and len(args_else) == 1):
+        parser.print_help()
+        sys.exit()
+
+    # the subcommand name
+    cmd_name = args_else[0]
+
+    if cmd_name not in commands_dict:
+        guess = get_similar_commands(cmd_name)
+
+        msg = ['unknown command "%s"' % cmd_name]
+        if guess:
+            msg.append('maybe you meant "%s"' % guess)
+
+        raise CommandError(' - '.join(msg))
+
+    # all the args without the subcommand
+    cmd_args = args[:]
+    cmd_args.remove(cmd_name)
+
+    return cmd_name, cmd_args

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/parser.py

@@ -0,0 +1,265 @@
+"""Base option parser setup"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import optparse
+import sys
+import textwrap
+from distutils.util import strtobool
+
+from pip._vendor.six import string_types
+
+from pip._internal.cli.status_codes import UNKNOWN_ERROR
+from pip._internal.configuration import Configuration, ConfigurationError
+from pip._internal.utils.compat import get_terminal_size
+
+logger = logging.getLogger(__name__)
+
+
+class PrettyHelpFormatter(optparse.IndentedHelpFormatter):
+    """A prettier/less verbose help formatter for optparse."""
+
+    def __init__(self, *args, **kwargs):
+        # help position must be aligned with __init__.parseopts.description
+        kwargs['max_help_position'] = 30
+        kwargs['indent_increment'] = 1
+        kwargs['width'] = get_terminal_size()[0] - 2
+        optparse.IndentedHelpFormatter.__init__(self, *args, **kwargs)
+
+    def format_option_strings(self, option):
+        return self._format_option_strings(option, ' <%s>', ', ')
+
+    def _format_option_strings(self, option, mvarfmt=' <%s>', optsep=', '):
+        """
+        Return a comma-separated list of option strings and metavars.
+
+        :param option:  tuple of (short opt, long opt), e.g: ('-f', '--format')
+        :param mvarfmt: metavar format string - evaluated as mvarfmt % metavar
+        :param optsep:  separator
+        """
+        opts = []
+
+        if option._short_opts:
+            opts.append(option._short_opts[0])
+        if option._long_opts:
+            opts.append(option._long_opts[0])
+        if len(opts) > 1:
+            opts.insert(1, optsep)
+
+        if option.takes_value():
+            metavar = option.metavar or option.dest.lower()
+            opts.append(mvarfmt % metavar.lower())
+
+        return ''.join(opts)
+
+    def format_heading(self, heading):
+        if heading == 'Options':
+            return ''
+        return heading + ':\n'
+
+    def format_usage(self, usage):
+        """
+        Ensure there is only one newline between usage and the first heading
+        if there is no description.
+        """
+        msg = '\nUsage: %s\n' % self.indent_lines(textwrap.dedent(usage), "  ")
+        return msg
+
+    def format_description(self, description):
+        # leave full control over description to us
+        if description:
+            if hasattr(self.parser, 'main'):
+                label = 'Commands'
+            else:
+                label = 'Description'
+            # some doc strings have initial newlines, some don't
+            description = description.lstrip('\n')
+            # some doc strings have final newlines and spaces, some don't
+            description = description.rstrip()
+            # dedent, then reindent
+            description = self.indent_lines(textwrap.dedent(description), "  ")
+            description = '%s:\n%s\n' % (label, description)
+            return description
+        else:
+            return ''
+
+    def format_epilog(self, epilog):
+        # leave full control over epilog to us
+        if epilog:
+            return epilog
+        else:
+            return ''
+
+    def indent_lines(self, text, indent):
+        new_lines = [indent + line for line in text.split('\n')]
+        return "\n".join(new_lines)
+
+
+class UpdatingDefaultsHelpFormatter(PrettyHelpFormatter):
+    """Custom help formatter for use in ConfigOptionParser.
+
+    This is updates the defaults before expanding them, allowing
+    them to show up correctly in the help listing.
+    """
+
+    def expand_default(self, option):
+        if self.parser is not None:
+            self.parser._update_defaults(self.parser.defaults)
+        return optparse.IndentedHelpFormatter.expand_default(self, option)
+
+
+class CustomOptionParser(optparse.OptionParser):
+
+    def insert_option_group(self, idx, *args, **kwargs):
+        """Insert an OptionGroup at a given position."""
+        group = self.add_option_group(*args, **kwargs)
+
+        self.option_groups.pop()
+        self.option_groups.insert(idx, group)
+
+        return group
+
+    @property
+    def option_list_all(self):
+        """Get a list of all options, including those in option groups."""
+        res = self.option_list[:]
+        for i in self.option_groups:
+            res.extend(i.option_list)
+
+        return res
+
+
+class ConfigOptionParser(CustomOptionParser):
+    """Custom option parser which updates its defaults by checking the
+    configuration files and environmental variables"""
+
+    def __init__(self, *args, **kwargs):
+        self.name = kwargs.pop('name')
+
+        isolated = kwargs.pop("isolated", False)
+        self.config = Configuration(isolated)
+
+        assert self.name
+        optparse.OptionParser.__init__(self, *args, **kwargs)
+
+    def check_default(self, option, key, val):
+        try:
+            return option.check_value(key, val)
+        except optparse.OptionValueError as exc:
+            print("An error occurred during configuration: %s" % exc)
+            sys.exit(3)
+
+    def _get_ordered_configuration_items(self):
+        # Configuration gives keys in an unordered manner. Order them.
+        override_order = ["global", self.name, ":env:"]
+
+        # Pool the options into different groups
+        section_items = {name: [] for name in override_order}
+        for section_key, val in self.config.items():
+            # ignore empty values
+            if not val:
+                logger.debug(
+                    "Ignoring configuration key '%s' as it's value is empty.",
+                    section_key
+                )
+                continue
+
+            section, key = section_key.split(".", 1)
+            if section in override_order:
+                section_items[section].append((key, val))
+
+        # Yield each group in their override order
+        for section in override_order:
+            for key, val in section_items[section]:
+                yield key, val
+
+    def _update_defaults(self, defaults):
+        """Updates the given defaults with values from the config files and
+        the environ. Does a little special handling for certain types of
+        options (lists)."""
+
+        # Accumulate complex default state.
+        self.values = optparse.Values(self.defaults)
+        late_eval = set()
+        # Then set the options with those values
+        for key, val in self._get_ordered_configuration_items():
+            # '--' because configuration supports only long names
+            option = self.get_option('--' + key)
+
+            # Ignore options not present in this parser. E.g. non-globals put
+            # in [global] by users that want them to apply to all applicable
+            # commands.
+            if option is None:
+                continue
+
+            if option.action in ('store_true', 'store_false', 'count'):
+                try:
+                    val = strtobool(val)
+                except ValueError:
+                    error_msg = invalid_config_error_message(
+                        option.action, key, val
+                    )
+                    self.error(error_msg)
+
+            elif option.action == 'append':
+                val = val.split()
+                val = [self.check_default(option, key, v) for v in val]
+            elif option.action == 'callback':
+                late_eval.add(option.dest)
+                opt_str = option.get_opt_string()
+                val = option.convert_value(opt_str, val)
+                # From take_action
+                args = option.callback_args or ()
+                kwargs = option.callback_kwargs or {}
+                option.callback(option, opt_str, val, self, *args, **kwargs)
+            else:
+                val = self.check_default(option, key, val)
+
+            defaults[option.dest] = val
+
+        for key in late_eval:
+            defaults[key] = getattr(self.values, key)
+        self.values = None
+        return defaults
+
+    def get_default_values(self):
+        """Overriding to make updating the defaults after instantiation of
+        the option parser possible, _update_defaults() does the dirty work."""
+        if not self.process_default_values:
+            # Old, pre-Optik 1.5 behaviour.
+            return optparse.Values(self.defaults)
+
+        # Load the configuration, or error out in case of an error
+        try:
+            self.config.load()
+        except ConfigurationError as err:
+            self.exit(UNKNOWN_ERROR, str(err))
+
+        defaults = self._update_defaults(self.defaults.copy())  # ours
+        for option in self._get_all_options():
+            default = defaults.get(option.dest)
+            if isinstance(default, string_types):
+                opt_str = option.get_opt_string()
+                defaults[option.dest] = option.check_value(opt_str, default)
+        return optparse.Values(defaults)
+
+    def error(self, msg):
+        self.print_usage(sys.stderr)
+        self.exit(UNKNOWN_ERROR, "%s\n" % msg)
+
+
+def invalid_config_error_message(action, key, val):
+    """Returns a better error message when invalid configuration option
+    is provided."""
+    if action in ('store_true', 'store_false'):
+        return ("{0} is not a valid value for {1} option, "
+                "please specify a boolean value like yes/no, "
+                "true/false or 1/0 instead.").format(val, key)
+
+    return ("{0} is not a valid value for {1} option, "
+            "please specify a numerical value like 1/0 "
+            "instead.").format(val, key)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/req_command.py

@@ -0,0 +1,333 @@
+"""Contains the Command base classes that depend on PipSession.
+
+The classes in this module are in a separate module so the commands not
+needing download / PackageFinder capability don't unnecessarily import the
+PackageFinder machinery and all its vendored dependencies, etc.
+"""
+
+import logging
+import os
+from functools import partial
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.command_context import CommandContextMixIn
+from pip._internal.exceptions import CommandError
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.legacy_resolve import Resolver
+from pip._internal.models.selection_prefs import SelectionPreferences
+from pip._internal.network.download import Downloader
+from pip._internal.network.session import PipSession
+from pip._internal.operations.prepare import RequirementPreparer
+from pip._internal.req.constructors import (
+    install_req_from_editable,
+    install_req_from_line,
+    install_req_from_req_string,
+)
+from pip._internal.req.req_file import parse_requirements
+from pip._internal.self_outdated_check import (
+    make_link_collector,
+    pip_self_version_check,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import List, Optional, Tuple
+    from pip._internal.cache import WheelCache
+    from pip._internal.models.target_python import TargetPython
+    from pip._internal.req.req_set import RequirementSet
+    from pip._internal.req.req_tracker import RequirementTracker
+    from pip._internal.utils.temp_dir import TempDirectory
+
+logger = logging.getLogger(__name__)
+
+
+class SessionCommandMixin(CommandContextMixIn):
+
+    """
+    A class mixin for command classes needing _build_session().
+    """
+    def __init__(self):
+        # type: () -> None
+        super(SessionCommandMixin, self).__init__()
+        self._session = None  # Optional[PipSession]
+
+    @classmethod
+    def _get_index_urls(cls, options):
+        # type: (Values) -> Optional[List[str]]
+        """Return a list of index urls from user-provided options."""
+        index_urls = []
+        if not getattr(options, "no_index", False):
+            url = getattr(options, "index_url", None)
+            if url:
+                index_urls.append(url)
+        urls = getattr(options, "extra_index_urls", None)
+        if urls:
+            index_urls.extend(urls)
+        # Return None rather than an empty list
+        return index_urls or None
+
+    def get_default_session(self, options):
+        # type: (Values) -> PipSession
+        """Get a default-managed session."""
+        if self._session is None:
+            self._session = self.enter_context(self._build_session(options))
+            # there's no type annotation on requests.Session, so it's
+            # automatically ContextManager[Any] and self._session becomes Any,
+            # then https://github.com/python/mypy/issues/7696 kicks in
+            assert self._session is not None
+        return self._session
+
+    def _build_session(self, options, retries=None, timeout=None):
+        # type: (Values, Optional[int], Optional[int]) -> PipSession
+        assert not options.cache_dir or os.path.isabs(options.cache_dir)
+        session = PipSession(
+            cache=(
+                os.path.join(options.cache_dir, "http")
+                if options.cache_dir else None
+            ),
+            retries=retries if retries is not None else options.retries,
+            trusted_hosts=options.trusted_hosts,
+            index_urls=self._get_index_urls(options),
+        )
+
+        # Handle custom ca-bundles from the user
+        if options.cert:
+            session.verify = options.cert
+
+        # Handle SSL client certificate
+        if options.client_cert:
+            session.cert = options.client_cert
+
+        # Handle timeouts
+        if options.timeout or timeout:
+            session.timeout = (
+                timeout if timeout is not None else options.timeout
+            )
+
+        # Handle configured proxies
+        if options.proxy:
+            session.proxies = {
+                "http": options.proxy,
+                "https": options.proxy,
+            }
+
+        # Determine if we can prompt the user for authentication or not
+        session.auth.prompting = not options.no_input
+
+        return session
+
+
+class IndexGroupCommand(Command, SessionCommandMixin):
+
+    """
+    Abstract base class for commands with the index_group options.
+
+    This also corresponds to the commands that permit the pip version check.
+    """
+
+    def handle_pip_version_check(self, options):
+        # type: (Values) -> None
+        """
+        Do the pip version check if not disabled.
+
+        This overrides the default behavior of not doing the check.
+        """
+        # Make sure the index_group options are present.
+        assert hasattr(options, 'no_index')
+
+        if options.disable_pip_version_check or options.no_index:
+            return
+
+        # Otherwise, check if we're using the latest version of pip available.
+        session = self._build_session(
+            options,
+            retries=0,
+            timeout=min(5, options.timeout)
+        )
+        with session:
+            pip_self_version_check(session, options)
+
+
+class RequirementCommand(IndexGroupCommand):
+
+    @staticmethod
+    def make_requirement_preparer(
+        temp_build_dir,           # type: TempDirectory
+        options,                  # type: Values
+        req_tracker,              # type: RequirementTracker
+        session,                  # type: PipSession
+        finder,                   # type: PackageFinder
+        use_user_site,            # type: bool
+        download_dir=None,        # type: str
+        wheel_download_dir=None,  # type: str
+    ):
+        # type: (...) -> RequirementPreparer
+        """
+        Create a RequirementPreparer instance for the given parameters.
+        """
+        downloader = Downloader(session, progress_bar=options.progress_bar)
+
+        temp_build_dir_path = temp_build_dir.path
+        assert temp_build_dir_path is not None
+
+        return RequirementPreparer(
+            build_dir=temp_build_dir_path,
+            src_dir=options.src_dir,
+            download_dir=download_dir,
+            wheel_download_dir=wheel_download_dir,
+            build_isolation=options.build_isolation,
+            req_tracker=req_tracker,
+            downloader=downloader,
+            finder=finder,
+            require_hashes=options.require_hashes,
+            use_user_site=use_user_site,
+        )
+
+    @staticmethod
+    def make_resolver(
+        preparer,                            # type: RequirementPreparer
+        finder,                              # type: PackageFinder
+        options,                             # type: Values
+        wheel_cache=None,                    # type: Optional[WheelCache]
+        use_user_site=False,                 # type: bool
+        ignore_installed=True,               # type: bool
+        ignore_requires_python=False,        # type: bool
+        force_reinstall=False,               # type: bool
+        upgrade_strategy="to-satisfy-only",  # type: str
+        use_pep517=None,                     # type: Optional[bool]
+        py_version_info=None            # type: Optional[Tuple[int, ...]]
+    ):
+        # type: (...) -> Resolver
+        """
+        Create a Resolver instance for the given parameters.
+        """
+        make_install_req = partial(
+            install_req_from_req_string,
+            isolated=options.isolated_mode,
+            wheel_cache=wheel_cache,
+            use_pep517=use_pep517,
+        )
+        return Resolver(
+            preparer=preparer,
+            finder=finder,
+            make_install_req=make_install_req,
+            use_user_site=use_user_site,
+            ignore_dependencies=options.ignore_dependencies,
+            ignore_installed=ignore_installed,
+            ignore_requires_python=ignore_requires_python,
+            force_reinstall=force_reinstall,
+            upgrade_strategy=upgrade_strategy,
+            py_version_info=py_version_info,
+        )
+
+    def populate_requirement_set(
+        self,
+        requirement_set,  # type: RequirementSet
+        args,             # type: List[str]
+        options,          # type: Values
+        finder,           # type: PackageFinder
+        session,          # type: PipSession
+        wheel_cache,      # type: Optional[WheelCache]
+    ):
+        # type: (...) -> None
+        """
+        Marshal cmd line args into a requirement set.
+        """
+        for filename in options.constraints:
+            for req_to_add in parse_requirements(
+                    filename,
+                    constraint=True, finder=finder, options=options,
+                    session=session, wheel_cache=wheel_cache):
+                req_to_add.is_direct = True
+                requirement_set.add_requirement(req_to_add)
+
+        for req in args:
+            req_to_add = install_req_from_line(
+                req, None, isolated=options.isolated_mode,
+                use_pep517=options.use_pep517,
+                wheel_cache=wheel_cache
+            )
+            req_to_add.is_direct = True
+            requirement_set.add_requirement(req_to_add)
+
+        for req in options.editables:
+            req_to_add = install_req_from_editable(
+                req,
+                isolated=options.isolated_mode,
+                use_pep517=options.use_pep517,
+                wheel_cache=wheel_cache
+            )
+            req_to_add.is_direct = True
+            requirement_set.add_requirement(req_to_add)
+
+        # NOTE: options.require_hashes may be set if --require-hashes is True
+        for filename in options.requirements:
+            for req_to_add in parse_requirements(
+                    filename,
+                    finder=finder, options=options, session=session,
+                    wheel_cache=wheel_cache,
+                    use_pep517=options.use_pep517):
+                req_to_add.is_direct = True
+                requirement_set.add_requirement(req_to_add)
+
+        # If any requirement has hash options, enable hash checking.
+        requirements = (
+            requirement_set.unnamed_requirements +
+            list(requirement_set.requirements.values())
+        )
+        if any(req.has_hash_options for req in requirements):
+            options.require_hashes = True
+
+        if not (args or options.editables or options.requirements):
+            opts = {'name': self.name}
+            if options.find_links:
+                raise CommandError(
+                    'You must give at least one requirement to %(name)s '
+                    '(maybe you meant "pip %(name)s %(links)s"?)' %
+                    dict(opts, links=' '.join(options.find_links)))
+            else:
+                raise CommandError(
+                    'You must give at least one requirement to %(name)s '
+                    '(see "pip help %(name)s")' % opts)
+
+    @staticmethod
+    def trace_basic_info(finder):
+        # type: (PackageFinder) -> None
+        """
+        Trace basic information about the provided objects.
+        """
+        # Display where finder is looking for packages
+        search_scope = finder.search_scope
+        locations = search_scope.get_formatted_locations()
+        if locations:
+            logger.info(locations)
+
+    def _build_package_finder(
+        self,
+        options,               # type: Values
+        session,               # type: PipSession
+        target_python=None,    # type: Optional[TargetPython]
+        ignore_requires_python=None,  # type: Optional[bool]
+    ):
+        # type: (...) -> PackageFinder
+        """
+        Create a package finder appropriate to this requirement command.
+
+        :param ignore_requires_python: Whether to ignore incompatible
+            "Requires-Python" values in links. Defaults to False.
+        """
+        link_collector = make_link_collector(session, options=options)
+        selection_prefs = SelectionPreferences(
+            allow_yanked=True,
+            format_control=options.format_control,
+            allow_all_prereleases=options.pre,
+            prefer_binary=options.prefer_binary,
+            ignore_requires_python=ignore_requires_python,
+        )
+
+        return PackageFinder.create(
+            link_collector=link_collector,
+            selection_prefs=selection_prefs,
+            target_python=target_python,
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/cli/status_codes.py

@@ -0,0 +1,8 @@
+from __future__ import absolute_import
+
+SUCCESS = 0
+ERROR = 1
+UNKNOWN_ERROR = 2
+VIRTUALENV_NOT_FOUND = 3
+PREVIOUS_BUILD_DIR_ERROR = 4
+NO_MATCHES_FOUND = 23

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/__init__.py

@@ -0,0 +1,114 @@
+"""
+Package containing all pip commands
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import importlib
+from collections import OrderedDict, namedtuple
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any
+    from pip._internal.cli.base_command import Command
+
+
+CommandInfo = namedtuple('CommandInfo', 'module_path, class_name, summary')
+
+# The ordering matters for help display.
+#    Also, even though the module path starts with the same
+# "pip._internal.commands" prefix in each case, we include the full path
+# because it makes testing easier (specifically when modifying commands_dict
+# in test setup / teardown by adding info for a FakeCommand class defined
+# in a test-related module).
+#    Finally, we need to pass an iterable of pairs here rather than a dict
+# so that the ordering won't be lost when using Python 2.7.
+commands_dict = OrderedDict([
+    ('install', CommandInfo(
+        'pip._internal.commands.install', 'InstallCommand',
+        'Install packages.',
+    )),
+    ('download', CommandInfo(
+        'pip._internal.commands.download', 'DownloadCommand',
+        'Download packages.',
+    )),
+    ('uninstall', CommandInfo(
+        'pip._internal.commands.uninstall', 'UninstallCommand',
+        'Uninstall packages.',
+    )),
+    ('freeze', CommandInfo(
+        'pip._internal.commands.freeze', 'FreezeCommand',
+        'Output installed packages in requirements format.',
+    )),
+    ('list', CommandInfo(
+        'pip._internal.commands.list', 'ListCommand',
+        'List installed packages.',
+    )),
+    ('show', CommandInfo(
+        'pip._internal.commands.show', 'ShowCommand',
+        'Show information about installed packages.',
+    )),
+    ('check', CommandInfo(
+        'pip._internal.commands.check', 'CheckCommand',
+        'Verify installed packages have compatible dependencies.',
+    )),
+    ('config', CommandInfo(
+        'pip._internal.commands.configuration', 'ConfigurationCommand',
+        'Manage local and global configuration.',
+    )),
+    ('search', CommandInfo(
+        'pip._internal.commands.search', 'SearchCommand',
+        'Search PyPI for packages.',
+    )),
+    ('wheel', CommandInfo(
+        'pip._internal.commands.wheel', 'WheelCommand',
+        'Build wheels from your requirements.',
+    )),
+    ('hash', CommandInfo(
+        'pip._internal.commands.hash', 'HashCommand',
+        'Compute hashes of package archives.',
+    )),
+    ('completion', CommandInfo(
+        'pip._internal.commands.completion', 'CompletionCommand',
+        'A helper command used for command completion.',
+    )),
+    ('debug', CommandInfo(
+        'pip._internal.commands.debug', 'DebugCommand',
+        'Show information useful for debugging.',
+    )),
+    ('help', CommandInfo(
+        'pip._internal.commands.help', 'HelpCommand',
+        'Show help for commands.',
+    )),
+])  # type: OrderedDict[str, CommandInfo]
+
+
+def create_command(name, **kwargs):
+    # type: (str, **Any) -> Command
+    """
+    Create an instance of the Command class with the given name.
+    """
+    module_path, class_name, summary = commands_dict[name]
+    module = importlib.import_module(module_path)
+    command_class = getattr(module, class_name)
+    command = command_class(name=name, summary=summary, **kwargs)
+
+    return command
+
+
+def get_similar_commands(name):
+    """Command name auto-correct."""
+    from difflib import get_close_matches
+
+    name = name.lower()
+
+    close_commands = get_close_matches(name, commands_dict.keys())
+
+    if close_commands:
+        return close_commands[0]
+    else:
+        return False

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/check.py

@@ -0,0 +1,45 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+
+from pip._internal.cli.base_command import Command
+from pip._internal.operations.check import (
+    check_package_set,
+    create_package_set_from_installed,
+)
+from pip._internal.utils.misc import write_output
+
+logger = logging.getLogger(__name__)
+
+
+class CheckCommand(Command):
+    """Verify installed packages have compatible dependencies."""
+
+    usage = """
+      %prog [options]"""
+
+    def run(self, options, args):
+        package_set, parsing_probs = create_package_set_from_installed()
+        missing, conflicting = check_package_set(package_set)
+
+        for project_name in missing:
+            version = package_set[project_name].version
+            for dependency in missing[project_name]:
+                write_output(
+                    "%s %s requires %s, which is not installed.",
+                    project_name, version, dependency[0],
+                )
+
+        for project_name in conflicting:
+            version = package_set[project_name].version
+            for dep_name, dep_version, req in conflicting[project_name]:
+                write_output(
+                    "%s %s has requirement %s, but you have %s %s.",
+                    project_name, version, req, dep_name, dep_version,
+                )
+
+        if missing or conflicting or parsing_probs:
+            return 1
+        else:
+            write_output("No broken requirements found.")

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/completion.py

@@ -0,0 +1,96 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import sys
+import textwrap
+
+from pip._internal.cli.base_command import Command
+from pip._internal.utils.misc import get_prog
+
+BASE_COMPLETION = """
+# pip %(shell)s completion start%(script)s# pip %(shell)s completion end
+"""
+
+COMPLETION_SCRIPTS = {
+    'bash': """
+        _pip_completion()
+        {
+            COMPREPLY=( $( COMP_WORDS="${COMP_WORDS[*]}" \\
+                           COMP_CWORD=$COMP_CWORD \\
+                           PIP_AUTO_COMPLETE=1 $1 2>/dev/null ) )
+        }
+        complete -o default -F _pip_completion %(prog)s
+    """,
+    'zsh': """
+        function _pip_completion {
+          local words cword
+          read -Ac words
+          read -cn cword
+          reply=( $( COMP_WORDS="$words[*]" \\
+                     COMP_CWORD=$(( cword-1 )) \\
+                     PIP_AUTO_COMPLETE=1 $words[1] 2>/dev/null ))
+        }
+        compctl -K _pip_completion %(prog)s
+    """,
+    'fish': """
+        function __fish_complete_pip
+            set -lx COMP_WORDS (commandline -o) ""
+            set -lx COMP_CWORD ( \\
+                math (contains -i -- (commandline -t) $COMP_WORDS)-1 \\
+            )
+            set -lx PIP_AUTO_COMPLETE 1
+            string split \\  -- (eval $COMP_WORDS[1])
+        end
+        complete -fa "(__fish_complete_pip)" -c %(prog)s
+    """,
+}
+
+
+class CompletionCommand(Command):
+    """A helper command to be used for command completion."""
+
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(CompletionCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(
+            '--bash', '-b',
+            action='store_const',
+            const='bash',
+            dest='shell',
+            help='Emit completion code for bash')
+        cmd_opts.add_option(
+            '--zsh', '-z',
+            action='store_const',
+            const='zsh',
+            dest='shell',
+            help='Emit completion code for zsh')
+        cmd_opts.add_option(
+            '--fish', '-f',
+            action='store_const',
+            const='fish',
+            dest='shell',
+            help='Emit completion code for fish')
+
+        self.parser.insert_option_group(0, cmd_opts)
+
+    def run(self, options, args):
+        """Prints the completion code of the given shell"""
+        shells = COMPLETION_SCRIPTS.keys()
+        shell_options = ['--' + shell for shell in sorted(shells)]
+        if options.shell in shells:
+            script = textwrap.dedent(
+                COMPLETION_SCRIPTS.get(options.shell, '') % {
+                    'prog': get_prog(),
+                }
+            )
+            print(BASE_COMPLETION % {'script': script, 'shell': options.shell})
+        else:
+            sys.stderr.write(
+                'ERROR: You must pass %s\n' % ' or '.join(shell_options)
+            )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/configuration.py

@@ -0,0 +1,233 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+import os
+import subprocess
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.configuration import (
+    Configuration,
+    get_configuration_files,
+    kinds,
+)
+from pip._internal.exceptions import PipError
+from pip._internal.utils.misc import get_prog, write_output
+
+logger = logging.getLogger(__name__)
+
+
+class ConfigurationCommand(Command):
+    """Manage local and global configuration.
+
+        Subcommands:
+
+        list: List the active configuration (or from the file specified)
+        edit: Edit the configuration file in an editor
+        get: Get the value associated with name
+        set: Set the name=value
+        unset: Unset the value associated with name
+
+        If none of --user, --global and --site are passed, a virtual
+        environment configuration file is used if one is active and the file
+        exists. Otherwise, all modifications happen on the to the user file by
+        default.
+    """
+
+    ignore_require_venv = True
+    usage = """
+        %prog [<file-option>] list
+        %prog [<file-option>] [--editor <editor-path>] edit
+
+        %prog [<file-option>] get name
+        %prog [<file-option>] set name value
+        %prog [<file-option>] unset name
+    """
+
+    def __init__(self, *args, **kwargs):
+        super(ConfigurationCommand, self).__init__(*args, **kwargs)
+
+        self.configuration = None
+
+        self.cmd_opts.add_option(
+            '--editor',
+            dest='editor',
+            action='store',
+            default=None,
+            help=(
+                'Editor to use to edit the file. Uses VISUAL or EDITOR '
+                'environment variables if not provided.'
+            )
+        )
+
+        self.cmd_opts.add_option(
+            '--global',
+            dest='global_file',
+            action='store_true',
+            default=False,
+            help='Use the system-wide configuration file only'
+        )
+
+        self.cmd_opts.add_option(
+            '--user',
+            dest='user_file',
+            action='store_true',
+            default=False,
+            help='Use the user configuration file only'
+        )
+
+        self.cmd_opts.add_option(
+            '--site',
+            dest='site_file',
+            action='store_true',
+            default=False,
+            help='Use the current environment configuration file only'
+        )
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        handlers = {
+            "list": self.list_values,
+            "edit": self.open_in_editor,
+            "get": self.get_name,
+            "set": self.set_name_value,
+            "unset": self.unset_name
+        }
+
+        # Determine action
+        if not args or args[0] not in handlers:
+            logger.error("Need an action ({}) to perform.".format(
+                ", ".join(sorted(handlers)))
+            )
+            return ERROR
+
+        action = args[0]
+
+        # Determine which configuration files are to be loaded
+        #    Depends on whether the command is modifying.
+        try:
+            load_only = self._determine_file(
+                options, need_value=(action in ["get", "set", "unset", "edit"])
+            )
+        except PipError as e:
+            logger.error(e.args[0])
+            return ERROR
+
+        # Load a new configuration
+        self.configuration = Configuration(
+            isolated=options.isolated_mode, load_only=load_only
+        )
+        self.configuration.load()
+
+        # Error handling happens here, not in the action-handlers.
+        try:
+            handlers[action](options, args[1:])
+        except PipError as e:
+            logger.error(e.args[0])
+            return ERROR
+
+        return SUCCESS
+
+    def _determine_file(self, options, need_value):
+        file_options = [key for key, value in (
+            (kinds.USER, options.user_file),
+            (kinds.GLOBAL, options.global_file),
+            (kinds.SITE, options.site_file),
+        ) if value]
+
+        if not file_options:
+            if not need_value:
+                return None
+            # Default to user, unless there's a site file.
+            elif any(
+                os.path.exists(site_config_file)
+                for site_config_file in get_configuration_files()[kinds.SITE]
+            ):
+                return kinds.SITE
+            else:
+                return kinds.USER
+        elif len(file_options) == 1:
+            return file_options[0]
+
+        raise PipError(
+            "Need exactly one file to operate upon "
+            "(--user, --site, --global) to perform."
+        )
+
+    def list_values(self, options, args):
+        self._get_n_args(args, "list", n=0)
+
+        for key, value in sorted(self.configuration.items()):
+            write_output("%s=%r", key, value)
+
+    def get_name(self, options, args):
+        key = self._get_n_args(args, "get [name]", n=1)
+        value = self.configuration.get_value(key)
+
+        write_output("%s", value)
+
+    def set_name_value(self, options, args):
+        key, value = self._get_n_args(args, "set [name] [value]", n=2)
+        self.configuration.set_value(key, value)
+
+        self._save_configuration()
+
+    def unset_name(self, options, args):
+        key = self._get_n_args(args, "unset [name]", n=1)
+        self.configuration.unset_value(key)
+
+        self._save_configuration()
+
+    def open_in_editor(self, options, args):
+        editor = self._determine_editor(options)
+
+        fname = self.configuration.get_file_to_edit()
+        if fname is None:
+            raise PipError("Could not determine appropriate file.")
+
+        try:
+            subprocess.check_call([editor, fname])
+        except subprocess.CalledProcessError as e:
+            raise PipError(
+                "Editor Subprocess exited with exit code {}"
+                .format(e.returncode)
+            )
+
+    def _get_n_args(self, args, example, n):
+        """Helper to make sure the command got the right number of arguments
+        """
+        if len(args) != n:
+            msg = (
+                'Got unexpected number of arguments, expected {}. '
+                '(example: "{} config {}")'
+            ).format(n, get_prog(), example)
+            raise PipError(msg)
+
+        if n == 1:
+            return args[0]
+        else:
+            return args
+
+    def _save_configuration(self):
+        # We successfully ran a modifying command. Need to save the
+        # configuration.
+        try:
+            self.configuration.save()
+        except Exception:
+            logger.error(
+                "Unable to save configuration. Please report this as a bug.",
+                exc_info=1
+            )
+            raise PipError("Internal Error.")
+
+    def _determine_editor(self, options):
+        if options.editor is not None:
+            return options.editor
+        elif "VISUAL" in os.environ:
+            return os.environ["VISUAL"]
+        elif "EDITOR" in os.environ:
+            return os.environ["EDITOR"]
+        else:
+            raise PipError("Could not determine editor to use.")

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/debug.py

@@ -0,0 +1,142 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import locale
+import logging
+import os
+import sys
+
+from pip._vendor.certifi import where
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.cmdoptions import make_target_python
+from pip._internal.cli.status_codes import SUCCESS
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import get_pip_version
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, List, Optional
+    from optparse import Values
+
+logger = logging.getLogger(__name__)
+
+
+def show_value(name, value):
+    # type: (str, Optional[str]) -> None
+    logger.info('{}: {}'.format(name, value))
+
+
+def show_sys_implementation():
+    # type: () -> None
+    logger.info('sys.implementation:')
+    if hasattr(sys, 'implementation'):
+        implementation = sys.implementation  # type: ignore
+        implementation_name = implementation.name
+    else:
+        implementation_name = ''
+
+    with indent_log():
+        show_value('name', implementation_name)
+
+
+def show_tags(options):
+    # type: (Values) -> None
+    tag_limit = 10
+
+    target_python = make_target_python(options)
+    tags = target_python.get_tags()
+
+    # Display the target options that were explicitly provided.
+    formatted_target = target_python.format_given()
+    suffix = ''
+    if formatted_target:
+        suffix = ' (target: {})'.format(formatted_target)
+
+    msg = 'Compatible tags: {}{}'.format(len(tags), suffix)
+    logger.info(msg)
+
+    if options.verbose < 1 and len(tags) > tag_limit:
+        tags_limited = True
+        tags = tags[:tag_limit]
+    else:
+        tags_limited = False
+
+    with indent_log():
+        for tag in tags:
+            logger.info(str(tag))
+
+        if tags_limited:
+            msg = (
+                '...\n'
+                '[First {tag_limit} tags shown. Pass --verbose to show all.]'
+            ).format(tag_limit=tag_limit)
+            logger.info(msg)
+
+
+def ca_bundle_info(config):
+    levels = set()
+    for key, value in config.items():
+        levels.add(key.split('.')[0])
+
+    if not levels:
+        return "Not specified"
+
+    levels_that_override_global = ['install', 'wheel', 'download']
+    global_overriding_level = [
+        level for level in levels if level in levels_that_override_global
+    ]
+    if not global_overriding_level:
+        return 'global'
+
+    levels.remove('global')
+    return ", ".join(levels)
+
+
+class DebugCommand(Command):
+    """
+    Display debug information.
+    """
+
+    usage = """
+      %prog <options>"""
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(DebugCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+        cmdoptions.add_target_python_options(cmd_opts)
+        self.parser.insert_option_group(0, cmd_opts)
+        self.parser.config.load()
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> int
+        logger.warning(
+            "This command is only meant for debugging. "
+            "Do not use this with automation for parsing and getting these "
+            "details, since the output and options of this command may "
+            "change without notice."
+        )
+        show_value('pip version', get_pip_version())
+        show_value('sys.version', sys.version)
+        show_value('sys.executable', sys.executable)
+        show_value('sys.getdefaultencoding', sys.getdefaultencoding())
+        show_value('sys.getfilesystemencoding', sys.getfilesystemencoding())
+        show_value(
+            'locale.getpreferredencoding', locale.getpreferredencoding(),
+        )
+        show_value('sys.platform', sys.platform)
+        show_sys_implementation()
+
+        show_value("'cert' config value", ca_bundle_info(self.parser.config))
+        show_value("REQUESTS_CA_BUNDLE", os.environ.get('REQUESTS_CA_BUNDLE'))
+        show_value("CURL_CA_BUNDLE", os.environ.get('CURL_CA_BUNDLE'))
+        show_value("pip._vendor.certifi.where()", where())
+
+        show_tags(options)
+
+        return SUCCESS

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/download.py

@@ -0,0 +1,147 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.cmdoptions import make_target_python
+from pip._internal.cli.req_command import RequirementCommand
+from pip._internal.req import RequirementSet
+from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.misc import ensure_dir, normalize_path, write_output
+from pip._internal.utils.temp_dir import TempDirectory
+
+logger = logging.getLogger(__name__)
+
+
+class DownloadCommand(RequirementCommand):
+    """
+    Download packages from:
+
+    - PyPI (and other indexes) using requirement specifiers.
+    - VCS project urls.
+    - Local project directories.
+    - Local or remote source archives.
+
+    pip also supports downloading from "requirements files", which provide
+    an easy way to specify a whole environment to be downloaded.
+    """
+
+    usage = """
+      %prog [options] <requirement specifier> [package-index-options] ...
+      %prog [options] -r <requirements file> [package-index-options] ...
+      %prog [options] <vcs project url> ...
+      %prog [options] <local project path> ...
+      %prog [options] <archive url/path> ..."""
+
+    def __init__(self, *args, **kw):
+        super(DownloadCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(cmdoptions.constraints())
+        cmd_opts.add_option(cmdoptions.requirements())
+        cmd_opts.add_option(cmdoptions.build_dir())
+        cmd_opts.add_option(cmdoptions.no_deps())
+        cmd_opts.add_option(cmdoptions.global_options())
+        cmd_opts.add_option(cmdoptions.no_binary())
+        cmd_opts.add_option(cmdoptions.only_binary())
+        cmd_opts.add_option(cmdoptions.prefer_binary())
+        cmd_opts.add_option(cmdoptions.src())
+        cmd_opts.add_option(cmdoptions.pre())
+        cmd_opts.add_option(cmdoptions.no_clean())
+        cmd_opts.add_option(cmdoptions.require_hashes())
+        cmd_opts.add_option(cmdoptions.progress_bar())
+        cmd_opts.add_option(cmdoptions.no_build_isolation())
+        cmd_opts.add_option(cmdoptions.use_pep517())
+        cmd_opts.add_option(cmdoptions.no_use_pep517())
+
+        cmd_opts.add_option(
+            '-d', '--dest', '--destination-dir', '--destination-directory',
+            dest='download_dir',
+            metavar='dir',
+            default=os.curdir,
+            help=("Download packages into <dir>."),
+        )
+
+        cmdoptions.add_target_python_options(cmd_opts)
+
+        index_opts = cmdoptions.make_option_group(
+            cmdoptions.index_group,
+            self.parser,
+        )
+
+        self.parser.insert_option_group(0, index_opts)
+        self.parser.insert_option_group(0, cmd_opts)
+
+    def run(self, options, args):
+        options.ignore_installed = True
+        # editable doesn't really make sense for `pip download`, but the bowels
+        # of the RequirementSet code require that property.
+        options.editables = []
+
+        cmdoptions.check_dist_restriction(options)
+
+        options.download_dir = normalize_path(options.download_dir)
+
+        ensure_dir(options.download_dir)
+
+        session = self.get_default_session(options)
+
+        target_python = make_target_python(options)
+        finder = self._build_package_finder(
+            options=options,
+            session=session,
+            target_python=target_python,
+        )
+        build_delete = (not (options.no_clean or options.build_dir))
+
+        with get_requirement_tracker() as req_tracker, TempDirectory(
+            options.build_dir, delete=build_delete, kind="download"
+        ) as directory:
+
+            requirement_set = RequirementSet()
+            self.populate_requirement_set(
+                requirement_set,
+                args,
+                options,
+                finder,
+                session,
+                None
+            )
+
+            preparer = self.make_requirement_preparer(
+                temp_build_dir=directory,
+                options=options,
+                req_tracker=req_tracker,
+                session=session,
+                finder=finder,
+                download_dir=options.download_dir,
+                use_user_site=False,
+            )
+
+            resolver = self.make_resolver(
+                preparer=preparer,
+                finder=finder,
+                options=options,
+                py_version_info=options.python_version,
+            )
+
+            self.trace_basic_info(finder)
+
+            resolver.resolve(requirement_set)
+
+            downloaded = ' '.join([
+                req.name for req in requirement_set.successfully_downloaded
+            ])
+            if downloaded:
+                write_output('Successfully downloaded %s', downloaded)
+
+            # Clean up
+            if not options.no_clean:
+                requirement_set.cleanup_files()
+
+        return requirement_set

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/freeze.py

@@ -0,0 +1,103 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import sys
+
+from pip._internal.cache import WheelCache
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.base_command import Command
+from pip._internal.models.format_control import FormatControl
+from pip._internal.operations.freeze import freeze
+from pip._internal.utils.compat import stdlib_pkgs
+
+DEV_PKGS = {'pip', 'setuptools', 'distribute', 'wheel', 'pkg-resources'}
+
+
+class FreezeCommand(Command):
+    """
+    Output installed packages in requirements format.
+
+    packages are listed in a case-insensitive sorted order.
+    """
+
+    usage = """
+      %prog [options]"""
+    log_streams = ("ext://sys.stderr", "ext://sys.stderr")
+
+    def __init__(self, *args, **kw):
+        super(FreezeCommand, self).__init__(*args, **kw)
+
+        self.cmd_opts.add_option(
+            '-r', '--requirement',
+            dest='requirements',
+            action='append',
+            default=[],
+            metavar='file',
+            help="Use the order in the given requirements file and its "
+                 "comments when generating output. This option can be "
+                 "used multiple times.")
+        self.cmd_opts.add_option(
+            '-f', '--find-links',
+            dest='find_links',
+            action='append',
+            default=[],
+            metavar='URL',
+            help='URL for finding packages, which will be added to the '
+                 'output.')
+        self.cmd_opts.add_option(
+            '-l', '--local',
+            dest='local',
+            action='store_true',
+            default=False,
+            help='If in a virtualenv that has global access, do not output '
+                 'globally-installed packages.')
+        self.cmd_opts.add_option(
+            '--user',
+            dest='user',
+            action='store_true',
+            default=False,
+            help='Only output packages installed in user-site.')
+        self.cmd_opts.add_option(cmdoptions.list_path())
+        self.cmd_opts.add_option(
+            '--all',
+            dest='freeze_all',
+            action='store_true',
+            help='Do not skip these packages in the output:'
+                 ' %s' % ', '.join(DEV_PKGS))
+        self.cmd_opts.add_option(
+            '--exclude-editable',
+            dest='exclude_editable',
+            action='store_true',
+            help='Exclude editable package from output.')
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        format_control = FormatControl(set(), set())
+        wheel_cache = WheelCache(options.cache_dir, format_control)
+        skip = set(stdlib_pkgs)
+        if not options.freeze_all:
+            skip.update(DEV_PKGS)
+
+        cmdoptions.check_list_path_option(options)
+
+        freeze_kwargs = dict(
+            requirement=options.requirements,
+            find_links=options.find_links,
+            local_only=options.local,
+            user_only=options.user,
+            paths=options.path,
+            skip_regex=options.skip_requirements_regex,
+            isolated=options.isolated_mode,
+            wheel_cache=wheel_cache,
+            skip=skip,
+            exclude_editable=options.exclude_editable,
+        )
+
+        try:
+            for line in freeze(**freeze_kwargs):
+                sys.stdout.write(line + '\n')
+        finally:
+            wheel_cache.cleanup()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/hash.py

@@ -0,0 +1,58 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import hashlib
+import logging
+import sys
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import ERROR
+from pip._internal.utils.hashes import FAVORITE_HASH, STRONG_HASHES
+from pip._internal.utils.misc import read_chunks, write_output
+
+logger = logging.getLogger(__name__)
+
+
+class HashCommand(Command):
+    """
+    Compute a hash of a local package archive.
+
+    These can be used with --hash in a requirements file to do repeatable
+    installs.
+    """
+
+    usage = '%prog [options] <file> ...'
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(HashCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-a', '--algorithm',
+            dest='algorithm',
+            choices=STRONG_HASHES,
+            action='store',
+            default=FAVORITE_HASH,
+            help='The hash algorithm to use: one of %s' %
+                 ', '.join(STRONG_HASHES))
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        if not args:
+            self.parser.print_usage(sys.stderr)
+            return ERROR
+
+        algorithm = options.algorithm
+        for path in args:
+            write_output('%s:\n--hash=%s:%s',
+                         path, algorithm, _hash_of_file(path, algorithm))
+
+
+def _hash_of_file(path, algorithm):
+    """Return the hash digest of a file."""
+    with open(path, 'rb') as archive:
+        hash = hashlib.new(algorithm)
+        for chunk in read_chunks(archive):
+            hash.update(chunk)
+    return hash.hexdigest()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/help.py

@@ -0,0 +1,41 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import SUCCESS
+from pip._internal.exceptions import CommandError
+
+
+class HelpCommand(Command):
+    """Show help for commands"""
+
+    usage = """
+      %prog <command>"""
+    ignore_require_venv = True
+
+    def run(self, options, args):
+        from pip._internal.commands import (
+            commands_dict, create_command, get_similar_commands,
+        )
+
+        try:
+            # 'pip help' with no args is handled by pip.__init__.parseopt()
+            cmd_name = args[0]  # the command we need help for
+        except IndexError:
+            return SUCCESS
+
+        if cmd_name not in commands_dict:
+            guess = get_similar_commands(cmd_name)
+
+            msg = ['unknown command "%s"' % cmd_name]
+            if guess:
+                msg.append('maybe you meant "%s"' % guess)
+
+            raise CommandError(' - '.join(msg))
+
+        command = create_command(cmd_name)
+        command.parser.print_help()
+
+        return SUCCESS

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/install.py

@@ -0,0 +1,727 @@
+# The following comment should be removed at some point in the future.
+# It's included for now because without it InstallCommand.run() has a
+# couple errors where we have to know req.name is str rather than
+# Optional[str] for the InstallRequirement req.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import errno
+import logging
+import operator
+import os
+import shutil
+import site
+from optparse import SUPPRESS_HELP
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.cache import WheelCache
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.cmdoptions import make_target_python
+from pip._internal.cli.req_command import RequirementCommand
+from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.exceptions import (
+    CommandError,
+    InstallationError,
+    PreviousBuildDirError,
+)
+from pip._internal.locations import distutils_scheme
+from pip._internal.operations.check import check_install_conflicts
+from pip._internal.req import RequirementSet, install_given_reqs
+from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.deprecation import deprecated
+from pip._internal.utils.distutils_args import parse_distutils_args
+from pip._internal.utils.filesystem import test_writable_dir
+from pip._internal.utils.misc import (
+    ensure_dir,
+    get_installed_version,
+    protect_pip_from_modification_on_windows,
+    write_output,
+)
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.virtualenv import virtualenv_no_global
+from pip._internal.wheel_builder import build, should_build_for_install_command
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import Any, Iterable, List, Optional
+
+    from pip._internal.models.format_control import FormatControl
+    from pip._internal.req.req_install import InstallRequirement
+    from pip._internal.wheel_builder import BinaryAllowedPredicate
+
+from pip._internal.locations import running_under_virtualenv
+
+logger = logging.getLogger(__name__)
+
+
+def get_check_binary_allowed(format_control):
+    # type: (FormatControl) -> BinaryAllowedPredicate
+    def check_binary_allowed(req):
+        # type: (InstallRequirement) -> bool
+        if req.use_pep517:
+            return True
+        canonical_name = canonicalize_name(req.name)
+        allowed_formats = format_control.get_allowed_formats(canonical_name)
+        return "binary" in allowed_formats
+
+    return check_binary_allowed
+
+
+class InstallCommand(RequirementCommand):
+    """
+    Install packages from:
+
+    - PyPI (and other indexes) using requirement specifiers.
+    - VCS project urls.
+    - Local project directories.
+    - Local or remote source archives.
+
+    pip also supports installing from "requirements files", which provide
+    an easy way to specify a whole environment to be installed.
+    """
+
+    usage = """
+      %prog [options] <requirement specifier> [package-index-options] ...
+      %prog [options] -r <requirements file> [package-index-options] ...
+      %prog [options] [-e] <vcs project url> ...
+      %prog [options] [-e] <local project path> ...
+      %prog [options] <archive url/path> ..."""
+
+    def __init__(self, *args, **kw):
+        super(InstallCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(cmdoptions.requirements())
+        cmd_opts.add_option(cmdoptions.constraints())
+        cmd_opts.add_option(cmdoptions.no_deps())
+        cmd_opts.add_option(cmdoptions.pre())
+
+        cmd_opts.add_option(cmdoptions.editable())
+        cmd_opts.add_option(
+            '-t', '--target',
+            dest='target_dir',
+            metavar='dir',
+            default=None,
+            help='Install packages into <dir>. '
+                 'By default this will not replace existing files/folders in '
+                 '<dir>. Use --upgrade to replace existing packages in <dir> '
+                 'with new versions.'
+        )
+        cmdoptions.add_target_python_options(cmd_opts)
+
+        cmd_opts.add_option(
+            '--user',
+            dest='use_user_site',
+            action='store_true',
+            help="Install to the Python user install directory for your "
+                 "platform. Typically ~/.local/, or %APPDATA%\\Python on "
+                 "Windows. (See the Python documentation for site.USER_BASE "
+                 "for full details.)  On Debian systems, this is the "
+                 "default when running outside of a virtual environment "
+                 "and not as root.")
+
+        cmd_opts.add_option(
+            '--no-user',
+            dest='use_system_location',
+            action='store_true',
+            help=SUPPRESS_HELP)
+        cmd_opts.add_option(
+            '--root',
+            dest='root_path',
+            metavar='dir',
+            default=None,
+            help="Install everything relative to this alternate root "
+                 "directory.")
+        cmd_opts.add_option(
+            '--prefix',
+            dest='prefix_path',
+            metavar='dir',
+            default=None,
+            help="Installation prefix where lib, bin and other top-level "
+                 "folders are placed")
+
+        cmd_opts.add_option(
+            '--system',
+            dest='use_system_location',
+            action='store_true',
+            help="Install using the system scheme (overrides --user on "
+                 "Debian systems)")
+
+        cmd_opts.add_option(cmdoptions.build_dir())
+
+        cmd_opts.add_option(cmdoptions.src())
+
+        cmd_opts.add_option(
+            '-U', '--upgrade',
+            dest='upgrade',
+            action='store_true',
+            help='Upgrade all specified packages to the newest available '
+                 'version. The handling of dependencies depends on the '
+                 'upgrade-strategy used.'
+        )
+
+        cmd_opts.add_option(
+            '--upgrade-strategy',
+            dest='upgrade_strategy',
+            default='only-if-needed',
+            choices=['only-if-needed', 'eager'],
+            help='Determines how dependency upgrading should be handled '
+                 '[default: %default]. '
+                 '"eager" - dependencies are upgraded regardless of '
+                 'whether the currently installed version satisfies the '
+                 'requirements of the upgraded package(s). '
+                 '"only-if-needed" -  are upgraded only when they do not '
+                 'satisfy the requirements of the upgraded package(s).'
+        )
+
+        cmd_opts.add_option(
+            '--force-reinstall',
+            dest='force_reinstall',
+            action='store_true',
+            help='Reinstall all packages even if they are already '
+                 'up-to-date.')
+
+        cmd_opts.add_option(
+            '-I', '--ignore-installed',
+            dest='ignore_installed',
+            action='store_true',
+            help='Ignore the installed packages, overwriting them. '
+                 'This can break your system if the existing package '
+                 'is of a different version or was installed '
+                 'with a different package manager!'
+        )
+
+        cmd_opts.add_option(cmdoptions.ignore_requires_python())
+        cmd_opts.add_option(cmdoptions.no_build_isolation())
+        cmd_opts.add_option(cmdoptions.use_pep517())
+        cmd_opts.add_option(cmdoptions.no_use_pep517())
+
+        cmd_opts.add_option(cmdoptions.install_options())
+        cmd_opts.add_option(cmdoptions.global_options())
+
+        cmd_opts.add_option(
+            "--compile",
+            action="store_true",
+            dest="compile",
+            default=True,
+            help="Compile Python source files to bytecode",
+        )
+
+        cmd_opts.add_option(
+            "--no-compile",
+            action="store_false",
+            dest="compile",
+            help="Do not compile Python source files to bytecode",
+        )
+
+        cmd_opts.add_option(
+            "--no-warn-script-location",
+            action="store_false",
+            dest="warn_script_location",
+            default=True,
+            help="Do not warn when installing scripts outside PATH",
+        )
+        cmd_opts.add_option(
+            "--no-warn-conflicts",
+            action="store_false",
+            dest="warn_about_conflicts",
+            default=True,
+            help="Do not warn about broken dependencies",
+        )
+
+        cmd_opts.add_option(cmdoptions.no_binary())
+        cmd_opts.add_option(cmdoptions.only_binary())
+        cmd_opts.add_option(cmdoptions.prefer_binary())
+        cmd_opts.add_option(cmdoptions.no_clean())
+        cmd_opts.add_option(cmdoptions.require_hashes())
+        cmd_opts.add_option(cmdoptions.progress_bar())
+
+        index_opts = cmdoptions.make_option_group(
+            cmdoptions.index_group,
+            self.parser,
+        )
+
+        self.parser.insert_option_group(0, index_opts)
+        self.parser.insert_option_group(0, cmd_opts)
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> int
+        cmdoptions.check_install_build_global(options)
+        upgrade_strategy = "to-satisfy-only"
+        if options.upgrade:
+            upgrade_strategy = options.upgrade_strategy
+
+        cmdoptions.check_dist_restriction(options, check_target=True)
+
+        if options.python_version:
+            python_versions = [options.python_version]
+        else:
+            python_versions = None
+
+        # compute install location defaults
+        if (not options.use_user_site and not options.prefix_path and not
+                options.target_dir and not options.use_system_location):
+            if not running_under_virtualenv() and os.geteuid() != 0:
+                options.use_user_site = True
+
+        if options.use_system_location:
+            options.use_user_site = False
+
+        options.src_dir = os.path.abspath(options.src_dir)
+        install_options = options.install_options or []
+
+        options.use_user_site = decide_user_install(
+            options.use_user_site,
+            prefix_path=options.prefix_path,
+            target_dir=options.target_dir,
+            root_path=options.root_path,
+            isolated_mode=options.isolated_mode,
+        )
+
+        target_temp_dir = None  # type: Optional[TempDirectory]
+        target_temp_dir_path = None  # type: Optional[str]
+        if options.target_dir:
+            options.ignore_installed = True
+            options.target_dir = os.path.abspath(options.target_dir)
+            if (os.path.exists(options.target_dir) and not
+                    os.path.isdir(options.target_dir)):
+                raise CommandError(
+                    "Target path exists but is not a directory, will not "
+                    "continue."
+                )
+
+            # Create a target directory for using with the target option
+            target_temp_dir = TempDirectory(kind="target")
+            target_temp_dir_path = target_temp_dir.path
+
+        global_options = options.global_options or []
+
+        session = self.get_default_session(options)
+
+        target_python = make_target_python(options)
+        finder = self._build_package_finder(
+            options=options,
+            session=session,
+            target_python=target_python,
+            ignore_requires_python=options.ignore_requires_python,
+        )
+        build_delete = (not (options.no_clean or options.build_dir))
+        wheel_cache = WheelCache(options.cache_dir, options.format_control)
+
+        with get_requirement_tracker() as req_tracker, TempDirectory(
+            options.build_dir, delete=build_delete, kind="install"
+        ) as directory:
+            requirement_set = RequirementSet(
+                check_supported_wheels=not options.target_dir,
+            )
+
+            try:
+                self.populate_requirement_set(
+                    requirement_set, args, options, finder, session,
+                    wheel_cache
+                )
+
+                warn_deprecated_install_options(
+                    requirement_set, options.install_options
+                )
+
+                preparer = self.make_requirement_preparer(
+                    temp_build_dir=directory,
+                    options=options,
+                    req_tracker=req_tracker,
+                    session=session,
+                    finder=finder,
+                    use_user_site=options.use_user_site,
+                )
+                resolver = self.make_resolver(
+                    preparer=preparer,
+                    finder=finder,
+                    options=options,
+                    wheel_cache=wheel_cache,
+                    use_user_site=options.use_user_site,
+                    ignore_installed=options.ignore_installed,
+                    ignore_requires_python=options.ignore_requires_python,
+                    force_reinstall=options.force_reinstall,
+                    upgrade_strategy=upgrade_strategy,
+                    use_pep517=options.use_pep517,
+                )
+
+                self.trace_basic_info(finder)
+
+                resolver.resolve(requirement_set)
+
+                try:
+                    pip_req = requirement_set.get_requirement("pip")
+                except KeyError:
+                    modifying_pip = None
+                else:
+                    # If we're not replacing an already installed pip,
+                    # we're not modifying it.
+                    modifying_pip = pip_req.satisfied_by is None
+                protect_pip_from_modification_on_windows(
+                    modifying_pip=modifying_pip
+                )
+
+                check_binary_allowed = get_check_binary_allowed(
+                    finder.format_control
+                )
+
+                reqs_to_build = [
+                    r for r in requirement_set.requirements.values()
+                    if should_build_for_install_command(
+                        r, check_binary_allowed
+                    )
+                ]
+
+                _, build_failures = build(
+                    reqs_to_build,
+                    wheel_cache=wheel_cache,
+                    build_options=[],
+                    global_options=[],
+                )
+
+                # If we're using PEP 517, we cannot do a direct install
+                # so we fail here.
+                # We don't care about failures building legacy
+                # requirements, as we'll fall through to a direct
+                # install for those.
+                pep517_build_failures = [
+                    r for r in build_failures if r.use_pep517
+                ]
+                if pep517_build_failures:
+                    raise InstallationError(
+                        "Could not build wheels for {} which use"
+                        " PEP 517 and cannot be installed directly".format(
+                            ", ".join(r.name for r in pep517_build_failures)))
+
+                to_install = resolver.get_installation_order(
+                    requirement_set
+                )
+
+                # Consistency Checking of the package set we're installing.
+                should_warn_about_conflicts = (
+                    not options.ignore_dependencies and
+                    options.warn_about_conflicts
+                )
+                if should_warn_about_conflicts:
+                    self._warn_about_conflicts(to_install)
+
+                # Don't warn about script install locations if
+                # --target has been specified
+                warn_script_location = options.warn_script_location
+                if options.target_dir:
+                    warn_script_location = False
+
+                installed = install_given_reqs(
+                    to_install,
+                    install_options,
+                    global_options,
+                    root=options.root_path,
+                    home=target_temp_dir_path,
+                    prefix=options.prefix_path,
+                    pycompile=options.compile,
+                    warn_script_location=warn_script_location,
+                    use_user_site=options.use_user_site,
+                )
+
+                lib_locations = get_lib_location_guesses(
+                    user=options.use_user_site,
+                    home=target_temp_dir_path,
+                    root=options.root_path,
+                    prefix=options.prefix_path,
+                    isolated=options.isolated_mode,
+                )
+                working_set = pkg_resources.WorkingSet(lib_locations)
+
+                installed.sort(key=operator.attrgetter('name'))
+                items = []
+                for result in installed:
+                    item = result.name
+                    try:
+                        installed_version = get_installed_version(
+                            result.name, working_set=working_set
+                        )
+                        if installed_version:
+                            item += '-' + installed_version
+                    except Exception:
+                        pass
+                    items.append(item)
+                installed_desc = ' '.join(items)
+                if installed_desc:
+                    write_output(
+                        'Successfully installed %s', installed_desc,
+                    )
+            except EnvironmentError as error:
+                show_traceback = (self.verbosity >= 1)
+
+                message = create_env_error_message(
+                    error, show_traceback, options.use_user_site,
+                )
+                logger.error(message, exc_info=show_traceback)
+
+                return ERROR
+            except PreviousBuildDirError:
+                options.no_clean = True
+                raise
+            finally:
+                # Clean up
+                if not options.no_clean:
+                    requirement_set.cleanup_files()
+                    wheel_cache.cleanup()
+
+        if options.target_dir:
+            self._handle_target_dir(
+                options.target_dir, target_temp_dir, options.upgrade
+            )
+
+        return SUCCESS
+
+    def _handle_target_dir(self, target_dir, target_temp_dir, upgrade):
+        ensure_dir(target_dir)
+
+        # Checking both purelib and platlib directories for installed
+        # packages to be moved to target directory
+        lib_dir_list = []
+
+        with target_temp_dir:
+            # Checking both purelib and platlib directories for installed
+            # packages to be moved to target directory
+            scheme = distutils_scheme('', home=target_temp_dir.path)
+            purelib_dir = scheme['purelib']
+            platlib_dir = scheme['platlib']
+            data_dir = scheme['data']
+
+            if os.path.exists(purelib_dir):
+                lib_dir_list.append(purelib_dir)
+            if os.path.exists(platlib_dir) and platlib_dir != purelib_dir:
+                lib_dir_list.append(platlib_dir)
+            if os.path.exists(data_dir):
+                lib_dir_list.append(data_dir)
+
+            for lib_dir in lib_dir_list:
+                for item in os.listdir(lib_dir):
+                    if lib_dir == data_dir:
+                        ddir = os.path.join(data_dir, item)
+                        if any(s.startswith(ddir) for s in lib_dir_list[:-1]):
+                            continue
+                    target_item_dir = os.path.join(target_dir, item)
+                    if os.path.exists(target_item_dir):
+                        if not upgrade:
+                            logger.warning(
+                                'Target directory %s already exists. Specify '
+                                '--upgrade to force replacement.',
+                                target_item_dir
+                            )
+                            continue
+                        if os.path.islink(target_item_dir):
+                            logger.warning(
+                                'Target directory %s already exists and is '
+                                'a link. Pip will not automatically replace '
+                                'links, please remove if replacement is '
+                                'desired.',
+                                target_item_dir
+                            )
+                            continue
+                        if os.path.isdir(target_item_dir):
+                            shutil.rmtree(target_item_dir)
+                        else:
+                            os.remove(target_item_dir)
+
+                    shutil.move(
+                        os.path.join(lib_dir, item),
+                        target_item_dir
+                    )
+
+    def _warn_about_conflicts(self, to_install):
+        try:
+            package_set, _dep_info = check_install_conflicts(to_install)
+        except Exception:
+            logger.error("Error checking for conflicts.", exc_info=True)
+            return
+        missing, conflicting = _dep_info
+
+        # NOTE: There is some duplication here from pip check
+        for project_name in missing:
+            version = package_set[project_name][0]
+            for dependency in missing[project_name]:
+                logger.critical(
+                    "%s %s requires %s, which is not installed.",
+                    project_name, version, dependency[1],
+                )
+
+        for project_name in conflicting:
+            version = package_set[project_name][0]
+            for dep_name, dep_version, req in conflicting[project_name]:
+                logger.critical(
+                    "%s %s has requirement %s, but you'll have %s %s which is "
+                    "incompatible.",
+                    project_name, version, req, dep_name, dep_version,
+                )
+
+
+def get_lib_location_guesses(*args, **kwargs):
+    scheme = distutils_scheme('', *args, **kwargs)
+    return [scheme['purelib'], scheme['platlib']]
+
+
+def site_packages_writable(**kwargs):
+    return all(
+        test_writable_dir(d) for d in set(get_lib_location_guesses(**kwargs))
+    )
+
+
+def decide_user_install(
+    use_user_site,  # type: Optional[bool]
+    prefix_path=None,  # type: Optional[str]
+    target_dir=None,  # type: Optional[str]
+    root_path=None,  # type: Optional[str]
+    isolated_mode=False,  # type: bool
+):
+    # type: (...) -> bool
+    """Determine whether to do a user install based on the input options.
+
+    If use_user_site is False, no additional checks are done.
+    If use_user_site is True, it is checked for compatibility with other
+    options.
+    If use_user_site is None, the default behaviour depends on the environment,
+    which is provided by the other arguments.
+    """
+    # In some cases (config from tox), use_user_site can be set to an integer
+    # rather than a bool, which 'use_user_site is False' wouldn't catch.
+    if (use_user_site is not None) and (not use_user_site):
+        logger.debug("Non-user install by explicit request")
+        return False
+
+    if use_user_site:
+        if prefix_path:
+            raise CommandError(
+                "Can not combine '--user' and '--prefix' as they imply "
+                "different installation locations"
+            )
+        if virtualenv_no_global():
+            raise InstallationError(
+                "Can not perform a '--user' install. User site-packages "
+                "are not visible in this virtualenv."
+            )
+        logger.debug("User install by explicit request")
+        return True
+
+    # If we are here, user installs have not been explicitly requested/avoided
+    assert use_user_site is None
+
+    # user install incompatible with --prefix/--target
+    if prefix_path or target_dir:
+        logger.debug("Non-user install due to --prefix or --target option")
+        return False
+
+    # If user installs are not enabled, choose a non-user install
+    if not site.ENABLE_USER_SITE:
+        logger.debug("Non-user install because user site-packages disabled")
+        return False
+
+    # If we have permission for a non-user install, do that,
+    # otherwise do a user install.
+    if site_packages_writable(root=root_path, isolated=isolated_mode):
+        logger.debug("Non-user install because site-packages writeable")
+        return False
+
+    logger.info("Defaulting to user installation because normal site-packages "
+                "is not writeable")
+    return True
+
+
+def warn_deprecated_install_options(requirement_set, options):
+    # type: (RequirementSet, Optional[List[str]]) -> None
+    """If any location-changing --install-option arguments were passed for
+    requirements or on the command-line, then show a deprecation warning.
+    """
+    def format_options(option_names):
+        # type: (Iterable[str]) -> List[str]
+        return ["--{}".format(name.replace("_", "-")) for name in option_names]
+
+    requirements = (
+        requirement_set.unnamed_requirements +
+        list(requirement_set.requirements.values())
+    )
+
+    offenders = []
+
+    for requirement in requirements:
+        install_options = requirement.options.get("install_options", [])
+        location_options = parse_distutils_args(install_options)
+        if location_options:
+            offenders.append(
+                "{!r} from {}".format(
+                    format_options(location_options.keys()), requirement
+                )
+            )
+
+    if options:
+        location_options = parse_distutils_args(options)
+        if location_options:
+            offenders.append(
+                "{!r} from command line".format(
+                    format_options(location_options.keys())
+                )
+            )
+
+    if not offenders:
+        return
+
+    deprecated(
+        reason=(
+            "Location-changing options found in --install-option: {}. "
+            "This configuration may cause unexpected behavior and is "
+            "unsupported.".format(
+                "; ".join(offenders)
+            )
+        ),
+        replacement=(
+            "using pip-level options like --user, --prefix, --root, and "
+            "--target"
+        ),
+        gone_in="20.2",
+        issue=7309,
+    )
+
+
+def create_env_error_message(error, show_traceback, using_user_site):
+    """Format an error message for an EnvironmentError
+
+    It may occur anytime during the execution of the install command.
+    """
+    parts = []
+
+    # Mention the error if we are not going to show a traceback
+    parts.append("Could not install packages due to an EnvironmentError")
+    if not show_traceback:
+        parts.append(": ")
+        parts.append(str(error))
+    else:
+        parts.append(".")
+
+    # Spilt the error indication from a helper message (if any)
+    parts[-1] += "\n"
+
+    # Suggest useful actions to the user:
+    #  (1) using user site-packages or (2) verifying the permissions
+    if error.errno == errno.EACCES:
+        user_option_part = "Consider using the `--user` option"
+        permissions_part = "Check the permissions"
+
+        if not using_user_site:
+            parts.extend([
+                user_option_part, " or ",
+                permissions_part.lower(),
+            ])
+        else:
+            parts.append(permissions_part)
+        parts.append(".\n")
+
+    return "".join(parts).strip() + "\n"

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/list.py

@@ -0,0 +1,315 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import json
+import logging
+
+from pip._vendor import six
+from pip._vendor.six.moves import zip_longest
+
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.req_command import IndexGroupCommand
+from pip._internal.exceptions import CommandError
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.models.selection_prefs import SelectionPreferences
+from pip._internal.self_outdated_check import make_link_collector
+from pip._internal.utils.misc import (
+    dist_is_editable,
+    get_installed_distributions,
+    write_output,
+)
+from pip._internal.utils.packaging import get_installer
+
+from pip._vendor.packaging.version import parse
+
+logger = logging.getLogger(__name__)
+
+
+class ListCommand(IndexGroupCommand):
+    """
+    List installed packages, including editables.
+
+    Packages are listed in a case-insensitive sorted order.
+    """
+
+    usage = """
+      %prog [options]"""
+
+    def __init__(self, *args, **kw):
+        super(ListCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(
+            '-o', '--outdated',
+            action='store_true',
+            default=False,
+            help='List outdated packages')
+        cmd_opts.add_option(
+            '-u', '--uptodate',
+            action='store_true',
+            default=False,
+            help='List uptodate packages')
+        cmd_opts.add_option(
+            '-e', '--editable',
+            action='store_true',
+            default=False,
+            help='List editable projects.')
+        cmd_opts.add_option(
+            '-l', '--local',
+            action='store_true',
+            default=False,
+            help=('If in a virtualenv that has global access, do not list '
+                  'globally-installed packages.'),
+        )
+        self.cmd_opts.add_option(
+            '--user',
+            dest='user',
+            action='store_true',
+            default=False,
+            help='Only output packages installed in user-site.')
+        cmd_opts.add_option(cmdoptions.list_path())
+        cmd_opts.add_option(
+            '--pre',
+            action='store_true',
+            default=False,
+            help=("Include pre-release and development versions. By default, "
+                  "pip only finds stable versions."),
+        )
+
+        cmd_opts.add_option(
+            '--format',
+            action='store',
+            dest='list_format',
+            default="columns",
+            choices=('columns', 'freeze', 'json'),
+            help="Select the output format among: columns (default), freeze, "
+                 "or json",
+        )
+
+        cmd_opts.add_option(
+            '--not-required',
+            action='store_true',
+            dest='not_required',
+            help="List packages that are not dependencies of "
+                 "installed packages.",
+        )
+
+        cmd_opts.add_option(
+            '--exclude-editable',
+            action='store_false',
+            dest='include_editable',
+            help='Exclude editable package from output.',
+        )
+        cmd_opts.add_option(
+            '--include-editable',
+            action='store_true',
+            dest='include_editable',
+            help='Include editable package from output.',
+            default=True,
+        )
+        index_opts = cmdoptions.make_option_group(
+            cmdoptions.index_group, self.parser
+        )
+
+        self.parser.insert_option_group(0, index_opts)
+        self.parser.insert_option_group(0, cmd_opts)
+
+    def _build_package_finder(self, options, session):
+        """
+        Create a package finder appropriate to this list command.
+        """
+        link_collector = make_link_collector(session, options=options)
+
+        # Pass allow_yanked=False to ignore yanked versions.
+        selection_prefs = SelectionPreferences(
+            allow_yanked=False,
+            allow_all_prereleases=options.pre,
+        )
+
+        return PackageFinder.create(
+            link_collector=link_collector,
+            selection_prefs=selection_prefs,
+        )
+
+    def run(self, options, args):
+        if options.outdated and options.uptodate:
+            raise CommandError(
+                "Options --outdated and --uptodate cannot be combined.")
+
+        cmdoptions.check_list_path_option(options)
+
+        packages = get_installed_distributions(
+            local_only=options.local,
+            user_only=options.user,
+            editables_only=options.editable,
+            include_editables=options.include_editable,
+            paths=options.path,
+        )
+
+        # get_not_required must be called firstly in order to find and
+        # filter out all dependencies correctly. Otherwise a package
+        # can't be identified as requirement because some parent packages
+        # could be filtered out before.
+        if options.not_required:
+            packages = self.get_not_required(packages, options)
+
+        if options.outdated:
+            packages = self.get_outdated(packages, options)
+        elif options.uptodate:
+            packages = self.get_uptodate(packages, options)
+
+        self.output_package_listing(packages, options)
+
+    def get_outdated(self, packages, options):
+        return [
+            dist for dist in self.iter_packages_latest_infos(packages, options)
+            if parse(str(dist.latest_version)) > parse(str(dist.parsed_version))
+        ]
+
+    def get_uptodate(self, packages, options):
+        return [
+            dist for dist in self.iter_packages_latest_infos(packages, options)
+            if parse(str(dist.latest_version)) == parse(str(dist.parsed_version))
+        ]
+
+    def get_not_required(self, packages, options):
+        dep_keys = set()
+        for dist in packages:
+            dep_keys.update(requirement.key for requirement in dist.requires())
+        return {pkg for pkg in packages if pkg.key not in dep_keys}
+
+    def iter_packages_latest_infos(self, packages, options):
+        with self._build_session(options) as session:
+            finder = self._build_package_finder(options, session)
+
+            for dist in packages:
+                typ = 'unknown'
+                all_candidates = finder.find_all_candidates(dist.key)
+                if not options.pre:
+                    # Remove prereleases
+                    all_candidates = [candidate for candidate in all_candidates
+                                      if not candidate.version.is_prerelease]
+
+                evaluator = finder.make_candidate_evaluator(
+                    project_name=dist.project_name,
+                )
+                best_candidate = evaluator.sort_best_candidate(all_candidates)
+                if best_candidate is None:
+                    continue
+
+                remote_version = best_candidate.version
+                if best_candidate.link.is_wheel:
+                    typ = 'wheel'
+                else:
+                    typ = 'sdist'
+                # This is dirty but makes the rest of the code much cleaner
+                dist.latest_version = remote_version
+                dist.latest_filetype = typ
+                yield dist
+
+    def output_package_listing(self, packages, options):
+        packages = sorted(
+            packages,
+            key=lambda dist: dist.project_name.lower(),
+        )
+        if options.list_format == 'columns' and packages:
+            data, header = format_for_columns(packages, options)
+            self.output_package_listing_columns(data, header)
+        elif options.list_format == 'freeze':
+            for dist in packages:
+                if options.verbose >= 1:
+                    write_output("%s==%s (%s)", dist.project_name,
+                                 dist.version, dist.location)
+                else:
+                    write_output("%s==%s", dist.project_name, dist.version)
+        elif options.list_format == 'json':
+            write_output(format_for_json(packages, options))
+
+    def output_package_listing_columns(self, data, header):
+        # insert the header first: we need to know the size of column names
+        if len(data) > 0:
+            data.insert(0, header)
+
+        pkg_strings, sizes = tabulate(data)
+
+        # Create and add a separator.
+        if len(data) > 0:
+            pkg_strings.insert(1, " ".join(map(lambda x: '-' * x, sizes)))
+
+        for val in pkg_strings:
+            write_output(val)
+
+
+def tabulate(vals):
+    # From pfmoore on GitHub:
+    # https://github.com/pypa/pip/issues/3651#issuecomment-216932564
+    assert len(vals) > 0
+
+    sizes = [0] * max(len(x) for x in vals)
+    for row in vals:
+        sizes = [max(s, len(str(c))) for s, c in zip_longest(sizes, row)]
+
+    result = []
+    for row in vals:
+        display = " ".join([str(c).ljust(s) if c is not None else ''
+                            for s, c in zip_longest(sizes, row)])
+        result.append(display)
+
+    return result, sizes
+
+
+def format_for_columns(pkgs, options):
+    """
+    Convert the package data into something usable
+    by output_package_listing_columns.
+    """
+    running_outdated = options.outdated
+    # Adjust the header for the `pip list --outdated` case.
+    if running_outdated:
+        header = ["Package", "Version", "Latest", "Type"]
+    else:
+        header = ["Package", "Version"]
+
+    data = []
+    if options.verbose >= 1 or any(dist_is_editable(x) for x in pkgs):
+        header.append("Location")
+    if options.verbose >= 1:
+        header.append("Installer")
+
+    for proj in pkgs:
+        # if we're working on the 'outdated' list, separate out the
+        # latest_version and type
+        row = [proj.project_name, proj.version]
+
+        if running_outdated:
+            row.append(proj.latest_version)
+            row.append(proj.latest_filetype)
+
+        if options.verbose >= 1 or dist_is_editable(proj):
+            row.append(proj.location)
+        if options.verbose >= 1:
+            row.append(get_installer(proj))
+
+        data.append(row)
+
+    return data, header
+
+
+def format_for_json(packages, options):
+    data = []
+    for dist in packages:
+        info = {
+            'name': dist.project_name,
+            'version': six.text_type(dist.version),
+        }
+        if options.verbose >= 1:
+            info['location'] = dist.location
+            info['installer'] = get_installer(dist)
+        if options.outdated:
+            info['latest_version'] = six.text_type(dist.latest_version)
+            info['latest_filetype'] = dist.latest_filetype
+        data.append(info)
+    return json.dumps(data)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/search.py

@@ -0,0 +1,145 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import sys
+import textwrap
+from collections import OrderedDict
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging.version import parse as parse_version
+# NOTE: XMLRPC Client is not annotated in typeshed as on 2017-07-17, which is
+#       why we ignore the type on this import
+from pip._vendor.six.moves import xmlrpc_client  # type: ignore
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.req_command import SessionCommandMixin
+from pip._internal.cli.status_codes import NO_MATCHES_FOUND, SUCCESS
+from pip._internal.exceptions import CommandError
+from pip._internal.models.index import PyPI
+from pip._internal.network.xmlrpc import PipXmlrpcTransport
+from pip._internal.utils.compat import get_terminal_size
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import write_output
+
+logger = logging.getLogger(__name__)
+
+
+class SearchCommand(Command, SessionCommandMixin):
+    """Search for PyPI packages whose name or summary contains <query>."""
+
+    usage = """
+      %prog [options] <query>"""
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(SearchCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-i', '--index',
+            dest='index',
+            metavar='URL',
+            default=PyPI.pypi_url,
+            help='Base URL of Python Package Index (default %default)')
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        if not args:
+            raise CommandError('Missing required argument (search query).')
+        query = args
+        pypi_hits = self.search(query, options)
+        hits = transform_hits(pypi_hits)
+
+        terminal_width = None
+        if sys.stdout.isatty():
+            terminal_width = get_terminal_size()[0]
+
+        print_results(hits, terminal_width=terminal_width)
+        if pypi_hits:
+            return SUCCESS
+        return NO_MATCHES_FOUND
+
+    def search(self, query, options):
+        index_url = options.index
+
+        session = self.get_default_session(options)
+
+        transport = PipXmlrpcTransport(index_url, session)
+        pypi = xmlrpc_client.ServerProxy(index_url, transport)
+        hits = pypi.search({'name': query, 'summary': query}, 'or')
+        return hits
+
+
+def transform_hits(hits):
+    """
+    The list from pypi is really a list of versions. We want a list of
+    packages with the list of versions stored inline. This converts the
+    list from pypi into one we can use.
+    """
+    packages = OrderedDict()
+    for hit in hits:
+        name = hit['name']
+        summary = hit['summary']
+        version = hit['version']
+
+        if name not in packages.keys():
+            packages[name] = {
+                'name': name,
+                'summary': summary,
+                'versions': [version],
+            }
+        else:
+            packages[name]['versions'].append(version)
+
+            # if this is the highest version, replace summary and score
+            if version == highest_version(packages[name]['versions']):
+                packages[name]['summary'] = summary
+
+    return list(packages.values())
+
+
+def print_results(hits, name_column_width=None, terminal_width=None):
+    if not hits:
+        return
+    if name_column_width is None:
+        name_column_width = max([
+            len(hit['name']) + len(highest_version(hit.get('versions', ['-'])))
+            for hit in hits
+        ]) + 4
+
+    installed_packages = [p.project_name for p in pkg_resources.working_set]
+    for hit in hits:
+        name = hit['name']
+        summary = hit['summary'] or ''
+        latest = highest_version(hit.get('versions', ['-']))
+        if terminal_width is not None:
+            target_width = terminal_width - name_column_width - 5
+            if target_width > 10:
+                # wrap and indent summary to fit terminal
+                summary = textwrap.wrap(summary, target_width)
+                summary = ('\n' + ' ' * (name_column_width + 3)).join(summary)
+
+        line = '%-*s - %s' % (name_column_width,
+                              '%s (%s)' % (name, latest), summary)
+        try:
+            write_output(line)
+            if name in installed_packages:
+                dist = pkg_resources.get_distribution(name)
+                with indent_log():
+                    if dist.version == latest:
+                        write_output('INSTALLED: %s (latest)', dist.version)
+                    else:
+                        write_output('INSTALLED: %s', dist.version)
+                        if parse_version(latest).pre:
+                            write_output('LATEST:    %s (pre-release; install'
+                                         ' with "pip install --pre")', latest)
+                        else:
+                            write_output('LATEST:    %s', latest)
+        except UnicodeEncodeError:
+            pass
+
+
+def highest_version(versions):
+    return max(versions, key=parse_version)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/show.py

@@ -0,0 +1,180 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+from email.parser import FeedParser
+
+from pip._vendor import pkg_resources
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.utils.misc import write_output
+
+logger = logging.getLogger(__name__)
+
+
+class ShowCommand(Command):
+    """
+    Show information about one or more installed packages.
+
+    The output is in RFC-compliant mail header format.
+    """
+
+    usage = """
+      %prog [options] <package> ..."""
+    ignore_require_venv = True
+
+    def __init__(self, *args, **kw):
+        super(ShowCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-f', '--files',
+            dest='files',
+            action='store_true',
+            default=False,
+            help='Show the full list of installed files for each package.')
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        if not args:
+            logger.warning('ERROR: Please provide a package name or names.')
+            return ERROR
+        query = args
+
+        results = search_packages_info(query)
+        if not print_results(
+                results, list_files=options.files, verbose=options.verbose):
+            return ERROR
+        return SUCCESS
+
+
+def search_packages_info(query):
+    """
+    Gather details from installed distributions. Print distribution name,
+    version, location, and installed files. Installed files requires a
+    pip generated 'installed-files.txt' in the distributions '.egg-info'
+    directory.
+    """
+    installed = {}
+    for p in pkg_resources.working_set:
+        installed[canonicalize_name(p.project_name)] = p
+
+    query_names = [canonicalize_name(name) for name in query]
+    missing = sorted(
+        [name for name, pkg in zip(query, query_names) if pkg not in installed]
+    )
+    if missing:
+        logger.warning('Package(s) not found: %s', ', '.join(missing))
+
+    def get_requiring_packages(package_name):
+        canonical_name = canonicalize_name(package_name)
+        return [
+            pkg.project_name for pkg in pkg_resources.working_set
+            if canonical_name in
+               [canonicalize_name(required.name) for required in
+                pkg.requires()]
+        ]
+
+    for dist in [installed[pkg] for pkg in query_names if pkg in installed]:
+        package = {
+            'name': dist.project_name,
+            'version': dist.version,
+            'location': dist.location,
+            'requires': [dep.project_name for dep in dist.requires()],
+            'required_by': get_requiring_packages(dist.project_name)
+        }
+        file_list = None
+        metadata = None
+        if isinstance(dist, pkg_resources.DistInfoDistribution):
+            # RECORDs should be part of .dist-info metadatas
+            if dist.has_metadata('RECORD'):
+                lines = dist.get_metadata_lines('RECORD')
+                paths = [l.split(',')[0] for l in lines]
+                paths = [os.path.join(dist.location, p) for p in paths]
+                file_list = [os.path.relpath(p, dist.location) for p in paths]
+
+            if dist.has_metadata('METADATA'):
+                metadata = dist.get_metadata('METADATA')
+        else:
+            # Otherwise use pip's log for .egg-info's
+            if dist.has_metadata('installed-files.txt'):
+                paths = dist.get_metadata_lines('installed-files.txt')
+                paths = [os.path.join(dist.egg_info, p) for p in paths]
+                file_list = [os.path.relpath(p, dist.location) for p in paths]
+
+            if dist.has_metadata('PKG-INFO'):
+                metadata = dist.get_metadata('PKG-INFO')
+
+        if dist.has_metadata('entry_points.txt'):
+            entry_points = dist.get_metadata_lines('entry_points.txt')
+            package['entry_points'] = entry_points
+
+        if dist.has_metadata('INSTALLER'):
+            for line in dist.get_metadata_lines('INSTALLER'):
+                if line.strip():
+                    package['installer'] = line.strip()
+                    break
+
+        # @todo: Should pkg_resources.Distribution have a
+        # `get_pkg_info` method?
+        feed_parser = FeedParser()
+        feed_parser.feed(metadata)
+        pkg_info_dict = feed_parser.close()
+        for key in ('metadata-version', 'summary',
+                    'home-page', 'author', 'author-email', 'license'):
+            package[key] = pkg_info_dict.get(key)
+
+        # It looks like FeedParser cannot deal with repeated headers
+        classifiers = []
+        for line in metadata.splitlines():
+            if line.startswith('Classifier: '):
+                classifiers.append(line[len('Classifier: '):])
+        package['classifiers'] = classifiers
+
+        if file_list:
+            package['files'] = sorted(file_list)
+        yield package
+
+
+def print_results(distributions, list_files=False, verbose=False):
+    """
+    Print the informations from installed distributions found.
+    """
+    results_printed = False
+    for i, dist in enumerate(distributions):
+        results_printed = True
+        if i > 0:
+            write_output("---")
+
+        write_output("Name: %s", dist.get('name', ''))
+        write_output("Version: %s", dist.get('version', ''))
+        write_output("Summary: %s", dist.get('summary', ''))
+        write_output("Home-page: %s", dist.get('home-page', ''))
+        write_output("Author: %s", dist.get('author', ''))
+        write_output("Author-email: %s", dist.get('author-email', ''))
+        write_output("License: %s", dist.get('license', ''))
+        write_output("Location: %s", dist.get('location', ''))
+        write_output("Requires: %s", ', '.join(dist.get('requires', [])))
+        write_output("Required-by: %s", ', '.join(dist.get('required_by', [])))
+
+        if verbose:
+            write_output("Metadata-Version: %s",
+                         dist.get('metadata-version', ''))
+            write_output("Installer: %s", dist.get('installer', ''))
+            write_output("Classifiers:")
+            for classifier in dist.get('classifiers', []):
+                write_output("  %s", classifier)
+            write_output("Entry-points:")
+            for entry in dist.get('entry_points', []):
+                write_output("  %s", entry.strip())
+        if list_files:
+            write_output("Files:")
+            for line in dist.get('files', []):
+                write_output("  %s", line.strip())
+            if "files" not in dist:
+                write_output("Cannot locate installed-files.txt")
+    return results_printed

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/uninstall.py

@@ -0,0 +1,82 @@
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.cli.base_command import Command
+from pip._internal.cli.req_command import SessionCommandMixin
+from pip._internal.exceptions import InstallationError
+from pip._internal.req import parse_requirements
+from pip._internal.req.constructors import install_req_from_line
+from pip._internal.utils.misc import protect_pip_from_modification_on_windows
+
+
+class UninstallCommand(Command, SessionCommandMixin):
+    """
+    Uninstall packages.
+
+    pip is able to uninstall most installed packages. Known exceptions are:
+
+    - Pure distutils packages installed with ``python setup.py install``, which
+      leave behind no metadata to determine what files were installed.
+    - Script wrappers installed by ``python setup.py develop``.
+    """
+
+    usage = """
+      %prog [options] <package> ...
+      %prog [options] -r <requirements file> ..."""
+
+    def __init__(self, *args, **kw):
+        super(UninstallCommand, self).__init__(*args, **kw)
+        self.cmd_opts.add_option(
+            '-r', '--requirement',
+            dest='requirements',
+            action='append',
+            default=[],
+            metavar='file',
+            help='Uninstall all the packages listed in the given requirements '
+                 'file.  This option can be used multiple times.',
+        )
+        self.cmd_opts.add_option(
+            '-y', '--yes',
+            dest='yes',
+            action='store_true',
+            help="Don't ask for confirmation of uninstall deletions.")
+
+        self.parser.insert_option_group(0, self.cmd_opts)
+
+    def run(self, options, args):
+        session = self.get_default_session(options)
+
+        reqs_to_uninstall = {}
+        for name in args:
+            req = install_req_from_line(
+                name, isolated=options.isolated_mode,
+            )
+            if req.name:
+                reqs_to_uninstall[canonicalize_name(req.name)] = req
+        for filename in options.requirements:
+            for req in parse_requirements(
+                    filename,
+                    options=options,
+                    session=session):
+                if req.name:
+                    reqs_to_uninstall[canonicalize_name(req.name)] = req
+        if not reqs_to_uninstall:
+            raise InstallationError(
+                'You must give at least one requirement to %(name)s (see '
+                '"pip help %(name)s")' % dict(name=self.name)
+            )
+
+        protect_pip_from_modification_on_windows(
+            modifying_pip="pip" in reqs_to_uninstall
+        )
+
+        for req in reqs_to_uninstall.values():
+            uninstall_pathset = req.uninstall(
+                auto_confirm=options.yes, verbose=self.verbosity > 0,
+            )
+            if uninstall_pathset:
+                uninstall_pathset.commit()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/commands/wheel.py

@@ -0,0 +1,197 @@
+# -*- coding: utf-8 -*-
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+import shutil
+
+from pip._internal.cache import WheelCache
+from pip._internal.cli import cmdoptions
+from pip._internal.cli.req_command import RequirementCommand
+from pip._internal.exceptions import CommandError, PreviousBuildDirError
+from pip._internal.req import RequirementSet
+from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.misc import ensure_dir, normalize_path
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.wheel_builder import build, should_build_for_wheel_command
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import Any, List
+
+
+logger = logging.getLogger(__name__)
+
+
+class WheelCommand(RequirementCommand):
+    """
+    Build Wheel archives for your requirements and dependencies.
+
+    Wheel is a built-package format, and offers the advantage of not
+    recompiling your software during every install. For more details, see the
+    wheel docs: https://wheel.readthedocs.io/en/latest/
+
+    Requirements: setuptools>=0.8, and wheel.
+
+    'pip wheel' uses the bdist_wheel setuptools extension from the wheel
+    package to build individual wheels.
+
+    """
+
+    usage = """
+      %prog [options] <requirement specifier> ...
+      %prog [options] -r <requirements file> ...
+      %prog [options] [-e] <vcs project url> ...
+      %prog [options] [-e] <local project path> ...
+      %prog [options] <archive url/path> ..."""
+
+    def __init__(self, *args, **kw):
+        super(WheelCommand, self).__init__(*args, **kw)
+
+        cmd_opts = self.cmd_opts
+
+        cmd_opts.add_option(
+            '-w', '--wheel-dir',
+            dest='wheel_dir',
+            metavar='dir',
+            default=os.curdir,
+            help=("Build wheels into <dir>, where the default is the "
+                  "current working directory."),
+        )
+        cmd_opts.add_option(cmdoptions.no_binary())
+        cmd_opts.add_option(cmdoptions.only_binary())
+        cmd_opts.add_option(cmdoptions.prefer_binary())
+        cmd_opts.add_option(
+            '--build-option',
+            dest='build_options',
+            metavar='options',
+            action='append',
+            help="Extra arguments to be supplied to 'setup.py bdist_wheel'.",
+        )
+        cmd_opts.add_option(cmdoptions.no_build_isolation())
+        cmd_opts.add_option(cmdoptions.use_pep517())
+        cmd_opts.add_option(cmdoptions.no_use_pep517())
+        cmd_opts.add_option(cmdoptions.constraints())
+        cmd_opts.add_option(cmdoptions.editable())
+        cmd_opts.add_option(cmdoptions.requirements())
+        cmd_opts.add_option(cmdoptions.src())
+        cmd_opts.add_option(cmdoptions.ignore_requires_python())
+        cmd_opts.add_option(cmdoptions.no_deps())
+        cmd_opts.add_option(cmdoptions.build_dir())
+        cmd_opts.add_option(cmdoptions.progress_bar())
+
+        cmd_opts.add_option(
+            '--global-option',
+            dest='global_options',
+            action='append',
+            metavar='options',
+            help="Extra global options to be supplied to the setup.py "
+            "call before the 'bdist_wheel' command.")
+
+        cmd_opts.add_option(
+            '--pre',
+            action='store_true',
+            default=False,
+            help=("Include pre-release and development versions. By default, "
+                  "pip only finds stable versions."),
+        )
+
+        cmd_opts.add_option(cmdoptions.no_clean())
+        cmd_opts.add_option(cmdoptions.require_hashes())
+
+        index_opts = cmdoptions.make_option_group(
+            cmdoptions.index_group,
+            self.parser,
+        )
+
+        self.parser.insert_option_group(0, index_opts)
+        self.parser.insert_option_group(0, cmd_opts)
+
+    def run(self, options, args):
+        # type: (Values, List[Any]) -> None
+        cmdoptions.check_install_build_global(options)
+
+        session = self.get_default_session(options)
+
+        finder = self._build_package_finder(options, session)
+        build_delete = (not (options.no_clean or options.build_dir))
+        wheel_cache = WheelCache(options.cache_dir, options.format_control)
+
+        options.wheel_dir = normalize_path(options.wheel_dir)
+        ensure_dir(options.wheel_dir)
+
+        with get_requirement_tracker() as req_tracker, TempDirectory(
+            options.build_dir, delete=build_delete, kind="wheel"
+        ) as directory:
+
+            requirement_set = RequirementSet()
+
+            try:
+                self.populate_requirement_set(
+                    requirement_set, args, options, finder, session,
+                    wheel_cache
+                )
+
+                preparer = self.make_requirement_preparer(
+                    temp_build_dir=directory,
+                    options=options,
+                    req_tracker=req_tracker,
+                    session=session,
+                    finder=finder,
+                    wheel_download_dir=options.wheel_dir,
+                    use_user_site=False,
+                )
+
+                resolver = self.make_resolver(
+                    preparer=preparer,
+                    finder=finder,
+                    options=options,
+                    wheel_cache=wheel_cache,
+                    ignore_requires_python=options.ignore_requires_python,
+                    use_pep517=options.use_pep517,
+                )
+
+                self.trace_basic_info(finder)
+
+                resolver.resolve(requirement_set)
+
+                reqs_to_build = [
+                    r for r in requirement_set.requirements.values()
+                    if should_build_for_wheel_command(r)
+                ]
+
+                # build wheels
+                build_successes, build_failures = build(
+                    reqs_to_build,
+                    wheel_cache=wheel_cache,
+                    build_options=options.build_options or [],
+                    global_options=options.global_options or [],
+                )
+                for req in build_successes:
+                    assert req.link and req.link.is_wheel
+                    assert req.local_file_path
+                    # copy from cache to target directory
+                    try:
+                        shutil.copy(req.local_file_path, options.wheel_dir)
+                    except OSError as e:
+                        logger.warning(
+                            "Building wheel for %s failed: %s",
+                            req.name, e,
+                        )
+                        build_failures.append(req)
+                if len(build_failures) != 0:
+                    raise CommandError(
+                        "Failed to build one or more wheels"
+                    )
+            except PreviousBuildDirError:
+                options.no_clean = True
+                raise
+            finally:
+                if not options.no_clean:
+                    requirement_set.cleanup_files()
+                    wheel_cache.cleanup()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/configuration.py

@@ -0,0 +1,422 @@
+"""Configuration management setup
+
+Some terminology:
+- name
+  As written in config files.
+- value
+  Value associated with a name
+- key
+  Name combined with it's section (section.name)
+- variant
+  A single word describing where the configuration key-value pair came from
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import locale
+import logging
+import os
+import sys
+
+from pip._vendor.six.moves import configparser
+
+from pip._internal.exceptions import (
+    ConfigurationError,
+    ConfigurationFileCouldNotBeLoaded,
+)
+from pip._internal.utils import appdirs
+from pip._internal.utils.compat import WINDOWS, expanduser
+from pip._internal.utils.misc import ensure_dir, enum
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, Dict, Iterable, List, NewType, Optional, Tuple
+    )
+
+    RawConfigParser = configparser.RawConfigParser  # Shorthand
+    Kind = NewType("Kind", str)
+
+logger = logging.getLogger(__name__)
+
+
+# NOTE: Maybe use the optionx attribute to normalize keynames.
+def _normalize_name(name):
+    # type: (str) -> str
+    """Make a name consistent regardless of source (environment or file)
+    """
+    name = name.lower().replace('_', '-')
+    if name.startswith('--'):
+        name = name[2:]  # only prefer long opts
+    return name
+
+
+def _disassemble_key(name):
+    # type: (str) -> List[str]
+    if "." not in name:
+        error_message = (
+            "Key does not contain dot separated section and key. "
+            "Perhaps you wanted to use 'global.{}' instead?"
+        ).format(name)
+        raise ConfigurationError(error_message)
+    return name.split(".", 1)
+
+
+# The kinds of configurations there are.
+kinds = enum(
+    USER="user",        # User Specific
+    GLOBAL="global",    # System Wide
+    SITE="site",        # [Virtual] Environment Specific
+    ENV="env",          # from PIP_CONFIG_FILE
+    ENV_VAR="env-var",  # from Environment Variables
+)
+
+
+CONFIG_BASENAME = 'pip.ini' if WINDOWS else 'pip.conf'
+
+
+def get_configuration_files():
+    # type: () -> Dict[Kind, List[str]]
+    global_config_files = [
+        os.path.join(path, CONFIG_BASENAME)
+        for path in appdirs.site_config_dirs('pip')
+    ]
+
+    site_config_file = os.path.join(sys.prefix, CONFIG_BASENAME)
+    legacy_config_file = os.path.join(
+        expanduser('~'),
+        'pip' if WINDOWS else '.pip',
+        CONFIG_BASENAME,
+    )
+    new_config_file = os.path.join(
+        appdirs.user_config_dir("pip"), CONFIG_BASENAME
+    )
+    return {
+        kinds.GLOBAL: global_config_files,
+        kinds.SITE: [site_config_file],
+        kinds.USER: [legacy_config_file, new_config_file],
+    }
+
+
+class Configuration(object):
+    """Handles management of configuration.
+
+    Provides an interface to accessing and managing configuration files.
+
+    This class converts provides an API that takes "section.key-name" style
+    keys and stores the value associated with it as "key-name" under the
+    section "section".
+
+    This allows for a clean interface wherein the both the section and the
+    key-name are preserved in an easy to manage form in the configuration files
+    and the data stored is also nice.
+    """
+
+    def __init__(self, isolated, load_only=None):
+        # type: (bool, Kind) -> None
+        super(Configuration, self).__init__()
+
+        _valid_load_only = [kinds.USER, kinds.GLOBAL, kinds.SITE, None]
+        if load_only not in _valid_load_only:
+            raise ConfigurationError(
+                "Got invalid value for load_only - should be one of {}".format(
+                    ", ".join(map(repr, _valid_load_only[:-1]))
+                )
+            )
+        self.isolated = isolated  # type: bool
+        self.load_only = load_only  # type: Optional[Kind]
+
+        # The order here determines the override order.
+        self._override_order = [
+            kinds.GLOBAL, kinds.USER, kinds.SITE, kinds.ENV, kinds.ENV_VAR
+        ]
+
+        self._ignore_env_names = ["version", "help"]
+
+        # Because we keep track of where we got the data from
+        self._parsers = {
+            variant: [] for variant in self._override_order
+        }  # type: Dict[Kind, List[Tuple[str, RawConfigParser]]]
+        self._config = {
+            variant: {} for variant in self._override_order
+        }  # type: Dict[Kind, Dict[str, Any]]
+        self._modified_parsers = []  # type: List[Tuple[str, RawConfigParser]]
+
+    def load(self):
+        # type: () -> None
+        """Loads configuration from configuration files and environment
+        """
+        self._load_config_files()
+        if not self.isolated:
+            self._load_environment_vars()
+
+    def get_file_to_edit(self):
+        # type: () -> Optional[str]
+        """Returns the file with highest priority in configuration
+        """
+        assert self.load_only is not None, \
+            "Need to be specified a file to be editing"
+
+        try:
+            return self._get_parser_to_modify()[0]
+        except IndexError:
+            return None
+
+    def items(self):
+        # type: () -> Iterable[Tuple[str, Any]]
+        """Returns key-value pairs like dict.items() representing the loaded
+        configuration
+        """
+        return self._dictionary.items()
+
+    def get_value(self, key):
+        # type: (str) -> Any
+        """Get a value from the configuration.
+        """
+        try:
+            return self._dictionary[key]
+        except KeyError:
+            raise ConfigurationError("No such key - {}".format(key))
+
+    def set_value(self, key, value):
+        # type: (str, Any) -> None
+        """Modify a value in the configuration.
+        """
+        self._ensure_have_load_only()
+
+        fname, parser = self._get_parser_to_modify()
+
+        if parser is not None:
+            section, name = _disassemble_key(key)
+
+            # Modify the parser and the configuration
+            if not parser.has_section(section):
+                parser.add_section(section)
+            parser.set(section, name, value)
+
+        self._config[self.load_only][key] = value
+        self._mark_as_modified(fname, parser)
+
+    def unset_value(self, key):
+        # type: (str) -> None
+        """Unset a value in the configuration.
+        """
+        self._ensure_have_load_only()
+
+        if key not in self._config[self.load_only]:
+            raise ConfigurationError("No such key - {}".format(key))
+
+        fname, parser = self._get_parser_to_modify()
+
+        if parser is not None:
+            section, name = _disassemble_key(key)
+
+            # Remove the key in the parser
+            modified_something = False
+            if parser.has_section(section):
+                # Returns whether the option was removed or not
+                modified_something = parser.remove_option(section, name)
+
+            if modified_something:
+                # name removed from parser, section may now be empty
+                section_iter = iter(parser.items(section))
+                try:
+                    val = next(section_iter)
+                except StopIteration:
+                    val = None
+
+                if val is None:
+                    parser.remove_section(section)
+
+                self._mark_as_modified(fname, parser)
+            else:
+                raise ConfigurationError(
+                    "Fatal Internal error [id=1]. Please report as a bug."
+                )
+
+        del self._config[self.load_only][key]
+
+    def save(self):
+        # type: () -> None
+        """Save the current in-memory state.
+        """
+        self._ensure_have_load_only()
+
+        for fname, parser in self._modified_parsers:
+            logger.info("Writing to %s", fname)
+
+            # Ensure directory exists.
+            ensure_dir(os.path.dirname(fname))
+
+            with open(fname, "w") as f:
+                parser.write(f)
+
+    #
+    # Private routines
+    #
+
+    def _ensure_have_load_only(self):
+        # type: () -> None
+        if self.load_only is None:
+            raise ConfigurationError("Needed a specific file to be modifying.")
+        logger.debug("Will be working with %s variant only", self.load_only)
+
+    @property
+    def _dictionary(self):
+        # type: () -> Dict[str, Any]
+        """A dictionary representing the loaded configuration.
+        """
+        # NOTE: Dictionaries are not populated if not loaded. So, conditionals
+        #       are not needed here.
+        retval = {}
+
+        for variant in self._override_order:
+            retval.update(self._config[variant])
+
+        return retval
+
+    def _load_config_files(self):
+        # type: () -> None
+        """Loads configuration from configuration files
+        """
+        config_files = dict(self._iter_config_files())
+        if config_files[kinds.ENV][0:1] == [os.devnull]:
+            logger.debug(
+                "Skipping loading configuration files due to "
+                "environment's PIP_CONFIG_FILE being os.devnull"
+            )
+            return
+
+        for variant, files in config_files.items():
+            for fname in files:
+                # If there's specific variant set in `load_only`, load only
+                # that variant, not the others.
+                if self.load_only is not None and variant != self.load_only:
+                    logger.debug(
+                        "Skipping file '%s' (variant: %s)", fname, variant
+                    )
+                    continue
+
+                parser = self._load_file(variant, fname)
+
+                # Keeping track of the parsers used
+                self._parsers[variant].append((fname, parser))
+
+    def _load_file(self, variant, fname):
+        # type: (Kind, str) -> RawConfigParser
+        logger.debug("For variant '%s', will try loading '%s'", variant, fname)
+        parser = self._construct_parser(fname)
+
+        for section in parser.sections():
+            items = parser.items(section)
+            self._config[variant].update(self._normalized_keys(section, items))
+
+        return parser
+
+    def _construct_parser(self, fname):
+        # type: (str) -> RawConfigParser
+        parser = configparser.RawConfigParser()
+        # If there is no such file, don't bother reading it but create the
+        # parser anyway, to hold the data.
+        # Doing this is useful when modifying and saving files, where we don't
+        # need to construct a parser.
+        if os.path.exists(fname):
+            try:
+                parser.read(fname)
+            except UnicodeDecodeError:
+                # See https://github.com/pypa/pip/issues/4963
+                raise ConfigurationFileCouldNotBeLoaded(
+                    reason="contains invalid {} characters".format(
+                        locale.getpreferredencoding(False)
+                    ),
+                    fname=fname,
+                )
+            except configparser.Error as error:
+                # See https://github.com/pypa/pip/issues/4893
+                raise ConfigurationFileCouldNotBeLoaded(error=error)
+        return parser
+
+    def _load_environment_vars(self):
+        # type: () -> None
+        """Loads configuration from environment variables
+        """
+        self._config[kinds.ENV_VAR].update(
+            self._normalized_keys(":env:", self._get_environ_vars())
+        )
+
+    def _normalized_keys(self, section, items):
+        # type: (str, Iterable[Tuple[str, Any]]) -> Dict[str, Any]
+        """Normalizes items to construct a dictionary with normalized keys.
+
+        This routine is where the names become keys and are made the same
+        regardless of source - configuration files or environment.
+        """
+        normalized = {}
+        for name, val in items:
+            key = section + "." + _normalize_name(name)
+            normalized[key] = val
+        return normalized
+
+    def _get_environ_vars(self):
+        # type: () -> Iterable[Tuple[str, str]]
+        """Returns a generator with all environmental vars with prefix PIP_"""
+        for key, val in os.environ.items():
+            should_be_yielded = (
+                key.startswith("PIP_") and
+                key[4:].lower() not in self._ignore_env_names
+            )
+            if should_be_yielded:
+                yield key[4:].lower(), val
+
+    # XXX: This is patched in the tests.
+    def _iter_config_files(self):
+        # type: () -> Iterable[Tuple[Kind, List[str]]]
+        """Yields variant and configuration files associated with it.
+
+        This should be treated like items of a dictionary.
+        """
+        # SMELL: Move the conditions out of this function
+
+        # environment variables have the lowest priority
+        config_file = os.environ.get('PIP_CONFIG_FILE', None)
+        if config_file is not None:
+            yield kinds.ENV, [config_file]
+        else:
+            yield kinds.ENV, []
+
+        config_files = get_configuration_files()
+
+        # at the base we have any global configuration
+        yield kinds.GLOBAL, config_files[kinds.GLOBAL]
+
+        # per-user configuration next
+        should_load_user_config = not self.isolated and not (
+            config_file and os.path.exists(config_file)
+        )
+        if should_load_user_config:
+            # The legacy config file is overridden by the new config file
+            yield kinds.USER, config_files[kinds.USER]
+
+        # finally virtualenv configuration first trumping others
+        yield kinds.SITE, config_files[kinds.SITE]
+
+    def _get_parser_to_modify(self):
+        # type: () -> Tuple[str, RawConfigParser]
+        # Determine which parser to modify
+        parsers = self._parsers[self.load_only]
+        if not parsers:
+            # This should not happen if everything works correctly.
+            raise ConfigurationError(
+                "Fatal Internal error [id=2]. Please report as a bug."
+            )
+
+        # Use the highest priority parser.
+        return parsers[-1]
+
+    # XXX: This is patched in the tests.
+    def _mark_as_modified(self, fname, parser):
+        # type: (str, RawConfigParser) -> None
+        file_parser_tuple = (fname, parser)
+        if file_parser_tuple not in self._modified_parsers:
+            self._modified_parsers.append(file_parser_tuple)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/distributions/__init__.py

@@ -0,0 +1,24 @@
+from pip._internal.distributions.sdist import SourceDistribution
+from pip._internal.distributions.wheel import WheelDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from pip._internal.distributions.base import AbstractDistribution
+    from pip._internal.req.req_install import InstallRequirement
+
+
+def make_distribution_for_install_requirement(install_req):
+    # type: (InstallRequirement) -> AbstractDistribution
+    """Returns a Distribution for the given InstallRequirement
+    """
+    # Editable requirements will always be source distributions. They use the
+    # legacy logic until we create a modern standard for them.
+    if install_req.editable:
+        return SourceDistribution(install_req)
+
+    # If it's a wheel, it's a WheelDistribution
+    if install_req.is_wheel:
+        return WheelDistribution(install_req)
+
+    # Otherwise, a SourceDistribution
+    return SourceDistribution(install_req)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/distributions/base.py

@@ -0,0 +1,45 @@
+import abc
+
+from pip._vendor.six import add_metaclass
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.req import InstallRequirement
+    from pip._internal.index.package_finder import PackageFinder
+
+
+@add_metaclass(abc.ABCMeta)
+class AbstractDistribution(object):
+    """A base class for handling installable artifacts.
+
+    The requirements for anything installable are as follows:
+
+     - we must be able to determine the requirement name
+       (or we can't correctly handle the non-upgrade case).
+
+     - for packages with setup requirements, we must also be able
+       to determine their requirements without installing additional
+       packages (for the same reason as run-time dependencies)
+
+     - we must be able to create a Distribution object exposing the
+       above metadata.
+    """
+
+    def __init__(self, req):
+        # type: (InstallRequirement) -> None
+        super(AbstractDistribution, self).__init__()
+        self.req = req
+
+    @abc.abstractmethod
+    def get_pkg_resources_distribution(self):
+        # type: () -> Optional[Distribution]
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        raise NotImplementedError()

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/distributions/installed.py

@@ -0,0 +1,24 @@
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+class InstalledDistribution(AbstractDistribution):
+    """Represents an installed package.
+
+    This does not need any preparation as the required information has already
+    been computed.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Optional[Distribution]
+        return self.req.satisfied_by
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        pass

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/distributions/sdist.py

@@ -0,0 +1,104 @@
+import logging
+
+from pip._internal.build_env import BuildEnvironment
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.exceptions import InstallationError
+from pip._internal.utils.subprocess import runner_with_spinner_message
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Set, Tuple
+
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+logger = logging.getLogger(__name__)
+
+
+class SourceDistribution(AbstractDistribution):
+    """Represents a source distribution.
+
+    The preparation step for these needs metadata for the packages to be
+    generated, either using PEP 517 or using the legacy `setup.py egg_info`.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Distribution
+        return self.req.get_dist()
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        # Load pyproject.toml, to determine whether PEP 517 is to be used
+        self.req.load_pyproject_toml()
+
+        # Set up the build isolation, if this requirement should be isolated
+        should_isolate = self.req.use_pep517 and build_isolation
+        if should_isolate:
+            self._setup_isolation(finder)
+
+        self.req.prepare_metadata()
+
+    def _setup_isolation(self, finder):
+        # type: (PackageFinder) -> None
+        def _raise_conflicts(conflicting_with, conflicting_reqs):
+            # type: (str, Set[Tuple[str, str]]) -> None
+            format_string = (
+                "Some build dependencies for {requirement} "
+                "conflict with {conflicting_with}: {description}."
+            )
+            error_message = format_string.format(
+                requirement=self.req,
+                conflicting_with=conflicting_with,
+                description=', '.join(
+                    '{} is incompatible with {}'.format(installed, wanted)
+                    for installed, wanted in sorted(conflicting)
+                )
+            )
+            raise InstallationError(error_message)
+
+        # Isolate in a BuildEnvironment and install the build-time
+        # requirements.
+        pyproject_requires = self.req.pyproject_requires
+        assert pyproject_requires is not None
+
+        self.req.build_env = BuildEnvironment()
+        self.req.build_env.install_requirements(
+            finder, pyproject_requires, 'overlay',
+            "Installing build dependencies"
+        )
+        conflicting, missing = self.req.build_env.check_requirements(
+            self.req.requirements_to_check
+        )
+        if conflicting:
+            _raise_conflicts("PEP 517/518 supported requirements",
+                             conflicting)
+        if missing:
+            logger.warning(
+                "Missing build requirements in pyproject.toml for %s.",
+                self.req,
+            )
+            logger.warning(
+                "The project does not specify a build backend, and "
+                "pip cannot fall back to setuptools without %s.",
+                " and ".join(map(repr, sorted(missing)))
+            )
+        # Install any extra build dependencies that the backend requests.
+        # This must be done in a second pass, as the pyproject.toml
+        # dependencies must be installed before we can call the backend.
+        with self.req.build_env:
+            runner = runner_with_spinner_message(
+                "Getting requirements to build wheel"
+            )
+            backend = self.req.pep517_backend
+            assert backend is not None
+            with backend.subprocess_runner(runner):
+                reqs = backend.get_requires_for_build_wheel()
+
+        conflicting, missing = self.req.build_env.check_requirements(reqs)
+        if conflicting:
+            _raise_conflicts("the backend dependencies", conflicting)
+        self.req.build_env.install_requirements(
+            finder, missing, 'normal',
+            "Installing backend dependencies"
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/distributions/wheel.py

@@ -0,0 +1,36 @@
+from zipfile import ZipFile
+
+from pip._internal.distributions.base import AbstractDistribution
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.wheel import pkg_resources_distribution_for_wheel
+
+if MYPY_CHECK_RUNNING:
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.index.package_finder import PackageFinder
+
+
+class WheelDistribution(AbstractDistribution):
+    """Represents a wheel distribution.
+
+    This does not need any preparation as wheels can be directly unpacked.
+    """
+
+    def get_pkg_resources_distribution(self):
+        # type: () -> Distribution
+        """Loads the metadata from the wheel file into memory and returns a
+        Distribution that uses it, not relying on the wheel file or
+        requirement.
+        """
+        # Set as part of preparation during download.
+        assert self.req.local_file_path
+        # Wheels are never unnamed.
+        assert self.req.name
+
+        with ZipFile(self.req.local_file_path, allowZip64=True) as z:
+            return pkg_resources_distribution_for_wheel(
+                z, self.req.name, self.req.local_file_path
+            )
+
+    def prepare_distribution_metadata(self, finder, build_isolation):
+        # type: (PackageFinder, bool) -> None
+        pass

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/exceptions.py

@@ -0,0 +1,308 @@
+"""Exceptions used throughout package"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+from itertools import chain, groupby, repeat
+
+from pip._vendor.six import iteritems
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+    from pip._vendor.pkg_resources import Distribution
+    from pip._internal.req.req_install import InstallRequirement
+
+
+class PipError(Exception):
+    """Base pip exception"""
+
+
+class ConfigurationError(PipError):
+    """General exception in configuration"""
+
+
+class InstallationError(PipError):
+    """General exception during installation"""
+
+
+class UninstallationError(PipError):
+    """General exception during uninstallation"""
+
+
+class NoneMetadataError(PipError):
+    """
+    Raised when accessing "METADATA" or "PKG-INFO" metadata for a
+    pip._vendor.pkg_resources.Distribution object and
+    `dist.has_metadata('METADATA')` returns True but
+    `dist.get_metadata('METADATA')` returns None (and similarly for
+    "PKG-INFO").
+    """
+
+    def __init__(self, dist, metadata_name):
+        # type: (Distribution, str) -> None
+        """
+        :param dist: A Distribution object.
+        :param metadata_name: The name of the metadata being accessed
+            (can be "METADATA" or "PKG-INFO").
+        """
+        self.dist = dist
+        self.metadata_name = metadata_name
+
+    def __str__(self):
+        # type: () -> str
+        # Use `dist` in the error message because its stringification
+        # includes more information, like the version and location.
+        return (
+            'None {} metadata found for distribution: {}'.format(
+                self.metadata_name, self.dist,
+            )
+        )
+
+
+class DistributionNotFound(InstallationError):
+    """Raised when a distribution cannot be found to satisfy a requirement"""
+
+
+class RequirementsFileParseError(InstallationError):
+    """Raised when a general error occurs parsing a requirements file line."""
+
+
+class BestVersionAlreadyInstalled(PipError):
+    """Raised when the most up-to-date version of a package is already
+    installed."""
+
+
+class BadCommand(PipError):
+    """Raised when virtualenv or a command is not found"""
+
+
+class CommandError(PipError):
+    """Raised when there is an error in command-line arguments"""
+
+
+class PreviousBuildDirError(PipError):
+    """Raised when there's a previous conflicting build directory"""
+
+
+class InvalidWheelFilename(InstallationError):
+    """Invalid wheel filename."""
+
+
+class UnsupportedWheel(InstallationError):
+    """Unsupported wheel."""
+
+
+class HashErrors(InstallationError):
+    """Multiple HashError instances rolled into one for reporting"""
+
+    def __init__(self):
+        self.errors = []
+
+    def append(self, error):
+        self.errors.append(error)
+
+    def __str__(self):
+        lines = []
+        self.errors.sort(key=lambda e: e.order)
+        for cls, errors_of_cls in groupby(self.errors, lambda e: e.__class__):
+            lines.append(cls.head)
+            lines.extend(e.body() for e in errors_of_cls)
+        if lines:
+            return '\n'.join(lines)
+
+    def __nonzero__(self):
+        return bool(self.errors)
+
+    def __bool__(self):
+        return self.__nonzero__()
+
+
+class HashError(InstallationError):
+    """
+    A failure to verify a package against known-good hashes
+
+    :cvar order: An int sorting hash exception classes by difficulty of
+        recovery (lower being harder), so the user doesn't bother fretting
+        about unpinned packages when he has deeper issues, like VCS
+        dependencies, to deal with. Also keeps error reports in a
+        deterministic order.
+    :cvar head: A section heading for display above potentially many
+        exceptions of this kind
+    :ivar req: The InstallRequirement that triggered this error. This is
+        pasted on after the exception is instantiated, because it's not
+        typically available earlier.
+
+    """
+    req = None  # type: Optional[InstallRequirement]
+    head = ''
+
+    def body(self):
+        """Return a summary of me for display under the heading.
+
+        This default implementation simply prints a description of the
+        triggering requirement.
+
+        :param req: The InstallRequirement that provoked this error, with
+            populate_link() having already been called
+
+        """
+        return '    %s' % self._requirement_name()
+
+    def __str__(self):
+        return '%s\n%s' % (self.head, self.body())
+
+    def _requirement_name(self):
+        """Return a description of the requirement that triggered me.
+
+        This default implementation returns long description of the req, with
+        line numbers
+
+        """
+        return str(self.req) if self.req else 'unknown package'
+
+
+class VcsHashUnsupported(HashError):
+    """A hash was provided for a version-control-system-based requirement, but
+    we don't have a method for hashing those."""
+
+    order = 0
+    head = ("Can't verify hashes for these requirements because we don't "
+            "have a way to hash version control repositories:")
+
+
+class DirectoryUrlHashUnsupported(HashError):
+    """A hash was provided for a version-control-system-based requirement, but
+    we don't have a method for hashing those."""
+
+    order = 1
+    head = ("Can't verify hashes for these file:// requirements because they "
+            "point to directories:")
+
+
+class HashMissing(HashError):
+    """A hash was needed for a requirement but is absent."""
+
+    order = 2
+    head = ('Hashes are required in --require-hashes mode, but they are '
+            'missing from some requirements. Here is a list of those '
+            'requirements along with the hashes their downloaded archives '
+            'actually had. Add lines like these to your requirements files to '
+            'prevent tampering. (If you did not enable --require-hashes '
+            'manually, note that it turns on automatically when any package '
+            'has a hash.)')
+
+    def __init__(self, gotten_hash):
+        """
+        :param gotten_hash: The hash of the (possibly malicious) archive we
+            just downloaded
+        """
+        self.gotten_hash = gotten_hash
+
+    def body(self):
+        # Dodge circular import.
+        from pip._internal.utils.hashes import FAVORITE_HASH
+
+        package = None
+        if self.req:
+            # In the case of URL-based requirements, display the original URL
+            # seen in the requirements file rather than the package name,
+            # so the output can be directly copied into the requirements file.
+            package = (self.req.original_link if self.req.original_link
+                       # In case someone feeds something downright stupid
+                       # to InstallRequirement's constructor.
+                       else getattr(self.req, 'req', None))
+        return '    %s --hash=%s:%s' % (package or 'unknown package',
+                                        FAVORITE_HASH,
+                                        self.gotten_hash)
+
+
+class HashUnpinned(HashError):
+    """A requirement had a hash specified but was not pinned to a specific
+    version."""
+
+    order = 3
+    head = ('In --require-hashes mode, all requirements must have their '
+            'versions pinned with ==. These do not:')
+
+
+class HashMismatch(HashError):
+    """
+    Distribution file hash values don't match.
+
+    :ivar package_name: The name of the package that triggered the hash
+        mismatch. Feel free to write to this after the exception is raise to
+        improve its error message.
+
+    """
+    order = 4
+    head = ('THESE PACKAGES DO NOT MATCH THE HASHES FROM THE REQUIREMENTS '
+            'FILE. If you have updated the package versions, please update '
+            'the hashes. Otherwise, examine the package contents carefully; '
+            'someone may have tampered with them.')
+
+    def __init__(self, allowed, gots):
+        """
+        :param allowed: A dict of algorithm names pointing to lists of allowed
+            hex digests
+        :param gots: A dict of algorithm names pointing to hashes we
+            actually got from the files under suspicion
+        """
+        self.allowed = allowed
+        self.gots = gots
+
+    def body(self):
+        return '    %s:\n%s' % (self._requirement_name(),
+                                self._hash_comparison())
+
+    def _hash_comparison(self):
+        """
+        Return a comparison of actual and expected hash values.
+
+        Example::
+
+               Expected sha256 abcdeabcdeabcdeabcdeabcdeabcdeabcdeabcdeabcde
+                            or 123451234512345123451234512345123451234512345
+                    Got        bcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdefbcdef
+
+        """
+        def hash_then_or(hash_name):
+            # For now, all the decent hashes have 6-char names, so we can get
+            # away with hard-coding space literals.
+            return chain([hash_name], repeat('    or'))
+
+        lines = []
+        for hash_name, expecteds in iteritems(self.allowed):
+            prefix = hash_then_or(hash_name)
+            lines.extend(('        Expected %s %s' % (next(prefix), e))
+                         for e in expecteds)
+            lines.append('             Got        %s\n' %
+                         self.gots[hash_name].hexdigest())
+        return '\n'.join(lines)
+
+
+class UnsupportedPythonVersion(InstallationError):
+    """Unsupported python version according to Requires-Python package
+    metadata."""
+
+
+class ConfigurationFileCouldNotBeLoaded(ConfigurationError):
+    """When there are errors while loading a configuration file
+    """
+
+    def __init__(self, reason="could not be loaded", fname=None, error=None):
+        super(ConfigurationFileCouldNotBeLoaded, self).__init__(error)
+        self.reason = reason
+        self.fname = fname
+        self.error = error
+
+    def __str__(self):
+        if self.fname is not None:
+            message_part = " in {}.".format(self.fname)
+        else:
+            assert self.error is not None
+            message_part = ".\n{}\n".format(self.error.message)
+        return "Configuration file {}{}".format(self.reason, message_part)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/index/__init__.py

@@ -0,0 +1,2 @@
+"""Index interaction code
+"""

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/index/collector.py

@@ -0,0 +1,544 @@
+"""
+The main purpose of this module is to expose LinkCollector.collect_links().
+"""
+
+import cgi
+import itertools
+import logging
+import mimetypes
+import os
+from collections import OrderedDict
+
+from pip._vendor import html5lib, requests
+from pip._vendor.distlib.compat import unescape
+from pip._vendor.requests.exceptions import HTTPError, RetryError, SSLError
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.six.moves.urllib import request as urllib_request
+
+from pip._internal.models.link import Link
+from pip._internal.utils.filetypes import ARCHIVE_EXTENSIONS
+from pip._internal.utils.misc import redact_auth_from_url
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url, url_to_path
+from pip._internal.vcs import is_url, vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Callable, Iterable, List, MutableMapping, Optional, Sequence, Tuple,
+        Union,
+    )
+    import xml.etree.ElementTree
+
+    from pip._vendor.requests import Response
+
+    from pip._internal.models.search_scope import SearchScope
+    from pip._internal.network.session import PipSession
+
+    HTMLElement = xml.etree.ElementTree.Element
+    ResponseHeaders = MutableMapping[str, str]
+
+
+logger = logging.getLogger(__name__)
+
+
+def _match_vcs_scheme(url):
+    # type: (str) -> Optional[str]
+    """Look for VCS schemes in the URL.
+
+    Returns the matched VCS scheme, or None if there's no match.
+    """
+    for scheme in vcs.schemes:
+        if url.lower().startswith(scheme) and url[len(scheme)] in '+:':
+            return scheme
+    return None
+
+
+def _is_url_like_archive(url):
+    # type: (str) -> bool
+    """Return whether the URL looks like an archive.
+    """
+    filename = Link(url).filename
+    for bad_ext in ARCHIVE_EXTENSIONS:
+        if filename.endswith(bad_ext):
+            return True
+    return False
+
+
+class _NotHTML(Exception):
+    def __init__(self, content_type, request_desc):
+        # type: (str, str) -> None
+        super(_NotHTML, self).__init__(content_type, request_desc)
+        self.content_type = content_type
+        self.request_desc = request_desc
+
+
+def _ensure_html_header(response):
+    # type: (Response) -> None
+    """Check the Content-Type header to ensure the response contains HTML.
+
+    Raises `_NotHTML` if the content type is not text/html.
+    """
+    content_type = response.headers.get("Content-Type", "")
+    if not content_type.lower().startswith("text/html"):
+        raise _NotHTML(content_type, response.request.method)
+
+
+class _NotHTTP(Exception):
+    pass
+
+
+def _ensure_html_response(url, session):
+    # type: (str, PipSession) -> None
+    """Send a HEAD request to the URL, and ensure the response contains HTML.
+
+    Raises `_NotHTTP` if the URL is not available for a HEAD request, or
+    `_NotHTML` if the content type is not text/html.
+    """
+    scheme, netloc, path, query, fragment = urllib_parse.urlsplit(url)
+    if scheme not in {'http', 'https'}:
+        raise _NotHTTP()
+
+    resp = session.head(url, allow_redirects=True)
+    resp.raise_for_status()
+
+    _ensure_html_header(resp)
+
+
+def _get_html_response(url, session):
+    # type: (str, PipSession) -> Response
+    """Access an HTML page with GET, and return the response.
+
+    This consists of three parts:
+
+    1. If the URL looks suspiciously like an archive, send a HEAD first to
+       check the Content-Type is HTML, to avoid downloading a large file.
+       Raise `_NotHTTP` if the content type cannot be determined, or
+       `_NotHTML` if it is not HTML.
+    2. Actually perform the request. Raise HTTP exceptions on network failures.
+    3. Check the Content-Type header to make sure we got HTML, and raise
+       `_NotHTML` otherwise.
+    """
+    if _is_url_like_archive(url):
+        _ensure_html_response(url, session=session)
+
+    logger.debug('Getting page %s', redact_auth_from_url(url))
+
+    resp = session.get(
+        url,
+        headers={
+            "Accept": "text/html",
+            # We don't want to blindly returned cached data for
+            # /simple/, because authors generally expecting that
+            # twine upload && pip install will function, but if
+            # they've done a pip install in the last ~10 minutes
+            # it won't. Thus by setting this to zero we will not
+            # blindly use any cached data, however the benefit of
+            # using max-age=0 instead of no-cache, is that we will
+            # still support conditional requests, so we will still
+            # minimize traffic sent in cases where the page hasn't
+            # changed at all, we will just always incur the round
+            # trip for the conditional GET now instead of only
+            # once per 10 minutes.
+            # For more information, please see pypa/pip#5670.
+            "Cache-Control": "max-age=0",
+        },
+    )
+    resp.raise_for_status()
+
+    # The check for archives above only works if the url ends with
+    # something that looks like an archive. However that is not a
+    # requirement of an url. Unless we issue a HEAD request on every
+    # url we cannot know ahead of time for sure if something is HTML
+    # or not. However we can check after we've downloaded it.
+    _ensure_html_header(resp)
+
+    return resp
+
+
+def _get_encoding_from_headers(headers):
+    # type: (ResponseHeaders) -> Optional[str]
+    """Determine if we have any encoding information in our headers.
+    """
+    if headers and "Content-Type" in headers:
+        content_type, params = cgi.parse_header(headers["Content-Type"])
+        if "charset" in params:
+            return params['charset']
+    return None
+
+
+def _determine_base_url(document, page_url):
+    # type: (HTMLElement, str) -> str
+    """Determine the HTML document's base URL.
+
+    This looks for a ``<base>`` tag in the HTML document. If present, its href
+    attribute denotes the base URL of anchor tags in the document. If there is
+    no such tag (or if it does not have a valid href attribute), the HTML
+    file's URL is used as the base URL.
+
+    :param document: An HTML document representation. The current
+        implementation expects the result of ``html5lib.parse()``.
+    :param page_url: The URL of the HTML document.
+    """
+    for base in document.findall(".//base"):
+        href = base.get("href")
+        if href is not None:
+            return href
+    return page_url
+
+
+def _clean_link(url):
+    # type: (str) -> str
+    """Makes sure a link is fully encoded.  That is, if a ' ' shows up in
+    the link, it will be rewritten to %20 (while not over-quoting
+    % or other characters)."""
+    # Split the URL into parts according to the general structure
+    # `scheme://netloc/path;parameters?query#fragment`. Note that the
+    # `netloc` can be empty and the URI will then refer to a local
+    # filesystem path.
+    result = urllib_parse.urlparse(url)
+    # In both cases below we unquote prior to quoting to make sure
+    # nothing is double quoted.
+    if result.netloc == "":
+        # On Windows the path part might contain a drive letter which
+        # should not be quoted. On Linux where drive letters do not
+        # exist, the colon should be quoted. We rely on urllib.request
+        # to do the right thing here.
+        path = urllib_request.pathname2url(
+            urllib_request.url2pathname(result.path))
+    else:
+        # In addition to the `/` character we protect `@` so that
+        # revision strings in VCS URLs are properly parsed.
+        path = urllib_parse.quote(urllib_parse.unquote(result.path), safe="/@")
+    return urllib_parse.urlunparse(result._replace(path=path))
+
+
+def _create_link_from_element(
+    anchor,    # type: HTMLElement
+    page_url,  # type: str
+    base_url,  # type: str
+):
+    # type: (...) -> Optional[Link]
+    """
+    Convert an anchor element in a simple repository page to a Link.
+    """
+    href = anchor.get("href")
+    if not href:
+        return None
+
+    url = _clean_link(urllib_parse.urljoin(base_url, href))
+    pyrequire = anchor.get('data-requires-python')
+    pyrequire = unescape(pyrequire) if pyrequire else None
+
+    yanked_reason = anchor.get('data-yanked')
+    if yanked_reason:
+        # This is a unicode string in Python 2 (and 3).
+        yanked_reason = unescape(yanked_reason)
+
+    link = Link(
+        url,
+        comes_from=page_url,
+        requires_python=pyrequire,
+        yanked_reason=yanked_reason,
+    )
+
+    return link
+
+
+def parse_links(page):
+    # type: (HTMLPage) -> Iterable[Link]
+    """
+    Parse an HTML document, and yield its anchor elements as Link objects.
+    """
+    document = html5lib.parse(
+        page.content,
+        transport_encoding=page.encoding,
+        namespaceHTMLElements=False,
+    )
+
+    url = page.url
+    base_url = _determine_base_url(document, url)
+    for anchor in document.findall(".//a"):
+        link = _create_link_from_element(
+            anchor,
+            page_url=url,
+            base_url=base_url,
+        )
+        if link is None:
+            continue
+        yield link
+
+
+class HTMLPage(object):
+    """Represents one page, along with its URL"""
+
+    def __init__(
+        self,
+        content,   # type: bytes
+        encoding,  # type: Optional[str]
+        url,       # type: str
+    ):
+        # type: (...) -> None
+        """
+        :param encoding: the encoding to decode the given content.
+        :param url: the URL from which the HTML was downloaded.
+        """
+        self.content = content
+        self.encoding = encoding
+        self.url = url
+
+    def __str__(self):
+        # type: () -> str
+        return redact_auth_from_url(self.url)
+
+
+def _handle_get_page_fail(
+    link,  # type: Link
+    reason,  # type: Union[str, Exception]
+    meth=None  # type: Optional[Callable[..., None]]
+):
+    # type: (...) -> None
+    if meth is None:
+        meth = logger.debug
+    meth("Could not fetch URL %s: %s - skipping", link, reason)
+
+
+def _make_html_page(response):
+    # type: (Response) -> HTMLPage
+    encoding = _get_encoding_from_headers(response.headers)
+    return HTMLPage(response.content, encoding=encoding, url=response.url)
+
+
+def _get_html_page(link, session=None):
+    # type: (Link, Optional[PipSession]) -> Optional[HTMLPage]
+    if session is None:
+        raise TypeError(
+            "_get_html_page() missing 1 required keyword argument: 'session'"
+        )
+
+    url = link.url.split('#', 1)[0]
+
+    # Check for VCS schemes that do not support lookup as web pages.
+    vcs_scheme = _match_vcs_scheme(url)
+    if vcs_scheme:
+        logger.debug('Cannot look at %s URL %s', vcs_scheme, link)
+        return None
+
+    # Tack index.html onto file:// URLs that point to directories
+    scheme, _, path, _, _, _ = urllib_parse.urlparse(url)
+    if (scheme == 'file' and os.path.isdir(urllib_request.url2pathname(path))):
+        # add trailing slash if not present so urljoin doesn't trim
+        # final segment
+        if not url.endswith('/'):
+            url += '/'
+        url = urllib_parse.urljoin(url, 'index.html')
+        logger.debug(' file: URL is directory, getting %s', url)
+
+    try:
+        resp = _get_html_response(url, session=session)
+    except _NotHTTP:
+        logger.debug(
+            'Skipping page %s because it looks like an archive, and cannot '
+            'be checked by HEAD.', link,
+        )
+    except _NotHTML as exc:
+        logger.debug(
+            'Skipping page %s because the %s request got Content-Type: %s',
+            link, exc.request_desc, exc.content_type,
+        )
+    except HTTPError as exc:
+        _handle_get_page_fail(link, exc)
+    except RetryError as exc:
+        _handle_get_page_fail(link, exc)
+    except SSLError as exc:
+        reason = "There was a problem confirming the ssl certificate: "
+        reason += str(exc)
+        _handle_get_page_fail(link, reason, meth=logger.info)
+    except requests.ConnectionError as exc:
+        _handle_get_page_fail(link, "connection error: %s" % exc)
+    except requests.Timeout:
+        _handle_get_page_fail(link, "timed out")
+    else:
+        return _make_html_page(resp)
+    return None
+
+
+def _remove_duplicate_links(links):
+    # type: (Iterable[Link]) -> List[Link]
+    """
+    Return a list of links, with duplicates removed and ordering preserved.
+    """
+    # We preserve the ordering when removing duplicates because we can.
+    return list(OrderedDict.fromkeys(links))
+
+
+def group_locations(locations, expand_dir=False):
+    # type: (Sequence[str], bool) -> Tuple[List[str], List[str]]
+    """
+    Divide a list of locations into two groups: "files" (archives) and "urls."
+
+    :return: A pair of lists (files, urls).
+    """
+    files = []
+    urls = []
+
+    # puts the url for the given file path into the appropriate list
+    def sort_path(path):
+        # type: (str) -> None
+        url = path_to_url(path)
+        if mimetypes.guess_type(url, strict=False)[0] == 'text/html':
+            urls.append(url)
+        else:
+            files.append(url)
+
+    for url in locations:
+
+        is_local_path = os.path.exists(url)
+        is_file_url = url.startswith('file:')
+
+        if is_local_path or is_file_url:
+            if is_local_path:
+                path = url
+            else:
+                path = url_to_path(url)
+            if os.path.isdir(path):
+                if expand_dir:
+                    path = os.path.realpath(path)
+                    for item in os.listdir(path):
+                        sort_path(os.path.join(path, item))
+                elif is_file_url:
+                    urls.append(url)
+                else:
+                    logger.warning(
+                        "Path '{0}' is ignored: "
+                        "it is a directory.".format(path),
+                    )
+            elif os.path.isfile(path):
+                sort_path(path)
+            else:
+                logger.warning(
+                    "Url '%s' is ignored: it is neither a file "
+                    "nor a directory.", url,
+                )
+        elif is_url(url):
+            # Only add url with clear scheme
+            urls.append(url)
+        else:
+            logger.warning(
+                "Url '%s' is ignored. It is either a non-existing "
+                "path or lacks a specific scheme.", url,
+            )
+
+    return files, urls
+
+
+class CollectedLinks(object):
+
+    """
+    Encapsulates the return value of a call to LinkCollector.collect_links().
+
+    The return value includes both URLs to project pages containing package
+    links, as well as individual package Link objects collected from other
+    sources.
+
+    This info is stored separately as:
+
+    (1) links from the configured file locations,
+    (2) links from the configured find_links, and
+    (3) urls to HTML project pages, as described by the PEP 503 simple
+        repository API.
+    """
+
+    def __init__(
+        self,
+        files,         # type: List[Link]
+        find_links,    # type: List[Link]
+        project_urls,  # type: List[Link]
+    ):
+        # type: (...) -> None
+        """
+        :param files: Links from file locations.
+        :param find_links: Links from find_links.
+        :param project_urls: URLs to HTML project pages, as described by
+            the PEP 503 simple repository API.
+        """
+        self.files = files
+        self.find_links = find_links
+        self.project_urls = project_urls
+
+
+class LinkCollector(object):
+
+    """
+    Responsible for collecting Link objects from all configured locations,
+    making network requests as needed.
+
+    The class's main method is its collect_links() method.
+    """
+
+    def __init__(
+        self,
+        session,       # type: PipSession
+        search_scope,  # type: SearchScope
+    ):
+        # type: (...) -> None
+        self.search_scope = search_scope
+        self.session = session
+
+    @property
+    def find_links(self):
+        # type: () -> List[str]
+        return self.search_scope.find_links
+
+    def fetch_page(self, location):
+        # type: (Link) -> Optional[HTMLPage]
+        """
+        Fetch an HTML page containing package links.
+        """
+        return _get_html_page(location, session=self.session)
+
+    def collect_links(self, project_name):
+        # type: (str) -> CollectedLinks
+        """Find all available links for the given project name.
+
+        :return: All the Link objects (unfiltered), as a CollectedLinks object.
+        """
+        search_scope = self.search_scope
+        index_locations = search_scope.get_index_urls_locations(project_name)
+        index_file_loc, index_url_loc = group_locations(index_locations)
+        fl_file_loc, fl_url_loc = group_locations(
+            self.find_links, expand_dir=True,
+        )
+
+        file_links = [
+            Link(url) for url in itertools.chain(index_file_loc, fl_file_loc)
+        ]
+
+        # We trust every directly linked archive in find_links
+        find_link_links = [Link(url, '-f') for url in self.find_links]
+
+        # We trust every url that the user has given us whether it was given
+        # via --index-url or --find-links.
+        # We want to filter out anything that does not have a secure origin.
+        url_locations = [
+            link for link in itertools.chain(
+                (Link(url) for url in index_url_loc),
+                (Link(url) for url in fl_url_loc),
+            )
+            if self.session.is_secure_origin(link)
+        ]
+
+        url_locations = _remove_duplicate_links(url_locations)
+        lines = [
+            '{} location(s) to search for versions of {}:'.format(
+                len(url_locations), project_name,
+            ),
+        ]
+        for link in url_locations:
+            lines.append('* {}'.format(link))
+        logger.debug('\n'.join(lines))
+
+        return CollectedLinks(
+            files=file_links,
+            find_links=find_link_links,
+            project_urls=url_locations,
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/legacy_resolve.py

@@ -0,0 +1,430 @@
+"""Dependency Resolution
+
+The dependency resolution in pip is performed as follows:
+
+for top-level requirements:
+    a. only one spec allowed per project, regardless of conflicts or not.
+       otherwise a "double requirement" exception is raised
+    b. they override sub-dependency requirements.
+for sub-dependencies
+    a. "first found, wins" (where the order is breadth first)
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+import logging
+import sys
+from collections import defaultdict
+from itertools import chain
+
+from pip._vendor.packaging import specifiers
+
+from pip._internal.exceptions import (
+    BestVersionAlreadyInstalled,
+    DistributionNotFound,
+    HashError,
+    HashErrors,
+    UnsupportedPythonVersion,
+)
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import dist_in_usersite, normalize_version_info
+from pip._internal.utils.packaging import (
+    check_requires_python,
+    get_requires_python,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Callable, DefaultDict, List, Optional, Set, Tuple
+    from pip._vendor import pkg_resources
+
+    from pip._internal.distributions import AbstractDistribution
+    from pip._internal.index.package_finder import PackageFinder
+    from pip._internal.operations.prepare import RequirementPreparer
+    from pip._internal.req.req_install import InstallRequirement
+    from pip._internal.req.req_set import RequirementSet
+
+    InstallRequirementProvider = Callable[
+        [str, InstallRequirement], InstallRequirement
+    ]
+    DiscoveredDependencies = DefaultDict[str, List[InstallRequirement]]
+
+logger = logging.getLogger(__name__)
+
+
+def _check_dist_requires_python(
+    dist,  # type: pkg_resources.Distribution
+    version_info,  # type: Tuple[int, int, int]
+    ignore_requires_python=False,  # type: bool
+):
+    # type: (...) -> None
+    """
+    Check whether the given Python version is compatible with a distribution's
+    "Requires-Python" value.
+
+    :param version_info: A 3-tuple of ints representing the Python
+        major-minor-micro version to check.
+    :param ignore_requires_python: Whether to ignore the "Requires-Python"
+        value if the given Python version isn't compatible.
+
+    :raises UnsupportedPythonVersion: When the given Python version isn't
+        compatible.
+    """
+    requires_python = get_requires_python(dist)
+    try:
+        is_compatible = check_requires_python(
+            requires_python, version_info=version_info,
+        )
+    except specifiers.InvalidSpecifier as exc:
+        logger.warning(
+            "Package %r has an invalid Requires-Python: %s",
+            dist.project_name, exc,
+        )
+        return
+
+    if is_compatible:
+        return
+
+    version = '.'.join(map(str, version_info))
+    if ignore_requires_python:
+        logger.debug(
+            'Ignoring failed Requires-Python check for package %r: '
+            '%s not in %r',
+            dist.project_name, version, requires_python,
+        )
+        return
+
+    raise UnsupportedPythonVersion(
+        'Package {!r} requires a different Python: {} not in {!r}'.format(
+            dist.project_name, version, requires_python,
+        ))
+
+
+class Resolver(object):
+    """Resolves which packages need to be installed/uninstalled to perform \
+    the requested operation without breaking the requirements of any package.
+    """
+
+    _allowed_strategies = {"eager", "only-if-needed", "to-satisfy-only"}
+
+    def __init__(
+        self,
+        preparer,  # type: RequirementPreparer
+        finder,  # type: PackageFinder
+        make_install_req,  # type: InstallRequirementProvider
+        use_user_site,  # type: bool
+        ignore_dependencies,  # type: bool
+        ignore_installed,  # type: bool
+        ignore_requires_python,  # type: bool
+        force_reinstall,  # type: bool
+        upgrade_strategy,  # type: str
+        py_version_info=None,  # type: Optional[Tuple[int, ...]]
+    ):
+        # type: (...) -> None
+        super(Resolver, self).__init__()
+        assert upgrade_strategy in self._allowed_strategies
+
+        if py_version_info is None:
+            py_version_info = sys.version_info[:3]
+        else:
+            py_version_info = normalize_version_info(py_version_info)
+
+        self._py_version_info = py_version_info
+
+        self.preparer = preparer
+        self.finder = finder
+
+        self.upgrade_strategy = upgrade_strategy
+        self.force_reinstall = force_reinstall
+        self.ignore_dependencies = ignore_dependencies
+        self.ignore_installed = ignore_installed
+        self.ignore_requires_python = ignore_requires_python
+        self.use_user_site = use_user_site
+        self._make_install_req = make_install_req
+
+        self._discovered_dependencies = \
+            defaultdict(list)  # type: DiscoveredDependencies
+
+    def resolve(self, requirement_set):
+        # type: (RequirementSet) -> None
+        """Resolve what operations need to be done
+
+        As a side-effect of this method, the packages (and their dependencies)
+        are downloaded, unpacked and prepared for installation. This
+        preparation is done by ``pip.operations.prepare``.
+
+        Once PyPI has static dependency metadata available, it would be
+        possible to move the preparation to become a step separated from
+        dependency resolution.
+        """
+        # If any top-level requirement has a hash specified, enter
+        # hash-checking mode, which requires hashes from all.
+        root_reqs = (
+            requirement_set.unnamed_requirements +
+            list(requirement_set.requirements.values())
+        )
+
+        # Actually prepare the files, and collect any exceptions. Most hash
+        # exceptions cannot be checked ahead of time, because
+        # req.populate_link() needs to be called before we can make decisions
+        # based on link type.
+        discovered_reqs = []  # type: List[InstallRequirement]
+        hash_errors = HashErrors()
+        for req in chain(root_reqs, discovered_reqs):
+            try:
+                discovered_reqs.extend(self._resolve_one(requirement_set, req))
+            except HashError as exc:
+                exc.req = req
+                hash_errors.append(exc)
+
+        if hash_errors:
+            raise hash_errors
+
+    def _is_upgrade_allowed(self, req):
+        # type: (InstallRequirement) -> bool
+        if self.upgrade_strategy == "to-satisfy-only":
+            return False
+        elif self.upgrade_strategy == "eager":
+            return True
+        else:
+            assert self.upgrade_strategy == "only-if-needed"
+            return req.is_direct
+
+    def _set_req_to_reinstall(self, req):
+        # type: (InstallRequirement) -> None
+        """
+        Set a requirement to be installed.
+        """
+        # Don't uninstall the conflict if doing a user install and the
+        # conflict is not a user install.
+        if not self.use_user_site or dist_in_usersite(req.satisfied_by):
+            req.should_reinstall = True
+        req.satisfied_by = None
+
+    def _check_skip_installed(self, req_to_install):
+        # type: (InstallRequirement) -> Optional[str]
+        """Check if req_to_install should be skipped.
+
+        This will check if the req is installed, and whether we should upgrade
+        or reinstall it, taking into account all the relevant user options.
+
+        After calling this req_to_install will only have satisfied_by set to
+        None if the req_to_install is to be upgraded/reinstalled etc. Any
+        other value will be a dist recording the current thing installed that
+        satisfies the requirement.
+
+        Note that for vcs urls and the like we can't assess skipping in this
+        routine - we simply identify that we need to pull the thing down,
+        then later on it is pulled down and introspected to assess upgrade/
+        reinstalls etc.
+
+        :return: A text reason for why it was skipped, or None.
+        """
+        if self.ignore_installed:
+            return None
+
+        req_to_install.check_if_exists(self.use_user_site)
+        if not req_to_install.satisfied_by:
+            return None
+
+        if self.force_reinstall:
+            self._set_req_to_reinstall(req_to_install)
+            return None
+
+        if not self._is_upgrade_allowed(req_to_install):
+            if self.upgrade_strategy == "only-if-needed":
+                return 'already satisfied, skipping upgrade'
+            return 'already satisfied'
+
+        # Check for the possibility of an upgrade.  For link-based
+        # requirements we have to pull the tree down and inspect to assess
+        # the version #, so it's handled way down.
+        if not req_to_install.link:
+            try:
+                self.finder.find_requirement(req_to_install, upgrade=True)
+            except BestVersionAlreadyInstalled:
+                # Then the best version is installed.
+                return 'already up-to-date'
+            except DistributionNotFound:
+                # No distribution found, so we squash the error.  It will
+                # be raised later when we re-try later to do the install.
+                # Why don't we just raise here?
+                pass
+
+        self._set_req_to_reinstall(req_to_install)
+        return None
+
+    def _get_abstract_dist_for(self, req):
+        # type: (InstallRequirement) -> AbstractDistribution
+        """Takes a InstallRequirement and returns a single AbstractDist \
+        representing a prepared variant of the same.
+        """
+        if req.editable:
+            return self.preparer.prepare_editable_requirement(req)
+
+        # satisfied_by is only evaluated by calling _check_skip_installed,
+        # so it must be None here.
+        assert req.satisfied_by is None
+        skip_reason = self._check_skip_installed(req)
+
+        if req.satisfied_by:
+            return self.preparer.prepare_installed_requirement(
+                req, skip_reason
+            )
+
+        upgrade_allowed = self._is_upgrade_allowed(req)
+
+        # We eagerly populate the link, since that's our "legacy" behavior.
+        require_hashes = self.preparer.require_hashes
+        req.populate_link(self.finder, upgrade_allowed, require_hashes)
+        abstract_dist = self.preparer.prepare_linked_requirement(req)
+
+        # NOTE
+        # The following portion is for determining if a certain package is
+        # going to be re-installed/upgraded or not and reporting to the user.
+        # This should probably get cleaned up in a future refactor.
+
+        # req.req is only avail after unpack for URL
+        # pkgs repeat check_if_exists to uninstall-on-upgrade
+        # (#14)
+        if not self.ignore_installed:
+            req.check_if_exists(self.use_user_site)
+
+        if req.satisfied_by:
+            should_modify = (
+                self.upgrade_strategy != "to-satisfy-only" or
+                self.force_reinstall or
+                self.ignore_installed or
+                req.link.scheme == 'file'
+            )
+            if should_modify:
+                self._set_req_to_reinstall(req)
+            else:
+                logger.info(
+                    'Requirement already satisfied (use --upgrade to upgrade):'
+                    ' %s', req,
+                )
+
+        return abstract_dist
+
+    def _resolve_one(
+        self,
+        requirement_set,  # type: RequirementSet
+        req_to_install,  # type: InstallRequirement
+    ):
+        # type: (...) -> List[InstallRequirement]
+        """Prepare a single requirements file.
+
+        :return: A list of additional InstallRequirements to also install.
+        """
+        # Tell user what we are doing for this requirement:
+        # obtain (editable), skipping, processing (local url), collecting
+        # (remote url or package name)
+        if req_to_install.constraint or req_to_install.prepared:
+            return []
+
+        req_to_install.prepared = True
+
+        # register tmp src for cleanup in case something goes wrong
+        requirement_set.reqs_to_cleanup.append(req_to_install)
+
+        abstract_dist = self._get_abstract_dist_for(req_to_install)
+
+        # Parse and return dependencies
+        dist = abstract_dist.get_pkg_resources_distribution()
+        # This will raise UnsupportedPythonVersion if the given Python
+        # version isn't compatible with the distribution's Requires-Python.
+        _check_dist_requires_python(
+            dist, version_info=self._py_version_info,
+            ignore_requires_python=self.ignore_requires_python,
+        )
+
+        more_reqs = []  # type: List[InstallRequirement]
+
+        def add_req(subreq, extras_requested):
+            sub_install_req = self._make_install_req(
+                str(subreq),
+                req_to_install,
+            )
+            parent_req_name = req_to_install.name
+            to_scan_again, add_to_parent = requirement_set.add_requirement(
+                sub_install_req,
+                parent_req_name=parent_req_name,
+                extras_requested=extras_requested,
+            )
+            if parent_req_name and add_to_parent:
+                self._discovered_dependencies[parent_req_name].append(
+                    add_to_parent
+                )
+            more_reqs.extend(to_scan_again)
+
+        with indent_log():
+            # We add req_to_install before its dependencies, so that we
+            # can refer to it when adding dependencies.
+            if not requirement_set.has_requirement(req_to_install.name):
+                # 'unnamed' requirements will get added here
+                # 'unnamed' requirements can only come from being directly
+                # provided by the user.
+                assert req_to_install.is_direct
+                requirement_set.add_requirement(
+                    req_to_install, parent_req_name=None,
+                )
+
+            if not self.ignore_dependencies:
+                if req_to_install.extras:
+                    logger.debug(
+                        "Installing extra requirements: %r",
+                        ','.join(req_to_install.extras),
+                    )
+                missing_requested = sorted(
+                    set(req_to_install.extras) - set(dist.extras)
+                )
+                for missing in missing_requested:
+                    logger.warning(
+                        '%s does not provide the extra \'%s\'',
+                        dist, missing
+                    )
+
+                available_requested = sorted(
+                    set(dist.extras) & set(req_to_install.extras)
+                )
+                for subreq in dist.requires(available_requested):
+                    add_req(subreq, extras_requested=available_requested)
+
+            if not req_to_install.editable and not req_to_install.satisfied_by:
+                # XXX: --no-install leads this to report 'Successfully
+                # downloaded' for only non-editable reqs, even though we took
+                # action on them.
+                requirement_set.successfully_downloaded.append(req_to_install)
+
+        return more_reqs
+
+    def get_installation_order(self, req_set):
+        # type: (RequirementSet) -> List[InstallRequirement]
+        """Create the installation order.
+
+        The installation order is topological - requirements are installed
+        before the requiring thing. We break cycles at an arbitrary point,
+        and make no other guarantees.
+        """
+        # The current implementation, which we may change at any point
+        # installs the user specified things in the order given, except when
+        # dependencies must come earlier to achieve topological order.
+        order = []
+        ordered_reqs = set()  # type: Set[InstallRequirement]
+
+        def schedule(req):
+            if req.satisfied_by or req in ordered_reqs:
+                return
+            if req.constraint:
+                return
+            ordered_reqs.add(req)
+            for dep in self._discovered_dependencies[req.name]:
+                schedule(dep)
+            order.append(req)
+
+        for install_req in req_set.requirements.values():
+            schedule(install_req)
+        return order

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/locations.py

@@ -0,0 +1,194 @@
+"""Locations where we look for configs, install stuff, etc"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import os
+import os.path
+import platform
+import site
+import sys
+import sysconfig
+from distutils import sysconfig as distutils_sysconfig
+from distutils.command.install import SCHEME_KEYS  # type: ignore
+from distutils.command.install import install as distutils_install_command
+
+from pip._internal.models.scheme import Scheme
+from pip._internal.utils import appdirs
+from pip._internal.utils.compat import WINDOWS
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING, cast
+from pip._internal.utils.virtualenv import running_under_virtualenv
+
+if MYPY_CHECK_RUNNING:
+    from typing import Dict, List, Optional, Union
+
+    from distutils.cmd import Command as DistutilsCommand
+
+
+# Application Directories
+USER_CACHE_DIR = appdirs.user_cache_dir("pip")
+
+
+def get_major_minor_version():
+    # type: () -> str
+    """
+    Return the major-minor version of the current Python as a string, e.g.
+    "3.7" or "3.10".
+    """
+    return '{}.{}'.format(*sys.version_info)
+
+
+def get_src_prefix():
+    # type: () -> str
+    if running_under_virtualenv():
+        src_prefix = os.path.join(sys.prefix, 'src')
+    else:
+        # FIXME: keep src in cwd for now (it is not a temporary folder)
+        try:
+            src_prefix = os.path.join(os.getcwd(), 'src')
+        except OSError:
+            # In case the current working directory has been renamed or deleted
+            sys.exit(
+                "The folder you are executing pip from can no longer be found."
+            )
+
+    # under macOS + virtualenv sys.prefix is not properly resolved
+    # it is something like /path/to/python/bin/..
+    return os.path.abspath(src_prefix)
+
+
+# FIXME doesn't account for venv linked to global site-packages
+
+site_packages = sysconfig.get_path("purelib")  # type: Optional[str]
+
+# This is because of a bug in PyPy's sysconfig module, see
+# https://bitbucket.org/pypy/pypy/issues/2506/sysconfig-returns-incorrect-paths
+# for more information.
+if platform.python_implementation().lower() == "pypy":
+    site_packages = distutils_sysconfig.get_python_lib()
+try:
+    # Use getusersitepackages if this is present, as it ensures that the
+    # value is initialised properly.
+    user_site = site.getusersitepackages()
+except AttributeError:
+    user_site = site.USER_SITE
+
+if WINDOWS:
+    bin_py = os.path.join(sys.prefix, 'Scripts')
+    bin_user = os.path.join(user_site, 'Scripts')
+    # buildout uses 'bin' on Windows too?
+    if not os.path.exists(bin_py):
+        bin_py = os.path.join(sys.prefix, 'bin')
+        bin_user = os.path.join(user_site, 'bin')
+else:
+    bin_py = os.path.join(sys.prefix, 'bin')
+    bin_user = os.path.join(user_site, 'bin')
+
+    # Forcing to use /usr/local/bin for standard macOS framework installs
+    # Also log to ~/Library/Logs/ for use with the Console.app log viewer
+    if sys.platform[:6] == 'darwin' and sys.prefix[:16] == '/System/Library/':
+        bin_py = '/usr/local/bin'
+
+
+def distutils_scheme(
+    dist_name, user=False, home=None, root=None, isolated=False, prefix=None
+):
+    # type:(str, bool, str, str, bool, str) -> Dict[str, str]
+    """
+    Return a distutils install scheme
+    """
+    from distutils.dist import Distribution
+
+    dist_args = {'name': dist_name}  # type: Dict[str, Union[str, List[str]]]
+    if isolated:
+        dist_args["script_args"] = ["--no-user-cfg"]
+
+    d = Distribution(dist_args)
+    d.parse_config_files()
+    obj = None  # type: Optional[DistutilsCommand]
+    obj = d.get_command_obj('install', create=True)
+    assert obj is not None
+    i = cast(distutils_install_command, obj)
+    # NOTE: setting user or home has the side-effect of creating the home dir
+    # or user base for installations during finalize_options()
+    # ideally, we'd prefer a scheme class that has no side-effects.
+    assert not (user and prefix), "user={} prefix={}".format(user, prefix)
+    assert not (home and prefix), "home={} prefix={}".format(home, prefix)
+    i.user = user or i.user
+    if user or home:
+        i.prefix = ""
+    i.prefix = prefix or i.prefix
+    i.home = home or i.home
+    i.root = root or i.root
+    i.finalize_options()
+
+    scheme = {}
+    for key in SCHEME_KEYS:
+        scheme[key] = getattr(i, 'install_' + key)
+
+    # install_lib specified in setup.cfg should install *everything*
+    # into there (i.e. it takes precedence over both purelib and
+    # platlib).  Note, i.install_lib is *always* set after
+    # finalize_options(); we only want to override here if the user
+    # has explicitly requested it hence going back to the config
+    if 'install_lib' in d.get_option_dict('install'):
+        scheme.update(dict(purelib=i.install_lib, platlib=i.install_lib))
+
+    if running_under_virtualenv():
+        scheme['headers'] = os.path.join(
+            sys.prefix,
+            'include',
+            'site',
+            'python{}'.format(get_major_minor_version()),
+            dist_name,
+        )
+
+        if root is not None:
+            path_no_drive = os.path.splitdrive(
+                os.path.abspath(scheme["headers"]))[1]
+            scheme["headers"] = os.path.join(
+                root,
+                path_no_drive[1:],
+            )
+
+    return scheme
+
+
+def get_scheme(
+    dist_name,  # type: str
+    user=False,  # type: bool
+    home=None,  # type: Optional[str]
+    root=None,  # type: Optional[str]
+    isolated=False,  # type: bool
+    prefix=None,  # type: Optional[str]
+):
+    # type: (...) -> Scheme
+    """
+    Get the "scheme" corresponding to the input parameters. The distutils
+    documentation provides the context for the available schemes:
+    https://docs.python.org/3/install/index.html#alternate-installation
+
+    :param dist_name: the name of the package to retrieve the scheme for, used
+        in the headers scheme path
+    :param user: indicates to use the "user" scheme
+    :param home: indicates to use the "home" scheme and provides the base
+        directory for the same
+    :param root: root under which other directories are re-based
+    :param isolated: equivalent to --no-user-cfg, i.e. do not consider
+        ~/.pydistutils.cfg (posix) or ~/pydistutils.cfg (non-posix) for
+        scheme paths
+    :param prefix: indicates to use the "prefix" scheme and provides the
+        base directory for the same
+    """
+    scheme = distutils_scheme(
+        dist_name, user, home, root, isolated, prefix
+    )
+    return Scheme(
+        platlib=scheme["platlib"],
+        purelib=scheme["purelib"],
+        headers=scheme["headers"],
+        scripts=scheme["scripts"],
+        data=scheme["data"],
+    )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/main.py

@@ -0,0 +1,16 @@
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, List
+
+
+def main(args=None):
+    # type: (Optional[List[str]]) -> int
+    """This is preserved for old console scripts that may still be referencing
+    it.
+
+    For additional details, see https://github.com/pypa/pip/issues/7498.
+    """
+    from pip._internal.utils.entrypoints import _wrapper
+
+    return _wrapper(args)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/__init__.py

@@ -0,0 +1,2 @@
+"""A package that contains models that represent entities.
+"""

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/candidate.py

@@ -0,0 +1,36 @@
+from pip._vendor.packaging.version import parse as parse_version
+
+from pip._internal.utils.models import KeyBasedCompareMixin
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from pip._vendor.packaging.version import _BaseVersion
+    from pip._internal.models.link import Link
+
+
+class InstallationCandidate(KeyBasedCompareMixin):
+    """Represents a potential "candidate" for installation.
+    """
+
+    def __init__(self, name, version, link):
+        # type: (str, str, Link) -> None
+        self.name = name
+        self.version = parse_version(version)  # type: _BaseVersion
+        self.link = link
+
+        super(InstallationCandidate, self).__init__(
+            key=(self.name, self.version, self.link),
+            defining_class=InstallationCandidate
+        )
+
+    def __repr__(self):
+        # type: () -> str
+        return "<InstallationCandidate({!r}, {!r}, {!r})>".format(
+            self.name, self.version, self.link,
+        )
+
+    def __str__(self):
+        # type: () -> str
+        return '{!r} candidate (version {} at {})'.format(
+            self.name, self.version, self.link,
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/format_control.py

@@ -0,0 +1,84 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal.exceptions import CommandError
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Set, FrozenSet
+
+
+class FormatControl(object):
+    """Helper for managing formats from which a package can be installed.
+    """
+
+    def __init__(self, no_binary=None, only_binary=None):
+        # type: (Optional[Set[str]], Optional[Set[str]]) -> None
+        if no_binary is None:
+            no_binary = set()
+        if only_binary is None:
+            only_binary = set()
+
+        self.no_binary = no_binary
+        self.only_binary = only_binary
+
+    def __eq__(self, other):
+        # type: (object) -> bool
+        return self.__dict__ == other.__dict__
+
+    def __ne__(self, other):
+        # type: (object) -> bool
+        return not self.__eq__(other)
+
+    def __repr__(self):
+        # type: () -> str
+        return "{}({}, {})".format(
+            self.__class__.__name__,
+            self.no_binary,
+            self.only_binary
+        )
+
+    @staticmethod
+    def handle_mutual_excludes(value, target, other):
+        # type: (str, Optional[Set[str]], Optional[Set[str]]) -> None
+        if value.startswith('-'):
+            raise CommandError(
+                "--no-binary / --only-binary option requires 1 argument."
+            )
+        new = value.split(',')
+        while ':all:' in new:
+            other.clear()
+            target.clear()
+            target.add(':all:')
+            del new[:new.index(':all:') + 1]
+            # Without a none, we want to discard everything as :all: covers it
+            if ':none:' not in new:
+                return
+        for name in new:
+            if name == ':none:':
+                target.clear()
+                continue
+            name = canonicalize_name(name)
+            other.discard(name)
+            target.add(name)
+
+    def get_allowed_formats(self, canonical_name):
+        # type: (str) -> FrozenSet[str]
+        result = {"binary", "source"}
+        if canonical_name in self.only_binary:
+            result.discard('source')
+        elif canonical_name in self.no_binary:
+            result.discard('binary')
+        elif ':all:' in self.only_binary:
+            result.discard('source')
+        elif ':all:' in self.no_binary:
+            result.discard('binary')
+        return frozenset(result)
+
+    def disallow_binaries(self):
+        # type: () -> None
+        self.handle_mutual_excludes(
+            ':all:', self.no_binary, self.only_binary,
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/index.py

@@ -0,0 +1,31 @@
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+
+class PackageIndex(object):
+    """Represents a Package Index and provides easier access to endpoints
+    """
+
+    def __init__(self, url, file_storage_domain):
+        # type: (str, str) -> None
+        super(PackageIndex, self).__init__()
+        self.url = url
+        self.netloc = urllib_parse.urlsplit(url).netloc
+        self.simple_url = self._url_for_path('simple')
+        self.pypi_url = self._url_for_path('pypi')
+
+        # This is part of a temporary hack used to block installs of PyPI
+        # packages which depend on external urls only necessary until PyPI can
+        # block such packages themselves
+        self.file_storage_domain = file_storage_domain
+
+    def _url_for_path(self, path):
+        # type: (str) -> str
+        return urllib_parse.urljoin(self.url, path)
+
+
+PyPI = PackageIndex(
+    'https://pypi.org/', file_storage_domain='files.pythonhosted.org'
+)
+TestPyPI = PackageIndex(
+    'https://test.pypi.org/', file_storage_domain='test-files.pythonhosted.org'
+)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/link.py

@@ -0,0 +1,227 @@
+import os
+import posixpath
+import re
+
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.utils.filetypes import WHEEL_EXTENSION
+from pip._internal.utils.misc import (
+    redact_auth_from_url,
+    split_auth_from_netloc,
+    splitext,
+)
+from pip._internal.utils.models import KeyBasedCompareMixin
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url, url_to_path
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Text, Tuple, Union
+    from pip._internal.index.collector import HTMLPage
+    from pip._internal.utils.hashes import Hashes
+
+
+class Link(KeyBasedCompareMixin):
+    """Represents a parsed link from a Package Index's simple URL
+    """
+
+    def __init__(
+        self,
+        url,                   # type: str
+        comes_from=None,       # type: Optional[Union[str, HTMLPage]]
+        requires_python=None,  # type: Optional[str]
+        yanked_reason=None,    # type: Optional[Text]
+    ):
+        # type: (...) -> None
+        """
+        :param url: url of the resource pointed to (href of the link)
+        :param comes_from: instance of HTMLPage where the link was found,
+            or string.
+        :param requires_python: String containing the `Requires-Python`
+            metadata field, specified in PEP 345. This may be specified by
+            a data-requires-python attribute in the HTML link tag, as
+            described in PEP 503.
+        :param yanked_reason: the reason the file has been yanked, if the
+            file has been yanked, or None if the file hasn't been yanked.
+            This is the value of the "data-yanked" attribute, if present, in
+            a simple repository HTML link. If the file has been yanked but
+            no reason was provided, this should be the empty string. See
+            PEP 592 for more information and the specification.
+        """
+
+        # url can be a UNC windows share
+        if url.startswith('\\\\'):
+            url = path_to_url(url)
+
+        self._parsed_url = urllib_parse.urlsplit(url)
+        # Store the url as a private attribute to prevent accidentally
+        # trying to set a new value.
+        self._url = url
+
+        self.comes_from = comes_from
+        self.requires_python = requires_python if requires_python else None
+        self.yanked_reason = yanked_reason
+
+        super(Link, self).__init__(key=url, defining_class=Link)
+
+    def __str__(self):
+        # type: () -> str
+        if self.requires_python:
+            rp = ' (requires-python:%s)' % self.requires_python
+        else:
+            rp = ''
+        if self.comes_from:
+            return '%s (from %s)%s' % (redact_auth_from_url(self._url),
+                                       self.comes_from, rp)
+        else:
+            return redact_auth_from_url(str(self._url))
+
+    def __repr__(self):
+        # type: () -> str
+        return '<Link %s>' % self
+
+    @property
+    def url(self):
+        # type: () -> str
+        return self._url
+
+    @property
+    def filename(self):
+        # type: () -> str
+        path = self.path.rstrip('/')
+        name = posixpath.basename(path)
+        if not name:
+            # Make sure we don't leak auth information if the netloc
+            # includes a username and password.
+            netloc, user_pass = split_auth_from_netloc(self.netloc)
+            return netloc
+
+        name = urllib_parse.unquote(name)
+        assert name, ('URL %r produced no filename' % self._url)
+        return name
+
+    @property
+    def file_path(self):
+        # type: () -> str
+        return url_to_path(self.url)
+
+    @property
+    def scheme(self):
+        # type: () -> str
+        return self._parsed_url.scheme
+
+    @property
+    def netloc(self):
+        # type: () -> str
+        """
+        This can contain auth information.
+        """
+        return self._parsed_url.netloc
+
+    @property
+    def path(self):
+        # type: () -> str
+        return urllib_parse.unquote(self._parsed_url.path)
+
+    def splitext(self):
+        # type: () -> Tuple[str, str]
+        return splitext(posixpath.basename(self.path.rstrip('/')))
+
+    @property
+    def ext(self):
+        # type: () -> str
+        return self.splitext()[1]
+
+    @property
+    def url_without_fragment(self):
+        # type: () -> str
+        scheme, netloc, path, query, fragment = self._parsed_url
+        return urllib_parse.urlunsplit((scheme, netloc, path, query, None))
+
+    _egg_fragment_re = re.compile(r'[#&]egg=([^&]*)')
+
+    @property
+    def egg_fragment(self):
+        # type: () -> Optional[str]
+        match = self._egg_fragment_re.search(self._url)
+        if not match:
+            return None
+        return match.group(1)
+
+    _subdirectory_fragment_re = re.compile(r'[#&]subdirectory=([^&]*)')
+
+    @property
+    def subdirectory_fragment(self):
+        # type: () -> Optional[str]
+        match = self._subdirectory_fragment_re.search(self._url)
+        if not match:
+            return None
+        return match.group(1)
+
+    _hash_re = re.compile(
+        r'(sha1|sha224|sha384|sha256|sha512|md5)=([a-f0-9]+)'
+    )
+
+    @property
+    def hash(self):
+        # type: () -> Optional[str]
+        match = self._hash_re.search(self._url)
+        if match:
+            return match.group(2)
+        return None
+
+    @property
+    def hash_name(self):
+        # type: () -> Optional[str]
+        match = self._hash_re.search(self._url)
+        if match:
+            return match.group(1)
+        return None
+
+    @property
+    def show_url(self):
+        # type: () -> str
+        return posixpath.basename(self._url.split('#', 1)[0].split('?', 1)[0])
+
+    @property
+    def is_file(self):
+        # type: () -> bool
+        return self.scheme == 'file'
+
+    def is_existing_dir(self):
+        # type: () -> bool
+        return self.is_file and os.path.isdir(self.file_path)
+
+    @property
+    def is_wheel(self):
+        # type: () -> bool
+        return self.ext == WHEEL_EXTENSION
+
+    @property
+    def is_vcs(self):
+        # type: () -> bool
+        from pip._internal.vcs import vcs
+
+        return self.scheme in vcs.all_schemes
+
+    @property
+    def is_yanked(self):
+        # type: () -> bool
+        return self.yanked_reason is not None
+
+    @property
+    def has_hash(self):
+        # type: () -> bool
+        return self.hash_name is not None
+
+    def is_hash_allowed(self, hashes):
+        # type: (Optional[Hashes]) -> bool
+        """
+        Return True if the link has a hash and it is allowed.
+        """
+        if hashes is None or not self.has_hash:
+            return False
+        # Assert non-None so mypy knows self.hash_name and self.hash are str.
+        assert self.hash_name is not None
+        assert self.hash is not None
+
+        return hashes.is_hash_allowed(self.hash_name, hex_digest=self.hash)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/scheme.py

@@ -0,0 +1,25 @@
+"""
+For types associated with installation schemes.
+
+For a general overview of available schemes and their context, see
+https://docs.python.org/3/install/index.html#alternate-installation.
+"""
+
+
+class Scheme(object):
+    """A Scheme holds paths which are used as the base directories for
+    artifacts associated with a Python package.
+    """
+    def __init__(
+        self,
+        platlib,  # type: str
+        purelib,  # type: str
+        headers,  # type: str
+        scripts,  # type: str
+        data,  # type: str
+    ):
+        self.platlib = platlib
+        self.purelib = purelib
+        self.headers = headers
+        self.scripts = scripts
+        self.data = data

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/search_scope.py

@@ -0,0 +1,114 @@
+import itertools
+import logging
+import os
+import posixpath
+
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.models.index import PyPI
+from pip._internal.utils.compat import has_tls
+from pip._internal.utils.misc import normalize_path, redact_auth_from_url
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List
+
+
+logger = logging.getLogger(__name__)
+
+
+class SearchScope(object):
+
+    """
+    Encapsulates the locations that pip is configured to search.
+    """
+
+    @classmethod
+    def create(
+        cls,
+        find_links,  # type: List[str]
+        index_urls,  # type: List[str]
+    ):
+        # type: (...) -> SearchScope
+        """
+        Create a SearchScope object after normalizing the `find_links`.
+        """
+        # Build find_links. If an argument starts with ~, it may be
+        # a local file relative to a home directory. So try normalizing
+        # it and if it exists, use the normalized version.
+        # This is deliberately conservative - it might be fine just to
+        # blindly normalize anything starting with a ~...
+        built_find_links = []  # type: List[str]
+        for link in find_links:
+            if link.startswith('~'):
+                new_link = normalize_path(link)
+                if os.path.exists(new_link):
+                    link = new_link
+            built_find_links.append(link)
+
+        # If we don't have TLS enabled, then WARN if anyplace we're looking
+        # relies on TLS.
+        if not has_tls():
+            for link in itertools.chain(index_urls, built_find_links):
+                parsed = urllib_parse.urlparse(link)
+                if parsed.scheme == 'https':
+                    logger.warning(
+                        'pip is configured with locations that require '
+                        'TLS/SSL, however the ssl module in Python is not '
+                        'available.'
+                    )
+                    break
+
+        return cls(
+            find_links=built_find_links,
+            index_urls=index_urls,
+        )
+
+    def __init__(
+        self,
+        find_links,  # type: List[str]
+        index_urls,  # type: List[str]
+    ):
+        # type: (...) -> None
+        self.find_links = find_links
+        self.index_urls = index_urls
+
+    def get_formatted_locations(self):
+        # type: () -> str
+        lines = []
+        if self.index_urls and self.index_urls != [PyPI.simple_url]:
+            lines.append(
+                'Looking in indexes: {}'.format(', '.join(
+                    redact_auth_from_url(url) for url in self.index_urls))
+            )
+        if self.find_links:
+            lines.append(
+                'Looking in links: {}'.format(', '.join(
+                    redact_auth_from_url(url) for url in self.find_links))
+            )
+        return '\n'.join(lines)
+
+    def get_index_urls_locations(self, project_name):
+        # type: (str) -> List[str]
+        """Returns the locations found via self.index_urls
+
+        Checks the url_name on the main (first in the list) index and
+        use this url_name to produce all locations
+        """
+
+        def mkurl_pypi_url(url):
+            # type: (str) -> str
+            loc = posixpath.join(
+                url,
+                urllib_parse.quote(canonicalize_name(project_name)))
+            # For maximum compatibility with easy_install, ensure the path
+            # ends in a trailing slash.  Although this isn't in the spec
+            # (and PyPI can handle it without the slash) some other index
+            # implementations might break if they relied on easy_install's
+            # behavior.
+            if not loc.endswith('/'):
+                loc = loc + '/'
+            return loc
+
+        return [mkurl_pypi_url(url) for url in self.index_urls]

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/selection_prefs.py

@@ -0,0 +1,47 @@
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+    from pip._internal.models.format_control import FormatControl
+
+
+class SelectionPreferences(object):
+
+    """
+    Encapsulates the candidate selection preferences for downloading
+    and installing files.
+    """
+
+    # Don't include an allow_yanked default value to make sure each call
+    # site considers whether yanked releases are allowed. This also causes
+    # that decision to be made explicit in the calling code, which helps
+    # people when reading the code.
+    def __init__(
+        self,
+        allow_yanked,  # type: bool
+        allow_all_prereleases=False,  # type: bool
+        format_control=None,          # type: Optional[FormatControl]
+        prefer_binary=False,          # type: bool
+        ignore_requires_python=None,  # type: Optional[bool]
+    ):
+        # type: (...) -> None
+        """Create a SelectionPreferences object.
+
+        :param allow_yanked: Whether files marked as yanked (in the sense
+            of PEP 592) are permitted to be candidates for install.
+        :param format_control: A FormatControl object or None. Used to control
+            the selection of source packages / binary packages when consulting
+            the index and links.
+        :param prefer_binary: Whether to prefer an old, but valid, binary
+            dist over a new source dist.
+        :param ignore_requires_python: Whether to ignore incompatible
+            "Requires-Python" values in links. Defaults to False.
+        """
+        if ignore_requires_python is None:
+            ignore_requires_python = False
+
+        self.allow_yanked = allow_yanked
+        self.allow_all_prereleases = allow_all_prereleases
+        self.format_control = format_control
+        self.prefer_binary = prefer_binary
+        self.ignore_requires_python = ignore_requires_python

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/target_python.py

@@ -0,0 +1,107 @@
+import sys
+
+from pip._internal.pep425tags import get_supported, version_info_to_nodot
+from pip._internal.utils.misc import normalize_version_info
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional, Tuple
+
+    from pip._vendor.packaging.tags import Tag
+
+
+class TargetPython(object):
+
+    """
+    Encapsulates the properties of a Python interpreter one is targeting
+    for a package install, download, etc.
+    """
+
+    def __init__(
+        self,
+        platform=None,  # type: Optional[str]
+        py_version_info=None,  # type: Optional[Tuple[int, ...]]
+        abi=None,  # type: Optional[str]
+        implementation=None,  # type: Optional[str]
+    ):
+        # type: (...) -> None
+        """
+        :param platform: A string or None. If None, searches for packages
+            that are supported by the current system. Otherwise, will find
+            packages that can be built on the platform passed in. These
+            packages will only be downloaded for distribution: they will
+            not be built locally.
+        :param py_version_info: An optional tuple of ints representing the
+            Python version information to use (e.g. `sys.version_info[:3]`).
+            This can have length 1, 2, or 3 when provided.
+        :param abi: A string or None. This is passed to pep425tags.py's
+            get_supported() function as is.
+        :param implementation: A string or None. This is passed to
+            pep425tags.py's get_supported() function as is.
+        """
+        # Store the given py_version_info for when we call get_supported().
+        self._given_py_version_info = py_version_info
+
+        if py_version_info is None:
+            py_version_info = sys.version_info[:3]
+        else:
+            py_version_info = normalize_version_info(py_version_info)
+
+        py_version = '.'.join(map(str, py_version_info[:2]))
+
+        self.abi = abi
+        self.implementation = implementation
+        self.platform = platform
+        self.py_version = py_version
+        self.py_version_info = py_version_info
+
+        # This is used to cache the return value of get_tags().
+        self._valid_tags = None  # type: Optional[List[Tag]]
+
+    def format_given(self):
+        # type: () -> str
+        """
+        Format the given, non-None attributes for display.
+        """
+        display_version = None
+        if self._given_py_version_info is not None:
+            display_version = '.'.join(
+                str(part) for part in self._given_py_version_info
+            )
+
+        key_values = [
+            ('platform', self.platform),
+            ('version_info', display_version),
+            ('abi', self.abi),
+            ('implementation', self.implementation),
+        ]
+        return ' '.join(
+            '{}={!r}'.format(key, value) for key, value in key_values
+            if value is not None
+        )
+
+    def get_tags(self):
+        # type: () -> List[Tag]
+        """
+        Return the supported PEP 425 tags to check wheel candidates against.
+
+        The tags are returned in order of preference (most preferred first).
+        """
+        if self._valid_tags is None:
+            # Pass versions=None if no py_version_info was given since
+            # versions=None uses special default logic.
+            py_version_info = self._given_py_version_info
+            if py_version_info is None:
+                version = None
+            else:
+                version = version_info_to_nodot(py_version_info)
+
+            tags = get_supported(
+                version=version,
+                platform=self.platform,
+                abi=self.abi,
+                impl=self.implementation,
+            )
+            self._valid_tags = tags
+
+        return self._valid_tags

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/models/wheel.py

@@ -0,0 +1,78 @@
+"""Represents a wheel file and provides access to the various parts of the
+name that have meaning.
+"""
+import re
+
+from pip._vendor.packaging.tags import Tag
+
+from pip._internal.exceptions import InvalidWheelFilename
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List
+
+
+class Wheel(object):
+    """A wheel file"""
+
+    wheel_file_re = re.compile(
+        r"""^(?P<namever>(?P<name>[^\s-]+?)-(?P<ver>[^\s-]*?))
+        ((-(?P<build>\d[^-]*?))?-(?P<pyver>[^\s-]+?)-(?P<abi>[^\s-]+?)-(?P<plat>[^\s-]+?)
+        \.whl|\.dist-info)$""",
+        re.VERBOSE
+    )
+
+    def __init__(self, filename):
+        # type: (str) -> None
+        """
+        :raises InvalidWheelFilename: when the filename is invalid for a wheel
+        """
+        wheel_info = self.wheel_file_re.match(filename)
+        if not wheel_info:
+            raise InvalidWheelFilename(
+                "%s is not a valid wheel filename." % filename
+            )
+        self.filename = filename
+        self.name = wheel_info.group('name').replace('_', '-')
+        # we'll assume "_" means "-" due to wheel naming scheme
+        # (https://github.com/pypa/pip/issues/1150)
+        self.version = wheel_info.group('ver').replace('_', '-')
+        self.build_tag = wheel_info.group('build')
+        self.pyversions = wheel_info.group('pyver').split('.')
+        self.abis = wheel_info.group('abi').split('.')
+        self.plats = wheel_info.group('plat').split('.')
+
+        # All the tag combinations from this file
+        self.file_tags = {
+            Tag(x, y, z) for x in self.pyversions
+            for y in self.abis for z in self.plats
+        }
+
+    def get_formatted_file_tags(self):
+        # type: () -> List[str]
+        """Return the wheel's tags as a sorted list of strings."""
+        return sorted(str(tag) for tag in self.file_tags)
+
+    def support_index_min(self, tags):
+        # type: (List[Tag]) -> int
+        """Return the lowest index that one of the wheel's file_tag combinations
+        achieves in the given list of supported tags.
+
+        For example, if there are 8 supported tags and one of the file tags
+        is first in the list, then return 0.
+
+        :param tags: the PEP 425 tags to check the wheel against, in order
+            with most preferred first.
+
+        :raises ValueError: If none of the wheel's file tags match one of
+            the supported tags.
+        """
+        return min(tags.index(tag) for tag in self.file_tags if tag in tags)
+
+    def supported(self, tags):
+        # type: (List[Tag]) -> bool
+        """Return whether the wheel is compatible with one of the given tags.
+
+        :param tags: the PEP 425 tags to check the wheel against.
+        """
+        return not self.file_tags.isdisjoint(tags)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/__init__.py

@@ -0,0 +1,2 @@
+"""Contains purely network-related utilities.
+"""

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/auth.py

@@ -0,0 +1,298 @@
+"""Network Authentication Helpers
+
+Contains interface (MultiDomainBasicAuth) and associated glue code for
+providing credentials in the context of network requests.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+
+from pip._vendor.requests.auth import AuthBase, HTTPBasicAuth
+from pip._vendor.requests.utils import get_netrc_auth
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.utils.misc import (
+    ask,
+    ask_input,
+    ask_password,
+    remove_auth_from_url,
+    split_auth_netloc_from_url,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import Dict, Optional, Tuple
+
+    from pip._internal.vcs.versioncontrol import AuthInfo
+
+    Credentials = Tuple[str, str, str]
+
+logger = logging.getLogger(__name__)
+
+try:
+    import keyring  # noqa
+except ImportError:
+    keyring = None
+except Exception as exc:
+    logger.warning(
+        "Keyring is skipped due to an exception: %s", str(exc),
+    )
+    keyring = None
+
+
+def get_keyring_auth(url, username):
+    """Return the tuple auth for a given url from keyring."""
+    if not url or not keyring:
+        return None
+
+    try:
+        try:
+            get_credential = keyring.get_credential
+        except AttributeError:
+            pass
+        else:
+            logger.debug("Getting credentials from keyring for %s", url)
+            cred = get_credential(url, username)
+            if cred is not None:
+                return cred.username, cred.password
+            return None
+
+        if username:
+            logger.debug("Getting password from keyring for %s", url)
+            password = keyring.get_password(url, username)
+            if password:
+                return username, password
+
+    except Exception as exc:
+        logger.warning(
+            "Keyring is skipped due to an exception: %s", str(exc),
+        )
+
+
+class MultiDomainBasicAuth(AuthBase):
+
+    def __init__(self, prompting=True, index_urls=None):
+        # type: (bool, Optional[Values]) -> None
+        self.prompting = prompting
+        self.index_urls = index_urls
+        self.passwords = {}  # type: Dict[str, AuthInfo]
+        # When the user is prompted to enter credentials and keyring is
+        # available, we will offer to save them. If the user accepts,
+        # this value is set to the credentials they entered. After the
+        # request authenticates, the caller should call
+        # ``save_credentials`` to save these.
+        self._credentials_to_save = None  # type: Optional[Credentials]
+
+    def _get_index_url(self, url):
+        """Return the original index URL matching the requested URL.
+
+        Cached or dynamically generated credentials may work against
+        the original index URL rather than just the netloc.
+
+        The provided url should have had its username and password
+        removed already. If the original index url had credentials then
+        they will be included in the return value.
+
+        Returns None if no matching index was found, or if --no-index
+        was specified by the user.
+        """
+        if not url or not self.index_urls:
+            return None
+
+        for u in self.index_urls:
+            prefix = remove_auth_from_url(u).rstrip("/") + "/"
+            if url.startswith(prefix):
+                return u
+
+    def _get_new_credentials(self, original_url, allow_netrc=True,
+                             allow_keyring=True):
+        """Find and return credentials for the specified URL."""
+        # Split the credentials and netloc from the url.
+        url, netloc, url_user_password = split_auth_netloc_from_url(
+            original_url,
+        )
+
+        # Start with the credentials embedded in the url
+        username, password = url_user_password
+        if username is not None and password is not None:
+            logger.debug("Found credentials in url for %s", netloc)
+            return url_user_password
+
+        # Find a matching index url for this request
+        index_url = self._get_index_url(url)
+        if index_url:
+            # Split the credentials from the url.
+            index_info = split_auth_netloc_from_url(index_url)
+            if index_info:
+                index_url, _, index_url_user_password = index_info
+                logger.debug("Found index url %s", index_url)
+
+        # If an index URL was found, try its embedded credentials
+        if index_url and index_url_user_password[0] is not None:
+            username, password = index_url_user_password
+            if username is not None and password is not None:
+                logger.debug("Found credentials in index url for %s", netloc)
+                return index_url_user_password
+
+        # Get creds from netrc if we still don't have them
+        if allow_netrc:
+            netrc_auth = get_netrc_auth(original_url)
+            if netrc_auth:
+                logger.debug("Found credentials in netrc for %s", netloc)
+                return netrc_auth
+
+        # If we don't have a password and keyring is available, use it.
+        if allow_keyring:
+            # The index url is more specific than the netloc, so try it first
+            kr_auth = (
+                get_keyring_auth(index_url, username) or
+                get_keyring_auth(netloc, username)
+            )
+            if kr_auth:
+                logger.debug("Found credentials in keyring for %s", netloc)
+                return kr_auth
+
+        return username, password
+
+    def _get_url_and_credentials(self, original_url):
+        """Return the credentials to use for the provided URL.
+
+        If allowed, netrc and keyring may be used to obtain the
+        correct credentials.
+
+        Returns (url_without_credentials, username, password). Note
+        that even if the original URL contains credentials, this
+        function may return a different username and password.
+        """
+        url, netloc, _ = split_auth_netloc_from_url(original_url)
+
+        # Use any stored credentials that we have for this netloc
+        username, password = self.passwords.get(netloc, (None, None))
+
+        if username is None and password is None:
+            # No stored credentials. Acquire new credentials without prompting
+            # the user. (e.g. from netrc, keyring, or the URL itself)
+            username, password = self._get_new_credentials(original_url)
+
+        if username is not None or password is not None:
+            # Convert the username and password if they're None, so that
+            # this netloc will show up as "cached" in the conditional above.
+            # Further, HTTPBasicAuth doesn't accept None, so it makes sense to
+            # cache the value that is going to be used.
+            username = username or ""
+            password = password or ""
+
+            # Store any acquired credentials.
+            self.passwords[netloc] = (username, password)
+
+        assert (
+            # Credentials were found
+            (username is not None and password is not None) or
+            # Credentials were not found
+            (username is None and password is None)
+        ), "Could not load credentials from url: {}".format(original_url)
+
+        return url, username, password
+
+    def __call__(self, req):
+        # Get credentials for this request
+        url, username, password = self._get_url_and_credentials(req.url)
+
+        # Set the url of the request to the url without any credentials
+        req.url = url
+
+        if username is not None and password is not None:
+            # Send the basic auth with this request
+            req = HTTPBasicAuth(username, password)(req)
+
+        # Attach a hook to handle 401 responses
+        req.register_hook("response", self.handle_401)
+
+        return req
+
+    # Factored out to allow for easy patching in tests
+    def _prompt_for_password(self, netloc):
+        username = ask_input("User for %s: " % netloc)
+        if not username:
+            return None, None
+        auth = get_keyring_auth(netloc, username)
+        if auth:
+            return auth[0], auth[1], False
+        password = ask_password("Password: ")
+        return username, password, True
+
+    # Factored out to allow for easy patching in tests
+    def _should_save_password_to_keyring(self):
+        if not keyring:
+            return False
+        return ask("Save credentials to keyring [y/N]: ", ["y", "n"]) == "y"
+
+    def handle_401(self, resp, **kwargs):
+        # We only care about 401 responses, anything else we want to just
+        #   pass through the actual response
+        if resp.status_code != 401:
+            return resp
+
+        # We are not able to prompt the user so simply return the response
+        if not self.prompting:
+            return resp
+
+        parsed = urllib_parse.urlparse(resp.url)
+
+        # Prompt the user for a new username and password
+        username, password, save = self._prompt_for_password(parsed.netloc)
+
+        # Store the new username and password to use for future requests
+        self._credentials_to_save = None
+        if username is not None and password is not None:
+            self.passwords[parsed.netloc] = (username, password)
+
+            # Prompt to save the password to keyring
+            if save and self._should_save_password_to_keyring():
+                self._credentials_to_save = (parsed.netloc, username, password)
+
+        # Consume content and release the original connection to allow our new
+        #   request to reuse the same one.
+        resp.content
+        resp.raw.release_conn()
+
+        # Add our new username and password to the request
+        req = HTTPBasicAuth(username or "", password or "")(resp.request)
+        req.register_hook("response", self.warn_on_401)
+
+        # On successful request, save the credentials that were used to
+        # keyring. (Note that if the user responded "no" above, this member
+        # is not set and nothing will be saved.)
+        if self._credentials_to_save:
+            req.register_hook("response", self.save_credentials)
+
+        # Send our new request
+        new_resp = resp.connection.send(req, **kwargs)
+        new_resp.history.append(resp)
+
+        return new_resp
+
+    def warn_on_401(self, resp, **kwargs):
+        """Response callback to warn about incorrect credentials."""
+        if resp.status_code == 401:
+            logger.warning(
+                '401 Error, Credentials not correct for %s', resp.request.url,
+            )
+
+    def save_credentials(self, resp, **kwargs):
+        """Response callback to save credentials on success."""
+        assert keyring is not None, "should never reach here without keyring"
+        if not keyring:
+            return
+
+        creds = self._credentials_to_save
+        self._credentials_to_save = None
+        if creds and resp.status_code < 400:
+            try:
+                logger.info('Saving credentials to keyring')
+                keyring.set_password(*creds)
+            except Exception:
+                logger.exception('Failed to save credentials')

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/cache.py

@@ -0,0 +1,81 @@
+"""HTTP cache implementation.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import os
+from contextlib import contextmanager
+
+from pip._vendor.cachecontrol.cache import BaseCache
+from pip._vendor.cachecontrol.caches import FileCache
+from pip._vendor.requests.models import Response
+
+from pip._internal.utils.filesystem import adjacent_tmp_file, replace
+from pip._internal.utils.misc import ensure_dir
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional
+
+
+def is_from_cache(response):
+    # type: (Response) -> bool
+    return getattr(response, "from_cache", False)
+
+
+@contextmanager
+def suppressed_cache_errors():
+    """If we can't access the cache then we can just skip caching and process
+    requests as if caching wasn't enabled.
+    """
+    try:
+        yield
+    except (OSError, IOError):
+        pass
+
+
+class SafeFileCache(BaseCache):
+    """
+    A file based cache which is safe to use even when the target directory may
+    not be accessible or writable.
+    """
+
+    def __init__(self, directory):
+        # type: (str) -> None
+        assert directory is not None, "Cache directory must not be None."
+        super(SafeFileCache, self).__init__()
+        self.directory = directory
+
+    def _get_cache_path(self, name):
+        # type: (str) -> str
+        # From cachecontrol.caches.file_cache.FileCache._fn, brought into our
+        # class for backwards-compatibility and to avoid using a non-public
+        # method.
+        hashed = FileCache.encode(name)
+        parts = list(hashed[:5]) + [hashed]
+        return os.path.join(self.directory, *parts)
+
+    def get(self, key):
+        # type: (str) -> Optional[bytes]
+        path = self._get_cache_path(key)
+        with suppressed_cache_errors():
+            with open(path, 'rb') as f:
+                return f.read()
+
+    def set(self, key, value):
+        # type: (str, bytes) -> None
+        path = self._get_cache_path(key)
+        with suppressed_cache_errors():
+            ensure_dir(os.path.dirname(path))
+
+            with adjacent_tmp_file(path) as f:
+                f.write(value)
+
+            replace(f.name, path)
+
+    def delete(self, key):
+        # type: (str) -> None
+        path = self._get_cache_path(key)
+        with suppressed_cache_errors():
+            os.remove(path)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/download.py

@@ -0,0 +1,200 @@
+"""Download files with progress indicators.
+"""
+import cgi
+import logging
+import mimetypes
+import os
+
+from pip._vendor import requests
+from pip._vendor.requests.models import CONTENT_CHUNK_SIZE
+
+from pip._internal.models.index import PyPI
+from pip._internal.network.cache import is_from_cache
+from pip._internal.network.utils import response_chunks
+from pip._internal.utils.misc import (
+    format_size,
+    redact_auth_from_url,
+    splitext,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import DownloadProgressProvider
+
+if MYPY_CHECK_RUNNING:
+    from typing import Iterable, Optional
+
+    from pip._vendor.requests.models import Response
+
+    from pip._internal.models.link import Link
+    from pip._internal.network.session import PipSession
+
+logger = logging.getLogger(__name__)
+
+
+def _get_http_response_size(resp):
+    # type: (Response) -> Optional[int]
+    try:
+        return int(resp.headers['content-length'])
+    except (ValueError, KeyError, TypeError):
+        return None
+
+
+def _prepare_download(
+    resp,  # type: Response
+    link,  # type: Link
+    progress_bar  # type: str
+):
+    # type: (...) -> Iterable[bytes]
+    total_length = _get_http_response_size(resp)
+
+    if link.netloc == PyPI.file_storage_domain:
+        url = link.show_url
+    else:
+        url = link.url_without_fragment
+
+    logged_url = redact_auth_from_url(url)
+
+    if total_length:
+        logged_url = '{} ({})'.format(logged_url, format_size(total_length))
+
+    if is_from_cache(resp):
+        logger.info("Using cached %s", logged_url)
+    else:
+        logger.info("Downloading %s", logged_url)
+
+    if logger.getEffectiveLevel() > logging.INFO:
+        show_progress = False
+    elif is_from_cache(resp):
+        show_progress = False
+    elif not total_length:
+        show_progress = True
+    elif total_length > (40 * 1000):
+        show_progress = True
+    else:
+        show_progress = False
+
+    chunks = response_chunks(resp, CONTENT_CHUNK_SIZE)
+
+    if not show_progress:
+        return chunks
+
+    return DownloadProgressProvider(
+        progress_bar, max=total_length
+    )(chunks)
+
+
+def sanitize_content_filename(filename):
+    # type: (str) -> str
+    """
+    Sanitize the "filename" value from a Content-Disposition header.
+    """
+    return os.path.basename(filename)
+
+
+def parse_content_disposition(content_disposition, default_filename):
+    # type: (str, str) -> str
+    """
+    Parse the "filename" value from a Content-Disposition header, and
+    return the default filename if the result is empty.
+    """
+    _type, params = cgi.parse_header(content_disposition)
+    filename = params.get('filename')
+    if filename:
+        # We need to sanitize the filename to prevent directory traversal
+        # in case the filename contains ".." path parts.
+        filename = sanitize_content_filename(filename)
+    return filename or default_filename
+
+
+def _get_http_response_filename(resp, link):
+    # type: (Response, Link) -> str
+    """Get an ideal filename from the given HTTP response, falling back to
+    the link filename if not provided.
+    """
+    filename = link.filename  # fallback
+    # Have a look at the Content-Disposition header for a better guess
+    content_disposition = resp.headers.get('content-disposition')
+    if content_disposition:
+        filename = parse_content_disposition(content_disposition, filename)
+    ext = splitext(filename)[1]  # type: Optional[str]
+    if not ext:
+        ext = mimetypes.guess_extension(
+            resp.headers.get('content-type', '')
+        )
+        if ext:
+            filename += ext
+    if not ext and link.url != resp.url:
+        ext = os.path.splitext(resp.url)[1]
+        if ext:
+            filename += ext
+    return filename
+
+
+def _http_get_download(session, link):
+    # type: (PipSession, Link) -> Response
+    target_url = link.url.split('#', 1)[0]
+    resp = session.get(
+        target_url,
+        # We use Accept-Encoding: identity here because requests
+        # defaults to accepting compressed responses. This breaks in
+        # a variety of ways depending on how the server is configured.
+        # - Some servers will notice that the file isn't a compressible
+        #   file and will leave the file alone and with an empty
+        #   Content-Encoding
+        # - Some servers will notice that the file is already
+        #   compressed and will leave the file alone and will add a
+        #   Content-Encoding: gzip header
+        # - Some servers won't notice anything at all and will take
+        #   a file that's already been compressed and compress it again
+        #   and set the Content-Encoding: gzip header
+        # By setting this to request only the identity encoding We're
+        # hoping to eliminate the third case. Hopefully there does not
+        # exist a server which when given a file will notice it is
+        # already compressed and that you're not asking for a
+        # compressed file and will then decompress it before sending
+        # because if that's the case I don't think it'll ever be
+        # possible to make this work.
+        headers={"Accept-Encoding": "identity"},
+        stream=True,
+    )
+    resp.raise_for_status()
+    return resp
+
+
+class Download(object):
+    def __init__(
+        self,
+        response,  # type: Response
+        filename,  # type: str
+        chunks,  # type: Iterable[bytes]
+    ):
+        # type: (...) -> None
+        self.response = response
+        self.filename = filename
+        self.chunks = chunks
+
+
+class Downloader(object):
+    def __init__(
+        self,
+        session,  # type: PipSession
+        progress_bar,  # type: str
+    ):
+        # type: (...) -> None
+        self._session = session
+        self._progress_bar = progress_bar
+
+    def __call__(self, link):
+        # type: (Link) -> Download
+        try:
+            resp = _http_get_download(self._session, link)
+        except requests.HTTPError as e:
+            logger.critical(
+                "HTTP error %s while getting %s", e.response.status_code, link
+            )
+            raise
+
+        return Download(
+            resp,
+            _get_http_response_filename(resp, link),
+            _prepare_download(resp, link, self._progress_bar),
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/session.py

@@ -0,0 +1,405 @@
+"""PipSession and supporting code, containing all pip-specific
+network request configuration and behavior.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import email.utils
+import json
+import logging
+import mimetypes
+import os
+import platform
+import sys
+import warnings
+
+from pip._vendor import requests, six, urllib3
+from pip._vendor.cachecontrol import CacheControlAdapter
+from pip._vendor.requests.adapters import BaseAdapter, HTTPAdapter
+from pip._vendor.requests.models import Response
+from pip._vendor.requests.structures import CaseInsensitiveDict
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.urllib3.exceptions import InsecureRequestWarning
+
+from pip import __version__
+from pip._internal.network.auth import MultiDomainBasicAuth
+from pip._internal.network.cache import SafeFileCache
+# Import ssl from compat so the initial import occurs in only one place.
+from pip._internal.utils.compat import has_tls, ipaddress
+from pip._internal.utils.glibc import libc_ver
+from pip._internal.utils.misc import (
+    build_url_from_netloc,
+    get_installed_version,
+    parse_netloc,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import url_to_path
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Iterator, List, Optional, Tuple, Union,
+    )
+
+    from pip._internal.models.link import Link
+
+    SecureOrigin = Tuple[str, str, Optional[Union[int, str]]]
+
+
+logger = logging.getLogger(__name__)
+
+
+# Ignore warning raised when using --trusted-host.
+warnings.filterwarnings("ignore", category=InsecureRequestWarning)
+
+
+SECURE_ORIGINS = [
+    # protocol, hostname, port
+    # Taken from Chrome's list of secure origins (See: http://bit.ly/1qrySKC)
+    ("https", "*", "*"),
+    ("*", "localhost", "*"),
+    ("*", "127.0.0.0/8", "*"),
+    ("*", "::1/128", "*"),
+    ("file", "*", None),
+    # ssh is always secure.
+    ("ssh", "*", "*"),
+]  # type: List[SecureOrigin]
+
+
+# These are environment variables present when running under various
+# CI systems.  For each variable, some CI systems that use the variable
+# are indicated.  The collection was chosen so that for each of a number
+# of popular systems, at least one of the environment variables is used.
+# This list is used to provide some indication of and lower bound for
+# CI traffic to PyPI.  Thus, it is okay if the list is not comprehensive.
+# For more background, see: https://github.com/pypa/pip/issues/5499
+CI_ENVIRONMENT_VARIABLES = (
+    # Azure Pipelines
+    'BUILD_BUILDID',
+    # Jenkins
+    'BUILD_ID',
+    # AppVeyor, CircleCI, Codeship, Gitlab CI, Shippable, Travis CI
+    'CI',
+    # Explicit environment variable.
+    'PIP_IS_CI',
+)
+
+
+def looks_like_ci():
+    # type: () -> bool
+    """
+    Return whether it looks like pip is running under CI.
+    """
+    # We don't use the method of checking for a tty (e.g. using isatty())
+    # because some CI systems mimic a tty (e.g. Travis CI).  Thus that
+    # method doesn't provide definitive information in either direction.
+    return any(name in os.environ for name in CI_ENVIRONMENT_VARIABLES)
+
+
+def user_agent():
+    """
+    Return a string representing the user agent.
+    """
+    data = {
+        "installer": {"name": "pip", "version": __version__},
+        "python": platform.python_version(),
+        "implementation": {
+            "name": platform.python_implementation(),
+        },
+    }
+
+    if data["implementation"]["name"] == 'CPython':
+        data["implementation"]["version"] = platform.python_version()
+    elif data["implementation"]["name"] == 'PyPy':
+        if sys.pypy_version_info.releaselevel == 'final':
+            pypy_version_info = sys.pypy_version_info[:3]
+        else:
+            pypy_version_info = sys.pypy_version_info
+        data["implementation"]["version"] = ".".join(
+            [str(x) for x in pypy_version_info]
+        )
+    elif data["implementation"]["name"] == 'Jython':
+        # Complete Guess
+        data["implementation"]["version"] = platform.python_version()
+    elif data["implementation"]["name"] == 'IronPython':
+        # Complete Guess
+        data["implementation"]["version"] = platform.python_version()
+
+    if sys.platform.startswith("linux"):
+        from pip._vendor import distro
+        distro_infos = dict(filter(
+            lambda x: x[1],
+            zip(["name", "version", "id"], distro.linux_distribution()),
+        ))
+        libc = dict(filter(
+            lambda x: x[1],
+            zip(["lib", "version"], libc_ver()),
+        ))
+        if libc:
+            distro_infos["libc"] = libc
+        if distro_infos:
+            data["distro"] = distro_infos
+
+    if sys.platform.startswith("darwin") and platform.mac_ver()[0]:
+        data["distro"] = {"name": "macOS", "version": platform.mac_ver()[0]}
+
+    if platform.system():
+        data.setdefault("system", {})["name"] = platform.system()
+
+    if platform.release():
+        data.setdefault("system", {})["release"] = platform.release()
+
+    if platform.machine():
+        data["cpu"] = platform.machine()
+
+    if has_tls():
+        import _ssl as ssl
+        data["openssl_version"] = ssl.OPENSSL_VERSION
+
+    setuptools_version = get_installed_version("setuptools")
+    if setuptools_version is not None:
+        data["setuptools_version"] = setuptools_version
+
+    # Use None rather than False so as not to give the impression that
+    # pip knows it is not being run under CI.  Rather, it is a null or
+    # inconclusive result.  Also, we include some value rather than no
+    # value to make it easier to know that the check has been run.
+    data["ci"] = True if looks_like_ci() else None
+
+    user_data = os.environ.get("PIP_USER_AGENT_USER_DATA")
+    if user_data is not None:
+        data["user_data"] = user_data
+
+    return "{data[installer][name]}/{data[installer][version]} {json}".format(
+        data=data,
+        json=json.dumps(data, separators=(",", ":"), sort_keys=True),
+    )
+
+
+class LocalFSAdapter(BaseAdapter):
+
+    def send(self, request, stream=None, timeout=None, verify=None, cert=None,
+             proxies=None):
+        pathname = url_to_path(request.url)
+
+        resp = Response()
+        resp.status_code = 200
+        resp.url = request.url
+
+        try:
+            stats = os.stat(pathname)
+        except OSError as exc:
+            resp.status_code = 404
+            resp.raw = exc
+        else:
+            modified = email.utils.formatdate(stats.st_mtime, usegmt=True)
+            content_type = mimetypes.guess_type(pathname)[0] or "text/plain"
+            resp.headers = CaseInsensitiveDict({
+                "Content-Type": content_type,
+                "Content-Length": stats.st_size,
+                "Last-Modified": modified,
+            })
+
+            resp.raw = open(pathname, "rb")
+            resp.close = resp.raw.close
+
+        return resp
+
+    def close(self):
+        pass
+
+
+class InsecureHTTPAdapter(HTTPAdapter):
+
+    def cert_verify(self, conn, url, verify, cert):
+        super(InsecureHTTPAdapter, self).cert_verify(
+            conn=conn, url=url, verify=False, cert=cert
+        )
+
+
+class PipSession(requests.Session):
+
+    timeout = None  # type: Optional[int]
+
+    def __init__(self, *args, **kwargs):
+        """
+        :param trusted_hosts: Domains not to emit warnings for when not using
+            HTTPS.
+        """
+        retries = kwargs.pop("retries", 0)
+        cache = kwargs.pop("cache", None)
+        trusted_hosts = kwargs.pop("trusted_hosts", [])  # type: List[str]
+        index_urls = kwargs.pop("index_urls", None)
+
+        super(PipSession, self).__init__(*args, **kwargs)
+
+        # Namespace the attribute with "pip_" just in case to prevent
+        # possible conflicts with the base class.
+        self.pip_trusted_origins = []  # type: List[Tuple[str, Optional[int]]]
+
+        # Attach our User Agent to the request
+        self.headers["User-Agent"] = user_agent()
+
+        # Attach our Authentication handler to the session
+        self.auth = MultiDomainBasicAuth(index_urls=index_urls)
+
+        # Create our urllib3.Retry instance which will allow us to customize
+        # how we handle retries.
+        retries = urllib3.Retry(
+            # Set the total number of retries that a particular request can
+            # have.
+            total=retries,
+
+            # A 503 error from PyPI typically means that the Fastly -> Origin
+            # connection got interrupted in some way. A 503 error in general
+            # is typically considered a transient error so we'll go ahead and
+            # retry it.
+            # A 500 may indicate transient error in Amazon S3
+            # A 520 or 527 - may indicate transient error in CloudFlare
+            status_forcelist=[500, 503, 520, 527],
+
+            # Add a small amount of back off between failed requests in
+            # order to prevent hammering the service.
+            backoff_factor=0.25,
+        )
+
+        # We want to _only_ cache responses on securely fetched origins. We do
+        # this because we can't validate the response of an insecurely fetched
+        # origin, and we don't want someone to be able to poison the cache and
+        # require manual eviction from the cache to fix it.
+        if cache:
+            secure_adapter = CacheControlAdapter(
+                cache=SafeFileCache(cache),
+                max_retries=retries,
+            )
+        else:
+            secure_adapter = HTTPAdapter(max_retries=retries)
+
+        # Our Insecure HTTPAdapter disables HTTPS validation. It does not
+        # support caching (see above) so we'll use it for all http:// URLs as
+        # well as any https:// host that we've marked as ignoring TLS errors
+        # for.
+        insecure_adapter = InsecureHTTPAdapter(max_retries=retries)
+        # Save this for later use in add_insecure_host().
+        self._insecure_adapter = insecure_adapter
+
+        self.mount("https://", secure_adapter)
+        self.mount("http://", insecure_adapter)
+
+        # Enable file:// urls
+        self.mount("file://", LocalFSAdapter())
+
+        for host in trusted_hosts:
+            self.add_trusted_host(host, suppress_logging=True)
+
+    def add_trusted_host(self, host, source=None, suppress_logging=False):
+        # type: (str, Optional[str], bool) -> None
+        """
+        :param host: It is okay to provide a host that has previously been
+            added.
+        :param source: An optional source string, for logging where the host
+            string came from.
+        """
+        if not suppress_logging:
+            msg = 'adding trusted host: {!r}'.format(host)
+            if source is not None:
+                msg += ' (from {})'.format(source)
+            logger.info(msg)
+
+        host_port = parse_netloc(host)
+        if host_port not in self.pip_trusted_origins:
+            self.pip_trusted_origins.append(host_port)
+
+        self.mount(build_url_from_netloc(host) + '/', self._insecure_adapter)
+        if not host_port[1]:
+            # Mount wildcard ports for the same host.
+            self.mount(
+                build_url_from_netloc(host) + ':',
+                self._insecure_adapter
+            )
+
+    def iter_secure_origins(self):
+        # type: () -> Iterator[SecureOrigin]
+        for secure_origin in SECURE_ORIGINS:
+            yield secure_origin
+        for host, port in self.pip_trusted_origins:
+            yield ('*', host, '*' if port is None else port)
+
+    def is_secure_origin(self, location):
+        # type: (Link) -> bool
+        # Determine if this url used a secure transport mechanism
+        parsed = urllib_parse.urlparse(str(location))
+        origin_protocol, origin_host, origin_port = (
+            parsed.scheme, parsed.hostname, parsed.port,
+        )
+
+        # The protocol to use to see if the protocol matches.
+        # Don't count the repository type as part of the protocol: in
+        # cases such as "git+ssh", only use "ssh". (I.e., Only verify against
+        # the last scheme.)
+        origin_protocol = origin_protocol.rsplit('+', 1)[-1]
+
+        # Determine if our origin is a secure origin by looking through our
+        # hardcoded list of secure origins, as well as any additional ones
+        # configured on this PackageFinder instance.
+        for secure_origin in self.iter_secure_origins():
+            secure_protocol, secure_host, secure_port = secure_origin
+            if origin_protocol != secure_protocol and secure_protocol != "*":
+                continue
+
+            try:
+                addr = ipaddress.ip_address(
+                    None
+                    if origin_host is None
+                    else six.ensure_text(origin_host)
+                )
+                network = ipaddress.ip_network(
+                    six.ensure_text(secure_host)
+                )
+            except ValueError:
+                # We don't have both a valid address or a valid network, so
+                # we'll check this origin against hostnames.
+                if (
+                    origin_host and
+                    origin_host.lower() != secure_host.lower() and
+                    secure_host != "*"
+                ):
+                    continue
+            else:
+                # We have a valid address and network, so see if the address
+                # is contained within the network.
+                if addr not in network:
+                    continue
+
+            # Check to see if the port matches.
+            if (
+                origin_port != secure_port and
+                secure_port != "*" and
+                secure_port is not None
+            ):
+                continue
+
+            # If we've gotten here, then this origin matches the current
+            # secure origin and we should return True
+            return True
+
+        # If we've gotten to this point, then the origin isn't secure and we
+        # will not accept it as a valid location to search. We will however
+        # log a warning that we are ignoring it.
+        logger.warning(
+            "The repository located at %s is not a trusted or secure host and "
+            "is being ignored. If this repository is available via HTTPS we "
+            "recommend you use HTTPS instead, otherwise you may silence "
+            "this warning and allow it anyway with '--trusted-host %s'.",
+            origin_host,
+            origin_host,
+        )
+
+        return False
+
+    def request(self, method, url, *args, **kwargs):
+        # Allow setting a default timeout on a session
+        kwargs.setdefault("timeout", self.timeout)
+
+        # Dispatch the actual request
+        return super(PipSession, self).request(method, url, *args, **kwargs)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/utils.py

@@ -0,0 +1,48 @@
+from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Iterator
+
+
+def response_chunks(response, chunk_size=CONTENT_CHUNK_SIZE):
+    # type: (Response, int) -> Iterator[bytes]
+    """Given a requests Response, provide the data chunks.
+    """
+    try:
+        # Special case for urllib3.
+        for chunk in response.raw.stream(
+            chunk_size,
+            # We use decode_content=False here because we don't
+            # want urllib3 to mess with the raw bytes we get
+            # from the server. If we decompress inside of
+            # urllib3 then we cannot verify the checksum
+            # because the checksum will be of the compressed
+            # file. This breakage will only occur if the
+            # server adds a Content-Encoding header, which
+            # depends on how the server was configured:
+            # - Some servers will notice that the file isn't a
+            #   compressible file and will leave the file alone
+            #   and with an empty Content-Encoding
+            # - Some servers will notice that the file is
+            #   already compressed and will leave the file
+            #   alone and will add a Content-Encoding: gzip
+            #   header
+            # - Some servers won't notice anything at all and
+            #   will take a file that's already been compressed
+            #   and compress it again and set the
+            #   Content-Encoding: gzip header
+            #
+            # By setting this not to decode automatically we
+            # hope to eliminate problems with the second case.
+            decode_content=False,
+        ):
+            yield chunk
+    except AttributeError:
+        # Standard file-like object.
+        while True:
+            chunk = response.raw.read(chunk_size)
+            if not chunk:
+                break
+            yield chunk

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/network/xmlrpc.py

@@ -0,0 +1,44 @@
+"""xmlrpclib.Transport implementation
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: disallow-untyped-defs=False
+
+import logging
+
+from pip._vendor import requests
+# NOTE: XMLRPC Client is not annotated in typeshed as on 2017-07-17, which is
+#       why we ignore the type on this import
+from pip._vendor.six.moves import xmlrpc_client  # type: ignore
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+logger = logging.getLogger(__name__)
+
+
+class PipXmlrpcTransport(xmlrpc_client.Transport):
+    """Provide a `xmlrpclib.Transport` implementation via a `PipSession`
+    object.
+    """
+
+    def __init__(self, index_url, session, use_datetime=False):
+        xmlrpc_client.Transport.__init__(self, use_datetime)
+        index_parts = urllib_parse.urlparse(index_url)
+        self._scheme = index_parts.scheme
+        self._session = session
+
+    def request(self, host, handler, request_body, verbose=False):
+        parts = (self._scheme, host, handler, None, None, None)
+        url = urllib_parse.urlunparse(parts)
+        try:
+            headers = {'Content-Type': 'text/xml'}
+            response = self._session.post(url, data=request_body,
+                                          headers=headers, stream=True)
+            response.raise_for_status()
+            self.verbose = verbose
+            return self.parse_response(response.raw)
+        except requests.HTTPError as exc:
+            logger.critical(
+                "HTTP error %s while getting %s",
+                exc.response.status_code, url,
+            )
+            raise

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/build/metadata.py

@@ -0,0 +1,40 @@
+"""Metadata generation logic for source distributions.
+"""
+
+import logging
+import os
+
+from pip._internal.utils.subprocess import runner_with_spinner_message
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from pip._internal.build_env import BuildEnvironment
+    from pip._vendor.pep517.wrappers import Pep517HookCaller
+
+logger = logging.getLogger(__name__)
+
+
+def generate_metadata(build_env, backend):
+    # type: (BuildEnvironment, Pep517HookCaller) -> str
+    """Generate metadata using mechanisms described in PEP 517.
+
+    Returns the generated metadata directory.
+    """
+    metadata_tmpdir = TempDirectory(
+        kind="modern-metadata", globally_managed=True
+    )
+
+    metadata_dir = metadata_tmpdir.path
+
+    with build_env:
+        # Note that Pep517HookCaller implements a fallback for
+        # prepare_metadata_for_build_wheel, so we don't have to
+        # consider the possibility that this hook doesn't exist.
+        runner = runner_with_spinner_message("Preparing wheel metadata")
+        with backend.subprocess_runner(runner):
+            distinfo_dir = backend.prepare_metadata_for_build_wheel(
+                metadata_dir
+            )
+
+    return os.path.join(metadata_dir, distinfo_dir)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/build/metadata_legacy.py

@@ -0,0 +1,122 @@
+"""Metadata generation logic for legacy source distributions.
+"""
+
+import logging
+import os
+
+from pip._internal.exceptions import InstallationError
+from pip._internal.utils.misc import ensure_dir
+from pip._internal.utils.setuptools_build import make_setuptools_egg_info_args
+from pip._internal.utils.subprocess import call_subprocess
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.vcs import vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional
+
+    from pip._internal.build_env import BuildEnvironment
+
+logger = logging.getLogger(__name__)
+
+
+def _find_egg_info(source_directory, is_editable):
+    # type: (str, bool) -> str
+    """Find an .egg-info in `source_directory`, based on `is_editable`.
+    """
+
+    def looks_like_virtual_env(path):
+        # type: (str) -> bool
+        return (
+            os.path.lexists(os.path.join(path, 'bin', 'python')) or
+            os.path.exists(os.path.join(path, 'Scripts', 'Python.exe'))
+        )
+
+    def locate_editable_egg_info(base):
+        # type: (str) -> List[str]
+        candidates = []  # type: List[str]
+        for root, dirs, files in os.walk(base):
+            for dir_ in vcs.dirnames:
+                if dir_ in dirs:
+                    dirs.remove(dir_)
+            # Iterate over a copy of ``dirs``, since mutating
+            # a list while iterating over it can cause trouble.
+            # (See https://github.com/pypa/pip/pull/462.)
+            for dir_ in list(dirs):
+                if looks_like_virtual_env(os.path.join(root, dir_)):
+                    dirs.remove(dir_)
+                # Also don't search through tests
+                elif dir_ == 'test' or dir_ == 'tests':
+                    dirs.remove(dir_)
+            candidates.extend(os.path.join(root, dir_) for dir_ in dirs)
+        return [f for f in candidates if f.endswith('.egg-info')]
+
+    def depth_of_directory(dir_):
+        # type: (str) -> int
+        return (
+            dir_.count(os.path.sep) +
+            (os.path.altsep and dir_.count(os.path.altsep) or 0)
+        )
+
+    base = source_directory
+    if is_editable:
+        filenames = locate_editable_egg_info(base)
+    else:
+        base = os.path.join(base, 'pip-egg-info')
+        filenames = os.listdir(base)
+
+    if not filenames:
+        raise InstallationError(
+            "Files/directories not found in {}".format(base)
+        )
+
+    # If we have more than one match, we pick the toplevel one.  This
+    # can easily be the case if there is a dist folder which contains
+    # an extracted tarball for testing purposes.
+    if len(filenames) > 1:
+        filenames.sort(key=depth_of_directory)
+
+    return os.path.join(base, filenames[0])
+
+
+def generate_metadata(
+    build_env,  # type: BuildEnvironment
+    setup_py_path,  # type: str
+    source_dir,  # type: str
+    editable,  # type: bool
+    isolated,  # type: bool
+    details,  # type: str
+):
+    # type: (...) -> str
+    """Generate metadata using setup.py-based defacto mechanisms.
+
+    Returns the generated metadata directory.
+    """
+    logger.debug(
+        'Running setup.py (path:%s) egg_info for package %s',
+        setup_py_path, details,
+    )
+
+    egg_info_dir = None  # type: Optional[str]
+    # For non-editable installs, don't put the .egg-info files at the root,
+    # to avoid confusion due to the source code being considered an installed
+    # egg.
+    if not editable:
+        egg_info_dir = os.path.join(source_dir, 'pip-egg-info')
+        # setuptools complains if the target directory does not exist.
+        ensure_dir(egg_info_dir)
+
+    args = make_setuptools_egg_info_args(
+        setup_py_path,
+        egg_info_dir=egg_info_dir,
+        no_user_config=isolated,
+    )
+
+    with build_env:
+        call_subprocess(
+            args,
+            cwd=source_dir,
+            command_desc='python setup.py egg_info',
+        )
+
+    # Return the .egg-info directory.
+    return _find_egg_info(source_dir, editable)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/build/wheel.py

@@ -0,0 +1,46 @@
+import logging
+import os
+
+from pip._internal.utils.subprocess import runner_with_spinner_message
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional
+    from pip._vendor.pep517.wrappers import Pep517HookCaller
+
+logger = logging.getLogger(__name__)
+
+
+def build_wheel_pep517(
+    name,  # type: str
+    backend,  # type: Pep517HookCaller
+    metadata_directory,  # type: str
+    build_options,  # type: List[str]
+    tempd,  # type: str
+):
+    # type: (...) -> Optional[str]
+    """Build one InstallRequirement using the PEP 517 build process.
+
+    Returns path to wheel if successfully built. Otherwise, returns None.
+    """
+    assert metadata_directory is not None
+    if build_options:
+        # PEP 517 does not support --build-options
+        logger.error('Cannot build wheel for %s using PEP 517 when '
+                     '--build-option is present' % (name,))
+        return None
+    try:
+        logger.debug('Destination directory: %s', tempd)
+
+        runner = runner_with_spinner_message(
+            'Building wheel for {} (PEP 517)'.format(name)
+        )
+        with backend.subprocess_runner(runner):
+            wheel_name = backend.build_wheel(
+                tempd,
+                metadata_directory=metadata_directory,
+            )
+    except Exception:
+        logger.error('Failed building wheel for %s', name)
+        return None
+    return os.path.join(tempd, wheel_name)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/build/wheel_legacy.py

@@ -0,0 +1,115 @@
+import logging
+import os.path
+
+from pip._internal.utils.setuptools_build import (
+    make_setuptools_bdist_wheel_args,
+)
+from pip._internal.utils.subprocess import (
+    LOG_DIVIDER,
+    call_subprocess,
+    format_command_args,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import open_spinner
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional, Text
+
+logger = logging.getLogger(__name__)
+
+
+def format_command_result(
+    command_args,  # type: List[str]
+    command_output,  # type: Text
+):
+    # type: (...) -> str
+    """Format command information for logging."""
+    command_desc = format_command_args(command_args)
+    text = 'Command arguments: {}\n'.format(command_desc)
+
+    if not command_output:
+        text += 'Command output: None'
+    elif logger.getEffectiveLevel() > logging.DEBUG:
+        text += 'Command output: [use --verbose to show]'
+    else:
+        if not command_output.endswith('\n'):
+            command_output += '\n'
+        text += 'Command output:\n{}{}'.format(command_output, LOG_DIVIDER)
+
+    return text
+
+
+def get_legacy_build_wheel_path(
+    names,  # type: List[str]
+    temp_dir,  # type: str
+    name,  # type: str
+    command_args,  # type: List[str]
+    command_output,  # type: Text
+):
+    # type: (...) -> Optional[str]
+    """Return the path to the wheel in the temporary build directory."""
+    # Sort for determinism.
+    names = sorted(names)
+    if not names:
+        msg = (
+            'Legacy build of wheel for {!r} created no files.\n'
+        ).format(name)
+        msg += format_command_result(command_args, command_output)
+        logger.warning(msg)
+        return None
+
+    if len(names) > 1:
+        msg = (
+            'Legacy build of wheel for {!r} created more than one file.\n'
+            'Filenames (choosing first): {}\n'
+        ).format(name, names)
+        msg += format_command_result(command_args, command_output)
+        logger.warning(msg)
+
+    return os.path.join(temp_dir, names[0])
+
+
+def build_wheel_legacy(
+    name,  # type: str
+    setup_py_path,  # type: str
+    source_dir,  # type: str
+    global_options,  # type: List[str]
+    build_options,  # type: List[str]
+    tempd,  # type: str
+):
+    # type: (...) -> Optional[str]
+    """Build one unpacked package using the "legacy" build process.
+
+    Returns path to wheel if successfully built. Otherwise, returns None.
+    """
+    wheel_args = make_setuptools_bdist_wheel_args(
+        setup_py_path,
+        global_options=global_options,
+        build_options=build_options,
+        destination_dir=tempd,
+    )
+
+    spin_message = 'Building wheel for %s (setup.py)' % (name,)
+    with open_spinner(spin_message) as spinner:
+        logger.debug('Destination directory: %s', tempd)
+
+        try:
+            output = call_subprocess(
+                wheel_args,
+                cwd=source_dir,
+                spinner=spinner,
+            )
+        except Exception:
+            spinner.finish("error")
+            logger.error('Failed building wheel for %s', name)
+            return None
+
+        names = os.listdir(tempd)
+        wheel_path = get_legacy_build_wheel_path(
+            names=names,
+            temp_dir=tempd,
+            name=name,
+            command_args=wheel_args,
+            command_output=output,
+        )
+        return wheel_path

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/check.py

@@ -0,0 +1,163 @@
+"""Validation of dependencies of packages
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+import logging
+from collections import namedtuple
+
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.pkg_resources import RequirementParseError
+
+from pip._internal.distributions import (
+    make_distribution_for_install_requirement,
+)
+from pip._internal.utils.misc import get_installed_distributions
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+logger = logging.getLogger(__name__)
+
+if MYPY_CHECK_RUNNING:
+    from pip._internal.req.req_install import InstallRequirement
+    from typing import (
+        Any, Callable, Dict, Optional, Set, Tuple, List
+    )
+
+    # Shorthands
+    PackageSet = Dict[str, 'PackageDetails']
+    Missing = Tuple[str, Any]
+    Conflicting = Tuple[str, str, Any]
+
+    MissingDict = Dict[str, List[Missing]]
+    ConflictingDict = Dict[str, List[Conflicting]]
+    CheckResult = Tuple[MissingDict, ConflictingDict]
+
+PackageDetails = namedtuple('PackageDetails', ['version', 'requires'])
+
+
+def create_package_set_from_installed(**kwargs):
+    # type: (**Any) -> Tuple[PackageSet, bool]
+    """Converts a list of distributions into a PackageSet.
+    """
+    # Default to using all packages installed on the system
+    if kwargs == {}:
+        kwargs = {"local_only": False, "skip": ()}
+
+    package_set = {}
+    problems = False
+    for dist in get_installed_distributions(**kwargs):
+        name = canonicalize_name(dist.project_name)
+        try:
+            package_set[name] = PackageDetails(dist.version, dist.requires())
+        except RequirementParseError as e:
+            # Don't crash on broken metadata
+            logger.warning("Error parsing requirements for %s: %s", name, e)
+            problems = True
+    return package_set, problems
+
+
+def check_package_set(package_set, should_ignore=None):
+    # type: (PackageSet, Optional[Callable[[str], bool]]) -> CheckResult
+    """Check if a package set is consistent
+
+    If should_ignore is passed, it should be a callable that takes a
+    package name and returns a boolean.
+    """
+    if should_ignore is None:
+        def should_ignore(name):
+            return False
+
+    missing = {}
+    conflicting = {}
+
+    for package_name in package_set:
+        # Info about dependencies of package_name
+        missing_deps = set()  # type: Set[Missing]
+        conflicting_deps = set()  # type: Set[Conflicting]
+
+        if should_ignore(package_name):
+            continue
+
+        for req in package_set[package_name].requires:
+            name = canonicalize_name(req.project_name)  # type: str
+
+            # Check if it's missing
+            if name not in package_set:
+                missed = True
+                if req.marker is not None:
+                    missed = req.marker.evaluate()
+                if missed:
+                    missing_deps.add((name, req))
+                continue
+
+            # Check if there's a conflict
+            version = package_set[name].version  # type: str
+            if not req.specifier.contains(version, prereleases=True):
+                conflicting_deps.add((name, version, req))
+
+        if missing_deps:
+            missing[package_name] = sorted(missing_deps, key=str)
+        if conflicting_deps:
+            conflicting[package_name] = sorted(conflicting_deps, key=str)
+
+    return missing, conflicting
+
+
+def check_install_conflicts(to_install):
+    # type: (List[InstallRequirement]) -> Tuple[PackageSet, CheckResult]
+    """For checking if the dependency graph would be consistent after \
+    installing given requirements
+    """
+    # Start from the current state
+    package_set, _ = create_package_set_from_installed()
+    # Install packages
+    would_be_installed = _simulate_installation_of(to_install, package_set)
+
+    # Only warn about directly-dependent packages; create a whitelist of them
+    whitelist = _create_whitelist(would_be_installed, package_set)
+
+    return (
+        package_set,
+        check_package_set(
+            package_set, should_ignore=lambda name: name not in whitelist
+        )
+    )
+
+
+def _simulate_installation_of(to_install, package_set):
+    # type: (List[InstallRequirement], PackageSet) -> Set[str]
+    """Computes the version of packages after installing to_install.
+    """
+
+    # Keep track of packages that were installed
+    installed = set()
+
+    # Modify it as installing requirement_set would (assuming no errors)
+    for inst_req in to_install:
+        abstract_dist = make_distribution_for_install_requirement(inst_req)
+        dist = abstract_dist.get_pkg_resources_distribution()
+
+        name = canonicalize_name(dist.key)
+        package_set[name] = PackageDetails(dist.version, dist.requires())
+
+        installed.add(name)
+
+    return installed
+
+
+def _create_whitelist(would_be_installed, package_set):
+    # type: (Set[str], PackageSet) -> Set[str]
+    packages_affected = set(would_be_installed)
+
+    for package_name in package_set:
+        if package_name in packages_affected:
+            continue
+
+        for req in package_set[package_name].requires:
+            if canonicalize_name(req.name) in packages_affected:
+                packages_affected.add(package_name)
+                break
+
+    return packages_affected

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/freeze.py

@@ -0,0 +1,265 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+# mypy: disallow-untyped-defs=False
+
+from __future__ import absolute_import
+
+import collections
+import logging
+import os
+import re
+
+from pip._vendor import six
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.pkg_resources import RequirementParseError
+
+from pip._internal.exceptions import BadCommand, InstallationError
+from pip._internal.req.constructors import (
+    install_req_from_editable,
+    install_req_from_line,
+)
+from pip._internal.req.req_file import COMMENT_RE
+from pip._internal.utils.misc import (
+    dist_is_editable,
+    get_installed_distributions,
+)
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Iterator, Optional, List, Container, Set, Dict, Tuple, Iterable, Union
+    )
+    from pip._internal.cache import WheelCache
+    from pip._vendor.pkg_resources import (
+        Distribution, Requirement
+    )
+
+    RequirementInfo = Tuple[Optional[Union[str, Requirement]], bool, List[str]]
+
+
+logger = logging.getLogger(__name__)
+
+
+def freeze(
+    requirement=None,  # type: Optional[List[str]]
+    find_links=None,  # type: Optional[List[str]]
+    local_only=None,  # type: Optional[bool]
+    user_only=None,  # type: Optional[bool]
+    paths=None,  # type: Optional[List[str]]
+    skip_regex=None,  # type: Optional[str]
+    isolated=False,  # type: bool
+    wheel_cache=None,  # type: Optional[WheelCache]
+    exclude_editable=False,  # type: bool
+    skip=()  # type: Container[str]
+):
+    # type: (...) -> Iterator[str]
+    find_links = find_links or []
+    skip_match = None
+
+    if skip_regex:
+        skip_match = re.compile(skip_regex).search
+
+    for link in find_links:
+        yield '-f %s' % link
+    installations = {}  # type: Dict[str, FrozenRequirement]
+    for dist in get_installed_distributions(local_only=local_only,
+                                            skip=(),
+                                            user_only=user_only,
+                                            paths=paths):
+        try:
+            req = FrozenRequirement.from_dist(dist)
+        except RequirementParseError as exc:
+            # We include dist rather than dist.project_name because the
+            # dist string includes more information, like the version and
+            # location. We also include the exception message to aid
+            # troubleshooting.
+            logger.warning(
+                'Could not generate requirement for distribution %r: %s',
+                dist, exc
+            )
+            continue
+        if exclude_editable and req.editable:
+            continue
+        installations[req.canonical_name] = req
+
+    if requirement:
+        # the options that don't get turned into an InstallRequirement
+        # should only be emitted once, even if the same option is in multiple
+        # requirements files, so we need to keep track of what has been emitted
+        # so that we don't emit it again if it's seen again
+        emitted_options = set()  # type: Set[str]
+        # keep track of which files a requirement is in so that we can
+        # give an accurate warning if a requirement appears multiple times.
+        req_files = collections.defaultdict(list)  # type: Dict[str, List[str]]
+        for req_file_path in requirement:
+            with open(req_file_path) as req_file:
+                for line in req_file:
+                    if (not line.strip() or
+                            line.strip().startswith('#') or
+                            (skip_match and skip_match(line)) or
+                            line.startswith((
+                                '-r', '--requirement',
+                                '-Z', '--always-unzip',
+                                '-f', '--find-links',
+                                '-i', '--index-url',
+                                '--pre',
+                                '--trusted-host',
+                                '--process-dependency-links',
+                                '--extra-index-url'))):
+                        line = line.rstrip()
+                        if line not in emitted_options:
+                            emitted_options.add(line)
+                            yield line
+                        continue
+
+                    if line.startswith('-e') or line.startswith('--editable'):
+                        if line.startswith('-e'):
+                            line = line[2:].strip()
+                        else:
+                            line = line[len('--editable'):].strip().lstrip('=')
+                        line_req = install_req_from_editable(
+                            line,
+                            isolated=isolated,
+                            wheel_cache=wheel_cache,
+                        )
+                    else:
+                        line_req = install_req_from_line(
+                            COMMENT_RE.sub('', line).strip(),
+                            isolated=isolated,
+                            wheel_cache=wheel_cache,
+                        )
+
+                    if not line_req.name:
+                        logger.info(
+                            "Skipping line in requirement file [%s] because "
+                            "it's not clear what it would install: %s",
+                            req_file_path, line.strip(),
+                        )
+                        logger.info(
+                            "  (add #egg=PackageName to the URL to avoid"
+                            " this warning)"
+                        )
+                    else:
+                        line_req_canonical_name = canonicalize_name(
+                            line_req.name)
+                        if line_req_canonical_name not in installations:
+                            # either it's not installed, or it is installed
+                            # but has been processed already
+                            if not req_files[line_req.name]:
+                                logger.warning(
+                                    "Requirement file [%s] contains %s, but "
+                                    "package %r is not installed",
+                                    req_file_path,
+                                    COMMENT_RE.sub('', line).strip(),
+                                    line_req.name
+                                )
+                            else:
+                                req_files[line_req.name].append(req_file_path)
+                        else:
+                            yield str(installations[
+                                line_req_canonical_name]).rstrip()
+                            del installations[line_req_canonical_name]
+                            req_files[line_req.name].append(req_file_path)
+
+        # Warn about requirements that were included multiple times (in a
+        # single requirements file or in different requirements files).
+        for name, files in six.iteritems(req_files):
+            if len(files) > 1:
+                logger.warning("Requirement %s included multiple times [%s]",
+                               name, ', '.join(sorted(set(files))))
+
+        yield(
+            '## The following requirements were added by '
+            'pip freeze:'
+        )
+    for installation in sorted(
+            installations.values(), key=lambda x: x.name.lower()):
+        if installation.canonical_name not in skip:
+            yield str(installation).rstrip()
+
+
+def get_requirement_info(dist):
+    # type: (Distribution) -> RequirementInfo
+    """
+    Compute and return values (req, editable, comments) for use in
+    FrozenRequirement.from_dist().
+    """
+    if not dist_is_editable(dist):
+        return (None, False, [])
+
+    location = os.path.normcase(os.path.abspath(dist.location))
+
+    from pip._internal.vcs import vcs, RemoteNotFoundError
+    vcs_backend = vcs.get_backend_for_dir(location)
+
+    if vcs_backend is None:
+        req = dist.as_requirement()
+        logger.debug(
+            'No VCS found for editable requirement "%s" in: %r', req,
+            location,
+        )
+        comments = [
+            '# Editable install with no version control ({})'.format(req)
+        ]
+        return (location, True, comments)
+
+    try:
+        req = vcs_backend.get_src_requirement(location, dist.project_name)
+    except RemoteNotFoundError:
+        req = dist.as_requirement()
+        comments = [
+            '# Editable {} install with no remote ({})'.format(
+                type(vcs_backend).__name__, req,
+            )
+        ]
+        return (location, True, comments)
+
+    except BadCommand:
+        logger.warning(
+            'cannot determine version of editable source in %s '
+            '(%s command not found in path)',
+            location,
+            vcs_backend.name,
+        )
+        return (None, True, [])
+
+    except InstallationError as exc:
+        logger.warning(
+            "Error when trying to get requirement for VCS system %s, "
+            "falling back to uneditable format", exc
+        )
+    else:
+        if req is not None:
+            return (req, True, [])
+
+    logger.warning(
+        'Could not determine repository location of %s', location
+    )
+    comments = ['## !! Could not determine repository location']
+
+    return (None, False, comments)
+
+
+class FrozenRequirement(object):
+    def __init__(self, name, req, editable, comments=()):
+        # type: (str, Union[str, Requirement], bool, Iterable[str]) -> None
+        self.name = name
+        self.canonical_name = canonicalize_name(name)
+        self.req = req
+        self.editable = editable
+        self.comments = comments
+
+    @classmethod
+    def from_dist(cls, dist):
+        # type: (Distribution) -> FrozenRequirement
+        req, editable, comments = get_requirement_info(dist)
+        if req is None:
+            req = dist.as_requirement()
+
+        return cls(dist.project_name, req, editable, comments=comments)
+
+    def __str__(self):
+        req = self.req
+        if self.editable:
+            req = '-e %s' % req
+        return '\n'.join(list(self.comments) + [str(req)]) + '\n'

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/install/__init__.py

@@ -0,0 +1,2 @@
+"""For modules related to installing packages.
+"""

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/install/editable_legacy.py

@@ -0,0 +1,52 @@
+"""Legacy editable installation process, i.e. `setup.py develop`.
+"""
+import logging
+
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.setuptools_build import make_setuptools_develop_args
+from pip._internal.utils.subprocess import call_subprocess
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional, Sequence
+
+    from pip._internal.build_env import BuildEnvironment
+
+
+logger = logging.getLogger(__name__)
+
+
+def install_editable(
+    install_options,  # type: List[str]
+    global_options,  # type: Sequence[str]
+    prefix,  # type: Optional[str]
+    home,  # type: Optional[str]
+    use_user_site,  # type: bool
+    name,  # type: str
+    setup_py_path,  # type: str
+    isolated,  # type: bool
+    build_env,  # type: BuildEnvironment
+    unpacked_source_directory,  # type: str
+):
+    # type: (...) -> None
+    """Install a package in editable mode. Most arguments are pass-through
+    to setuptools.
+    """
+    logger.info('Running setup.py develop for %s', name)
+
+    args = make_setuptools_develop_args(
+        setup_py_path,
+        global_options=global_options,
+        install_options=install_options,
+        no_user_config=isolated,
+        prefix=prefix,
+        home=home,
+        use_user_site=use_user_site,
+    )
+
+    with indent_log():
+        with build_env:
+            call_subprocess(
+                args,
+                cwd=unpacked_source_directory,
+            )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/install/legacy.py

@@ -0,0 +1,129 @@
+"""Legacy installation process, i.e. `setup.py install`.
+"""
+
+import logging
+import os
+from distutils.util import change_root
+
+from pip._internal.utils.deprecation import deprecated
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.misc import ensure_dir
+from pip._internal.utils.setuptools_build import make_setuptools_install_args
+from pip._internal.utils.subprocess import runner_with_spinner_message
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional, Sequence
+
+    from pip._internal.models.scheme import Scheme
+    from pip._internal.req.req_install import InstallRequirement
+
+
+logger = logging.getLogger(__name__)
+
+
+def install(
+    install_req,  # type: InstallRequirement
+    install_options,  # type: List[str]
+    global_options,  # type: Sequence[str]
+    root,  # type: Optional[str]
+    home,  # type: Optional[str]
+    prefix,  # type: Optional[str]
+    use_user_site,  # type: bool
+    pycompile,  # type: bool
+    scheme,  # type: Scheme
+):
+    # type: (...) -> None
+    # Extend the list of global and install options passed on to
+    # the setup.py call with the ones from the requirements file.
+    # Options specified in requirements file override those
+    # specified on the command line, since the last option given
+    # to setup.py is the one that is used.
+    global_options = list(global_options) + \
+        install_req.options.get('global_options', [])
+    install_options = list(install_options) + \
+        install_req.options.get('install_options', [])
+
+    header_dir = scheme.headers
+
+    with TempDirectory(kind="record") as temp_dir:
+        record_filename = os.path.join(temp_dir.path, 'install-record.txt')
+        install_args = make_setuptools_install_args(
+            install_req.setup_py_path,
+            global_options=global_options,
+            install_options=install_options,
+            record_filename=record_filename,
+            root=root,
+            prefix=prefix,
+            header_dir=header_dir,
+            home=home,
+            use_user_site=use_user_site,
+            no_user_config=install_req.isolated,
+            pycompile=pycompile,
+        )
+
+        runner = runner_with_spinner_message(
+            "Running setup.py install for {}".format(install_req.name)
+        )
+        with indent_log(), install_req.build_env:
+            runner(
+                cmd=install_args,
+                cwd=install_req.unpacked_source_directory,
+            )
+
+        if not os.path.exists(record_filename):
+            logger.debug('Record file %s not found', record_filename)
+            return
+        install_req.install_succeeded = True
+
+        # We intentionally do not use any encoding to read the file because
+        # setuptools writes the file using distutils.file_util.write_file,
+        # which does not specify an encoding.
+        with open(record_filename) as f:
+            record_lines = f.read().splitlines()
+
+    def prepend_root(path):
+        # type: (str) -> str
+        if root is None or not os.path.isabs(path):
+            return path
+        else:
+            return change_root(root, path)
+
+    for line in record_lines:
+        directory = os.path.dirname(line)
+        if directory.endswith('.egg-info'):
+            egg_info_dir = prepend_root(directory)
+            break
+    else:
+        deprecated(
+            reason=(
+                "{} did not indicate that it installed an "
+                ".egg-info directory. Only setup.py projects "
+                "generating .egg-info directories are supported."
+            ).format(install_req),
+            replacement=(
+                "for maintainers: updating the setup.py of {0}. "
+                "For users: contact the maintainers of {0} to let "
+                "them know to update their setup.py.".format(
+                    install_req.name
+                )
+            ),
+            gone_in="20.2",
+            issue=6998,
+        )
+        # FIXME: put the record somewhere
+        return
+    new_lines = []
+    for line in record_lines:
+        filename = line.strip()
+        if os.path.isdir(filename):
+            filename += os.path.sep
+        new_lines.append(
+            os.path.relpath(prepend_root(filename), egg_info_dir)
+        )
+    new_lines.sort()
+    ensure_dir(egg_info_dir)
+    inst_files_path = os.path.join(egg_info_dir, 'installed-files.txt')
+    with open(inst_files_path, 'w') as f:
+        f.write('\n'.join(new_lines) + '\n')

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/install/wheel.py

@@ -0,0 +1,615 @@
+"""Support for installing and building the "wheel" binary package format.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import collections
+import compileall
+import csv
+import logging
+import os.path
+import re
+import shutil
+import stat
+import sys
+import warnings
+from base64 import urlsafe_b64encode
+from zipfile import ZipFile
+
+from pip._vendor import pkg_resources
+from pip._vendor.distlib.scripts import ScriptMaker
+from pip._vendor.distlib.util import get_export_entry
+from pip._vendor.six import StringIO
+
+from pip._internal.exceptions import InstallationError
+from pip._internal.locations import get_major_minor_version
+from pip._internal.utils.misc import captured_stdout, ensure_dir, hash_file
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.unpacking import unpack_file
+from pip._internal.utils.wheel import parse_wheel
+
+if MYPY_CHECK_RUNNING:
+    from email.message import Message
+    from typing import (
+        Dict, List, Optional, Sequence, Tuple, IO, Text, Any,
+        Iterable, Callable, Set,
+    )
+
+    from pip._internal.models.scheme import Scheme
+
+    InstalledCSVRow = Tuple[str, ...]
+
+
+logger = logging.getLogger(__name__)
+
+
+def normpath(src, p):
+    # type: (str, str) -> str
+    return os.path.relpath(src, p).replace(os.path.sep, '/')
+
+
+def rehash(path, blocksize=1 << 20):
+    # type: (str, int) -> Tuple[str, str]
+    """Return (encoded_digest, length) for path using hashlib.sha256()"""
+    h, length = hash_file(path, blocksize)
+    digest = 'sha256=' + urlsafe_b64encode(
+        h.digest()
+    ).decode('latin1').rstrip('=')
+    # unicode/str python2 issues
+    return (digest, str(length))  # type: ignore
+
+
+def open_for_csv(name, mode):
+    # type: (str, Text) -> IO[Any]
+    if sys.version_info[0] < 3:
+        nl = {}  # type: Dict[str, Any]
+        bin = 'b'
+    else:
+        nl = {'newline': ''}  # type: Dict[str, Any]
+        bin = ''
+    return open(name, mode + bin, **nl)
+
+
+def fix_script(path):
+    # type: (str) -> Optional[bool]
+    """Replace #!python with #!/path/to/python
+    Return True if file was changed.
+    """
+    # XXX RECORD hashes will need to be updated
+    if os.path.isfile(path):
+        with open(path, 'rb') as script:
+            firstline = script.readline()
+            if not firstline.startswith(b'#!python'):
+                return False
+            exename = sys.executable.encode(sys.getfilesystemencoding())
+            firstline = b'#!' + exename + os.linesep.encode("ascii")
+            rest = script.read()
+        with open(path, 'wb') as script:
+            script.write(firstline)
+            script.write(rest)
+        return True
+    return None
+
+
+def wheel_root_is_purelib(metadata):
+    # type: (Message) -> bool
+    return metadata.get("Root-Is-Purelib", "").lower() == "true"
+
+
+def get_entrypoints(filename):
+    # type: (str) -> Tuple[Dict[str, str], Dict[str, str]]
+    if not os.path.exists(filename):
+        return {}, {}
+
+    # This is done because you can pass a string to entry_points wrappers which
+    # means that they may or may not be valid INI files. The attempt here is to
+    # strip leading and trailing whitespace in order to make them valid INI
+    # files.
+    with open(filename) as fp:
+        data = StringIO()
+        for line in fp:
+            data.write(line.strip())
+            data.write("\n")
+        data.seek(0)
+
+    # get the entry points and then the script names
+    entry_points = pkg_resources.EntryPoint.parse_map(data)
+    console = entry_points.get('console_scripts', {})
+    gui = entry_points.get('gui_scripts', {})
+
+    def _split_ep(s):
+        # type: (pkg_resources.EntryPoint) -> Tuple[str, str]
+        """get the string representation of EntryPoint,
+        remove space and split on '='
+        """
+        split_parts = str(s).replace(" ", "").split("=")
+        return split_parts[0], split_parts[1]
+
+    # convert the EntryPoint objects into strings with module:function
+    console = dict(_split_ep(v) for v in console.values())
+    gui = dict(_split_ep(v) for v in gui.values())
+    return console, gui
+
+
+def message_about_scripts_not_on_PATH(scripts):
+    # type: (Sequence[str]) -> Optional[str]
+    """Determine if any scripts are not on PATH and format a warning.
+    Returns a warning message if one or more scripts are not on PATH,
+    otherwise None.
+    """
+    if not scripts:
+        return None
+
+    # Group scripts by the path they were installed in
+    grouped_by_dir = collections.defaultdict(set)  # type: Dict[str, Set[str]]
+    for destfile in scripts:
+        parent_dir = os.path.dirname(destfile)
+        script_name = os.path.basename(destfile)
+        grouped_by_dir[parent_dir].add(script_name)
+
+    # We don't want to warn for directories that are on PATH.
+    not_warn_dirs = [
+        os.path.normcase(i).rstrip(os.sep) for i in
+        os.environ.get("PATH", "").split(os.pathsep)
+    ]
+    # If an executable sits with sys.executable, we don't warn for it.
+    #     This covers the case of venv invocations without activating the venv.
+    not_warn_dirs.append(os.path.normcase(os.path.dirname(sys.executable)))
+    warn_for = {
+        parent_dir: scripts for parent_dir, scripts in grouped_by_dir.items()
+        if os.path.normcase(parent_dir) not in not_warn_dirs
+    }  # type: Dict[str, Set[str]]
+    if not warn_for:
+        return None
+
+    # Format a message
+    msg_lines = []
+    for parent_dir, dir_scripts in warn_for.items():
+        sorted_scripts = sorted(dir_scripts)  # type: List[str]
+        if len(sorted_scripts) == 1:
+            start_text = "script {} is".format(sorted_scripts[0])
+        else:
+            start_text = "scripts {} are".format(
+                ", ".join(sorted_scripts[:-1]) + " and " + sorted_scripts[-1]
+            )
+
+        msg_lines.append(
+            "The {} installed in '{}' which is not on PATH."
+            .format(start_text, parent_dir)
+        )
+
+    last_line_fmt = (
+        "Consider adding {} to PATH or, if you prefer "
+        "to suppress this warning, use --no-warn-script-location."
+    )
+    if len(msg_lines) == 1:
+        msg_lines.append(last_line_fmt.format("this directory"))
+    else:
+        msg_lines.append(last_line_fmt.format("these directories"))
+
+    # Add a note if any directory starts with ~
+    warn_for_tilde = any(
+        i[0] == "~" for i in os.environ.get("PATH", "").split(os.pathsep) if i
+    )
+    if warn_for_tilde:
+        tilde_warning_msg = (
+            "NOTE: The current PATH contains path(s) starting with `~`, "
+            "which may not be expanded by all applications."
+        )
+        msg_lines.append(tilde_warning_msg)
+
+    # Returns the formatted multiline message
+    return "\n".join(msg_lines)
+
+
+def sorted_outrows(outrows):
+    # type: (Iterable[InstalledCSVRow]) -> List[InstalledCSVRow]
+    """Return the given rows of a RECORD file in sorted order.
+
+    Each row is a 3-tuple (path, hash, size) and corresponds to a record of
+    a RECORD file (see PEP 376 and PEP 427 for details).  For the rows
+    passed to this function, the size can be an integer as an int or string,
+    or the empty string.
+    """
+    # Normally, there should only be one row per path, in which case the
+    # second and third elements don't come into play when sorting.
+    # However, in cases in the wild where a path might happen to occur twice,
+    # we don't want the sort operation to trigger an error (but still want
+    # determinism).  Since the third element can be an int or string, we
+    # coerce each element to a string to avoid a TypeError in this case.
+    # For additional background, see--
+    # https://github.com/pypa/pip/issues/5868
+    return sorted(outrows, key=lambda row: tuple(str(x) for x in row))
+
+
+def get_csv_rows_for_installed(
+    old_csv_rows,  # type: Iterable[List[str]]
+    installed,  # type: Dict[str, str]
+    changed,  # type: Set[str]
+    generated,  # type: List[str]
+    lib_dir,  # type: str
+):
+    # type: (...) -> List[InstalledCSVRow]
+    """
+    :param installed: A map from archive RECORD path to installation RECORD
+        path.
+    """
+    installed_rows = []  # type: List[InstalledCSVRow]
+    for row in old_csv_rows:
+        if len(row) > 3:
+            logger.warning(
+                'RECORD line has more than three elements: {}'.format(row)
+            )
+        # Make a copy because we are mutating the row.
+        row = list(row)
+        old_path = row[0]
+        new_path = installed.pop(old_path, old_path)
+        row[0] = new_path
+        if new_path in changed:
+            digest, length = rehash(new_path)
+            row[1] = digest
+            row[2] = length
+        installed_rows.append(tuple(row))
+    for f in generated:
+        digest, length = rehash(f)
+        installed_rows.append((normpath(f, lib_dir), digest, str(length)))
+    for f in installed:
+        installed_rows.append((installed[f], '', ''))
+    return installed_rows
+
+
+class MissingCallableSuffix(Exception):
+    pass
+
+
+def _raise_for_invalid_entrypoint(specification):
+    # type: (str) -> None
+    entry = get_export_entry(specification)
+    if entry is not None and entry.suffix is None:
+        raise MissingCallableSuffix(str(entry))
+
+
+class PipScriptMaker(ScriptMaker):
+    def make(self, specification, options=None):
+        # type: (str, Dict[str, Any]) -> List[str]
+        _raise_for_invalid_entrypoint(specification)
+        return super(PipScriptMaker, self).make(specification, options)
+
+
+def install_unpacked_wheel(
+    name,  # type: str
+    wheeldir,  # type: str
+    wheel_zip,  # type: ZipFile
+    scheme,  # type: Scheme
+    req_description,  # type: str
+    pycompile=True,  # type: bool
+    warn_script_location=True  # type: bool
+):
+    # type: (...) -> None
+    """Install a wheel.
+
+    :param name: Name of the project to install
+    :param wheeldir: Base directory of the unpacked wheel
+    :param wheel_zip: open ZipFile for wheel being installed
+    :param scheme: Distutils scheme dictating the install directories
+    :param req_description: String used in place of the requirement, for
+        logging
+    :param pycompile: Whether to byte-compile installed Python files
+    :param warn_script_location: Whether to check that scripts are installed
+        into a directory on PATH
+    :raises UnsupportedWheel:
+        * when the directory holds an unpacked wheel with incompatible
+          Wheel-Version
+        * when the .dist-info dir does not match the wheel
+    """
+    # TODO: Investigate and break this up.
+    # TODO: Look into moving this into a dedicated class for representing an
+    #       installation.
+
+    source = wheeldir.rstrip(os.path.sep) + os.path.sep
+
+    info_dir, metadata = parse_wheel(wheel_zip, name)
+
+    if wheel_root_is_purelib(metadata):
+        lib_dir = scheme.purelib
+    else:
+        lib_dir = scheme.platlib
+
+    subdirs = os.listdir(source)
+    data_dirs = [s for s in subdirs if s.endswith('.data')]
+
+    # Record details of the files moved
+    #   installed = files copied from the wheel to the destination
+    #   changed = files changed while installing (scripts #! line typically)
+    #   generated = files newly generated during the install (script wrappers)
+    installed = {}  # type: Dict[str, str]
+    changed = set()
+    generated = []  # type: List[str]
+
+    # Compile all of the pyc files that we're going to be installing
+    if pycompile:
+        with captured_stdout() as stdout:
+            with warnings.catch_warnings():
+                warnings.filterwarnings('ignore')
+                compileall.compile_dir(source, force=True, quiet=True)
+        logger.debug(stdout.getvalue())
+
+    def record_installed(srcfile, destfile, modified=False):
+        # type: (str, str, bool) -> None
+        """Map archive RECORD paths to installation RECORD paths."""
+        oldpath = normpath(srcfile, wheeldir)
+        newpath = normpath(destfile, lib_dir)
+        installed[oldpath] = newpath
+        if modified:
+            changed.add(destfile)
+
+    def clobber(
+            source,  # type: str
+            dest,  # type: str
+            is_base,  # type: bool
+            fixer=None,  # type: Optional[Callable[[str], Any]]
+            filter=None  # type: Optional[Callable[[str], bool]]
+    ):
+        # type: (...) -> None
+        ensure_dir(dest)  # common for the 'include' path
+
+        for dir, subdirs, files in os.walk(source):
+            basedir = dir[len(source):].lstrip(os.path.sep)
+            destdir = os.path.join(dest, basedir)
+            if is_base and basedir == '':
+                subdirs[:] = [s for s in subdirs if not s.endswith('.data')]
+            for f in files:
+                # Skip unwanted files
+                if filter and filter(f):
+                    continue
+                srcfile = os.path.join(dir, f)
+                destfile = os.path.join(dest, basedir, f)
+                # directory creation is lazy and after the file filtering above
+                # to ensure we don't install empty dirs; empty dirs can't be
+                # uninstalled.
+                ensure_dir(destdir)
+
+                # copyfile (called below) truncates the destination if it
+                # exists and then writes the new contents. This is fine in most
+                # cases, but can cause a segfault if pip has loaded a shared
+                # object (e.g. from pyopenssl through its vendored urllib3)
+                # Since the shared object is mmap'd an attempt to call a
+                # symbol in it will then cause a segfault. Unlinking the file
+                # allows writing of new contents while allowing the process to
+                # continue to use the old copy.
+                if os.path.exists(destfile):
+                    os.unlink(destfile)
+
+                # We use copyfile (not move, copy, or copy2) to be extra sure
+                # that we are not moving directories over (copyfile fails for
+                # directories) as well as to ensure that we are not copying
+                # over any metadata because we want more control over what
+                # metadata we actually copy over.
+                shutil.copyfile(srcfile, destfile)
+
+                # Copy over the metadata for the file, currently this only
+                # includes the atime and mtime.
+                st = os.stat(srcfile)
+                if hasattr(os, "utime"):
+                    os.utime(destfile, (st.st_atime, st.st_mtime))
+
+                # If our file is executable, then make our destination file
+                # executable.
+                if os.access(srcfile, os.X_OK):
+                    st = os.stat(srcfile)
+                    permissions = (
+                        st.st_mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
+                    )
+                    os.chmod(destfile, permissions)
+
+                changed = False
+                if fixer:
+                    changed = fixer(destfile)
+                record_installed(srcfile, destfile, changed)
+
+    clobber(source, lib_dir, True)
+
+    dest_info_dir = os.path.join(lib_dir, info_dir)
+
+    # Get the defined entry points
+    ep_file = os.path.join(dest_info_dir, 'entry_points.txt')
+    console, gui = get_entrypoints(ep_file)
+
+    def is_entrypoint_wrapper(name):
+        # type: (str) -> bool
+        # EP, EP.exe and EP-script.py are scripts generated for
+        # entry point EP by setuptools
+        if name.lower().endswith('.exe'):
+            matchname = name[:-4]
+        elif name.lower().endswith('-script.py'):
+            matchname = name[:-10]
+        elif name.lower().endswith(".pya"):
+            matchname = name[:-4]
+        else:
+            matchname = name
+        # Ignore setuptools-generated scripts
+        return (matchname in console or matchname in gui)
+
+    for datadir in data_dirs:
+        fixer = None
+        filter = None
+        for subdir in os.listdir(os.path.join(wheeldir, datadir)):
+            fixer = None
+            if subdir == 'scripts':
+                fixer = fix_script
+                filter = is_entrypoint_wrapper
+            source = os.path.join(wheeldir, datadir, subdir)
+            dest = getattr(scheme, subdir)
+            clobber(source, dest, False, fixer=fixer, filter=filter)
+
+    maker = PipScriptMaker(None, scheme.scripts)
+
+    # Ensure old scripts are overwritten.
+    # See https://github.com/pypa/pip/issues/1800
+    maker.clobber = True
+
+    # Ensure we don't generate any variants for scripts because this is almost
+    # never what somebody wants.
+    # See https://bitbucket.org/pypa/distlib/issue/35/
+    maker.variants = {''}
+
+    # This is required because otherwise distlib creates scripts that are not
+    # executable.
+    # See https://bitbucket.org/pypa/distlib/issue/32/
+    maker.set_mode = True
+
+    scripts_to_generate = []
+
+    # Special case pip and setuptools to generate versioned wrappers
+    #
+    # The issue is that some projects (specifically, pip and setuptools) use
+    # code in setup.py to create "versioned" entry points - pip2.7 on Python
+    # 2.7, pip3.3 on Python 3.3, etc. But these entry points are baked into
+    # the wheel metadata at build time, and so if the wheel is installed with
+    # a *different* version of Python the entry points will be wrong. The
+    # correct fix for this is to enhance the metadata to be able to describe
+    # such versioned entry points, but that won't happen till Metadata 2.0 is
+    # available.
+    # In the meantime, projects using versioned entry points will either have
+    # incorrect versioned entry points, or they will not be able to distribute
+    # "universal" wheels (i.e., they will need a wheel per Python version).
+    #
+    # Because setuptools and pip are bundled with _ensurepip and virtualenv,
+    # we need to use universal wheels. So, as a stopgap until Metadata 2.0, we
+    # override the versioned entry points in the wheel and generate the
+    # correct ones. This code is purely a short-term measure until Metadata 2.0
+    # is available.
+    #
+    # To add the level of hack in this section of code, in order to support
+    # ensurepip this code will look for an ``ENSUREPIP_OPTIONS`` environment
+    # variable which will control which version scripts get installed.
+    #
+    # ENSUREPIP_OPTIONS=altinstall
+    #   - Only pipX.Y and easy_install-X.Y will be generated and installed
+    # ENSUREPIP_OPTIONS=install
+    #   - pipX.Y, pipX, easy_install-X.Y will be generated and installed. Note
+    #     that this option is technically if ENSUREPIP_OPTIONS is set and is
+    #     not altinstall
+    # DEFAULT
+    #   - The default behavior is to install pip, pipX, pipX.Y, easy_install
+    #     and easy_install-X.Y.
+    pip_script = console.pop('pip', None)
+    if pip_script:
+        if "ENSUREPIP_OPTIONS" not in os.environ:
+            scripts_to_generate.append('pip = ' + pip_script)
+
+        if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
+            scripts_to_generate.append(
+                'pip%s = %s' % (sys.version_info[0], pip_script)
+            )
+
+        scripts_to_generate.append(
+            'pip%s = %s' % (get_major_minor_version(), pip_script)
+        )
+        # Delete any other versioned pip entry points
+        pip_ep = [k for k in console if re.match(r'pip(\d(\.\d)?)?$', k)]
+        for k in pip_ep:
+            del console[k]
+    easy_install_script = console.pop('easy_install', None)
+    if easy_install_script:
+        if "ENSUREPIP_OPTIONS" not in os.environ:
+            scripts_to_generate.append(
+                'easy_install = ' + easy_install_script
+            )
+
+        scripts_to_generate.append(
+            'easy_install-%s = %s' % (
+                get_major_minor_version(), easy_install_script
+            )
+        )
+        # Delete any other versioned easy_install entry points
+        easy_install_ep = [
+            k for k in console if re.match(r'easy_install(-\d\.\d)?$', k)
+        ]
+        for k in easy_install_ep:
+            del console[k]
+
+    # Generate the console and GUI entry points specified in the wheel
+    scripts_to_generate.extend(
+        '%s = %s' % kv for kv in console.items()
+    )
+
+    gui_scripts_to_generate = [
+        '%s = %s' % kv for kv in gui.items()
+    ]
+
+    generated_console_scripts = []  # type: List[str]
+
+    try:
+        generated_console_scripts = maker.make_multiple(scripts_to_generate)
+        generated.extend(generated_console_scripts)
+
+        generated.extend(
+            maker.make_multiple(gui_scripts_to_generate, {'gui': True})
+        )
+    except MissingCallableSuffix as e:
+        entry = e.args[0]
+        raise InstallationError(
+            "Invalid script entry point: {} for req: {} - A callable "
+            "suffix is required. Cf https://packaging.python.org/"
+            "specifications/entry-points/#use-for-scripts for more "
+            "information.".format(entry, req_description)
+        )
+
+    if warn_script_location:
+        msg = message_about_scripts_not_on_PATH(generated_console_scripts)
+        if msg is not None:
+            logger.warning(msg)
+
+    # Record pip as the installer
+    installer = os.path.join(dest_info_dir, 'INSTALLER')
+    temp_installer = os.path.join(dest_info_dir, 'INSTALLER.pip')
+    with open(temp_installer, 'wb') as installer_file:
+        installer_file.write(b'pip\n')
+    shutil.move(temp_installer, installer)
+    generated.append(installer)
+
+    # Record details of all files installed
+    record = os.path.join(dest_info_dir, 'RECORD')
+    temp_record = os.path.join(dest_info_dir, 'RECORD.pip')
+    with open_for_csv(record, 'r') as record_in:
+        with open_for_csv(temp_record, 'w+') as record_out:
+            reader = csv.reader(record_in)
+            outrows = get_csv_rows_for_installed(
+                reader, installed=installed, changed=changed,
+                generated=generated, lib_dir=lib_dir,
+            )
+            writer = csv.writer(record_out)
+            # Sort to simplify testing.
+            for row in sorted_outrows(outrows):
+                writer.writerow(row)
+    shutil.move(temp_record, record)
+
+
+def install_wheel(
+    name,  # type: str
+    wheel_path,  # type: str
+    scheme,  # type: Scheme
+    req_description,  # type: str
+    pycompile=True,  # type: bool
+    warn_script_location=True,  # type: bool
+    _temp_dir_for_testing=None,  # type: Optional[str]
+):
+    # type: (...) -> None
+    with TempDirectory(
+        path=_temp_dir_for_testing, kind="unpacked-wheel"
+    ) as unpacked_dir, ZipFile(wheel_path, allowZip64=True) as z:
+        unpack_file(wheel_path, unpacked_dir.path)
+        install_unpacked_wheel(
+            name=name,
+            wheeldir=unpacked_dir.path,
+            wheel_zip=z,
+            scheme=scheme,
+            req_description=req_description,
+            pycompile=pycompile,
+            warn_script_location=warn_script_location,
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/operations/prepare.py

@@ -0,0 +1,591 @@
+"""Prepares a distribution for installation
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import logging
+import mimetypes
+import os
+import shutil
+import sys
+
+from pip._vendor import requests
+from pip._vendor.six import PY2
+
+from pip._internal.distributions import (
+    make_distribution_for_install_requirement,
+)
+from pip._internal.distributions.installed import InstalledDistribution
+from pip._internal.exceptions import (
+    DirectoryUrlHashUnsupported,
+    HashMismatch,
+    HashUnpinned,
+    InstallationError,
+    PreviousBuildDirError,
+    VcsHashUnsupported,
+)
+from pip._internal.utils.filesystem import copy2_fixed
+from pip._internal.utils.hashes import MissingHashes
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.marker_files import write_delete_marker_file
+from pip._internal.utils.misc import (
+    ask_path_exists,
+    backup_dir,
+    display_path,
+    hide_url,
+    path_to_display,
+    rmtree,
+)
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.unpacking import unpack_file
+from pip._internal.vcs import vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Callable, List, Optional, Tuple,
+    )
+
+    from mypy_extensions import TypedDict
+
+    from pip._internal.distributions import AbstractDistribution
+    from pip._internal.index.package_finder import PackageFinder
+    from pip._internal.models.link import Link
+    from pip._internal.network.download import Downloader
+    from pip._internal.req.req_install import InstallRequirement
+    from pip._internal.req.req_tracker import RequirementTracker
+    from pip._internal.utils.hashes import Hashes
+
+    if PY2:
+        CopytreeKwargs = TypedDict(
+            'CopytreeKwargs',
+            {
+                'ignore': Callable[[str, List[str]], List[str]],
+                'symlinks': bool,
+            },
+            total=False,
+        )
+    else:
+        CopytreeKwargs = TypedDict(
+            'CopytreeKwargs',
+            {
+                'copy_function': Callable[[str, str], None],
+                'ignore': Callable[[str, List[str]], List[str]],
+                'ignore_dangling_symlinks': bool,
+                'symlinks': bool,
+            },
+            total=False,
+        )
+
+logger = logging.getLogger(__name__)
+
+
+def _get_prepared_distribution(
+        req,  # type: InstallRequirement
+        req_tracker,  # type: RequirementTracker
+        finder,  # type: PackageFinder
+        build_isolation  # type: bool
+):
+    # type: (...) -> AbstractDistribution
+    """Prepare a distribution for installation.
+    """
+    abstract_dist = make_distribution_for_install_requirement(req)
+    with req_tracker.track(req):
+        abstract_dist.prepare_distribution_metadata(finder, build_isolation)
+    return abstract_dist
+
+
+def unpack_vcs_link(link, location):
+    # type: (Link, str) -> None
+    vcs_backend = vcs.get_backend_for_scheme(link.scheme)
+    assert vcs_backend is not None
+    vcs_backend.unpack(location, url=hide_url(link.url))
+
+
+def _copy_file(filename, location, link):
+    # type: (str, str, Link) -> None
+    copy = True
+    download_location = os.path.join(location, link.filename)
+    if os.path.exists(download_location):
+        response = ask_path_exists(
+            'The file {} exists. (i)gnore, (w)ipe, (b)ackup, (a)abort'.format(
+                display_path(download_location)
+            ),
+            ('i', 'w', 'b', 'a'),
+        )
+        if response == 'i':
+            copy = False
+        elif response == 'w':
+            logger.warning('Deleting %s', display_path(download_location))
+            os.remove(download_location)
+        elif response == 'b':
+            dest_file = backup_dir(download_location)
+            logger.warning(
+                'Backing up %s to %s',
+                display_path(download_location),
+                display_path(dest_file),
+            )
+            shutil.move(download_location, dest_file)
+        elif response == 'a':
+            sys.exit(-1)
+    if copy:
+        shutil.copy(filename, download_location)
+        logger.info('Saved %s', display_path(download_location))
+
+
+def unpack_http_url(
+    link,  # type: Link
+    location,  # type: str
+    downloader,  # type: Downloader
+    download_dir=None,  # type: Optional[str]
+    hashes=None,  # type: Optional[Hashes]
+):
+    # type: (...) -> str
+    temp_dir = TempDirectory(kind="unpack", globally_managed=True)
+    # If a download dir is specified, is the file already downloaded there?
+    already_downloaded_path = None
+    if download_dir:
+        already_downloaded_path = _check_download_dir(
+            link, download_dir, hashes
+        )
+
+    if already_downloaded_path:
+        from_path = already_downloaded_path
+        content_type = mimetypes.guess_type(from_path)[0]
+    else:
+        # let's download to a tmp dir
+        from_path, content_type = _download_http_url(
+            link, downloader, temp_dir.path, hashes
+        )
+
+    # unpack the archive to the build dir location. even when only
+    # downloading archives, they have to be unpacked to parse dependencies
+    unpack_file(from_path, location, content_type)
+
+    return from_path
+
+
+def _copy2_ignoring_special_files(src, dest):
+    # type: (str, str) -> None
+    """Copying special files is not supported, but as a convenience to users
+    we skip errors copying them. This supports tools that may create e.g.
+    socket files in the project source directory.
+    """
+    try:
+        copy2_fixed(src, dest)
+    except shutil.SpecialFileError as e:
+        # SpecialFileError may be raised due to either the source or
+        # destination. If the destination was the cause then we would actually
+        # care, but since the destination directory is deleted prior to
+        # copy we ignore all of them assuming it is caused by the source.
+        logger.warning(
+            "Ignoring special file error '%s' encountered copying %s to %s.",
+            str(e),
+            path_to_display(src),
+            path_to_display(dest),
+        )
+
+
+def _copy_source_tree(source, target):
+    # type: (str, str) -> None
+    def ignore(d, names):
+        # type: (str, List[str]) -> List[str]
+        # Pulling in those directories can potentially be very slow,
+        # exclude the following directories if they appear in the top
+        # level dir (and only it).
+        # See discussion at https://github.com/pypa/pip/pull/6770
+        return ['.tox', '.nox'] if d == source else []
+
+    kwargs = dict(ignore=ignore, symlinks=True)  # type: CopytreeKwargs
+
+    if not PY2:
+        # Python 2 does not support copy_function, so we only ignore
+        # errors on special file copy in Python 3.
+        kwargs['copy_function'] = _copy2_ignoring_special_files
+
+    shutil.copytree(source, target, **kwargs)
+
+
+def unpack_file_url(
+    link,  # type: Link
+    location,  # type: str
+    download_dir=None,  # type: Optional[str]
+    hashes=None  # type: Optional[Hashes]
+):
+    # type: (...) -> Optional[str]
+    """Unpack link into location.
+    """
+    link_path = link.file_path
+    # If it's a url to a local directory
+    if link.is_existing_dir():
+        if os.path.isdir(location):
+            rmtree(location)
+        _copy_source_tree(link_path, location)
+        return None
+
+    # If a download dir is specified, is the file already there and valid?
+    already_downloaded_path = None
+    if download_dir:
+        already_downloaded_path = _check_download_dir(
+            link, download_dir, hashes
+        )
+
+    if already_downloaded_path:
+        from_path = already_downloaded_path
+    else:
+        from_path = link_path
+
+    # If --require-hashes is off, `hashes` is either empty, the
+    # link's embedded hash, or MissingHashes; it is required to
+    # match. If --require-hashes is on, we are satisfied by any
+    # hash in `hashes` matching: a URL-based or an option-based
+    # one; no internet-sourced hash will be in `hashes`.
+    if hashes:
+        hashes.check_against_path(from_path)
+
+    content_type = mimetypes.guess_type(from_path)[0]
+
+    # unpack the archive to the build dir location. even when only downloading
+    # archives, they have to be unpacked to parse dependencies
+    unpack_file(from_path, location, content_type)
+
+    return from_path
+
+
+def unpack_url(
+    link,  # type: Link
+    location,  # type: str
+    downloader,  # type: Downloader
+    download_dir=None,  # type: Optional[str]
+    hashes=None,  # type: Optional[Hashes]
+):
+    # type: (...) -> Optional[str]
+    """Unpack link into location, downloading if required.
+
+    :param hashes: A Hashes object, one of whose embedded hashes must match,
+        or HashMismatch will be raised. If the Hashes is empty, no matches are
+        required, and unhashable types of requirements (like VCS ones, which
+        would ordinarily raise HashUnsupported) are allowed.
+    """
+    # non-editable vcs urls
+    if link.is_vcs:
+        unpack_vcs_link(link, location)
+        return None
+
+    # file urls
+    elif link.is_file:
+        return unpack_file_url(link, location, download_dir, hashes=hashes)
+
+    # http urls
+    else:
+        return unpack_http_url(
+            link,
+            location,
+            downloader,
+            download_dir,
+            hashes=hashes,
+        )
+
+
+def _download_http_url(
+    link,  # type: Link
+    downloader,  # type: Downloader
+    temp_dir,  # type: str
+    hashes,  # type: Optional[Hashes]
+):
+    # type: (...) -> Tuple[str, str]
+    """Download link url into temp_dir using provided session"""
+    download = downloader(link)
+
+    file_path = os.path.join(temp_dir, download.filename)
+    with open(file_path, 'wb') as content_file:
+        for chunk in download.chunks:
+            content_file.write(chunk)
+
+    if hashes:
+        hashes.check_against_path(file_path)
+
+    return file_path, download.response.headers.get('content-type', '')
+
+
+def _check_download_dir(link, download_dir, hashes):
+    # type: (Link, str, Optional[Hashes]) -> Optional[str]
+    """ Check download_dir for previously downloaded file with correct hash
+        If a correct file is found return its path else None
+    """
+    download_path = os.path.join(download_dir, link.filename)
+
+    if not os.path.exists(download_path):
+        return None
+
+    # If already downloaded, does its hash match?
+    logger.info('File was already downloaded %s', download_path)
+    if hashes:
+        try:
+            hashes.check_against_path(download_path)
+        except HashMismatch:
+            logger.warning(
+                'Previously-downloaded file %s has bad hash. '
+                'Re-downloading.',
+                download_path
+            )
+            os.unlink(download_path)
+            return None
+    return download_path
+
+
+class RequirementPreparer(object):
+    """Prepares a Requirement
+    """
+
+    def __init__(
+        self,
+        build_dir,  # type: str
+        download_dir,  # type: Optional[str]
+        src_dir,  # type: str
+        wheel_download_dir,  # type: Optional[str]
+        build_isolation,  # type: bool
+        req_tracker,  # type: RequirementTracker
+        downloader,  # type: Downloader
+        finder,  # type: PackageFinder
+        require_hashes,  # type: bool
+        use_user_site,  # type: bool
+    ):
+        # type: (...) -> None
+        super(RequirementPreparer, self).__init__()
+
+        self.src_dir = src_dir
+        self.build_dir = build_dir
+        self.req_tracker = req_tracker
+        self.downloader = downloader
+        self.finder = finder
+
+        # Where still-packed archives should be written to. If None, they are
+        # not saved, and are deleted immediately after unpacking.
+        self.download_dir = download_dir
+
+        # Where still-packed .whl files should be written to. If None, they are
+        # written to the download_dir parameter. Separate to download_dir to
+        # permit only keeping wheel archives for pip wheel.
+        self.wheel_download_dir = wheel_download_dir
+
+        # NOTE
+        # download_dir and wheel_download_dir overlap semantically and may
+        # be combined if we're willing to have non-wheel archives present in
+        # the wheelhouse output by 'pip wheel'.
+
+        # Is build isolation allowed?
+        self.build_isolation = build_isolation
+
+        # Should hash-checking be required?
+        self.require_hashes = require_hashes
+
+        # Should install in user site-packages?
+        self.use_user_site = use_user_site
+
+    @property
+    def _download_should_save(self):
+        # type: () -> bool
+        if not self.download_dir:
+            return False
+
+        if os.path.exists(self.download_dir):
+            return True
+
+        logger.critical('Could not find download directory')
+        raise InstallationError(
+            "Could not find or access download directory '{}'"
+            .format(self.download_dir))
+
+    def prepare_linked_requirement(
+        self,
+        req,  # type: InstallRequirement
+    ):
+        # type: (...) -> AbstractDistribution
+        """Prepare a requirement that would be obtained from req.link
+        """
+        assert req.link
+        link = req.link
+
+        # TODO: Breakup into smaller functions
+        if link.scheme == 'file':
+            path = link.file_path
+            logger.info('Processing %s', display_path(path))
+        else:
+            logger.info('Collecting %s', req.req or req)
+
+        with indent_log():
+            # @@ if filesystem packages are not marked
+            # editable in a req, a non deterministic error
+            # occurs when the script attempts to unpack the
+            # build directory
+            # Since source_dir is only set for editable requirements.
+            assert req.source_dir is None
+            req.ensure_has_source_dir(self.build_dir)
+            # If a checkout exists, it's unwise to keep going.  version
+            # inconsistencies are logged later, but do not fail the
+            # installation.
+            # FIXME: this won't upgrade when there's an existing
+            # package unpacked in `req.source_dir`
+            if os.path.exists(os.path.join(req.source_dir, 'setup.py')):
+                raise PreviousBuildDirError(
+                    "pip can't proceed with requirements '{}' due to a"
+                    " pre-existing build directory ({}). This is "
+                    "likely due to a previous installation that failed"
+                    ". pip is being responsible and not assuming it "
+                    "can delete this. Please delete it and try again."
+                    .format(req, req.source_dir)
+                )
+
+            # Now that we have the real link, we can tell what kind of
+            # requirements we have and raise some more informative errors
+            # than otherwise. (For example, we can raise VcsHashUnsupported
+            # for a VCS URL rather than HashMissing.)
+            if self.require_hashes:
+                # We could check these first 2 conditions inside
+                # unpack_url and save repetition of conditions, but then
+                # we would report less-useful error messages for
+                # unhashable requirements, complaining that there's no
+                # hash provided.
+                if link.is_vcs:
+                    raise VcsHashUnsupported()
+                elif link.is_existing_dir():
+                    raise DirectoryUrlHashUnsupported()
+                if not req.original_link and not req.is_pinned:
+                    # Unpinned packages are asking for trouble when a new
+                    # version is uploaded. This isn't a security check, but
+                    # it saves users a surprising hash mismatch in the
+                    # future.
+                    #
+                    # file:/// URLs aren't pinnable, so don't complain
+                    # about them not being pinned.
+                    raise HashUnpinned()
+
+            hashes = req.hashes(trust_internet=not self.require_hashes)
+            if self.require_hashes and not hashes:
+                # Known-good hashes are missing for this requirement, so
+                # shim it with a facade object that will provoke hash
+                # computation and then raise a HashMissing exception
+                # showing the user what the hash should be.
+                hashes = MissingHashes()
+
+            download_dir = self.download_dir
+            if link.is_wheel and self.wheel_download_dir:
+                # when doing 'pip wheel` we download wheels to a
+                # dedicated dir.
+                download_dir = self.wheel_download_dir
+
+            try:
+                local_path = unpack_url(
+                    link, req.source_dir, self.downloader, download_dir,
+                    hashes=hashes,
+                )
+            except requests.HTTPError as exc:
+                logger.critical(
+                    'Could not install requirement %s because of error %s',
+                    req,
+                    exc,
+                )
+                raise InstallationError(
+                    'Could not install requirement {} because of HTTP '
+                    'error {} for URL {}'.format(req, exc, link)
+                )
+
+            # For use in later processing, preserve the file path on the
+            # requirement.
+            if local_path:
+                req.local_file_path = local_path
+
+            if link.is_wheel:
+                if download_dir:
+                    # When downloading, we only unpack wheels to get
+                    # metadata.
+                    autodelete_unpacked = True
+                else:
+                    # When installing a wheel, we use the unpacked
+                    # wheel.
+                    autodelete_unpacked = False
+            else:
+                # We always delete unpacked sdists after pip runs.
+                autodelete_unpacked = True
+            if autodelete_unpacked:
+                write_delete_marker_file(req.source_dir)
+
+            abstract_dist = _get_prepared_distribution(
+                req, self.req_tracker, self.finder, self.build_isolation,
+            )
+
+            if download_dir:
+                if link.is_existing_dir():
+                    logger.info('Link is a directory, ignoring download_dir')
+                elif local_path and not os.path.exists(
+                    os.path.join(download_dir, link.filename)
+                ):
+                    _copy_file(local_path, download_dir, link)
+
+            if self._download_should_save:
+                # Make a .zip of the source_dir we already created.
+                if link.is_vcs:
+                    req.archive(self.download_dir)
+        return abstract_dist
+
+    def prepare_editable_requirement(
+        self,
+        req,  # type: InstallRequirement
+    ):
+        # type: (...) -> AbstractDistribution
+        """Prepare an editable requirement
+        """
+        assert req.editable, "cannot prepare a non-editable req as editable"
+
+        logger.info('Obtaining %s', req)
+
+        with indent_log():
+            if self.require_hashes:
+                raise InstallationError(
+                    'The editable requirement {} cannot be installed when '
+                    'requiring hashes, because there is no single file to '
+                    'hash.'.format(req)
+                )
+            req.ensure_has_source_dir(self.src_dir)
+            req.update_editable(not self._download_should_save)
+
+            abstract_dist = _get_prepared_distribution(
+                req, self.req_tracker, self.finder, self.build_isolation,
+            )
+
+            if self._download_should_save:
+                req.archive(self.download_dir)
+            req.check_if_exists(self.use_user_site)
+
+        return abstract_dist
+
+    def prepare_installed_requirement(
+        self,
+        req,  # type: InstallRequirement
+        skip_reason  # type: str
+    ):
+        # type: (...) -> AbstractDistribution
+        """Prepare an already-installed requirement
+        """
+        assert req.satisfied_by, "req should have been satisfied but isn't"
+        assert skip_reason is not None, (
+            "did not get skip reason skipped but req.satisfied_by "
+            "is set to {}".format(req.satisfied_by)
+        )
+        logger.info(
+            'Requirement %s: %s (%s)',
+            skip_reason, req, req.satisfied_by.version
+        )
+        with indent_log():
+            if self.require_hashes:
+                logger.debug(
+                    'Since it is already installed, we are trusting this '
+                    'package without checking its hash. To ensure a '
+                    'completely repeatable environment, install into an '
+                    'empty virtualenv.'
+                )
+            abstract_dist = InstalledDistribution(req)
+
+        return abstract_dist

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/pep425tags.py

@@ -0,0 +1,167 @@
+"""Generate and work with PEP 425 Compatibility Tags."""
+from __future__ import absolute_import
+
+import logging
+import re
+
+from pip._vendor.packaging.tags import (
+    Tag,
+    compatible_tags,
+    cpython_tags,
+    generic_tags,
+    interpreter_name,
+    interpreter_version,
+    mac_platforms,
+)
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import List, Optional, Tuple
+
+    from pip._vendor.packaging.tags import PythonVersion
+
+logger = logging.getLogger(__name__)
+
+_osx_arch_pat = re.compile(r'(.+)_(\d+)_(\d+)_(.+)')
+
+
+def version_info_to_nodot(version_info):
+    # type: (Tuple[int, ...]) -> str
+    # Only use up to the first two numbers.
+    return ''.join(map(str, version_info[:2]))
+
+
+def _mac_platforms(arch):
+    # type: (str) -> List[str]
+    match = _osx_arch_pat.match(arch)
+    if match:
+        name, major, minor, actual_arch = match.groups()
+        mac_version = (int(major), int(minor))
+        arches = [
+            # Since we have always only checked that the platform starts
+            # with "macosx", for backwards-compatibility we extract the
+            # actual prefix provided by the user in case they provided
+            # something like "macosxcustom_". It may be good to remove
+            # this as undocumented or deprecate it in the future.
+            '{}_{}'.format(name, arch[len('macosx_'):])
+            for arch in mac_platforms(mac_version, actual_arch)
+        ]
+    else:
+        # arch pattern didn't match (?!)
+        arches = [arch]
+    return arches
+
+
+def _custom_manylinux_platforms(arch):
+    # type: (str) -> List[str]
+    arches = [arch]
+    arch_prefix, arch_sep, arch_suffix = arch.partition('_')
+    if arch_prefix == 'manylinux2014':
+        # manylinux1/manylinux2010 wheels run on most manylinux2014 systems
+        # with the exception of wheels depending on ncurses. PEP 599 states
+        # manylinux1/manylinux2010 wheels should be considered
+        # manylinux2014 wheels:
+        # https://www.python.org/dev/peps/pep-0599/#backwards-compatibility-with-manylinux2010-wheels
+        if arch_suffix in {'i686', 'x86_64'}:
+            arches.append('manylinux2010' + arch_sep + arch_suffix)
+            arches.append('manylinux1' + arch_sep + arch_suffix)
+    elif arch_prefix == 'manylinux2010':
+        # manylinux1 wheels run on most manylinux2010 systems with the
+        # exception of wheels depending on ncurses. PEP 571 states
+        # manylinux1 wheels should be considered manylinux2010 wheels:
+        # https://www.python.org/dev/peps/pep-0571/#backwards-compatibility-with-manylinux1-wheels
+        arches.append('manylinux1' + arch_sep + arch_suffix)
+    return arches
+
+
+def _get_custom_platforms(arch):
+    # type: (str) -> List[str]
+    arch_prefix, arch_sep, arch_suffix = arch.partition('_')
+    if arch.startswith('macosx'):
+        arches = _mac_platforms(arch)
+    elif arch_prefix in ['manylinux2014', 'manylinux2010']:
+        arches = _custom_manylinux_platforms(arch)
+    else:
+        arches = [arch]
+    return arches
+
+
+def _get_python_version(version):
+    # type: (str) -> PythonVersion
+    if len(version) > 1:
+        return int(version[0]), int(version[1:])
+    else:
+        return (int(version[0]),)
+
+
+def _get_custom_interpreter(implementation=None, version=None):
+    # type: (Optional[str], Optional[str]) -> str
+    if implementation is None:
+        implementation = interpreter_name()
+    if version is None:
+        version = interpreter_version()
+    return "{}{}".format(implementation, version)
+
+
+def get_supported(
+    version=None,  # type: Optional[str]
+    platform=None,  # type: Optional[str]
+    impl=None,  # type: Optional[str]
+    abi=None  # type: Optional[str]
+):
+    # type: (...) -> List[Tag]
+    """Return a list of supported tags for each version specified in
+    `versions`.
+
+    :param version: a string version, of the form "33" or "32",
+        or None. The version will be assumed to support our ABI.
+    :param platform: specify the exact platform you want valid
+        tags for, or None. If None, use the local system platform.
+    :param impl: specify the exact implementation you want valid
+        tags for, or None. If None, use the local interpreter impl.
+    :param abi: specify the exact abi you want valid
+        tags for, or None. If None, use the local interpreter abi.
+    """
+    supported = []  # type: List[Tag]
+
+    python_version = None  # type: Optional[PythonVersion]
+    if version is not None:
+        python_version = _get_python_version(version)
+
+    interpreter = _get_custom_interpreter(impl, version)
+
+    abis = None  # type: Optional[List[str]]
+    if abi is not None:
+        abis = [abi]
+
+    platforms = None  # type: Optional[List[str]]
+    if platform is not None:
+        platforms = _get_custom_platforms(platform)
+
+    is_cpython = (impl or interpreter_name()) == "cp"
+    if is_cpython:
+        supported.extend(
+            cpython_tags(
+                python_version=python_version,
+                abis=abis,
+                platforms=platforms,
+            )
+        )
+    else:
+        supported.extend(
+            generic_tags(
+                interpreter=interpreter,
+                abis=abis,
+                platforms=platforms,
+            )
+        )
+    supported.extend(
+        compatible_tags(
+            python_version=python_version,
+            interpreter=interpreter,
+            platforms=platforms,
+        )
+    )
+
+    return supported

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/pyproject.py

@@ -0,0 +1,196 @@
+from __future__ import absolute_import
+
+import io
+import os
+import sys
+from collections import namedtuple
+
+from pip._vendor import six, toml
+from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
+
+from pip._internal.exceptions import InstallationError
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, Optional, List
+
+
+def _is_list_of_str(obj):
+    # type: (Any) -> bool
+    return (
+        isinstance(obj, list) and
+        all(isinstance(item, six.string_types) for item in obj)
+    )
+
+
+def make_pyproject_path(unpacked_source_directory):
+    # type: (str) -> str
+    path = os.path.join(unpacked_source_directory, 'pyproject.toml')
+
+    # Python2 __file__ should not be unicode
+    if six.PY2 and isinstance(path, six.text_type):
+        path = path.encode(sys.getfilesystemencoding())
+
+    return path
+
+
+BuildSystemDetails = namedtuple('BuildSystemDetails', [
+    'requires', 'backend', 'check', 'backend_path'
+])
+
+
+def load_pyproject_toml(
+    use_pep517,  # type: Optional[bool]
+    pyproject_toml,  # type: str
+    setup_py,  # type: str
+    req_name  # type: str
+):
+    # type: (...) -> Optional[BuildSystemDetails]
+    """Load the pyproject.toml file.
+
+    Parameters:
+        use_pep517 - Has the user requested PEP 517 processing? None
+                     means the user hasn't explicitly specified.
+        pyproject_toml - Location of the project's pyproject.toml file
+        setup_py - Location of the project's setup.py file
+        req_name - The name of the requirement we're processing (for
+                   error reporting)
+
+    Returns:
+        None if we should use the legacy code path, otherwise a tuple
+        (
+            requirements from pyproject.toml,
+            name of PEP 517 backend,
+            requirements we should check are installed after setting
+                up the build environment
+            directory paths to import the backend from (backend-path),
+                relative to the project root.
+        )
+    """
+    has_pyproject = os.path.isfile(pyproject_toml)
+    has_setup = os.path.isfile(setup_py)
+
+    if has_pyproject:
+        with io.open(pyproject_toml, encoding="utf-8") as f:
+            pp_toml = toml.load(f)
+        build_system = pp_toml.get("build-system")
+    else:
+        build_system = None
+
+    # The following cases must use PEP 517
+    # We check for use_pep517 being non-None and falsey because that means
+    # the user explicitly requested --no-use-pep517.  The value 0 as
+    # opposed to False can occur when the value is provided via an
+    # environment variable or config file option (due to the quirk of
+    # strtobool() returning an integer in pip's configuration code).
+    if has_pyproject and not has_setup:
+        if use_pep517 is not None and not use_pep517:
+            raise InstallationError(
+                "Disabling PEP 517 processing is invalid: "
+                "project does not have a setup.py"
+            )
+        use_pep517 = True
+    elif build_system and "build-backend" in build_system:
+        if use_pep517 is not None and not use_pep517:
+            raise InstallationError(
+                "Disabling PEP 517 processing is invalid: "
+                "project specifies a build backend of {} "
+                "in pyproject.toml".format(
+                    build_system["build-backend"]
+                )
+            )
+        use_pep517 = True
+
+    # If we haven't worked out whether to use PEP 517 yet,
+    # and the user hasn't explicitly stated a preference,
+    # we do so if the project has a pyproject.toml file.
+    elif use_pep517 is None:
+        use_pep517 = has_pyproject
+
+    # At this point, we know whether we're going to use PEP 517.
+    assert use_pep517 is not None
+
+    # If we're using the legacy code path, there is nothing further
+    # for us to do here.
+    if not use_pep517:
+        return None
+
+    if build_system is None:
+        # Either the user has a pyproject.toml with no build-system
+        # section, or the user has no pyproject.toml, but has opted in
+        # explicitly via --use-pep517.
+        # In the absence of any explicit backend specification, we
+        # assume the setuptools backend that most closely emulates the
+        # traditional direct setup.py execution, and require wheel and
+        # a version of setuptools that supports that backend.
+
+        build_system = {
+            "requires": ["setuptools>=40.8.0", "wheel"],
+            "build-backend": "setuptools.build_meta:__legacy__",
+        }
+
+    # If we're using PEP 517, we have build system information (either
+    # from pyproject.toml, or defaulted by the code above).
+    # Note that at this point, we do not know if the user has actually
+    # specified a backend, though.
+    assert build_system is not None
+
+    # Ensure that the build-system section in pyproject.toml conforms
+    # to PEP 518.
+    error_template = (
+        "{package} has a pyproject.toml file that does not comply "
+        "with PEP 518: {reason}"
+    )
+
+    # Specifying the build-system table but not the requires key is invalid
+    if "requires" not in build_system:
+        raise InstallationError(
+            error_template.format(package=req_name, reason=(
+                "it has a 'build-system' table but not "
+                "'build-system.requires' which is mandatory in the table"
+            ))
+        )
+
+    # Error out if requires is not a list of strings
+    requires = build_system["requires"]
+    if not _is_list_of_str(requires):
+        raise InstallationError(error_template.format(
+            package=req_name,
+            reason="'build-system.requires' is not a list of strings.",
+        ))
+
+    # Each requirement must be valid as per PEP 508
+    for requirement in requires:
+        try:
+            Requirement(requirement)
+        except InvalidRequirement:
+            raise InstallationError(
+                error_template.format(
+                    package=req_name,
+                    reason=(
+                        "'build-system.requires' contains an invalid "
+                        "requirement: {!r}".format(requirement)
+                    ),
+                )
+            )
+
+    backend = build_system.get("build-backend")
+    backend_path = build_system.get("backend-path", [])
+    check = []  # type: List[str]
+    if backend is None:
+        # If the user didn't specify a backend, we assume they want to use
+        # the setuptools backend. But we can't be sure they have included
+        # a version of setuptools which supplies the backend, or wheel
+        # (which is needed by the backend) in their requirements. So we
+        # make a note to check that those requirements are present once
+        # we have set up the environment.
+        # This is quite a lot of work to check for a very specific case. But
+        # the problem is, that case is potentially quite common - projects that
+        # adopted PEP 518 early for the ability to specify requirements to
+        # execute setup.py, but never considered needing to mention the build
+        # tools themselves. The original PEP 518 code had a similar check (but
+        # implemented in a different way).
+        backend = "setuptools.build_meta:__legacy__"
+        check = ["setuptools>=40.8.0", "wheel"]
+
+    return BuildSystemDetails(requires, backend, check, backend_path)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/req/__init__.py

@@ -0,0 +1,92 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import logging
+
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+from .req_file import parse_requirements
+from .req_install import InstallRequirement
+from .req_set import RequirementSet
+
+if MYPY_CHECK_RUNNING:
+    from typing import Any, List, Sequence
+
+__all__ = [
+    "RequirementSet", "InstallRequirement",
+    "parse_requirements", "install_given_reqs",
+]
+
+logger = logging.getLogger(__name__)
+
+
+class InstallationResult(object):
+    def __init__(self, name):
+        # type: (str) -> None
+        self.name = name
+
+    def __repr__(self):
+        # type: () -> str
+        return "InstallationResult(name={!r})".format(self.name)
+
+
+def install_given_reqs(
+    to_install,  # type: List[InstallRequirement]
+    install_options,  # type: List[str]
+    global_options=(),  # type: Sequence[str]
+    *args,  # type: Any
+    **kwargs  # type: Any
+):
+    # type: (...) -> List[InstallationResult]
+    """
+    Install everything in the given list.
+
+    (to be called after having downloaded and unpacked the packages)
+    """
+
+    if to_install:
+        logger.info(
+            'Installing collected packages: %s',
+            ', '.join([req.name for req in to_install]),
+        )
+
+    installed = []
+
+    with indent_log():
+        for requirement in to_install:
+            if requirement.should_reinstall:
+                logger.info('Attempting uninstall: %s', requirement.name)
+                with indent_log():
+                    uninstalled_pathset = requirement.uninstall(
+                        auto_confirm=True
+                    )
+            try:
+                requirement.install(
+                    install_options,
+                    global_options,
+                    *args,
+                    **kwargs
+                )
+            except Exception:
+                should_rollback = (
+                    requirement.should_reinstall and
+                    not requirement.install_succeeded
+                )
+                # if install did not succeed, rollback previous uninstall
+                if should_rollback:
+                    uninstalled_pathset.rollback()
+                raise
+            else:
+                should_commit = (
+                    requirement.should_reinstall and
+                    requirement.install_succeeded
+                )
+                if should_commit:
+                    uninstalled_pathset.commit()
+
+            installed.append(InstallationResult(requirement.name))
+
+    return installed

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/req/constructors.py

@@ -0,0 +1,436 @@
+"""Backing implementation for InstallRequirement's various constructors
+
+The idea here is that these formed a major chunk of InstallRequirement's size
+so, moving them and support code dedicated to them outside of that class
+helps creates for better understandability for the rest of the code.
+
+These are meant to be used elsewhere within pip to create instances of
+InstallRequirement.
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+import logging
+import os
+import re
+
+from pip._vendor.packaging.markers import Marker
+from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
+from pip._vendor.packaging.specifiers import Specifier
+from pip._vendor.pkg_resources import RequirementParseError, parse_requirements
+
+from pip._internal.exceptions import InstallationError
+from pip._internal.models.index import PyPI, TestPyPI
+from pip._internal.models.link import Link
+from pip._internal.models.wheel import Wheel
+from pip._internal.pyproject import make_pyproject_path
+from pip._internal.req.req_install import InstallRequirement
+from pip._internal.utils.filetypes import ARCHIVE_EXTENSIONS
+from pip._internal.utils.misc import is_installable_dir, splitext
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import path_to_url
+from pip._internal.vcs import is_url, vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, Dict, Optional, Set, Tuple, Union,
+    )
+    from pip._internal.cache import WheelCache
+
+
+__all__ = [
+    "install_req_from_editable", "install_req_from_line",
+    "parse_editable"
+]
+
+logger = logging.getLogger(__name__)
+operators = Specifier._operators.keys()
+
+
+def is_archive_file(name):
+    # type: (str) -> bool
+    """Return True if `name` is a considered as an archive file."""
+    ext = splitext(name)[1].lower()
+    if ext in ARCHIVE_EXTENSIONS:
+        return True
+    return False
+
+
+def _strip_extras(path):
+    # type: (str) -> Tuple[str, Optional[str]]
+    m = re.match(r'^(.+)(\[[^\]]+\])$', path)
+    extras = None
+    if m:
+        path_no_extras = m.group(1)
+        extras = m.group(2)
+    else:
+        path_no_extras = path
+
+    return path_no_extras, extras
+
+
+def convert_extras(extras):
+    # type: (Optional[str]) -> Set[str]
+    if not extras:
+        return set()
+    return Requirement("placeholder" + extras.lower()).extras
+
+
+def parse_editable(editable_req):
+    # type: (str) -> Tuple[Optional[str], str, Optional[Set[str]]]
+    """Parses an editable requirement into:
+        - a requirement name
+        - an URL
+        - extras
+        - editable options
+    Accepted requirements:
+        svn+http://blahblah@rev#egg=Foobar[baz]&subdirectory=version_subdir
+        .[some_extra]
+    """
+
+    url = editable_req
+
+    # If a file path is specified with extras, strip off the extras.
+    url_no_extras, extras = _strip_extras(url)
+
+    if os.path.isdir(url_no_extras):
+        if not os.path.exists(os.path.join(url_no_extras, 'setup.py')):
+            msg = (
+                'File "setup.py" not found. Directory cannot be installed '
+                'in editable mode: {}'.format(os.path.abspath(url_no_extras))
+            )
+            pyproject_path = make_pyproject_path(url_no_extras)
+            if os.path.isfile(pyproject_path):
+                msg += (
+                    '\n(A "pyproject.toml" file was found, but editable '
+                    'mode currently requires a setup.py based build.)'
+                )
+            raise InstallationError(msg)
+
+        # Treating it as code that has already been checked out
+        url_no_extras = path_to_url(url_no_extras)
+
+    if url_no_extras.lower().startswith('file:'):
+        package_name = Link(url_no_extras).egg_fragment
+        if extras:
+            return (
+                package_name,
+                url_no_extras,
+                Requirement("placeholder" + extras.lower()).extras,
+            )
+        else:
+            return package_name, url_no_extras, None
+
+    for version_control in vcs:
+        if url.lower().startswith('%s:' % version_control):
+            url = '%s+%s' % (version_control, url)
+            break
+
+    if '+' not in url:
+        raise InstallationError(
+            '{} is not a valid editable requirement. '
+            'It should either be a path to a local project or a VCS URL '
+            '(beginning with svn+, git+, hg+, or bzr+).'.format(editable_req)
+        )
+
+    vc_type = url.split('+', 1)[0].lower()
+
+    if not vcs.get_backend(vc_type):
+        error_message = 'For --editable=%s only ' % editable_req + \
+            ', '.join([backend.name + '+URL' for backend in vcs.backends]) + \
+            ' is currently supported'
+        raise InstallationError(error_message)
+
+    package_name = Link(url).egg_fragment
+    if not package_name:
+        raise InstallationError(
+            "Could not detect requirement name for '%s', please specify one "
+            "with #egg=your_package_name" % editable_req
+        )
+    return package_name, url, None
+
+
+def deduce_helpful_msg(req):
+    # type: (str) -> str
+    """Returns helpful msg in case requirements file does not exist,
+    or cannot be parsed.
+
+    :params req: Requirements file path
+    """
+    msg = ""
+    if os.path.exists(req):
+        msg = " It does exist."
+        # Try to parse and check if it is a requirements file.
+        try:
+            with open(req, 'r') as fp:
+                # parse first line only
+                next(parse_requirements(fp.read()))
+                msg += " The argument you provided " + \
+                    "(%s) appears to be a" % (req) + \
+                    " requirements file. If that is the" + \
+                    " case, use the '-r' flag to install" + \
+                    " the packages specified within it."
+        except RequirementParseError:
+            logger.debug("Cannot parse '%s' as requirements \
+            file" % (req), exc_info=True)
+    else:
+        msg += " File '%s' does not exist." % (req)
+    return msg
+
+
+class RequirementParts(object):
+    def __init__(
+            self,
+            requirement,  # type: Optional[Requirement]
+            link,         # type: Optional[Link]
+            markers,      # type: Optional[Marker]
+            extras,       # type: Set[str]
+    ):
+        self.requirement = requirement
+        self.link = link
+        self.markers = markers
+        self.extras = extras
+
+
+def parse_req_from_editable(editable_req):
+    # type: (str) -> RequirementParts
+    name, url, extras_override = parse_editable(editable_req)
+
+    if name is not None:
+        try:
+            req = Requirement(name)
+        except InvalidRequirement:
+            raise InstallationError("Invalid requirement: '%s'" % name)
+    else:
+        req = None
+
+    link = Link(url)
+
+    return RequirementParts(req, link, None, extras_override)
+
+
+# ---- The actual constructors follow ----
+
+
+def install_req_from_editable(
+    editable_req,  # type: str
+    comes_from=None,  # type: Optional[str]
+    use_pep517=None,  # type: Optional[bool]
+    isolated=False,  # type: bool
+    options=None,  # type: Optional[Dict[str, Any]]
+    wheel_cache=None,  # type: Optional[WheelCache]
+    constraint=False  # type: bool
+):
+    # type: (...) -> InstallRequirement
+
+    parts = parse_req_from_editable(editable_req)
+
+    source_dir = parts.link.file_path if parts.link.scheme == 'file' else None
+
+    return InstallRequirement(
+        parts.requirement, comes_from, source_dir=source_dir,
+        editable=True,
+        link=parts.link,
+        constraint=constraint,
+        use_pep517=use_pep517,
+        isolated=isolated,
+        options=options if options else {},
+        wheel_cache=wheel_cache,
+        extras=parts.extras,
+    )
+
+
+def _looks_like_path(name):
+    # type: (str) -> bool
+    """Checks whether the string "looks like" a path on the filesystem.
+
+    This does not check whether the target actually exists, only judge from the
+    appearance.
+
+    Returns true if any of the following conditions is true:
+    * a path separator is found (either os.path.sep or os.path.altsep);
+    * a dot is found (which represents the current directory).
+    """
+    if os.path.sep in name:
+        return True
+    if os.path.altsep is not None and os.path.altsep in name:
+        return True
+    if name.startswith("."):
+        return True
+    return False
+
+
+def _get_url_from_path(path, name):
+    # type: (str, str) -> str
+    """
+    First, it checks whether a provided path is an installable directory
+    (e.g. it has a setup.py). If it is, returns the path.
+
+    If false, check if the path is an archive file (such as a .whl).
+    The function checks if the path is a file. If false, if the path has
+    an @, it will treat it as a PEP 440 URL requirement and return the path.
+    """
+    if _looks_like_path(name) and os.path.isdir(path):
+        if is_installable_dir(path):
+            return path_to_url(path)
+        raise InstallationError(
+            "Directory %r is not installable. Neither 'setup.py' "
+            "nor 'pyproject.toml' found." % name
+        )
+    if not is_archive_file(path):
+        return None
+    if os.path.isfile(path):
+        return path_to_url(path)
+    urlreq_parts = name.split('@', 1)
+    if len(urlreq_parts) >= 2 and not _looks_like_path(urlreq_parts[0]):
+        # If the path contains '@' and the part before it does not look
+        # like a path, try to treat it as a PEP 440 URL req instead.
+        return None
+    logger.warning(
+        'Requirement %r looks like a filename, but the '
+        'file does not exist',
+        name
+    )
+    return path_to_url(path)
+
+
+def parse_req_from_line(name, line_source):
+    # type: (str, Optional[str]) -> RequirementParts
+    if is_url(name):
+        marker_sep = '; '
+    else:
+        marker_sep = ';'
+    if marker_sep in name:
+        name, markers_as_string = name.split(marker_sep, 1)
+        markers_as_string = markers_as_string.strip()
+        if not markers_as_string:
+            markers = None
+        else:
+            markers = Marker(markers_as_string)
+    else:
+        markers = None
+    name = name.strip()
+    req_as_string = None
+    path = os.path.normpath(os.path.abspath(name))
+    link = None
+    extras_as_string = None
+
+    if is_url(name):
+        link = Link(name)
+    else:
+        p, extras_as_string = _strip_extras(path)
+        url = _get_url_from_path(p, name)
+        if url is not None:
+            link = Link(url)
+
+    # it's a local file, dir, or url
+    if link:
+        # Handle relative file URLs
+        if link.scheme == 'file' and re.search(r'\.\./', link.url):
+            link = Link(
+                path_to_url(os.path.normpath(os.path.abspath(link.path))))
+        # wheel file
+        if link.is_wheel:
+            wheel = Wheel(link.filename)  # can raise InvalidWheelFilename
+            req_as_string = "%s==%s" % (wheel.name, wheel.version)
+        else:
+            # set the req to the egg fragment.  when it's not there, this
+            # will become an 'unnamed' requirement
+            req_as_string = link.egg_fragment
+
+    # a requirement specifier
+    else:
+        req_as_string = name
+
+    extras = convert_extras(extras_as_string)
+
+    def with_source(text):
+        # type: (str) -> str
+        if not line_source:
+            return text
+        return '{} (from {})'.format(text, line_source)
+
+    if req_as_string is not None:
+        try:
+            req = Requirement(req_as_string)
+        except InvalidRequirement:
+            if os.path.sep in req_as_string:
+                add_msg = "It looks like a path."
+                add_msg += deduce_helpful_msg(req_as_string)
+            elif ('=' in req_as_string and
+                  not any(op in req_as_string for op in operators)):
+                add_msg = "= is not a valid operator. Did you mean == ?"
+            else:
+                add_msg = ''
+            msg = with_source(
+                'Invalid requirement: {!r}'.format(req_as_string)
+            )
+            if add_msg:
+                msg += '\nHint: {}'.format(add_msg)
+            raise InstallationError(msg)
+    else:
+        req = None
+
+    return RequirementParts(req, link, markers, extras)
+
+
+def install_req_from_line(
+    name,  # type: str
+    comes_from=None,  # type: Optional[Union[str, InstallRequirement]]
+    use_pep517=None,  # type: Optional[bool]
+    isolated=False,  # type: bool
+    options=None,  # type: Optional[Dict[str, Any]]
+    wheel_cache=None,  # type: Optional[WheelCache]
+    constraint=False,  # type: bool
+    line_source=None,  # type: Optional[str]
+):
+    # type: (...) -> InstallRequirement
+    """Creates an InstallRequirement from a name, which might be a
+    requirement, directory containing 'setup.py', filename, or URL.
+
+    :param line_source: An optional string describing where the line is from,
+        for logging purposes in case of an error.
+    """
+    parts = parse_req_from_line(name, line_source)
+
+    return InstallRequirement(
+        parts.requirement, comes_from, link=parts.link, markers=parts.markers,
+        use_pep517=use_pep517, isolated=isolated,
+        options=options if options else {},
+        wheel_cache=wheel_cache,
+        constraint=constraint,
+        extras=parts.extras,
+    )
+
+
+def install_req_from_req_string(
+    req_string,  # type: str
+    comes_from=None,  # type: Optional[InstallRequirement]
+    isolated=False,  # type: bool
+    wheel_cache=None,  # type: Optional[WheelCache]
+    use_pep517=None  # type: Optional[bool]
+):
+    # type: (...) -> InstallRequirement
+    try:
+        req = Requirement(req_string)
+    except InvalidRequirement:
+        raise InstallationError("Invalid requirement: '%s'" % req_string)
+
+    domains_not_allowed = [
+        PyPI.file_storage_domain,
+        TestPyPI.file_storage_domain,
+    ]
+    if (req.url and comes_from and comes_from.link and
+            comes_from.link.netloc in domains_not_allowed):
+        # Explicitly disallow pypi packages that depend on external urls
+        raise InstallationError(
+            "Packages installed from PyPI cannot depend on packages "
+            "which are not also hosted on PyPI.\n"
+            "%s depends on %s " % (comes_from.name, req)
+        )
+
+    return InstallRequirement(
+        req, comes_from, isolated=isolated, wheel_cache=wheel_cache,
+        use_pep517=use_pep517
+    )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/req/req_file.py

@@ -0,0 +1,546 @@
+"""
+Requirements file parsing
+"""
+
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import optparse
+import os
+import re
+import shlex
+import sys
+
+from pip._vendor.six.moves import filterfalse
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+
+from pip._internal.cli import cmdoptions
+from pip._internal.exceptions import (
+    InstallationError,
+    RequirementsFileParseError,
+)
+from pip._internal.models.search_scope import SearchScope
+from pip._internal.req.constructors import (
+    install_req_from_editable,
+    install_req_from_line,
+)
+from pip._internal.utils.encoding import auto_decode
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import get_url_scheme
+
+if MYPY_CHECK_RUNNING:
+    from optparse import Values
+    from typing import (
+        Any, Callable, Iterator, List, NoReturn, Optional, Text, Tuple,
+    )
+
+    from pip._internal.req import InstallRequirement
+    from pip._internal.cache import WheelCache
+    from pip._internal.index.package_finder import PackageFinder
+    from pip._internal.network.session import PipSession
+
+    ReqFileLines = Iterator[Tuple[int, Text]]
+
+    LineParser = Callable[[Text], Tuple[str, Values]]
+
+
+__all__ = ['parse_requirements']
+
+SCHEME_RE = re.compile(r'^(http|https|file):', re.I)
+COMMENT_RE = re.compile(r'(^|\s+)#.*$')
+
+# Matches environment variable-style values in '${MY_VARIABLE_1}' with the
+# variable name consisting of only uppercase letters, digits or the '_'
+# (underscore). This follows the POSIX standard defined in IEEE Std 1003.1,
+# 2013 Edition.
+ENV_VAR_RE = re.compile(r'(?P<var>\$\{(?P<name>[A-Z0-9_]+)\})')
+
+SUPPORTED_OPTIONS = [
+    cmdoptions.index_url,
+    cmdoptions.extra_index_url,
+    cmdoptions.no_index,
+    cmdoptions.constraints,
+    cmdoptions.requirements,
+    cmdoptions.editable,
+    cmdoptions.find_links,
+    cmdoptions.no_binary,
+    cmdoptions.only_binary,
+    cmdoptions.require_hashes,
+    cmdoptions.pre,
+    cmdoptions.trusted_host,
+    cmdoptions.always_unzip,  # Deprecated
+]  # type: List[Callable[..., optparse.Option]]
+
+# options to be passed to requirements
+SUPPORTED_OPTIONS_REQ = [
+    cmdoptions.install_options,
+    cmdoptions.global_options,
+    cmdoptions.hash,
+]  # type: List[Callable[..., optparse.Option]]
+
+# the 'dest' string values
+SUPPORTED_OPTIONS_REQ_DEST = [str(o().dest) for o in SUPPORTED_OPTIONS_REQ]
+
+
+class ParsedLine(object):
+    def __init__(
+        self,
+        filename,  # type: str
+        lineno,  # type: int
+        comes_from,  # type: str
+        args,  # type: str
+        opts,  # type: Values
+        constraint,  # type: bool
+    ):
+        # type: (...) -> None
+        self.filename = filename
+        self.lineno = lineno
+        self.comes_from = comes_from
+        self.args = args
+        self.opts = opts
+        self.constraint = constraint
+
+
+def parse_requirements(
+    filename,  # type: str
+    session,  # type: PipSession
+    finder=None,  # type: Optional[PackageFinder]
+    comes_from=None,  # type: Optional[str]
+    options=None,  # type: Optional[optparse.Values]
+    constraint=False,  # type: bool
+    wheel_cache=None,  # type: Optional[WheelCache]
+    use_pep517=None  # type: Optional[bool]
+):
+    # type: (...) -> Iterator[InstallRequirement]
+    """Parse a requirements file and yield InstallRequirement instances.
+
+    :param filename:    Path or url of requirements file.
+    :param session:     PipSession instance.
+    :param finder:      Instance of pip.index.PackageFinder.
+    :param comes_from:  Origin description of requirements.
+    :param options:     cli options.
+    :param constraint:  If true, parsing a constraint file rather than
+        requirements file.
+    :param wheel_cache: Instance of pip.wheel.WheelCache
+    :param use_pep517:  Value of the --use-pep517 option.
+    """
+    skip_requirements_regex = (
+        options.skip_requirements_regex if options else None
+    )
+    line_parser = get_line_parser(finder)
+    parser = RequirementsFileParser(
+        session, line_parser, comes_from, skip_requirements_regex
+    )
+
+    for parsed_line in parser.parse(filename, constraint):
+        req = handle_line(
+            parsed_line, finder, options, session, wheel_cache, use_pep517
+        )
+        if req is not None:
+            yield req
+
+
+def preprocess(content, skip_requirements_regex):
+    # type: (Text, Optional[str]) -> ReqFileLines
+    """Split, filter, and join lines, and return a line iterator
+
+    :param content: the content of the requirements file
+    :param options: cli options
+    """
+    lines_enum = enumerate(content.splitlines(), start=1)  # type: ReqFileLines
+    lines_enum = join_lines(lines_enum)
+    lines_enum = ignore_comments(lines_enum)
+    if skip_requirements_regex:
+        lines_enum = skip_regex(lines_enum, skip_requirements_regex)
+    lines_enum = expand_env_variables(lines_enum)
+    return lines_enum
+
+
+def handle_line(
+    line,  # type: ParsedLine
+    finder=None,  # type: Optional[PackageFinder]
+    options=None,  # type: Optional[optparse.Values]
+    session=None,  # type: Optional[PipSession]
+    wheel_cache=None,  # type: Optional[WheelCache]
+    use_pep517=None,  # type: Optional[bool]
+):
+    # type: (...) -> Optional[InstallRequirement]
+    """Handle a single parsed requirements line; This can result in
+    creating/yielding requirements, or updating the finder.
+
+    For lines that contain requirements, the only options that have an effect
+    are from SUPPORTED_OPTIONS_REQ, and they are scoped to the
+    requirement. Other options from SUPPORTED_OPTIONS may be present, but are
+    ignored.
+
+    For lines that do not contain requirements, the only options that have an
+    effect are from SUPPORTED_OPTIONS. Options from SUPPORTED_OPTIONS_REQ may
+    be present, but are ignored. These lines may contain multiple options
+    (although our docs imply only one is supported), and all our parsed and
+    affect the finder.
+    """
+
+    # preserve for the nested code path
+    line_comes_from = '%s %s (line %s)' % (
+        '-c' if line.constraint else '-r', line.filename, line.lineno,
+    )
+
+    # return a line requirement
+    if line.args:
+        isolated = options.isolated_mode if options else False
+        if options:
+            cmdoptions.check_install_build_global(options, line.opts)
+        # get the options that apply to requirements
+        req_options = {}
+        for dest in SUPPORTED_OPTIONS_REQ_DEST:
+            if dest in line.opts.__dict__ and line.opts.__dict__[dest]:
+                req_options[dest] = line.opts.__dict__[dest]
+        line_source = 'line {} of {}'.format(line.lineno, line.filename)
+        return install_req_from_line(
+            line.args,
+            comes_from=line_comes_from,
+            use_pep517=use_pep517,
+            isolated=isolated,
+            options=req_options,
+            wheel_cache=wheel_cache,
+            constraint=line.constraint,
+            line_source=line_source,
+        )
+
+    # return an editable requirement
+    elif line.opts.editables:
+        isolated = options.isolated_mode if options else False
+        return install_req_from_editable(
+            line.opts.editables[0], comes_from=line_comes_from,
+            use_pep517=use_pep517,
+            constraint=line.constraint, isolated=isolated,
+            wheel_cache=wheel_cache
+        )
+
+    # percolate hash-checking option upward
+    elif line.opts.require_hashes:
+        options.require_hashes = line.opts.require_hashes
+
+    # set finder options
+    elif finder:
+        find_links = finder.find_links
+        index_urls = finder.index_urls
+        if line.opts.index_url:
+            index_urls = [line.opts.index_url]
+        if line.opts.no_index is True:
+            index_urls = []
+        if line.opts.extra_index_urls:
+            index_urls.extend(line.opts.extra_index_urls)
+        if line.opts.find_links:
+            # FIXME: it would be nice to keep track of the source
+            # of the find_links: support a find-links local path
+            # relative to a requirements file.
+            value = line.opts.find_links[0]
+            req_dir = os.path.dirname(os.path.abspath(line.filename))
+            relative_to_reqs_file = os.path.join(req_dir, value)
+            if os.path.exists(relative_to_reqs_file):
+                value = relative_to_reqs_file
+            find_links.append(value)
+
+        search_scope = SearchScope(
+            find_links=find_links,
+            index_urls=index_urls,
+        )
+        finder.search_scope = search_scope
+
+        if line.opts.pre:
+            finder.set_allow_all_prereleases()
+
+        if session:
+            for host in line.opts.trusted_hosts or []:
+                source = 'line {} of {}'.format(line.lineno, line.filename)
+                session.add_trusted_host(host, source=source)
+
+    return None
+
+
+class RequirementsFileParser(object):
+    def __init__(
+        self,
+        session,  # type: PipSession
+        line_parser,  # type: LineParser
+        comes_from,  # type: str
+        skip_requirements_regex,  # type: Optional[str]
+    ):
+        # type: (...) -> None
+        self._session = session
+        self._line_parser = line_parser
+        self._comes_from = comes_from
+        self._skip_requirements_regex = skip_requirements_regex
+
+    def parse(self, filename, constraint):
+        # type: (str, bool) -> Iterator[ParsedLine]
+        """Parse a given file, yielding parsed lines.
+        """
+        for line in self._parse_and_recurse(filename, constraint):
+            yield line
+
+    def _parse_and_recurse(self, filename, constraint):
+        # type: (str, bool) -> Iterator[ParsedLine]
+        for line in self._parse_file(filename, constraint):
+            if (
+                not line.args and
+                not line.opts.editables and
+                (line.opts.requirements or line.opts.constraints)
+            ):
+                # parse a nested requirements file
+                if line.opts.requirements:
+                    req_path = line.opts.requirements[0]
+                    nested_constraint = False
+                else:
+                    req_path = line.opts.constraints[0]
+                    nested_constraint = True
+
+                # original file is over http
+                if SCHEME_RE.search(filename):
+                    # do a url join so relative paths work
+                    req_path = urllib_parse.urljoin(filename, req_path)
+                # original file and nested file are paths
+                elif not SCHEME_RE.search(req_path):
+                    # do a join so relative paths work
+                    req_path = os.path.join(
+                        os.path.dirname(filename), req_path,
+                    )
+
+                for inner_line in self._parse_and_recurse(
+                    req_path, nested_constraint,
+                ):
+                    yield inner_line
+            else:
+                yield line
+
+    def _parse_file(self, filename, constraint):
+        # type: (str, bool) -> Iterator[ParsedLine]
+        _, content = get_file_content(
+            filename, self._session, comes_from=self._comes_from
+        )
+
+        lines_enum = preprocess(content, self._skip_requirements_regex)
+
+        for line_number, line in lines_enum:
+            try:
+                args_str, opts = self._line_parser(line)
+            except OptionParsingError as e:
+                # add offending line
+                msg = 'Invalid requirement: %s\n%s' % (line, e.msg)
+                raise RequirementsFileParseError(msg)
+
+            yield ParsedLine(
+                filename,
+                line_number,
+                self._comes_from,
+                args_str,
+                opts,
+                constraint,
+            )
+
+
+def get_line_parser(finder):
+    # type: (Optional[PackageFinder]) -> LineParser
+    def parse_line(line):
+        # type: (Text) -> Tuple[str, Values]
+        # Build new parser for each line since it accumulates appendable
+        # options.
+        parser = build_parser()
+        defaults = parser.get_default_values()
+        defaults.index_url = None
+        if finder:
+            defaults.format_control = finder.format_control
+
+        args_str, options_str = break_args_options(line)
+        # Prior to 2.7.3, shlex cannot deal with unicode entries
+        if sys.version_info < (2, 7, 3):
+            # https://github.com/python/mypy/issues/1174
+            options_str = options_str.encode('utf8')  # type: ignore
+
+        # https://github.com/python/mypy/issues/1174
+        opts, _ = parser.parse_args(
+            shlex.split(options_str), defaults)  # type: ignore
+
+        return args_str, opts
+
+    return parse_line
+
+
+def break_args_options(line):
+    # type: (Text) -> Tuple[str, Text]
+    """Break up the line into an args and options string.  We only want to shlex
+    (and then optparse) the options, not the args.  args can contain markers
+    which are corrupted by shlex.
+    """
+    tokens = line.split(' ')
+    args = []
+    options = tokens[:]
+    for token in tokens:
+        if token.startswith('-') or token.startswith('--'):
+            break
+        else:
+            args.append(token)
+            options.pop(0)
+    return ' '.join(args), ' '.join(options)  # type: ignore
+
+
+class OptionParsingError(Exception):
+    def __init__(self, msg):
+        # type: (str) -> None
+        self.msg = msg
+
+
+def build_parser():
+    # type: () -> optparse.OptionParser
+    """
+    Return a parser for parsing requirement lines
+    """
+    parser = optparse.OptionParser(add_help_option=False)
+
+    option_factories = SUPPORTED_OPTIONS + SUPPORTED_OPTIONS_REQ
+    for option_factory in option_factories:
+        option = option_factory()
+        parser.add_option(option)
+
+    # By default optparse sys.exits on parsing errors. We want to wrap
+    # that in our own exception.
+    def parser_exit(self, msg):
+        # type: (Any, str) -> NoReturn
+        raise OptionParsingError(msg)
+    # NOTE: mypy disallows assigning to a method
+    #       https://github.com/python/mypy/issues/2427
+    parser.exit = parser_exit  # type: ignore
+
+    return parser
+
+
+def join_lines(lines_enum):
+    # type: (ReqFileLines) -> ReqFileLines
+    """Joins a line ending in '\' with the previous line (except when following
+    comments).  The joined line takes on the index of the first line.
+    """
+    primary_line_number = None
+    new_line = []  # type: List[Text]
+    for line_number, line in lines_enum:
+        if not line.endswith('\\') or COMMENT_RE.match(line):
+            if COMMENT_RE.match(line):
+                # this ensures comments are always matched later
+                line = ' ' + line
+            if new_line:
+                new_line.append(line)
+                yield primary_line_number, ''.join(new_line)
+                new_line = []
+            else:
+                yield line_number, line
+        else:
+            if not new_line:
+                primary_line_number = line_number
+            new_line.append(line.strip('\\'))
+
+    # last line contains \
+    if new_line:
+        yield primary_line_number, ''.join(new_line)
+
+    # TODO: handle space after '\'.
+
+
+def ignore_comments(lines_enum):
+    # type: (ReqFileLines) -> ReqFileLines
+    """
+    Strips comments and filter empty lines.
+    """
+    for line_number, line in lines_enum:
+        line = COMMENT_RE.sub('', line)
+        line = line.strip()
+        if line:
+            yield line_number, line
+
+
+def skip_regex(lines_enum, pattern):
+    # type: (ReqFileLines, str) -> ReqFileLines
+    """
+    Skip lines that match the provided pattern
+
+    Note: the regex pattern is only built once
+    """
+    matcher = re.compile(pattern)
+    lines_enum = filterfalse(lambda e: matcher.search(e[1]), lines_enum)
+    return lines_enum
+
+
+def expand_env_variables(lines_enum):
+    # type: (ReqFileLines) -> ReqFileLines
+    """Replace all environment variables that can be retrieved via `os.getenv`.
+
+    The only allowed format for environment variables defined in the
+    requirement file is `${MY_VARIABLE_1}` to ensure two things:
+
+    1. Strings that contain a `$` aren't accidentally (partially) expanded.
+    2. Ensure consistency across platforms for requirement files.
+
+    These points are the result of a discussion on the `github pull
+    request #3514 <https://github.com/pypa/pip/pull/3514>`_.
+
+    Valid characters in variable names follow the `POSIX standard
+    <http://pubs.opengroup.org/onlinepubs/9699919799/>`_ and are limited
+    to uppercase letter, digits and the `_` (underscore).
+    """
+    for line_number, line in lines_enum:
+        for env_var, var_name in ENV_VAR_RE.findall(line):
+            value = os.getenv(var_name)
+            if not value:
+                continue
+
+            line = line.replace(env_var, value)
+
+        yield line_number, line
+
+
+def get_file_content(url, session, comes_from=None):
+    # type: (str, PipSession, Optional[str]) -> Tuple[str, Text]
+    """Gets the content of a file; it may be a filename, file: URL, or
+    http: URL.  Returns (location, content).  Content is unicode.
+    Respects # -*- coding: declarations on the retrieved files.
+
+    :param url:         File path or url.
+    :param session:     PipSession instance.
+    :param comes_from:  Origin description of requirements.
+    """
+    scheme = get_url_scheme(url)
+
+    if scheme in ['http', 'https']:
+        # FIXME: catch some errors
+        resp = session.get(url)
+        resp.raise_for_status()
+        return resp.url, resp.text
+
+    elif scheme == 'file':
+        if comes_from and comes_from.startswith('http'):
+            raise InstallationError(
+                'Requirements file %s references URL %s, which is local'
+                % (comes_from, url))
+
+        path = url.split(':', 1)[1]
+        path = path.replace('\\', '/')
+        match = _url_slash_drive_re.match(path)
+        if match:
+            path = match.group(1) + ':' + path.split('|', 1)[1]
+        path = urllib_parse.unquote(path)
+        if path.startswith('/'):
+            path = '/' + path.lstrip('/')
+        url = path
+
+    try:
+        with open(url, 'rb') as f:
+            content = auto_decode(f.read())
+    except IOError as exc:
+        raise InstallationError(
+            'Could not open requirements file: %s' % str(exc)
+        )
+    return url, content
+
+
+_url_slash_drive_re = re.compile(r'/*([a-z])\|', re.I)

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/req/req_install.py

@@ -0,0 +1,830 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+import shutil
+import sys
+import zipfile
+
+from pip._vendor import pkg_resources, six
+from pip._vendor.packaging.requirements import Requirement
+from pip._vendor.packaging.utils import canonicalize_name
+from pip._vendor.packaging.version import Version
+from pip._vendor.packaging.version import parse as parse_version
+from pip._vendor.pep517.wrappers import Pep517HookCaller
+
+from pip._internal import pep425tags
+from pip._internal.build_env import NoOpBuildEnvironment
+from pip._internal.exceptions import InstallationError
+from pip._internal.locations import get_scheme
+from pip._internal.models.link import Link
+from pip._internal.operations.build.metadata import generate_metadata
+from pip._internal.operations.build.metadata_legacy import \
+    generate_metadata as generate_metadata_legacy
+from pip._internal.operations.install.editable_legacy import \
+    install_editable as install_editable_legacy
+from pip._internal.operations.install.legacy import install as install_legacy
+from pip._internal.operations.install.wheel import install_wheel
+from pip._internal.pyproject import load_pyproject_toml, make_pyproject_path
+from pip._internal.req.req_uninstall import UninstallPathSet
+from pip._internal.utils.deprecation import deprecated
+from pip._internal.utils.hashes import Hashes
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.marker_files import (
+    PIP_DELETE_MARKER_FILENAME,
+    has_delete_marker_file,
+    write_delete_marker_file,
+)
+from pip._internal.utils.misc import (
+    ask_path_exists,
+    backup_dir,
+    display_path,
+    dist_in_site_packages,
+    dist_in_usersite,
+    get_installed_version,
+    hide_url,
+    redact_auth_from_url,
+    rmtree,
+)
+from pip._internal.utils.packaging import get_metadata
+from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.virtualenv import running_under_virtualenv
+from pip._internal.vcs import vcs
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, Dict, Iterable, List, Optional, Sequence, Union,
+    )
+    from pip._internal.build_env import BuildEnvironment
+    from pip._internal.cache import WheelCache
+    from pip._internal.index.package_finder import PackageFinder
+    from pip._vendor.pkg_resources import Distribution
+    from pip._vendor.packaging.specifiers import SpecifierSet
+    from pip._vendor.packaging.markers import Marker
+
+
+logger = logging.getLogger(__name__)
+
+
+def _get_dist(metadata_directory):
+    # type: (str) -> Distribution
+    """Return a pkg_resources.Distribution for the provided
+    metadata directory.
+    """
+    dist_dir = metadata_directory.rstrip(os.sep)
+
+    # Determine the correct Distribution object type.
+    if dist_dir.endswith(".egg-info"):
+        dist_cls = pkg_resources.Distribution
+    else:
+        assert dist_dir.endswith(".dist-info")
+        dist_cls = pkg_resources.DistInfoDistribution
+
+    # Build a PathMetadata object, from path to metadata. :wink:
+    base_dir, dist_dir_name = os.path.split(dist_dir)
+    dist_name = os.path.splitext(dist_dir_name)[0]
+    metadata = pkg_resources.PathMetadata(base_dir, dist_dir)
+
+    return dist_cls(
+        base_dir,
+        project_name=dist_name,
+        metadata=metadata,
+    )
+
+
+class InstallRequirement(object):
+    """
+    Represents something that may be installed later on, may have information
+    about where to fetch the relevant requirement and also contains logic for
+    installing the said requirement.
+    """
+
+    def __init__(
+        self,
+        req,  # type: Optional[Requirement]
+        comes_from,  # type: Optional[Union[str, InstallRequirement]]
+        source_dir=None,  # type: Optional[str]
+        editable=False,  # type: bool
+        link=None,  # type: Optional[Link]
+        markers=None,  # type: Optional[Marker]
+        use_pep517=None,  # type: Optional[bool]
+        isolated=False,  # type: bool
+        options=None,  # type: Optional[Dict[str, Any]]
+        wheel_cache=None,  # type: Optional[WheelCache]
+        constraint=False,  # type: bool
+        extras=()  # type: Iterable[str]
+    ):
+        # type: (...) -> None
+        assert req is None or isinstance(req, Requirement), req
+        self.req = req
+        self.comes_from = comes_from
+        self.constraint = constraint
+        if source_dir is None:
+            self.source_dir = None  # type: Optional[str]
+        else:
+            self.source_dir = os.path.normpath(os.path.abspath(source_dir))
+        self.editable = editable
+
+        self._wheel_cache = wheel_cache
+        if link is None and req and req.url:
+            # PEP 508 URL requirement
+            link = Link(req.url)
+        self.link = self.original_link = link
+        # Path to any downloaded or already-existing package.
+        self.local_file_path = None  # type: Optional[str]
+        if self.link and self.link.is_file:
+            self.local_file_path = self.link.file_path
+
+        if extras:
+            self.extras = extras
+        elif req:
+            self.extras = {
+                pkg_resources.safe_extra(extra) for extra in req.extras
+            }
+        else:
+            self.extras = set()
+        if markers is None and req:
+            markers = req.marker
+        self.markers = markers
+
+        # This holds the pkg_resources.Distribution object if this requirement
+        # is already available:
+        self.satisfied_by = None  # type: Optional[Distribution]
+        # Whether the installation process should try to uninstall an existing
+        # distribution before installing this requirement.
+        self.should_reinstall = False
+        # Temporary build location
+        self._temp_build_dir = None  # type: Optional[TempDirectory]
+        # Set to True after successful installation
+        self.install_succeeded = None  # type: Optional[bool]
+        self.options = options if options else {}
+        # Set to True after successful preparation of this requirement
+        self.prepared = False
+        self.is_direct = False
+
+        self.isolated = isolated
+        self.build_env = NoOpBuildEnvironment()  # type: BuildEnvironment
+
+        # For PEP 517, the directory where we request the project metadata
+        # gets stored. We need this to pass to build_wheel, so the backend
+        # can ensure that the wheel matches the metadata (see the PEP for
+        # details).
+        self.metadata_directory = None  # type: Optional[str]
+
+        # The static build requirements (from pyproject.toml)
+        self.pyproject_requires = None  # type: Optional[List[str]]
+
+        # Build requirements that we will check are available
+        self.requirements_to_check = []  # type: List[str]
+
+        # The PEP 517 backend we should use to build the project
+        self.pep517_backend = None  # type: Optional[Pep517HookCaller]
+
+        # Are we using PEP 517 for this requirement?
+        # After pyproject.toml has been loaded, the only valid values are True
+        # and False. Before loading, None is valid (meaning "use the default").
+        # Setting an explicit value before loading pyproject.toml is supported,
+        # but after loading this flag should be treated as read only.
+        self.use_pep517 = use_pep517
+
+    def __str__(self):
+        # type: () -> str
+        if self.req:
+            s = str(self.req)
+            if self.link:
+                s += ' from %s' % redact_auth_from_url(self.link.url)
+        elif self.link:
+            s = redact_auth_from_url(self.link.url)
+        else:
+            s = '<InstallRequirement>'
+        if self.satisfied_by is not None:
+            s += ' in %s' % display_path(self.satisfied_by.location)
+        if self.comes_from:
+            if isinstance(self.comes_from, six.string_types):
+                comes_from = self.comes_from  # type: Optional[str]
+            else:
+                comes_from = self.comes_from.from_path()
+            if comes_from:
+                s += ' (from %s)' % comes_from
+        return s
+
+    def __repr__(self):
+        # type: () -> str
+        return '<%s object: %s editable=%r>' % (
+            self.__class__.__name__, str(self), self.editable)
+
+    def format_debug(self):
+        # type: () -> str
+        """An un-tested helper for getting state, for debugging.
+        """
+        attributes = vars(self)
+        names = sorted(attributes)
+
+        state = (
+            "{}={!r}".format(attr, attributes[attr]) for attr in sorted(names)
+        )
+        return '<{name} object: {{{state}}}>'.format(
+            name=self.__class__.__name__,
+            state=", ".join(state),
+        )
+
+    def populate_link(self, finder, upgrade, require_hashes):
+        # type: (PackageFinder, bool, bool) -> None
+        """Ensure that if a link can be found for this, that it is found.
+
+        Note that self.link may still be None - if Upgrade is False and the
+        requirement is already installed.
+
+        If require_hashes is True, don't use the wheel cache, because cached
+        wheels, always built locally, have different hashes than the files
+        downloaded from the index server and thus throw false hash mismatches.
+        Furthermore, cached wheels at present have undeterministic contents due
+        to file modification times.
+        """
+        if self.link is None:
+            self.link = finder.find_requirement(self, upgrade)
+        if self._wheel_cache is not None and not require_hashes:
+            old_link = self.link
+            supported_tags = pep425tags.get_supported()
+            self.link = self._wheel_cache.get(
+                link=self.link,
+                package_name=self.name,
+                supported_tags=supported_tags,
+            )
+            if old_link != self.link:
+                logger.debug('Using cached wheel link: %s', self.link)
+
+    # Things that are valid for all kinds of requirements?
+    @property
+    def name(self):
+        # type: () -> Optional[str]
+        if self.req is None:
+            return None
+        return six.ensure_str(pkg_resources.safe_name(self.req.name))
+
+    @property
+    def specifier(self):
+        # type: () -> SpecifierSet
+        return self.req.specifier
+
+    @property
+    def is_pinned(self):
+        # type: () -> bool
+        """Return whether I am pinned to an exact version.
+
+        For example, some-package==1.2 is pinned; some-package>1.2 is not.
+        """
+        specifiers = self.specifier
+        return (len(specifiers) == 1 and
+                next(iter(specifiers)).operator in {'==', '==='})
+
+    @property
+    def installed_version(self):
+        # type: () -> Optional[str]
+        return get_installed_version(self.name)
+
+    def match_markers(self, extras_requested=None):
+        # type: (Optional[Iterable[str]]) -> bool
+        if not extras_requested:
+            # Provide an extra to safely evaluate the markers
+            # without matching any extra
+            extras_requested = ('',)
+        if self.markers is not None:
+            return any(
+                self.markers.evaluate({'extra': extra})
+                for extra in extras_requested)
+        else:
+            return True
+
+    @property
+    def has_hash_options(self):
+        # type: () -> bool
+        """Return whether any known-good hashes are specified as options.
+
+        These activate --require-hashes mode; hashes specified as part of a
+        URL do not.
+
+        """
+        return bool(self.options.get('hashes', {}))
+
+    def hashes(self, trust_internet=True):
+        # type: (bool) -> Hashes
+        """Return a hash-comparer that considers my option- and URL-based
+        hashes to be known-good.
+
+        Hashes in URLs--ones embedded in the requirements file, not ones
+        downloaded from an index server--are almost peers with ones from
+        flags. They satisfy --require-hashes (whether it was implicitly or
+        explicitly activated) but do not activate it. md5 and sha224 are not
+        allowed in flags, which should nudge people toward good algos. We
+        always OR all hashes together, even ones from URLs.
+
+        :param trust_internet: Whether to trust URL-based (#md5=...) hashes
+            downloaded from the internet, as by populate_link()
+
+        """
+        good_hashes = self.options.get('hashes', {}).copy()
+        link = self.link if trust_internet else self.original_link
+        if link and link.hash:
+            good_hashes.setdefault(link.hash_name, []).append(link.hash)
+        return Hashes(good_hashes)
+
+    def from_path(self):
+        # type: () -> Optional[str]
+        """Format a nice indicator to show where this "comes from"
+        """
+        if self.req is None:
+            return None
+        s = str(self.req)
+        if self.comes_from:
+            if isinstance(self.comes_from, six.string_types):
+                comes_from = self.comes_from
+            else:
+                comes_from = self.comes_from.from_path()
+            if comes_from:
+                s += '->' + comes_from
+        return s
+
+    def ensure_build_location(self, build_dir):
+        # type: (str) -> str
+        assert build_dir is not None
+        if self._temp_build_dir is not None:
+            assert self._temp_build_dir.path
+            return self._temp_build_dir.path
+        if self.req is None:
+            # Some systems have /tmp as a symlink which confuses custom
+            # builds (such as numpy). Thus, we ensure that the real path
+            # is returned.
+            self._temp_build_dir = TempDirectory(kind="req-build")
+
+            return self._temp_build_dir.path
+        if self.editable:
+            name = self.name.lower()
+        else:
+            name = self.name
+        # FIXME: Is there a better place to create the build_dir? (hg and bzr
+        # need this)
+        if not os.path.exists(build_dir):
+            logger.debug('Creating directory %s', build_dir)
+            os.makedirs(build_dir)
+            write_delete_marker_file(build_dir)
+        return os.path.join(build_dir, name)
+
+    def _set_requirement(self):
+        # type: () -> None
+        """Set requirement after generating metadata.
+        """
+        assert self.req is None
+        assert self.metadata is not None
+        assert self.source_dir is not None
+
+        # Construct a Requirement object from the generated metadata
+        if isinstance(parse_version(self.metadata["Version"]), Version):
+            op = "=="
+        else:
+            op = "==="
+
+        self.req = Requirement(
+            "".join([
+                self.metadata["Name"],
+                op,
+                self.metadata["Version"],
+            ])
+        )
+
+    def warn_on_mismatching_name(self):
+        # type: () -> None
+        metadata_name = canonicalize_name(self.metadata["Name"])
+        if canonicalize_name(self.req.name) == metadata_name:
+            # Everything is fine.
+            return
+
+        # If we're here, there's a mismatch. Log a warning about it.
+        logger.warning(
+            'Generating metadata for package %s '
+            'produced metadata for project name %s. Fix your '
+            '#egg=%s fragments.',
+            self.name, metadata_name, self.name
+        )
+        self.req = Requirement(metadata_name)
+
+    def remove_temporary_source(self):
+        # type: () -> None
+        """Remove the source files from this requirement, if they are marked
+        for deletion"""
+        if self.source_dir and has_delete_marker_file(self.source_dir):
+            logger.debug('Removing source in %s', self.source_dir)
+            rmtree(self.source_dir)
+        self.source_dir = None
+        if self._temp_build_dir:
+            self._temp_build_dir.cleanup()
+            self._temp_build_dir = None
+        self.build_env.cleanup()
+
+    def check_if_exists(self, use_user_site):
+        # type: (bool) -> None
+        """Find an installed distribution that satisfies or conflicts
+        with this requirement, and set self.satisfied_by or
+        self.should_reinstall appropriately.
+        """
+        if self.req is None:
+            return
+        # get_distribution() will resolve the entire list of requirements
+        # anyway, and we've already determined that we need the requirement
+        # in question, so strip the marker so that we don't try to
+        # evaluate it.
+        no_marker = Requirement(str(self.req))
+        no_marker.marker = None
+        try:
+            self.satisfied_by = pkg_resources.get_distribution(str(no_marker))
+        except pkg_resources.DistributionNotFound:
+            return
+        except pkg_resources.VersionConflict:
+            existing_dist = pkg_resources.get_distribution(
+                self.req.name
+            )
+            if use_user_site:
+                if dist_in_usersite(existing_dist):
+                    self.should_reinstall = True
+                elif (running_under_virtualenv() and
+                        dist_in_site_packages(existing_dist)):
+                    raise InstallationError(
+                        "Will not install to the user site because it will "
+                        "lack sys.path precedence to %s in %s" %
+                        (existing_dist.project_name, existing_dist.location)
+                    )
+            else:
+                self.should_reinstall = True
+        else:
+            if self.editable and self.satisfied_by:
+                self.should_reinstall = True
+                # when installing editables, nothing pre-existing should ever
+                # satisfy
+                self.satisfied_by = None
+
+    # Things valid for wheels
+    @property
+    def is_wheel(self):
+        # type: () -> bool
+        if not self.link:
+            return False
+        return self.link.is_wheel
+
+    # Things valid for sdists
+    @property
+    def unpacked_source_directory(self):
+        # type: () -> str
+        return os.path.join(
+            self.source_dir,
+            self.link and self.link.subdirectory_fragment or '')
+
+    @property
+    def setup_py_path(self):
+        # type: () -> str
+        assert self.source_dir, "No source dir for %s" % self
+        setup_py = os.path.join(self.unpacked_source_directory, 'setup.py')
+
+        # Python2 __file__ should not be unicode
+        if six.PY2 and isinstance(setup_py, six.text_type):
+            setup_py = setup_py.encode(sys.getfilesystemencoding())
+
+        return setup_py
+
+    @property
+    def pyproject_toml_path(self):
+        # type: () -> str
+        assert self.source_dir, "No source dir for %s" % self
+        return make_pyproject_path(self.unpacked_source_directory)
+
+    def load_pyproject_toml(self):
+        # type: () -> None
+        """Load the pyproject.toml file.
+
+        After calling this routine, all of the attributes related to PEP 517
+        processing for this requirement have been set. In particular, the
+        use_pep517 attribute can be used to determine whether we should
+        follow the PEP 517 or legacy (setup.py) code path.
+        """
+        pyproject_toml_data = load_pyproject_toml(
+            self.use_pep517,
+            self.pyproject_toml_path,
+            self.setup_py_path,
+            str(self)
+        )
+
+        if pyproject_toml_data is None:
+            self.use_pep517 = False
+            return
+
+        self.use_pep517 = True
+        requires, backend, check, backend_path = pyproject_toml_data
+        self.requirements_to_check = check
+        self.pyproject_requires = requires
+        self.pep517_backend = Pep517HookCaller(
+            self.unpacked_source_directory, backend, backend_path=backend_path,
+        )
+
+    def _generate_metadata(self):
+        # type: () -> str
+        """Invokes metadata generator functions, with the required arguments.
+        """
+        if not self.use_pep517:
+            assert self.unpacked_source_directory
+
+            return generate_metadata_legacy(
+                build_env=self.build_env,
+                setup_py_path=self.setup_py_path,
+                source_dir=self.unpacked_source_directory,
+                editable=self.editable,
+                isolated=self.isolated,
+                details=self.name or "from {}".format(self.link)
+            )
+
+        assert self.pep517_backend is not None
+
+        return generate_metadata(
+            build_env=self.build_env,
+            backend=self.pep517_backend,
+        )
+
+    def prepare_metadata(self):
+        # type: () -> None
+        """Ensure that project metadata is available.
+
+        Under PEP 517, call the backend hook to prepare the metadata.
+        Under legacy processing, call setup.py egg-info.
+        """
+        assert self.source_dir
+
+        with indent_log():
+            self.metadata_directory = self._generate_metadata()
+
+        # Act on the newly generated metadata, based on the name and version.
+        if not self.name:
+            self._set_requirement()
+        else:
+            self.warn_on_mismatching_name()
+
+        self.assert_source_matches_version()
+
+    @property
+    def metadata(self):
+        # type: () -> Any
+        if not hasattr(self, '_metadata'):
+            self._metadata = get_metadata(self.get_dist())
+
+        return self._metadata
+
+    def get_dist(self):
+        # type: () -> Distribution
+        return _get_dist(self.metadata_directory)
+
+    def assert_source_matches_version(self):
+        # type: () -> None
+        assert self.source_dir
+        version = self.metadata['version']
+        if self.req.specifier and version not in self.req.specifier:
+            logger.warning(
+                'Requested %s, but installing version %s',
+                self,
+                version,
+            )
+        else:
+            logger.debug(
+                'Source in %s has version %s, which satisfies requirement %s',
+                display_path(self.source_dir),
+                version,
+                self,
+            )
+
+    # For both source distributions and editables
+    def ensure_has_source_dir(self, parent_dir):
+        # type: (str) -> None
+        """Ensure that a source_dir is set.
+
+        This will create a temporary build dir if the name of the requirement
+        isn't known yet.
+
+        :param parent_dir: The ideal pip parent_dir for the source_dir.
+            Generally src_dir for editables and build_dir for sdists.
+        :return: self.source_dir
+        """
+        if self.source_dir is None:
+            self.source_dir = self.ensure_build_location(parent_dir)
+
+    # For editable installations
+    def update_editable(self, obtain=True):
+        # type: (bool) -> None
+        if not self.link:
+            logger.debug(
+                "Cannot update repository at %s; repository location is "
+                "unknown",
+                self.source_dir,
+            )
+            return
+        assert self.editable
+        assert self.source_dir
+        if self.link.scheme == 'file':
+            # Static paths don't get updated
+            return
+        assert '+' in self.link.url, "bad url: %r" % self.link.url
+        vc_type, url = self.link.url.split('+', 1)
+        vcs_backend = vcs.get_backend(vc_type)
+        if vcs_backend:
+            if not self.link.is_vcs:
+                reason = (
+                    "This form of VCS requirement is being deprecated: {}."
+                ).format(
+                    self.link.url
+                )
+                replacement = None
+                if self.link.url.startswith("git+git@"):
+                    replacement = (
+                        "git+https://git@example.com/..., "
+                        "git+ssh://git@example.com/..., "
+                        "or the insecure git+git://git@example.com/..."
+                    )
+                deprecated(reason, replacement, gone_in="21.0", issue=7554)
+            hidden_url = hide_url(self.link.url)
+            if obtain:
+                vcs_backend.obtain(self.source_dir, url=hidden_url)
+            else:
+                vcs_backend.export(self.source_dir, url=hidden_url)
+        else:
+            assert 0, (
+                'Unexpected version control type (in %s): %s'
+                % (self.link, vc_type))
+
+    # Top-level Actions
+    def uninstall(self, auto_confirm=False, verbose=False):
+        # type: (bool, bool) -> Optional[UninstallPathSet]
+        """
+        Uninstall the distribution currently satisfying this requirement.
+
+        Prompts before removing or modifying files unless
+        ``auto_confirm`` is True.
+
+        Refuses to delete or modify files outside of ``sys.prefix`` -
+        thus uninstallation within a virtual environment can only
+        modify that virtual environment, even if the virtualenv is
+        linked to global site-packages.
+
+        """
+        assert self.req
+        try:
+            dist = pkg_resources.get_distribution(self.req.name)
+        except pkg_resources.DistributionNotFound:
+            logger.warning("Skipping %s as it is not installed.", self.name)
+            return None
+        else:
+            logger.info('Found existing installation: %s', dist)
+
+        uninstalled_pathset = UninstallPathSet.from_dist(dist)
+        uninstalled_pathset.remove(auto_confirm, verbose)
+        return uninstalled_pathset
+
+    def _get_archive_name(self, path, parentdir, rootdir):
+        # type: (str, str, str) -> str
+
+        def _clean_zip_name(name, prefix):
+            # type: (str, str) -> str
+            assert name.startswith(prefix + os.path.sep), (
+                "name %r doesn't start with prefix %r" % (name, prefix)
+            )
+            name = name[len(prefix) + 1:]
+            name = name.replace(os.path.sep, '/')
+            return name
+
+        path = os.path.join(parentdir, path)
+        name = _clean_zip_name(path, rootdir)
+        return self.name + '/' + name
+
+    def archive(self, build_dir):
+        # type: (str) -> None
+        """Saves archive to provided build_dir.
+
+        Used for saving downloaded VCS requirements as part of `pip download`.
+        """
+        assert self.source_dir
+
+        create_archive = True
+        archive_name = '%s-%s.zip' % (self.name, self.metadata["version"])
+        archive_path = os.path.join(build_dir, archive_name)
+
+        if os.path.exists(archive_path):
+            response = ask_path_exists(
+                'The file %s exists. (i)gnore, (w)ipe, (b)ackup, (a)bort ' %
+                display_path(archive_path), ('i', 'w', 'b', 'a'))
+            if response == 'i':
+                create_archive = False
+            elif response == 'w':
+                logger.warning('Deleting %s', display_path(archive_path))
+                os.remove(archive_path)
+            elif response == 'b':
+                dest_file = backup_dir(archive_path)
+                logger.warning(
+                    'Backing up %s to %s',
+                    display_path(archive_path),
+                    display_path(dest_file),
+                )
+                shutil.move(archive_path, dest_file)
+            elif response == 'a':
+                sys.exit(-1)
+
+        if not create_archive:
+            return
+
+        zip_output = zipfile.ZipFile(
+            archive_path, 'w', zipfile.ZIP_DEFLATED, allowZip64=True,
+        )
+        with zip_output:
+            dir = os.path.normcase(
+                os.path.abspath(self.unpacked_source_directory)
+            )
+            for dirpath, dirnames, filenames in os.walk(dir):
+                if 'pip-egg-info' in dirnames:
+                    dirnames.remove('pip-egg-info')
+                for dirname in dirnames:
+                    dir_arcname = self._get_archive_name(
+                        dirname, parentdir=dirpath, rootdir=dir,
+                    )
+                    zipdir = zipfile.ZipInfo(dir_arcname + '/')
+                    zipdir.external_attr = 0x1ED << 16  # 0o755
+                    zip_output.writestr(zipdir, '')
+                for filename in filenames:
+                    if filename == PIP_DELETE_MARKER_FILENAME:
+                        continue
+                    file_arcname = self._get_archive_name(
+                        filename, parentdir=dirpath, rootdir=dir,
+                    )
+                    filename = os.path.join(dirpath, filename)
+                    zip_output.write(filename, file_arcname)
+
+        logger.info('Saved %s', display_path(archive_path))
+
+    def install(
+        self,
+        install_options,  # type: List[str]
+        global_options=None,  # type: Optional[Sequence[str]]
+        root=None,  # type: Optional[str]
+        home=None,  # type: Optional[str]
+        prefix=None,  # type: Optional[str]
+        warn_script_location=True,  # type: bool
+        use_user_site=False,  # type: bool
+        pycompile=True  # type: bool
+    ):
+        # type: (...) -> None
+        scheme = get_scheme(
+            self.name,
+            user=use_user_site,
+            home=home,
+            root=root,
+            isolated=self.isolated,
+            prefix=prefix,
+        )
+
+        global_options = global_options if global_options is not None else []
+        if self.editable:
+            install_editable_legacy(
+                install_options,
+                global_options,
+                prefix=prefix,
+                home=home,
+                use_user_site=use_user_site,
+                name=self.name,
+                setup_py_path=self.setup_py_path,
+                isolated=self.isolated,
+                build_env=self.build_env,
+                unpacked_source_directory=self.unpacked_source_directory,
+            )
+            self.install_succeeded = True
+            return
+
+        if self.is_wheel:
+            assert self.local_file_path
+            install_wheel(
+                self.name,
+                self.local_file_path,
+                scheme=scheme,
+                req_description=str(self.req),
+                pycompile=pycompile,
+                warn_script_location=warn_script_location,
+            )
+            self.install_succeeded = True
+            return
+
+        install_legacy(
+            self,
+            install_options=install_options,
+            global_options=global_options,
+            root=root,
+            home=home,
+            prefix=prefix,
+            use_user_site=use_user_site,
+            pycompile=pycompile,
+            scheme=scheme,
+        )

Mail/mailvenv/lib/python3.8/site-packages/pip/_internal/req/req_set.py

@@ -0,0 +1,209 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import logging
+from collections import OrderedDict
+
+from pip._vendor.packaging.utils import canonicalize_name
+
+from pip._internal import pep425tags
+from pip._internal.exceptions import InstallationError
+from pip._internal.models.wheel import Wheel
+from pip._internal.utils.logging import indent_log
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Dict, Iterable, List, Optional, Tuple
+    from pip._internal.req.req_install import InstallRequirement
+
+
+logger = logging.getLogger(__name__)
+
+
+class RequirementSet(object):
+
+    def __init__(self, check_supported_wheels=True):
+        # type: (bool) -> None
+        """Create a RequirementSet.
+        """
+
+        self.requirements = OrderedDict()  # type: Dict[str, InstallRequirement]  # noqa: E501
+        self.check_supported_wheels = check_supported_wheels
+
+        self.unnamed_requirements = []  # type: List[InstallRequirement]
+        self.successfully_downloaded = []  # type: List[InstallRequirement]
+        self.reqs_to_cleanup = []  # type: List[InstallRequirement]
+
+    def __str__(self):
+        # type: () -> str
+        requirements = sorted(
+            (req for req in self.requirements.values() if not req.comes_from),
+            key=lambda req: canonicalize_name(req.name),
+        )
+        return ' '.join(str(req.req) for req in requirements)
+
+    def __repr__(self):
+        # type: () -> str
+        requirements = sorted(
+            self.requirements.values(),
+            key=lambda req: canonicalize_name(req.name),
+        )
+
+        format_string = '<{classname} object; {count} requirement(s): {reqs}>'
+        return format_string.format(
+            classname=self.__class__.__name__,
+            count=len(requirements),
+            reqs=', '.join(str(req.req) for req in requirements),
+        )
+
+    def add_unnamed_requirement(self, install_req):
+        # type: (InstallRequirement) -> None
+        assert not install_req.name
+        self.unnamed_requirements.append(install_req)
+
+    def add_named_requirement(self, install_req):
+        # type: (InstallRequirement) -> None
+        assert install_req.name
+
+        project_name = canonicalize_name(install_req.name)
+        self.requirements[project_name] = install_req
+
+    def add_requirement(
+        self,
+        install_req,  # type: InstallRequirement
+        parent_req_name=None,  # type: Optional[str]
+        extras_requested=None  # type: Optional[Iterable[str]]
+    ):
+        # type: (...) -> Tuple[List[InstallRequirement], Optional[InstallRequirement]]  # noqa: E501
+        """Add install_req as a requirement to install.
+
+        :param parent_req_name: The name of the requirement that needed this
+            added. The name is used because when multiple unnamed requirements
+            resolve to the same name, we could otherwise end up with dependency
+            links that point outside the Requirements set. parent_req must
+            already be added. Note that None implies that this is a user
+            supplied requirement, vs an inferred one.
+        :param extras_requested: an iterable of extras used to evaluate the
+            environment markers.
+        :return: Additional requirements to scan. That is either [] if
+            the requirement is not applicable, or [install_req] if the
+            requirement is applicable and has just been added.
+        """
+        # If the markers do not match, ignore this requirement.
+        if not install_req.match_markers(extras_requested):
+            logger.info(
+                "Ignoring %s: markers '%s' don't match your environment",
+                install_req.name, install_req.markers,
+            )
+            return [], None
+
+        # If the wheel is not supported, raise an error.
+        # Should check this after filtering out based on environment markers to
+        # allow specifying different wheels based on the environment/OS, in a
+        # single requirements file.
+        if install_req.link and install_req.link.is_wheel:
+            wheel = Wheel(install_req.link.filename)
+            tags = pep425tags.get_supported()
+            if (self.check_supported_wheels and not wheel.supported(tags)):
+                raise InstallationError(
+                    "%s is not a supported wheel on this platform." %
+                    wheel.filename
+                )
+
+        # This next bit is really a sanity check.
+        assert install_req.is_direct == (parent_req_name is None), (
+            "a direct req shouldn't have a parent and also, "
+            "a non direct req should have a parent"
+        )
+
+        # Unnamed requirements are scanned again and the requirement won't be
+        # added as a dependency until after scanning.
+        if not install_req.name:
+            self.add_unnamed_requirement(install_req)
+            return [install_req], None
+
+        try:
+            existing_req = self.get_requirement(install_req.name)
+        except KeyError:
+            existing_req = None
+
+        has_conflicting_requirement = (
+            parent_req_name is None and
+            existing_req and
+            not existing_req.constraint and
+            existing_req.extras == install_req.extras and
+            existing_req.req.specifier != install_req.req.specifier
+        )
+        if has_conflicting_requirement:
+            raise InstallationError(
+                "Double requirement given: %s (already in %s, name=%r)"
+                % (install_req, existing_req, install_req.name)
+            )
+
+        # When no existing requirement exists, add the requirement as a
+        # dependency and it will be scanned again after.
+        if not existing_req:
+            self.add_named_requirement(install_req)
+            # We'd want to rescan this requirement later
+            return [install_req], install_req
+
+        # Assume there's no need to scan, and that we've already
+        # encountered this for scanning.
+        if install_req.constraint or not existing_req.constraint:
+            return [], existing_req
+
+        does_not_satisfy_constraint = (
+            install_req.link and
+            not (
+                existing_req.link and
+                install_req.link.path == existing_req.link.path
+            )
+        )
+        if does_not_satisfy_constraint:
+            self.reqs_to_cleanup.append(install_req)
+            raise InstallationError(
+                "Could not satisfy constraints for '%s': "
+                "installation from path or url cannot be "
+                "constrained to a version" % install_req.name,
+            )
+        # If we're now installing a constraint, mark the existing
+        # object for real installation.
+        existing_req.constraint = False
+        existing_req.extras = tuple(sorted(
+            set(existing_req.extras) | set(install_req.extras)
+        ))
+        logger.debug(
+            "Setting %s extras to: %s",
+            existing_req, existing_req.extras,
+        )
+        # Return the existing requirement for addition to the parent and
+        # scanning again.
+        return [existing_req], existing_req
+
+    def has_requirement(self, name):
+        # type: (str) -> bool
+        project_name = canonicalize_name(name)
+
+        return (
+            project_name in self.requirements and
+            not self.requirements[project_name].constraint
+        )
+
+    def get_requirement(self, name):
+        # type: (str) -> InstallRequirement
+        project_name = canonicalize_name(name)
+
+        if project_name in self.requirements:
+            return self.requirements[project_name]
+
+        raise KeyError("No project with the name %r" % name)
+
+    def cleanup_files(self):
+        # type: () -> None
+        """Clean up files, remove builds."""
+        logger.debug('Cleaning up...')
+        with indent_log():
+            for req in self.reqs_to_cleanup:
+                req.remove_temporary_source()