tldr: refactoring

venv/lib/python3.7/site-packages/pip/_vendor/packaging/__about__.py

@@ -0,0 +1,27 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+__all__ = [
+    "__title__",
+    "__summary__",
+    "__uri__",
+    "__version__",
+    "__author__",
+    "__email__",
+    "__license__",
+    "__copyright__",
+]
+
+__title__ = "packaging"
+__summary__ = "Core utilities for Python packages"
+__uri__ = "https://github.com/pypa/packaging"
+
+__version__ = "19.2"
+
+__author__ = "Donald Stufft and individual contributors"
+__email__ = "donald@stufft.io"
+
+__license__ = "BSD or Apache License, Version 2.0"
+__copyright__ = "Copyright 2014-2019 %s" % __author__

venv/lib/python3.7/site-packages/pip/_vendor/packaging/__init__.py

@@ -0,0 +1,26 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+from .__about__ import (
+    __author__,
+    __copyright__,
+    __email__,
+    __license__,
+    __summary__,
+    __title__,
+    __uri__,
+    __version__,
+)
+
+__all__ = [
+    "__title__",
+    "__summary__",
+    "__uri__",
+    "__version__",
+    "__author__",
+    "__email__",
+    "__license__",
+    "__copyright__",
+]

venv/lib/python3.7/site-packages/pip/_vendor/packaging/_compat.py

@@ -0,0 +1,31 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import sys
+
+
+PY2 = sys.version_info[0] == 2
+PY3 = sys.version_info[0] == 3
+
+# flake8: noqa
+
+if PY3:
+    string_types = (str,)
+else:
+    string_types = (basestring,)
+
+
+def with_metaclass(meta, *bases):
+    """
+    Create a base class with a metaclass.
+    """
+    # This requires a bit of explanation: the basic idea is to make a dummy
+    # metaclass for one level of class instantiation that replaces itself with
+    # the actual metaclass.
+    class metaclass(meta):
+        def __new__(cls, name, this_bases, d):
+            return meta(name, bases, d)
+
+    return type.__new__(metaclass, "temporary_class", (), {})

venv/lib/python3.7/site-packages/pip/_vendor/packaging/_structures.py

@@ -0,0 +1,68 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+
+class Infinity(object):
+    def __repr__(self):
+        return "Infinity"
+
+    def __hash__(self):
+        return hash(repr(self))
+
+    def __lt__(self, other):
+        return False
+
+    def __le__(self, other):
+        return False
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__)
+
+    def __ne__(self, other):
+        return not isinstance(other, self.__class__)
+
+    def __gt__(self, other):
+        return True
+
+    def __ge__(self, other):
+        return True
+
+    def __neg__(self):
+        return NegativeInfinity
+
+
+Infinity = Infinity()
+
+
+class NegativeInfinity(object):
+    def __repr__(self):
+        return "-Infinity"
+
+    def __hash__(self):
+        return hash(repr(self))
+
+    def __lt__(self, other):
+        return True
+
+    def __le__(self, other):
+        return True
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__)
+
+    def __ne__(self, other):
+        return not isinstance(other, self.__class__)
+
+    def __gt__(self, other):
+        return False
+
+    def __ge__(self, other):
+        return False
+
+    def __neg__(self):
+        return Infinity
+
+
+NegativeInfinity = NegativeInfinity()

venv/lib/python3.7/site-packages/pip/_vendor/packaging/markers.py

@@ -0,0 +1,296 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import operator
+import os
+import platform
+import sys
+
+from pip._vendor.pyparsing import ParseException, ParseResults, stringStart, stringEnd
+from pip._vendor.pyparsing import ZeroOrMore, Group, Forward, QuotedString
+from pip._vendor.pyparsing import Literal as L  # noqa
+
+from ._compat import string_types
+from .specifiers import Specifier, InvalidSpecifier
+
+
+__all__ = [
+    "InvalidMarker",
+    "UndefinedComparison",
+    "UndefinedEnvironmentName",
+    "Marker",
+    "default_environment",
+]
+
+
+class InvalidMarker(ValueError):
+    """
+    An invalid marker was found, users should refer to PEP 508.
+    """
+
+
+class UndefinedComparison(ValueError):
+    """
+    An invalid operation was attempted on a value that doesn't support it.
+    """
+
+
+class UndefinedEnvironmentName(ValueError):
+    """
+    A name was attempted to be used that does not exist inside of the
+    environment.
+    """
+
+
+class Node(object):
+    def __init__(self, value):
+        self.value = value
+
+    def __str__(self):
+        return str(self.value)
+
+    def __repr__(self):
+        return "<{0}({1!r})>".format(self.__class__.__name__, str(self))
+
+    def serialize(self):
+        raise NotImplementedError
+
+
+class Variable(Node):
+    def serialize(self):
+        return str(self)
+
+
+class Value(Node):
+    def serialize(self):
+        return '"{0}"'.format(self)
+
+
+class Op(Node):
+    def serialize(self):
+        return str(self)
+
+
+VARIABLE = (
+    L("implementation_version")
+    | L("platform_python_implementation")
+    | L("implementation_name")
+    | L("python_full_version")
+    | L("platform_release")
+    | L("platform_version")
+    | L("platform_machine")
+    | L("platform_system")
+    | L("python_version")
+    | L("sys_platform")
+    | L("os_name")
+    | L("os.name")
+    | L("sys.platform")  # PEP-345
+    | L("platform.version")  # PEP-345
+    | L("platform.machine")  # PEP-345
+    | L("platform.python_implementation")  # PEP-345
+    | L("python_implementation")  # PEP-345
+    | L("extra")  # undocumented setuptools legacy
+)
+ALIASES = {
+    "os.name": "os_name",
+    "sys.platform": "sys_platform",
+    "platform.version": "platform_version",
+    "platform.machine": "platform_machine",
+    "platform.python_implementation": "platform_python_implementation",
+    "python_implementation": "platform_python_implementation",
+}
+VARIABLE.setParseAction(lambda s, l, t: Variable(ALIASES.get(t[0], t[0])))
+
+VERSION_CMP = (
+    L("===") | L("==") | L(">=") | L("<=") | L("!=") | L("~=") | L(">") | L("<")
+)
+
+MARKER_OP = VERSION_CMP | L("not in") | L("in")
+MARKER_OP.setParseAction(lambda s, l, t: Op(t[0]))
+
+MARKER_VALUE = QuotedString("'") | QuotedString('"')
+MARKER_VALUE.setParseAction(lambda s, l, t: Value(t[0]))
+
+BOOLOP = L("and") | L("or")
+
+MARKER_VAR = VARIABLE | MARKER_VALUE
+
+MARKER_ITEM = Group(MARKER_VAR + MARKER_OP + MARKER_VAR)
+MARKER_ITEM.setParseAction(lambda s, l, t: tuple(t[0]))
+
+LPAREN = L("(").suppress()
+RPAREN = L(")").suppress()
+
+MARKER_EXPR = Forward()
+MARKER_ATOM = MARKER_ITEM | Group(LPAREN + MARKER_EXPR + RPAREN)
+MARKER_EXPR << MARKER_ATOM + ZeroOrMore(BOOLOP + MARKER_EXPR)
+
+MARKER = stringStart + MARKER_EXPR + stringEnd
+
+
+def _coerce_parse_result(results):
+    if isinstance(results, ParseResults):
+        return [_coerce_parse_result(i) for i in results]
+    else:
+        return results
+
+
+def _format_marker(marker, first=True):
+    assert isinstance(marker, (list, tuple, string_types))
+
+    # Sometimes we have a structure like [[...]] which is a single item list
+    # where the single item is itself it's own list. In that case we want skip
+    # the rest of this function so that we don't get extraneous () on the
+    # outside.
+    if (
+        isinstance(marker, list)
+        and len(marker) == 1
+        and isinstance(marker[0], (list, tuple))
+    ):
+        return _format_marker(marker[0])
+
+    if isinstance(marker, list):
+        inner = (_format_marker(m, first=False) for m in marker)
+        if first:
+            return " ".join(inner)
+        else:
+            return "(" + " ".join(inner) + ")"
+    elif isinstance(marker, tuple):
+        return " ".join([m.serialize() for m in marker])
+    else:
+        return marker
+
+
+_operators = {
+    "in": lambda lhs, rhs: lhs in rhs,
+    "not in": lambda lhs, rhs: lhs not in rhs,
+    "<": operator.lt,
+    "<=": operator.le,
+    "==": operator.eq,
+    "!=": operator.ne,
+    ">=": operator.ge,
+    ">": operator.gt,
+}
+
+
+def _eval_op(lhs, op, rhs):
+    try:
+        spec = Specifier("".join([op.serialize(), rhs]))
+    except InvalidSpecifier:
+        pass
+    else:
+        return spec.contains(lhs)
+
+    oper = _operators.get(op.serialize())
+    if oper is None:
+        raise UndefinedComparison(
+            "Undefined {0!r} on {1!r} and {2!r}.".format(op, lhs, rhs)
+        )
+
+    return oper(lhs, rhs)
+
+
+_undefined = object()
+
+
+def _get_env(environment, name):
+    value = environment.get(name, _undefined)
+
+    if value is _undefined:
+        raise UndefinedEnvironmentName(
+            "{0!r} does not exist in evaluation environment.".format(name)
+        )
+
+    return value
+
+
+def _evaluate_markers(markers, environment):
+    groups = [[]]
+
+    for marker in markers:
+        assert isinstance(marker, (list, tuple, string_types))
+
+        if isinstance(marker, list):
+            groups[-1].append(_evaluate_markers(marker, environment))
+        elif isinstance(marker, tuple):
+            lhs, op, rhs = marker
+
+            if isinstance(lhs, Variable):
+                lhs_value = _get_env(environment, lhs.value)
+                rhs_value = rhs.value
+            else:
+                lhs_value = lhs.value
+                rhs_value = _get_env(environment, rhs.value)
+
+            groups[-1].append(_eval_op(lhs_value, op, rhs_value))
+        else:
+            assert marker in ["and", "or"]
+            if marker == "or":
+                groups.append([])
+
+    return any(all(item) for item in groups)
+
+
+def format_full_version(info):
+    version = "{0.major}.{0.minor}.{0.micro}".format(info)
+    kind = info.releaselevel
+    if kind != "final":
+        version += kind[0] + str(info.serial)
+    return version
+
+
+def default_environment():
+    if hasattr(sys, "implementation"):
+        iver = format_full_version(sys.implementation.version)
+        implementation_name = sys.implementation.name
+    else:
+        iver = "0"
+        implementation_name = ""
+
+    return {
+        "implementation_name": implementation_name,
+        "implementation_version": iver,
+        "os_name": os.name,
+        "platform_machine": platform.machine(),
+        "platform_release": platform.release(),
+        "platform_system": platform.system(),
+        "platform_version": platform.version(),
+        "python_full_version": platform.python_version(),
+        "platform_python_implementation": platform.python_implementation(),
+        "python_version": ".".join(platform.python_version_tuple()[:2]),
+        "sys_platform": sys.platform,
+    }
+
+
+class Marker(object):
+    def __init__(self, marker):
+        try:
+            self._markers = _coerce_parse_result(MARKER.parseString(marker))
+        except ParseException as e:
+            err_str = "Invalid marker: {0!r}, parse error at {1!r}".format(
+                marker, marker[e.loc : e.loc + 8]
+            )
+            raise InvalidMarker(err_str)
+
+    def __str__(self):
+        return _format_marker(self._markers)
+
+    def __repr__(self):
+        return "<Marker({0!r})>".format(str(self))
+
+    def evaluate(self, environment=None):
+        """Evaluate a marker.
+
+        Return the boolean from evaluating the given marker against the
+        environment. environment is an optional argument to override all or
+        part of the determined environment.
+
+        The environment is determined from the current Python process.
+        """
+        current_environment = default_environment()
+        if environment is not None:
+            current_environment.update(environment)
+
+        return _evaluate_markers(self._markers, current_environment)

venv/lib/python3.7/site-packages/pip/_vendor/packaging/requirements.py

@@ -0,0 +1,138 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import string
+import re
+
+from pip._vendor.pyparsing import stringStart, stringEnd, originalTextFor, ParseException
+from pip._vendor.pyparsing import ZeroOrMore, Word, Optional, Regex, Combine
+from pip._vendor.pyparsing import Literal as L  # noqa
+from pip._vendor.six.moves.urllib import parse as urlparse
+
+from .markers import MARKER_EXPR, Marker
+from .specifiers import LegacySpecifier, Specifier, SpecifierSet
+
+
+class InvalidRequirement(ValueError):
+    """
+    An invalid requirement was found, users should refer to PEP 508.
+    """
+
+
+ALPHANUM = Word(string.ascii_letters + string.digits)
+
+LBRACKET = L("[").suppress()
+RBRACKET = L("]").suppress()
+LPAREN = L("(").suppress()
+RPAREN = L(")").suppress()
+COMMA = L(",").suppress()
+SEMICOLON = L(";").suppress()
+AT = L("@").suppress()
+
+PUNCTUATION = Word("-_.")
+IDENTIFIER_END = ALPHANUM | (ZeroOrMore(PUNCTUATION) + ALPHANUM)
+IDENTIFIER = Combine(ALPHANUM + ZeroOrMore(IDENTIFIER_END))
+
+NAME = IDENTIFIER("name")
+EXTRA = IDENTIFIER
+
+URI = Regex(r"[^ ]+")("url")
+URL = AT + URI
+
+EXTRAS_LIST = EXTRA + ZeroOrMore(COMMA + EXTRA)
+EXTRAS = (LBRACKET + Optional(EXTRAS_LIST) + RBRACKET)("extras")
+
+VERSION_PEP440 = Regex(Specifier._regex_str, re.VERBOSE | re.IGNORECASE)
+VERSION_LEGACY = Regex(LegacySpecifier._regex_str, re.VERBOSE | re.IGNORECASE)
+
+VERSION_ONE = VERSION_PEP440 ^ VERSION_LEGACY
+VERSION_MANY = Combine(
+    VERSION_ONE + ZeroOrMore(COMMA + VERSION_ONE), joinString=",", adjacent=False
+)("_raw_spec")
+_VERSION_SPEC = Optional(((LPAREN + VERSION_MANY + RPAREN) | VERSION_MANY))
+_VERSION_SPEC.setParseAction(lambda s, l, t: t._raw_spec or "")
+
+VERSION_SPEC = originalTextFor(_VERSION_SPEC)("specifier")
+VERSION_SPEC.setParseAction(lambda s, l, t: t[1])
+
+MARKER_EXPR = originalTextFor(MARKER_EXPR())("marker")
+MARKER_EXPR.setParseAction(
+    lambda s, l, t: Marker(s[t._original_start : t._original_end])
+)
+MARKER_SEPARATOR = SEMICOLON
+MARKER = MARKER_SEPARATOR + MARKER_EXPR
+
+VERSION_AND_MARKER = VERSION_SPEC + Optional(MARKER)
+URL_AND_MARKER = URL + Optional(MARKER)
+
+NAMED_REQUIREMENT = NAME + Optional(EXTRAS) + (URL_AND_MARKER | VERSION_AND_MARKER)
+
+REQUIREMENT = stringStart + NAMED_REQUIREMENT + stringEnd
+# pyparsing isn't thread safe during initialization, so we do it eagerly, see
+# issue #104
+REQUIREMENT.parseString("x[]")
+
+
+class Requirement(object):
+    """Parse a requirement.
+
+    Parse a given requirement string into its parts, such as name, specifier,
+    URL, and extras. Raises InvalidRequirement on a badly-formed requirement
+    string.
+    """
+
+    # TODO: Can we test whether something is contained within a requirement?
+    #       If so how do we do that? Do we need to test against the _name_ of
+    #       the thing as well as the version? What about the markers?
+    # TODO: Can we normalize the name and extra name?
+
+    def __init__(self, requirement_string):
+        try:
+            req = REQUIREMENT.parseString(requirement_string)
+        except ParseException as e:
+            raise InvalidRequirement(
+                'Parse error at "{0!r}": {1}'.format(
+                    requirement_string[e.loc : e.loc + 8], e.msg
+                )
+            )
+
+        self.name = req.name
+        if req.url:
+            parsed_url = urlparse.urlparse(req.url)
+            if parsed_url.scheme == "file":
+                if urlparse.urlunparse(parsed_url) != req.url:
+                    raise InvalidRequirement("Invalid URL given")
+            elif not (parsed_url.scheme and parsed_url.netloc) or (
+                not parsed_url.scheme and not parsed_url.netloc
+            ):
+                raise InvalidRequirement("Invalid URL: {0}".format(req.url))
+            self.url = req.url
+        else:
+            self.url = None
+        self.extras = set(req.extras.asList() if req.extras else [])
+        self.specifier = SpecifierSet(req.specifier)
+        self.marker = req.marker if req.marker else None
+
+    def __str__(self):
+        parts = [self.name]
+
+        if self.extras:
+            parts.append("[{0}]".format(",".join(sorted(self.extras))))
+
+        if self.specifier:
+            parts.append(str(self.specifier))
+
+        if self.url:
+            parts.append("@ {0}".format(self.url))
+            if self.marker:
+                parts.append(" ")
+
+        if self.marker:
+            parts.append("; {0}".format(self.marker))
+
+        return "".join(parts)
+
+    def __repr__(self):
+        return "<Requirement({0!r})>".format(str(self))

venv/lib/python3.7/site-packages/pip/_vendor/packaging/specifiers.py

@@ -0,0 +1,749 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import abc
+import functools
+import itertools
+import re
+
+from ._compat import string_types, with_metaclass
+from .version import Version, LegacyVersion, parse
+
+
+class InvalidSpecifier(ValueError):
+    """
+    An invalid specifier was found, users should refer to PEP 440.
+    """
+
+
+class BaseSpecifier(with_metaclass(abc.ABCMeta, object)):
+    @abc.abstractmethod
+    def __str__(self):
+        """
+        Returns the str representation of this Specifier like object. This
+        should be representative of the Specifier itself.
+        """
+
+    @abc.abstractmethod
+    def __hash__(self):
+        """
+        Returns a hash value for this Specifier like object.
+        """
+
+    @abc.abstractmethod
+    def __eq__(self, other):
+        """
+        Returns a boolean representing whether or not the two Specifier like
+        objects are equal.
+        """
+
+    @abc.abstractmethod
+    def __ne__(self, other):
+        """
+        Returns a boolean representing whether or not the two Specifier like
+        objects are not equal.
+        """
+
+    @abc.abstractproperty
+    def prereleases(self):
+        """
+        Returns whether or not pre-releases as a whole are allowed by this
+        specifier.
+        """
+
+    @prereleases.setter
+    def prereleases(self, value):
+        """
+        Sets whether or not pre-releases as a whole are allowed by this
+        specifier.
+        """
+
+    @abc.abstractmethod
+    def contains(self, item, prereleases=None):
+        """
+        Determines if the given item is contained within this specifier.
+        """
+
+    @abc.abstractmethod
+    def filter(self, iterable, prereleases=None):
+        """
+        Takes an iterable of items and filters them so that only items which
+        are contained within this specifier are allowed in it.
+        """
+
+
+class _IndividualSpecifier(BaseSpecifier):
+
+    _operators = {}
+
+    def __init__(self, spec="", prereleases=None):
+        match = self._regex.search(spec)
+        if not match:
+            raise InvalidSpecifier("Invalid specifier: '{0}'".format(spec))
+
+        self._spec = (match.group("operator").strip(), match.group("version").strip())
+
+        # Store whether or not this Specifier should accept prereleases
+        self._prereleases = prereleases
+
+    def __repr__(self):
+        pre = (
+            ", prereleases={0!r}".format(self.prereleases)
+            if self._prereleases is not None
+            else ""
+        )
+
+        return "<{0}({1!r}{2})>".format(self.__class__.__name__, str(self), pre)
+
+    def __str__(self):
+        return "{0}{1}".format(*self._spec)
+
+    def __hash__(self):
+        return hash(self._spec)
+
+    def __eq__(self, other):
+        if isinstance(other, string_types):
+            try:
+                other = self.__class__(other)
+            except InvalidSpecifier:
+                return NotImplemented
+        elif not isinstance(other, self.__class__):
+            return NotImplemented
+
+        return self._spec == other._spec
+
+    def __ne__(self, other):
+        if isinstance(other, string_types):
+            try:
+                other = self.__class__(other)
+            except InvalidSpecifier:
+                return NotImplemented
+        elif not isinstance(other, self.__class__):
+            return NotImplemented
+
+        return self._spec != other._spec
+
+    def _get_operator(self, op):
+        return getattr(self, "_compare_{0}".format(self._operators[op]))
+
+    def _coerce_version(self, version):
+        if not isinstance(version, (LegacyVersion, Version)):
+            version = parse(version)
+        return version
+
+    @property
+    def operator(self):
+        return self._spec[0]
+
+    @property
+    def version(self):
+        return self._spec[1]
+
+    @property
+    def prereleases(self):
+        return self._prereleases
+
+    @prereleases.setter
+    def prereleases(self, value):
+        self._prereleases = value
+
+    def __contains__(self, item):
+        return self.contains(item)
+
+    def contains(self, item, prereleases=None):
+        # Determine if prereleases are to be allowed or not.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # Normalize item to a Version or LegacyVersion, this allows us to have
+        # a shortcut for ``"2.0" in Specifier(">=2")
+        item = self._coerce_version(item)
+
+        # Determine if we should be supporting prereleases in this specifier
+        # or not, if we do not support prereleases than we can short circuit
+        # logic if this version is a prereleases.
+        if item.is_prerelease and not prereleases:
+            return False
+
+        # Actually do the comparison to determine if this item is contained
+        # within this Specifier or not.
+        return self._get_operator(self.operator)(item, self.version)
+
+    def filter(self, iterable, prereleases=None):
+        yielded = False
+        found_prereleases = []
+
+        kw = {"prereleases": prereleases if prereleases is not None else True}
+
+        # Attempt to iterate over all the values in the iterable and if any of
+        # them match, yield them.
+        for version in iterable:
+            parsed_version = self._coerce_version(version)
+
+            if self.contains(parsed_version, **kw):
+                # If our version is a prerelease, and we were not set to allow
+                # prereleases, then we'll store it for later incase nothing
+                # else matches this specifier.
+                if parsed_version.is_prerelease and not (
+                    prereleases or self.prereleases
+                ):
+                    found_prereleases.append(version)
+                # Either this is not a prerelease, or we should have been
+                # accepting prereleases from the beginning.
+                else:
+                    yielded = True
+                    yield version
+
+        # Now that we've iterated over everything, determine if we've yielded
+        # any values, and if we have not and we have any prereleases stored up
+        # then we will go ahead and yield the prereleases.
+        if not yielded and found_prereleases:
+            for version in found_prereleases:
+                yield version
+
+
+class LegacySpecifier(_IndividualSpecifier):
+
+    _regex_str = r"""
+        (?P<operator>(==|!=|<=|>=|<|>))
+        \s*
+        (?P<version>
+            [^,;\s)]* # Since this is a "legacy" specifier, and the version
+                      # string can be just about anything, we match everything
+                      # except for whitespace, a semi-colon for marker support,
+                      # a closing paren since versions can be enclosed in
+                      # them, and a comma since it's a version separator.
+        )
+        """
+
+    _regex = re.compile(r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+
+    _operators = {
+        "==": "equal",
+        "!=": "not_equal",
+        "<=": "less_than_equal",
+        ">=": "greater_than_equal",
+        "<": "less_than",
+        ">": "greater_than",
+    }
+
+    def _coerce_version(self, version):
+        if not isinstance(version, LegacyVersion):
+            version = LegacyVersion(str(version))
+        return version
+
+    def _compare_equal(self, prospective, spec):
+        return prospective == self._coerce_version(spec)
+
+    def _compare_not_equal(self, prospective, spec):
+        return prospective != self._coerce_version(spec)
+
+    def _compare_less_than_equal(self, prospective, spec):
+        return prospective <= self._coerce_version(spec)
+
+    def _compare_greater_than_equal(self, prospective, spec):
+        return prospective >= self._coerce_version(spec)
+
+    def _compare_less_than(self, prospective, spec):
+        return prospective < self._coerce_version(spec)
+
+    def _compare_greater_than(self, prospective, spec):
+        return prospective > self._coerce_version(spec)
+
+
+def _require_version_compare(fn):
+    @functools.wraps(fn)
+    def wrapped(self, prospective, spec):
+        if not isinstance(prospective, Version):
+            return False
+        return fn(self, prospective, spec)
+
+    return wrapped
+
+
+class Specifier(_IndividualSpecifier):
+
+    _regex_str = r"""
+        (?P<operator>(~=|==|!=|<=|>=|<|>|===))
+        (?P<version>
+            (?:
+                # The identity operators allow for an escape hatch that will
+                # do an exact string match of the version you wish to install.
+                # This will not be parsed by PEP 440 and we cannot determine
+                # any semantic meaning from it. This operator is discouraged
+                # but included entirely as an escape hatch.
+                (?<====)  # Only match for the identity operator
+                \s*
+                [^\s]*    # We just match everything, except for whitespace
+                          # since we are only testing for strict identity.
+            )
+            |
+            (?:
+                # The (non)equality operators allow for wild card and local
+                # versions to be specified so we have to define these two
+                # operators separately to enable that.
+                (?<===|!=)            # Only match for equals and not equals
+
+                \s*
+                v?
+                (?:[0-9]+!)?          # epoch
+                [0-9]+(?:\.[0-9]+)*   # release
+                (?:                   # pre release
+                    [-_\.]?
+                    (a|b|c|rc|alpha|beta|pre|preview)
+                    [-_\.]?
+                    [0-9]*
+                )?
+                (?:                   # post release
+                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                )?
+
+                # You cannot use a wild card and a dev or local version
+                # together so group them with a | and make them optional.
+                (?:
+                    (?:[-_\.]?dev[-_\.]?[0-9]*)?         # dev release
+                    (?:\+[a-z0-9]+(?:[-_\.][a-z0-9]+)*)? # local
+                    |
+                    \.\*  # Wild card syntax of .*
+                )?
+            )
+            |
+            (?:
+                # The compatible operator requires at least two digits in the
+                # release segment.
+                (?<=~=)               # Only match for the compatible operator
+
+                \s*
+                v?
+                (?:[0-9]+!)?          # epoch
+                [0-9]+(?:\.[0-9]+)+   # release  (We have a + instead of a *)
+                (?:                   # pre release
+                    [-_\.]?
+                    (a|b|c|rc|alpha|beta|pre|preview)
+                    [-_\.]?
+                    [0-9]*
+                )?
+                (?:                                   # post release
+                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                )?
+                (?:[-_\.]?dev[-_\.]?[0-9]*)?          # dev release
+            )
+            |
+            (?:
+                # All other operators only allow a sub set of what the
+                # (non)equality operators do. Specifically they do not allow
+                # local versions to be specified nor do they allow the prefix
+                # matching wild cards.
+                (?<!==|!=|~=)         # We have special cases for these
+                                      # operators so we want to make sure they
+                                      # don't match here.
+
+                \s*
+                v?
+                (?:[0-9]+!)?          # epoch
+                [0-9]+(?:\.[0-9]+)*   # release
+                (?:                   # pre release
+                    [-_\.]?
+                    (a|b|c|rc|alpha|beta|pre|preview)
+                    [-_\.]?
+                    [0-9]*
+                )?
+                (?:                                   # post release
+                    (?:-[0-9]+)|(?:[-_\.]?(post|rev|r)[-_\.]?[0-9]*)
+                )?
+                (?:[-_\.]?dev[-_\.]?[0-9]*)?          # dev release
+            )
+        )
+        """
+
+    _regex = re.compile(r"^\s*" + _regex_str + r"\s*$", re.VERBOSE | re.IGNORECASE)
+
+    _operators = {
+        "~=": "compatible",
+        "==": "equal",
+        "!=": "not_equal",
+        "<=": "less_than_equal",
+        ">=": "greater_than_equal",
+        "<": "less_than",
+        ">": "greater_than",
+        "===": "arbitrary",
+    }
+
+    @_require_version_compare
+    def _compare_compatible(self, prospective, spec):
+        # Compatible releases have an equivalent combination of >= and ==. That
+        # is that ~=2.2 is equivalent to >=2.2,==2.*. This allows us to
+        # implement this in terms of the other specifiers instead of
+        # implementing it ourselves. The only thing we need to do is construct
+        # the other specifiers.
+
+        # We want everything but the last item in the version, but we want to
+        # ignore post and dev releases and we want to treat the pre-release as
+        # it's own separate segment.
+        prefix = ".".join(
+            list(
+                itertools.takewhile(
+                    lambda x: (not x.startswith("post") and not x.startswith("dev")),
+                    _version_split(spec),
+                )
+            )[:-1]
+        )
+
+        # Add the prefix notation to the end of our string
+        prefix += ".*"
+
+        return self._get_operator(">=")(prospective, spec) and self._get_operator("==")(
+            prospective, prefix
+        )
+
+    @_require_version_compare
+    def _compare_equal(self, prospective, spec):
+        # We need special logic to handle prefix matching
+        if spec.endswith(".*"):
+            # In the case of prefix matching we want to ignore local segment.
+            prospective = Version(prospective.public)
+            # Split the spec out by dots, and pretend that there is an implicit
+            # dot in between a release segment and a pre-release segment.
+            spec = _version_split(spec[:-2])  # Remove the trailing .*
+
+            # Split the prospective version out by dots, and pretend that there
+            # is an implicit dot in between a release segment and a pre-release
+            # segment.
+            prospective = _version_split(str(prospective))
+
+            # Shorten the prospective version to be the same length as the spec
+            # so that we can determine if the specifier is a prefix of the
+            # prospective version or not.
+            prospective = prospective[: len(spec)]
+
+            # Pad out our two sides with zeros so that they both equal the same
+            # length.
+            spec, prospective = _pad_version(spec, prospective)
+        else:
+            # Convert our spec string into a Version
+            spec = Version(spec)
+
+            # If the specifier does not have a local segment, then we want to
+            # act as if the prospective version also does not have a local
+            # segment.
+            if not spec.local:
+                prospective = Version(prospective.public)
+
+        return prospective == spec
+
+    @_require_version_compare
+    def _compare_not_equal(self, prospective, spec):
+        return not self._compare_equal(prospective, spec)
+
+    @_require_version_compare
+    def _compare_less_than_equal(self, prospective, spec):
+        return prospective <= Version(spec)
+
+    @_require_version_compare
+    def _compare_greater_than_equal(self, prospective, spec):
+        return prospective >= Version(spec)
+
+    @_require_version_compare
+    def _compare_less_than(self, prospective, spec):
+        # Convert our spec to a Version instance, since we'll want to work with
+        # it as a version.
+        spec = Version(spec)
+
+        # Check to see if the prospective version is less than the spec
+        # version. If it's not we can short circuit and just return False now
+        # instead of doing extra unneeded work.
+        if not prospective < spec:
+            return False
+
+        # This special case is here so that, unless the specifier itself
+        # includes is a pre-release version, that we do not accept pre-release
+        # versions for the version mentioned in the specifier (e.g. <3.1 should
+        # not match 3.1.dev0, but should match 3.0.dev0).
+        if not spec.is_prerelease and prospective.is_prerelease:
+            if Version(prospective.base_version) == Version(spec.base_version):
+                return False
+
+        # If we've gotten to here, it means that prospective version is both
+        # less than the spec version *and* it's not a pre-release of the same
+        # version in the spec.
+        return True
+
+    @_require_version_compare
+    def _compare_greater_than(self, prospective, spec):
+        # Convert our spec to a Version instance, since we'll want to work with
+        # it as a version.
+        spec = Version(spec)
+
+        # Check to see if the prospective version is greater than the spec
+        # version. If it's not we can short circuit and just return False now
+        # instead of doing extra unneeded work.
+        if not prospective > spec:
+            return False
+
+        # This special case is here so that, unless the specifier itself
+        # includes is a post-release version, that we do not accept
+        # post-release versions for the version mentioned in the specifier
+        # (e.g. >3.1 should not match 3.0.post0, but should match 3.2.post0).
+        if not spec.is_postrelease and prospective.is_postrelease:
+            if Version(prospective.base_version) == Version(spec.base_version):
+                return False
+
+        # Ensure that we do not allow a local version of the version mentioned
+        # in the specifier, which is technically greater than, to match.
+        if prospective.local is not None:
+            if Version(prospective.base_version) == Version(spec.base_version):
+                return False
+
+        # If we've gotten to here, it means that prospective version is both
+        # greater than the spec version *and* it's not a pre-release of the
+        # same version in the spec.
+        return True
+
+    def _compare_arbitrary(self, prospective, spec):
+        return str(prospective).lower() == str(spec).lower()
+
+    @property
+    def prereleases(self):
+        # If there is an explicit prereleases set for this, then we'll just
+        # blindly use that.
+        if self._prereleases is not None:
+            return self._prereleases
+
+        # Look at all of our specifiers and determine if they are inclusive
+        # operators, and if they are if they are including an explicit
+        # prerelease.
+        operator, version = self._spec
+        if operator in ["==", ">=", "<=", "~=", "==="]:
+            # The == specifier can include a trailing .*, if it does we
+            # want to remove before parsing.
+            if operator == "==" and version.endswith(".*"):
+                version = version[:-2]
+
+            # Parse the version, and if it is a pre-release than this
+            # specifier allows pre-releases.
+            if parse(version).is_prerelease:
+                return True
+
+        return False
+
+    @prereleases.setter
+    def prereleases(self, value):
+        self._prereleases = value
+
+
+_prefix_regex = re.compile(r"^([0-9]+)((?:a|b|c|rc)[0-9]+)$")
+
+
+def _version_split(version):
+    result = []
+    for item in version.split("."):
+        match = _prefix_regex.search(item)
+        if match:
+            result.extend(match.groups())
+        else:
+            result.append(item)
+    return result
+
+
+def _pad_version(left, right):
+    left_split, right_split = [], []
+
+    # Get the release segment of our versions
+    left_split.append(list(itertools.takewhile(lambda x: x.isdigit(), left)))
+    right_split.append(list(itertools.takewhile(lambda x: x.isdigit(), right)))
+
+    # Get the rest of our versions
+    left_split.append(left[len(left_split[0]) :])
+    right_split.append(right[len(right_split[0]) :])
+
+    # Insert our padding
+    left_split.insert(1, ["0"] * max(0, len(right_split[0]) - len(left_split[0])))
+    right_split.insert(1, ["0"] * max(0, len(left_split[0]) - len(right_split[0])))
+
+    return (list(itertools.chain(*left_split)), list(itertools.chain(*right_split)))
+
+
+class SpecifierSet(BaseSpecifier):
+    def __init__(self, specifiers="", prereleases=None):
+        # Split on , to break each indidivual specifier into it's own item, and
+        # strip each item to remove leading/trailing whitespace.
+        specifiers = [s.strip() for s in specifiers.split(",") if s.strip()]
+
+        # Parsed each individual specifier, attempting first to make it a
+        # Specifier and falling back to a LegacySpecifier.
+        parsed = set()
+        for specifier in specifiers:
+            try:
+                parsed.add(Specifier(specifier))
+            except InvalidSpecifier:
+                parsed.add(LegacySpecifier(specifier))
+
+        # Turn our parsed specifiers into a frozen set and save them for later.
+        self._specs = frozenset(parsed)
+
+        # Store our prereleases value so we can use it later to determine if
+        # we accept prereleases or not.
+        self._prereleases = prereleases
+
+    def __repr__(self):
+        pre = (
+            ", prereleases={0!r}".format(self.prereleases)
+            if self._prereleases is not None
+            else ""
+        )
+
+        return "<SpecifierSet({0!r}{1})>".format(str(self), pre)
+
+    def __str__(self):
+        return ",".join(sorted(str(s) for s in self._specs))
+
+    def __hash__(self):
+        return hash(self._specs)
+
+    def __and__(self, other):
+        if isinstance(other, string_types):
+            other = SpecifierSet(other)
+        elif not isinstance(other, SpecifierSet):
+            return NotImplemented
+
+        specifier = SpecifierSet()
+        specifier._specs = frozenset(self._specs | other._specs)
+
+        if self._prereleases is None and other._prereleases is not None:
+            specifier._prereleases = other._prereleases
+        elif self._prereleases is not None and other._prereleases is None:
+            specifier._prereleases = self._prereleases
+        elif self._prereleases == other._prereleases:
+            specifier._prereleases = self._prereleases
+        else:
+            raise ValueError(
+                "Cannot combine SpecifierSets with True and False prerelease "
+                "overrides."
+            )
+
+        return specifier
+
+    def __eq__(self, other):
+        if isinstance(other, string_types):
+            other = SpecifierSet(other)
+        elif isinstance(other, _IndividualSpecifier):
+            other = SpecifierSet(str(other))
+        elif not isinstance(other, SpecifierSet):
+            return NotImplemented
+
+        return self._specs == other._specs
+
+    def __ne__(self, other):
+        if isinstance(other, string_types):
+            other = SpecifierSet(other)
+        elif isinstance(other, _IndividualSpecifier):
+            other = SpecifierSet(str(other))
+        elif not isinstance(other, SpecifierSet):
+            return NotImplemented
+
+        return self._specs != other._specs
+
+    def __len__(self):
+        return len(self._specs)
+
+    def __iter__(self):
+        return iter(self._specs)
+
+    @property
+    def prereleases(self):
+        # If we have been given an explicit prerelease modifier, then we'll
+        # pass that through here.
+        if self._prereleases is not None:
+            return self._prereleases
+
+        # If we don't have any specifiers, and we don't have a forced value,
+        # then we'll just return None since we don't know if this should have
+        # pre-releases or not.
+        if not self._specs:
+            return None
+
+        # Otherwise we'll see if any of the given specifiers accept
+        # prereleases, if any of them do we'll return True, otherwise False.
+        return any(s.prereleases for s in self._specs)
+
+    @prereleases.setter
+    def prereleases(self, value):
+        self._prereleases = value
+
+    def __contains__(self, item):
+        return self.contains(item)
+
+    def contains(self, item, prereleases=None):
+        # Ensure that our item is a Version or LegacyVersion instance.
+        if not isinstance(item, (LegacyVersion, Version)):
+            item = parse(item)
+
+        # Determine if we're forcing a prerelease or not, if we're not forcing
+        # one for this particular filter call, then we'll use whatever the
+        # SpecifierSet thinks for whether or not we should support prereleases.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # We can determine if we're going to allow pre-releases by looking to
+        # see if any of the underlying items supports them. If none of them do
+        # and this item is a pre-release then we do not allow it and we can
+        # short circuit that here.
+        # Note: This means that 1.0.dev1 would not be contained in something
+        #       like >=1.0.devabc however it would be in >=1.0.debabc,>0.0.dev0
+        if not prereleases and item.is_prerelease:
+            return False
+
+        # We simply dispatch to the underlying specs here to make sure that the
+        # given version is contained within all of them.
+        # Note: This use of all() here means that an empty set of specifiers
+        #       will always return True, this is an explicit design decision.
+        return all(s.contains(item, prereleases=prereleases) for s in self._specs)
+
+    def filter(self, iterable, prereleases=None):
+        # Determine if we're forcing a prerelease or not, if we're not forcing
+        # one for this particular filter call, then we'll use whatever the
+        # SpecifierSet thinks for whether or not we should support prereleases.
+        if prereleases is None:
+            prereleases = self.prereleases
+
+        # If we have any specifiers, then we want to wrap our iterable in the
+        # filter method for each one, this will act as a logical AND amongst
+        # each specifier.
+        if self._specs:
+            for spec in self._specs:
+                iterable = spec.filter(iterable, prereleases=bool(prereleases))
+            return iterable
+        # If we do not have any specifiers, then we need to have a rough filter
+        # which will filter out any pre-releases, unless there are no final
+        # releases, and which will filter out LegacyVersion in general.
+        else:
+            filtered = []
+            found_prereleases = []
+
+            for item in iterable:
+                # Ensure that we some kind of Version class for this item.
+                if not isinstance(item, (LegacyVersion, Version)):
+                    parsed_version = parse(item)
+                else:
+                    parsed_version = item
+
+                # Filter out any item which is parsed as a LegacyVersion
+                if isinstance(parsed_version, LegacyVersion):
+                    continue
+
+                # Store any item which is a pre-release for later unless we've
+                # already found a final version or we are accepting prereleases
+                if parsed_version.is_prerelease and not prereleases:
+                    if not filtered:
+                        found_prereleases.append(item)
+                else:
+                    filtered.append(item)
+
+            # If we've found no items except for pre-releases, then we'll go
+            # ahead and use the pre-releases
+            if not filtered and found_prereleases and prereleases is None:
+                return found_prereleases
+
+            return filtered

venv/lib/python3.7/site-packages/pip/_vendor/packaging/tags.py

@@ -0,0 +1,404 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+from __future__ import absolute_import
+
+import distutils.util
+
+try:
+    from importlib.machinery import EXTENSION_SUFFIXES
+except ImportError:  # pragma: no cover
+    import imp
+
+    EXTENSION_SUFFIXES = [x[0] for x in imp.get_suffixes()]
+    del imp
+import platform
+import re
+import sys
+import sysconfig
+import warnings
+
+
+INTERPRETER_SHORT_NAMES = {
+    "python": "py",  # Generic.
+    "cpython": "cp",
+    "pypy": "pp",
+    "ironpython": "ip",
+    "jython": "jy",
+}
+
+
+_32_BIT_INTERPRETER = sys.maxsize <= 2 ** 32
+
+
+class Tag(object):
+
+    __slots__ = ["_interpreter", "_abi", "_platform"]
+
+    def __init__(self, interpreter, abi, platform):
+        self._interpreter = interpreter.lower()
+        self._abi = abi.lower()
+        self._platform = platform.lower()
+
+    @property
+    def interpreter(self):
+        return self._interpreter
+
+    @property
+    def abi(self):
+        return self._abi
+
+    @property
+    def platform(self):
+        return self._platform
+
+    def __eq__(self, other):
+        return (
+            (self.platform == other.platform)
+            and (self.abi == other.abi)
+            and (self.interpreter == other.interpreter)
+        )
+
+    def __hash__(self):
+        return hash((self._interpreter, self._abi, self._platform))
+
+    def __str__(self):
+        return "{}-{}-{}".format(self._interpreter, self._abi, self._platform)
+
+    def __repr__(self):
+        return "<{self} @ {self_id}>".format(self=self, self_id=id(self))
+
+
+def parse_tag(tag):
+    tags = set()
+    interpreters, abis, platforms = tag.split("-")
+    for interpreter in interpreters.split("."):
+        for abi in abis.split("."):
+            for platform_ in platforms.split("."):
+                tags.add(Tag(interpreter, abi, platform_))
+    return frozenset(tags)
+
+
+def _normalize_string(string):
+    return string.replace(".", "_").replace("-", "_")
+
+
+def _cpython_interpreter(py_version):
+    # TODO: Is using py_version_nodot for interpreter version critical?
+    return "cp{major}{minor}".format(major=py_version[0], minor=py_version[1])
+
+
+def _cpython_abis(py_version):
+    abis = []
+    version = "{}{}".format(*py_version[:2])
+    debug = pymalloc = ucs4 = ""
+    with_debug = sysconfig.get_config_var("Py_DEBUG")
+    has_refcount = hasattr(sys, "gettotalrefcount")
+    # Windows doesn't set Py_DEBUG, so checking for support of debug-compiled
+    # extension modules is the best option.
+    # https://github.com/pypa/pip/issues/3383#issuecomment-173267692
+    has_ext = "_d.pyd" in EXTENSION_SUFFIXES
+    if with_debug or (with_debug is None and (has_refcount or has_ext)):
+        debug = "d"
+    if py_version < (3, 8):
+        with_pymalloc = sysconfig.get_config_var("WITH_PYMALLOC")
+        if with_pymalloc or with_pymalloc is None:
+            pymalloc = "m"
+        if py_version < (3, 3):
+            unicode_size = sysconfig.get_config_var("Py_UNICODE_SIZE")
+            if unicode_size == 4 or (
+                unicode_size is None and sys.maxunicode == 0x10FFFF
+            ):
+                ucs4 = "u"
+    elif debug:
+        # Debug builds can also load "normal" extension modules.
+        # We can also assume no UCS-4 or pymalloc requirement.
+        abis.append("cp{version}".format(version=version))
+    abis.insert(
+        0,
+        "cp{version}{debug}{pymalloc}{ucs4}".format(
+            version=version, debug=debug, pymalloc=pymalloc, ucs4=ucs4
+        ),
+    )
+    return abis
+
+
+def _cpython_tags(py_version, interpreter, abis, platforms):
+    for abi in abis:
+        for platform_ in platforms:
+            yield Tag(interpreter, abi, platform_)
+    for tag in (Tag(interpreter, "abi3", platform_) for platform_ in platforms):
+        yield tag
+    for tag in (Tag(interpreter, "none", platform_) for platform_ in platforms):
+        yield tag
+    # PEP 384 was first implemented in Python 3.2.
+    for minor_version in range(py_version[1] - 1, 1, -1):
+        for platform_ in platforms:
+            interpreter = "cp{major}{minor}".format(
+                major=py_version[0], minor=minor_version
+            )
+            yield Tag(interpreter, "abi3", platform_)
+
+
+def _pypy_interpreter():
+    return "pp{py_major}{pypy_major}{pypy_minor}".format(
+        py_major=sys.version_info[0],
+        pypy_major=sys.pypy_version_info.major,
+        pypy_minor=sys.pypy_version_info.minor,
+    )
+
+
+def _generic_abi():
+    abi = sysconfig.get_config_var("SOABI")
+    if abi:
+        return _normalize_string(abi)
+    else:
+        return "none"
+
+
+def _pypy_tags(py_version, interpreter, abi, platforms):
+    for tag in (Tag(interpreter, abi, platform) for platform in platforms):
+        yield tag
+    for tag in (Tag(interpreter, "none", platform) for platform in platforms):
+        yield tag
+
+
+def _generic_tags(interpreter, py_version, abi, platforms):
+    for tag in (Tag(interpreter, abi, platform) for platform in platforms):
+        yield tag
+    if abi != "none":
+        tags = (Tag(interpreter, "none", platform_) for platform_ in platforms)
+        for tag in tags:
+            yield tag
+
+
+def _py_interpreter_range(py_version):
+    """
+    Yield Python versions in descending order.
+
+    After the latest version, the major-only version will be yielded, and then
+    all following versions up to 'end'.
+    """
+    yield "py{major}{minor}".format(major=py_version[0], minor=py_version[1])
+    yield "py{major}".format(major=py_version[0])
+    for minor in range(py_version[1] - 1, -1, -1):
+        yield "py{major}{minor}".format(major=py_version[0], minor=minor)
+
+
+def _independent_tags(interpreter, py_version, platforms):
+    """
+    Return the sequence of tags that are consistent across implementations.
+
+    The tags consist of:
+    - py*-none-<platform>
+    - <interpreter>-none-any
+    - py*-none-any
+    """
+    for version in _py_interpreter_range(py_version):
+        for platform_ in platforms:
+            yield Tag(version, "none", platform_)
+    yield Tag(interpreter, "none", "any")
+    for version in _py_interpreter_range(py_version):
+        yield Tag(version, "none", "any")
+
+
+def _mac_arch(arch, is_32bit=_32_BIT_INTERPRETER):
+    if not is_32bit:
+        return arch
+
+    if arch.startswith("ppc"):
+        return "ppc"
+
+    return "i386"
+
+
+def _mac_binary_formats(version, cpu_arch):
+    formats = [cpu_arch]
+    if cpu_arch == "x86_64":
+        if version < (10, 4):
+            return []
+        formats.extend(["intel", "fat64", "fat32"])
+
+    elif cpu_arch == "i386":
+        if version < (10, 4):
+            return []
+        formats.extend(["intel", "fat32", "fat"])
+
+    elif cpu_arch == "ppc64":
+        # TODO: Need to care about 32-bit PPC for ppc64 through 10.2?
+        if version > (10, 5) or version < (10, 4):
+            return []
+        formats.append("fat64")
+
+    elif cpu_arch == "ppc":
+        if version > (10, 6):
+            return []
+        formats.extend(["fat32", "fat"])
+
+    formats.append("universal")
+    return formats
+
+
+def _mac_platforms(version=None, arch=None):
+    version_str, _, cpu_arch = platform.mac_ver()
+    if version is None:
+        version = tuple(map(int, version_str.split(".")[:2]))
+    if arch is None:
+        arch = _mac_arch(cpu_arch)
+    platforms = []
+    for minor_version in range(version[1], -1, -1):
+        compat_version = version[0], minor_version
+        binary_formats = _mac_binary_formats(compat_version, arch)
+        for binary_format in binary_formats:
+            platforms.append(
+                "macosx_{major}_{minor}_{binary_format}".format(
+                    major=compat_version[0],
+                    minor=compat_version[1],
+                    binary_format=binary_format,
+                )
+            )
+    return platforms
+
+
+# From PEP 513.
+def _is_manylinux_compatible(name, glibc_version):
+    # Check for presence of _manylinux module.
+    try:
+        import _manylinux
+
+        return bool(getattr(_manylinux, name + "_compatible"))
+    except (ImportError, AttributeError):
+        # Fall through to heuristic check below.
+        pass
+
+    return _have_compatible_glibc(*glibc_version)
+
+
+def _glibc_version_string():
+    # Returns glibc version string, or None if not using glibc.
+    import ctypes
+
+    # ctypes.CDLL(None) internally calls dlopen(NULL), and as the dlopen
+    # manpage says, "If filename is NULL, then the returned handle is for the
+    # main program". This way we can let the linker do the work to figure out
+    # which libc our process is actually using.
+    process_namespace = ctypes.CDLL(None)
+    try:
+        gnu_get_libc_version = process_namespace.gnu_get_libc_version
+    except AttributeError:
+        # Symbol doesn't exist -> therefore, we are not linked to
+        # glibc.
+        return None
+
+    # Call gnu_get_libc_version, which returns a string like "2.5"
+    gnu_get_libc_version.restype = ctypes.c_char_p
+    version_str = gnu_get_libc_version()
+    # py2 / py3 compatibility:
+    if not isinstance(version_str, str):
+        version_str = version_str.decode("ascii")
+
+    return version_str
+
+
+# Separated out from have_compatible_glibc for easier unit testing.
+def _check_glibc_version(version_str, required_major, minimum_minor):
+    # Parse string and check against requested version.
+    #
+    # We use a regexp instead of str.split because we want to discard any
+    # random junk that might come after the minor version -- this might happen
+    # in patched/forked versions of glibc (e.g. Linaro's version of glibc
+    # uses version strings like "2.20-2014.11"). See gh-3588.
+    m = re.match(r"(?P<major>[0-9]+)\.(?P<minor>[0-9]+)", version_str)
+    if not m:
+        warnings.warn(
+            "Expected glibc version with 2 components major.minor,"
+            " got: %s" % version_str,
+            RuntimeWarning,
+        )
+        return False
+    return (
+        int(m.group("major")) == required_major
+        and int(m.group("minor")) >= minimum_minor
+    )
+
+
+def _have_compatible_glibc(required_major, minimum_minor):
+    version_str = _glibc_version_string()
+    if version_str is None:
+        return False
+    return _check_glibc_version(version_str, required_major, minimum_minor)
+
+
+def _linux_platforms(is_32bit=_32_BIT_INTERPRETER):
+    linux = _normalize_string(distutils.util.get_platform())
+    if linux == "linux_x86_64" and is_32bit:
+        linux = "linux_i686"
+    manylinux_support = (
+        ("manylinux2014", (2, 17)),  # CentOS 7 w/ glibc 2.17 (PEP 599)
+        ("manylinux2010", (2, 12)),  # CentOS 6 w/ glibc 2.12 (PEP 571)
+        ("manylinux1", (2, 5)),  # CentOS 5 w/ glibc 2.5 (PEP 513)
+    )
+    manylinux_support_iter = iter(manylinux_support)
+    for name, glibc_version in manylinux_support_iter:
+        if _is_manylinux_compatible(name, glibc_version):
+            platforms = [linux.replace("linux", name)]
+            break
+    else:
+        platforms = []
+    # Support for a later manylinux implies support for an earlier version.
+    platforms += [linux.replace("linux", name) for name, _ in manylinux_support_iter]
+    platforms.append(linux)
+    return platforms
+
+
+def _generic_platforms():
+    platform = _normalize_string(distutils.util.get_platform())
+    return [platform]
+
+
+def _interpreter_name():
+    name = platform.python_implementation().lower()
+    return INTERPRETER_SHORT_NAMES.get(name) or name
+
+
+def _generic_interpreter(name, py_version):
+    version = sysconfig.get_config_var("py_version_nodot")
+    if not version:
+        version = "".join(map(str, py_version[:2]))
+    return "{name}{version}".format(name=name, version=version)
+
+
+def sys_tags():
+    """
+    Returns the sequence of tag triples for the running interpreter.
+
+    The order of the sequence corresponds to priority order for the
+    interpreter, from most to least important.
+    """
+    py_version = sys.version_info[:2]
+    interpreter_name = _interpreter_name()
+    if platform.system() == "Darwin":
+        platforms = _mac_platforms()
+    elif platform.system() == "Linux":
+        platforms = _linux_platforms()
+    else:
+        platforms = _generic_platforms()
+
+    if interpreter_name == "cp":
+        interpreter = _cpython_interpreter(py_version)
+        abis = _cpython_abis(py_version)
+        for tag in _cpython_tags(py_version, interpreter, abis, platforms):
+            yield tag
+    elif interpreter_name == "pp":
+        interpreter = _pypy_interpreter()
+        abi = _generic_abi()
+        for tag in _pypy_tags(py_version, interpreter, abi, platforms):
+            yield tag
+    else:
+        interpreter = _generic_interpreter(interpreter_name, py_version)
+        abi = _generic_abi()
+        for tag in _generic_tags(interpreter, py_version, abi, platforms):
+            yield tag
+    for tag in _independent_tags(interpreter, py_version, platforms):
+        yield tag

venv/lib/python3.7/site-packages/pip/_vendor/packaging/utils.py

@@ -0,0 +1,57 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import re
+
+from .version import InvalidVersion, Version
+
+
+_canonicalize_regex = re.compile(r"[-_.]+")
+
+
+def canonicalize_name(name):
+    # This is taken from PEP 503.
+    return _canonicalize_regex.sub("-", name).lower()
+
+
+def canonicalize_version(version):
+    """
+    This is very similar to Version.__str__, but has one subtle differences
+    with the way it handles the release segment.
+    """
+
+    try:
+        version = Version(version)
+    except InvalidVersion:
+        # Legacy versions cannot be normalized
+        return version
+
+    parts = []
+
+    # Epoch
+    if version.epoch != 0:
+        parts.append("{0}!".format(version.epoch))
+
+    # Release segment
+    # NB: This strips trailing '.0's to normalize
+    parts.append(re.sub(r"(\.0)+$", "", ".".join(str(x) for x in version.release)))
+
+    # Pre-release
+    if version.pre is not None:
+        parts.append("".join(str(x) for x in version.pre))
+
+    # Post-release
+    if version.post is not None:
+        parts.append(".post{0}".format(version.post))
+
+    # Development release
+    if version.dev is not None:
+        parts.append(".dev{0}".format(version.dev))
+
+    # Local version segment
+    if version.local is not None:
+        parts.append("+{0}".format(version.local))
+
+    return "".join(parts)

venv/lib/python3.7/site-packages/pip/_vendor/packaging/version.py

@@ -0,0 +1,420 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import collections
+import itertools
+import re
+
+from ._structures import Infinity
+
+
+__all__ = ["parse", "Version", "LegacyVersion", "InvalidVersion", "VERSION_PATTERN"]
+
+
+_Version = collections.namedtuple(
+    "_Version", ["epoch", "release", "dev", "pre", "post", "local"]
+)
+
+
+def parse(version):
+    """
+    Parse the given version string and return either a :class:`Version` object
+    or a :class:`LegacyVersion` object depending on if the given version is
+    a valid PEP 440 version or a legacy version.
+    """
+    try:
+        return Version(version)
+    except InvalidVersion:
+        return LegacyVersion(version)
+
+
+class InvalidVersion(ValueError):
+    """
+    An invalid version was found, users should refer to PEP 440.
+    """
+
+
+class _BaseVersion(object):
+    def __hash__(self):
+        return hash(self._key)
+
+    def __lt__(self, other):
+        return self._compare(other, lambda s, o: s < o)
+
+    def __le__(self, other):
+        return self._compare(other, lambda s, o: s <= o)
+
+    def __eq__(self, other):
+        return self._compare(other, lambda s, o: s == o)
+
+    def __ge__(self, other):
+        return self._compare(other, lambda s, o: s >= o)
+
+    def __gt__(self, other):
+        return self._compare(other, lambda s, o: s > o)
+
+    def __ne__(self, other):
+        return self._compare(other, lambda s, o: s != o)
+
+    def _compare(self, other, method):
+        if not isinstance(other, _BaseVersion):
+            return NotImplemented
+
+        return method(self._key, other._key)
+
+
+class LegacyVersion(_BaseVersion):
+    def __init__(self, version):
+        self._version = str(version)
+        self._key = _legacy_cmpkey(self._version)
+
+    def __str__(self):
+        return self._version
+
+    def __repr__(self):
+        return "<LegacyVersion({0})>".format(repr(str(self)))
+
+    @property
+    def public(self):
+        return self._version
+
+    @property
+    def base_version(self):
+        return self._version
+
+    @property
+    def epoch(self):
+        return -1
+
+    @property
+    def release(self):
+        return None
+
+    @property
+    def pre(self):
+        return None
+
+    @property
+    def post(self):
+        return None
+
+    @property
+    def dev(self):
+        return None
+
+    @property
+    def local(self):
+        return None
+
+    @property
+    def is_prerelease(self):
+        return False
+
+    @property
+    def is_postrelease(self):
+        return False
+
+    @property
+    def is_devrelease(self):
+        return False
+
+
+_legacy_version_component_re = re.compile(r"(\d+ | [a-z]+ | \.| -)", re.VERBOSE)
+
+_legacy_version_replacement_map = {
+    "pre": "c",
+    "preview": "c",
+    "-": "final-",
+    "rc": "c",
+    "dev": "@",
+}
+
+
+def _parse_version_parts(s):
+    for part in _legacy_version_component_re.split(s):
+        part = _legacy_version_replacement_map.get(part, part)
+
+        if not part or part == ".":
+            continue
+
+        if part[:1] in "0123456789":
+            # pad for numeric comparison
+            yield part.zfill(8)
+        else:
+            yield "*" + part
+
+    # ensure that alpha/beta/candidate are before final
+    yield "*final"
+
+
+def _legacy_cmpkey(version):
+    # We hardcode an epoch of -1 here. A PEP 440 version can only have a epoch
+    # greater than or equal to 0. This will effectively put the LegacyVersion,
+    # which uses the defacto standard originally implemented by setuptools,
+    # as before all PEP 440 versions.
+    epoch = -1
+
+    # This scheme is taken from pkg_resources.parse_version setuptools prior to
+    # it's adoption of the packaging library.
+    parts = []
+    for part in _parse_version_parts(version.lower()):
+        if part.startswith("*"):
+            # remove "-" before a prerelease tag
+            if part < "*final":
+                while parts and parts[-1] == "*final-":
+                    parts.pop()
+
+            # remove trailing zeros from each series of numeric parts
+            while parts and parts[-1] == "00000000":
+                parts.pop()
+
+        parts.append(part)
+    parts = tuple(parts)
+
+    return epoch, parts
+
+
+# Deliberately not anchored to the start and end of the string, to make it
+# easier for 3rd party code to reuse
+VERSION_PATTERN = r"""
+    v?
+    (?:
+        (?:(?P<epoch>[0-9]+)!)?                           # epoch
+        (?P<release>[0-9]+(?:\.[0-9]+)*)                  # release segment
+        (?P<pre>                                          # pre-release
+            [-_\.]?
+            (?P<pre_l>(a|b|c|rc|alpha|beta|pre|preview))
+            [-_\.]?
+            (?P<pre_n>[0-9]+)?
+        )?
+        (?P<post>                                         # post release
+            (?:-(?P<post_n1>[0-9]+))
+            |
+            (?:
+                [-_\.]?
+                (?P<post_l>post|rev|r)
+                [-_\.]?
+                (?P<post_n2>[0-9]+)?
+            )
+        )?
+        (?P<dev>                                          # dev release
+            [-_\.]?
+            (?P<dev_l>dev)
+            [-_\.]?
+            (?P<dev_n>[0-9]+)?
+        )?
+    )
+    (?:\+(?P<local>[a-z0-9]+(?:[-_\.][a-z0-9]+)*))?       # local version
+"""
+
+
+class Version(_BaseVersion):
+
+    _regex = re.compile(r"^\s*" + VERSION_PATTERN + r"\s*$", re.VERBOSE | re.IGNORECASE)
+
+    def __init__(self, version):
+        # Validate the version and parse it into pieces
+        match = self._regex.search(version)
+        if not match:
+            raise InvalidVersion("Invalid version: '{0}'".format(version))
+
+        # Store the parsed out pieces of the version
+        self._version = _Version(
+            epoch=int(match.group("epoch")) if match.group("epoch") else 0,
+            release=tuple(int(i) for i in match.group("release").split(".")),
+            pre=_parse_letter_version(match.group("pre_l"), match.group("pre_n")),
+            post=_parse_letter_version(
+                match.group("post_l"), match.group("post_n1") or match.group("post_n2")
+            ),
+            dev=_parse_letter_version(match.group("dev_l"), match.group("dev_n")),
+            local=_parse_local_version(match.group("local")),
+        )
+
+        # Generate a key which will be used for sorting
+        self._key = _cmpkey(
+            self._version.epoch,
+            self._version.release,
+            self._version.pre,
+            self._version.post,
+            self._version.dev,
+            self._version.local,
+        )
+
+    def __repr__(self):
+        return "<Version({0})>".format(repr(str(self)))
+
+    def __str__(self):
+        parts = []
+
+        # Epoch
+        if self.epoch != 0:
+            parts.append("{0}!".format(self.epoch))
+
+        # Release segment
+        parts.append(".".join(str(x) for x in self.release))
+
+        # Pre-release
+        if self.pre is not None:
+            parts.append("".join(str(x) for x in self.pre))
+
+        # Post-release
+        if self.post is not None:
+            parts.append(".post{0}".format(self.post))
+
+        # Development release
+        if self.dev is not None:
+            parts.append(".dev{0}".format(self.dev))
+
+        # Local version segment
+        if self.local is not None:
+            parts.append("+{0}".format(self.local))
+
+        return "".join(parts)
+
+    @property
+    def epoch(self):
+        return self._version.epoch
+
+    @property
+    def release(self):
+        return self._version.release
+
+    @property
+    def pre(self):
+        return self._version.pre
+
+    @property
+    def post(self):
+        return self._version.post[1] if self._version.post else None
+
+    @property
+    def dev(self):
+        return self._version.dev[1] if self._version.dev else None
+
+    @property
+    def local(self):
+        if self._version.local:
+            return ".".join(str(x) for x in self._version.local)
+        else:
+            return None
+
+    @property
+    def public(self):
+        return str(self).split("+", 1)[0]
+
+    @property
+    def base_version(self):
+        parts = []
+
+        # Epoch
+        if self.epoch != 0:
+            parts.append("{0}!".format(self.epoch))
+
+        # Release segment
+        parts.append(".".join(str(x) for x in self.release))
+
+        return "".join(parts)
+
+    @property
+    def is_prerelease(self):
+        return self.dev is not None or self.pre is not None
+
+    @property
+    def is_postrelease(self):
+        return self.post is not None
+
+    @property
+    def is_devrelease(self):
+        return self.dev is not None
+
+
+def _parse_letter_version(letter, number):
+    if letter:
+        # We consider there to be an implicit 0 in a pre-release if there is
+        # not a numeral associated with it.
+        if number is None:
+            number = 0
+
+        # We normalize any letters to their lower case form
+        letter = letter.lower()
+
+        # We consider some words to be alternate spellings of other words and
+        # in those cases we want to normalize the spellings to our preferred
+        # spelling.
+        if letter == "alpha":
+            letter = "a"
+        elif letter == "beta":
+            letter = "b"
+        elif letter in ["c", "pre", "preview"]:
+            letter = "rc"
+        elif letter in ["rev", "r"]:
+            letter = "post"
+
+        return letter, int(number)
+    if not letter and number:
+        # We assume if we are given a number, but we are not given a letter
+        # then this is using the implicit post release syntax (e.g. 1.0-1)
+        letter = "post"
+
+        return letter, int(number)
+
+
+_local_version_separators = re.compile(r"[\._-]")
+
+
+def _parse_local_version(local):
+    """
+    Takes a string like abc.1.twelve and turns it into ("abc", 1, "twelve").
+    """
+    if local is not None:
+        return tuple(
+            part.lower() if not part.isdigit() else int(part)
+            for part in _local_version_separators.split(local)
+        )
+
+
+def _cmpkey(epoch, release, pre, post, dev, local):
+    # When we compare a release version, we want to compare it with all of the
+    # trailing zeros removed. So we'll use a reverse the list, drop all the now
+    # leading zeros until we come to something non zero, then take the rest
+    # re-reverse it back into the correct order and make it a tuple and use
+    # that for our sorting key.
+    release = tuple(
+        reversed(list(itertools.dropwhile(lambda x: x == 0, reversed(release))))
+    )
+
+    # We need to "trick" the sorting algorithm to put 1.0.dev0 before 1.0a0.
+    # We'll do this by abusing the pre segment, but we _only_ want to do this
+    # if there is not a pre or a post segment. If we have one of those then
+    # the normal sorting rules will handle this case correctly.
+    if pre is None and post is None and dev is not None:
+        pre = -Infinity
+    # Versions without a pre-release (except as noted above) should sort after
+    # those with one.
+    elif pre is None:
+        pre = Infinity
+
+    # Versions without a post segment should sort before those with one.
+    if post is None:
+        post = -Infinity
+
+    # Versions without a development segment should sort after those with one.
+    if dev is None:
+        dev = Infinity
+
+    if local is None:
+        # Versions without a local segment should sort before those with one.
+        local = -Infinity
+    else:
+        # Versions with a local segment need that segment parsed to implement
+        # the sorting rules in PEP440.
+        # - Alpha numeric segments sort before numeric segments
+        # - Alpha numeric segments sort lexicographically
+        # - Numeric segments sort numerically
+        # - Shorter versions sort before longer versions when the prefixes
+        #   match exactly
+        local = tuple((i, "") if isinstance(i, int) else (-Infinity, i) for i in local)
+
+    return epoch, release, pre, post, dev, local