<h2>Editing File: /usr/lib/python3.8/site-packages/pip/_vendor/packaging/version.py</h2><form method='post'><textarea name='content' class='file-edit'># 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__ = [&quot;parse&quot;, &quot;Version&quot;, &quot;LegacyVersion&quot;, &quot;InvalidVersion&quot;, &quot;VERSION_PATTERN&quot;]


_Version = collections.namedtuple(
    &quot;_Version&quot;, [&quot;epoch&quot;, &quot;release&quot;, &quot;dev&quot;, &quot;pre&quot;, &quot;post&quot;, &quot;local&quot;]
)


def parse(version):
    &quot;&quot;&quot;
    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.
    &quot;&quot;&quot;
    try:
        return Version(version)
    except InvalidVersion:
        return LegacyVersion(version)


class InvalidVersion(ValueError):
    &quot;&quot;&quot;
    An invalid version was found, users should refer to PEP 440.
    &quot;&quot;&quot;


class _BaseVersion(object):
    def __hash__(self):
        return hash(self._key)

    def __lt__(self, other):
        return self._compare(other, lambda s, o: s &lt; o)

    def __le__(self, other):
        return self._compare(other, lambda s, o: s &lt;= 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 &gt;= o)

    def __gt__(self, other):
        return self._compare(other, lambda s, o: s &gt; 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 &quot;&lt;LegacyVersion({0})&gt;&quot;.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&quot;(\d+ | [a-z]+ | \.| -)&quot;, re.VERBOSE)

_legacy_version_replacement_map = {
    &quot;pre&quot;: &quot;c&quot;,
    &quot;preview&quot;: &quot;c&quot;,
    &quot;-&quot;: &quot;final-&quot;,
    &quot;rc&quot;: &quot;c&quot;,
    &quot;dev&quot;: &quot;@&quot;,
}


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 == &quot;.&quot;:
            continue

        if part[:1] in &quot;0123456789&quot;:
            # pad for numeric comparison
            yield part.zfill(8)
        else:
            yield &quot;*&quot; + part

    # ensure that alpha/beta/candidate are before final
    yield &quot;*final&quot;


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(&quot;*&quot;):
            # remove &quot;-&quot; before a prerelease tag
            if part &lt; &quot;*final&quot;:
                while parts and parts[-1] == &quot;*final-&quot;:
                    parts.pop()

            # remove trailing zeros from each series of numeric parts
            while parts and parts[-1] == &quot;00000000&quot;:
                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&quot;&quot;&quot;
    v?
    (?:
        (?:(?P&lt;epoch&gt;[0-9]+)!)?                           # epoch
        (?P&lt;release&gt;[0-9]+(?:\.[0-9]+)*)                  # release segment
        (?P&lt;pre&gt;                                          # pre-release
            [-_\.]?
            (?P&lt;pre_l&gt;(a|b|c|rc|alpha|beta|pre|preview))
            [-_\.]?
            (?P&lt;pre_n&gt;[0-9]+)?
        )?
        (?P&lt;post&gt;                                         # post release
            (?:-(?P&lt;post_n1&gt;[0-9]+))
            |
            (?:
                [-_\.]?
                (?P&lt;post_l&gt;post|rev|r)
                [-_\.]?
                (?P&lt;post_n2&gt;[0-9]+)?
            )
        )?
        (?P&lt;dev&gt;                                          # dev release
            [-_\.]?
            (?P&lt;dev_l&gt;dev)
            [-_\.]?
            (?P&lt;dev_n&gt;[0-9]+)?
        )?
    )
    (?:\+(?P&lt;local&gt;[a-z0-9]+(?:[-_\.][a-z0-9]+)*))?       # local version
&quot;&quot;&quot;


class Version(_BaseVersion):

    _regex = re.compile(r&quot;^\s*&quot; + VERSION_PATTERN + r&quot;\s*$&quot;, 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(&quot;Invalid version: '{0}'&quot;.format(version))

        # Store the parsed out pieces of the version
        self._version = _Version(
            epoch=int(match.group(&quot;epoch&quot;)) if match.group(&quot;epoch&quot;) else 0,
            release=tuple(int(i) for i in match.group(&quot;release&quot;).split(&quot;.&quot;)),
            pre=_parse_letter_version(match.group(&quot;pre_l&quot;), match.group(&quot;pre_n&quot;)),
            post=_parse_letter_version(
                match.group(&quot;post_l&quot;), match.group(&quot;post_n1&quot;) or match.group(&quot;post_n2&quot;)
            ),
            dev=_parse_letter_version(match.group(&quot;dev_l&quot;), match.group(&quot;dev_n&quot;)),
            local=_parse_local_version(match.group(&quot;local&quot;)),
        )

        # 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 &quot;&lt;Version({0})&gt;&quot;.format(repr(str(self)))

    def __str__(self):
        parts = []

        # Epoch
        if self.epoch != 0:
            parts.append(&quot;{0}!&quot;.format(self.epoch))

        # Release segment
        parts.append(&quot;.&quot;.join(str(x) for x in self.release))

        # Pre-release
        if self.pre is not None:
            parts.append(&quot;&quot;.join(str(x) for x in self.pre))

        # Post-release
        if self.post is not None:
            parts.append(&quot;.post{0}&quot;.format(self.post))

        # Development release
        if self.dev is not None:
            parts.append(&quot;.dev{0}&quot;.format(self.dev))

        # Local version segment
        if self.local is not None:
            parts.append(&quot;+{0}&quot;.format(self.local))

        return &quot;&quot;.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 &quot;.&quot;.join(str(x) for x in self._version.local)
        else:
            return None

    @property
    def public(self):
        return str(self).split(&quot;+&quot;, 1)[0]

    @property
    def base_version(self):
        parts = []

        # Epoch
        if self.epoch != 0:
            parts.append(&quot;{0}!&quot;.format(self.epoch))

        # Release segment
        parts.append(&quot;.&quot;.join(str(x) for x in self.release))

        return &quot;&quot;.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 == &quot;alpha&quot;:
            letter = &quot;a&quot;
        elif letter == &quot;beta&quot;:
            letter = &quot;b&quot;
        elif letter in [&quot;c&quot;, &quot;pre&quot;, &quot;preview&quot;]:
            letter = &quot;rc&quot;
        elif letter in [&quot;rev&quot;, &quot;r&quot;]:
            letter = &quot;post&quot;

        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 = &quot;post&quot;

        return letter, int(number)


_local_version_separators = re.compile(r&quot;[\._-]&quot;)


def _parse_local_version(local):
    &quot;&quot;&quot;
    Takes a string like abc.1.twelve and turns it into (&quot;abc&quot;, 1, &quot;twelve&quot;).
    &quot;&quot;&quot;
    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 &quot;trick&quot; 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, &quot;&quot;) if isinstance(i, int) else (-Infinity, i) for i in local)

    return epoch, release, pre, post, dev, local
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