<h2>Editing File: /lib/python2.7/site-packages/pkg_resources/_vendor/packaging/requirements.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 string
import re

from pkg_resources.extern.pyparsing import stringStart, stringEnd, originalTextFor, ParseException
from pkg_resources.extern.pyparsing import ZeroOrMore, Word, Optional, Regex, Combine
from pkg_resources.extern.pyparsing import Literal as L  # noqa
from pkg_resources.extern.six.moves.urllib import parse as urlparse

from .markers import MARKER_EXPR, Marker
from .specifiers import LegacySpecifier, Specifier, SpecifierSet


class InvalidRequirement(ValueError):
    &quot;&quot;&quot;
    An invalid requirement was found, users should refer to PEP 508.
    &quot;&quot;&quot;


ALPHANUM = Word(string.ascii_letters + string.digits)

LBRACKET = L(&quot;[&quot;).suppress()
RBRACKET = L(&quot;]&quot;).suppress()
LPAREN = L(&quot;(&quot;).suppress()
RPAREN = L(&quot;)&quot;).suppress()
COMMA = L(&quot;,&quot;).suppress()
SEMICOLON = L(&quot;;&quot;).suppress()
AT = L(&quot;@&quot;).suppress()

PUNCTUATION = Word(&quot;-_.&quot;)
IDENTIFIER_END = ALPHANUM | (ZeroOrMore(PUNCTUATION) + ALPHANUM)
IDENTIFIER = Combine(ALPHANUM + ZeroOrMore(IDENTIFIER_END))

NAME = IDENTIFIER(&quot;name&quot;)
EXTRA = IDENTIFIER

URI = Regex(r'[^ ]+')(&quot;url&quot;)
URL = (AT + URI)

EXTRAS_LIST = EXTRA + ZeroOrMore(COMMA + EXTRA)
EXTRAS = (LBRACKET + Optional(EXTRAS_LIST) + RBRACKET)(&quot;extras&quot;)

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=&quot;,&quot;, adjacent=False)(&quot;_raw_spec&quot;)
_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)(&quot;specifier&quot;)
VERSION_SPEC.setParseAction(lambda s, l, t: t[1])

MARKER_EXPR = originalTextFor(MARKER_EXPR())(&quot;marker&quot;)
MARKER_EXPR.setParseAction(
    lambda s, l, t: Marker(s[t._original_start:t._original_end])
)
MARKER_SEPERATOR = SEMICOLON
MARKER = MARKER_SEPERATOR + 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


class Requirement(object):
    &quot;&quot;&quot;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.
    &quot;&quot;&quot;

    # 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(
                &quot;Invalid requirement, parse error at \&quot;{0!r}\&quot;&quot;.format(
                    requirement_string[e.loc:e.loc + 8]))

        self.name = req.name
        if req.url:
            parsed_url = urlparse.urlparse(req.url)
            if not (parsed_url.scheme and parsed_url.netloc) or (
                    not parsed_url.scheme and not parsed_url.netloc):
                raise InvalidRequirement(&quot;Invalid URL given&quot;)
            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(&quot;[{0}]&quot;.format(&quot;,&quot;.join(sorted(self.extras))))

        if self.specifier:
            parts.append(str(self.specifier))

        if self.url:
            parts.append(&quot;@ {0}&quot;.format(self.url))

        if self.marker:
            parts.append(&quot;; {0}&quot;.format(self.marker))

        return &quot;&quot;.join(parts)

    def __repr__(self):
        return &quot;&lt;Requirement({0!r})&gt;&quot;.format(str(self))
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