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# 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): 

""" 

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_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): 

"""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( 

"Invalid requirement, parse error at \"{0!r}\"".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("Invalid URL given") 

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("; {0}".format(self.marker)) 

 

return "".join(parts) 

 

def __repr__(self): 

return "<Requirement({0!r})>".format(str(self))