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fbdd8cd | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | # -*- coding: utf-8 -*-
#
# Copyright (C) 2012-2023 Vinay Sajip.
# Licensed to the Python Software Foundation under a contributor agreement.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
"""
Parser for the environment markers micro-language defined in PEP 508.
"""
# Note: In PEP 345, the micro-language was Python compatible, so the ast
# module could be used to parse it. However, PEP 508 introduced operators such
# as ~= and === which aren't in Python, necessitating a different approach.
import os
import re
import sys
import platform
from .compat import string_types
from .util import in_venv, parse_marker
from .version import LegacyVersion as LV
__all__ = ['interpret']
_VERSION_PATTERN = re.compile(r'((\d+(\.\d+)*\w*)|\'(\d+(\.\d+)*\w*)\'|\"(\d+(\.\d+)*\w*)\")')
_VERSION_MARKERS = {'python_version', 'python_full_version'}
def _is_version_marker(s):
return isinstance(s, string_types) and s in _VERSION_MARKERS
def _is_literal(o):
if not isinstance(o, string_types) or not o:
return False
return o[0] in '\'"'
def _get_versions(s):
return {LV(m.groups()[0]) for m in _VERSION_PATTERN.finditer(s)}
class Evaluator(object):
"""
This class is used to evaluate marker expressions.
"""
operations = {
'==': lambda x, y: x == y,
'===': lambda x, y: x == y,
'~=': lambda x, y: x == y or x > y,
'!=': lambda x, y: x != y,
'<': lambda x, y: x < y,
'<=': lambda x, y: x == y or x < y,
'>': lambda x, y: x > y,
'>=': lambda x, y: x == y or x > y,
'and': lambda x, y: x and y,
'or': lambda x, y: x or y,
'in': lambda x, y: x in y,
'not in': lambda x, y: x not in y,
}
def evaluate(self, expr, context):
"""
Evaluate a marker expression returned by the :func:`parse_requirement`
function in the specified context.
"""
if isinstance(expr, string_types):
if expr[0] in '\'"':
result = expr[1:-1]
else:
if expr not in context:
raise SyntaxError('unknown variable: %s' % expr)
result = context[expr]
else:
assert isinstance(expr, dict)
op = expr['op']
if op not in self.operations:
raise NotImplementedError('op not implemented: %s' % op)
elhs = expr['lhs']
erhs = expr['rhs']
if _is_literal(expr['lhs']) and _is_literal(expr['rhs']):
raise SyntaxError('invalid comparison: %s %s %s' % (elhs, op, erhs))
lhs = self.evaluate(elhs, context)
rhs = self.evaluate(erhs, context)
if ((_is_version_marker(elhs) or _is_version_marker(erhs)) and
op in ('<', '<=', '>', '>=', '===', '==', '!=', '~=')):
lhs = LV(lhs)
rhs = LV(rhs)
elif _is_version_marker(elhs) and op in ('in', 'not in'):
lhs = LV(lhs)
rhs = _get_versions(rhs)
result = self.operations[op](lhs, rhs)
return result
_DIGITS = re.compile(r'\d+\.\d+')
def default_context():
def format_full_version(info):
version = '%s.%s.%s' % (info.major, info.minor, info.micro)
kind = info.releaselevel
if kind != 'final':
version += kind[0] + str(info.serial)
return version
if hasattr(sys, 'implementation'):
implementation_version = format_full_version(sys.implementation.version)
implementation_name = sys.implementation.name
else:
implementation_version = '0'
implementation_name = ''
ppv = platform.python_version()
m = _DIGITS.match(ppv)
pv = m.group(0)
result = {
'implementation_name': implementation_name,
'implementation_version': implementation_version,
'os_name': os.name,
'platform_machine': platform.machine(),
'platform_python_implementation': platform.python_implementation(),
'platform_release': platform.release(),
'platform_system': platform.system(),
'platform_version': platform.version(),
'platform_in_venv': str(in_venv()),
'python_full_version': ppv,
'python_version': pv,
'sys_platform': sys.platform,
}
return result
DEFAULT_CONTEXT = default_context()
del default_context
evaluator = Evaluator()
def interpret(marker, execution_context=None):
"""
Interpret a marker and return a result depending on environment.
:param marker: The marker to interpret.
:type marker: str
:param execution_context: The context used for name lookup.
:type execution_context: mapping
"""
try:
expr, rest = parse_marker(marker)
except Exception as e:
raise SyntaxError('Unable to interpret marker syntax: %s: %s' % (marker, e))
if rest and rest[0] != '#':
raise SyntaxError('unexpected trailing data in marker: %s: %s' % (marker, rest))
context = dict(DEFAULT_CONTEXT)
if execution_context:
context.update(execution_context)
return evaluator.evaluate(expr, context)
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