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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.
- import operator
- import os
- import platform
- import sys
- from typing import Any, Callable, Dict, List, Optional, Tuple, Union
- from pyparsing import ( # noqa: N817
- Forward,
- Group,
- Literal as L,
- ParseException,
- ParseResults,
- QuotedString,
- ZeroOrMore,
- stringEnd,
- stringStart,
- )
- from .specifiers import InvalidSpecifier, Specifier
- __all__ = [
- "InvalidMarker",
- "UndefinedComparison",
- "UndefinedEnvironmentName",
- "Marker",
- "default_environment",
- ]
- Operator = Callable[[str, str], bool]
- 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:
- def __init__(self, value: Any) -> None:
- self.value = value
- def __str__(self) -> str:
- return str(self.value)
- def __repr__(self) -> str:
- return f"<{self.__class__.__name__}('{self}')>"
- def serialize(self) -> str:
- raise NotImplementedError
- class Variable(Node):
- def serialize(self) -> str:
- return str(self)
- class Value(Node):
- def serialize(self) -> str:
- return f'"{self}"'
- class Op(Node):
- def serialize(self) -> str:
- 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") # PEP-345
- | L("sys.platform") # PEP-345
- | L("platform.version") # PEP-345
- | L("platform.machine") # PEP-345
- | L("platform.python_implementation") # PEP-345
- | L("python_implementation") # undocumented setuptools legacy
- | L("extra") # PEP-508
- )
- 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: Union[ParseResults, List[Any]]) -> List[Any]:
- if isinstance(results, ParseResults):
- return [_coerce_parse_result(i) for i in results]
- else:
- return results
- def _format_marker(
- marker: Union[List[str], Tuple[Node, ...], str], first: Optional[bool] = True
- ) -> str:
- assert isinstance(marker, (list, tuple, str))
- # 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: Dict[str, Operator] = {
- "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: str, op: Op, rhs: str) -> bool:
- try:
- spec = Specifier("".join([op.serialize(), rhs]))
- except InvalidSpecifier:
- pass
- else:
- return spec.contains(lhs)
- oper: Optional[Operator] = _operators.get(op.serialize())
- if oper is None:
- raise UndefinedComparison(f"Undefined {op!r} on {lhs!r} and {rhs!r}.")
- return oper(lhs, rhs)
- class Undefined:
- pass
- _undefined = Undefined()
- def _get_env(environment: Dict[str, str], name: str) -> str:
- value: Union[str, Undefined] = environment.get(name, _undefined)
- if isinstance(value, Undefined):
- raise UndefinedEnvironmentName(
- f"{name!r} does not exist in evaluation environment."
- )
- return value
- def _evaluate_markers(markers: List[Any], environment: Dict[str, str]) -> bool:
- groups: List[List[bool]] = [[]]
- for marker in markers:
- assert isinstance(marker, (list, tuple, str))
- 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: "sys._version_info") -> str:
- 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() -> Dict[str, str]:
- iver = format_full_version(sys.implementation.version)
- implementation_name = sys.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:
- def __init__(self, marker: str) -> None:
- try:
- self._markers = _coerce_parse_result(MARKER.parseString(marker))
- except ParseException as e:
- raise InvalidMarker(
- f"Invalid marker: {marker!r}, parse error at "
- f"{marker[e.loc : e.loc + 8]!r}"
- )
- def __str__(self) -> str:
- return _format_marker(self._markers)
- def __repr__(self) -> str:
- return f"<Marker('{self}')>"
- def evaluate(self, environment: Optional[Dict[str, str]] = None) -> bool:
- """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)
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