128 lines
4.2 KiB
Python
128 lines
4.2 KiB
Python
import contextlib
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import functools
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import os
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import sys
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from typing import TYPE_CHECKING, List, Optional, Type, cast
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from pip._internal.utils.misc import strtobool
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from .base import BaseDistribution, BaseEnvironment, FilesystemWheel, MemoryWheel, Wheel
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if TYPE_CHECKING:
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from typing import Protocol
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else:
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Protocol = object
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__all__ = [
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"BaseDistribution",
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"BaseEnvironment",
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"FilesystemWheel",
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"MemoryWheel",
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"Wheel",
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"get_default_environment",
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"get_environment",
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"get_wheel_distribution",
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"select_backend",
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]
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def _should_use_importlib_metadata() -> bool:
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"""Whether to use the ``importlib.metadata`` or ``pkg_resources`` backend.
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By default, pip uses ``importlib.metadata`` on Python 3.11+, and
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``pkg_resourcess`` otherwise. This can be overridden by a couple of ways:
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* If environment variable ``_PIP_USE_IMPORTLIB_METADATA`` is set, it
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dictates whether ``importlib.metadata`` is used, regardless of Python
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version.
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* On Python 3.11+, Python distributors can patch ``importlib.metadata``
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to add a global constant ``_PIP_USE_IMPORTLIB_METADATA = False``. This
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makes pip use ``pkg_resources`` (unless the user set the aforementioned
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environment variable to *True*).
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"""
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with contextlib.suppress(KeyError, ValueError):
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return bool(strtobool(os.environ["_PIP_USE_IMPORTLIB_METADATA"]))
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if sys.version_info < (3, 11):
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return False
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import importlib.metadata
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return bool(getattr(importlib.metadata, "_PIP_USE_IMPORTLIB_METADATA", True))
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class Backend(Protocol):
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Distribution: Type[BaseDistribution]
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Environment: Type[BaseEnvironment]
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@functools.lru_cache(maxsize=None)
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def select_backend() -> Backend:
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if _should_use_importlib_metadata():
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from . import importlib
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return cast(Backend, importlib)
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from . import pkg_resources
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return cast(Backend, pkg_resources)
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def get_default_environment() -> BaseEnvironment:
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"""Get the default representation for the current environment.
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This returns an Environment instance from the chosen backend. The default
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Environment instance should be built from ``sys.path`` and may use caching
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to share instance state accorss calls.
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"""
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return select_backend().Environment.default()
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def get_environment(paths: Optional[List[str]]) -> BaseEnvironment:
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"""Get a representation of the environment specified by ``paths``.
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This returns an Environment instance from the chosen backend based on the
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given import paths. The backend must build a fresh instance representing
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the state of installed distributions when this function is called.
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"""
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return select_backend().Environment.from_paths(paths)
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def get_directory_distribution(directory: str) -> BaseDistribution:
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"""Get the distribution metadata representation in the specified directory.
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This returns a Distribution instance from the chosen backend based on
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the given on-disk ``.dist-info`` directory.
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"""
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return select_backend().Distribution.from_directory(directory)
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def get_wheel_distribution(wheel: Wheel, canonical_name: str) -> BaseDistribution:
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"""Get the representation of the specified wheel's distribution metadata.
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This returns a Distribution instance from the chosen backend based on
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the given wheel's ``.dist-info`` directory.
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:param canonical_name: Normalized project name of the given wheel.
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"""
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return select_backend().Distribution.from_wheel(wheel, canonical_name)
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def get_metadata_distribution(
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metadata_contents: bytes,
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filename: str,
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canonical_name: str,
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) -> BaseDistribution:
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"""Get the dist representation of the specified METADATA file contents.
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This returns a Distribution instance from the chosen backend sourced from the data
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in `metadata_contents`.
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:param metadata_contents: Contents of a METADATA file within a dist, or one served
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via PEP 658.
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:param filename: Filename for the dist this metadata represents.
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:param canonical_name: Normalized project name of the given dist.
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"""
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return select_backend().Distribution.from_metadata_file_contents(
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metadata_contents,
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filename,
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canonical_name,
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)
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