diff options
Diffstat (limited to 'Lib/importlib')
| -rw-r--r-- | Lib/importlib/metadata/__init__.py | 155 | ||||
| -rw-r--r-- | Lib/importlib/metadata/_meta.py | 52 |
2 files changed, 151 insertions, 56 deletions
diff --git a/Lib/importlib/metadata/__init__.py b/Lib/importlib/metadata/__init__.py index 41c2a4a6..c8e59ca 100644 --- a/Lib/importlib/metadata/__init__.py +++ b/Lib/importlib/metadata/__init__.py @@ -1,3 +1,5 @@ +from __future__ import annotations + import os import re import abc @@ -26,7 +28,7 @@ from contextlib import suppress from importlib import import_module from importlib.abc import MetaPathFinder from itertools import starmap -from typing import Iterable, List, Mapping, Optional, Set, Union, cast +from typing import Any, Iterable, List, Mapping, Match, Optional, Set, cast __all__ = [ 'Distribution', @@ -163,17 +165,17 @@ class EntryPoint: value: str group: str - dist: Optional['Distribution'] = None + dist: Optional[Distribution] = None def __init__(self, name: str, value: str, group: str) -> None: vars(self).update(name=name, value=value, group=group) - def load(self): + def load(self) -> Any: """Load the entry point from its definition. If only a module is indicated by the value, return that module. Otherwise, return the named object. """ - match = self.pattern.match(self.value) + match = cast(Match, self.pattern.match(self.value)) module = import_module(match.group('module')) attrs = filter(None, (match.group('attr') or '').split('.')) return functools.reduce(getattr, attrs, module) @@ -268,7 +270,7 @@ class EntryPoints(tuple): """ return '%s(%r)' % (self.__class__.__name__, tuple(self)) - def select(self, **params): + def select(self, **params) -> EntryPoints: """ Select entry points from self that match the given parameters (typically group and/or name). @@ -304,19 +306,17 @@ class EntryPoints(tuple): class PackagePath(pathlib.PurePosixPath): """A reference to a path in a package""" - hash: Optional["FileHash"] + hash: Optional[FileHash] size: int - dist: "Distribution" + dist: Distribution def read_text(self, encoding: str = 'utf-8') -> str: # type: ignore[override] - with self.locate().open(encoding=encoding) as stream: - return stream.read() + return self.locate().read_text(encoding=encoding) def read_binary(self) -> bytes: - with self.locate().open('rb') as stream: - return stream.read() + return self.locate().read_bytes() - def locate(self) -> pathlib.Path: + def locate(self) -> SimplePath: """Return a path-like object for this path""" return self.dist.locate_file(self) @@ -330,6 +330,7 @@ class FileHash: class DeprecatedNonAbstract: + # Required until Python 3.14 def __new__(cls, *args, **kwargs): all_names = { name for subclass in inspect.getmro(cls) for name in vars(subclass) @@ -349,25 +350,48 @@ class DeprecatedNonAbstract: class Distribution(DeprecatedNonAbstract): - """A Python distribution package.""" + """ + An abstract Python distribution package. + + Custom providers may derive from this class and define + the abstract methods to provide a concrete implementation + for their environment. Some providers may opt to override + the default implementation of some properties to bypass + the file-reading mechanism. + """ @abc.abstractmethod def read_text(self, filename) -> Optional[str]: """Attempt to load metadata file given by the name. + Python distribution metadata is organized by blobs of text + typically represented as "files" in the metadata directory + (e.g. package-1.0.dist-info). These files include things + like: + + - METADATA: The distribution metadata including fields + like Name and Version and Description. + - entry_points.txt: A series of entry points as defined in + `the entry points spec <https://packaging.python.org/en/latest/specifications/entry-points/#file-format>`_. + - RECORD: A record of files according to + `this recording spec <https://packaging.python.org/en/latest/specifications/recording-installed-packages/#the-record-file>`_. + + A package may provide any set of files, including those + not listed here or none at all. + :param filename: The name of the file in the distribution info. :return: The text if found, otherwise None. """ @abc.abstractmethod - def locate_file(self, path: Union[str, os.PathLike[str]]) -> pathlib.Path: + def locate_file(self, path: str | os.PathLike[str]) -> SimplePath: """ - Given a path to a file in this distribution, return a path + Given a path to a file in this distribution, return a SimplePath to it. """ @classmethod - def from_name(cls, name: str) -> "Distribution": + def from_name(cls, name: str) -> Distribution: """Return the Distribution for the given package name. :param name: The name of the distribution package to search for. @@ -385,16 +409,18 @@ class Distribution(DeprecatedNonAbstract): raise PackageNotFoundError(name) @classmethod - def discover(cls, **kwargs) -> Iterable["Distribution"]: + def discover( + cls, *, context: Optional[DistributionFinder.Context] = None, **kwargs + ) -> Iterable[Distribution]: """Return an iterable of Distribution objects for all packages. Pass a ``context`` or pass keyword arguments for constructing a context. :context: A ``DistributionFinder.Context`` object. - :return: Iterable of Distribution objects for all packages. + :return: Iterable of Distribution objects for packages matching + the context. """ - context = kwargs.pop('context', None) if context and kwargs: raise ValueError("cannot accept context and kwargs") context = context or DistributionFinder.Context(**kwargs) @@ -403,8 +429,8 @@ class Distribution(DeprecatedNonAbstract): ) @staticmethod - def at(path: Union[str, os.PathLike[str]]) -> "Distribution": - """Return a Distribution for the indicated metadata path + def at(path: str | os.PathLike[str]) -> Distribution: + """Return a Distribution for the indicated metadata path. :param path: a string or path-like object :return: a concrete Distribution instance for the path @@ -413,7 +439,7 @@ class Distribution(DeprecatedNonAbstract): @staticmethod def _discover_resolvers(): - """Search the meta_path for resolvers.""" + """Search the meta_path for resolvers (MetadataPathFinders).""" declared = ( getattr(finder, 'find_distributions', None) for finder in sys.meta_path ) @@ -424,7 +450,11 @@ class Distribution(DeprecatedNonAbstract): """Return the parsed metadata for this Distribution. The returned object will have keys that name the various bits of - metadata. See PEP 566 for details. + metadata per the + `Core metadata specifications <https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata>`_. + + Custom providers may provide the METADATA file or override this + property. """ opt_text = ( self.read_text('METADATA') @@ -454,6 +484,12 @@ class Distribution(DeprecatedNonAbstract): @property def entry_points(self) -> EntryPoints: + """ + Return EntryPoints for this distribution. + + Custom providers may provide the ``entry_points.txt`` file + or override this property. + """ return EntryPoints._from_text_for(self.read_text('entry_points.txt'), self) @property @@ -466,6 +502,10 @@ class Distribution(DeprecatedNonAbstract): (i.e. RECORD for dist-info, or installed-files.txt or SOURCES.txt for egg-info) is missing. Result may be empty if the metadata exists but is empty. + + Custom providers are recommended to provide a "RECORD" file (in + ``read_text``) or override this property to allow for callers to be + able to resolve filenames provided by the package. """ def make_file(name, hash=None, size_str=None): @@ -497,7 +537,7 @@ class Distribution(DeprecatedNonAbstract): def _read_files_distinfo(self): """ - Read the lines of RECORD + Read the lines of RECORD. """ text = self.read_text('RECORD') return text and text.splitlines() @@ -611,6 +651,9 @@ class Distribution(DeprecatedNonAbstract): class DistributionFinder(MetaPathFinder): """ A MetaPathFinder capable of discovering installed distributions. + + Custom providers should implement this interface in order to + supply metadata. """ class Context: @@ -623,6 +666,17 @@ class DistributionFinder(MetaPathFinder): Each DistributionFinder may expect any parameters and should attempt to honor the canonical parameters defined below when appropriate. + + This mechanism gives a custom provider a means to + solicit additional details from the caller beyond + "name" and "path" when searching distributions. + For example, imagine a provider that exposes suites + of packages in either a "public" or "private" ``realm``. + A caller may wish to query only for distributions in + a particular realm and could call + ``distributions(realm="private")`` to signal to the + custom provider to only include distributions from that + realm. """ name = None @@ -658,11 +712,18 @@ class DistributionFinder(MetaPathFinder): class FastPath: """ - Micro-optimized class for searching a path for - children. + Micro-optimized class for searching a root for children. + + Root is a path on the file system that may contain metadata + directories either as natural directories or within a zip file. >>> FastPath('').children() ['...'] + + FastPath objects are cached and recycled for any given root. + + >>> FastPath('foobar') is FastPath('foobar') + True """ @functools.lru_cache() # type: ignore @@ -704,7 +765,19 @@ class FastPath: class Lookup: + """ + A micro-optimized class for searching a (fast) path for metadata. + """ + def __init__(self, path: FastPath): + """ + Calculate all of the children representing metadata. + + From the children in the path, calculate early all of the + children that appear to represent metadata (infos) or legacy + metadata (eggs). + """ + base = os.path.basename(path.root).lower() base_is_egg = base.endswith(".egg") self.infos = FreezableDefaultDict(list) @@ -725,7 +798,10 @@ class Lookup: self.infos.freeze() self.eggs.freeze() - def search(self, prepared): + def search(self, prepared: Prepared): + """ + Yield all infos and eggs matching the Prepared query. + """ infos = ( self.infos[prepared.normalized] if prepared @@ -741,13 +817,28 @@ class Lookup: class Prepared: """ - A prepared search for metadata on a possibly-named package. + A prepared search query for metadata on a possibly-named package. + + Pre-calculates the normalization to prevent repeated operations. + + >>> none = Prepared(None) + >>> none.normalized + >>> none.legacy_normalized + >>> bool(none) + False + >>> sample = Prepared('Sample__Pkg-name.foo') + >>> sample.normalized + 'sample_pkg_name_foo' + >>> sample.legacy_normalized + 'sample__pkg_name.foo' + >>> bool(sample) + True """ normalized = None legacy_normalized = None - def __init__(self, name): + def __init__(self, name: Optional[str]): self.name = name if name is None: return @@ -777,7 +868,7 @@ class MetadataPathFinder(DistributionFinder): @classmethod def find_distributions( cls, context=DistributionFinder.Context() - ) -> Iterable["PathDistribution"]: + ) -> Iterable[PathDistribution]: """ Find distributions. @@ -810,7 +901,7 @@ class PathDistribution(Distribution): """ self._path = path - def read_text(self, filename: Union[str, os.PathLike[str]]) -> Optional[str]: + def read_text(self, filename: str | os.PathLike[str]) -> Optional[str]: with suppress( FileNotFoundError, IsADirectoryError, @@ -824,7 +915,7 @@ class PathDistribution(Distribution): read_text.__doc__ = Distribution.read_text.__doc__ - def locate_file(self, path: Union[str, os.PathLike[str]]) -> pathlib.Path: + def locate_file(self, path: str | os.PathLike[str]) -> SimplePath: return self._path.parent / path @property diff --git a/Lib/importlib/metadata/_meta.py b/Lib/importlib/metadata/_meta.py index f670016..1927d0f 100644 --- a/Lib/importlib/metadata/_meta.py +++ b/Lib/importlib/metadata/_meta.py @@ -1,3 +1,6 @@ +from __future__ import annotations + +import os from typing import Protocol from typing import Any, Dict, Iterator, List, Optional, TypeVar, Union, overload @@ -6,30 +9,27 @@ _T = TypeVar("_T") class PackageMetadata(Protocol): - def __len__(self) -> int: - ... # pragma: no cover + def __len__(self) -> int: ... # pragma: no cover - def __contains__(self, item: str) -> bool: - ... # pragma: no cover + def __contains__(self, item: str) -> bool: ... # pragma: no cover - def __getitem__(self, key: str) -> str: - ... # pragma: no cover + def __getitem__(self, key: str) -> str: ... # pragma: no cover - def __iter__(self) -> Iterator[str]: - ... # pragma: no cover + def __iter__(self) -> Iterator[str]: ... # pragma: no cover @overload - def get(self, name: str, failobj: None = None) -> Optional[str]: - ... # pragma: no cover + def get( + self, name: str, failobj: None = None + ) -> Optional[str]: ... # pragma: no cover @overload - def get(self, name: str, failobj: _T) -> Union[str, _T]: - ... # pragma: no cover + def get(self, name: str, failobj: _T) -> Union[str, _T]: ... # pragma: no cover # overload per python/importlib_metadata#435 @overload - def get_all(self, name: str, failobj: None = None) -> Optional[List[Any]]: - ... # pragma: no cover + def get_all( + self, name: str, failobj: None = None + ) -> Optional[List[Any]]: ... # pragma: no cover @overload def get_all(self, name: str, failobj: _T) -> Union[List[Any], _T]: @@ -44,20 +44,24 @@ class PackageMetadata(Protocol): """ -class SimplePath(Protocol[_T]): +class SimplePath(Protocol): """ - A minimal subset of pathlib.Path required by PathDistribution. + A minimal subset of pathlib.Path required by Distribution. """ - def joinpath(self, other: Union[str, _T]) -> _T: - ... # pragma: no cover + def joinpath( + self, other: Union[str, os.PathLike[str]] + ) -> SimplePath: ... # pragma: no cover - def __truediv__(self, other: Union[str, _T]) -> _T: - ... # pragma: no cover + def __truediv__( + self, other: Union[str, os.PathLike[str]] + ) -> SimplePath: ... # pragma: no cover @property - def parent(self) -> _T: - ... # pragma: no cover + def parent(self) -> SimplePath: ... # pragma: no cover + + def read_text(self, encoding=None) -> str: ... # pragma: no cover + + def read_bytes(self) -> bytes: ... # pragma: no cover - def read_text(self) -> str: - ... # pragma: no cover + def exists(self) -> bool: ... # pragma: no cover |