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186 lines
5.6 KiB
186 lines
5.6 KiB
3 years ago
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import os
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import io
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from . import _common
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from ._common import as_file, files
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from .abc import ResourceReader
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from contextlib import suppress
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from importlib.abc import ResourceLoader
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from importlib.machinery import ModuleSpec
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from io import BytesIO, TextIOWrapper
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from pathlib import Path
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from types import ModuleType
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from typing import ContextManager, Iterable, Union
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from typing import cast
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from typing.io import BinaryIO, TextIO
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from collections.abc import Sequence
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from functools import singledispatch
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__all__ = [
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'Package',
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'Resource',
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'ResourceReader',
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'as_file',
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'contents',
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'files',
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'is_resource',
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'open_binary',
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'open_text',
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'path',
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'read_binary',
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'read_text',
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]
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Package = Union[str, ModuleType]
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Resource = Union[str, os.PathLike]
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def open_binary(package: Package, resource: Resource) -> BinaryIO:
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"""Return a file-like object opened for binary reading of the resource."""
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resource = _common.normalize_path(resource)
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package = _common.get_package(package)
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reader = _common.get_resource_reader(package)
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if reader is not None:
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return reader.open_resource(resource)
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spec = cast(ModuleSpec, package.__spec__)
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# Using pathlib doesn't work well here due to the lack of 'strict'
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# argument for pathlib.Path.resolve() prior to Python 3.6.
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if spec.submodule_search_locations is not None:
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paths = spec.submodule_search_locations
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elif spec.origin is not None:
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paths = [os.path.dirname(os.path.abspath(spec.origin))]
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for package_path in paths:
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full_path = os.path.join(package_path, resource)
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try:
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return open(full_path, mode='rb')
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except OSError:
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# Just assume the loader is a resource loader; all the relevant
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# importlib.machinery loaders are and an AttributeError for
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# get_data() will make it clear what is needed from the loader.
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loader = cast(ResourceLoader, spec.loader)
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data = None
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if hasattr(spec.loader, 'get_data'):
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with suppress(OSError):
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data = loader.get_data(full_path)
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if data is not None:
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return BytesIO(data)
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raise FileNotFoundError(f'{resource!r} resource not found in {spec.name!r}')
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def open_text(
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package: Package,
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resource: Resource,
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encoding: str = 'utf-8',
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errors: str = 'strict',
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) -> TextIO:
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"""Return a file-like object opened for text reading of the resource."""
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return TextIOWrapper(
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open_binary(package, resource), encoding=encoding, errors=errors
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)
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def read_binary(package: Package, resource: Resource) -> bytes:
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"""Return the binary contents of the resource."""
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with open_binary(package, resource) as fp:
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return fp.read()
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def read_text(
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package: Package,
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resource: Resource,
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encoding: str = 'utf-8',
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errors: str = 'strict',
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) -> str:
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"""Return the decoded string of the resource.
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The decoding-related arguments have the same semantics as those of
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bytes.decode().
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"""
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with open_text(package, resource, encoding, errors) as fp:
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return fp.read()
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def path(
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package: Package,
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resource: Resource,
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) -> 'ContextManager[Path]':
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"""A context manager providing a file path object to the resource.
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If the resource does not already exist on its own on the file system,
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a temporary file will be created. If the file was created, the file
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will be deleted upon exiting the context manager (no exception is
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raised if the file was deleted prior to the context manager
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exiting).
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"""
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reader = _common.get_resource_reader(_common.get_package(package))
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return (
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_path_from_reader(reader, _common.normalize_path(resource))
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if reader
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else _common.as_file(
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_common.files(package).joinpath(_common.normalize_path(resource))
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)
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)
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def _path_from_reader(reader, resource):
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return _path_from_resource_path(reader, resource) or _path_from_open_resource(
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reader, resource
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)
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def _path_from_resource_path(reader, resource):
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with suppress(FileNotFoundError):
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return Path(reader.resource_path(resource))
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def _path_from_open_resource(reader, resource):
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saved = io.BytesIO(reader.open_resource(resource).read())
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return _common._tempfile(saved.read, suffix=resource)
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def is_resource(package: Package, name: str) -> bool:
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"""True if 'name' is a resource inside 'package'.
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Directories are *not* resources.
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"""
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package = _common.get_package(package)
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_common.normalize_path(name)
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reader = _common.get_resource_reader(package)
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if reader is not None:
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return reader.is_resource(name)
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package_contents = set(contents(package))
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if name not in package_contents:
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return False
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return (_common.from_package(package) / name).is_file()
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def contents(package: Package) -> Iterable[str]:
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"""Return an iterable of entries in 'package'.
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Note that not all entries are resources. Specifically, directories are
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not considered resources. Use `is_resource()` on each entry returned here
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to check if it is a resource or not.
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"""
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package = _common.get_package(package)
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reader = _common.get_resource_reader(package)
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if reader is not None:
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return _ensure_sequence(reader.contents())
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transversable = _common.from_package(package)
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if transversable.is_dir():
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return list(item.name for item in transversable.iterdir())
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return []
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@singledispatch
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def _ensure_sequence(iterable):
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return list(iterable)
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@_ensure_sequence.register(Sequence)
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def _(iterable):
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return iterable
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