bazarr/libs/importlib_resources/_common.py

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import os
import pathlib
import tempfile
import functools
import contextlib
import types
import importlib
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import inspect
import warnings
import itertools
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from typing import Union, Optional, cast
from .abc import ResourceReader, Traversable
from ._compat import wrap_spec
Package = Union[types.ModuleType, str]
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Anchor = Package
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def package_to_anchor(func):
"""
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Replace 'package' parameter as 'anchor' and warn about the change.
Other errors should fall through.
>>> files('a', 'b')
Traceback (most recent call last):
TypeError: files() takes from 0 to 1 positional arguments but 2 were given
"""
undefined = object()
@functools.wraps(func)
def wrapper(anchor=undefined, package=undefined):
if package is not undefined:
if anchor is not undefined:
return func(anchor, package)
warnings.warn(
"First parameter to files is renamed to 'anchor'",
DeprecationWarning,
stacklevel=2,
)
return func(package)
elif anchor is undefined:
return func()
return func(anchor)
return wrapper
@package_to_anchor
def files(anchor: Optional[Anchor] = None) -> Traversable:
"""
Get a Traversable resource for an anchor.
"""
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return from_package(resolve(anchor))
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def get_resource_reader(package: types.ModuleType) -> Optional[ResourceReader]:
"""
Return the package's loader if it's a ResourceReader.
"""
# We can't use
# a issubclass() check here because apparently abc.'s __subclasscheck__()
# hook wants to create a weak reference to the object, but
# zipimport.zipimporter does not support weak references, resulting in a
# TypeError. That seems terrible.
spec = package.__spec__
reader = getattr(spec.loader, 'get_resource_reader', None) # type: ignore
if reader is None:
return None
return reader(spec.name) # type: ignore
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@functools.singledispatch
def resolve(cand: Optional[Anchor]) -> types.ModuleType:
return cast(types.ModuleType, cand)
@resolve.register
def _(cand: str) -> types.ModuleType:
return importlib.import_module(cand)
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@resolve.register
def _(cand: None) -> types.ModuleType:
return resolve(_infer_caller().f_globals['__name__'])
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def _infer_caller():
"""
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Walk the stack and find the frame of the first caller not in this module.
"""
def is_this_file(frame_info):
return frame_info.filename == __file__
def is_wrapper(frame_info):
return frame_info.function == 'wrapper'
not_this_file = itertools.filterfalse(is_this_file, inspect.stack())
# also exclude 'wrapper' due to singledispatch in the call stack
callers = itertools.filterfalse(is_wrapper, not_this_file)
return next(callers).frame
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def from_package(package: types.ModuleType):
"""
Return a Traversable object for the given package.
"""
spec = wrap_spec(package)
reader = spec.loader.get_resource_reader(spec.name)
return reader.files()
@contextlib.contextmanager
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def _tempfile(
reader,
suffix='',
# gh-93353: Keep a reference to call os.remove() in late Python
# finalization.
*,
_os_remove=os.remove,
):
# Not using tempfile.NamedTemporaryFile as it leads to deeper 'try'
# blocks due to the need to close the temporary file to work on Windows
# properly.
fd, raw_path = tempfile.mkstemp(suffix=suffix)
try:
try:
os.write(fd, reader())
finally:
os.close(fd)
del reader
yield pathlib.Path(raw_path)
finally:
try:
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_os_remove(raw_path)
except FileNotFoundError:
pass
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def _temp_file(path):
return _tempfile(path.read_bytes, suffix=path.name)
def _is_present_dir(path: Traversable) -> bool:
"""
Some Traversables implement ``is_dir()`` to raise an
exception (i.e. ``FileNotFoundError``) when the
directory doesn't exist. This function wraps that call
to always return a boolean and only return True
if there's a dir and it exists.
"""
with contextlib.suppress(FileNotFoundError):
return path.is_dir()
return False
@functools.singledispatch
def as_file(path):
"""
Given a Traversable object, return that object as a
path on the local file system in a context manager.
"""
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return _temp_dir(path) if _is_present_dir(path) else _temp_file(path)
@as_file.register(pathlib.Path)
@contextlib.contextmanager
def _(path):
"""
Degenerate behavior for pathlib.Path objects.
"""
yield path
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@contextlib.contextmanager
def _temp_path(dir: tempfile.TemporaryDirectory):
"""
Wrap tempfile.TemporyDirectory to return a pathlib object.
"""
with dir as result:
yield pathlib.Path(result)
@contextlib.contextmanager
def _temp_dir(path):
"""
Given a traversable dir, recursively replicate the whole tree
to the file system in a context manager.
"""
assert path.is_dir()
with _temp_path(tempfile.TemporaryDirectory()) as temp_dir:
yield _write_contents(temp_dir, path)
def _write_contents(target, source):
child = target.joinpath(source.name)
if source.is_dir():
child.mkdir()
for item in source.iterdir():
_write_contents(child, item)
else:
child.open('wb').write(source.read_bytes())
return child