84 lines
1.9 KiB
Python
84 lines
1.9 KiB
Python
from contextlib import suppress
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from . import abc
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class SpecLoaderAdapter:
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"""
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Adapt a package spec to adapt the underlying loader.
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"""
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def __init__(self, spec, adapter=lambda spec: spec.loader):
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self.spec = spec
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self.loader = adapter(spec)
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def __getattr__(self, name):
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return getattr(self.spec, name)
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class TraversableResourcesLoader:
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"""
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Adapt a loader to provide TraversableResources.
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"""
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def __init__(self, spec):
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self.spec = spec
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def get_resource_reader(self, name):
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return DegenerateFiles(self.spec)._native()
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class DegenerateFiles:
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"""
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Adapter for an existing or non-existant resource reader
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to provide a degenerate .files().
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"""
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class Path(abc.Traversable):
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def iterdir(self):
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return iter(())
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def is_dir(self):
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return False
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is_file = exists = is_dir # type: ignore
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def joinpath(self, other):
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return DegenerateFiles.Path()
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@property
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def name(self):
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return ''
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def open(self, mode='rb', *args, **kwargs):
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raise ValueError()
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def __init__(self, spec):
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self.spec = spec
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@property
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def _reader(self):
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with suppress(AttributeError):
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return self.spec.loader.get_resource_reader(self.spec.name)
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def _native(self):
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"""
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Return the native reader if it supports files().
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"""
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reader = self._reader
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return reader if hasattr(reader, 'files') else self
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def __getattr__(self, attr):
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return getattr(self._reader, attr)
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def files(self):
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return DegenerateFiles.Path()
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def wrap_spec(package):
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"""
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Construct a package spec with traversable compatibility
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on the spec/loader/reader.
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"""
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return SpecLoaderAdapter(package.__spec__, TraversableResourcesLoader)
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