44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
"""A module proxy for delayed importing of modules.
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From http://barnesc.blogspot.com/2006/06/automatic-python-imports-with-autoimp.html,
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in the public domain.
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"""
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import sys
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class LazyModule: # pylint: disable=too-few-public-methods
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"""A lazy module proxy."""
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def __init__(self, modname):
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self.__dict__["__name__"] = modname
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self._set_mod(None)
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def _set_mod(self, mod):
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if mod is not None:
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self.__dict__ = mod.__dict__
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self.__dict__["_lazymod_mod"] = mod
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def _load_mod(self):
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__import__(self.__name__)
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self._set_mod(sys.modules[self.__name__])
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def __getattr__(self, name):
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if self.__dict__["_lazymod_mod"] is None:
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self._load_mod()
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mod = self.__dict__["_lazymod_mod"]
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if hasattr(mod, name):
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return getattr(mod, name)
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try:
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subname = f"{self.__name__}.{name}"
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__import__(subname)
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submod = getattr(mod, name) # pylint: disable=unused-variable
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except ImportError as exc:
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raise AttributeError(f"'module' object has no attribute {name!r}") from exc
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self.__dict__[name] = LazyModule(subname)
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return self.__dict__[name]
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