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44 lines
1.5 KiB
Python
44 lines
1.5 KiB
Python
# Code copied from https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/util/lazy_loader.py
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import importlib
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import types
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class LazyLoader(types.ModuleType):
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"""Lazily import a module, mainly to avoid pulling in large dependencies.
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This allows them to only be loaded when they are used.
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"""
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def __init__(self, local_name, parent_module_globals, name):
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self._local_name = local_name
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self._parent_module_globals = parent_module_globals
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super(LazyLoader, self).__init__(name)
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def _load(self):
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"""Load the module and insert it into the parent's globals."""
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# Import the target module and insert it into the parent's namespace
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try:
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module = importlib.import_module(self.__name__)
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except ModuleNotFoundError as e:
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raise ModuleNotFoundError(
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f"Lazy module loader cannot find module named `{self.__name__}`. Please run `pip install {self.__name__}`."
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) from e
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self._parent_module_globals[self._local_name] = module
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# Update this object's dict so that if someone keeps a reference to the
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# LazyLoader, lookups are efficient (__getattr__ is only called on lookups
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# that fail).
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self.__dict__.update(module.__dict__)
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return module
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def __getattr__(self, item):
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module = self._load()
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return getattr(module, item)
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def __dir__(self):
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module = self._load()
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return dir(module)
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