68 lines
2.3 KiB
Python
68 lines
2.3 KiB
Python
# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
# ==============================================================================
|
|
|
|
"""A LazyLoader class."""
|
|
|
|
from __future__ import absolute_import
|
|
from __future__ import division
|
|
from __future__ import print_function
|
|
|
|
import importlib
|
|
import types
|
|
from tensorflow.python.platform import tf_logging as logging
|
|
|
|
|
|
class LazyLoader(types.ModuleType):
|
|
"""Lazily import a module, mainly to avoid pulling in large dependencies.
|
|
|
|
`contrib`, and `ffmpeg` are examples of modules that are large and not always
|
|
needed, and this allows them to only be loaded when they are used.
|
|
"""
|
|
|
|
# The lint error here is incorrect.
|
|
def __init__(self, local_name, parent_module_globals, name, warning=None): # pylint: disable=super-on-old-class
|
|
self._local_name = local_name
|
|
self._parent_module_globals = parent_module_globals
|
|
self._warning = warning
|
|
|
|
super(LazyLoader, self).__init__(name)
|
|
|
|
def _load(self):
|
|
"""Load the module and insert it into the parent's globals."""
|
|
# Import the target module and insert it into the parent's namespace
|
|
module = importlib.import_module(self.__name__)
|
|
self._parent_module_globals[self._local_name] = module
|
|
|
|
# Emit a warning if one was specified
|
|
if self._warning:
|
|
logging.warning(self._warning)
|
|
# Make sure to only warn once.
|
|
self._warning = None
|
|
|
|
# Update this object's dict so that if someone keeps a reference to the
|
|
# LazyLoader, lookups are efficient (__getattr__ is only called on lookups
|
|
# that fail).
|
|
self.__dict__.update(module.__dict__)
|
|
|
|
return module
|
|
|
|
def __getattr__(self, item):
|
|
module = self._load()
|
|
return getattr(module, item)
|
|
|
|
def __dir__(self):
|
|
module = self._load()
|
|
return dir(module)
|