# Copyright 2020 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.
# ==============================================================================
"""Context for building SavedModel."""

import contextlib
import threading


class SaveContext(threading.local):
  """A context for building a graph of SavedModel."""

  def __init__(self):
    super(SaveContext, self).__init__()
    self._in_save_context = False
    self._options = None

  def options(self):
    if not self.in_save_context():
      raise ValueError("Not in a SaveContext.")
    return self._options

  def enter_save_context(self, options):
    self._in_save_context = True
    self._options = options

  def exit_save_context(self):
    self._in_save_context = False
    self._options = None

  def in_save_context(self):
    return self._in_save_context

_save_context = SaveContext()


@contextlib.contextmanager
def save_context(options):
  if in_save_context():
    raise ValueError("Already in a SaveContext.")
  _save_context.enter_save_context(options)
  try:
    yield
  finally:
    _save_context.exit_save_context()


def in_save_context():
  """Returns whether under a save context."""
  return _save_context.in_save_context()


def get_save_options():
  """Returns the save options if under a save context."""
  return _save_context.options()