# Copyright 2021 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.

# ==============================================================================

"""Immutable mapping."""

import collections.abc

# WARNING: this class is used internally by extension types (tf.ExtensionType),

# and may be deleted if/when extension types transition to a different encoding

# in the future.

class ImmutableDict(collections.abc.Mapping):

"""Immutable `Mapping`."""

# Note: keys, items, values, get, __eq__, and __ne__ are implemented by

# the `Mapping` base class.

def __init__(self, *args, **kwargs):

self._dict = dict(*args, **kwargs)

def __getitem__(self, key):

return self._dict[key]

def __contains__(self, key):

return key in self._dict

def __iter__(self):

return iter(self._dict)

def __len__(self):

return len(self._dict)

def __repr__(self):

return f'ImmutableDict({self._dict})'

# This suppresses a warning that tf.nest would otherwise generate.

__supported_by_tf_nest__ = True