Fork the object_identity related class to Keras.

PiperOrigin-RevId: 339948109
Change-Id: Ia2612efa66b48ac5784d2a53cdeb0ce9001f4025

tensorflow/python/keras/BUILD

@@ -96,6 +96,7 @@ py_library(
         "//tensorflow/python/distribute:multi_worker_util",
         "//tensorflow/python/keras/engine:keras_tensor",
         "//tensorflow/python/keras/utils:control_flow_util",
+        "//tensorflow/python/keras/utils:object_identity",
         "//tensorflow/python/keras/utils:tf_contextlib",
         "//tensorflow/python/keras/utils:tf_inspect",
     ],

tensorflow/python/keras/backend.py

@@ -55,6 +55,7 @@ from tensorflow.python.framework import tensor_util
 from tensorflow.python.keras import backend_config
 from tensorflow.python.keras.engine import keras_tensor
 from tensorflow.python.keras.utils import control_flow_util
+from tensorflow.python.keras.utils import object_identity
 from tensorflow.python.keras.utils import tf_contextlib
 from tensorflow.python.keras.utils import tf_inspect
 from tensorflow.python.ops import array_ops
@@ -84,7 +85,6 @@ from tensorflow.python.training.tracking import util as tracking_util
 from tensorflow.python.util import dispatch
 from tensorflow.python.util import keras_deps
 from tensorflow.python.util import nest
-from tensorflow.python.util import object_identity
 from tensorflow.python.util.tf_export import keras_export
 from tensorflow.tools.docs import doc_controls
 

tensorflow/python/keras/engine/BUILD

@@ -159,6 +159,7 @@ py_library(
         "//tensorflow/python/keras/saving",
         "//tensorflow/python/keras/utils:generic_utils",
         "//tensorflow/python/keras/utils:layer_utils",
+        "//tensorflow/python/keras/utils:object_identity",
         "//tensorflow/python/keras/utils:tf_utils",
         "//tensorflow/python/keras/utils:version_utils",
         "//tensorflow/python/module",
@@ -206,6 +207,7 @@ py_library(
         "//tensorflow/python:dtypes",
         "//tensorflow/python:lib",
         "//tensorflow/python:tensor_spec",
+        "//tensorflow/python/keras/utils:object_identity",
         "@six_archive//:six",
     ],
 )

tensorflow/python/keras/engine/base_layer.py

@@ -62,6 +62,7 @@ from tensorflow.python.keras.mixed_precision import policy
 from tensorflow.python.keras.saving.saved_model import layer_serialization
 from tensorflow.python.keras.utils import generic_utils
 from tensorflow.python.keras.utils import layer_utils
+from tensorflow.python.keras.utils import object_identity
 from tensorflow.python.keras.utils import tf_inspect
 from tensorflow.python.keras.utils import tf_utils
 from tensorflow.python.keras.utils import version_utils
@@ -82,7 +83,6 @@ from tensorflow.python.training.tracking import data_structures
 from tensorflow.python.training.tracking import tracking
 from tensorflow.python.util import compat
 from tensorflow.python.util import nest
-from tensorflow.python.util import object_identity
 from tensorflow.python.util.tf_export import get_canonical_name_for_symbol
 from tensorflow.python.util.tf_export import keras_export
 from tensorflow.tools.docs import doc_controls

tensorflow/python/keras/engine/base_layer_v1.py

@@ -52,6 +52,7 @@ from tensorflow.python.keras.mixed_precision import policy
 from tensorflow.python.keras.saving.saved_model import layer_serialization
 from tensorflow.python.keras.utils import generic_utils
 from tensorflow.python.keras.utils import layer_utils
+from tensorflow.python.keras.utils import object_identity
 from tensorflow.python.keras.utils import tf_inspect
 from tensorflow.python.keras.utils import tf_utils
 # A module that only depends on `keras.layers` import these from here.
@@ -68,7 +69,6 @@ from tensorflow.python.training.tracking import base as trackable
 from tensorflow.python.training.tracking import data_structures
 from tensorflow.python.training.tracking import tracking
 from tensorflow.python.util import nest
-from tensorflow.python.util import object_identity
 from tensorflow.tools.docs import doc_controls
 
 

tensorflow/python/keras/engine/keras_tensor.py

@@ -25,11 +25,11 @@ from tensorflow.python.framework import sparse_tensor
 from tensorflow.python.framework import tensor_shape
 from tensorflow.python.framework import tensor_spec
 from tensorflow.python.framework import type_spec as type_spec_module
+from tensorflow.python.keras.utils import object_identity
 from tensorflow.python.ops import array_ops
 from tensorflow.python.ops.ragged import ragged_operators  # pylint: disable=unused-import
 from tensorflow.python.ops.ragged import ragged_tensor
 from tensorflow.python.util import nest
-from tensorflow.python.util import object_identity
 
 # pylint: disable=g-classes-have-attributes
 

tensorflow/python/keras/utils/BUILD

@@ -92,6 +92,7 @@ py_library(
     srcs = ["tf_utils.py"],
     srcs_version = "PY2AND3",
     deps = [
+        ":object_identity",
         "//tensorflow/python:composite_tensor",
         "//tensorflow/python:control_flow_ops",
         "//tensorflow/python:framework_ops",
@@ -210,6 +211,13 @@ py_library(
     ],
 )
 
+py_library(
+    name = "object_identity",
+    srcs = ["object_identity.py"],
+    srcs_version = "PY2AND3",
+    deps = [],
+)
+
 py_library(
     name = "tf_contextlib",
     srcs = ["tf_contextlib.py"],

tensorflow/python/keras/utils/object_identity.py

@@ -0,0 +1,247 @@
+"""Utilities for collecting objects based on "is" comparison."""
+# Copyright 2017 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.
+# ==============================================================================
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import collections.abc as collections_abc
+import weakref
+
+
+# LINT.IfChange
+class _ObjectIdentityWrapper(object):
+  """Wraps an object, mapping __eq__ on wrapper to "is" on wrapped.
+
+  Since __eq__ is based on object identity, it's safe to also define __hash__
+  based on object ids. This lets us add unhashable types like trackable
+  _ListWrapper objects to object-identity collections.
+  """
+
+  __slots__ = ["_wrapped", "__weakref__"]
+
+  def __init__(self, wrapped):
+    self._wrapped = wrapped
+
+  @property
+  def unwrapped(self):
+    return self._wrapped
+
+  def _assert_type(self, other):
+    if not isinstance(other, _ObjectIdentityWrapper):
+      raise TypeError("Cannot compare wrapped object with unwrapped object")
+
+  def __lt__(self, other):
+    self._assert_type(other)
+    return id(self._wrapped) < id(other._wrapped)  # pylint: disable=protected-access
+
+  def __gt__(self, other):
+    self._assert_type(other)
+    return id(self._wrapped) > id(other._wrapped)  # pylint: disable=protected-access
+
+  def __eq__(self, other):
+    if other is None:
+      return False
+    self._assert_type(other)
+    return self._wrapped is other._wrapped  # pylint: disable=protected-access
+
+  def __ne__(self, other):
+    return not self.__eq__(other)
+
+  def __hash__(self):
+    # Wrapper id() is also fine for weakrefs. In fact, we rely on
+    # id(weakref.ref(a)) == id(weakref.ref(a)) and weakref.ref(a) is
+    # weakref.ref(a) in _WeakObjectIdentityWrapper.
+    return id(self._wrapped)
+
+  def __repr__(self):
+    return "<{} wrapping {!r}>".format(type(self).__name__, self._wrapped)
+
+
+class _WeakObjectIdentityWrapper(_ObjectIdentityWrapper):
+
+  __slots__ = ()
+
+  def __init__(self, wrapped):
+    super(_WeakObjectIdentityWrapper, self).__init__(weakref.ref(wrapped))
+
+  @property
+  def unwrapped(self):
+    return self._wrapped()
+
+
+class Reference(_ObjectIdentityWrapper):
+  """Reference that refers an object.
+
+  ```python
+  x = [1]
+  y = [1]
+
+  x_ref1 = Reference(x)
+  x_ref2 = Reference(x)
+  y_ref2 = Reference(y)
+
+  print(x_ref1 == x_ref2)
+  ==> True
+
+  print(x_ref1 == y)
+  ==> False
+  ```
+  """
+
+  __slots__ = ()
+
+  # Disabling super class' unwrapped field.
+  unwrapped = property()
+
+  def deref(self):
+    """Returns the referenced object.
+
+    ```python
+    x_ref = Reference(x)
+    print(x is x_ref.deref())
+    ==> True
+    ```
+    """
+    return self._wrapped
+
+
+class ObjectIdentityDictionary(collections_abc.MutableMapping):
+  """A mutable mapping data structure which compares using "is".
+
+  This is necessary because we have trackable objects (_ListWrapper) which
+  have behavior identical to built-in Python lists (including being unhashable
+  and comparing based on the equality of their contents by default).
+  """
+
+  __slots__ = ["_storage"]
+
+  def __init__(self):
+    self._storage = {}
+
+  def _wrap_key(self, key):
+    return _ObjectIdentityWrapper(key)
+
+  def __getitem__(self, key):
+    return self._storage[self._wrap_key(key)]
+
+  def __setitem__(self, key, value):
+    self._storage[self._wrap_key(key)] = value
+
+  def __delitem__(self, key):
+    del self._storage[self._wrap_key(key)]
+
+  def __len__(self):
+    return len(self._storage)
+
+  def __iter__(self):
+    for key in self._storage:
+      yield key.unwrapped
+
+  def __repr__(self):
+    return "ObjectIdentityDictionary(%s)" % repr(self._storage)
+
+
+class ObjectIdentityWeakKeyDictionary(ObjectIdentityDictionary):
+  """Like weakref.WeakKeyDictionary, but compares objects with "is"."""
+
+  __slots__ = ["__weakref__"]
+
+  def _wrap_key(self, key):
+    return _WeakObjectIdentityWrapper(key)
+
+  def __len__(self):
+    # Iterate, discarding old weak refs
+    return len(list(self._storage))
+
+  def __iter__(self):
+    keys = self._storage.keys()
+    for key in keys:
+      unwrapped = key.unwrapped
+      if unwrapped is None:
+        del self[key]
+      else:
+        yield unwrapped
+
+
+class ObjectIdentitySet(collections_abc.MutableSet):
+  """Like the built-in set, but compares objects with "is"."""
+
+  __slots__ = ["_storage", "__weakref__"]
+
+  def __init__(self, *args):
+    self._storage = set(self._wrap_key(obj) for obj in list(*args))
+
+  @staticmethod
+  def _from_storage(storage):
+    result = ObjectIdentitySet()
+    result._storage = storage  # pylint: disable=protected-access
+    return result
+
+  def _wrap_key(self, key):
+    return _ObjectIdentityWrapper(key)
+
+  def __contains__(self, key):
+    return self._wrap_key(key) in self._storage
+
+  def discard(self, key):
+    self._storage.discard(self._wrap_key(key))
+
+  def add(self, key):
+    self._storage.add(self._wrap_key(key))
+
+  def update(self, items):
+    self._storage.update([self._wrap_key(item) for item in items])
+
+  def clear(self):
+    self._storage.clear()
+
+  def intersection(self, items):
+    return self._storage.intersection([self._wrap_key(item) for item in items])
+
+  def difference(self, items):
+    return ObjectIdentitySet._from_storage(
+        self._storage.difference([self._wrap_key(item) for item in items]))
+
+  def __len__(self):
+    return len(self._storage)
+
+  def __iter__(self):
+    keys = list(self._storage)
+    for key in keys:
+      yield key.unwrapped
+
+
+class ObjectIdentityWeakSet(ObjectIdentitySet):
+  """Like weakref.WeakSet, but compares objects with "is"."""
+
+  __slots__ = ()
+
+  def _wrap_key(self, key):
+    return _WeakObjectIdentityWrapper(key)
+
+  def __len__(self):
+    # Iterate, discarding old weak refs
+    return len([_ for _ in self])
+
+  def __iter__(self):
+    keys = list(self._storage)
+    for key in keys:
+      unwrapped = key.unwrapped
+      if unwrapped is None:
+        self.discard(key)
+      else:
+        yield unwrapped
+# LINT.ThenChange(//tensorflow/python/util/object_identity.py)

tensorflow/python/keras/utils/tf_utils.py

@@ -32,13 +32,13 @@ from tensorflow.python.framework import tensor_util
 from tensorflow.python.framework import type_spec
 from tensorflow.python.keras import backend as K
 from tensorflow.python.keras.engine import keras_tensor
+from tensorflow.python.keras.utils import object_identity
 from tensorflow.python.keras.utils import tf_contextlib
 from tensorflow.python.ops import math_ops
 from tensorflow.python.ops import variables
 from tensorflow.python.ops.ragged import ragged_tensor
 from tensorflow.python.ops.ragged import ragged_tensor_value
 from tensorflow.python.util import nest
-from tensorflow.python.util import object_identity
 
 
 def is_tensor_or_tensor_list(v):

tensorflow/python/util/object_identity.py

@@ -22,6 +22,7 @@ import weakref
 from tensorflow.python.util.compat import collections_abc
 
 
+# LINT.IfChange
 class _ObjectIdentityWrapper(object):
   """Wraps an object, mapping __eq__ on wrapper to "is" on wrapped.
 
@@ -244,3 +245,4 @@ class ObjectIdentityWeakSet(ObjectIdentitySet):
         self.discard(key)
       else:
         yield unwrapped
+# LINT.ThenChange(//tensorflow/python/keras/utils/object_identity.py)