wehub-resource-sync
84 lines
2.7 KiB
Python
84 lines
2.7 KiB
Python
# Copyright 2019 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""Cancellation support for eager execution."""
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import functools
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import threading
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from typing import Any, Callable, Optional
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from tensorflow.python import pywrap_tfe
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class CancellationManager:
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"""A mechanism for cancelling blocking computation."""
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__slots__ = ["_impl"]
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def __init__(self):
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self._impl = pywrap_tfe.TFE_NewCancellationManager()
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@property
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def is_cancelled(self):
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"""Returns `True` if `CancellationManager.start_cancel` has been called."""
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return pywrap_tfe.TFE_CancellationManagerIsCancelled(self._impl)
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def start_cancel(self):
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"""Cancels blocking operations that have been registered with this object."""
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pywrap_tfe.TFE_CancellationManagerStartCancel(self._impl)
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def get_cancelable_function(
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self, concrete_function: Callable[..., Any]
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) -> Callable[..., Any]:
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"""Wraps a ConcreteFunction to execute within this cancellation manager's context.
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Args:
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concrete_function: The ConcreteFunction to wrap.
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Returns:
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A callable that executes the concrete_function under this cancellation
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context.
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"""
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@functools.wraps(concrete_function)
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def cancellable(*args, **kwargs):
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with CancellationManagerContext(self):
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return concrete_function(*args, **kwargs)
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return cancellable
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_active_context = threading.local()
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def context() -> Optional[CancellationManager]:
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"""Returns the CancellationManager active in the current thread, or None."""
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stack = getattr(_active_context, "manager_stack", None)
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return stack[-1] if stack else None
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class CancellationManagerContext:
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"""A Python context for wrapping a cancellable ConcreteFunction."""
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def __init__(self, cancellation_manager):
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self._cancellation_manager = cancellation_manager
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def __enter__(self):
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if not hasattr(_active_context, "manager_stack"):
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_active_context.manager_stack = []
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_active_context.manager_stack.append(self._cancellation_manager)
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def __exit__(self, exc_type, exc_value, exc_tb):
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_active_context.manager_stack.pop()
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