// Copyright 2014 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_DEBUG_TASK_ANNOTATOR_H_
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#define BASE_DEBUG_TASK_ANNOTATOR_H_
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#include <stdint.h>
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#include "base/base_export.h"
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#include "base/macros.h"
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namespace base {
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struct PendingTask;
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namespace debug {
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// Implements common debug annotations for posted tasks. This includes data
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// such as task origins, queueing durations and memory usage.
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class BASE_EXPORT TaskAnnotator {
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public:
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class ObserverForTesting {
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public:
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virtual ~ObserverForTesting() = default;
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// Invoked just before RunTask() in the scope in which the task is about to
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// be executed.
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virtual void BeforeRunTask(const PendingTask* pending_task) = 0;
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};
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TaskAnnotator();
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~TaskAnnotator();
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// Called to indicate that a task is about to be queued to run in the future,
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// giving one last chance for this TaskAnnotator to add metadata to
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// |pending_task| before it is moved into the queue. |queue_function| is used
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// as the trace flow event name. |queue_function| can be null if the caller
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// doesn't want trace flow events logged to toplevel.flow.
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void WillQueueTask(const char* queue_function, PendingTask* pending_task);
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// Run a previously queued task. |queue_function| should match what was
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// passed into |DidQueueTask| for this task.
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void RunTask(const char* queue_function, PendingTask* pending_task);
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// Creates a process-wide unique ID to represent this task in trace events.
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// This will be mangled with a Process ID hash to reduce the likelyhood of
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// colliding with TaskAnnotator pointers on other processes. Callers may use
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// this when generating their own flow events (i.e. when passing
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// |queue_function == nullptr| in above methods).
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uint64_t GetTaskTraceID(const PendingTask& task) const;
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private:
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friend class TaskAnnotatorBacktraceIntegrationTest;
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// Registers an ObserverForTesting that will be invoked by all TaskAnnotators'
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// RunTask(). This registration and the implementation of BeforeRunTask() are
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// responsible to ensure thread-safety.
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static void RegisterObserverForTesting(ObserverForTesting* observer);
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static void ClearObserverForTesting();
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DISALLOW_COPY_AND_ASSIGN(TaskAnnotator);
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};
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} // namespace debug
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} // namespace base
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#endif // BASE_DEBUG_TASK_ANNOTATOR_H_
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