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