Index: base/task_scheduler/worker_thread.h |
diff --git a/base/task_scheduler/worker_thread.h b/base/task_scheduler/worker_thread.h |
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+// Copyright 2016 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_TASK_SCHEDULER_WORKER_THREAD_H_ |
+#define BASE_TASK_SCHEDULER_WORKER_THREAD_H_ |
+ |
+#include "base/base_export.h" |
+#include "base/callback_forward.h" |
+#include "base/macros.h" |
+#include "base/memory/ref_counted.h" |
+#include "base/single_thread_task_runner.h" |
+#include "base/synchronization/waitable_event.h" |
+#include "base/task_scheduler/priority_queue.h" |
+#include "base/task_scheduler/sequence.h" |
+#include "base/task_scheduler/task_traits.h" |
+#include "base/threading/platform_thread.h" |
+ |
+namespace base { |
+namespace task_scheduler { |
+ |
+class DelayedTaskManager; |
+class ShutdownManager; |
+ |
+// A thread that runs tasks from a shared and a single-threaded priority queue. |
+// Unless otherwise noted, all public methods of this class are thread-safe. |
+class BASE_EXPORT WorkerThread : public PlatformThread::Delegate { |
+ public: |
+ // Callback to reinsert |sequence| in the appropriate priority queue after one |
+ // of its tasks has been executed. |worker_thread| is the worker thread that |
+ // invokes the callback. |
+ using ReinsertSequenceCallback = |
+ Callback<void(scoped_refptr<Sequence> sequence, |
+ const WorkerThread* worker_thread)>; |
+ |
+ // Callback invoked when the worker thread becomes idle. |worker_thread| is |
+ // the worker thread that invokes the callback. |
+ using BecomesIdleCallback = Callback<void(WorkerThread* worker_thread)>; |
+ |
+ // Creates a worker thread that runs tasks from a single-thread priority queue |
+ // and from |shared_priority_queue| with |thread_priority|. |
+ // |reinsert_sequence_callback| is invoked to reinsert a sequence in the |
+ // appropriate priority queue after one of its tasks has been executed. |
+ // |delayed_task_manager| is used to handle delayed tasks. |shutdown_manager| |
+ // is used to handle shutdown behavior of tasks. |
+ static scoped_ptr<WorkerThread> CreateWorkerThread( |
+ ThreadPriority thread_priority, |
+ PriorityQueue* shared_priority_queue, |
+ const ReinsertSequenceCallback& reinsert_sequence_callback, |
+ const BecomesIdleCallback& becomes_idle_callback, |
+ DelayedTaskManager* delayed_task_manager, |
+ ShutdownManager* shutdown_manager); |
+ |
+ ~WorkerThread() override; |
+ |
+ // Wakes up the worker thread. Soon after this is called, the thread starts |
+ // running tasks from its priority queue. It continues to run tasks until its |
+ // priority queue is empty. Has no effect if the worker thread is already |
+ // running tasks. |
+ void WakeUp(); |
+ |
+ // Returns a SingleThreadTaskRunner whose PostTask invocations will result in |
+ // scheduling tasks on this worker thread with traits |traits|. |
+ scoped_refptr<SingleThreadTaskRunner> CreateTaskRunnerWithTraits( |
+ const TaskTraits& traits, |
+ ExecutionMode execution_mode); |
+ |
+ // Returns true if the worker thread has single-threaded tasks (running or |
+ // pending). Use a memory barrier before calling this to avoid getting a stale |
+ // result. The returned result can be invalidated at any time by single- |
+ // threaded tasks being posted or run. |
+ bool HasSingleThreadedTasks() const; |
robliao
2016/02/11 21:56:27
Since we're claiming this is thread safe, maybe we
fdoray
2016/02/12 04:16:20
Done.
|
+ |
+ // Waits until the thread exits. This must only be called after shutdown is |
+ // complete (shutdown_manager_->shutdown_completed() returns true). This |
+ // method is not thread-safe. |
fdoray
2016/02/11 17:30:34
This can only be called once per WorkerThread.
robliao
2016/02/11 21:56:27
We should be able to assert this.
fdoray
2016/02/12 04:16:20
Done. I added a DCHECK, which is unfortunately not
|
+ void JoinForTesting(); |
+ |
+ const PriorityQueue* shared_priority_queue() const { |
+ return shared_priority_queue_; |
+ } |
+ |
+ private: |
+ WorkerThread(ThreadPriority thread_priority, |
+ PriorityQueue* shared_priority_queue, |
+ const ReinsertSequenceCallback& reinsert_sequence_callback, |
+ const BecomesIdleCallback& becomes_idle_callback, |
+ DelayedTaskManager* delayed_task_manager, |
+ ShutdownManager* shutdown_manager); |
+ |
+ // Returns true if a thread has been successfully created by the constructor. |
+ bool IsValid() const; |
+ |
+ // Extracts the sequence with the highest priority from |
+ // |shared_priority_queue_| or |single_thread_priority_queue_|. |
+ scoped_refptr<Sequence> GetWork(); |
+ |
+ // Reinserts |sequence| in |single_thread_priority_queue_|. |
+ void ReinsertSequenceInSingleThreadPriorityQueue( |
+ scoped_refptr<Sequence> sequence); |
+ |
+ // Waits until either |wakeup_event_| is signaled or a task from |
+ // |delayed_task_manager_| becomes ready for execution. |
+ void WaitUntilWorkIsAvailable(); |
+ |
+ // PlatformThread::Delegate: |
+ void ThreadMain() override; |
+ |
+ // Platform thread managed by this object. |
+ PlatformThreadHandle thread_handle_; |
+ |
+ // Event signaled to wake up the thread. |
+ mutable WaitableEvent wakeup_event_; |
+ |
+ // True when the worker thread is running a single-threaded task. |
+ bool is_running_single_threaded_task_; |
+ |
+ // The single-threaded priority queue from which the worker thread gets work. |
+ // Tasks posted to a SINGLE_THREADED* task runner returned by this |
+ // WorkerThread end up in this priority queue. |
+ PriorityQueue single_thread_priority_queue_; |
+ |
+ // The shared priority queue from which the worker thread gets work. |
+ PriorityQueue* const shared_priority_queue_; |
+ |
+ const ReinsertSequenceCallback reinsert_sequence_callback_; |
+ |
+ const BecomesIdleCallback becomes_idle_callback_; |
+ |
+ DelayedTaskManager* const delayed_task_manager_; |
+ |
+ ShutdownManager* const shutdown_manager_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(WorkerThread); |
+}; |
+ |
+} // namespace task_scheduler |
+} // namespace base |
+ |
+#endif // BASE_TASK_SCHEDULER_WORKER_THREAD_H_ |