Index: base/task_scheduler/task_tracker.h |
diff --git a/base/task_scheduler/task_tracker.h b/base/task_scheduler/task_tracker.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..8c291991fc4e5361f8459ba47e03eed37859d058 |
--- /dev/null |
+++ b/base/task_scheduler/task_tracker.h |
@@ -0,0 +1,95 @@ |
+// 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_TASK_TRACKER_H_ |
+#define BASE_TASK_SCHEDULER_TASK_TRACKER_H_ |
+ |
+#include "base/base_export.h" |
+#include "base/callback_forward.h" |
+#include "base/macros.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "base/synchronization/condition_variable.h" |
+#include "base/task_scheduler/scheduler_lock.h" |
+#include "base/task_scheduler/task.h" |
+#include "base/task_scheduler/task_traits.h" |
+ |
+namespace base { |
+namespace internal { |
+ |
+// All tasks of the scheduler go through a TaskTracker when they are posted and |
+// when they are executed. The TaskTracker enforces shutdown semantics and takes |
+// care of tracing and profiling. This class is thread-safe. |
+class BASE_EXPORT TaskTracker { |
+ public: |
+ TaskTracker(); |
+ ~TaskTracker(); |
+ |
+ // Synchronously shuts down the task tracker. Once this is called, only tasks |
+ // posted with the BLOCK_SHUTDOWN behavior will be run. Returns when: |
+ // - All SKIP_ON_SHUTDOWN tasks that were already running have completed their |
+ // execution. |
+ // - All posted BLOCK_SHUTDOWN tasks have completed their execution. |
+ // This must only be called once. |
+ void Shutdown(); |
+ |
+ // Posts |task| by calling |post_task_callback| unless the current shutdown |
+ // state prevents that. A task forwarded to |post_task_callback| must be |
+ // handed off to this class' RunTask() when it is to be executed. |
gab
2016/03/09 21:53:25
s/handed off/handed back/
fdoray
2016/03/15 17:28:09
Done.
|
+ void PostTask(const Callback<void(scoped_ptr<Task>)>& post_task_callback, |
+ scoped_ptr<Task> task); |
+ |
+ // Runs |task| unless the current shutdown state prevents that. |task| must |
+ // have been successfully posted via PostTask() first. |
+ void RunTask(const Task* task); |
+ |
+ bool shutdown_completed() const { |
+ AutoSchedulerLock auto_lock(lock_); |
+ return shutdown_completed_; |
+ } |
+ |
+ bool is_shutting_down_for_testing() const { |
+ AutoSchedulerLock auto_lock(lock_); |
+ return is_shutting_down_; |
+ } |
+ |
+ private: |
+ // Called before a task with |shutdown_behavior| is handed off to |
+ // |post_task_callback| by PostTask(). Updates |num_tasks_blocking_shutdown_| |
+ // and returns true if the current shutdown state allows the task to be |
+ // posted. |
+ bool BeforePostTask(TaskShutdownBehavior shutdown_behavior); |
+ |
+ // Called before a task with |shutdown_behavior| is run by RunTask(). Updates |
+ // |num_tasks_blocking_shutdown_| and returns true if the current shutdown |
+ // state allows the task to be run. |
+ bool BeforeRunTask(TaskShutdownBehavior shutdown_behavior); |
+ |
+ // Called after a task with |shutdown_behavior| has been run by RunTask(). |
+ // Updates |num_tasks_blocking_shutdown_| and signals |cv_| when appropriate. |
+ void AfterRunTask(TaskShutdownBehavior shutdown_behavior); |
+ |
+ // Synchronizes access to all members. |
+ mutable SchedulerLock lock_; |
+ |
+ // Condition variable signaled when |num_tasks_blocking_shutdown_| reaches |
+ // zero while |is_shutting_down_|. |
+ scoped_ptr<ConditionVariable> cv_; |
+ |
+ // Number of tasks blocking shutdown. |
+ size_t num_tasks_blocking_shutdown_; |
+ |
+ // True when Shutdown() is waiting for tasks blocking shutdown to complete |
+ // their execution. |
+ bool is_shutting_down_; |
+ |
+ // True once Shutdown() has returned. No new task can be scheduled after this. |
+ bool shutdown_completed_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(TaskTracker); |
+}; |
+ |
+} // namespace internal |
+} // namespace base |
+ |
+#endif // BASE_TASK_SCHEDULER_TASK_TRACKER_H_ |