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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ | 5 #ifndef BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ |
6 #define BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ | 6 #define BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ |
7 | 7 |
8 #include <memory> | 8 #include <memory> |
9 #include <utility> | |
10 #include <vector> | |
9 | 11 |
10 #include "base/base_export.h" | 12 #include "base/base_export.h" |
11 #include "base/callback_forward.h" | 13 #include "base/callback.h" |
12 #include "base/macros.h" | 14 #include "base/macros.h" |
15 #include "base/memory/ptr_util.h" | |
13 #include "base/memory/ref_counted.h" | 16 #include "base/memory/ref_counted.h" |
17 #include "base/synchronization/atomic_flag.h" | |
18 #include "base/task_scheduler/scheduler_lock.h" | |
19 #include "base/time/default_tick_clock.h" | |
20 #include "base/time/tick_clock.h" | |
14 | 21 |
15 namespace base { | 22 namespace base { |
16 | 23 |
17 class TaskRunner; | 24 class TaskRunner; |
18 | 25 |
19 namespace internal { | 26 namespace internal { |
20 | 27 |
21 struct Task; | 28 struct Task; |
22 | 29 |
23 // The DelayedTaskManager forwards tasks to various scheduler components when | 30 // The DelayedTaskManager forwards tasks to post task callbacks when they become |
24 // they become ripe for execution. This class is thread-safe. | 31 // ripe for execution. Tasks are not forwarded before Start() is called. This |
32 // class is thread-safe. | |
25 class BASE_EXPORT DelayedTaskManager { | 33 class BASE_EXPORT DelayedTaskManager { |
26 public: | 34 public: |
27 // Posts |task| for execution immediately. | 35 // Posts |task| for execution immediately. |
28 using PostTaskNowCallback = Callback<void(std::unique_ptr<Task> task)>; | 36 using PostTaskNowCallback = OnceCallback<void(std::unique_ptr<Task> task)>; |
29 | 37 |
38 DelayedTaskManager( | |
gab
2017/04/19 18:59:17
Add a comment that |tick_clock| can be specified f
fdoray
2017/04/20 12:08:52
Done.
| |
39 std::unique_ptr<TickClock> tick_clock = MakeUnique<DefaultTickClock>()); | |
40 ~DelayedTaskManager(); | |
41 | |
42 // Starts the delayed task manager, allowing past and future tasks to be | |
43 // forwarded to their callbacks as they become ripe for execution. | |
30 // |service_thread_task_runner| posts tasks to the TaskScheduler service | 44 // |service_thread_task_runner| posts tasks to the TaskScheduler service |
31 // thread. | 45 // thread. |
32 explicit DelayedTaskManager( | 46 void Start(scoped_refptr<TaskRunner> service_thread_task_runner); |
33 scoped_refptr<TaskRunner> service_thread_task_runner); | |
34 ~DelayedTaskManager(); | |
35 | 47 |
36 // Calls |post_task_now_callback| with |task| when |task| is ripe for | 48 // Schedules a call to |post_task_now_callback| with |task| as argument when |
37 // execution. | 49 // |task| is ripe for execution and Start() has been called. |
38 void AddDelayedTask(std::unique_ptr<Task> task, | 50 void AddDelayedTask(std::unique_ptr<Task> task, |
39 const PostTaskNowCallback& post_task_now_callback); | 51 PostTaskNowCallback post_task_now_callback); |
40 | 52 |
41 private: | 53 private: |
42 const scoped_refptr<TaskRunner> service_thread_task_runner_; | 54 // Schedules a call to |post_task_now_callback| with |task| as argument when |
55 // |task| is ripe for execution. Start() must have been called before this. | |
56 void AddDelayedTaskNow(std::unique_ptr<Task> task, | |
57 PostTaskNowCallback post_task_now_callback); | |
58 | |
59 const std::unique_ptr<TickClock> tick_clock_; | |
60 | |
61 AtomicFlag started_; | |
62 | |
63 // Synchronizes access to all members below before |started_| is set. Once | |
64 // |started_| is set: | |
65 // - |service_thread_task_runner| stays constant, so it can be read without | |
66 // holding the lock. | |
67 // - |tasks_added_before_start_| shouldn't be accessed anymore. | |
68 SchedulerLock lock_; | |
69 | |
70 scoped_refptr<TaskRunner> service_thread_task_runner_; | |
71 std::vector<std::pair<std::unique_ptr<Task>, PostTaskNowCallback>> | |
72 tasks_added_before_start_; | |
43 | 73 |
44 DISALLOW_COPY_AND_ASSIGN(DelayedTaskManager); | 74 DISALLOW_COPY_AND_ASSIGN(DelayedTaskManager); |
45 }; | 75 }; |
46 | 76 |
47 } // namespace internal | 77 } // namespace internal |
48 } // namespace base | 78 } // namespace base |
49 | 79 |
50 #endif // BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ | 80 #endif // BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ |
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