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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 | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ | |
6 #define BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ | |
7 | |
8 #include <stddef.h> | |
9 | |
10 #include <memory> | |
11 #include <queue> | |
12 #include <vector> | |
13 | |
14 #include "base/base_export.h" | |
15 #include "base/callback.h" | |
16 #include "base/macros.h" | |
17 #include "base/memory/ref_counted.h" | |
18 #include "base/task_scheduler/scheduler_lock.h" | |
19 #include "base/task_scheduler/sequence.h" | |
20 #include "base/task_scheduler/task.h" | |
21 #include "base/time/time.h" | |
22 | |
23 namespace base { | |
24 namespace internal { | |
25 | |
26 class PriorityQueue; | |
27 | |
28 // A DelayedTaskManager holds delayed Tasks until they become ripe for | |
29 // execution. When they become ripe for execution, it posts them to their | |
30 // associated Sequence and PriorityQueue. This class is thread-safe. | |
31 class BASE_EXPORT DelayedTaskManager { | |
32 public: | |
33 // |on_next_delayed_run_time_updated| is invoked when the next delayed run | |
34 // time is updated as a result of adding a delayed task to the manager. | |
35 explicit DelayedTaskManager(const Closure& on_next_delayed_run_time_updated); | |
36 ~DelayedTaskManager(); | |
37 | |
38 // Adds |task| to a queue of delayed tasks. The task will be inserted into | |
39 // |sequence| and |priority_queue| the first time that PostReadyTasks() is | |
40 // called while Now() is passed |task->delayed_run_time|. | |
41 void AddDelayedTask(std::unique_ptr<Task> task, | |
42 scoped_refptr<Sequence> sequence, | |
43 PriorityQueue* priority_queue); | |
44 | |
45 // Posts delayed tasks that are ripe for execution. | |
46 void PostReadyTasks(); | |
47 | |
48 // Returns the next time at which a delayed task will become ripe for | |
49 // execution, or a null TimeTicks if there are no pending delayed tasks. | |
50 TimeTicks GetNextDelayedRunTime() const; | |
51 | |
52 private: | |
53 struct DelayedTask; | |
54 struct DelayedTaskComparator { | |
55 bool operator()(const DelayedTask& left, const DelayedTask& right) const; | |
56 }; | |
57 | |
58 // Returns the current time. Can be overridden for tests. | |
59 virtual TimeTicks Now() const; | |
60 | |
61 const Closure on_next_delayed_run_time_updated_; | |
62 | |
63 // Synchronizes access to all members below. | |
64 mutable SchedulerLock lock_; | |
65 | |
66 // Priority queue of delayed tasks. The delayed task with the smallest | |
67 // |task->delayed_run_time| is in front of the priority queue. | |
68 using DelayedTaskQueue = std::priority_queue<DelayedTask, | |
69 std::vector<DelayedTask>, | |
70 DelayedTaskComparator>; | |
71 DelayedTaskQueue delayed_tasks_; | |
72 | |
73 // The index to assign to the next delayed task added to the manager. | |
74 size_t next_delayed_task_index_ = 0; | |
gab
2016/04/11 18:28:30
According to http://stackoverflow.com/questions/22
fdoray
2016/04/11 19:57:06
Done.
| |
75 | |
76 DISALLOW_COPY_AND_ASSIGN(DelayedTaskManager); | |
77 }; | |
78 | |
79 } // namespace internal | |
80 } // namespace base | |
81 | |
82 #endif // BASE_TASK_SCHEDULER_DELAYED_TASK_MANAGER_H_ | |
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