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1 // Copyright 2017 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 CHROMECAST_BASE_ALARM_MANAGER_H_ | |
6 #define CHROMECAST_BASE_ALARM_MANAGER_H_ | |
7 | |
8 #include <map> | |
halliwell
2017/02/22 19:09:15
unused?
ryanchung
2017/02/22 19:39:39
Done.
| |
9 #include <queue> | |
10 #include <vector> | |
11 | |
12 #include "base/callback_forward.h" | |
13 #include "base/macros.h" | |
14 #include "base/memory/ref_counted.h" | |
15 #include "base/memory/weak_ptr.h" | |
16 #include "base/threading/thread.h" | |
17 #include "base/time/clock.h" | |
18 #include "base/timer/timer.h" | |
halliwell
2017/02/22 19:09:15
nit, can just forward-declare for things held in u
ryanchung
2017/02/22 19:39:39
Done. thx.
| |
19 | |
20 namespace chromecast { | |
21 | |
22 // Alarm manager allows setting a task for wall clock time rather than for an | |
23 // elapsed amount of time. This is different from using long PostDelayedTasks | |
24 // that are sensitive to time changes, clock drift, and other factors. | |
25 // | |
26 // Alarm manager polls the wall clock time every 5 seconds. If the clock is | |
27 // equal or past the requested time, the alarm will fire. | |
28 // | |
29 // Any thread can add or remove alarms. The alarm will be fired on the original | |
30 // thread used to set the alarm. | |
31 // | |
32 // When an alarm is added to the alarm manager, the task is guaranteed to not | |
33 // run before the clock passes the requested time. The task may not run even if | |
34 // it is past the requested time if the software is suspended. However, once | |
35 // woken up, the event will fire within 5 seconds if the target time has passed. | |
36 class AlarmManager { | |
37 public: | |
38 // Construct and start the alarm manager. | |
39 AlarmManager(); | |
40 ~AlarmManager(); | |
41 | |
42 // For testing only. Allows setting a fake clock and using a custom task | |
43 // runner. | |
44 AlarmManager(std::unique_ptr<base::Clock> clock, | |
45 scoped_refptr<base::SingleThreadTaskRunner> task_runner); | |
46 | |
47 // Add an alarm. | |
48 // |task| will be executed at around |time|. | |
49 void PostAlarmTask(const base::Closure& task, base::Time time); | |
50 | |
51 private: | |
52 class AlarmInfo { | |
53 public: | |
54 AlarmInfo(const base::Closure& task, | |
55 base::Time time, | |
56 scoped_refptr<base::SingleThreadTaskRunner> task_runner); | |
57 ~AlarmInfo(); | |
58 | |
59 const base::Closure task() const { return task_; } | |
60 base::Time time() const { return time_; } | |
61 scoped_refptr<base::SingleThreadTaskRunner> task_runner() const { | |
62 return task_runner_; | |
63 } | |
64 | |
65 private: | |
66 const base::Closure task_; | |
67 const base::Time time_; | |
68 const scoped_refptr<base::SingleThreadTaskRunner> task_runner_; | |
69 DISALLOW_COPY_AND_ASSIGN(AlarmInfo); | |
70 }; | |
71 | |
72 // Check if an alarm should fire. | |
73 void CheckAlarm(); | |
74 // Add the alarm to the queue. | |
75 void AddAlarm(const base::Closure& task, | |
76 base::Time time, | |
77 scoped_refptr<base::SingleThreadTaskRunner> task_runner); | |
78 | |
79 // Ordering alarms by earliest time. | |
80 struct alarm_compare | |
81 : public std::binary_function<std::unique_ptr<AlarmInfo>&, | |
82 std::unique_ptr<AlarmInfo>&, | |
83 bool> { | |
84 bool operator()(const std::unique_ptr<AlarmInfo>& lhs, | |
85 const std::unique_ptr<AlarmInfo>& rhs) const { | |
86 return lhs->time() > rhs->time(); | |
87 } | |
88 }; | |
89 | |
90 // Store a list of the alarms to fire at a certain time. | |
91 std::priority_queue<std::unique_ptr<AlarmInfo>, | |
92 std::vector<std::unique_ptr<AlarmInfo>>, | |
93 alarm_compare> | |
94 next_alarm_; | |
95 | |
96 // Poller for wall clock time. | |
97 std::unique_ptr<base::Clock> clock_; | |
98 std::unique_ptr<base::Timer> clock_tick_timer_; | |
99 std::unique_ptr<base::Thread> alarm_thread_; | |
100 scoped_refptr<base::SingleThreadTaskRunner> task_runner_; | |
101 | |
102 base::WeakPtrFactory<AlarmManager> weak_factory_; | |
103 | |
104 DISALLOW_COPY_AND_ASSIGN(AlarmManager); | |
105 }; | |
106 | |
107 } // namespace chromecast | |
108 | |
109 #endif // CHROMECAST_BASE_ALARM_MANAGER_H_ | |
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