OLD | NEW |
| (Empty) |
1 // Copyright 2013 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 NET_QUIC_QUIC_ALARM_H_ | |
6 #define NET_QUIC_QUIC_ALARM_H_ | |
7 | |
8 #include "base/memory/scoped_ptr.h" | |
9 #include "net/base/net_export.h" | |
10 #include "net/quic/quic_time.h" | |
11 | |
12 namespace net { | |
13 | |
14 // Abstract class which represents an alarm which will go off at a | |
15 // scheduled time, and execute the |OnAlarm| method of the delegate. | |
16 // An alarm may be cancelled, in which case it may or may not be | |
17 // removed from the underlying scheduling system, but in either case | |
18 // the task will not be executed. | |
19 class NET_EXPORT_PRIVATE QuicAlarm { | |
20 public: | |
21 class NET_EXPORT_PRIVATE Delegate { | |
22 public: | |
23 virtual ~Delegate() {} | |
24 | |
25 // Invoked when the alarm fires. If the return value is not | |
26 // infinite, then the alarm will be rescheduled at the | |
27 // specified time. | |
28 virtual QuicTime OnAlarm() = 0; | |
29 }; | |
30 | |
31 explicit QuicAlarm(Delegate* delegate); | |
32 virtual ~QuicAlarm(); | |
33 | |
34 // Sets the alarm to fire at |deadline|. Must not be called while | |
35 // the alarm is set. To reschedule an alarm, call Cancel() first, | |
36 // then Set(). | |
37 void Set(QuicTime deadline); | |
38 | |
39 // Cancels the alarm. May be called repeatedly. Does not | |
40 // guarantee that the underlying scheduling system will remove | |
41 // the alarm's associated task, but guarantees that the | |
42 // delegates OnAlarm method will not be called. | |
43 void Cancel(); | |
44 | |
45 // Cancels and sets the alarm if the |deadline| is farther from the current | |
46 // deadline than |granularity|, and otherwise does nothing. If |deadline| is | |
47 // not initialized, the alarm is cancelled. | |
48 void Update(QuicTime deadline, QuicTime::Delta granularity); | |
49 | |
50 bool IsSet() const; | |
51 | |
52 QuicTime deadline() const { return deadline_; } | |
53 | |
54 protected: | |
55 // Subclasses implement this method to perform the platform-specific | |
56 // scheduling of the alarm. Is called from Set() or Fire(), after the | |
57 // deadline has been updated. | |
58 virtual void SetImpl() = 0; | |
59 | |
60 // Subclasses implement this method to perform the platform-specific | |
61 // cancelation of the alarm. | |
62 virtual void CancelImpl() = 0; | |
63 | |
64 // Called by subclasses when the alarm fires. Invokes the | |
65 // delegates |OnAlarm| if a delegate is set, and if the deadline | |
66 // has been exceeded. Implementations which do not remove the | |
67 // alarm from the underlying scheduler on Cancel() may need to handle | |
68 // the situation where the task executes before the deadline has been | |
69 // reached, in which case they need to reschedule the task and must not | |
70 // call invoke this method. | |
71 void Fire(); | |
72 | |
73 private: | |
74 scoped_ptr<Delegate> delegate_; | |
75 QuicTime deadline_; | |
76 | |
77 DISALLOW_COPY_AND_ASSIGN(QuicAlarm); | |
78 }; | |
79 | |
80 } // namespace net | |
81 | |
82 #endif // NET_QUIC_QUIC_ALARM_H_ | |
OLD | NEW |