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| 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_ | |
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