1 // Copyright 2011 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 CC_SCHEDULER_DELAY_BASED_TIME_SOURCE_H_ 6 #define CC_SCHEDULER_DELAY_BASED_TIME_SOURCE_H_ 7 8 #include <string> 9 10 #include "base/memory/weak_ptr.h" 11 #include "base/values.h" 12 #include "cc/base/cc_export.h" 13 14 namespace base { class SingleThreadTaskRunner; } 15 16 namespace cc { 17 18 class CC_EXPORT TimeSourceClient { 19 public: 20 virtual void OnTimerTick() = 0; 21 22 protected: 23 virtual ~TimeSourceClient() {} 24 }; 25 26 // This timer implements a time source that achieves the specified interval 27 // in face of millisecond-precision delayed callbacks and random queueing 28 // delays. DelayBasedTimeSource uses base::TimeTicks::Now as its timebase. 29 class CC_EXPORT DelayBasedTimeSource 30 : public base::RefCounted<DelayBasedTimeSource> { 31 public: 32 static scoped_refptr<DelayBasedTimeSource> Create( 33 base::TimeDelta interval, base::SingleThreadTaskRunner* task_runner); 34 35 virtual void SetClient(TimeSourceClient* client); 36 37 // TimeSource implementation 38 virtual void SetTimebaseAndInterval(base::TimeTicks timebase, 39 base::TimeDelta interval); 40 41 virtual base::TimeTicks SetActive(bool active); 42 virtual bool Active() const; 43 44 // Get the last and next tick times. NextTickTime() returns null when 45 // inactive. 46 virtual base::TimeTicks LastTickTime() const; 47 virtual base::TimeTicks NextTickTime() const; 48 49 // Virtual for testing. 50 virtual base::TimeTicks Now() const; 51 52 virtual scoped_ptr<base::Value> AsValue() const; 53 54 protected: 55 DelayBasedTimeSource(base::TimeDelta interval, 56 base::SingleThreadTaskRunner* task_runner); 57 virtual ~DelayBasedTimeSource(); 58 59 virtual std::string TypeString() const; 60 61 base::TimeTicks NextTickTarget(base::TimeTicks now); 62 void PostNextTickTask(base::TimeTicks now); 63 void OnTimerFired(); 64 65 struct Parameters { 66 Parameters(base::TimeDelta interval, base::TimeTicks tick_target) 67 : interval(interval), tick_target(tick_target) {} 68 base::TimeDelta interval; 69 base::TimeTicks tick_target; 70 }; 71 72 TimeSourceClient* client_; 73 base::TimeTicks last_tick_time_; 74 75 // current_parameters_ should only be written by PostNextTickTask. 76 // next_parameters_ will take effect on the next call to PostNextTickTask. 77 // Maintaining a pending set of parameters allows NextTickTime() to always 78 // reflect the actual time we expect OnTimerFired to be called. 79 Parameters current_parameters_; 80 Parameters next_parameters_; 81 82 bool active_; 83 84 base::SingleThreadTaskRunner* task_runner_; 85 base::WeakPtrFactory<DelayBasedTimeSource> weak_factory_; 86 87 private: 88 friend class base::RefCounted<DelayBasedTimeSource>; 89 DISALLOW_COPY_AND_ASSIGN(DelayBasedTimeSource); 90 }; 91 92 // DelayBasedTimeSource uses base::TimeTicks::HighResNow as its timebase. 93 class DelayBasedTimeSourceHighRes : public DelayBasedTimeSource { 94 public: 95 static scoped_refptr<DelayBasedTimeSourceHighRes> Create( 96 base::TimeDelta interval, base::SingleThreadTaskRunner* task_runner); 97 98 virtual base::TimeTicks Now() const OVERRIDE; 99 100 protected: 101 DelayBasedTimeSourceHighRes(base::TimeDelta interval, 102 base::SingleThreadTaskRunner* task_runner); 103 virtual ~DelayBasedTimeSourceHighRes(); 104 105 virtual std::string TypeString() const OVERRIDE; 106 107 private: 108 DISALLOW_COPY_AND_ASSIGN(DelayBasedTimeSourceHighRes); 109 }; 110 111 } // namespace cc 112 113 #endif // CC_SCHEDULER_DELAY_BASED_TIME_SOURCE_H_ 114
