cc/scheduler/time_source.h

   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_TIME_SOURCE_H_
   6 #define CC_SCHEDULER_TIME_SOURCE_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "base/time/time.h"
  10 #include "cc/base/cc_export.h"
  11
  12 namespace cc {
  13
  14 class CC_EXPORT TimeSourceClient {
  15  public:
  16   virtual void OnTimerTick() = 0;
  17
  18  protected:
  19   virtual ~TimeSourceClient() {}
  20 };
  21
  22 // An generic interface for getting a reliably-ticking timesource of
  23 // a specified rate.
  24 //
  25 // Be sure to call SetActive(false) before releasing your reference to the
  26 // timer, or it will keep on ticking!
  27 class CC_EXPORT TimeSource : public base::RefCounted<TimeSource> {
  28  public:
  29   virtual void SetClient(TimeSourceClient* client) = 0;
  30
  31   // If transitioning from not active to active, SetActive will return the
  32   // timestamp of the most recenly missed tick that did not have OnTimerTick
  33   // called.
  34   virtual base::TimeTicks SetActive(bool active) = 0;
  35
  36   virtual bool Active() const = 0;
  37   virtual void SetTimebaseAndInterval(base::TimeTicks timebase,
  38                                       base::TimeDelta interval) = 0;
  39   virtual base::TimeTicks LastTickTime() = 0;
  40   virtual base::TimeTicks NextTickTime() = 0;
  41
  42  protected:
  43   virtual ~TimeSource() {}
  44
  45  private:
  46   friend class base::RefCounted<TimeSource>;
  47 };
  48
  49 }  // namespace cc
  50
  51 #endif  // CC_SCHEDULER_TIME_SOURCE_H_