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/*
* Copyright (C) 2011 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef CCDelayBasedTimeSource_h
#define CCDelayBasedTimeSource_h
#include "cc/CCTimeSource.h"
#include "cc/CCTimer.h"
#include <wtf/PassRefPtr.h>
namespace WebCore {
class CCThread;
// This timer implements a time source that achieves the specified interval
// in face of millisecond-precision delayed callbacks and random queueing delays.
class CCDelayBasedTimeSource : public CCTimeSource, CCTimerClient {
public:
static PassRefPtr<CCDelayBasedTimeSource> create(double intervalSeconds, CCThread*);
virtual ~CCDelayBasedTimeSource() { }
virtual void setClient(CCTimeSourceClient* client) OVERRIDE { m_client = client; }
// CCTimeSource implementation
virtual void setTimebaseAndInterval(double timebase, double intervalSeconds) OVERRIDE;
virtual void setActive(bool) OVERRIDE;
virtual bool active() const OVERRIDE { return m_state != STATE_INACTIVE; }
// Get the last and next tick times.
// If not active, nextTickTime will return 0.
virtual double lastTickTime() OVERRIDE;
virtual double nextTickTime() OVERRIDE;
// CCTimerClient implementation.
virtual void onTimerFired() OVERRIDE;
// Virtual for testing.
virtual double monotonicallyIncreasingTime() const;
protected:
CCDelayBasedTimeSource(double interval, CCThread*);
void postNextTickTask(double now);
enum State {
STATE_INACTIVE,
STATE_STARTING,
STATE_ACTIVE,
};
struct Parameters {
Parameters(double interval, double tickTarget)
: interval(interval), tickTarget(tickTarget)
{ }
double interval;
double tickTarget;
};
CCTimeSourceClient* m_client;
bool m_hasTickTarget;
double m_lastTickTime;
// m_currentParameters should only be written by postNextTickTask.
// m_nextParameters will take effect on the next call to postNextTickTask.
// Maintaining a pending set of parameters allows nextTickTime() to always
// reflect the actual time we expect onTimerFired to be called.
Parameters m_currentParameters;
Parameters m_nextParameters;
State m_state;
CCThread* m_thread;
CCTimer m_timer;
};
}
#endif // CCDelayBasedTimeSource_h
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