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// Copyright 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_SCHEDULER_DELAY_BASED_TIME_SOURCE_H_
#define CC_SCHEDULER_DELAY_BASED_TIME_SOURCE_H_
#include <string>
#include "base/memory/weak_ptr.h"
#include "base/values.h"
#include "cc/base/cc_export.h"
namespace base {
namespace debug {
class TracedValue;
}
class SingleThreadTaskRunner;
}
namespace cc {
class CC_EXPORT TimeSourceClient {
public:
virtual void OnTimerTick() = 0;
protected:
virtual ~TimeSourceClient() {}
};
// This timer implements a time source that achieves the specified interval
// in face of millisecond-precision delayed callbacks and random queueing
// delays. DelayBasedTimeSource uses base::TimeTicks::Now as its timebase.
class CC_EXPORT DelayBasedTimeSource
: public base::RefCounted<DelayBasedTimeSource> {
public:
static scoped_refptr<DelayBasedTimeSource> Create(
base::TimeDelta interval, base::SingleThreadTaskRunner* task_runner);
virtual void SetClient(TimeSourceClient* client);
// TimeSource implementation
virtual void SetTimebaseAndInterval(base::TimeTicks timebase,
base::TimeDelta interval);
base::TimeDelta Interval() const { return next_parameters_.interval; }
virtual base::TimeTicks SetActive(bool active);
virtual bool Active() const;
// Get the last and next tick times. NextTickTime() returns null when
// inactive.
virtual base::TimeTicks LastTickTime() const;
virtual base::TimeTicks NextTickTime() const;
// Virtual for testing.
virtual base::TimeTicks Now() const;
virtual void AsValueInto(base::debug::TracedValue* dict) const;
protected:
DelayBasedTimeSource(base::TimeDelta interval,
base::SingleThreadTaskRunner* task_runner);
virtual ~DelayBasedTimeSource();
virtual std::string TypeString() const;
base::TimeTicks NextTickTarget(base::TimeTicks now);
void PostNextTickTask(base::TimeTicks now);
void OnTimerFired();
struct Parameters {
Parameters(base::TimeDelta interval, base::TimeTicks tick_target)
: interval(interval), tick_target(tick_target) {}
base::TimeDelta interval;
base::TimeTicks tick_target;
};
TimeSourceClient* client_;
base::TimeTicks last_tick_time_;
// current_parameters_ should only be written by PostNextTickTask.
// next_parameters_ 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 current_parameters_;
Parameters next_parameters_;
bool active_;
base::SingleThreadTaskRunner* task_runner_;
base::WeakPtrFactory<DelayBasedTimeSource> weak_factory_;
private:
friend class base::RefCounted<DelayBasedTimeSource>;
DISALLOW_COPY_AND_ASSIGN(DelayBasedTimeSource);
};
// DelayBasedTimeSource uses base::TimeTicks::HighResNow as its timebase.
class DelayBasedTimeSourceHighRes : public DelayBasedTimeSource {
public:
static scoped_refptr<DelayBasedTimeSourceHighRes> Create(
base::TimeDelta interval, base::SingleThreadTaskRunner* task_runner);
base::TimeTicks Now() const override;
protected:
DelayBasedTimeSourceHighRes(base::TimeDelta interval,
base::SingleThreadTaskRunner* task_runner);
~DelayBasedTimeSourceHighRes() override;
std::string TypeString() const override;
private:
DISALLOW_COPY_AND_ASSIGN(DelayBasedTimeSourceHighRes);
};
} // namespace cc
#endif // CC_SCHEDULER_DELAY_BASED_TIME_SOURCE_H_
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