blob: 009b9a398cdb4258578db19c0cf8b93f3af2e6c5 [file] [log] [blame]
// 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.
#include "base/memory/weak_ptr.h"
#include "cc/base/cc_export.h"
#include "cc/scheduler/time_source.h"
namespace base { class SingleThreadTaskRunner; }
namespace cc {
// This timer implements a time source that achieves the specified interval
// in face of millisecond-precision delayed callbacks and random queueing
// delays.
class CC_EXPORT DelayBasedTimeSource : public TimeSource {
static scoped_refptr<DelayBasedTimeSource> Create(
base::TimeDelta interval, base::SingleThreadTaskRunner* task_runner);
virtual void SetClient(TimeSourceClient* client) OVERRIDE;
// TimeSource implementation
virtual void SetTimebaseAndInterval(base::TimeTicks timebase,
base::TimeDelta interval) OVERRIDE;
virtual void SetActive(bool active) OVERRIDE;
virtual bool Active() const OVERRIDE;
// Get the last and next tick times. nextTimeTime() returns null when
// inactive.
virtual base::TimeTicks LastTickTime() OVERRIDE;
virtual base::TimeTicks NextTickTime() OVERRIDE;
// Virtual for testing.
virtual base::TimeTicks Now() const;
DelayBasedTimeSource(base::TimeDelta interval,
base::SingleThreadTaskRunner* task_runner);
virtual ~DelayBasedTimeSource();
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_;
} // namespace cc