SoftwareVsyncSource.h

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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

*/

#ifndef GFX_SOFTWARE_VSYNC_SOURCE_H

#define GFX_SOFTWARE_VSYNC_SOURCE_H

#include "mozilla/DataMutex.h"

#include "mozilla/Monitor.h"

#include "mozilla/RefPtr.h"

#include "mozilla/TimeStamp.h"

#include "base/thread.h"

#include "nsISupportsImpl.h"

#include "VsyncSource.h"

namespace mozilla::gfx {

// Fallback option to use a software timer to mimic vsync. Useful for gtests

// To mimic a hardware vsync thread, we create a dedicated software timer

// vsync thread.

class SoftwareVsyncSource : public VsyncSource {

 public:

  explicit SoftwareVsyncSource(const TimeDuration& aInitialVsyncRate);

  virtual ~SoftwareVsyncSource();

  void EnableVsync() override;

  void DisableVsync() override;

  bool IsVsyncEnabled() override;

  bool IsInSoftwareVsyncThread();

  void NotifyVsync(const TimeStamp& aVsyncTimestamp,

                   const TimeStamp& aOutputTimestamp) override;

  TimeDuration GetVsyncRate() override;

  void ScheduleNextVsync(TimeStamp aVsyncTimestamp);

  void Shutdown() override;

  // Can be called on any thread

  void SetVsyncRate(const TimeDuration& aNewRate);

 protected:

  // Use a chromium thread because nsITimers* fire on the main thread

  base::Thread* mVsyncThread;

  RefPtr<CancelableRunnable> mCurrentVsyncTask;  // only access on vsync thread

  bool mVsyncEnabled;                            // Only access on main thread

 private:

  DataMutex<TimeDuration> mVsyncRate;  // can be accessed on any thread

};

}  // namespace mozilla::gfx

#endif /* GFX_SOFTWARE_VSYNC_SOURCE_H */