/* -*- Mode: C++; tab-width: 2; 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 mozilla_widget_VsyncDispatcher_h

#define mozilla_widget_VsyncDispatcher_h

#include "mozilla/Mutex.h"

#include "mozilla/TimeStamp.h"

#include "nsISupportsImpl.h"

#include "nsTArray.h"

#include "mozilla/RefPtr.h"

namespace mozilla {

class VsyncObserver

{

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncObserver)

public:

  // The method called when a vsync occurs. Return true if some work was done.

  // In general, this vsync notification will occur on the hardware vsync

  // thread from VsyncSource. But it might also be called on PVsync ipc thread

  // if this notification is cross process. Thus all observer should check the

  // thread model before handling the real task.

  virtual bool NotifyVsync(TimeStamp aVsyncTimestamp) = 0;

protected:

  VsyncObserver() {}

  virtual ~VsyncObserver() {}

}; // VsyncObserver

// Used to dispatch vsync events in the parent process to compositors.

//

// When the compositor is in-process, CompositorWidgets own a

// CompositorVsyncDispatcher, and directly attach the compositor's observer

// to it.

//

// When the compositor is out-of-process, the CompositorWidgetDelegate owns

// the vsync dispatcher instead. The widget receives vsync observer/unobserve

// commands via IPDL, and uses this to attach a CompositorWidgetVsyncObserver.

// This observer forwards vsync notifications (on the vsync thread) to a

// dedicated vsync I/O thread, which then forwards the notification to the

// compositor thread in the compositor process.

class CompositorVsyncDispatcher final

{

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorVsyncDispatcher)

public:

  CompositorVsyncDispatcher();

  // Called on the vsync thread when a hardware vsync occurs

  void NotifyVsync(TimeStamp aVsyncTimestamp);

  // Compositor vsync observers must be added/removed on the compositor thread

  void SetCompositorVsyncObserver(VsyncObserver* aVsyncObserver);

  void Shutdown();

private:

  virtual ~CompositorVsyncDispatcher();

  void ObserveVsync(bool aEnable);

  Mutex mCompositorObserverLock;

  RefPtr<VsyncObserver> mCompositorVsyncObserver;

  bool mDidShutdown;

};

// Dispatch vsync event to ipc actor parent and chrome RefreshTimer.

class RefreshTimerVsyncDispatcher final

{

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RefreshTimerVsyncDispatcher)

public:

  RefreshTimerVsyncDispatcher();

  // Please check CompositorVsyncDispatcher::NotifyVsync().

  void NotifyVsync(TimeStamp aVsyncTimestamp);

  // Set chrome process's RefreshTimer to this dispatcher.

  // This function can be called from any thread.

  void SetParentRefreshTimer(VsyncObserver* aVsyncObserver);

  // Add or remove the content process' RefreshTimer to this dispatcher. This

  // will be a no-op for AddChildRefreshTimer() if the observer is already

  // registered.

  // These functions can be called from any thread.

  void AddChildRefreshTimer(VsyncObserver* aVsyncObserver);

  void RemoveChildRefreshTimer(VsyncObserver* aVsyncObserver);

private:

  virtual ~RefreshTimerVsyncDispatcher();

  void UpdateVsyncStatus();

  bool NeedsVsync();

  Mutex mRefreshTimersLock;

  RefPtr<VsyncObserver> mParentRefreshTimer;

  nsTArray<RefPtr<VsyncObserver>> mChildRefreshTimers;

};

} // namespace mozilla

#endif // mozilla_widget_VsyncDispatcher_h