gecko-dev/widget/VsyncDispatcher.h

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/* -*- 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 "base/message_loop.h"
#include "mozilla/Mutex.h"
#include "nsISupportsImpl.h"
#include "nsTArray.h"
#include "ThreadSafeRefcountingWithMainThreadDestruction.h"
class MessageLoop;
namespace mozilla {
class TimeStamp;
namespace layers {
class CompositorVsyncObserver;
}
// Controls how and when to enable/disable vsync.
class VsyncSource
{
public:
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncSource)
virtual void EnableVsync() = 0;
virtual void DisableVsync() = 0;
virtual bool IsVsyncEnabled() = 0;
protected:
virtual ~VsyncSource() {}
}; // VsyncSource
class VsyncObserver
{
// Must be destroyed on main thread since the compositor is as well
NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_MAIN_THREAD_DESTRUCTION(VsyncObserver)
public:
// The method called when a vsync occurs. Return true if some work was done.
// Vsync notifications will occur on the hardware vsync thread
virtual bool NotifyVsync(TimeStamp aVsyncTimestamp) = 0;
protected:
VsyncObserver() {}
virtual ~VsyncObserver() {}
}; // VsyncObserver
// VsyncDispatcher is used to dispatch vsync events to the registered observers.
class VsyncDispatcher
{
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncDispatcher)
public:
static VsyncDispatcher* GetInstance();
// Called on the vsync thread when a hardware vsync occurs
// The aVsyncTimestamp can mean different things depending on the platform:
// b2g - The vsync timestamp of the previous frame that was just displayed
// OSX - The vsync timestamp of the upcoming frame
// TODO: Windows / Linux. DOCUMENT THIS WHEN IMPLEMENTING ON THOSE PLATFORMS
// Android: TODO
void NotifyVsync(TimeStamp aVsyncTimestamp);
void SetVsyncSource(VsyncSource* aVsyncSource);
// Compositor vsync observers must be added/removed on the compositor thread
void AddCompositorVsyncObserver(VsyncObserver* aVsyncObserver);
void RemoveCompositorVsyncObserver(VsyncObserver* aVsyncObserver);
private:
VsyncDispatcher();
virtual ~VsyncDispatcher();
void DispatchTouchEvents(bool aNotifiedCompositors, TimeStamp aVsyncTime);
// Called on the vsync thread. Returns true if observers were notified
bool NotifyVsyncObservers(TimeStamp aVsyncTimestamp, nsTArray<nsRefPtr<VsyncObserver>>& aObservers);
// Can have multiple compositors. On desktop, this is 1 compositor per window
Mutex mCompositorObserverLock;
nsTArray<nsRefPtr<VsyncObserver>> mCompositorObservers;
nsRefPtr<VsyncSource> mVsyncSource;
}; // VsyncDispatcher
} // namespace mozilla
#endif // __mozilla_widget_VsyncDispatcher_h