Source code

Revision control

Other Tools

/* -*- 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 */
#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"
#include "VsyncSource.h"
namespace mozilla {
class VsyncObserver {
// 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(const VsyncEvent& aVsync) = 0;
VsyncObserver() = default;
virtual ~VsyncObserver() = default;
}; // 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 {
explicit CompositorVsyncDispatcher(RefPtr<gfx::VsyncSource> aVsyncSource);
// Called on the vsync thread when a hardware vsync occurs
void NotifyVsync(const VsyncEvent& aVsync);
void MoveToSource(const RefPtr<gfx::VsyncSource>& aVsyncSource);
// Compositor vsync observers must be added/removed on the compositor thread
void SetCompositorVsyncObserver(VsyncObserver* aVsyncObserver);
void Shutdown();
virtual ~CompositorVsyncDispatcher();
void ObserveVsync(bool aEnable);
RefPtr<gfx::VsyncSource> mVsyncSource;
Mutex mCompositorObserverLock;
RefPtr<VsyncObserver> mCompositorVsyncObserver;
bool mDidShutdown;
// Dispatch vsync event to ipc actor parent and chrome RefreshTimer.
class RefreshTimerVsyncDispatcher final {
explicit RefreshTimerVsyncDispatcher(gfx::VsyncSource::Display* aDisplay);
// Please check CompositorVsyncDispatcher::NotifyVsync().
void NotifyVsync(const VsyncEvent& aVsync);
void MoveToDisplay(gfx::VsyncSource::Display* aDisplay);
// 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);
virtual ~RefreshTimerVsyncDispatcher();
void UpdateVsyncStatus();
bool NeedsVsync();
// We need to hold a weak ref to the display we belong to in order to notify
// it of our vsync requirement. The display holds a RefPtr to us, so we can't
// hold a RefPtr back without causing a cyclic dependency.
gfx::VsyncSource::Display* mDisplay;
Mutex mRefreshTimersLock;
RefPtr<VsyncObserver> mParentRefreshTimer;
nsTArray<RefPtr<VsyncObserver>> mChildRefreshTimers;
} // namespace mozilla
#endif // mozilla_widget_VsyncDispatcher_h