widget/VsyncDispatcher.h
author Botond Ballo <botond@mozilla.com>
Thu, 25 Apr 2019 14:33:17 +0000
changeset 530341 4f70b98aa8705b6906b6bd2a3de66d374addb177
parent 506097 be8b9297085042370ded2cd12b210b7ebeb895a8
permissions -rw-r--r--
Bug 1546139 - Restore the call to AdjustFixedOrStickyLayer() for layers fixed to the RCD-RSF. r=kats This call served two purposes: (1) scroll the fixed layer by the eVisual transform, and (2) adjust it by the fixed margins. The first purpose is now served by applying the eVisual transform to the async zoom container, but we still need the call for the second purpose. Differential Revision: https://phabricator.services.mozilla.com/D28735

/* -*- 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"
#include "VsyncSource.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(const VsyncEvent& aVsync) = 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(const VsyncEvent& aVsync);

  // 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(const VsyncEvent& aVsync);

  // 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