1 files changed, 111 insertions, 0 deletions
diff --git a/widget/VsyncDispatcher.h b/widget/VsyncDispatcher.h
new file mode 100644
index 0000000000..bdaf11e699
--- /dev/null
+++ b/widget/VsyncDispatcher.h
@@ -0,0 +1,111 @@
+/* -*- 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() = 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 {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorVsyncDispatcher)
+
+ public:
+  CompositorVsyncDispatcher();
+  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();
+
+ private:
+  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 {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RefreshTimerVsyncDispatcher)
+
+ public:
+  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);
+
+ private:
+  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