1 files changed, 140 insertions, 0 deletions
diff --git a/widget/android/AndroidVsync.cpp b/widget/android/AndroidVsync.cpp
new file mode 100644
index 0000000000..a25644ce80
--- /dev/null
+++ b/widget/android/AndroidVsync.cpp
@@ -0,0 +1,140 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "AndroidVsync.h"
+
+#include "nsTArray.h"
+
+/**
+ * Implementation for the AndroidVsync class.
+ */
+
+namespace mozilla {
+namespace widget {
+
+StaticDataMutex<ThreadSafeWeakPtr<AndroidVsync>> AndroidVsync::sInstance(
+    "AndroidVsync::sInstance");
+
+/* static */ RefPtr<AndroidVsync> AndroidVsync::GetInstance() {
+  auto weakInstance = sInstance.Lock();
+  RefPtr<AndroidVsync> instance(*weakInstance);
+  if (!instance) {
+    instance = new AndroidVsync();
+    *weakInstance = instance;
+  }
+  return instance;
+}
+
+/**
+ * Owned by the Java AndroidVsync instance.
+ */
+class AndroidVsyncSupport final
+    : public java::AndroidVsync::Natives<AndroidVsyncSupport> {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AndroidVsyncSupport)
+
+  using Base = java::AndroidVsync::Natives<AndroidVsyncSupport>;
+  using Base::AttachNative;
+  using Base::DisposeNative;
+
+  explicit AndroidVsyncSupport(AndroidVsync* aAndroidVsync)
+      : mAndroidVsync(std::move(aAndroidVsync),
+                      "AndroidVsyncSupport::mAndroidVsync") {}
+
+  // Called by Java
+  void NotifyVsync(const java::AndroidVsync::LocalRef& aInstance,
+                   int64_t aFrameTimeNanos) {
+    auto androidVsync = mAndroidVsync.Lock();
+    if (*androidVsync) {
+      (*androidVsync)->NotifyVsync(aFrameTimeNanos);
+    }
+  }
+
+  // Called by the AndroidVsync destructor
+  void Unlink() {
+    auto androidVsync = mAndroidVsync.Lock();
+    *androidVsync = nullptr;
+  }
+
+ protected:
+  ~AndroidVsyncSupport() = default;
+
+  DataMutex<AndroidVsync*> mAndroidVsync;
+};
+
+AndroidVsync::AndroidVsync() : mImpl("AndroidVsync.mImpl") {
+  AndroidVsyncSupport::Init();
+
+  auto impl = mImpl.Lock();
+  impl->mSupport = new AndroidVsyncSupport(this);
+  impl->mSupportJava = java::AndroidVsync::New();
+  AndroidVsyncSupport::AttachNative(impl->mSupportJava, impl->mSupport);
+  float fps = impl->mSupportJava->GetRefreshRate();
+  impl->mVsyncDuration = TimeDuration::FromMilliseconds(1000.0 / fps);
+}
+
+AndroidVsync::~AndroidVsync() {
+  auto impl = mImpl.Lock();
+  impl->mInputObservers.Clear();
+  impl->mRenderObservers.Clear();
+  impl->UpdateObservingVsync();
+  impl->mSupport->Unlink();
+}
+
+TimeDuration AndroidVsync::GetVsyncRate() {
+  auto impl = mImpl.Lock();
+  return impl->mVsyncDuration;
+}
+
+void AndroidVsync::RegisterObserver(Observer* aObserver, ObserverType aType) {
+  auto impl = mImpl.Lock();
+  if (aType == AndroidVsync::INPUT) {
+    impl->mInputObservers.AppendElement(aObserver);
+  } else {
+    impl->mRenderObservers.AppendElement(aObserver);
+  }
+  impl->UpdateObservingVsync();
+}
+
+void AndroidVsync::UnregisterObserver(Observer* aObserver, ObserverType aType) {
+  auto impl = mImpl.Lock();
+  if (aType == AndroidVsync::INPUT) {
+    impl->mInputObservers.RemoveElement(aObserver);
+  } else {
+    impl->mRenderObservers.RemoveElement(aObserver);
+  }
+  impl->UpdateObservingVsync();
+}
+
+void AndroidVsync::Impl::UpdateObservingVsync() {
+  bool shouldObserve =
+      !mInputObservers.IsEmpty() || !mRenderObservers.IsEmpty();
+  if (shouldObserve != mObservingVsync) {
+    mObservingVsync = mSupportJava->ObserveVsync(shouldObserve);
+  }
+}
+
+// Always called on the Java UI thread.
+void AndroidVsync::NotifyVsync(int64_t aFrameTimeNanos) {
+  // Convert aFrameTimeNanos to a TimeStamp. The value converts trivially to
+  // the internal ticks representation of TimeStamp_posix; both use the
+  // monotonic clock and are in nanoseconds.
+  TimeStamp timeStamp = TimeStamp::FromSystemTime(aFrameTimeNanos);
+
+  // Do not keep the lock held while calling OnVsync.
+  nsTArray<Observer*> observers;
+  {
+    auto impl = mImpl.Lock();
+    observers.AppendElements(impl->mInputObservers);
+    observers.AppendElements(impl->mRenderObservers);
+  }
+  for (Observer* observer : observers) {
+    observer->OnVsync(timeStamp);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla