1 files changed, 431 insertions, 0 deletions
diff --git a/widget/gtk/WaylandVsyncSource.cpp b/widget/gtk/WaylandVsyncSource.cpp
new file mode 100644
index 0000000000..e5bca04837
--- /dev/null
+++ b/widget/gtk/WaylandVsyncSource.cpp
@@ -0,0 +1,431 @@
+/* -*- 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/. */
+
+#ifdef MOZ_WAYLAND
+
+#  include "WaylandVsyncSource.h"
+#  include "mozilla/UniquePtr.h"
+#  include "nsThreadUtils.h"
+#  include "nsISupportsImpl.h"
+#  include "MainThreadUtils.h"
+#  include "mozilla/ScopeExit.h"
+#  include "nsGtkUtils.h"
+#  include "mozilla/StaticPrefs_layout.h"
+#  include "mozilla/StaticPrefs_widget.h"
+#  include "nsWindow.h"
+
+#  include <gdk/gdkwayland.h>
+
+#  ifdef MOZ_LOGGING
+#    include "mozilla/Logging.h"
+#    include "nsTArray.h"
+#    include "Units.h"
+extern mozilla::LazyLogModule gWidgetVsync;
+#    undef LOG
+#    define LOG(str, ...)                             \
+      MOZ_LOG(gWidgetVsync, mozilla::LogLevel::Debug, \
+              ("[nsWindow %p]: " str, GetWindowForLogging(), ##__VA_ARGS__))
+#  else
+#    define LOG(...)
+#  endif /* MOZ_LOGGING */
+
+using namespace mozilla::widget;
+
+namespace mozilla {
+
+static void WaylandVsyncSourceCallbackHandler(void* aData,
+                                              struct wl_callback* aCallback,
+                                              uint32_t aTime) {
+  RefPtr context = static_cast<WaylandVsyncSource*>(aData);
+  context->FrameCallback(aCallback, aTime);
+}
+
+static const struct wl_callback_listener WaylandVsyncSourceCallbackListener = {
+    WaylandVsyncSourceCallbackHandler};
+
+static void NativeLayerRootWaylandVsyncCallback(void* aData, uint32_t aTime) {
+  RefPtr context = static_cast<WaylandVsyncSource*>(aData);
+  context->FrameCallback(nullptr, aTime);
+}
+
+static float GetFPS(TimeDuration aVsyncRate) {
+  return 1000.0f / float(aVsyncRate.ToMilliseconds());
+}
+
+static nsTArray<WaylandVsyncSource*> gWaylandVsyncSources;
+
+Maybe<TimeDuration> WaylandVsyncSource::GetFastestVsyncRate() {
+  Maybe<TimeDuration> retVal;
+  for (auto* source : gWaylandVsyncSources) {
+    auto rate = source->GetVsyncRateIfEnabled();
+    if (!rate) {
+      continue;
+    }
+    if (!retVal.isSome()) {
+      retVal.emplace(*rate);
+    } else if (*rate < *retVal) {
+      retVal.ref() = *rate;
+    }
+  }
+
+  return retVal;
+}
+
+WaylandVsyncSource::WaylandVsyncSource(nsWindow* aWindow)
+    : mMutex("WaylandVsyncSource"),
+      mVsyncRate(TimeDuration::FromMilliseconds(1000.0 / 60.0)),
+      mLastVsyncTimeStamp(TimeStamp::Now()),
+      mWindow(aWindow),
+      mIdleTimeout(1000 / StaticPrefs::layout_throttled_frame_rate()) {
+  MOZ_ASSERT(NS_IsMainThread());
+  gWaylandVsyncSources.AppendElement(this);
+}
+
+WaylandVsyncSource::~WaylandVsyncSource() {
+  gWaylandVsyncSources.RemoveElement(this);
+}
+
+void WaylandVsyncSource::MaybeUpdateSource(MozContainer* aContainer) {
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::MaybeUpdateSource fps %f", GetFPS(mVsyncRate));
+
+  if (aContainer == mContainer) {
+    LOG("  mContainer is the same, quit.");
+    return;
+  }
+
+  mNativeLayerRoot = nullptr;
+  mContainer = aContainer;
+
+  if (mMonitorEnabled) {
+    LOG("  monitor enabled, ask for Refresh()");
+    mCallbackRequested = false;
+    Refresh(lock);
+  }
+}
+
+void WaylandVsyncSource::MaybeUpdateSource(
+    const RefPtr<NativeLayerRootWayland>& aNativeLayerRoot) {
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::MaybeUpdateSource aNativeLayerRoot fps %f",
+      GetFPS(mVsyncRate));
+
+  if (aNativeLayerRoot == mNativeLayerRoot) {
+    LOG("  mNativeLayerRoot is the same, quit.");
+    return;
+  }
+
+  mNativeLayerRoot = aNativeLayerRoot;
+  mContainer = nullptr;
+
+  if (mMonitorEnabled) {
+    LOG("  monitor enabled, ask for Refresh()");
+    mCallbackRequested = false;
+    Refresh(lock);
+  }
+}
+
+void WaylandVsyncSource::Refresh(const MutexAutoLock& aProofOfLock) {
+  mMutex.AssertCurrentThreadOwns();
+
+  LOG("WaylandVsyncSource::Refresh fps %f\n", GetFPS(mVsyncRate));
+
+  if (!(mContainer || mNativeLayerRoot) || !mMonitorEnabled || !mVsyncEnabled ||
+      mCallbackRequested) {
+    // We don't need to do anything because:
+    // * We are unwanted by our widget or monitor, or
+    // * The last frame callback hasn't yet run to see that it had been shut
+    //   down, so we can reuse it after having set mVsyncEnabled to true.
+    LOG("  quit mContainer %d mNativeLayerRoot %d mMonitorEnabled %d "
+        "mVsyncEnabled %d mCallbackRequested %d",
+        !!mContainer, !!mNativeLayerRoot, mMonitorEnabled, mVsyncEnabled,
+        !!mCallbackRequested);
+    return;
+  }
+
+  if (mContainer) {
+    MozContainerSurfaceLock lock(mContainer);
+    struct wl_surface* surface = lock.GetSurface();
+    LOG("  refresh from mContainer, wl_surface %p", surface);
+    if (!surface) {
+      LOG("  we're missing wl_surface, register Refresh() callback");
+      // The surface hasn't been created yet. Try again when the surface is
+      // ready.
+      RefPtr<WaylandVsyncSource> self(this);
+      moz_container_wayland_add_initial_draw_callback_locked(
+          mContainer, [self]() -> void {
+            MutexAutoLock lock(self->mMutex);
+            self->Refresh(lock);
+          });
+      return;
+    }
+  }
+
+  // Vsync is enabled, but we don't have a callback configured. Set one up so
+  // we can get to work.
+  SetupFrameCallback(aProofOfLock);
+  const TimeStamp lastVSync = TimeStamp::Now();
+  mLastVsyncTimeStamp = lastVSync;
+  TimeStamp outputTimestamp = mLastVsyncTimeStamp + mVsyncRate;
+
+  {
+    MutexAutoUnlock unlock(mMutex);
+    NotifyVsync(lastVSync, outputTimestamp);
+  }
+}
+
+void WaylandVsyncSource::EnableMonitor() {
+  LOG("WaylandVsyncSource::EnableMonitor");
+  MutexAutoLock lock(mMutex);
+  if (mMonitorEnabled) {
+    return;
+  }
+  mMonitorEnabled = true;
+  Refresh(lock);
+}
+
+void WaylandVsyncSource::DisableMonitor() {
+  LOG("WaylandVsyncSource::DisableMonitor");
+  MutexAutoLock lock(mMutex);
+  if (!mMonitorEnabled) {
+    return;
+  }
+  mMonitorEnabled = false;
+  mCallbackRequested = false;
+}
+
+void WaylandVsyncSource::SetupFrameCallback(const MutexAutoLock& aProofOfLock) {
+  mMutex.AssertCurrentThreadOwns();
+  MOZ_ASSERT(!mCallbackRequested);
+
+  LOG("WaylandVsyncSource::SetupFrameCallback");
+
+  if (mNativeLayerRoot) {
+    LOG("  use mNativeLayerRoot");
+    mNativeLayerRoot->RequestFrameCallback(&NativeLayerRootWaylandVsyncCallback,
+                                           this);
+  } else {
+    MozContainerSurfaceLock lock(mContainer);
+    struct wl_surface* surface = lock.GetSurface();
+    LOG("  use mContainer, wl_surface %p", surface);
+    if (!surface) {
+      // We don't have a surface, either due to being called before it was made
+      // available in the mozcontainer, or after it was destroyed. We're all
+      // done regardless.
+      LOG("  missing wl_surface, quit.");
+      return;
+    }
+
+    LOG("  register frame callback");
+    MozClearPointer(mCallback, wl_callback_destroy);
+    mCallback = wl_surface_frame(surface);
+    wl_callback_add_listener(mCallback, &WaylandVsyncSourceCallbackListener,
+                             this);
+    wl_surface_commit(surface);
+    wl_display_flush(WaylandDisplayGet()->GetDisplay());
+
+    if (!mIdleTimerID) {
+      mIdleTimerID = g_timeout_add(
+          mIdleTimeout,
+          [](void* data) -> gint {
+            RefPtr vsync = static_cast<WaylandVsyncSource*>(data);
+            if (vsync->IdleCallback()) {
+              // We want to fire again, so don't clear mIdleTimerID
+              return G_SOURCE_CONTINUE;
+            }
+            // No need for g_source_remove, caller does it for us.
+            vsync->mIdleTimerID = 0;
+            return G_SOURCE_REMOVE;
+          },
+          this);
+    }
+  }
+
+  mCallbackRequested = true;
+}
+
+bool WaylandVsyncSource::IdleCallback() {
+  LOG("WaylandVsyncSource::IdleCallback");
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+  RefPtr<nsWindow> window;
+  TimeStamp lastVSync;
+  TimeStamp outputTimestamp;
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (!mVsyncEnabled || !mMonitorEnabled) {
+      // We are unwanted by either our creator or our consumer, so we just stop
+      // here without setting up a new frame callback.
+      LOG("  quit, mVsyncEnabled %d mMonitorEnabled %d", mVsyncEnabled,
+          mMonitorEnabled);
+      return false;
+    }
+
+    const auto now = TimeStamp::Now();
+    const auto timeSinceLastVSync = now - mLastVsyncTimeStamp;
+    if (timeSinceLastVSync.ToMilliseconds() < mIdleTimeout) {
+      // We're not idle, we want to fire the timer again.
+      return true;
+    }
+
+    LOG("  fire idle vsync");
+    CalculateVsyncRate(lock, now);
+    mLastVsyncTimeStamp = lastVSync = now;
+
+    outputTimestamp = mLastVsyncTimeStamp + mVsyncRate;
+    window = mWindow;
+  }
+
+  // This could disable vsync.
+  window->NotifyOcclusionState(OcclusionState::OCCLUDED);
+
+  if (window->IsDestroyed()) {
+    return false;
+  }
+  // Make sure to fire vsync now even if we get disabled afterwards.
+  // This gives an opportunity to clean up after the visibility state change.
+  // FIXME: Do we really need to do this?
+  NotifyVsync(lastVSync, outputTimestamp);
+  return StaticPrefs::widget_wayland_vsync_keep_firing_at_idle();
+}
+
+void WaylandVsyncSource::FrameCallback(wl_callback* aCallback, uint32_t aTime) {
+  LOG("WaylandVsyncSource::FrameCallback");
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+  {
+    // This might enable vsync.
+    RefPtr window = mWindow;
+    window->NotifyOcclusionState(OcclusionState::VISIBLE);
+    // NotifyOcclusionState can destroy us.
+    if (window->IsDestroyed()) {
+      return;
+    }
+  }
+
+  MutexAutoLock lock(mMutex);
+  mCallbackRequested = false;
+
+  // NotifyOcclusionState() can clear and create new mCallback by
+  // EnableVsync()/Refresh(). So don't delete newly created frame callback.
+  if (aCallback && aCallback == mCallback) {
+    MozClearPointer(mCallback, wl_callback_destroy);
+  }
+
+  if (!mVsyncEnabled || !mMonitorEnabled) {
+    // We are unwanted by either our creator or our consumer, so we just stop
+    // here without setting up a new frame callback.
+    LOG("  quit, mVsyncEnabled %d mMonitorEnabled %d", mVsyncEnabled,
+        mMonitorEnabled);
+    return;
+  }
+
+  // Configure our next frame callback.
+  SetupFrameCallback(lock);
+
+  int64_t tick = BaseTimeDurationPlatformUtils::TicksFromMilliseconds(aTime);
+  const auto callbackTimeStamp = TimeStamp::FromSystemTime(tick);
+  const auto now = TimeStamp::Now();
+
+  // If the callback timestamp is close enough to our timestamp, use it,
+  // otherwise use the current time.
+  const TimeStamp& vsyncTimestamp =
+      std::abs((now - callbackTimeStamp).ToMilliseconds()) < 50.0
+          ? callbackTimeStamp
+          : now;
+
+  CalculateVsyncRate(lock, vsyncTimestamp);
+  mLastVsyncTimeStamp = vsyncTimestamp;
+  const TimeStamp outputTimestamp = vsyncTimestamp + mVsyncRate;
+
+  {
+    MutexAutoUnlock unlock(mMutex);
+    NotifyVsync(vsyncTimestamp, outputTimestamp);
+  }
+}
+
+TimeDuration WaylandVsyncSource::GetVsyncRate() {
+  MutexAutoLock lock(mMutex);
+  return mVsyncRate;
+}
+
+Maybe<TimeDuration> WaylandVsyncSource::GetVsyncRateIfEnabled() {
+  MutexAutoLock lock(mMutex);
+  if (!mVsyncEnabled) {
+    return Nothing();
+  }
+  return Some(mVsyncRate);
+}
+
+void WaylandVsyncSource::CalculateVsyncRate(const MutexAutoLock& aProofOfLock,
+                                            TimeStamp aVsyncTimestamp) {
+  mMutex.AssertCurrentThreadOwns();
+
+  double duration = (aVsyncTimestamp - mLastVsyncTimeStamp).ToMilliseconds();
+  double curVsyncRate = mVsyncRate.ToMilliseconds();
+
+  LOG("WaylandVsyncSource::CalculateVsyncRate start fps %f\n",
+      GetFPS(mVsyncRate));
+
+  double correction;
+  if (duration > curVsyncRate) {
+    correction = fmin(curVsyncRate, (duration - curVsyncRate) / 10);
+    mVsyncRate += TimeDuration::FromMilliseconds(correction);
+  } else {
+    correction = fmin(curVsyncRate / 2, (curVsyncRate - duration) / 10);
+    mVsyncRate -= TimeDuration::FromMilliseconds(correction);
+  }
+
+  LOG("  new fps %f correction %f\n", GetFPS(mVsyncRate), correction);
+}
+
+void WaylandVsyncSource::EnableVsync() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::EnableVsync fps %f\n", GetFPS(mVsyncRate));
+  if (mVsyncEnabled || mIsShutdown) {
+    LOG("  early quit");
+    return;
+  }
+  mVsyncEnabled = true;
+  Refresh(lock);
+}
+
+void WaylandVsyncSource::DisableVsync() {
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::DisableVsync fps %f\n", GetFPS(mVsyncRate));
+  mVsyncEnabled = false;
+  mCallbackRequested = false;
+}
+
+bool WaylandVsyncSource::IsVsyncEnabled() {
+  MutexAutoLock lock(mMutex);
+  return mVsyncEnabled;
+}
+
+void WaylandVsyncSource::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::Shutdown fps %f\n", GetFPS(mVsyncRate));
+  mContainer = nullptr;
+  mNativeLayerRoot = nullptr;
+  mIsShutdown = true;
+  mVsyncEnabled = false;
+  mCallbackRequested = false;
+  MozClearHandleID(mIdleTimerID, g_source_remove);
+  MozClearPointer(mCallback, wl_callback_destroy);
+}
+
+}  // namespace mozilla
+
+#endif  // MOZ_WAYLAND