1 files changed, 134 insertions, 0 deletions
diff --git a/gfx/thebes/SoftwareVsyncSource.cpp b/gfx/thebes/SoftwareVsyncSource.cpp
new file mode 100644
index 0000000000..e3fc64f8f7
--- /dev/null
+++ b/gfx/thebes/SoftwareVsyncSource.cpp
@@ -0,0 +1,134 @@
+/* -*- Mode: C++; tab-width: 20; 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/.
+ */
+
+#include "SoftwareVsyncSource.h"
+#include "base/task.h"
+#include "gfxPlatform.h"
+#include "nsThreadUtils.h"
+
+using namespace mozilla;
+
+SoftwareVsyncSource::SoftwareVsyncSource() {
+  MOZ_ASSERT(NS_IsMainThread());
+  mGlobalDisplay = new SoftwareDisplay();
+}
+
+SoftwareVsyncSource::~SoftwareVsyncSource() {
+  MOZ_ASSERT(NS_IsMainThread());
+  mGlobalDisplay = nullptr;
+}
+
+SoftwareDisplay::SoftwareDisplay() : mVsyncEnabled(false) {
+  // Mimic 60 fps
+  MOZ_ASSERT(NS_IsMainThread());
+  const double rate = 1000.0 / (double)gfxPlatform::GetSoftwareVsyncRate();
+  mVsyncRate = mozilla::TimeDuration::FromMilliseconds(rate);
+  mVsyncThread = new base::Thread("SoftwareVsyncThread");
+  MOZ_RELEASE_ASSERT(mVsyncThread->Start(),
+                     "GFX: Could not start software vsync thread");
+}
+
+SoftwareDisplay::~SoftwareDisplay() = default;
+
+void SoftwareDisplay::EnableVsync() {
+  MOZ_ASSERT(mVsyncThread->IsRunning());
+  if (NS_IsMainThread()) {
+    if (mVsyncEnabled) {
+      return;
+    }
+    mVsyncEnabled = true;
+
+    mVsyncThread->message_loop()->PostTask(NewRunnableMethod(
+        "SoftwareDisplay::EnableVsync", this, &SoftwareDisplay::EnableVsync));
+    return;
+  }
+
+  MOZ_ASSERT(IsInSoftwareVsyncThread());
+  TimeStamp vsyncTime = TimeStamp::Now();
+  TimeStamp outputTime = vsyncTime + mVsyncRate;
+  NotifyVsync(vsyncTime, outputTime);
+}
+
+void SoftwareDisplay::DisableVsync() {
+  MOZ_ASSERT(mVsyncThread->IsRunning());
+  if (NS_IsMainThread()) {
+    if (!mVsyncEnabled) {
+      return;
+    }
+    mVsyncEnabled = false;
+
+    mVsyncThread->message_loop()->PostTask(NewRunnableMethod(
+        "SoftwareDisplay::DisableVsync", this, &SoftwareDisplay::DisableVsync));
+    return;
+  }
+
+  MOZ_ASSERT(IsInSoftwareVsyncThread());
+  if (mCurrentVsyncTask) {
+    mCurrentVsyncTask->Cancel();
+    mCurrentVsyncTask = nullptr;
+  }
+}
+
+bool SoftwareDisplay::IsVsyncEnabled() {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mVsyncEnabled;
+}
+
+bool SoftwareDisplay::IsInSoftwareVsyncThread() {
+  return mVsyncThread->thread_id() == PlatformThread::CurrentId();
+}
+
+void SoftwareDisplay::NotifyVsync(const mozilla::TimeStamp& aVsyncTimestamp,
+                                  const mozilla::TimeStamp& aOutputTimestamp) {
+  MOZ_ASSERT(IsInSoftwareVsyncThread());
+
+  mozilla::TimeStamp displayVsyncTime = aVsyncTimestamp;
+  mozilla::TimeStamp now = mozilla::TimeStamp::Now();
+  // Posted tasks can only have integer millisecond delays
+  // whereas TimeDurations can have floating point delays.
+  // Thus the vsync timestamp can be in the future, which large parts
+  // of the system can't handle, including animations. Force the timestamp to be
+  // now.
+  if (aVsyncTimestamp > now) {
+    displayVsyncTime = now;
+  }
+
+  Display::NotifyVsync(displayVsyncTime, aOutputTimestamp);
+
+  // Prevent skew by still scheduling based on the original
+  // vsync timestamp
+  ScheduleNextVsync(aVsyncTimestamp);
+}
+
+mozilla::TimeDuration SoftwareDisplay::GetVsyncRate() { return mVsyncRate; }
+
+void SoftwareDisplay::ScheduleNextVsync(mozilla::TimeStamp aVsyncTimestamp) {
+  MOZ_ASSERT(IsInSoftwareVsyncThread());
+  mozilla::TimeStamp nextVsync = aVsyncTimestamp + mVsyncRate;
+  mozilla::TimeDuration delay = nextVsync - mozilla::TimeStamp::Now();
+  if (delay.ToMilliseconds() < 0) {
+    delay = mozilla::TimeDuration::FromMilliseconds(0);
+    nextVsync = mozilla::TimeStamp::Now();
+  }
+
+  TimeStamp outputTime = nextVsync + mVsyncRate;
+
+  mCurrentVsyncTask =
+      NewCancelableRunnableMethod<mozilla::TimeStamp, mozilla::TimeStamp>(
+          "SoftwareDisplay::NotifyVsync", this, &SoftwareDisplay::NotifyVsync,
+          nextVsync, outputTime);
+
+  RefPtr<Runnable> addrefedTask = mCurrentVsyncTask;
+  mVsyncThread->message_loop()->PostDelayedTask(addrefedTask.forget(),
+                                                delay.ToMilliseconds());
+}
+
+void SoftwareDisplay::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  DisableVsync();
+  mVsyncThread->Stop();
+  delete mVsyncThread;
+}