1 files changed, 119 insertions, 0 deletions
diff --git a/gfx/layers/apz/util/APZThreadUtils.cpp b/gfx/layers/apz/util/APZThreadUtils.cpp
new file mode 100644
index 0000000000..d3bf43e61d
--- /dev/null
+++ b/gfx/layers/apz/util/APZThreadUtils.cpp
@@ -0,0 +1,119 @@
+/* -*- 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 "APZThreadUtils.h"
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/ProfilerRunnable.h"
+#include "mozilla/StaticMutex.h"
+
+#include "nsISerialEventTarget.h"
+#include "nsThreadUtils.h"
+#include "nsXULAppAPI.h"
+
+namespace mozilla {
+namespace layers {
+
+static bool sThreadAssertionsEnabled = true;
+static StaticRefPtr<nsISerialEventTarget> sControllerThread;
+static StaticMutex sControllerThreadMutex MOZ_UNANNOTATED;
+
+/*static*/
+void APZThreadUtils::SetThreadAssertionsEnabled(bool aEnabled) {
+  StaticMutexAutoLock lock(sControllerThreadMutex);
+  sThreadAssertionsEnabled = aEnabled;
+}
+
+/*static*/
+bool APZThreadUtils::GetThreadAssertionsEnabled() {
+  StaticMutexAutoLock lock(sControllerThreadMutex);
+  return sThreadAssertionsEnabled;
+}
+
+/*static*/
+void APZThreadUtils::SetControllerThread(nsISerialEventTarget* aThread) {
+  // We must either be setting the initial controller thread, or removing it,
+  // or re-using an existing controller thread.
+  StaticMutexAutoLock lock(sControllerThreadMutex);
+  MOZ_ASSERT(!sControllerThread || !aThread || sControllerThread == aThread);
+  if (aThread != sControllerThread) {
+    // This can only happen once, on startup.
+    sControllerThread = aThread;
+    ClearOnShutdown(&sControllerThread);
+  }
+}
+
+/*static*/
+void APZThreadUtils::AssertOnControllerThread() {
+#if DEBUG
+  if (!GetThreadAssertionsEnabled()) {
+    return;
+  }
+  StaticMutexAutoLock lock(sControllerThreadMutex);
+  MOZ_ASSERT(sControllerThread && sControllerThread->IsOnCurrentThread());
+#endif
+}
+
+/*static*/
+void APZThreadUtils::RunOnControllerThread(RefPtr<Runnable>&& aTask,
+                                           uint32_t flags) {
+  RefPtr<nsISerialEventTarget> thread;
+  {
+    StaticMutexAutoLock lock(sControllerThreadMutex);
+    thread = sControllerThread;
+  }
+  RefPtr<Runnable> task = std::move(aTask);
+
+  if (!thread) {
+    // Could happen on startup or if Shutdown() got called.
+    NS_WARNING("Dropping task posted to controller thread");
+    return;
+  }
+
+  if (thread->IsOnCurrentThread()) {
+    AUTO_PROFILE_FOLLOWING_RUNNABLE(task);
+    task->Run();
+  } else {
+    thread->Dispatch(task.forget(), flags);
+  }
+}
+
+/*static*/
+bool APZThreadUtils::IsControllerThread() {
+  StaticMutexAutoLock lock(sControllerThreadMutex);
+  return sControllerThread && sControllerThread->IsOnCurrentThread();
+}
+
+/*static*/
+bool APZThreadUtils::IsControllerThreadAlive() {
+  StaticMutexAutoLock lock(sControllerThreadMutex);
+  return !!sControllerThread;
+}
+
+/*static*/
+void APZThreadUtils::DelayedDispatch(already_AddRefed<Runnable> aRunnable,
+                                     int aDelayMs) {
+  MOZ_ASSERT(!XRE_IsContentProcess(),
+             "ContentProcessController should only be used remotely.");
+  RefPtr<nsISerialEventTarget> thread;
+  {
+    StaticMutexAutoLock lock(sControllerThreadMutex);
+    thread = sControllerThread;
+  }
+  if (!thread) {
+    // Could happen on startup
+    NS_WARNING("Dropping task posted to controller thread");
+    return;
+  }
+  if (aDelayMs) {
+    thread->DelayedDispatch(std::move(aRunnable), aDelayMs);
+  } else {
+    thread->Dispatch(std::move(aRunnable));
+  }
+}
+
+}  // namespace layers
+}  // namespace mozilla