1 files changed, 91 insertions, 0 deletions
diff --git a/gfx/layers/ipc/ThreadSafeRefcountingWithMainThreadDestruction.h b/gfx/layers/ipc/ThreadSafeRefcountingWithMainThreadDestruction.h
new file mode 100644
index 000000000..e64705478
--- /dev/null
+++ b/gfx/layers/ipc/ThreadSafeRefcountingWithMainThreadDestruction.h
@@ -0,0 +1,91 @@
+/* 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 THREADSAFEREFCOUNTINGWITHMAINTHREADDESTRUCTION_H_
+#define THREADSAFEREFCOUNTINGWITHMAINTHREADDESTRUCTION_H_
+
+#include "base/message_loop.h"
+#include "MainThreadUtils.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla {
+namespace layers {
+
+inline MessageLoop* GetMainLoopAssertingMainThread()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  return MessageLoop::current();
+}
+
+inline MessageLoop* GetMainLoop()
+{
+  static MessageLoop* sMainLoop = GetMainLoopAssertingMainThread();
+  return sMainLoop;
+}
+
+struct HelperForMainThreadDestruction
+{
+  HelperForMainThreadDestruction()
+  {
+    MOZ_ASSERT(NS_IsMainThread());
+    GetMainLoop();
+  }
+
+  ~HelperForMainThreadDestruction()
+  {
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+};
+
+template<typename T>
+struct DeleteOnMainThreadTask : public Runnable
+{
+  T* mToDelete;
+  explicit DeleteOnMainThreadTask(T* aToDelete) : mToDelete(aToDelete) {}
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread());
+    mToDelete->DeleteToBeCalledOnMainThread();
+    return NS_OK;
+  }
+};
+
+} // namespace layers
+} // namespace mozilla
+
+#define NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_MAIN_THREAD_DESTRUCTION(_class) \
+public:                                                                       \
+  NS_METHOD_(MozExternalRefCountType) AddRef(void) {                          \
+    MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class)                                \
+    MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt");                      \
+    nsrefcnt count = ++mRefCnt;                                               \
+    NS_LOG_ADDREF(this, count, #_class, sizeof(*this));                       \
+    return (nsrefcnt) count;                                                  \
+  }                                                                           \
+  void DeleteToBeCalledOnMainThread() {                                       \
+    MOZ_ASSERT(NS_IsMainThread());                                            \
+    NS_LOG_RELEASE(this, 0, #_class);                                         \
+    delete this;                                                              \
+  }                                                                           \
+  NS_METHOD_(MozExternalRefCountType) Release(void) {                         \
+    MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release");                          \
+    nsrefcnt count = --mRefCnt;                                               \
+    if (count == 0) {                                                         \
+      if (NS_IsMainThread()) {                                                \
+        DeleteToBeCalledOnMainThread();                                       \
+      } else {                                                                \
+        NS_DispatchToMainThread(                                              \
+          new mozilla::layers::DeleteOnMainThreadTask<_class>(this));         \
+      }                                                                       \
+    } else {                                                                  \
+      NS_LOG_RELEASE(this, count, #_class);                                   \
+    }                                                                         \
+    return count;                                                             \
+  }                                                                           \
+protected:                                                                    \
+  ::mozilla::ThreadSafeAutoRefCnt mRefCnt;                                    \
+private:                                                                      \
+  ::mozilla::layers::HelperForMainThreadDestruction mHelperForMainThreadDestruction; \
+public:
+
+#endif