1 files changed, 59 insertions, 0 deletions
diff --git a/gfx/layers/IPDLActor.h b/gfx/layers/IPDLActor.h
new file mode 100644
index 0000000000..b5eb04d0dc
--- /dev/null
+++ b/gfx/layers/IPDLActor.h
@@ -0,0 +1,59 @@
+/* -*- 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/. */
+
+#ifndef MOZILLA_LAYERS_IPDLACTOR_H
+#define MOZILLA_LAYERS_IPDLACTOR_H
+
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/layers/CompositableForwarder.h"
+#include "mozilla/Unused.h"
+#include "gfxPlatform.h"
+
+namespace mozilla {
+namespace layers {
+
+/// A base class to facilitate the deallocation of IPDL actors.
+///
+/// Implements the parent side of the simple deallocation handshake.
+/// Override the Destroy method rather than the ActorDestroy method.
+template <typename Protocol>
+class ParentActor : public Protocol {
+ public:
+  ParentActor() : mDestroyed(false) {}
+
+  ~ParentActor() { MOZ_ASSERT(mDestroyed); }
+
+  bool CanSend() const { return !mDestroyed; }
+
+  // Override this rather than ActorDestroy
+  virtual void Destroy() {}
+
+  mozilla::ipc::IPCResult RecvDestroy() final {
+    DestroyIfNeeded();
+    Unused << Protocol::Send__delete__(this);
+    return IPC_OK();
+  }
+
+  typedef ipc::IProtocol::ActorDestroyReason Why;
+
+  void ActorDestroy(Why) override { DestroyIfNeeded(); }
+
+ protected:
+  void DestroyIfNeeded() {
+    if (!mDestroyed) {
+      Destroy();
+      mDestroyed = true;
+    }
+  }
+
+ private:
+  bool mDestroyed;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif