gfx/layers/IPDLActor.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef MOZILLA_LAYERS_IPDLACTOR_H
   8 #define MOZILLA_LAYERS_IPDLACTOR_H
   9
  10 #include "mozilla/ipc/ProtocolUtils.h"
  11 #include "mozilla/layers/CompositableForwarder.h"
  12 #include "mozilla/Unused.h"
  13 #include "gfxPlatform.h"
  14
  15 namespace mozilla {
  16 namespace layers {
  17
  18 /// A base class to facilitate the deallocation of IPDL actors.
  19 ///
  20 /// Implements the parent side of the simple deallocation handshake.
  21 /// Override the Destroy method rather than the ActorDestroy method.
  22 template <typename Protocol>
  23 class ParentActor : public Protocol {
  24  public:
  25   ParentActor() : mDestroyed(false) {}
  26
  27   ~ParentActor() { MOZ_ASSERT(mDestroyed); }
  28
  29   bool CanSend() const { return !mDestroyed; }
  30
  31   // Override this rather than ActorDestroy
  32   virtual void Destroy() {}
  33
  34   mozilla::ipc::IPCResult RecvDestroy() final {
  35     DestroyIfNeeded();
  36     Unused << Protocol::Send__delete__(this);
  37     return IPC_OK();
  38   }
  39
  40   typedef ipc::IProtocol::ActorDestroyReason Why;
  41
  42   void ActorDestroy(Why) override { DestroyIfNeeded(); }
  43
  44  protected:
  45   void DestroyIfNeeded() {
  46     if (!mDestroyed) {
  47       Destroy();
  48       mDestroyed = true;
  49     }
  50   }
  51
  52  private:
  53   bool mDestroyed;
  54 };
  55
  56 }  // namespace layers
  57 }  // namespace mozilla
  58
  59 #endif