GMPCrashHelperHolder.h

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/* -*- Mode: C++; tab-width: 2; 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/. */

#ifndef GMPCrashHelperHolder_h_

#define GMPCrashHelperHolder_h_

#include "mozilla/RefPtr.h"

#include "GMPCrashHelper.h"

namespace mozilla {

// Disconnecting the GMPCrashHelpers at the right time is hard. We need to

// ensure that in the crashing case that we stay connected until the

// "gmp-plugin-crashed" message is processed in the content process.

//

// We have two channels connecting to the GMP; PGMP which connects from

// chrome to GMP process, and PGMPContent, which bridges between the content

// and GMP process. If the GMP crashes both PGMP and PGMPContent receive

// ActorDestroy messages and begin to shutdown at the same time.

//

// However the crash report mini dump must be generated in the chrome

// process' ActorDestroy, before the "gmp-plugin-crashed" message can be sent

// to the content process. We fire the "PluginCrashed" event when we handle

// the "gmp-plugin-crashed" message in the content process, and we need the

// crash helpers to do that.

//

// The PGMPContent's managed actors' ActorDestroy messages are the only shutdown

// notification we get in the content process, but we can't disconnect the

// crash handlers there in the crashing case, as ActorDestroy happens before

// we've received the "gmp-plugin-crashed" message and had a chance for the

// crash helpers to generate the window to dispatch PluginCrashed to initiate

// the crash report submission notification box.

//

// So we need to ensure that in the content process, the GMPCrashHelpers stay

// connected to the GMPService until after ActorDestroy messages are received

// if there's an abnormal shutdown. In the case where the GMP doesn't crash,

// we do actually want to disconnect GMPCrashHandlers in ActorDestroy, since

// we don't have any other signal that a GMP actor is shutting down. If we don't

// disconnect the crash helper there in the normal shutdown case, the helper

// will stick around forever and leak.

//

// In the crashing case, the GMPCrashHelpers are deallocated when the crash

// report is processed in GeckoMediaPluginService::RunPluginCrashCallbacks().

//

// It's a bit yuck that we have to have two paths for disconnecting the crash

// helpers, but there aren't really any better options.

class GMPCrashHelperHolder {

 public:

  void SetCrashHelper(GMPCrashHelper* aHelper);

  GMPCrashHelper* GetCrashHelper();

  void MaybeDisconnect(bool aAbnormalShutdown);

 private:

  RefPtr<GMPCrashHelper> mCrashHelper;

};

}  // namespace mozilla

#endif  // GMPCrashHelperHolder_h_