blob: 659c68b6086dfd98a3c89b2eb5e37c8433d1f49e [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/memory/ref_counted.h"
#include "base/message_loop.h"
#include "base/message_loop_proxy.h"
namespace base {
class WaitableEvent;
namespace media {
// A common base class for AudioOutputDevice and AudioInputDevice that manages
// a message loop pointer and monitors it for destruction. If the object goes
// out of scope before the message loop, the object will automatically remove
// itself from the message loop's list of destruction observers.
// NOTE: The class that inherits from this class must implement the
// WillDestroyCurrentMessageLoop virtual method from DestructionObserver.
class ScopedLoopObserver
: public MessageLoop::DestructionObserver {
explicit ScopedLoopObserver(
const scoped_refptr<base::MessageLoopProxy>& message_loop);
virtual ~ScopedLoopObserver();
// Accessor to the loop that's used by the derived class.
const scoped_refptr<base::MessageLoopProxy>& message_loop() { return loop_; }
// Call to add or remove ourselves from the list of destruction observers for
// the message loop.
void ObserveLoopDestruction(bool enable, base::WaitableEvent* done);
// A pointer to the message loop's proxy. In case the loop gets destroyed
// before this object goes out of scope, PostTask etc will fail but not crash.
scoped_refptr<base::MessageLoopProxy> loop_;
} // namespace media.