[Chromoting] Introducing refcount-based life time management of the message loops in the service (d…

remoting/base/auto_message_loop.h

+// 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.
+
+#ifndef REMOTING_BASE_AUTO_MESSAGE_LOOP_H_
+#define REMOTING_BASE_AUTO_MESSAGE_LOOP_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
+#include "base/single_thread_task_runner.h"
+
+class MessageLoop;
+
+namespace remoting {
+
+// This class provides automatic life time management for a message loop.
+// The message loop is exited (i.e. Run() method exits) when the last reference
+// to |AutoMessageLoop| is dropped. |AutoMessageLoop| does not control the life
+// time of the message loop object.
+class AutoMessageLoop : public base::SingleThreadTaskRunner {
+ public:
+  // |message_loop| must outlive |AutoMessageLoop|.
+  explicit AutoMessageLoop(MessageLoop* message_loop);
+
+  // SingleThreadTaskRunner implementation
+  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
+                               const base::Closure& task,
+                               base::TimeDelta delay) OVERRIDE;
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task,
+      base::TimeDelta delay) OVERRIDE;
+  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
+
+ protected:
+  // Quits the message loop by posting MessageLoop::QuitClosure.
+  virtual void OnDestruct() const OVERRIDE;
+
+ private:
+  virtual ~AutoMessageLoop();
+
+  friend class base::DeleteHelper<AutoMessageLoop>;
+
+  MessageLoop* message_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(AutoMessageLoop);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_AUTO_MESSAGE_LOOP_H_