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

remoting/base/auto_thread.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_THREAD_H_
+#define REMOTING_BASE_AUTO_THREAD_H_
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread.h"
+
+class MessageLoop;
+
+namespace remoting {
+
+// This class provides automatic life time management for a thread running
+// a message loop. The thread is stopped when the last reference to |AutoThread|
+// is dropped. |AutoThread| is deleted from a a task running on the parent
+// message loop.
+class AutoThread : public base::SingleThreadTaskRunner {
+ public:
+  AutoThread(
+      const char* name,
+      scoped_refptr<base::SingleThreadTaskRunner> parent);

[Wez, 2012/08/24 21:30:49]

I don't really see the point of this class; why can't you start a Thread, wrap
it with an AutoMessageLoop to cause it to exit when no-one needs it any more,
and then just join it in the caller when you absolutely positively have to? 
What does this class actually provide beyond that?

[alexeypa (please no reviews), 2012/08/27 21:19:40]

MessageLoop and Thread should be stopped differently. That's why two separate
classes were needed.

+
+  // A backdoor to the enclosed message loop for the cases when an external
+  // interface does not take |base::SingleThreadTaskRunner|.
+  MessageLoop* message_loop() { return thread_.message_loop(); }
+
+  // Wrappers around the corresponding methods of |base::Thread|.
+  bool Start();
+  bool StartWithOptions(const base::Thread::Options& options);
+
+  // 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:
+  // Stops the thread and deletes itself.
+  virtual void OnDestruct() const OVERRIDE;
+
+ private:
+  virtual ~AutoThread();
+
+  friend class base::DeleteHelper<AutoThread>;
+
+  // The parent task runner that will be used to destroy |this|.
+  scoped_refptr<base::SingleThreadTaskRunner> parent_;
+
+  // The wrapped thread object.
+  base::Thread thread_;
+
+  DISALLOW_COPY_AND_ASSIGN(AutoThread);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_AUTO_THREAD_H_