Introducing remoting::Stoppable helper base class implementing asynchronous shutdown on a specific t

remoting/base/stoppable.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_STOPPABLE_H_
+#define REMOTING_BASE_STOPPABLE_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}  // namespace base
+
+namespace remoting {
+
+// A helper base class that implements asynchronous shutdown on a specific
+// thread.
+class Stoppable {
+ public:
+  // Constructs an object and stores the callback to be posted to |task_runner|
+  // once the object has been shutdown completely.
+  explicit Stoppable(scoped_refptr<base::SingleThreadTaskRunner> task_runner,

[Wez, 2012/08/18 01:08:29]

This doesn't need to be explicit, does it?

[alexeypa (please no reviews), 2012/08/18 01:25:35]

Yes, you are right. It should not be explicit. I'll fix it in one of the
upcoming CLs.

+                     const base::Closure& stopped_callback);
+  virtual ~Stoppable();
+
+  // Initiates shutdown. It can be called by both the owner of the object and
+  // the object itself resulting in the same shutdown sequence.
+  void Stop();
+
+ protected:
+  // Called by derived classes to notify about shutdown completion. Posts
+  // the completion task on |task_runner_| message loop.
+  void CompleteStopping();
+
+  // Derived classes have to override this method to implement the shutdown
+  // logic.
+  virtual void DoStop() = 0;
+
+  enum State {
+    kRunning,
+    kStopping,
+    kStopped
+  };
+
+  State stoppable_state() const { return state_; }
+
+ private:
+  State state_;
+
+  // A callback to be called when shutdown is completed.
+  base::Closure stopped_callback_;
+
+  // The target task runner where the shutdown notification will be posted.
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(Stoppable);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_STOPPABLE_H_