Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/messagehandler.h

@@ -0,0 +1,68 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_MESSAGEHANDLER_H_
+#define WEBRTC_BASE_MESSAGEHANDLER_H_
+
+#include "webrtc/base/constructormagic.h"
+
+namespace rtc {
+
+struct Message;
+
+// Messages get dispatched to a MessageHandler
+
+class MessageHandler {
+ public:
+  virtual ~MessageHandler();
+  virtual void OnMessage(Message* msg) = 0;
+
+ protected:
+  MessageHandler() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MessageHandler);
+};
+
+// Helper class to facilitate executing a functor on a thread.
+template <class ReturnT, class FunctorT>
+class FunctorMessageHandler : public MessageHandler {
+ public:
+  explicit FunctorMessageHandler(const FunctorT& functor)
+      : functor_(functor) {}
+  virtual void OnMessage(Message* msg) {
+    result_ = functor_();
+  }
+  const ReturnT& result() const { return result_; }
+
+ private:
+  FunctorT functor_;
+  ReturnT result_;
+};
+
+// Specialization for ReturnT of void.
+template <class FunctorT>
+class FunctorMessageHandler<void, FunctorT> : public MessageHandler {
+ public:
+  explicit FunctorMessageHandler(const FunctorT& functor)
+      : functor_(functor) {}
+  virtual void OnMessage(Message* msg) {
+    functor_();
+  }
+  void result() const {}
+
+ private:
+  FunctorT functor_;
+};
+
+
+} // namespace rtc
+
+#endif // WEBRTC_BASE_MESSAGEHANDLER_H_