1 /* 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef WEBRTC_BASE_MESSAGEHANDLER_H_ 12 #define WEBRTC_BASE_MESSAGEHANDLER_H_ 13 14 #include <utility> 15 16 #include "webrtc/base/constructormagic.h" 17 #include "webrtc/base/scoped_ptr.h" 18 19 namespace rtc { 20 21 struct Message; 22 23 // Messages get dispatched to a MessageHandler 24 25 class MessageHandler { 26 public: 27 virtual ~MessageHandler(); 28 virtual void OnMessage(Message* msg) = 0; 29 30 protected: MessageHandler()31 MessageHandler() {} 32 33 private: 34 RTC_DISALLOW_COPY_AND_ASSIGN(MessageHandler); 35 }; 36 37 // Helper class to facilitate executing a functor on a thread. 38 template <class ReturnT, class FunctorT> 39 class FunctorMessageHandler : public MessageHandler { 40 public: FunctorMessageHandler(const FunctorT & functor)41 explicit FunctorMessageHandler(const FunctorT& functor) 42 : functor_(functor) {} OnMessage(Message * msg)43 virtual void OnMessage(Message* msg) { 44 result_ = functor_(); 45 } result()46 const ReturnT& result() const { return result_; } 47 48 private: 49 FunctorT functor_; 50 ReturnT result_; 51 }; 52 53 // Specialization for rtc::scoped_ptr<ReturnT>. 54 template <class ReturnT, class FunctorT> 55 class FunctorMessageHandler<class rtc::scoped_ptr<ReturnT>, FunctorT> 56 : public MessageHandler { 57 public: FunctorMessageHandler(const FunctorT & functor)58 explicit FunctorMessageHandler(const FunctorT& functor) : functor_(functor) {} OnMessage(Message * msg)59 virtual void OnMessage(Message* msg) { result_ = std::move(functor_()); } result()60 rtc::scoped_ptr<ReturnT> result() { return std::move(result_); } 61 62 private: 63 FunctorT functor_; 64 rtc::scoped_ptr<ReturnT> result_; 65 }; 66 67 // Specialization for ReturnT of void. 68 template <class FunctorT> 69 class FunctorMessageHandler<void, FunctorT> : public MessageHandler { 70 public: FunctorMessageHandler(const FunctorT & functor)71 explicit FunctorMessageHandler(const FunctorT& functor) 72 : functor_(functor) {} OnMessage(Message * msg)73 virtual void OnMessage(Message* msg) { 74 functor_(); 75 } result()76 void result() const {} 77 78 private: 79 FunctorT functor_; 80 }; 81 82 } // namespace rtc 83 84 #endif // WEBRTC_BASE_MESSAGEHANDLER_H_ 85