1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef MOJO_SYSTEM_MESSAGE_QUEUE_H_ 6 #define MOJO_SYSTEM_MESSAGE_QUEUE_H_ 7 8 #include <deque> 9 10 #include "base/macros.h" 11 #include "base/memory/scoped_ptr.h" 12 #include "mojo/system/message_in_transit.h" 13 #include "mojo/system/system_impl_export.h" 14 15 namespace mojo { 16 namespace system { 17 18 // A simple queue for |MessageInTransit|s (that owns its messages). 19 // This class is not thread-safe. 20 // TODO(vtl): Write tests. 21 class MOJO_SYSTEM_IMPL_EXPORT MessageInTransitQueue { 22 public: 23 MessageInTransitQueue(); 24 25 struct PassContents {}; 26 // Constructor that takes over the contents of another 27 // |MessageInTransitQueue|, leaving it empty. 28 MessageInTransitQueue(PassContents, MessageInTransitQueue* other); 29 30 ~MessageInTransitQueue(); 31 IsEmpty()32 bool IsEmpty() const { 33 return queue_.empty(); 34 } 35 AddMessage(scoped_ptr<MessageInTransit> message)36 void AddMessage(scoped_ptr<MessageInTransit> message) { 37 queue_.push_back(message.release()); 38 } 39 GetMessage()40 scoped_ptr<MessageInTransit> GetMessage() { 41 MessageInTransit* rv = queue_.front(); 42 queue_.pop_front(); 43 return make_scoped_ptr(rv); 44 } 45 PeekMessage()46 MessageInTransit* PeekMessage() { 47 return queue_.front(); 48 } 49 DiscardMessage()50 void DiscardMessage() { 51 delete queue_.front(); 52 queue_.pop_front(); 53 } 54 55 void Clear(); 56 57 private: 58 // TODO(vtl): When C++11 is available, switch this to a deque of 59 // |scoped_ptr|/|unique_ptr|s. 60 std::deque<MessageInTransit*> queue_; 61 62 DISALLOW_COPY_AND_ASSIGN(MessageInTransitQueue); 63 }; 64 65 66 } // namespace system 67 } // namespace mojo 68 69 #endif // MOJO_SYSTEM_MESSAGE_QUEUE_H_ 70