mojo/system/message_in_transit_queue.h

   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
  32   bool IsEmpty() const {
  33     return queue_.empty();
  34   }
  35
  36   void AddMessage(scoped_ptr<MessageInTransit> message) {
  37     queue_.push_back(message.release());
  38   }
  39
  40   scoped_ptr<MessageInTransit> GetMessage() {
  41     MessageInTransit* rv = queue_.front();
  42     queue_.pop_front();
  43     return make_scoped_ptr(rv);
  44   }
  45
  46   MessageInTransit* PeekMessage() {
  47     return queue_.front();
  48   }
  49
  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_