remoting/protocol/message_reader.h

   1 // Copyright (c) 2012 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 REMOTING_PROTOCOL_MESSAGE_READER_H_
   6 #define REMOTING_PROTOCOL_MESSAGE_READER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "base/threading/non_thread_safe.h"
  12 #include "remoting/base/compound_buffer.h"
  13 #include "remoting/protocol/message_decoder.h"
  14
  15 namespace net {
  16 class IOBuffer;
  17 class Socket;
  18 }  // namespace net
  19
  20 namespace remoting {
  21 namespace protocol {
  22
  23 // MessageReader reads data from the socket asynchronously and calls
  24 // callback for each message it receives. It stops calling the
  25 // callback as soon as the socket is closed, so the socket should
  26 // always be closed before the callback handler is destroyed.
  27 //
  28 // In order to throttle the stream, MessageReader doesn't try to read
  29 // new data from the socket until all previously received messages are
  30 // processed by the receiver (|done_task| is called for each message).
  31 // It is still possible that the MessageReceivedCallback is called
  32 // twice (so that there is more than one outstanding message),
  33 // e.g. when we the sender sends multiple messages in one TCP packet.
  34 class MessageReader : public base::NonThreadSafe {
  35  public:
  36   typedef base::Callback<void(scoped_ptr<CompoundBuffer>, const base::Closure&)>
  37       MessageReceivedCallback;
  38
  39   MessageReader();
  40   virtual ~MessageReader();
  41
  42   // Sets the callback to be called for each incoming message.
  43   void SetMessageReceivedCallback(const MessageReceivedCallback& callback);
  44
  45   // Starts reading from |socket|.
  46   void StartReading(net::Socket* socket);
  47
  48  private:
  49   void DoRead();
  50   void OnRead(int result);
  51   void HandleReadResult(int result);
  52   void OnDataReceived(net::IOBuffer* data, int data_size);
  53   void RunCallback(scoped_ptr<CompoundBuffer> message);
  54   void OnMessageDone();
  55
  56   net::Socket* socket_;
  57
  58   // Set to true, when we have a socket read pending, and expecting
  59   // OnRead() to be called when new data is received.
  60   bool read_pending_;
  61
  62   // Number of messages that we received, but haven't finished
  63   // processing yet, i.e. |done_task| hasn't been called for these
  64   // messages.
  65   int pending_messages_;
  66
  67   bool closed_;
  68   scoped_refptr<net::IOBuffer> read_buffer_;
  69
  70   MessageDecoder message_decoder_;
  71
  72   // Callback is called when a message is received.
  73   MessageReceivedCallback message_received_callback_;
  74
  75   base::WeakPtrFactory<MessageReader> weak_factory_;
  76
  77   DISALLOW_COPY_AND_ASSIGN(MessageReader);
  78 };
  79
  80 }  // namespace protocol
  81 }  // namespace remoting
  82
  83 #endif  // REMOTING_PROTOCOL_MESSAGE_READER_H_