Changed MessageReader so that it doesn't read from the socket if there are

remoting/protocol/message_decoder.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_PROTOCOL_MESSAGES_DECODER_H_
 #define REMOTING_PROTOCOL_MESSAGES_DECODER_H_
 
 #include <deque>
 #include <list>
 
@@ skipping 17 matching lines @@
 // message_data in bytes. message_data - content of the message.
 class MessageDecoder {
  public:
   MessageDecoder();
   virtual ~MessageDecoder();
 
   // Add next chunk of data. MessageDecoder retains |data| until all
   // its bytes are consumed.
   void AddData(scoped_refptr<net::IOBuffer> data, int data_size);
 
-  // Get next message from the stream and puts it in
-  // |message_buffer|. Returns false if there are no complete messages
-  // yet.
-  bool GetNextMessage(CompoundBuffer* message_buffer);
+  // Returns next message from the stream. Onnership of the result is
+  // passed to the caller. Returns NULL if there are no complete
+  // messages yet.

[awong, 2011/01/20 20:06:38]

Should we note somoewhere that each CompoundBuffer is guaranteed to only have 1
message?  Should there be a dcheck and/or unittest to verify this assertion
remains true?

[Alpha Left Google, 2011/01/20 20:54:52]

I don't think there's a simple DCHECK who can do this... :( It really relies how
we craft the compoundbuffer in this class.

[Sergey Ulanov, 2011/01/20 21:55:57]

Extended the comment a bit.
There are unittests for this (message_decoder_unittest,
message_reader_unittest). Also added DCHECK in ProtobufMessageReader.

+  CompoundBuffer* GetNextMessage();
 
  private:
   // Retrieves the read payload size of the current protocol buffer via |size|.
   // Returns false and leaves |size| unmodified, if we do not have enough data
   // to retrieve the current size.
   bool GetPayloadSize(int* size);
 
   CompoundBuffer buffer_;
 
   // |next_payload_| stores the size of the next payload if known.
   // |next_payload_known_| is true if the size of the next payload is known.
   // After one payload is read this is reset to false.
   int next_payload_;
   bool next_payload_known_;
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_MESSAGES_DECODER_H_