// Copyright (c) 2012 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_MESSAGE_DECODER_H_
#define REMOTING_PROTOCOL_MESSAGE_DECODER_H_
#include <deque>
#include <list>
#include "base/memory/ref_counted.h"
#include "net/base/io_buffer.h"
#include "remoting/base/compound_buffer.h"
#if defined(USE_SYSTEM_PROTOBUF)
#include <google/protobuf/message_lite.h>
#else
#include "third_party/protobuf/src/google/protobuf/message_lite.h"
#endif
namespace remoting {
namespace protocol {
// MessageDecoder uses CompoundBuffer to split the data received from
// the network into separate messages. Each message is expected to be
// decoded in the stream as follows:
// +--------------+--------------+
// | message_size | message_data |
// +--------------+--------------+
//
// Here, message_size is 4-byte integer that represents size of
// 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);
// Returns next message from the stream. Ownership of the result is
// passed to the caller. Returns NULL if there are no complete
// messages yet, otherwise returns a buffer that contains one
// message.
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_MESSAGE_DECODER_H_