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#include "remoting/protocol/message_decoder.h"
6
7#include "base/logging.h"
8#include "net/base/io_buffer.h"
9#include "remoting/base/compound_buffer.h"
10#include "remoting/proto/internal.pb.h"
11#include "third_party/libjingle/source/talk/base/byteorder.h"
12
13namespace remoting {
14namespace protocol {
15
16MessageDecoder::MessageDecoder()
17    : next_payload_(0),
18      next_payload_known_(false) {
19}
20
21MessageDecoder::~MessageDecoder() {}
22
23void MessageDecoder::AddData(scoped_refptr<net::IOBuffer> data,
24                             int data_size) {
25  buffer_.Append(data.get(), data_size);
26}
27
28CompoundBuffer* MessageDecoder::GetNextMessage() {
29  // Determine the payload size. If we already know it then skip this part.
30  // We may not have enough data to determine the payload size so use a
31  // utility function to find out.
32  int next_payload = -1;
33  if (!next_payload_known_ && GetPayloadSize(&next_payload)) {
34    DCHECK_NE(-1, next_payload);
35    next_payload_ = next_payload;
36    next_payload_known_ = true;
37  }
38
39  // If the next payload size is still not known or we don't have enough
40  // data for parsing then exit.
41  if (!next_payload_known_ || buffer_.total_bytes() < next_payload_)
42    return NULL;
43
44  CompoundBuffer* message_buffer = new CompoundBuffer();
45  message_buffer->CopyFrom(buffer_, 0, next_payload_);
46  message_buffer->Lock();
47  buffer_.CropFront(next_payload_);
48  next_payload_known_ = false;
49
50  return message_buffer;
51}
52
53bool MessageDecoder::GetPayloadSize(int* size) {
54  // The header has a size of 4 bytes.
55  const int kHeaderSize = sizeof(int32);
56
57  if (buffer_.total_bytes() < kHeaderSize)
58    return false;
59
60  CompoundBuffer header_buffer;
61  char header[kHeaderSize];
62  header_buffer.CopyFrom(buffer_, 0, kHeaderSize);
63  header_buffer.CopyTo(header, kHeaderSize);
64  *size = talk_base::GetBE32(header);
65  buffer_.CropFront(kHeaderSize);
66  return true;
67}
68
69}  // namespace protocol
70}  // namespace remoting
71