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/webrtc/base/byteorder.h"
12
13 namespace remoting {
14 namespace protocol {
15
MessageDecoder()16 MessageDecoder::MessageDecoder()
17 : next_payload_(0),
18 next_payload_known_(false) {
19 }
20
~MessageDecoder()21 MessageDecoder::~MessageDecoder() {}
22
AddData(scoped_refptr<net::IOBuffer> data,int data_size)23 void MessageDecoder::AddData(scoped_refptr<net::IOBuffer> data,
24 int data_size) {
25 buffer_.Append(data.get(), data_size);
26 }
27
GetNextMessage()28 CompoundBuffer* 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
GetPayloadSize(int * size)53 bool 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 = rtc::GetBE32(header);
65 buffer_.CropFront(kHeaderSize);
66 return true;
67 }
68
69 } // namespace protocol
70 } // namespace remoting
71