1 files changed, 146 insertions, 0 deletions
diff --git a/remoting/protocol/messages_decoder.cc b/remoting/protocol/messages_decoder.cc
new file mode 100644
index 0000000..f7c7439
--- /dev/null
+++ b/remoting/protocol/messages_decoder.cc
@@ -0,0 +1,146 @@
+// 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.
+
+#include "remoting/protocol/messages_decoder.h"
+
+#include "base/logging.h"
+#include "remoting/base/multiple_array_input_stream.h"
+#include "talk/base/byteorder.h"
+
+namespace remoting {
+
+MessagesDecoder::MessagesDecoder()
+    : last_read_position_(0),
+      available_bytes_(0),
+      next_payload_(0),
+      next_payload_known_(false) {
+}
+
+MessagesDecoder::~MessagesDecoder() {}
+
+void MessagesDecoder::ParseClientMessages(scoped_refptr<net::IOBuffer> data,
+                                          int data_size,
+                                          ClientMessageList* messages) {
+  ParseMessages<ChromotingClientMessage>(data, data_size, messages);
+}
+
+void MessagesDecoder::ParseHostMessages(scoped_refptr<net::IOBuffer> data,
+                                        int data_size,
+                                        HostMessageList* messages) {
+  ParseMessages<ChromotingHostMessage>(data, data_size, messages);
+}
+
+template <typename T>
+void MessagesDecoder::ParseMessages(scoped_refptr<net::IOBuffer> data,
+                                    int data_size,
+                                    std::list<T*>* messages) {
+  // If this is the first data in the processing queue, then set the
+  // last read position to 0.
+  if (data_list_.empty())
+    last_read_position_ = 0;
+
+  // First enqueue the data received.
+  data_list_.push_back(DataChunk(data, data_size));
+  available_bytes_ += data_size;
+
+  // Then try to parse one message until we can't parse anymore.
+  T* message;
+  while (ParseOneMessage<T>(&message)) {
+    messages->push_back(message);
+  }
+}
+
+template <typename T>
+bool MessagesDecoder::ParseOneMessage(T** message) {
+  // Determine the payload size. If we already know it, then skip this
+  // part.
+  // We have the value set to -1 for checking later.
+  int next_payload = -1;
+  if (!next_payload_known_ && GetPayloadSize(&next_payload)) {
+    DCHECK_NE(-1, next_payload);
+    next_payload_ = next_payload;
+    next_payload_known_ = true;
+  }
+
+  // If the next payload size is still not known or we don't have enough
+  // data for parsing then exit.
+  if (!next_payload_known_ || available_bytes_ < next_payload_)
+    return false;
+  next_payload_known_ = false;
+
+  // Create a MultipleArrayInputStream for parsing.
+  MultipleArrayInputStream stream;
+  std::vector<scoped_refptr<net::IOBuffer> > buffers;
+  while (next_payload_ > 0 && !data_list_.empty()) {
+    DataChunk* buffer = &(data_list_.front());
+    size_t read_bytes = std::min(buffer->data_size - last_read_position_,
+                                 next_payload_);
+
+    buffers.push_back(buffer->data);
+    stream.AddBuffer(buffer->data->data() + last_read_position_, read_bytes);
+
+    // Adjust counters.
+    last_read_position_ += read_bytes;
+    next_payload_ -= read_bytes;
+    available_bytes_ -= read_bytes;
+
+    // If the front buffer is fully read, remove it from the queue.
+    if (buffer->data_size == last_read_position_) {
+      data_list_.pop_front();
+      last_read_position_ = 0;
+    }
+  }
+  DCHECK_EQ(0UL, next_payload_);
+
+  // And finally it is parsing.
+  *message = new T();
+  bool ret = (*message)->ParseFromZeroCopyStream(&stream);
+  if (!ret) {
+    LOG(ERROR) << "Received invalid message.";
+    delete *message;
+  }
+  return ret;
+}
+
+bool MessagesDecoder::GetPayloadSize(int* size) {
+  // The header has a size of 4 bytes.
+  const size_t kHeaderSize = sizeof(int32);
+
+  if (available_bytes_ < kHeaderSize)
+    return false;
+
+  std::string header;
+  while (header.length() < kHeaderSize && !data_list_.empty()) {
+    DataChunk* buffer = &(data_list_.front());
+
+    // Find out how many bytes we need and how many bytes are available in this
+    // buffer.
+    int needed_bytes = kHeaderSize - header.length();
+    int available_bytes = buffer->data_size - last_read_position_;
+
+    // Then append the required bytes into the header and advance the last
+    // read position.
+    int read_bytes = std::min(needed_bytes, available_bytes);
+    header.append(
+        reinterpret_cast<char*>(buffer->data->data()) + last_read_position_,
+        read_bytes);
+    last_read_position_ += read_bytes;
+    available_bytes_ -= read_bytes;
+
+    // If the buffer is depleted then remove it from the queue.
+    if (last_read_position_ == buffer->data_size) {
+      last_read_position_ = 0;
+      data_list_.pop_front();
+    }
+  }
+
+  if (header.length() == kHeaderSize) {
+    *size = talk_base::GetBE32(header.c_str());
+    return true;
+  }
+  NOTREACHED() << "Unable to extract payload size";
+  return false;
+}
+
+}  // namespace remoting