前言

承接上一节<4-11 client的信令逻辑>

从PeerConnectionClient::DoConnect开始。

PeerConnectionClient::DoConnect

该函数

void PeerConnectionClient::DoConnect() {
  // 创建控制control_socket，用于和服务器连接
  control_socket_.reset(CreateClientSocket(server_address_.ipaddr().family()));
   // 创建hanging socket，用于
  hanging_get_.reset(CreateClientSocket(server_address_.ipaddr().family()));
   // 初始化socket信号，里面是信号与槽函数的绑定
  InitSocketSignals();
  char buffer[1024];
  snprintf(buffer, sizeof(buffer), "GET /sign_in?%s HTTP/1.0\r\n\r\n",
           client_name_.c_str());
  onconnect_data_ = buffer;
  bool ret = ConnectControlSocket();
  if (ret)
    state_ = SIGNING_IN;
  if (!ret) {
    callback_->OnServerConnectionFailure();
  }
}

在此打断点，单击连接的时候，的堆栈如下

发送消息流程

当另一个client连接后，单击该client进行通信。就会调用MainWnd::QueueUIThreadCallback，发送消息到主线程去处理。

主线程接收后，是Conductor::UIThreadCallback处理。

void Conductor::UIThreadCallback(int msg_id, void* data) {
  switch (msg_id) {
    case PEER_CONNECTION_CLOSED: //对端关闭了
      RTC_LOG(INFO) << "PEER_CONNECTION_CLOSED";
      DeletePeerConnection();
      if (main_wnd_->IsWindow()) {
        if (client_->is_connected()) {
          main_wnd_->SwitchToPeerList(client_->peers());
        } else {
          main_wnd_->SwitchToConnectUI();
        }
      } else {
        DisconnectFromServer();
      }
      break;
    case SEND_MESSAGE_TO_PEER: { //发送消息到对端
      RTC_LOG(INFO) << "SEND_MESSAGE_TO_PEER";
      std::string* msg = reinterpret_cast<std::string*>(data);
      if (msg) {
        // For convenience, we always run the message through the queue.
        // This way we can be sure that messages are sent to the server
        // in the same order they were signaled without much hassle.
        pending_messages_.push_back(msg);
      }
      if (!pending_messages_.empty() && !client_->IsSendingMessage()) {
        msg = pending_messages_.front();
        pending_messages_.pop_front();
        if (!client_->SendToPeer(peer_id_, *msg) && peer_id_ != -1) {
          RTC_LOG(LS_ERROR) << "SendToPeer failed";
          DisconnectFromServer();
        }
        delete msg;
      }
      if (!peer_connection_.get())
        peer_id_ = -1;
      break;
    }
    case NEW_TRACK_ADDED: { // 新的视频通道
      auto* track = reinterpret_cast<webrtc::MediaStreamTrackInterface*>(data);
      if (track->kind() == webrtc::MediaStreamTrackInterface::kVideoKind) {
        auto* video_track = static_cast<webrtc::VideoTrackInterface*>(track);
        main_wnd_->StartRemoteRenderer(video_track);
      }
      track->Release();
      break;
    }
    case TRACK_REMOVED: {  // 对端停止发送了一个track
      // Remote peer stopped sending a track.
      auto* track = reinterpret_cast<webrtc::MediaStreamTrackInterface*>(data);
      track->Release();
      break;
    }
    default:
      RTC_NOTREACHED();
      break;
  }
}