前言

image.png
三大部分：
MainWin：处理界面相关内容，创建窗口，渲染界面，切换界面等；
conductor：调用native webrtc api，处理音视频通信；包括协调MainWin和peer_connection_client两部分工作。
peer_connection_client: 用于处理信令的发送接收

image.png

wWinMain入口函数

  1. int PASCAL wWinMain(HINSTANCE instance,
  2.                     HINSTANCE prev_instance,
  3.                     wchar_t* cmd_line,
  4.                     int cmd_show) {
  5.   // socket的初始化
  6.   rtc::WinsockInitializer winsock_init;
  7.   rtc::PhysicalSocketServer ss;
  8.   // 线程
  9.   rtc::AutoSocketServerThread main_thread(&ss);
  11.   // 命令行解析相关
  12.   WindowsCommandLineArguments win_args;
  13.   int argc = win_args.argc();
  14.   char** argv = win_args.argv();
  16.   absl::ParseCommandLine(argc, argv);
  18.   // InitFieldTrialsFromString stores the char*, so the char array must outlive
  19.   // the application.
  20.   const std::string forced_field_trials =
  21.       absl::GetFlag(FLAGS_force_fieldtrials);
  22.   webrtc::field_trial::InitFieldTrialsFromString(forced_field_trials.c_str());
  24.   // Abort if the user specifies a port that is outside the allowed
  25.   // range [1, 65535].
  26.   if ((absl::GetFlag(FLAGS_port) < 1) || (absl::GetFlag(FLAGS_port) > 65535)) {
  27.     printf("Error: %i is not a valid port.\n", absl::GetFlag(FLAGS_port));
  28.     return -1;
  29.   }
  31.   // 创建窗口
  32.   const std::string server = absl::GetFlag(FLAGS_server);
  33.   MainWnd wnd(server.c_str(), absl::GetFlag(FLAGS_port),
  34.               absl::GetFlag(FLAGS_autoconnect), absl::GetFlag(FLAGS_autocall));
  35.   // 注册窗口类，创建窗口，显示窗口
  36.   if (!wnd.Create()) {
  37.     RTC_DCHECK_NOTREACHED();
  38.     return -1;
  39.   }
  41.   // 初始化ssl
  42.   rtc::InitializeSSL();
  44.   // 创建PeerConnectionClient对象，用于处理信令发送接收
  45.   PeerConnectionClient client;
  47.   // 创建Conductor对象，协调PeerConnectionClient对象和主窗口wnd的工作
  48.   auto conductor = rtc::make_ref_counted<Conductor>(&client, &wnd);
  50.   // Main loop.
  51.   MSG msg;
  52.   BOOL gm;
  53.   while ((gm = ::GetMessage(&msg, NULL, 0, 0)) != 0 && gm != -1) {
  54.     if (!wnd.PreTranslateMessage(&msg)) {
  55.       ::TranslateMessage(&msg);
  56.       ::DispatchMessage(&msg);
  57.     }
  58.   }
  60.   // 客户端的关闭操作
  61.   if (conductor->connection_active() || client.is_connected()) {
  62.     while ((conductor->connection_active() || client.is_connected()) &&
  63.            (gm = ::GetMessage(&msg, NULL, 0, 0)) != 0 && gm != -1) {
  64.       if (!wnd.PreTranslateMessage(&msg)) {
  65.         ::TranslateMessage(&msg);
  66.         ::DispatchMessage(&msg);
  67.       }
  68.     }
  69.   }
  71.   // 清理ssl
  72.   rtc::CleanupSSL();
  73.   return 0;
  74. }

创建窗口

  1. bool MainWnd::Create() {
  2.   RTC_DCHECK(wnd_ == NULL);
  3.   // 注册窗口类
  4.   if (!RegisterWindowClass())
  5.     return false;
  7.   ui_thread_id_ = ::GetCurrentThreadId();
  8.   // 创建窗口
  9.   wnd_ =
  10.       ::CreateWindowExW(WS_EX_OVERLAPPEDWINDOW, kClassName, L"WebRTC",
  11.                         WS_OVERLAPPEDWINDOW | WS_VISIBLE | WS_CLIPCHILDREN,
  12.                         CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
  13.                         CW_USEDEFAULT, NULL, NULL, GetModuleHandle(NULL), this);
  15.   ::SendMessage(wnd_, WM_SETFONT, reinterpret_cast<WPARAM>(GetDefaultFont()),
  16.                 TRUE);
  18.   // 创建主窗口
  19.   CreateChildWindows();
  20.   // 切换到连接界面
  21.   SwitchToConnectUI();
  23.   return wnd_ != NULL;
  24. }
  26. bool MainWnd::RegisterWindowClass() {
  27.   if (wnd_class_)
  28.     return true;
  30.   WNDCLASSEXW wcex = {sizeof(WNDCLASSEX)};
  31.   wcex.style = CS_DBLCLKS;
  32.   wcex.hInstance = GetModuleHandle(NULL);
  33.   wcex.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_WINDOW + 1);
  34.   wcex.hCursor = ::LoadCursor(NULL, IDC_ARROW);
  35.   wcex.lpfnWndProc = &WndProc; // 绑定消息处理
  36.   wcex.lpszClassName = kClassName;
  37.   wnd_class_ = ::RegisterClassExW(&wcex);
  38.   RTC_DCHECK(wnd_class_ != 0);
  39.   return wnd_class_ != 0;
  40. }
  42. void MainWnd::SwitchToConnectUI() {
  43.   RTC_DCHECK(IsWindow());
  44.   // 隐藏连接列表
  45.   LayoutPeerListUI(false);
  46.   ui_ = CONNECT_TO_SERVER;
  47.   // 显示连接界面
  48.   LayoutConnectUI(true);
  49.   ::SetFocus(edit1_);
  51.   if (auto_connect_)
  52.     ::PostMessage(button_, BM_CLICK, 0, 0);
  53. }

处理消息

  1. LRESULT CALLBACK MainWnd::WndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp) {
  2.   MainWnd* me =
  3.       reinterpret_cast<MainWnd*>(::GetWindowLongPtr(hwnd, GWLP_USERDATA));
  4.   if (!me && WM_CREATE == msg) {
  5.     CREATESTRUCT* cs = reinterpret_cast<CREATESTRUCT*>(lp);
  6.     me = reinterpret_cast<MainWnd*>(cs->lpCreateParams);
  7.     me->wnd_ = hwnd;
  8.     ::SetWindowLongPtr(hwnd, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(me));
  9.   }
  11.   LRESULT result = 0;
  12.   if (me) {
  13.     void* prev_nested_msg = me->nested_msg_;
  14.     me->nested_msg_ = &msg;
  16.     bool handled = me->OnMessage(msg, wp, lp, &result);
  17.     if (WM_NCDESTROY == msg) {
  18.       me->destroyed_ = true;
  19.     } else if (!handled) {
  20.       result = ::DefWindowProc(hwnd, msg, wp, lp);
  21.     }
  23.     if (me->destroyed_ && prev_nested_msg == NULL) {
  24.       me->OnDestroyed();
  25.       me->wnd_ = NULL;
  26.       me->destroyed_ = false;
  27.     }
  29.     me->nested_msg_ = prev_nested_msg;
  30.   } else {
  31.     result = ::DefWindowProc(hwnd, msg, wp, lp);
  32.   }
  34.   return result;
  35. }

后面都是调用到OnMessage函数处理。
bool MainWnd::OnMessage(UINT msg, WPARAM wp, LPARAM lp, LRESULT* result)

image.png