PeerConnectionClient(二)之Win32Socket

Win32Socket类主要成员为：

EventSink是用来干嘛的呢，其实他主要是为了接收socket事件用的，从图中可看出，EventSink继承自Win32Window类，Win32Window类对应着一个MFC窗口，通过Windwos API:

WSAAPIWSAAsyncSelect(    _In_ SOCKET s,    _In_ HWND hWnd,    _In_ u_int wMsg,    _In_ long lEvent    );

将Win32Socket的socket事件注册，当消息到来时，hWnd句柄对应的窗口便能接收到该消息。
注册的代码在：

bool Win32Socket::SetAsync(int events) {  if (NULL == sink_) {    CreateSink();    ASSERT(NULL != sink_);  }  // start the async select  if (WSAAsyncSelect(socket_, sink_->handle(), WM_SOCKETNOTIFY, events)      == SOCKET_ERROR) {  //将socket_注册到sink_对应的窗口    UpdateLastError();    Close();    return false;  }  return true;}

消息处理函数在：

LRESULT Win32Window::WndProc(HWND hwnd, UINT uMsg,                             WPARAM wParam, LPARAM lParam) {  Win32Window* that = reinterpret_cast<Win32Window*>(      ::GetWindowLongPtr(hwnd, GWLP_USERDATA));  if (!that && (WM_CREATE == uMsg)) {    that->wnd_ = hwnd;  }  if (that) {    LRESULT result;    bool handled = that->OnMessage(uMsg, wParam, lParam, result);  //调用自己或派生类的OnMessage()  }  return ::DefWindowProc(hwnd, uMsg, wParam, lParam);}