wine之NtUserGetMessage

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参考:

wine.14
https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getmessage
函数作用：从调用此函数的消息队列中获取消息。

BOOL WINAPI NtUserGetMessage(MSG *msg, HWND hwnd, UINT first, UINT last)
{
  HANDLE server_queue = get_server_queue_handle();
  unsigned int mask = QS_POSTMESSAGE | QS_SENDMESSAGE;
  int ret;

  user_check_not_lock();
  check_for_driver_events(0);

  if(first || last)
  {
        if((fist <= WM_KEYLST) && (last >=WM_KEYFIRST)) mask |= QS_KEY;
        if(((first <= WM_MOUSELAST) && (last >= WM_MOUSEFIRST)) || ((first <= WM_NCMOUSELAST) && (last >= WM_NCMOUSEFIRST))) mask |= QS_MOUSE;
        if((first <= WM_TIMER) && (last >= WM_TIMER)) mask |= QS_TIMER;
        if((first <= WM_SYSTIMER) && (last >= WM_SYSTIMER)) mask |= QS_TIMER;
        if((first <= WM_PAINT) && (last >= WM_PAINT)) mask |= QS_PAINT;
  }
  else mask = QS_ALLINPUT;
  while(!(ret = peek_message(msg,hwnd, first, last, PM_REMOVE | (mask << 16), mask)))
  {
      wait_objects(1, &server_queue, INFINITE, mask & (QS_SENDMESSAGE | QS_SMRESULT), mask, 0);
  }
  if(ret < 0) return -1;
  check_for_driver_events(msg->message);

  return msg->message != WM_QUIT;
}

根据first与last 划定的范围设置不同的mask值，mask 值即表示需要在消息队列中获取什么消息。实际的查找是由函数peek_message 完成，当peek_message 返回0时，表示没有符合条件的消息，那么就需要调用函数wait_object来等待队列中出现满足条件的消息。

# 随笔