ui/base/win/foreground_helper.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/base/win/foreground_helper.h"
   6
   7 #include "base/logging.h"
   8 #include "ui/gfx/win/window_impl.h"
   9
  10 namespace ui {
  11
  12 // static
  13 HRESULT ForegroundHelper::SetForeground(HWND window) {
  14   DCHECK(::IsWindow(window));
  15   ForegroundHelper foreground_helper;
  16   return foreground_helper.ForegroundHotKey(window);
  17 }
  18
  19 HRESULT ForegroundHelper::ForegroundHotKey(HWND window) {
  20   // This implementation registers a hot key (F22) and then
  21   // triggers the hot key.  When receiving the hot key, we'll
  22   // be in the foreground and allowed to move the target window
  23   // into the foreground too.
  24
  25   set_window_style(WS_POPUP);
  26   Init(NULL, gfx::Rect());
  27
  28   static const int kHotKeyId = 0x0000baba;
  29   static const int kHotKeyWaitTimeout = 2000;
  30
  31   // Store the target window into our USERDATA for use in our
  32   // HotKey handler.
  33   window_ = window;
  34   RegisterHotKey(hwnd(), kHotKeyId, 0, VK_F22);
  35
  36   // If the calling thread is not yet a UI thread, call PeekMessage
  37   // to ensure creation of its message queue.
  38   MSG msg = {0};
  39   PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE);
  40
  41   // Send the Hotkey.
  42   INPUT hotkey = {0};
  43   hotkey.type = INPUT_KEYBOARD;
  44   hotkey.ki.wVk =  VK_F22;
  45   if (1 != SendInput(1, &hotkey, sizeof(hotkey))) {
  46     LOG(WARNING) << "Failed to send input; GetLastError(): " << GetLastError();
  47     return E_FAIL;
  48   }
  49
  50   // There are scenarios where the WM_HOTKEY is not dispatched by the
  51   // the corresponding foreground thread. To prevent us from indefinitely
  52   // waiting for the hotkey, we set a timer and exit the loop.
  53   SetTimer(hwnd(), kHotKeyId, kHotKeyWaitTimeout, NULL);
  54
  55   // Loop until we get the key or the timer fires.
  56   while (GetMessage(&msg, NULL, 0, 0)) {
  57     TranslateMessage(&msg);
  58     DispatchMessage(&msg);
  59
  60     if (WM_HOTKEY == msg.message)
  61       break;
  62     if (WM_TIMER == msg.message) {
  63       SetForegroundWindow(window);
  64       break;
  65     }
  66   }
  67
  68   UnregisterHotKey(hwnd(), kHotKeyId);
  69   KillTimer(hwnd(), kHotKeyId);
  70   DestroyWindow(hwnd());
  71
  72   return S_OK;
  73 }
  74
  75 // Handle the registered Hotkey being pressed.
  76 void ForegroundHelper::OnHotKey(int id, UINT vcode, UINT modifiers) {
  77   SetForegroundWindow(window_);
  78 }
  79
  80 }  // namespace ui