ui/gfx/win/singleton_hwnd.h

   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 #ifndef UI_GFX_WIN_SINGLETON_HWND_H_
   6 #define UI_GFX_WIN_SINGLETON_HWND_H_
   7
   8 #include <windows.h>
   9 #include <vector>
  10
  11 #include "base/observer_list.h"
  12 #include "ui/gfx/gfx_export.h"
  13 #include "ui/gfx/win/window_impl.h"
  14
  15 namespace base {
  16 template<typename T> struct DefaultSingletonTraits;
  17 }
  18
  19 namespace gfx {
  20
  21 class SingletonHwndObserver;
  22
  23 // Singleton message-only HWND that allows interested clients to receive WM_*
  24 // notifications.
  25 class GFX_EXPORT SingletonHwnd : public WindowImpl {
  26  public:
  27   static SingletonHwnd* GetInstance();
  28
  29   // Windows callback for WM_* notifications.
  30   BOOL ProcessWindowMessage(HWND window,
  31                             UINT message,
  32                             WPARAM wparam,
  33                             LPARAM lparam,
  34                             LRESULT& result,
  35                             DWORD msg_map_id) override;
  36
  37  private:
  38   friend class SingletonHwndObserver;
  39   friend struct base::DefaultSingletonTraits<SingletonHwnd>;
  40
  41   SingletonHwnd();
  42   ~SingletonHwnd() override;
  43
  44   // Add/remove SingletonHwndObserver to forward WM_* notifications.
  45   void AddObserver(SingletonHwndObserver* observer);
  46   void RemoveObserver(SingletonHwndObserver* observer);
  47
  48   // List of registered observers.
  49   base::ObserverList<SingletonHwndObserver, true> observer_list_;
  50
  51   DISALLOW_COPY_AND_ASSIGN(SingletonHwnd);
  52 };
  53
  54 }  // namespace gfx
  55
  56 #endif  // UI_GFX_WIN_SINGLETON_HWND_H_