src/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/basictypes.h"
  12 #include "base/callback_forward.h"
  13 #include "base/observer_list.h"
  14 #include "ui/gfx/win/window_impl.h"
  15
  16 template<typename T> struct DefaultSingletonTraits;
  17
  18 namespace gfx {
  19
  20 // Singleton message-only HWND that allows interested clients to receive WM_*
  21 // notifications.
  22 class GFX_EXPORT SingletonHwnd : public WindowImpl {
  23  public:
  24   static SingletonHwnd* GetInstance();
  25
  26   // Observer interface for receiving Windows WM_* notifications.
  27   class Observer {
  28    public:
  29     virtual void OnWndProc(HWND hwnd,
  30                            UINT message,
  31                            WPARAM wparam,
  32                            LPARAM lparam) = 0;
  33   };
  34
  35   // Add/remove observer to receive WM_* notifications.
  36   void AddObserver(Observer* observer);
  37   void RemoveObserver(Observer* observer);
  38
  39   // Windows callback for WM_* notifications.
  40   virtual BOOL ProcessWindowMessage(HWND window,
  41                                     UINT message,
  42                                     WPARAM wparam,
  43                                     LPARAM lparam,
  44                                     LRESULT& result,
  45                                     DWORD msg_map_id) override;
  46
  47  private:
  48   friend struct DefaultSingletonTraits<SingletonHwnd>;
  49
  50   SingletonHwnd();
  51   ~SingletonHwnd();
  52
  53   // List of registered observers.
  54   ObserverList<Observer> observer_list_;
  55
  56   DISALLOW_COPY_AND_ASSIGN(SingletonHwnd);
  57 };
  58
  59 }  // namespace gfx
  60
  61 #endif  // UI_GFX_WIN_SINGLETON_HWND_H_