ui/views/widget/child_window_message_processor.h

   1 // Copyright (c) 2011 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_VIEWS_WIDGET_CHILD_WINDOW_MESSAGE_PROCESSOR_H_
   6 #define UI_VIEWS_WIDGET_CHILD_WINDOW_MESSAGE_PROCESSOR_H_
   7
   8 #include <windows.h>
   9
  10 namespace ui {
  11 class ViewProp;
  12 }
  13
  14 namespace views {
  15
  16 // Windows sends a handful of messages to the parent window rather than the
  17 // window itself. For example, selection changes of a rich edit (EN_SELCHANGE)
  18 // are sent to the parent, not the window. Typically such message are best
  19 // dealt with by the window rather than the parent. NativeWidgetWin allows for
  20 // registering a ChildWindowMessageProcessor to handle such messages.
  21 class ChildWindowMessageProcessor {
  22  public:
  23   // Registers |processor| for |hwnd|. The caller takes ownership of the
  24   // returned object.
  25   static ui::ViewProp* Register(HWND hwnd,
  26                                  ChildWindowMessageProcessor* processor);
  27
  28   // Returns the ChildWindowMessageProcessor for |hwnd|, NULL if there isn't
  29   // one.
  30   static ChildWindowMessageProcessor* Get(HWND hwnd);
  31
  32   // Invoked for any messages that are sent to the parent and originated from
  33   // the HWND this ChildWindowMessageProcessor was registered for. Returns true
  34   // if the message was handled with a valid result in |result|. Returns false
  35   // if the message was not handled.
  36   virtual bool ProcessMessage(UINT message,
  37                               WPARAM w_param,
  38                               LPARAM l_param,
  39                               LRESULT* result) = 0;
  40
  41  protected:
  42   virtual ~ChildWindowMessageProcessor() {}
  43 };
  44
  45 }  // namespace views
  46
  47 #endif  // UI_VIEWS_WIDGET_CHILD_WINDOW_MESSAGE_PROCESSOR_H_