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      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 // This class replicates some menubar behaviors that are tricky to get right.
      6 // It is used to create a more native feel for the bookmark bar.
      7 
      8 #ifndef CHROME_BROWSER_UI_GTK_MENU_BAR_HELPER_H_
      9 #define CHROME_BROWSER_UI_GTK_MENU_BAR_HELPER_H_
     10 
     11 #include <gtk/gtk.h>
     12 
     13 #include <vector>
     14 
     15 #include "base/memory/scoped_ptr.h"
     16 #include "ui/base/gtk/gtk_signal.h"
     17 
     18 namespace ui {
     19 class GtkSignalRegistrar;
     20 }
     21 
     22 class MenuBarHelper {
     23  public:
     24   class Delegate {
     25    public:
     26     virtual ~Delegate() {}
     27 
     28     // Called when a the menu for a button ought to be triggered.
     29     virtual void PopupForButton(GtkWidget* button) = 0;
     30     virtual void PopupForButtonNextTo(GtkWidget* button,
     31                                       GtkMenuDirectionType dir) = 0;
     32   };
     33 
     34   // |delegate| cannot be null.
     35   explicit MenuBarHelper(Delegate* delegate);
     36   ~MenuBarHelper();
     37 
     38   // Must be called whenever a button's menu starts showing. It triggers the
     39   // MenuBarHelper to start listening for certain events.
     40   void MenuStartedShowing(GtkWidget* button, GtkWidget* menu);
     41 
     42   // Add |button| to the set of buttons we care about.
     43   void Add(GtkWidget* button);
     44 
     45   // Remove |button| from the set of buttons we care about.
     46   void Remove(GtkWidget* button);
     47 
     48   // Clear all buttons from the set.
     49   void Clear();
     50 
     51  private:
     52   CHROMEGTK_CALLBACK_0(MenuBarHelper, void, OnMenuHiddenOrDestroyed);
     53   CHROMEGTK_CALLBACK_1(MenuBarHelper, gboolean, OnMenuMotionNotify,
     54                        GdkEventMotion*);
     55   CHROMEGTK_CALLBACK_1(MenuBarHelper, void, OnMenuMoveCurrent,
     56                        GtkMenuDirectionType);
     57 
     58   // The buttons for which we pop up menus. We do not own these, or even add
     59   // refs to them.
     60   std::vector<GtkWidget*> buttons_;
     61 
     62   // The button that is currently showing a menu, or NULL.
     63   GtkWidget* button_showing_menu_;
     64 
     65   // The highest level menu that is currently showing, or NULL.
     66   GtkWidget* showing_menu_;
     67 
     68   // All the submenus of |showing_menu_|. We connect to motion events on all
     69   // of them.
     70   std::vector<GtkWidget*> submenus_;
     71 
     72   // Signal handlers that are attached only between the "show" and "hide" events
     73   // for the menu.
     74   scoped_ptr<ui::GtkSignalRegistrar> signal_handlers_;
     75 
     76   Delegate* delegate_;
     77 };
     78 
     79 #endif  // CHROME_BROWSER_UI_GTK_MENU_BAR_HELPER_H_
     80