a11y: Simplify GtkNotebookAccessible

Let the GtkNotebook explicitly update the accessible object that the
current page has changed, instead of overriding
GtkWidgetAccessible.notify_gtk.

gtk/a11y/gtknotebookaccessible.c

@@ -17,10 +17,12 @@
 
 #include "config.h"
 
-#include <string.h>
-#include <gtk/gtk.h>
-#include "gtknotebookaccessible.h"
+#include "gtknotebookaccessibleprivate.h"
+
 #include "gtknotebookpageaccessible.h"
+#include "gtknotebook.h"
+
+#include <string.h>
 
 struct _GtkNotebookAccessiblePrivate
 {
@@ -153,30 +155,17 @@ gtk_notebook_accessible_ref_child (AtkObject *obj,
   return child;
 }
 
-static void
-gtk_notebook_accessible_notify_gtk (GObject    *obj,
-                                    GParamSpec *pspec)
+void
+gtk_notebook_accessible_update_page (GtkNotebookAccessible *self,
+                                     int                    page_num)
 {
-  GtkWidget *widget;
-  AtkObject* atk_obj;
+  GtkNotebookAccessiblePrivate *priv = gtk_notebook_accessible_get_instance_private (self);
+  AtkObject *atk_obj = ATK_OBJECT (self);
+  int old_page_num = priv->selected_page;
 
-  widget = GTK_WIDGET (obj);
-  atk_obj = gtk_widget_get_accessible (widget);
-
-  if (strcmp (pspec->name, "page") == 0)
-    {
-      gint page_num, old_page_num;
-      GtkNotebookAccessible *accessible;
-      GtkNotebook *notebook;
-
-      accessible = GTK_NOTEBOOK_ACCESSIBLE (atk_obj);
-      notebook = GTK_NOTEBOOK (widget);
+  priv->selected_page = page_num;
 
   /* Notify SELECTED state change for old and new page */
-      old_page_num = accessible->priv->selected_page;
-      page_num = gtk_notebook_get_current_page (notebook);
-      accessible->priv->selected_page = page_num;
-
   if (page_num != old_page_num)
     {
       AtkObject *child;
@@ -184,25 +173,24 @@ gtk_notebook_accessible_notify_gtk (GObject    *obj,
       if (old_page_num != -1)
         {
           child = gtk_notebook_accessible_ref_child (atk_obj, old_page_num);
-              if (child)
+          if (child != NULL)
             {
               atk_object_notify_state_change (child, ATK_STATE_SELECTED, FALSE);
               g_object_unref (child);
             }
         }
+
       child = gtk_notebook_accessible_ref_child (atk_obj, page_num);
-          if (child)
+      if (child != NULL)
         {
           atk_object_notify_state_change (child, ATK_STATE_SELECTED, TRUE);
           g_object_unref (child);
         }
+
       g_signal_emit_by_name (atk_obj, "selection-changed");
       g_signal_emit_by_name (atk_obj, "visible-data-changed");
     }
 }
-  else
-    GTK_WIDGET_ACCESSIBLE_CLASS (gtk_notebook_accessible_parent_class)->notify_gtk (obj, pspec);
-}
 
 /*
  * GtkNotebook only supports the selection of one page at a time.
@@ -230,14 +218,11 @@ gtk_notebook_accessible_class_init (GtkNotebookAccessibleClass *klass)
 {
   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
   AtkObjectClass  *class = ATK_OBJECT_CLASS (klass);
-  GtkWidgetAccessibleClass *widget_class = (GtkWidgetAccessibleClass*)klass;
 
   gobject_class->finalize = gtk_notebook_accessible_finalize;
 
   class->ref_child = gtk_notebook_accessible_ref_child;
   class->initialize = gtk_notebook_accessible_initialize;
-
-  widget_class->notify_gtk = gtk_notebook_accessible_notify_gtk;
 }
 
 static void

gtk/a11y/gtknotebookaccessibleprivate.h

@@ -0,0 +1,30 @@
+/* gtknotebookaccessibleprivate.h: GtkNotebookAccessible private API
+ *
+ * Copyright 2020  GNOME Foundation
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "gtknotebookaccessible.h"
+
+G_BEGIN_DECLS
+
+void    gtk_notebook_accessible_update_page     (GtkNotebookAccessible *self,
+                                                 int                    page_num);
+
+G_END_DECLS

gtk/gtknotebook.c

@@ -55,7 +55,7 @@
 #include "gtkwidgetpaintable.h"
 #include "gtknative.h"
 
-#include "a11y/gtknotebookaccessible.h"
+#include "a11y/gtknotebookaccessibleprivate.h"
 
 #include <stdio.h>
 #include <string.h>
@@ -5298,6 +5298,7 @@ gtk_notebook_real_switch_page (GtkNotebook     *notebook,
 {
   GList *list = gtk_notebook_find_child (notebook, GTK_WIDGET (child));
   GtkNotebookPage *page = GTK_NOTEBOOK_PAGE_FROM_LIST (list);
+  AtkObject *accessible;
   gboolean child_has_focus;
 
   if (notebook->cur_page == page || !gtk_widget_get_visible (GTK_WIDGET (child)))
@@ -5343,6 +5344,11 @@ gtk_notebook_real_switch_page (GtkNotebook     *notebook,
 
   update_arrow_state (notebook);
 
+  accessible = _gtk_widget_peek_accessible (GTK_WIDGET (notebook));
+  if (accessible != NULL)
+    gtk_notebook_accessible_update_page (GTK_NOTEBOOK_ACCESSIBLE (accessible),
+                                         gtk_notebook_get_current_page (notebook));
+
   gtk_widget_queue_resize (GTK_WIDGET (notebook));
   gtk_widget_queue_resize (notebook->tabs_widget);
   g_object_notify_by_pspec (G_OBJECT (notebook), properties[PROP_PAGE]);
@@ -5904,8 +5910,6 @@ gtk_notebook_set_current_page (GtkNotebook *notebook,
   list = g_list_nth (notebook->children, page_num);
   if (list)
     gtk_notebook_switch_page (notebook, GTK_NOTEBOOK_PAGE_FROM_LIST (list));
-
-  g_object_notify_by_pspec (G_OBJECT (notebook), properties[PROP_PAGE]);
 }
 
 /**