[gtk/a11y/stackswitcher-tabs] notebook: Set accessible roles and properties

[Matthias Clasen <matthiasc src gnome org>]

commit fdca39205c7a8558245e468a9a8f2f1aea61540a
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Oct 14 19:06:46 2020 -0400

    notebook: Set accessible roles and properties
    
    Set up the necessary roles, relations and properties
    for the tab patterns. This parallels what we have done
    for GtkStackSwitcher, and implements the Tabs pattern
    as described in the ARIA authoring guidelines.

 gtk/gtknotebook.c | 42 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)
---
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index cdf873861f..116e7d54d9 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -1404,13 +1404,14 @@ gtk_notebook_init (GtkNotebook *notebook)
   gtk_widget_hide (notebook->header_widget);
   gtk_widget_set_parent (notebook->header_widget, GTK_WIDGET (notebook));
 
-  notebook->tabs_widget = gtk_gizmo_new ("tabs",
-                                         gtk_notebook_measure_tabs,
-                                         gtk_notebook_allocate_tabs,
-                                         gtk_notebook_snapshot_tabs,
-                                         NULL,
-                                         (GtkGizmoFocusFunc)gtk_widget_focus_self,
-                                         (GtkGizmoGrabFocusFunc)gtk_widget_grab_focus_self);
+  notebook->tabs_widget = gtk_gizmo_new_with_role ("tabs",
+                                                   GTK_ACCESSIBLE_ROLE_TAB_LIST,
+                                                   gtk_notebook_measure_tabs,
+                                                   gtk_notebook_allocate_tabs,
+                                                   gtk_notebook_snapshot_tabs,
+                                                   NULL,
+                                                   (GtkGizmoFocusFunc)gtk_widget_focus_self,
+                                                   (GtkGizmoGrabFocusFunc)gtk_widget_grab_focus_self);
   gtk_widget_set_hexpand (notebook->tabs_widget, TRUE);
   gtk_box_append (GTK_BOX (notebook->header_widget), notebook->tabs_widget);
 
@@ -3915,6 +3916,7 @@ gtk_notebook_insert_notebook_page (GtkNotebook *notebook,
   GList *list;
   GtkWidget *sibling;
   GtkEventController *controller;
+  GtkStackPage *stack_page;
 
   nchildren = g_list_length (notebook->children);
   if ((position < 0) || (position > nchildren))
@@ -3929,7 +3931,14 @@ gtk_notebook_insert_notebook_page (GtkNotebook *notebook,
   else
   sibling = notebook->arrow_widget[ARROW_RIGHT_AFTER];
 
-  page->tab_widget = gtk_gizmo_new ("tab", measure_tab, allocate_tab, NULL, NULL, NULL, NULL);
+  page->tab_widget = gtk_gizmo_new_with_role ("tab",
+                                              GTK_ACCESSIBLE_ROLE_TAB,
+                                              measure_tab,
+                                              allocate_tab,
+                                              NULL,
+                                              NULL,
+                                              NULL,
+                                              NULL);
   g_object_set_data (G_OBJECT (page->tab_widget), "notebook", notebook);
   gtk_widget_insert_before (page->tab_widget, notebook->tabs_widget, sibling);
   controller = gtk_drop_controller_motion_new ();
@@ -3951,6 +3960,15 @@ gtk_notebook_insert_notebook_page (GtkNotebook *notebook,
       g_object_set_data (G_OBJECT (page->tab_label), "notebook", notebook);
     }
 
+  stack_page = gtk_stack_get_page (GTK_STACK (notebook->stack_widget), page->child);
+  gtk_accessible_update_relation (GTK_ACCESSIBLE (page->tab_widget),
+                                  GTK_ACCESSIBLE_RELATION_CONTROLS, g_list_append (NULL, stack_page),
+                                  -1);
+
+  gtk_accessible_update_state (GTK_ACCESSIBLE (page->tab_widget),
+                               GTK_ACCESSIBLE_STATE_SELECTED, FALSE,
+                               -1);
+
   gtk_notebook_update_labels (notebook);
 
   if (!notebook->first_tab)
@@ -5303,12 +5321,20 @@ gtk_notebook_real_switch_page (GtkNotebook     *notebook,
       if (focus)
         child_has_focus = gtk_widget_is_ancestor (focus, notebook->cur_page->child);
       gtk_widget_unset_state_flags (notebook->cur_page->tab_widget, GTK_STATE_FLAG_CHECKED);
+
+      gtk_accessible_update_state (GTK_ACCESSIBLE (notebook->cur_page->tab_widget),
+                                   GTK_ACCESSIBLE_STATE_SELECTED, FALSE,
+                                   -1);
     }
 
   notebook->cur_page = page;
   gtk_widget_set_state_flags (page->tab_widget, GTK_STATE_FLAG_CHECKED, FALSE);
   gtk_widget_set_visible (notebook->header_widget, notebook->show_tabs);
 
+  gtk_accessible_update_state (GTK_ACCESSIBLE (notebook->cur_page->tab_widget),
+                               GTK_ACCESSIBLE_STATE_SELECTED, TRUE,
+                               -1);
+
   if (!notebook->focus_tab ||
       notebook->focus_tab->data != (gpointer) notebook->cur_page)
     notebook->focus_tab =