Merge branch 'fix_custom_accessible_hierarchy' into 'main'

Allow setting accessible parent and next sibling

See merge request GNOME/gtk!5517

gtk/gtkaccessible.c

@@ -45,6 +45,11 @@
  * [vfunc@Gtk.Accessible.get_next_accessible_sibling] virtual functions.
  * Note that you can not create a top-level accessible object as of now,
  * which means that you must always have a parent accessible object.
+ * Also note that when an accessible object does not correspond to a widget,
+ * and it has children, whose implementation you don't control,
+ * it is necessary to ensure the correct shape of the a11y tree
+ * by calling [method@Gtk.Accessible.set_accessible_parent] and
+ * updating the sibling by [method@Gtk.Accessible.update_next_accessible_sibling].
  */
 
 #include "config.h"
@@ -117,7 +122,85 @@ gtk_accessible_get_accessible_parent (GtkAccessible *self)
 {
   g_return_val_if_fail (GTK_IS_ACCESSIBLE (self), NULL);
 
-  return GTK_ACCESSIBLE_GET_IFACE (self)->get_accessible_parent (self);
+  GtkATContext *context;
+  GtkAccessible *parent = NULL;
+
+  context = gtk_accessible_get_at_context (self);
+  if (context != NULL)
+    parent = gtk_at_context_get_accessible_parent (context);
+ 
+  if (parent != NULL)
+    return parent;
+  else
+    return GTK_ACCESSIBLE_GET_IFACE (self)->get_accessible_parent (self);
+}
+
+/**
+ * gtk_accessible_set_accessible_parent:
+ * @self: an accessible object
+ * @parent: (nullable): the parent accessible object
+ * @next_sibling: (nullable): the sibling accessible object
+ *
+ * Sets the parent and sibling of an accessible object.
+ *
+ * This function is meant to be used by accessible implementations that are
+ * not part of the widget hierarchy, and but act as a logical bridge between
+ * widgets. For instance, if a widget creates an object that holds metadata
+ * for each child, and you want that object to implement the `GtkAccessible`
+ * interface, you will use this function to ensure that the parent of each
+ * child widget is the metadata object, and the parent of each metadata
+ * object is the container widget.
+ *
+ * Since: 4.10
+ */
+void
+gtk_accessible_set_accessible_parent (GtkAccessible *self,
+                                      GtkAccessible *parent,
+                                      GtkAccessible *next_sibling)
+{
+  g_return_if_fail (GTK_IS_ACCESSIBLE (self));
+  g_return_if_fail (parent == NULL || GTK_IS_ACCESSIBLE (parent));
+  g_return_if_fail (next_sibling == NULL || GTK_IS_ACCESSIBLE (parent));
+  GtkATContext *context;
+
+  context = gtk_accessible_get_at_context (self);
+  if (context != NULL)
+    {
+      gtk_at_context_set_accessible_parent (context, parent);
+      gtk_at_context_set_next_accessible_sibling (context, next_sibling);
+    }
+}
+
+/**
+ * gtk_accessible_update_next_accessible_sibling:
+ * @self: a `GtkAccessible`
+ * @new_sibling: (nullable): the new next accessible sibling to set
+ *
+ * Updates the next accessible sibling of @self.
+ * That might be useful when a new child of a custom `GtkAccessible`
+ * is created, and it needs to be linked to a previous child.
+ *
+ * Since: 4.10
+ */
+void
+gtk_accessible_update_next_accessible_sibling (GtkAccessible *self,
+                                               GtkAccessible *new_sibling)
+{
+  GtkATContext *context;
+
+  g_return_if_fail (GTK_IS_ACCESSIBLE (self));
+
+  context = gtk_accessible_get_at_context (self);
+  if (!context)
+    return;
+  
+  if (gtk_at_context_get_accessible_parent (context) == NULL)
+  {
+    g_critical ("Failed to update next accessible sibling: no parent accessible set for this accessible");
+    return;
+  }
+
+  gtk_at_context_set_next_accessible_sibling (context, new_sibling);
 }
 
 /**
@@ -153,7 +236,13 @@ gtk_accessible_get_next_accessible_sibling (GtkAccessible *self)
 {
   g_return_val_if_fail (GTK_IS_ACCESSIBLE (self), NULL);
 
-  return GTK_ACCESSIBLE_GET_IFACE (self)->get_next_accessible_sibling (self);
+  GtkATContext *context;
+
+  context = gtk_accessible_get_at_context (self);
+  if (context != NULL && gtk_at_context_get_accessible_parent (context) != NULL)
+    return gtk_at_context_get_next_accessible_sibling (context);
+  else
+    return GTK_ACCESSIBLE_GET_IFACE (self)->get_next_accessible_sibling (self);
 }
 
 /**

gtk/gtkaccessible.h

@@ -164,11 +164,20 @@ gboolean gtk_accessible_get_platform_state (GtkAccessible              *self,
 GDK_AVAILABLE_IN_4_10
 GtkAccessible * gtk_accessible_get_accessible_parent (GtkAccessible *self);
 
+GDK_AVAILABLE_IN_4_10
+void gtk_accessible_set_accessible_parent (GtkAccessible *self,
+                                           GtkAccessible *parent,
+                                           GtkAccessible *next_sibling);
+
 GDK_AVAILABLE_IN_4_10
 GtkAccessible * gtk_accessible_get_first_accessible_child (GtkAccessible *self);
 
 GDK_AVAILABLE_IN_4_10
 GtkAccessible * gtk_accessible_get_next_accessible_sibling (GtkAccessible *self);
+GDK_AVAILABLE_IN_4_10
+void gtk_accessible_update_next_accessible_sibling (GtkAccessible *self,
+                                                    GtkAccessible *new_sibling);
+
 
 GDK_AVAILABLE_IN_4_10
 gboolean gtk_accessible_get_bounds (GtkAccessible *self,

gtk/gtkatcontext.c

@@ -447,6 +447,70 @@ gtk_at_context_get_accessible_role (GtkATContext *self)
   return self->accessible_role;
 }
 
+/*< private >
+ * gtk_at_context_get_accessible_parent:
+ * @self: a `GtkAtContext`
+ *
+ * Retrieves the parent accessible object of the given `GtkAtContext`.
+ *
+ * Returns: (nullable) (transfer none): the parent accessible object, or `NULL` if not set.
+ */
+GtkAccessible *
+gtk_at_context_get_accessible_parent (GtkATContext *self)
+{
+  g_return_val_if_fail (GTK_IS_AT_CONTEXT (self), NULL);
+  
+  return self->accessible_parent;
+}
+
+/*< private >
+ * gtk_at_context_set_accessible_parent:
+ * @self: a `GtkAtContext`
+ * @parent: the parent `GtkAccessible` to set
+ *
+ * Sets the parent accessible object of the given `GtkAtContext`.
+ */
+void
+gtk_at_context_set_accessible_parent (GtkATContext *self,
+                                      GtkAccessible *parent)
+{
+  g_return_if_fail (GTK_IS_AT_CONTEXT (self));
+  
+  g_set_object (&self->accessible_parent, parent);
+}
+
+/*< private >
+ * gtk_at_context_get_next_accessible_sibling:
+ * @self: a `GtkAtContext`
+ *
+ * Retrieves the next accessible sibling of the given `GtkAtContext`.
+ *
+ * Returns: (nullable) (transfer none): the next accessible sibling.
+ */
+GtkAccessible *
+gtk_at_context_get_next_accessible_sibling (GtkATContext *self)
+{
+  g_return_val_if_fail (GTK_IS_AT_CONTEXT (self), NULL);
+  
+  return self->next_accessible_sibling;
+}
+
+/*< private >
+ * gtk_at_context_set_next_accessible_sibling:
+ * @self: a `GtkAtContext`
+ * @sibling: (nullable): the next accessible sibling
+ *
+ * Sets the next accessible sibling object of the given `GtkAtContext`.
+ */
+void
+gtk_at_context_set_next_accessible_sibling (GtkATContext *self,
+                                            GtkAccessible *sibling)
+{
+  g_return_if_fail (GTK_IS_AT_CONTEXT (self));
+  
+  g_set_object (&self->next_accessible_sibling, sibling);
+}
+
 /*< private >
  * gtk_at_context_set_display:
  * @self: a `GtkATContext`

gtk/gtkatcontextprivate.h

@@ -87,6 +87,8 @@ struct _GtkATContext
 
   GtkAccessibleRole accessible_role;
   GtkAccessible *accessible;
+  GtkAccessible *accessible_parent;
+  GtkAccessible *next_accessible_sibling;
   GdkDisplay *display;
 
   GtkAccessibleAttributeSet *states;
@@ -179,4 +181,15 @@ const char *    gtk_accessible_property_get_attribute_name      (GtkAccessiblePr
 const char *    gtk_accessible_relation_get_attribute_name      (GtkAccessibleRelation relation);
 const char *    gtk_accessible_state_get_attribute_name         (GtkAccessibleState    state);
 
+GtkAccessible *
+gtk_at_context_get_accessible_parent (GtkATContext *self);
+void
+gtk_at_context_set_accessible_parent (GtkATContext *self,
+                                      GtkAccessible *parent);
+GtkAccessible *
+gtk_at_context_get_next_accessible_sibling (GtkATContext *self);
+void
+gtk_at_context_set_next_accessible_sibling (GtkATContext *self,
+                                            GtkAccessible *sibling);
+
 G_END_DECLS

gtk/gtkstack.c

@@ -410,6 +410,9 @@ gtk_stack_page_set_property (GObject      *object,
     {
     case CHILD_PROP_CHILD:
       g_set_object (&info->widget, g_value_get_object (value));
+      gtk_accessible_set_accessible_parent (GTK_ACCESSIBLE (info->widget),
+                                            GTK_ACCESSIBLE (info),
+                                            NULL);
       break;
 
     case CHILD_PROP_NAME: