[gtk/a11y/atspi-child: 1/3] a11y: Add child state change to GtkATContext

[Emmanuele Bassi <ebassi src gnome org>]

commit fbb08a30e242fb6f10d5ed9094548bdc96cc494b
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Oct 15 14:49:14 2020 +0100

    a11y: Add child state change to GtkATContext
    
    And the required private API in GtkAccessible to notify AT contexts of
    changes in the children list.

 gtk/gtkaccessible.c        | 24 ++++++++++++++++++++++++
 gtk/gtkaccessibleprivate.h |  4 ++++
 gtk/gtkatcontext.c         | 16 ++++++++++++++++
 gtk/gtkatcontextprivate.h  | 17 +++++++++++++++++
 4 files changed, 61 insertions(+)
---
diff --git a/gtk/gtkaccessible.c b/gtk/gtkaccessible.c
index bef2ced14e..32916de27b 100644
--- a/gtk/gtkaccessible.c
+++ b/gtk/gtkaccessible.c
@@ -751,3 +751,27 @@ gtk_accessible_should_present (GtkAccessible *self)
 
   return TRUE;
 }
+
+void
+gtk_accessible_update_children (GtkAccessible           *self,
+                                GtkAccessible           *child,
+                                GtkAccessibleChildState  state)
+{
+  GtkATContext *context;
+
+  if (GTK_IS_WIDGET (self) &&
+      gtk_widget_get_root (GTK_WIDGET (self)) == NULL)
+    return;
+
+  context = gtk_accessible_get_at_context (self);
+
+  /* propagate changes up from ignored widgets */
+  if (gtk_accessible_get_accessible_role (self) == GTK_ACCESSIBLE_ROLE_NONE)
+    context = gtk_accessible_get_at_context (GTK_ACCESSIBLE (gtk_widget_get_parent (GTK_WIDGET (self))));
+
+  if (context == NULL)
+    return;
+
+  gtk_at_context_child_changed (context, state, child);
+  gtk_at_context_update (context);
+}
diff --git a/gtk/gtkaccessibleprivate.h b/gtk/gtkaccessibleprivate.h
index 966efc3abb..873af7009a 100644
--- a/gtk/gtkaccessibleprivate.h
+++ b/gtk/gtkaccessibleprivate.h
@@ -49,4 +49,8 @@ gboolean        gtk_accessible_get_platform_state (GtkAccessible              *s
 
 void            gtk_accessible_bounds_changed   (GtkAccessible *self);
 
+void            gtk_accessible_update_children  (GtkAccessible           *self,
+                                                 GtkAccessible           *child,
+                                                 GtkAccessibleChildState  state);
+
 G_END_DECLS
diff --git a/gtk/gtkatcontext.c b/gtk/gtkatcontext.c
index dd771bc10c..6e0c54693f 100644
--- a/gtk/gtkatcontext.c
+++ b/gtk/gtkatcontext.c
@@ -155,6 +155,13 @@ gtk_at_context_real_bounds_change (GtkATContext *self)
 {
 }
 
+static void
+gtk_at_context_real_child_change (GtkATContext             *self,
+                                  GtkAccessibleChildChange  change,
+                                  GtkAccessible            *child)
+{
+}
+
 static void
 gtk_at_context_class_init (GtkATContextClass *klass)
 {
@@ -167,6 +174,7 @@ gtk_at_context_class_init (GtkATContextClass *klass)
   klass->state_change = gtk_at_context_real_state_change;
   klass->platform_change = gtk_at_context_real_platform_change;
   klass->bounds_change = gtk_at_context_real_bounds_change;
+  klass->child_change = gtk_at_context_real_child_change;
 
   /**
    * GtkATContext:accessible-role:
@@ -979,3 +987,11 @@ gtk_at_context_bounds_changed (GtkATContext *self)
 {
   GTK_AT_CONTEXT_GET_CLASS (self)->bounds_change (self);
 }
+
+void
+gtk_at_context_child_changed (GtkATContext             *self,
+                              GtkAccessibleChildChange  change,
+                              GtkAccessible            *child)
+{
+  GTK_AT_CONTEXT_GET_CLASS (self)->child_change (self, change, child);
+}
diff --git a/gtk/gtkatcontextprivate.h b/gtk/gtkatcontextprivate.h
index edc7fa3c94..85d897be90 100644
--- a/gtk/gtkatcontextprivate.h
+++ b/gtk/gtkatcontextprivate.h
@@ -90,6 +90,16 @@ typedef enum {
   GTK_ACCESSIBLE_PLATFORM_CHANGE_FOCUSED   = 1 << GTK_ACCESSIBLE_PLATFORM_STATE_FOCUSED,
 } GtkAccessiblePlatformChange;
 
+typedef enum {
+  GTK_ACCESSIBLE_CHILD_STATE_ADDED,
+  GTK_ACCESSIBLE_CHILD_STATE_REMOVED
+} GtkAccessibleChildState;
+
+typedef enum {
+  GTK_ACCESSIBLE_CHILD_CHANGE_ADDED   = 1 << GTK_ACCESSIBLE_CHILD_STATE_ADDED,
+  GTK_ACCESSIBLE_CHILD_CHANGE_REMOVED = 1 << GTK_ACCESSIBLE_CHILD_STATE_REMOVED
+} GtkAccessibleChildChange;
+
 struct _GtkATContext
 {
   GObject parent_instance;
@@ -124,6 +134,10 @@ struct _GtkATContextClass
                             GtkAccessiblePlatformChange  changed_platform);
 
   void (* bounds_change) (GtkATContext                *self);
+
+  void (* child_change) (GtkATContext             *self,
+                         GtkAccessibleChildChange  changed_child,
+                         GtkAccessible            *child);
 };
 
 GdkDisplay *            gtk_at_context_get_display              (GtkATContext          *self);
@@ -158,6 +172,9 @@ char *                  gtk_at_context_get_description          (GtkATContext
 void                    gtk_at_context_platform_changed         (GtkATContext                *self,
                                                                  GtkAccessiblePlatformChange  change);
 void                    gtk_at_context_bounds_changed           (GtkATContext                *self);
+void                    gtk_at_context_child_changed            (GtkATContext                *self,
+                                                                 GtkAccessibleChildChange     change,
+                                                                 GtkAccessible               *child);
 
 const char *    gtk_accessible_property_get_attribute_name      (GtkAccessibleProperty property);
 const char *    gtk_accessible_relation_get_attribute_name      (GtkAccessibleRelation relation);