[gtk/a11y/atspi: 38/43] atspicontext: Implement GetIndexInParent

[Emmanuele Bassi <ebassi src gnome org>]

commit 023366bb60abe8a14af02a3b940d838b1880ad38
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Oct 9 20:24:52 2020 -0400

    atspicontext: Implement GetIndexInParent
    
    This is needed for ATs to take our tree seriously.

 gtk/a11y/gtkatspicontext.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
---
diff --git a/gtk/a11y/gtkatspicontext.c b/gtk/a11y/gtkatspicontext.c
index 4ed4f97f18..4d24f1a959 100644
--- a/gtk/a11y/gtkatspicontext.c
+++ b/gtk/a11y/gtkatspicontext.c
@@ -200,6 +200,30 @@ handle_accessible_method (GDBusConnection       *connection,
 
       g_dbus_method_invocation_return_value (invocation, g_variant_new ("(a(so))", &builder));
     }
+  else if (g_strcmp0 (method_name, "GetIndexInParent") == 0)
+    {
+      GtkAccessible *accessible = gtk_at_context_get_accessible (GTK_AT_CONTEXT (self));
+      GtkWidget *widget = GTK_WIDGET (accessible);
+      GtkWidget *parent = gtk_widget_get_parent (widget);
+      GtkWidget *child;
+      int idx;
+
+      idx = 0;
+      for (child = gtk_widget_get_first_child (parent);
+           child;
+           child = gtk_widget_get_next_sibling (child))
+        {
+          if (!gtk_widget_get_visible (child))
+            continue;
+
+          if (child == widget)
+            break;
+
+          idx++;
+        }
+
+      g_dbus_method_invocation_return_value (invocation, g_variant_new ("(i)", idx));
+    }
 }
 
 static GVariant *