[at-spi2-core] Only call an event listener once per event

[Mike Gorse <mgorse src gnome org>]

commit 0927d749d332c1719856545f53a00ea28a7d4e25
Author: Mike Gorse <mgorse suse com>
Date:   Fri Oct 26 16:01:35 2012 -0500

    Only call an event listener once per event
    
    If an event listener is registered for an event more than once (ie,
    registering both the event and its superset), then only notify it once.

 atspi/atspi-event-listener.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)
---
diff --git a/atspi/atspi-event-listener.c b/atspi/atspi-event-listener.c
index 26f1105..ba5d126 100644
--- a/atspi/atspi-event-listener.c
+++ b/atspi/atspi-event-listener.c
@@ -788,6 +788,7 @@ _atspi_send_event (AtspiEvent *e)
 {
   char *category, *name, *detail;
   GList *l;
+  GList *called_listeners = NULL;
 
   /* Ensure that the value is set to avoid a Python exception */
   /* TODO: Figure out how to do this without using a private field */
@@ -809,12 +810,24 @@ _atspi_send_event (AtspiEvent *e)
         (entry->name == NULL || !strcmp (name, entry->name)) &&
         detail_matches_listener (detail, entry->detail))
     {
+      GList *l2;
+      for (l2 = called_listeners; l2; l2 = l2->next)
+      {
+        EventListenerEntry *e2 = l2->data;
+        if (entry->callback == e2->callback && entry->user_data == e2->user_data)
+          break;
+      }
+      if (!l2)
+      {
         entry->callback (atspi_event_copy (e), entry->user_data);
+        called_listeners = g_list_prepend (called_listeners, entry);
+      }
     }
   }
   if (detail) g_free (detail);
   g_free (name);
   g_free (category);
+  g_list_free (called_listeners);
 }
 
 DBusHandlerResult