engine: filter change signals properly

Testing revealed that we were transmitting any change signal that came
in from the bus up to user code, even if the engine in question was not
interested in receiving the signal.

This is a problem in the case that two DConfClient objects exist for
different profiles.  In that case, we'd get crosstalk between the
subscriptions that each client had made and change notifications would
appear in both clients even if the change only affected one.

1 files changed, 23 insertions, 2 deletions

diff --git a/engine/dconf-engine.c b/engine/dconf-engine.c
index c3e5707..33ffd57 100644
--- a/engine/dconf-engine.c
+++ b/engine/dconf-engine.c
@@ -1181,6 +1181,25 @@ dconf_engine_change_sync (DConfEngine     *engine,
   return TRUE;
 }
 
+static gboolean
+dconf_engine_is_interested_in_signal (DConfEngine *engine,
+                                      GBusType     bus_type,
+                                      const gchar *sender,
+                                      const gchar *path)
+{
+  gint i;
+
+  for (i = 0; i < engine->n_sources; i++)
+    {
+      DConfEngineSource *source = engine->sources[i];
+
+      if (source->bus_type == bus_type && g_str_equal (source->object_path, path))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
 void
 dconf_engine_handle_dbus_signal (GBusType     type,
                                  const gchar *sender,
@@ -1215,7 +1234,8 @@ dconf_engine_handle_dbus_signal (GBusType     type,
            * Check last_handled to determine if we should ignore it.
            */
           if (!engine->last_handled || !g_str_equal (engine->last_handled, tag))
-            dconf_engine_change_notify (engine, prefix, changes, tag, FALSE, NULL, engine->user_data);
+            if (dconf_engine_is_interested_in_signal (engine, type, sender, path))
+              dconf_engine_change_notify (engine, prefix, changes, tag, FALSE, NULL, engine->user_data);
 
           engines = g_slist_delete_link (engines, engines);
 
@@ -1244,7 +1264,8 @@ dconf_engine_handle_dbus_signal (GBusType     type,
         {
           DConfEngine *engine = engines->data;
 
-          dconf_engine_change_notify (engine, path, empty_str_list, "", TRUE, NULL, engine->user_data);
+          if (dconf_engine_is_interested_in_signal (engine, type, sender, path))
+            dconf_engine_change_notify (engine, path, empty_str_list, "", TRUE, NULL, engine->user_data);
 
           engines = g_slist_delete_link (engines, engines);