[Memory Leak] Partial fix for bug 129

#129

This commit attempts to partially fix bug 129.  It cannot be
completely fixed at the moment due to a bug in GUPnP.

https://bugzilla.gnome.org/show_bug.cgi?id=708751

At least we're freeing the list now, if not the strings that it
contains.  Also, to reduce the effect of the memory leak, this
commit ensures that it only happens once per renderer rather than
once each time we receive an event from a renderer.  The assumption
is that a device will not dynamically change the DLNA classes that
it supports.

Signed-off-by: Mark Ryan <mark.d.ryan@intel.com>

libdleyna/renderer/device.c

@@ -1118,16 +1118,36 @@ static GVariant *prv_as_prop_from_list(GList *list)
 	return g_variant_ref_sink(g_variant_builder_end(&vb));
 }
 
-static void prv_update_prop_dlna_device_classes(GUPnPDeviceInfo *proxy,
-						GHashTable *props)
+static GVariant *prv_update_prop_dlna_device_classes(GUPnPDeviceInfo *proxy,
+						     GHashTable *props)
 {
-	GList *dlna_classes =
+	GVariant *retval;
+	GList *dlna_classes;
+
+	retval = g_hash_table_lookup(props,
+				     DLR_INTERFACE_PROP_DLNA_DEVICE_CLASSES);
+	if (retval)
+		goto on_exit;
+
+	dlna_classes =
 		gupnp_device_info_list_dlna_device_class_identifier(proxy);
 
-	if (dlna_classes != NULL)
-		g_hash_table_insert(props,
-				    DLR_INTERFACE_PROP_DLNA_DEVICE_CLASSES,
-				    prv_as_prop_from_list(dlna_classes));
+	if (!dlna_classes)
+		goto on_exit;
+
+	retval = prv_as_prop_from_list(dlna_classes);
+	g_hash_table_insert(props, DLR_INTERFACE_PROP_DLNA_DEVICE_CLASSES,
+			    retval);
+
+	/* TODO: We should actually be calling g_list_free_full here but the
+	   strings in dlna_classes are allocated by libxml and not glib.  So
+	   until this is fixed we're stuck with this.  */
+
+	g_list_free(dlna_classes);
+
+on_exit:
+
+	return retval;
 }
 
 static void prv_add_actions(dlr_device_t *device,
@@ -1165,10 +1185,8 @@ static void prv_add_actions(dlr_device_t *device,
 
 	info = (GUPnPDeviceInfo *)dlr_device_get_context(device)->device_proxy;
 
-	prv_update_prop_dlna_device_classes(info, device->props.device_props);
-
-	val = g_hash_table_lookup(device->props.device_props,
-				  DLR_INTERFACE_PROP_DLNA_DEVICE_CLASSES);
+	val = prv_update_prop_dlna_device_classes(info,
+						  device->props.device_props);
 
 	/* If this device is not dlna compatible, there is no need */
 	/* to check for “X_DLNA_SeekTime” */
@@ -2234,7 +2252,7 @@ static void prv_update_device_props(GUPnPDeviceInfo *proxy, GHashTable *props)
 	GVariant *val;
 	gchar *str;
 
-	prv_update_prop_dlna_device_classes(proxy, props);
+	(void) prv_update_prop_dlna_device_classes(proxy, props);
 
 	val = g_variant_ref_sink(g_variant_new_string(
 				gupnp_device_info_get_device_type(proxy)));