iterator: only unset GValue if it was inited

And add some function guards. From GLib 2.48 on it is
allowed to pass an uninitialised GValue to g_value_unset().

https://bugzilla.gnome.org/show_bug.cgi?id=763762

diff --git a/gst/gstiterator.c b/gst/gstiterator.c
index 77f0c02c3a7008dd17588827c39c6a62e230ae15..b15b20271d21446346dfea5e755a92b3a9b70677 100644 (file)
--- a/gst/gstiterator.c
+++ b/gst/gstiterator.c
@@ -607,6 +607,8 @@ gst_iterator_fold (GstIterator * it, GstIteratorFoldFunction func,
   GValue item = { 0, };
   GstIteratorResult result;
 
+  g_return_val_if_fail (it != NULL, GST_ITERATOR_ERROR);
+
   while (1) {
     result = gst_iterator_next (it, &item);
     switch (result) {
@@ -625,7 +627,13 @@ gst_iterator_fold (GstIterator * it, GstIteratorFoldFunction func,
   }
 
 fold_done:
+
+#if GLIB_CHECK_VERSION (2, 48, 0)
   g_value_unset (&item);
+#else
+  if (item.g_type != 0)
+    g_value_unset (&item);
+#endif
 
   return result;
 }