qlist: add qlist_size()

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/qlist.c b/qlist.c
index 88498b1..b48ec5b 100644
--- a/qlist.c
+++ b/qlist.c
@@ -124,6 +124,19 @@
     return QTAILQ_EMPTY(&qlist->head);
 }
 
+static void qlist_size_iter(QObject *obj, void *opaque)
+{
+    size_t *count = opaque;
+    (*count)++;
+}
+
+size_t qlist_size(const QList *qlist)
+{
+    size_t count = 0;
+    qlist_iter(qlist, qlist_size_iter, &count);
+    return count;
+}
+
 /**
  * qobject_to_qlist(): Convert a QObject into a QList
  */