+bool
+shash_add_once(struct shash *sh, const char *name, const void *data)
+{
+ if (!shash_find(sh, name)) {
+ shash_add(sh, name, data);
+ return true;
+ } else {
+ return false;
+ }
+}
+
+void
+shash_add_assert(struct shash *sh, const char *name, const void *data)
+{
+ bool added OVS_UNUSED = shash_add_once(sh, name, data);
+ assert(added);
+}
+