1 files changed, 29 insertions, 34 deletions

diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
index d44c676317..4d3cf78333 100644
--- a/qapi/qmp-output-visitor.c
+++ b/qapi/qmp-output-visitor.c
@@ -22,7 +22,6 @@
 typedef struct QStackEntry
 {
     QObject *value;
-    bool is_list_head;
     QTAILQ_ENTRY(QStackEntry) node;
 } QStackEntry;
 
@@ -52,9 +51,6 @@ static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value)
     assert(qov->root);
     assert(value);
     e->value = value;
-    if (qobject_type(e->value) == QTYPE_QLIST) {
-        e->is_list_head = true;
-    }
     QTAILQ_INSERT_HEAD(&qov->stack, e, node);
 }
 
@@ -82,9 +78,8 @@ static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
     QObject *cur = e ? e->value : NULL;
 
     if (!cur) {
-        /* FIXME we should require the user to reset the visitor, rather
-         * than throwing away the previous root */
-        qobject_decref(qov->root);
+        /* Don't allow reuse of visitor on more than one root */
+        assert(!qov->root);
         qov->root = value;
     } else {
         switch (qobject_type(cur)) {
@@ -93,6 +88,7 @@ static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
             qdict_put_obj(qobject_to_qdict(cur), name, value);
             break;
         case QTYPE_QLIST:
+            assert(!name);
             qlist_append_obj(qobject_to_qlist(cur), value);
             break;
         default:
@@ -111,13 +107,16 @@ static void qmp_output_start_struct(Visitor *v, const char *name, void **obj,
     qmp_output_push(qov, dict);
 }
 
-static void qmp_output_end_struct(Visitor *v, Error **errp)
+static void qmp_output_end_struct(Visitor *v)
 {
     QmpOutputVisitor *qov = to_qov(v);
-    qmp_output_pop(qov);
+    QObject *value = qmp_output_pop(qov);
+    assert(qobject_type(value) == QTYPE_QDICT);
 }
 
-static void qmp_output_start_list(Visitor *v, const char *name, Error **errp)
+static void qmp_output_start_list(Visitor *v, const char *name,
+                                  GenericList **listp, size_t size,
+                                  Error **errp)
 {
     QmpOutputVisitor *qov = to_qov(v);
     QList *list = qlist_new();
@@ -126,26 +125,17 @@ static void qmp_output_start_list(Visitor *v, const char *name, Error **errp)
     qmp_output_push(qov, list);
 }
 
-static GenericList *qmp_output_next_list(Visitor *v, GenericList **listp,
+static GenericList *qmp_output_next_list(Visitor *v, GenericList *tail,
                                          size_t size)
 {
-    GenericList *list = *listp;
-    QmpOutputVisitor *qov = to_qov(v);
-    QStackEntry *e = QTAILQ_FIRST(&qov->stack);
-
-    assert(e);
-    if (e->is_list_head) {
-        e->is_list_head = false;
-        return list;
-    }
-
-    return list ? list->next : NULL;
+    return tail->next;
 }
 
 static void qmp_output_end_list(Visitor *v)
 {
     QmpOutputVisitor *qov = to_qov(v);
-    qmp_output_pop(qov);
+    QObject *value = qmp_output_pop(qov);
+    assert(qobject_type(value) == QTYPE_QLIST);
 }
 
 static void qmp_output_type_int64(Visitor *v, const char *name, int64_t *obj,
@@ -196,18 +186,22 @@ static void qmp_output_type_any(Visitor *v, const char *name, QObject **obj,
     qmp_output_add_obj(qov, name, *obj);
 }
 
-/* Finish building, and return the root object. Will not be NULL. */
+static void qmp_output_type_null(Visitor *v, const char *name, Error **errp)
+{
+    QmpOutputVisitor *qov = to_qov(v);
+    qmp_output_add_obj(qov, name, qnull());
+}
+
+/* Finish building, and return the root object.
+ * The root object is never null. The caller becomes the object's
+ * owner, and should use qobject_decref() when done with it.  */
 QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
 {
-    /* FIXME: we should require that a visit occurred, and that it is
-     * complete (no starts without a matching end) */
-    QObject *obj = qov->root;
-    if (obj) {
-        qobject_incref(obj);
-    } else {
-        obj = qnull();
-    }
-    return obj;
+    /* A visit must have occurred, with each start paired with end.  */
+    assert(qov->root && QTAILQ_EMPTY(&qov->stack));
+
+    qobject_incref(qov->root);
+    return qov->root;
 }
 
 Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
@@ -234,18 +228,19 @@ QmpOutputVisitor *qmp_output_visitor_new(void)
 
     v = g_malloc0(sizeof(*v));
 
+    v->visitor.type = VISITOR_OUTPUT;
     v->visitor.start_struct = qmp_output_start_struct;
     v->visitor.end_struct = qmp_output_end_struct;
     v->visitor.start_list = qmp_output_start_list;
     v->visitor.next_list = qmp_output_next_list;
     v->visitor.end_list = qmp_output_end_list;
-    v->visitor.type_enum = output_type_enum;
     v->visitor.type_int64 = qmp_output_type_int64;
     v->visitor.type_uint64 = qmp_output_type_uint64;
     v->visitor.type_bool = qmp_output_type_bool;
     v->visitor.type_str = qmp_output_type_str;
     v->visitor.type_number = qmp_output_type_number;
     v->visitor.type_any = qmp_output_type_any;
+    v->visitor.type_null = qmp_output_type_null;
 
     QTAILQ_INIT(&v->stack);