qapi: Use QNull for a more regular visit_type_null()

Make visit_type_null() take an @obj argument like its buddies.  This
helps keep the next commit simple.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>

3 files changed, 18 insertions, 7 deletions

diff --git a/tests/check-qnull.c b/tests/check-qnull.c
index 1ab7c983a5..5c6eb0adc8 100644
--- a/tests/check-qnull.c
+++ b/tests/check-qnull.c
@@ -38,6 +38,7 @@ static void qnull_visit_test(void)
 {
     QObject *obj;
     Visitor *v;
+    QNull *null;
 
     /*
      * Most tests of interactions between QObject and visitors are in
@@ -49,13 +50,17 @@ static void qnull_visit_test(void)
     obj = QOBJECT(qnull());
     v = qobject_input_visitor_new(obj);
     qobject_decref(obj);
-    visit_type_null(v, NULL, &error_abort);
+    visit_type_null(v, NULL, &null, &error_abort);
+    g_assert(obj == QOBJECT(&qnull_));
+    QDECREF(null);
     visit_free(v);
 
+    null = NULL;
     v = qobject_output_visitor_new(&obj);
-    visit_type_null(v, NULL, &error_abort);
+    visit_type_null(v, NULL, &null, &error_abort);
     visit_complete(v, &obj);
     g_assert(obj == QOBJECT(&qnull_));
+    QDECREF(null);
     qobject_decref(obj);
     visit_free(v);
 
diff --git a/tests/test-qobject-input-visitor.c b/tests/test-qobject-input-visitor.c
index 34bab8a913..f98caf9818 100644
--- a/tests/test-qobject-input-visitor.c
+++ b/tests/test-qobject-input-visitor.c
@@ -510,6 +510,7 @@ static void test_visitor_in_null(TestInputVisitorData *data,
 {
     Visitor *v;
     Error *err = NULL;
+    QNull *null;
     char *tmp;
 
     /*
@@ -524,12 +525,15 @@ static void test_visitor_in_null(TestInputVisitorData *data,
     v = visitor_input_test_init_full(data, false,
                                      "{ 'a': null, 'b': '' }");
     visit_start_struct(v, NULL, NULL, 0, &error_abort);
-    visit_type_null(v, "a", &error_abort);
-    visit_type_null(v, "b", &err);
+    visit_type_null(v, "a", &null, &error_abort);
+    g_assert(qobject_type(QOBJECT(null)) == QTYPE_QNULL);
+    QDECREF(null);
+    visit_type_null(v, "b", &null, &err);
     error_free_or_abort(&err);
+    g_assert(!null);
     visit_type_str(v, "c", &tmp, &err);
-    g_assert(!tmp);
     error_free_or_abort(&err);
+    g_assert(!tmp);
     visit_check_struct(v, &error_abort);
     visit_end_struct(v, NULL);
 }
@@ -1087,6 +1091,7 @@ static void test_visitor_in_fail_struct_missing(TestInputVisitorData *data,
     Error *err = NULL;
     Visitor *v;
     QObject *any;
+    QNull *null;
     GenericAlternate *alt;
     bool present;
     int en;
@@ -1120,7 +1125,7 @@ static void test_visitor_in_fail_struct_missing(TestInputVisitorData *data,
     error_free_or_abort(&err);
     visit_type_any(v, "any", &any, &err);
     error_free_or_abort(&err);
-    visit_type_null(v, "null", &err);
+    visit_type_null(v, "null", &null, &err);
     error_free_or_abort(&err);
     visit_start_list(v, "sub", NULL, 0, &error_abort);
     visit_start_struct(v, NULL, NULL, 0, &error_abort);
diff --git a/tests/test-qobject-output-visitor.c b/tests/test-qobject-output-visitor.c
index 749c54065f..8f1fcd49cb 100644
--- a/tests/test-qobject-output-visitor.c
+++ b/tests/test-qobject-output-visitor.c
@@ -445,11 +445,12 @@ static void test_visitor_out_alternate(TestOutputVisitorData *data,
 static void test_visitor_out_null(TestOutputVisitorData *data,
                                   const void *unused)
 {
+    QNull *null = NULL;
     QDict *qdict;
     QObject *nil;
 
     visit_start_struct(data->ov, NULL, NULL, 0, &error_abort);
-    visit_type_null(data->ov, "a", &error_abort);
+    visit_type_null(data->ov, "a", &null, &error_abort);
     visit_check_struct(data->ov, &error_abort);
     visit_end_struct(data->ov, NULL);
     qdict = qobject_to_qdict(visitor_get(data));