qobject: Change qobject_to_json()'s value to GString

qobject_to_json() and qobject_to_json_pretty() build a GString, then
covert it to QString.  Just one of the callers actually needs a
QString: qemu_rbd_parse_filename().  A few others need a string they
can modify: qmp_send_response(), qga's send_response(), to_json_str(),
and qmp_fd_vsend_fds().  The remainder just need a string.

Change qobject_to_json() and qobject_to_json_pretty() to return the
GString.

qemu_rbd_parse_filename() now has to convert to QString.  All others
save a QString temporary.  to_json_str() actually becomes a bit
simpler, because GString provides more convenient modification
functions.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201211171152.146877-6-armbru@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/tests/test-visitor-serialization.c b/tests/test-visitor-serialization.c
index dfe120a..4629958 100644
--- a/tests/test-visitor-serialization.c
+++ b/tests/test-visitor-serialization.c
@@ -957,15 +957,15 @@ static void qmp_deserialize(void **native_out, void *datap,
                             VisitorFunc visit, Error **errp)
 {
     QmpSerializeData *d = datap;
-    QString *output_json;
+    GString *output_json;
     QObject *obj_orig, *obj;
 
     visit_complete(d->qov, &d->obj);
     obj_orig = d->obj;
     output_json = qobject_to_json(obj_orig);
-    obj = qobject_from_json(qstring_get_str(output_json), &error_abort);
+    obj = qobject_from_json(output_json->str, &error_abort);
 
-    qobject_unref(output_json);
+    g_string_free(output_json, true);
     d->qiv = qobject_input_visitor_new(obj);
     qobject_unref(obj_orig);
     qobject_unref(obj);