qom: Change object property iterator API contract

Currently the ObjectProperty iterator API works as follows:

  ObjectPropertyIterator *iter;

  iter = object_property_iter_init(obj);
  while ((prop = object_property_iter_next(iter))) {
     ...
  }
  object_property_iter_free(iter);

This has the benefit that the ObjectPropertyIterator struct
can be opaque, but has the downside that callers need to
explicitly call a free function. It is also not in keeping
with iterator style used elsewhere in QEMU/GLib2.

This patch changes the API to use stack allocation instead:

  ObjectPropertyIterator iter;

  object_property_iter_init(&iter, obj);
  while ((prop = object_property_iter_next(&iter))) {
     ...
  }

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[AF: Fused ObjectPropertyIterator struct with typedef]
Signed-off-by: Andreas Färber <afaerber@suse.de>

1 files changed, 3 insertions, 4 deletions

diff --git a/vl.c b/vl.c
index b7a083eb56..f043009f67 100644
--- a/vl.c
+++ b/vl.c
@@ -1535,14 +1535,14 @@ MachineInfoList *qmp_query_machines(Error **errp)
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
 {
     ObjectProperty *prop;
-    ObjectPropertyIterator *iter;
+    ObjectPropertyIterator iter;
 
     if (!qemu_opt_has_help_opt(opts)) {
         return 0;
     }
 
-    iter = object_property_iter_init(OBJECT(machine));
-    while ((prop = object_property_iter_next(iter))) {
+    object_property_iter_init(&iter, OBJECT(machine));
+    while ((prop = object_property_iter_next(&iter))) {
         if (!prop->set) {
             continue;
         }
@@ -1555,7 +1555,6 @@ static int machine_help_func(QemuOpts *opts, MachineState *machine)
             error_printf("\n");
         }
     }
-    object_property_iter_free(iter);
 
     return 1;
 }