qom: add object_property_add_alias()
Sometimes an object needs to present a property which is actually on
another object, or it needs to provide an alias name for an existing
property.
Examples:
a.foo -> b.foo
a.old_name -> a.new_name
The new object_property_add_alias() API allows objects to alias a
property on the same object or another object. The source and target
names can be different.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
diff --git a/qom/object.c b/qom/object.c
index 3876618..a760514 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1550,6 +1550,57 @@
NULL, NULL, (void *)v, errp);
}
+typedef struct {
+ Object *target_obj;
+ const char *target_name;
+} AliasProperty;
+
+static void property_get_alias(Object *obj, struct Visitor *v, void *opaque,
+ const char *name, Error **errp)
+{
+ AliasProperty *prop = opaque;
+
+ object_property_get(prop->target_obj, v, prop->target_name, errp);
+}
+
+static void property_set_alias(Object *obj, struct Visitor *v, void *opaque,
+ const char *name, Error **errp)
+{
+ AliasProperty *prop = opaque;
+
+ object_property_set(prop->target_obj, v, prop->target_name, errp);
+}
+
+static void property_release_alias(Object *obj, const char *name, void *opaque)
+{
+ AliasProperty *prop = opaque;
+
+ g_free(prop);
+}
+
+void object_property_add_alias(Object *obj, const char *name,
+ Object *target_obj, const char *target_name,
+ Error **errp)
+{
+ AliasProperty *prop;
+ ObjectProperty *target_prop;
+
+ target_prop = object_property_find(target_obj, target_name, errp);
+ if (!target_prop) {
+ return;
+ }
+
+ prop = g_malloc(sizeof(*prop));
+ prop->target_obj = target_obj;
+ prop->target_name = target_name;
+
+ object_property_add(obj, name, target_prop->type,
+ property_get_alias,
+ property_set_alias,
+ property_release_alias,
+ prop, errp);
+}
+
static void object_instance_init(Object *obj)
{
object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
