From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48108) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X1tXB-0002HM-If for qemu-devel@nongnu.org; Tue, 01 Jul 2014 04:35:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X1tX5-0000ol-JM for qemu-devel@nongnu.org; Tue, 01 Jul 2014 04:35:25 -0400 Received: from mail-wi0-x236.google.com ([2a00:1450:400c:c05::236]:48255) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X1tX5-0000od-8R for qemu-devel@nongnu.org; Tue, 01 Jul 2014 04:35:19 -0400 Received: by mail-wi0-f182.google.com with SMTP id bs8so7248134wib.9 for ; Tue, 01 Jul 2014 01:35:18 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Tue, 1 Jul 2014 10:34:51 +0200 Message-Id: <1404203705-15674-2-git-send-email-pbonzini@redhat.com> In-Reply-To: <1404203705-15674-1-git-send-email-pbonzini@redhat.com> References: <1404203705-15674-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PULL 01/15] qom: add object_property_add_alias() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi From: Stefan Hajnoczi 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 Reviewed-by: Peter Crosthwaite --- include/qom/object.h | 20 ++++++++++++++++++++ qom/object.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 71 insertions(+) diff --git a/include/qom/object.h b/include/qom/object.h index b882ccc..44c513f 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -1231,6 +1231,26 @@ void object_property_add_uint64_ptr(Object *obj, const char *name, const uint64_t *v, Error **Errp); /** + * object_property_add_alias: + * @obj: the object to add a property to + * @name: the name of the property + * @target_obj: the object to forward property access to + * @target_name: the name of the property on the forwarded object + * @errp: if an error occurs, a pointer to an area to store the error + * + * Add an alias for a property on an object. This function will add a property + * of the same type as the forwarded property. + * + * The caller must ensure that @target_obj stays alive as long as + * this property exists. In the case of a child object or an alias on the same + * object this will be the case. For aliases to other objects the caller is + * responsible for taking a reference. + */ +void object_property_add_alias(Object *obj, const char *name, + Object *target_obj, const char *target_name, + Error **errp); + +/** * object_child_foreach: * @obj: the object whose children will be navigated * @fn: the iterator function to be called 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 @@ void object_property_add_uint64_ptr(Object *obj, const char *name, 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); -- 1.8.3.1