From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37944) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WxCe9-0003gN-5D for qemu-devel@nongnu.org; Wed, 18 Jun 2014 05:59:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WxCe4-0003Kk-2t for qemu-devel@nongnu.org; Wed, 18 Jun 2014 05:59:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54833) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WxCe3-0003Kd-Re for qemu-devel@nongnu.org; Wed, 18 Jun 2014 05:59:08 -0400 From: Stefan Hajnoczi Date: Wed, 18 Jun 2014 17:58:28 +0800 Message-Id: <1403085516-10340-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1403085516-10340-1-git-send-email-stefanha@redhat.com> References: <1403085516-10340-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v4 1/9] qom: add object_property_add_alias() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: cornelia.huck@de.ibm.com, Paolo Bonzini , peter.crosthwaite@xilinx.com, Andreas Faerber , 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 --- v4: * Coding style: typedef struct { on a single line [Andreas] v2: * Explain refcount handling in doc comment [Paolo] * Fix "property" duplicate typo [Peter Crosthwaite] * Add "the same object or" to clarify commit description [Igor] --- 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 a641dcd..854a0d5 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -1203,6 +1203,26 @@ 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 e42b254..b83c3a7 100644 --- a/qom/object.c +++ b/qom/object.c @@ -1515,6 +1515,57 @@ 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); -- 1.9.3