From 64607d088132abdb25bf30d93e97d0c8df7b364c Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 5 Jun 2014 13:11:51 +0200 Subject: [PATCH] qom: add a generic mechanism to resolve paths It may be desirable to have custom link<> properties that do more than just store an object. Even the addition of a "check" function is not enough if setting the link has side effects or if a non-standard reference counting is preferrable. Avoid the assumption that the opaque field of a link<> is a LinkProperty struct, by adding a generic "resolve" callback to ObjectProperty. This fixes aliases of link properties. Signed-off-by: Paolo Bonzini --- include/qom/object.h | 34 +++++++++++++++--- qom/object.c | 82 ++++++++++++++++++++++++++++---------------- 2 files changed, 82 insertions(+), 34 deletions(-) diff --git a/include/qom/object.h b/include/qom/object.h index 44c513f985..8a05a81a99 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -303,6 +303,25 @@ typedef void (ObjectPropertyAccessor)(Object *obj, const char *name, Error **errp); +/** + * ObjectPropertyResolve: + * @obj: the object that owns the property + * @opaque: the opaque registered with the property + * @part: the name of the property + * + * Resolves the #Object corresponding to property @part. + * + * The returned object can also be used as a starting point + * to resolve a relative path starting with "@part". + * + * Returns: If @path is the path that led to @obj, the function + * returns the #Object corresponding to "@path/@part". + * If "@path/@part" is not a valid object path, it returns #NULL. + */ +typedef Object *(ObjectPropertyResolve)(Object *obj, + void *opaque, + const char *part); + /** * ObjectPropertyRelease: * @obj: the object that owns the property @@ -321,6 +340,7 @@ typedef struct ObjectProperty gchar *type; ObjectPropertyAccessor *get; ObjectPropertyAccessor *set; + ObjectPropertyResolve *resolve; ObjectPropertyRelease *release; void *opaque; @@ -787,12 +807,16 @@ void object_unref(Object *obj); * destruction. This may be NULL. * @opaque: an opaque pointer to pass to the callbacks for the property * @errp: returns an error if this function fails + * + * Returns: The #ObjectProperty; this can be used to set the @resolve + * callback for child and link properties. */ -void object_property_add(Object *obj, const char *name, const char *type, - ObjectPropertyAccessor *get, - ObjectPropertyAccessor *set, - ObjectPropertyRelease *release, - void *opaque, Error **errp); +ObjectProperty *object_property_add(Object *obj, const char *name, + const char *type, + ObjectPropertyAccessor *get, + ObjectPropertyAccessor *set, + ObjectPropertyRelease *release, + void *opaque, Error **errp); void object_property_del(Object *obj, const char *name, Error **errp); diff --git a/qom/object.c b/qom/object.c index a760514787..7a892ef4a6 100644 --- a/qom/object.c +++ b/qom/object.c @@ -356,11 +356,6 @@ static inline bool object_property_is_child(ObjectProperty *prop) return strstart(prop->type, "child<", NULL); } -static inline bool object_property_is_link(ObjectProperty *prop) -{ - return strstart(prop->type, "link<", NULL); -} - static void object_property_del_all(Object *obj) { while (!QTAILQ_EMPTY(&obj->properties)) { @@ -728,11 +723,12 @@ void object_unref(Object *obj) } } -void object_property_add(Object *obj, const char *name, const char *type, - ObjectPropertyAccessor *get, - ObjectPropertyAccessor *set, - ObjectPropertyRelease *release, - void *opaque, Error **errp) +ObjectProperty * +object_property_add(Object *obj, const char *name, const char *type, + ObjectPropertyAccessor *get, + ObjectPropertyAccessor *set, + ObjectPropertyRelease *release, + void *opaque, Error **errp) { ObjectProperty *prop; @@ -741,7 +737,7 @@ void object_property_add(Object *obj, const char *name, const char *type, error_setg(errp, "attempt to add duplicate property '%s'" " to object (type '%s')", name, object_get_typename(obj)); - return; + return NULL; } } @@ -756,6 +752,7 @@ void object_property_add(Object *obj, const char *name, const char *type, prop->opaque = opaque; QTAILQ_INSERT_TAIL(&obj->properties, prop, node); + return prop; } ObjectProperty *object_property_find(Object *obj, const char *name, @@ -1028,6 +1025,11 @@ static void object_get_child_property(Object *obj, Visitor *v, void *opaque, g_free(path); } +static Object *object_resolve_child_property(Object *parent, void *opaque, const gchar *part) +{ + return opaque; +} + static void object_finalize_child_property(Object *obj, const char *name, void *opaque) { @@ -1041,15 +1043,18 @@ void object_property_add_child(Object *obj, const char *name, { Error *local_err = NULL; gchar *type; + ObjectProperty *op; type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child))); - object_property_add(obj, name, type, object_get_child_property, NULL, - object_finalize_child_property, child, &local_err); + op = object_property_add(obj, name, type, object_get_child_property, NULL, + object_finalize_child_property, child, &local_err); if (local_err) { error_propagate(errp, local_err); goto out; } + + op->resolve = object_resolve_child_property; object_ref(child); g_assert(child->parent == NULL); child->parent = obj; @@ -1163,6 +1168,13 @@ static void object_set_link_property(Object *obj, Visitor *v, void *opaque, } } +static Object *object_resolve_link_property(Object *parent, void *opaque, const gchar *part) +{ + LinkProperty *lprop = opaque; + + return *lprop->child; +} + static void object_release_link_property(Object *obj, const char *name, void *opaque) { @@ -1184,6 +1196,7 @@ void object_property_add_link(Object *obj, const char *name, Error *local_err = NULL; LinkProperty *prop = g_malloc(sizeof(*prop)); gchar *full_type; + ObjectProperty *op; prop->child = child; prop->check = check; @@ -1191,17 +1204,21 @@ void object_property_add_link(Object *obj, const char *name, full_type = g_strdup_printf("link<%s>", type); - object_property_add(obj, name, full_type, - object_get_link_property, - check ? object_set_link_property : NULL, - object_release_link_property, - prop, - &local_err); + op = object_property_add(obj, name, full_type, + object_get_link_property, + check ? object_set_link_property : NULL, + object_release_link_property, + prop, + &local_err); if (local_err) { error_propagate(errp, local_err); g_free(prop); + goto out; } + op->resolve = object_resolve_link_property; + +out: g_free(full_type); } @@ -1260,11 +1277,8 @@ Object *object_resolve_path_component(Object *parent, const gchar *part) return NULL; } - if (object_property_is_link(prop)) { - LinkProperty *lprop = prop->opaque; - return *lprop->child; - } else if (object_property_is_child(prop)) { - return prop->opaque; + if (prop->resolve) { + return prop->resolve(parent, prop->opaque, part); } else { return NULL; } @@ -1571,6 +1585,14 @@ static void property_set_alias(Object *obj, struct Visitor *v, void *opaque, object_property_set(prop->target_obj, v, prop->target_name, errp); } +static Object *property_resolve_alias(Object *obj, void *opaque, + const gchar *part) +{ + AliasProperty *prop = opaque; + + return object_resolve_path_component(prop->target_obj, prop->target_name); +} + static void property_release_alias(Object *obj, const char *name, void *opaque) { AliasProperty *prop = opaque; @@ -1583,6 +1605,7 @@ void object_property_add_alias(Object *obj, const char *name, Error **errp) { AliasProperty *prop; + ObjectProperty *op; ObjectProperty *target_prop; target_prop = object_property_find(target_obj, target_name, errp); @@ -1594,11 +1617,12 @@ void object_property_add_alias(Object *obj, const char *name, 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); + op = object_property_add(obj, name, target_prop->type, + property_get_alias, + property_set_alias, + property_release_alias, + prop, errp); + op->resolve = property_resolve_alias; } static void object_instance_init(Object *obj) -- GitLab