Commit 64607d08 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ef7c7ff6

include/qom/object.h

+29 −5
Original line number Diff line number Diff line
@@ -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;
@@ -787,8 +807,12 @@ 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,

ObjectProperty *object_property_add(Object *obj, const char *name,

                                    const char *type,

                                    ObjectPropertyAccessor *get,

                                    ObjectPropertyAccessor *set,

                                    ObjectPropertyRelease *release,

qom/object.c

+53 −29
Original line number Diff line number Diff line
@@ -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)) {
@@ -728,7 +723,8 @@ void object_unref(Object *obj) 
    }

}



void object_property_add(Object *obj, const char *name, const char *type,

ObjectProperty *

object_property_add(Object *obj, const char *name, const char *type,

                    ObjectPropertyAccessor *get,

                    ObjectPropertyAccessor *set,

                    ObjectPropertyRelease *release,
@@ -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,

    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;
@@ -1191,7 +1204,7 @@ 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,

    op = object_property_add(obj, name, full_type,

                             object_get_link_property,

                             check ? object_set_link_property : NULL,

                             object_release_link_property,
@@ -1200,8 +1213,12 @@ void object_property_add_link(Object *obj, const char *name, 
    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,

    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)