Re: [Qemu-devel] [PATCH qom-next 6/7] qom: Add "realized" property

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/08/2012 03:31 AM, Andreas Färber wrote:
> From: Paolo Bonzini<pbonzini@redhat.com>
>
> Since we had to move the state field from DeviceState to Object, we cannot
> delay the implementation of the "realized" property.  The property is
> a trigger for two actions that propagate through the composition tree.
> "Realize" is called when the property becomes true, and propagates in
> pre-order; realize can fail if the values of the properties are not valid.
> "Unrealize" is called when the property becomes false, and propagates in
> post-order; unrealize cannot fail.
>
> Realize/unrealize is separate from reset.  Reset propagation is a thorny
> issue of its own.  We expect classes that care to implement a reset method
> and call it from realize or realize_children, depending on whether
> pre-order or post-order is more appropriate.
>
> This patch adds four methods (realize, realize_children, unrealize,
> unrealize_children) to ObjectClass, together with a default implementation
> of realize_children and unrealize_children.
>
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> Signed-off-by: Andreas Färber<afaerber@suse.de>

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>

Regards,

Anthony Liguori

> ---
>   include/qemu/object.h |   20 +++++++++++
>   qom/object.c          |   89 +++++++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 109 insertions(+), 0 deletions(-)
>
> diff --git a/include/qemu/object.h b/include/qemu/object.h
> index 4ea1187..05ea711 100644
> --- a/include/qemu/object.h
> +++ b/include/qemu/object.h
> @@ -246,6 +246,10 @@ struct ObjectClass
>       /*<  public>*/
>       Property *props;
>       const char *(*get_id)(Object *);
> +    void (*realize)(Object *obj, struct Error **errp);
> +    void (*realize_children)(Object *obj, struct Error **errp);
> +    void (*unrealize)(Object *obj);
> +    void (*unrealize_children)(Object *obj);
>   };
>
>   typedef enum ObjectState {
> @@ -464,6 +468,22 @@ Object *object_new_with_type(Type type);
>   void object_delete(Object *obj);
>
>   /**
> + * object_realize_children:
> + * @obj: The object whose children should be realized.
> + *
> + * The default implementation of realize_children.
> + */
> +void object_realize_children(Object *obj, struct Error **errp);
> +
> +/**
> + * object_unrealize_children:
> + * @obj: The object whose children should be unrealize.
> + *
> + * The default implementation of unrealize_children.
> + */
> +void object_unrealize_children(Object *obj);
> +
> +/**
>    * object_initialize_with_type:
>    * @obj: A pointer to the memory to be used for the object.
>    * @type: The type of the object to instantiate.
> diff --git a/qom/object.c b/qom/object.c
> index a639348..40bc23a 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -265,6 +265,87 @@ static void object_interface_init(Object *obj, InterfaceImpl *iface)
>       obj->interfaces = g_slist_prepend(obj->interfaces, iface_obj);
>   }
>
> +static void object_get_realized(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    bool value = object_is_realized(obj);
> +
> +    visit_type_bool(v,&value, name, errp);
> +}
> +
> +static void object_unrealize(Object *obj)
> +{
> +    ObjectClass *klass = object_get_class(obj);
> +
> +    if (klass->unrealize_children) {
> +        klass->unrealize_children(obj);
> +    }
> +    if (obj->state != OBJECT_STATE_INITIALIZED&&  klass->unrealize) {
> +        klass->unrealize(obj);
> +    }
> +    obj->state = OBJECT_STATE_INITIALIZED;
> +}
> +
> +static int object_unrealize_one(Object *obj, void *unused)
> +{
> +    object_unrealize(obj);
> +    return 0;
> +}
> +
> +void object_unrealize_children(Object *obj)
> +{
> +    object_child_foreach(obj, object_unrealize_one, NULL);
> +}
> +
> +static void object_realize(Object *obj, Error **errp)
> +{
> +    ObjectClass *klass = object_get_class(obj);
> +
> +    if (obj->state != OBJECT_STATE_REALIZED&&  klass->realize) {
> +        klass->realize(obj, errp);
> +    }
> +    obj->state = OBJECT_STATE_REALIZED;
> +    if (klass->realize_children) {
> +        klass->realize_children(obj, errp);
> +    }
> +}
> +
> +static int object_realize_one(Object *obj, void *errp)
> +{
> +    Error *err = NULL;
> +    object_realize(obj,&err);
> +    if (err) {
> +        error_propagate((Error **)errp, err);
> +        return 1;
> +    }
> +
> +    return 0;
> +}
> +
> +void object_realize_children(Object *obj, Error **errp)
> +{
> +    object_child_foreach(obj, object_realize_one, errp);
> +}
> +
> +static void object_set_realized(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    bool value;
> +    Error *err = NULL;
> +
> +    visit_type_bool(v,&value, name,&err);
> +    if (err) {
> +        error_propagate(errp, err);
> +        return;
> +    }
> +
> +    if (value) {
> +        object_realize(obj, errp);
> +    } else {
> +        object_unrealize(obj);
> +    }
> +}
> +
>   static void object_init_with_type(Object *obj, TypeImpl *ti)
>   {
>       int i;
> @@ -373,6 +454,8 @@ void object_unparent(Object *obj)
>
>   static void object_deinit(Object *obj, TypeImpl *type)
>   {
> +    object_property_set_bool(obj, false, "realized", NULL);
> +
>       if (type->instance_finalize) {
>           type->instance_finalize(obj);
>       }
> @@ -1277,6 +1360,9 @@ static void object_instance_init(Object *obj)
>
>       object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
>
> +    object_property_add(obj, "realized", "bool", object_get_realized,
> +                        object_set_realized, NULL, NULL, NULL);
> +
>       class = object_get_class(obj);
>       do {
>           for (prop = OBJECT_CLASS(class)->props; prop&&  prop->name; prop++) {
> @@ -1289,6 +1375,8 @@ static void object_instance_init(Object *obj)
>   static void object_class_init(ObjectClass *klass, void *class_data)
>   {
>       klass->get_id = object_instance_get_id;
> +    klass->realize_children = object_realize_children;
> +    klass->unrealize_children = object_unrealize_children;
>   }
>
>   static void register_types(void)
> @@ -1303,6 +1391,7 @@ static void register_types(void)
>           .name = TYPE_OBJECT,
>           .instance_size = sizeof(Object),
>           .class_base_init = object_class_base_init,
> +        .class_init = object_class_init,
>           .instance_init = object_instance_init,
>           .class_init = object_class_init,
>           .abstract = true,