Re: [Qemu-devel] [PATCH RFC 1/3] qom: Add "realized" property to Object

[Stefan Hajnoczi]

On Mon, Mar 26, 2012 at 2:46 PM, Andreas Färber <address@hidden> wrote:
> The Object::realized property can only be set once and, on setting it,
> invokes the ObjectClass::realize callback.
>
> Signed-off-by: Andreas Färber <address@hidden>
> Cc: Anthony Liguori <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> ---
>  include/qemu/object.h |    2 ++
>  qom/object.c          |   31 +++++++++++++++++++++++++++++++
>  2 files changed, 33 insertions(+), 0 deletions(-)
>
> diff --git a/include/qemu/object.h b/include/qemu/object.h
> index e8fc126..742b5b6 100644
> --- a/include/qemu/object.h
> +++ b/include/qemu/object.h
> @@ -239,6 +239,7 @@ struct ObjectClass
>  {
>     /*< private >*/
>     Type type;
> +    int (*realize)(Object *obj);
>  };
>
>  /**
> @@ -264,6 +265,7 @@ struct Object
>     QTAILQ_HEAD(, ObjectProperty) properties;
>     uint32_t ref;
>     Object *parent;
> +    bool realized;
>  };
>
>  /**
> diff --git a/qom/object.c b/qom/object.c
> index 9cd9506..ec143ad 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -273,6 +273,34 @@ static void object_init_with_type(Object *obj, TypeImpl 
> *ti)
>     }
>  }
>
> +static void object_get_realized(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    visit_type_bool(v, &obj->realized, name, errp);
> +}
> +
> +static void object_set_realized(Object *obj, Visitor *v, void *opaque,
> +                                const char *name, Error **errp)
> +{
> +    bool value;
> +
> +    if (obj->realized) {
> +        error_set(errp, QERR_PERMISSION_DENIED);
> +        return;
> +    }
> +
> +    visit_type_bool(v, &value, name, errp);
> +    if (error_is_set(errp) || !value) {
> +        return;
> +    }
> +
> +    if (obj->class->realize != NULL && obj->class->realize(obj) != 0) {
> +        error_set(errp, QERR_DEVICE_INIT_FAILED, object_get_typename(obj));

->realize() has no way of giving a detailed error.  I think we should
pass in errp.

Stefan