Re: [Qemu-devel] [RFC PATCH v1 3/7] qdev-core: Introduce DEVICE super class cast macros

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Jun 18, 2013 at 07:45:36PM +1000, peter.crosthwaite@xilinx.com wrote:
> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> 
> Add macros DEVICE_SUPER_CLASS and DEVICE_GET_SUPER_CLASS. These are the
> similar to their respective non SUPER versions, except instead of
> returning the class object for the concrete class, they return their
> parent classes implementation (usually some form of abstract class).
> 
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> ---
> 
>  include/hw/qdev-core.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index 7fbffcb..96647c4 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -16,6 +16,10 @@ enum {
>  #define DEVICE(obj) OBJECT_CHECK(DeviceState, (obj), TYPE_DEVICE)
>  #define DEVICE_CLASS(klass) OBJECT_CLASS_CHECK(DeviceClass, (klass), TYPE_DEVICE)
>  #define DEVICE_GET_CLASS(obj) OBJECT_GET_CLASS(DeviceClass, (obj), TYPE_DEVICE)
> +#define DEVICE_SUPER_CLASS(klass, typename) \
> +    DEVICE_CLASS(object_class_get_super(OBJECT_CLASS(klass), typename))
> +#define DEVICE_GET_SUPER_CLASS(obj, typename) \
> +    DEVICE_SUPER_CLASS(DEVICE_GET_CLASS(obj), typename)

DEVICE_GET_SUPER_CLASS is not a great name. It actually gets you
a device not a class.

I know this mirrors DEVICE_GET_CLASS that's not
a great name too.

Generally in cases where we change the type of object but in fact return
same pointer, it would be better to rename _GET to _CAST I think.

>  
>  typedef int (*qdev_initfn)(DeviceState *dev);
>  typedef int (*qdev_event)(DeviceState *dev);
> -- 
> 1.8.3.rc1.44.gb387c77.dirty