Hi,
Am 08.06.2013 04:22, schrieb Peter Crosthwaite:
> On Sat, Jun 8, 2013 at 4:18 AM, Andreas Färber <afaer...@suse.de> wrote:
>> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
>> index dc6f4e4..409d315 100644
>> --- a/hw/9pfs/virtio-9p-device.c
>> +++ b/hw/9pfs/virtio-9p-device.c
[...]
>> @@ -136,12 +138,16 @@ static Property virtio_9p_properties[] = {
>> DEFINE_PROP_END_OF_LIST(),
>> };
>>
>> -static void virtio_9p_class_init(ObjectClass *klass, void *data)
>> +static void virtio_9p_class_init(ObjectClass *oc, void *data)
>> {
>> - DeviceClass *dc = DEVICE_CLASS(klass);
>> - VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
>> + DeviceClass *dc = DEVICE_CLASS(oc);
>> + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(oc);
>> + V9fsClass *v9c = VIRTIO_9P_CLASS(oc);
>> +
>> + v9c->parent_realize = dc->realize;
>> + dc->realize = virtio_9p_device_realize;
>> +
>> dc->props = virtio_9p_properties;
>> - vdc->init = virtio_9p_device_init;
>> vdc->get_features = virtio_9p_get_features;
>> vdc->get_config = virtio_9p_get_config;
>> }
>> @@ -151,6 +157,7 @@ static const TypeInfo virtio_device_info = {
>> .parent = TYPE_VIRTIO_DEVICE,
>> .instance_size = sizeof(V9fsState),
>> .class_init = virtio_9p_class_init,
>> + .class_size = sizeof(V9fsClass),
>> };
>>
>> static void virtio_9p_register_types(void)
>> diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
>> index 1d6eedb..85699a7 100644
>> --- a/hw/9pfs/virtio-9p.h
>> +++ b/hw/9pfs/virtio-9p.h
>> @@ -227,6 +227,15 @@ typedef struct V9fsState
>> V9fsConf fsconf;
>> } V9fsState;
>>
>> +typedef struct V9fsClass {
>> + /*< private >*/
>> + VirtioDeviceClass parent_class;
>> + /*< public >*/
>> +
>> + DeviceRealize parent_realize;
>> +} V9fsClass;
>> +
>> +
>
> If applied tree-wide this change pattern is going to add a lot of
> boiler-plate to all devices. There is capability in QOM to access the
> overridden parent class functions already, so it can be made to work
> without every class having to do this save-and-call trick with
> overridden realize (and friends). How about this:
>
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 9190a7e..696702a 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -37,6 +37,18 @@ int qdev_hotplug = 0;
> static bool qdev_hot_added = false;
> static bool qdev_hot_removed = false;
>
> +void device_parent_realize(DeviceState *dev, Error **errp)
> +{
> + ObjectClass *class = object_get_class(dev);
> + DeviceClass *dc;
> +
> + class = object_class_get_parent(dc);
> + assert(class);
> + dc = DEVICE_CLASS(class);
> +
> + dc->realize(dev, errp);
> +}
> +
>
> And child class realize fns can call this to realize themselves as the
> parent would. Ditto for reset and unrealize. Then you would only need
> to define struct FooClass when creating new abstractions (or virtual
> functions if your C++).
Indeed, if you check the archives you will find that I suggested the
same in the context of ISA i8254/i8259 or CPUState. ;) Yet Anthony
specifically instructed me to do it this way, referring to GObject.
I then documented the expected process in qdev-core.h and object.h.
Regards,
Andreas
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