Re: [Qemu-devel] [PATCH 06/15] piix: create i8254 through composition

[Jan Kiszka]

On 2012-01-31 15:58, Paolo Bonzini wrote:
> On 01/31/2012 03:51 PM, Jan Kiszka wrote:
>>>>
>>>>  BTW, this is yet another benefit of making structures public.  You can 
>>>> take the
>>>>  address of a child and set link fields directly without accessors.
>> Well, that has two sides. We introduced properties to avoid this direct
>> messing.
>>
>> Does linking also work without exposing internals?
> 
> Perhaps it doesn't need to expose internals.  Just like we create 
> interfaces automatically when creating a parent object, perhaps we can 
> create children as well, like
> 
>      TypeInfo type_piix3 = {
>          ...
>          .children = {
>               { "pic[0]", TYPE_I8259, offsetof(PIIX3, pic[0]) },
>               { "pic[1]", TYPE_I8259, offsetof(PIIX3, pic[1]) },
>               { "pit, TYPE_I8254, offsetof(PIIX3, pit) },
>               { "rtc", TYPE_RTC, offsetof(PIIX3, rtc) },
>               { }
>          }

and .links = ...

Yep, such a thing looks better. I suppose that also opens the door for
(runtime) type checking, right?

>      }
> 
> QOM's object_init would allocate a single malloced block for all of 
> them, carve out space for the parent and all children, and add the 
> properties.

Jan

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