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Date: Tue, 31 Jan 2012 15:58:12 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 06/15] piix: create i8254 through
	composition
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Anthony Liguori <aliguori@us.ibm.com>, Markus Armbruster <armbru@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>

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) },
              { }
         }
     }

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.

Paolo