Eric Blake <ebl...@redhat.com> writes:
> On 09/23/2015 08:02 AM, Markus Armbruster wrote:
>
>>> However, I'm not sure it would always help. The conversion of
>>> netdev_add to full qapi relies on being able to access the variant
>>> through a named struct (such as NetdevTapOptions); unboxing the variant
>>> would get rid of the convenient access to these named sub-structs.
>>
>> struct Union {
>> EnumType type;
>> /* union tag is @type */
>> union {
>> One one;
>> Two two;
>> };
>> };
>>
>> For base, we go one step further and peel off the struct, to save some
>> notational overhead. Pointless for unions.
>
> Ah, I see. Instead of malloc'ing a sub-struct and calling (roughly)
>
> ptr = visit_start_struct(Union) // mallocs
> subptr = visit_start_implicit_struct(One) // also mallocs
> visit_type_fields(subptr)
> visit_end_implicit_struct()
>
> we would instead use inline allocation, with:
>
> ptr = visit_start_struct(Union) // mallocs
> visit_type_fields(&ptr->one)
>
> seems straightforward enough; I'll play with the idea on top of my series.
I should be careful what I wish for lest the series grows faster than I
can review it!
