Re: [Qemu-devel] [PATCH v5 01/28] qapi: Document type-safety considerations

[Eric Blake <eblake@redhat.com>]

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On 04/01/2015 09:29 AM, Markus Armbruster wrote:
> Eric Blake <eblake@redhat.com> writes:
> 
> [...]
>>  === Union types ===
>>

>> +
>> +A flat union definition specifies a complex type as its base, and
>> +avoids nesting on the wire.  In this case, the fields of the complex
>> +type are included as top-level fields of the union dictionary in the
>> +QMP wire format, and the 'discriminator' field must be the name of an
>> +enum-typed member of the base type. An example definition is:
>>
>>   { 'type': 'BlockdevCommonOptions', 'data': { 'readonly': 'bool' } }
>>   { 'union': 'BlockdevOptions',
>       'base': 'BlockdevCommonOptions',
>       'data': { 'raw': 'RawOptions',
>                 'qcow2': 'Qcow2Options' } }
> 
> Where's 'discriminator'?

Kevin already flagged this. I forgot to remove simple-with-base
documentation in v5; it's already gone from my working copy of v6.


>    Resulting in this JSON object:
> 
>     { "driver": "qcow2",
>       "readonly": false,
>       "backing-file": "/some/place/my-image",
>       "lazy-refcounts": true }
> 
> This actually matches the above example with the "data" wrapper peeled
> off the variant part.

Yep - with the bad intermediate stuff gone, the remaining stuff makes sense.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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