Re: [Qemu-devel] QMP interface for drive-add (or even blockdev-add)

[Stefan Hajnoczi]

On Thu, May 23, 2013 at 4:41 PM, Kevin Wolf <address@hidden> wrote:
> Am 23.05.2013 um 13:57 hat Stefan Hajnoczi geschrieben:
>> On Wed, May 22, 2013 at 03:53:05PM +0200, Kevin Wolf wrote:
>> > Am 16.05.2013 um 21:05 hat Eric Blake geschrieben:
>> > > On 05/16/2013 02:24 AM, Kevin Wolf wrote:
>> > The other thing that I'm not sure about is whether we should teach QAPI
>> > to parse certain data structures just into QDicts instead of C structs,
>> > or if dealing with the big unions inside the block layer actually makes
>> > sense.
>>
>> This is an interesting question.  It's very convenient from the code
>> side - we don't have to worry about laying down a schema.
>>
>> However, the point of QAPI is to offer that schema that allows for us to
>> reason about things like compatibility (hard to sneak in a patch that
>> modifies the schema, easy to sneak in a patch that modifies block driver
>> parameter code) and eliminates the boilerplate of type-checking/basic
>> input validation.
>>
>> Even if it requires some effort, I think we should avoid tunneling
>> schema-less data over QAPI.
>
> Note that I'm talking _only_ about the C side here. Everything that goes
> through QMP is an external API and must described by a schema, I fully
> agree there.
>
> The question is whether QAPI must, after validating the input against
> the schema, parse it into C structs or whether it should be able to fill
> QDicts and pass those around.

I see.  In that case using a QDict seems fine.

Stefan