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Date: Mon, 21 May 2012 09:40:41 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] Proposal for extensions of block job commands in
	QEMU 1.2
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, qemu-devel <qemu-devel@nongnu.org>, Luiz Capitulino <lcapitulino@redhat.com>, Federico Simoncelli <fsimonce@redhat.com>, Eric Blake <eblake@redhat.com>

On 05/21/2012 09:26 AM, Paolo Bonzini wrote:
> Il 21/05/2012 16:19, Anthony Liguori ha scritto:
>>>
>>
>> I'm not against it in principle, just in practice.  Today, checking
>> whether a command exists is:
>>
>> commands = qmp.query_commands()
>>
>> if 'block-stream' in commands:
>>      # has block-stream
>>
>> I have a hard time envisioning how schema introspection can be
>> reasonably implemented in a client.
>
> schema = qmp.query_command_schema('block-stream')

What would schema return?

Did you mean:

if schema['arguments'].has_key('on_error'):

What about adding a parameter to a structure?

BTW, the other problem with adding arguments like this is that it makes a stable 
C API impossible.

Regards,

Anthony Liguori

> if 'on-error' in schema:
>      # has on-error
>
> Paolo
>
>