[Qemu-devel] Re: [PATCH 01/11] QMP: Introduce specification file

[Luiz Capitulino]

On Tue, 23 Jun 2009 16:27:16 +0300
Avi Kivity <address@hidden> wrote:

> On 06/23/2009 04:06 PM, Luiz Capitulino wrote:
> >> I don't see you update that file anywhere.  In any case, my preference
> >> would be to have everything in one file.
> >>      
> >
> >   Sorry, I forgot to mention that I wouldn't include this file
> > in the patchset.
> >    
> 
> You mean now, or forever?

 Only for now, as you noted in another email command porting/additions
should be NACKed if not properly documented.

> >   Ok, as Daniel also said we will need this.
> >
> >   The only problem is that I was trying to avoid changing commands'
> > output too much, because this can turn into a maintenance nightmare.
> >
> >   Note that we will have to maintain two protocols: the current existing
> > (user mode) and this new control mode.
> >    
> 
> I don't see a way out.  The current protocol is not machine consumable, 
> but we can't change it.  We'll just have to live with it.

 Yes.

> >> Clients should never make decisions based on the qemu or qmp version.
> >> Rather, we should provide a facility to query the availability of features.
> >>      
> >
> >   Right. What about changing 'help' output to only list command names?
> >    
> 
> Also command subfeatures, when new subfeatures are added.

 Ok, you suggested a format I'm probably going to use.

> >> Maybe add a numeric error code (to be defined by individual commands).
> >>      
> >
> >   Well, numeric error codes seem redundant in text protocols. At least,
> > POP3 and IMAP don't use them.
> >
> >   This may seem contradictory, but although this a low-level protocol,
> > I feel that text protocols tend to be very descriptive.
> >    
> 
> Well, the strings are not single words, so the key for the application 
> is "all words until the end of the line".  Not too machine friendly.
>