Re: [Qemu-devel] [PATCH 06/29] monitor: New format for handlers argument types

[Anthony Liguori]

Luiz Capitulino wrote:
> On Mon, 24 Aug 2009 18:21:17 +0200
> Markus Armbruster <address@hidden> wrote:
>
>   
> > Luiz Capitulino <address@hidden> writes:
> >
> >     
> > > Current handlers argument types, as defined in qemu-monitor.hx file,
> > > are a sequence of chars where each one represents one argument type
> > > of the command handler. The number of chars is also used to know how
> > > many arguments a given handler accepts.
> > >
> > > This commit defines a new format, which makes mandatory the use of
> > > a name for each argument.
> > >
> > > For example, do_eject() command handler is currently defined as:
> > >
> > > { "eject", "-fB", do_eject, ... }
> > >
> > > With the new format it becomes:
> > >
> > > { "eject", "force:-f,filename:B", do_eject, ... }
> > >
> > > This way the Monitor will be capable of setting up a dictionary, using
> > > each argument's name as the key and the argument itself as the value.
> > >
> > > This commit also adds two new functions: key_get_info() and
> > > next_arg_type(), both are used to parse the new format.
> > >
> > > Currently key_get_info() consumes the 'key' part of the new format and
> > > discards it, this way the current parsing code is not affected by this
> > > change.
> > >
> > > Signed-off-by: Luiz Capitulino <address@hidden>
> > >       
> > Encoding the parameter list in a single args_type made perfect sense
> > when a parameter was encoded in one or two characters.  But having
> > syntax and a parser... I don't know.  Switch to an array of parameter
> > descriptions that don't need to be parsed?
> >     
>
>  I don't see how to do this w/o parsing, but anyway I think we should
> be practical here and use what already exists.
>   
I agree with Markus.  I think we can start with this approach but I'd 
like to see it changed in the near future.  Instead of having:

{ "eject", "force:-f,filename:B", do_eject, ... }

I would expect something like:

{ .name = "eject",
  .args = (MonitorArgs[]){
      { .name = "force",
         .short = 'f',
         .type = MON_FLAG },
   {}},
  .func = do_eject,
}

Macros can be used to simplify things but I think this is the general 
idea that Markus was suggesting.

Regards,

Anthony Liguori