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Date: Thu, 10 Dec 2009 09:52:37 -0200
From: Luiz Capitulino <lcapitulino@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 10/19] monitor: Convert do_info_name() to
	QObject
Message-ID: <20091210095237.38cafe5c@doriath>
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To: Markus Armbruster <armbru@redhat.com>
Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org

On Thu, 10 Dec 2009 11:09:53 +0100
Markus Armbruster <armbru@redhat.com> wrote:

> Luiz Capitulino <lcapitulino@redhat.com> writes:
> 
> > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> > ---
> >  monitor.c |   29 +++++++++++++++++++++++++----
> >  1 files changed, 25 insertions(+), 4 deletions(-)
> >
> > diff --git a/monitor.c b/monitor.c
> > index 47f794d..3d33bd8 100644
> > --- a/monitor.c
> > +++ b/monitor.c
> > @@ -514,10 +514,30 @@ static void do_info_version(Monitor *mon, QObject **ret_data)
> >                                     QEMU_VERSION, QEMU_PKGVERSION);
> >  }
> >  
> > -static void do_info_name(Monitor *mon)
> > +static void do_info_name_print(Monitor *mon, const QObject *data)
> >  {
> > -    if (qemu_name)
> > -        monitor_printf(mon, "%s\n", qemu_name);
> > +    const char *str;
> > +
> > +    str = qdict_get_str(qobject_to_qdict(data), "name");
> > +    if (strlen(str) > 0) {
> > +        monitor_printf(mon, "%s\n", str);
> > +    }
> > +}
> > +
> > +/**
> > + * do_info_name(): Show VM name
> > + *
> > + * Return a QDict with the following information:
> > + *
> > + * - "name": VM's name. If the VM has no name, the string will be empty
> 
> So you can't distinguish name "" from unnamed.  Do we care?

 I don't think so, but if we do the best way to deal with the fact
that qemu_name can be NULL would be to return null, like:

{ "name": null }

 But we don't support json-null yet... There are other two
ways to solve this, but they seem workarounds for not supporting
null: return an empty dict or return { "name": false }.

> Monitor output for unnamed guests changes from
> 
>     (qemu) info name
>     (qemu) 
> 
> to
> 
> (qemu) info name
> 
> (qemu) 

 The strlen() call doesn't let this happen. Although the
other way around does happen: if you call qemu with -name '',
then output would be:

(qemu) info name

(qemu)

 This won't happen anymore, goto do_we_care.