Re: [Qemu-devel] [PATCH] Add 'query-events' command to QMP to query async events

[Daniel P. Berrange]

On Wed, May 16, 2012 at 11:18:22AM -0500, Anthony Liguori wrote:
> On 05/16/2012 11:04 AM, Eric Blake wrote:
> >On 05/16/2012 06:55 AM, Daniel P. Berrange wrote:
> >>From: "Daniel P. Berrange"<address@hidden>
> >>
> >>Sometimes it is neccessary for an application to determine
> >>whether a particular QMP event is available, so they can
> >>decide whether to use compatibility code instead. This
> >>introduces a new 'query-events' command to QMP todo just
> >
> >s/todo/to do/
> >
> >>that
> >>
> >>  { "execute": "query-events" }
> >>  {"return": [{"name": "WAKEUP"},
> >>              {"name": "SUSPEND"},
> >>              {"name": "DEVICE_TRAY_MOVED"},
> >>              {"name": "BLOCK_JOB_CANCELLED"},
> >>              {"name": "BLOCK_JOB_COMPLETED"},
> >>              ...snip...
> >>              {"name": "SHUTDOWN"}]}
> >>
> >>* monitor.c: Split out MonitorEvent ->  string conversion
> >>   into monitor_protocol_event_name() API. Add impl of
> >>   qmp_query_events monitor command handler
> >>* qapi-schema.json, qmp-commands.hx: Define contract of
> >>   query-events command
> >
> >Definitely useful for libvirt.
> >
> >
> >>+static const char *monitor_protocol_event_name(MonitorEvent event)
> >>+{
> >>      switch (event) {
> >>          case QEVENT_SHUTDOWN:
> >>-            event_name = "SHUTDOWN";
> >>+            return "SHUTDOWN";
> >>              break;
> >
> >These 'break' statements are now unreachable; does this matter in qemu
> >coding style?
> 
> Seems like we should just take the opportunity to kill off the
> function entirely and replace it with a table:
> 
> static const char *monitor_event_names[] = {
>  [QEVENT_SHUTDOWN] = "SHUTDOWN",
>  ...
> };

That sounds good to me, I'll update the patch accordingly.

Regards,
Daniel
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