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

[Anthony Liguori <anthony@codemonkey.ws>]

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"<berrange@redhat.com>
>>
>> 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",
  ...
};

Regards,

Anthony Liguori