Re: [PATCH 1/3] qapi, audio: add query-audiodev command

[Eric Blake]

On 3/2/21 11:55 AM, Daniel P. Berrangé wrote:
> Way back in QEMU 4.0, the -audiodev command line option was introduced
> for configuring audio backends. This CLI option does not use QemuOpts
> so it is not visible for introspection in 'query-command-line-options',
> instead using the QAPI Audiodev type.  Unfortunately there is also no
> QMP command that uses the Audiodev type, so it is not introspectable
> with 'query-qmp-schema' either.
> 
> This introduces a 'query-audiodev' command that simply reflects back
> the list of configured -audiodev command line options. This in turn
> makes Audiodev introspectable via 'query-qmp-schema'.

Even if we never call the query-audiodev command, its mere existence is
useful ;)

> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  audio/audio.c   | 19 +++++++++++++++++++
>  qapi/audio.json | 13 +++++++++++++
>  2 files changed, 32 insertions(+)


> +AudiodevList *qmp_query_audiodevs(Error **errp)
> +{
> +    AudiodevList *ret = NULL, *prev = NULL, *curr;
> +    AudiodevListEntry *e;
> +    QSIMPLEQ_FOREACH(e, &audiodevs, next) {
> +        curr = g_new0(AudiodevList, 1);
> +        curr->value = QAPI_CLONE(Audiodev, e->dev);
> +        if (prev) {
> +            prev->next = curr;
> +            prev = curr;
> +        } else {
> +            ret = prev = curr;
> +        }

Please use QAPI_LIST_PREPEND here instead of open-coding it.

> +
> +##
> +# @query-audiodevs:
> +#
> +# Returns information about audiodev configuration
> +#
> +# Returns: array of @Audiodev
> +#
> +# Since: 6.0
> +#
> +##
> +{ 'command': 'query-audiodevs',
> +  'returns': ['Audiodev'] }
> 

Otherwise looks nice.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org