Re: [PATCH v6 06/10] qapi: Implement deprecated-output=hide for QMP introspection

[Eric Blake <eblake@redhat.com>]

On 3/12/21 9:32 AM, Markus Armbruster wrote:
> This policy suppresses deprecated bits in output, and thus permits
> "testing the future".  Implement it for QMP command query-qmp-schema:
> suppress information on deprecated commands, events and object type
> members, i.e. anything that has the special feature flag "deprecated".
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> ---
>  monitor/qmp-cmds-control.c | 71 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 71 insertions(+)
> 
> diff --git a/monitor/qmp-cmds-control.c b/monitor/qmp-cmds-control.c
> index 25afd0867f..bcfccc4ac4 100644
> --- a/monitor/qmp-cmds-control.c
> +++ b/monitor/qmp-cmds-control.c
> @@ -158,6 +158,74 @@ EventInfoList *qmp_query_events(Error **errp)
>      return ev_list;
>  }
>  
> +static void *split_off_generic_list(void *list,
> +                                    bool (*splitp)(void *elt),
> +                                    void **part)
> +{
> +    GenericList *keep = NULL, **keep_tailp = &keep;
> +    GenericList *split = NULL, **split_tailp = &split;
> +    GenericList *tail;
> +
> +    for (tail = list; tail; tail = tail->next) {
> +        if (splitp(tail)) {
> +            *split_tailp = tail;
> +            split_tailp = &tail->next;
> +        } else {
> +            *keep_tailp = tail;
> +            keep_tailp = &tail->next;
> +        }
> +    }

At first glance, I wondered if QAPI_LIST_APPEND would be better than
open coding, but with a bit more thought, I agree that this particular
case is best written as presented (you are manipulating two tail
pointers in one iteration, which is different semantics than
QAPI_LIST_APPEND advancing a single tail pointer).

R-b still stands.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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