Re: [PATCH 2/3] qom: move user_creatable_add_opts logic to vl.c and QAPIfy it

[Eric Blake <eblake@redhat.com>]

On 3/11/21 11:24 AM, Paolo Bonzini wrote:
> Emulators are currently using OptsVisitor (via user_creatable_add_opts)
> to parse the -object command line option.  This has one extra feature,
> compared to keyval, which is automatic conversion of integers to lists
> as well as support for lists as repeated options:
> 
>   -object memory-backend-ram,id=pc.ram,size=1048576000,host-nodes=0,policy=bind
> 
> So we cannot replace OptsVisitor with keyval right now.  Still, this
> patch moves the user_creatable_add_opts logic to vl.c since it is
> not needed anywhere else, and makes it go through user_creatable_add_qapi.
> 
> In order to minimize code changes, the predicate still takes a string.
> This can be changed later to use the ObjectType QAPI enum directly.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/qom/object_interfaces.h | 50 ++--------------------
>  qom/object_interfaces.c         | 57 +------------------------
>  softmmu/vl.c                    | 73 +++++++++++++++++++++++++--------
>  3 files changed, 60 insertions(+), 120 deletions(-)
> 

> @@ -1684,6 +1691,48 @@ static int machine_set_property(void *opaque,
>      return object_parse_property_opt(opaque, name, value, "type", errp);
>  }
>  
> +static void object_option_foreach_add(bool (*type_opt_predicate)(const char *), Error **errp)

Should this return a bool...

> +{
> +    ObjectOption *opt, *next;
> +
> +    QTAILQ_FOREACH_SAFE(opt, &object_opts, next, next) {
> +        const char *type = ObjectType_str(opt->opts->qom_type);
> +        if (type_opt_predicate(type)) {
> +            if (!user_creatable_add_qapi(opt->opts, errp)) {
> +                return;

with return false here,

> +            }
> +            qapi_free_ObjectOptions(opt->opts);
> +            QTAILQ_REMOVE(&object_opts, opt, next);
> +        }
> +    }

and true here, to make it easier for callers to detect failure without
having to inspect errp?

> +}
> +
> +static void object_option_parse(const char *optarg)

> @@ -1815,9 +1860,7 @@ static void qemu_create_early_backends(void)
>          exit(1);
>      }
>  
> -    qemu_opts_foreach(qemu_find_opts("object"),
> -                      user_creatable_add_opts_foreach,
> -                      object_create_early, &error_fatal);
> +    object_option_foreach_add(object_create_early, &error_fatal);

Then again, since the only callers pass error_fatal, we never reach the
early return.

Reviewed-by: Eric Blake <eblake@redhat.com>

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