"Dr. David Alan Gilbert" <dgilb...@redhat.com> writes:
> * Markus Armbruster (arm...@redhat.com) wrote:
>> "Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> writes:
>>
>> > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>> >
>> > Avoid a segfault when visiting, e.g., the QOM rtc-time property,
>> > by implementing the struct callbacks and raising an Error.
>> >
>> > Signed-off-by: Andreas Färber <afaer...@suse.de>
>> >
>> > Updated for changed interface:
>> > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
>> > ---
>> > qapi/string-output-visitor.c | 13 +++++++++++++
>> > 1 file changed, 13 insertions(+)
>> >
>> > diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
>> > index 94ac821..4e7e97f 100644
>> > --- a/qapi/string-output-visitor.c
>> > +++ b/qapi/string-output-visitor.c
>> > @@ -12,6 +12,7 @@
>> >
>> > #include "qemu/osdep.h"
>> > #include "qemu-common.h"
>> > +#include "qapi/error.h"
>> > #include "qapi/string-output-visitor.h"
>> > #include "qapi/visitor-impl.h"
>> > #include "qemu/host-utils.h"
>> > @@ -266,6 +267,16 @@ static void print_type_number(Visitor *v, const char
>> > *name, double *obj,
>> > string_output_set(sov, g_strdup_printf("%f", *obj));
>> > }
>> >
>> > +static void start_struct(Visitor *v, const char *name, void **obj, size_t
>> > size,
>> > + Error **errp)
>> > +{
>> > + error_setg(errp, "struct type not implemented");
>> > +}
>> > +
>> > +static void end_struct(Visitor *v, void **obj)
>> > +{
>> > +}
>> > +
>>
>> This is just one of the several things this visitor doesn't implement.
>> See the comment in string-output-visitor.h.
>>
>> String input visitor and options visitor have similar holes; see the
>> comments in string-input-visitor.h and opts-visitor.h.
>>
>> Should we change all of them together to report errors instead of crash?
>> With common "error out because this isn't implemented" methods?
>
> In that case wouldn't it be best to change visit_start_struct/visit_end_struct
> to do the check (Like visit_check_struct does).
In my opinion.
if (v->foo) {
v->foo(...);
} else {
... default action ...
}
is an anti-pattern. Wrap the default action in a default method, and
put that in the function pointer.
