On 02/23/2016 07:50 AM, Daniel P. Berrange wrote: > On Fri, Feb 19, 2016 at 01:18:05PM +0100, Markus Armbruster wrote: >> From: Eric Blake <ebl...@redhat.com> >> >> There's no reason to do two malloc's for a flat union; let's just >> inline the branch struct directly into the C union branch of the >> flat union. >>
> > My code needs todo something a little different though - it needs > to directly visit one of the union branches. Previously, I could > allocate a QCryptoBlockOptions and then visit a specific union > branch like this: > > QCryptoBlockOptions *opts = NULL; > > opts = g_new0(QCryptoBlockOptions, 1); > opts.format = Q_CRYPTO_BLOCK_FORMAT_LUKS > > visit_type_QCryptoBlockOptionsLUKS(v, "luks", &opts.u.luks, errp) which allocated a pointer and visited the fields. We no longer need the pointer, but still need the fields visited. > > > I need todo this, because my visitor instance does not have any > 'format' field to visit - we know the format upfront from the > block layer driver choice. So we need to directly visit the > appropriate inline union branch. This no longer works, because > the opts.u.luks field is now inlined instead of being boxed :-( You're using OptsVisitor, right? Is it possible to hack the QemuOpts that you feed to opts_visitor_new() to include a 'format' field? > > I could visit_type_QCryptoBlockOptionsLUKS_fields(v, opts.u.luks, errp) > but the '_fields' methods are all declared static in qapi-visit.c > preventing their use. > > IMHO, now that QAPI inlines the flat unions, we should be making > the _fields() methods public. But my suggestion would just be a hack. Yours makes more sense in the long run, so I'll go ahead and propose that patch. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature
