Re: [Qemu-devel] [PATCH 02/18] qapi-types.py: Implement 'base' for unions

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 29 Aug 2013 18:06:50 +0200
Kevin Wolf <kwolf@redhat.com> wrote:

> Am 29.08.2013 um 15:52 hat Luiz Capitulino geschrieben:
> > On Tue, 27 Aug 2013 17:58:59 +0200
> > Kevin Wolf <kwolf@redhat.com> wrote:
> > 
> > > Am 21.08.2013 um 05:38 hat Amos Kong geschrieben:
> > > > On Tue, Jul 23, 2013 at 03:03:10PM +0200, Kevin Wolf wrote:
> > > > > The new 'base' key in a union definition refers to a struct type, which
> > > > > is inlined into the union definition and can represent fields common to
> > > > > all kinds.
> > > > > 
> > > > > For example the following schema definition...
> > > > > 
> > > > >     { 'type': 'BlockOptionsBase', 'data': { 'read-only': 'bool' } }
> > > > > 
> > > > >     { 'union': 'BlockOptions',
> > > > >       'base': 'BlockOptionsBase',
> > > > >       'data': {
> > > > >           'raw': 'BlockOptionsRaw'
> > > > >           'qcow2': 'BlockOptionsQcow2'
> > > > >       } }
> > > > > 
> > > > > ...would result in this generated C struct:
> > > > > 
> > > > >     struct BlockOptions
> > > > >     {
> > > > >         BlockOptionsKind kind;
> > > > >         union {
> > > > >             void *data;
> > > > >             BlockOptionsRaw * raw;
> > > > >             BlockOptionsQcow2 * qcow2;
> > > > >         };
> > > > >         bool read_only;
> > > > >     };
> > > > > 
> > > > > Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> > > > > ---
> > > > >  scripts/qapi-types.py | 16 ++++++++++++++--
> > > > >  1 file changed, 14 insertions(+), 2 deletions(-)
> > > > > 
> > > > > diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
> > > > > index e1239e1..9882b95 100644
> > > > > --- a/scripts/qapi-types.py
> > > > > +++ b/scripts/qapi-types.py
> > > > > @@ -157,7 +157,12 @@ typedef enum %(name)s
> > > > >  
> > > > >      return lookup_decl + enum_decl
> > > > >  
> > > > > -def generate_union(name, typeinfo):
> > > > > +def generate_union(expr):
> > > > > +
> > > > > +    name = expr['union']
> > > > > +    typeinfo = expr['data']
> > > > > +    base = expr.get('base')
> > > > > +
> > > > >      ret = mcgen('''
> > > > >  struct %(name)s
> > > > >  {
> > > > > @@ -176,6 +181,13 @@ struct %(name)s
> > > > >  
> > > > >      ret += mcgen('''
> > > > >      };
> > > > > +''')
> > > > > +
> > > > > +    if base:
> > > > > +        struct = find_struct(base)
> > > > > +        ret += generate_struct_fields(struct['data'])
> > > > 
> > > > 
> > > > generate_struct_fields() doesn't exist in upstream.
> > > > 
> > > > [qemu-upstream]$ grep generate_struct_fields -r *
> > > > scripts/qapi-types.py:        ret += generate_struct_fields(struct['data'])
> > > > [qemu-upstream]$
> > > 
> > > Yup, something went wrong while applying the series, that patch was
> > > simply dropped (and interestingly it didn't result in any conflicts or
> > > compile errors). I'll include it in my next pull request.
> > 
> > Strange, it appears on your pull request... But anyway, your series
> > made it into 1.6.0, so I think we'll need the missing patch in 1.6.1 too?
> 
> There's no user in 1.6 (or would we have a build failure) because I
> didn't merge blockdev-add, so I guess it doesn't matter.

I won't say it's a huge deal, but any downstreamers basing on 1.6 will
have a hard time if they backport blockdev-add or any future command
that my depend on this.