Re: [Qemu-devel] [PATCH v2 5/6] qapi: generate list struct and visit_list for enum

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On Wed, Jun 06, 2012 at 03:40:37PM -0300, Luiz Capitulino wrote:
> On Sat,  2 Jun 2012 06:54:27 +0800
> Amos Kong <akong@redhat.com> wrote:
> 
> > Currently, if define an 'enum' and use it in one command's data,
> > List struct for enum could not be generated, but it's used in
> > qmp function.
> > 
> > For example: KeyCodesList could not be generated.
> > >>> qapi-schema.json:
> > { 'enum': 'KeyCodes',
> >   'data': [ 'shift', 'alt' ... ] }
> > { 'command': 'sendkey',
> >   'data': { 'keys': ['KeyCodes'], '*hold-time': 'int' } }
> > 
> > >>> qmp-command.h:
> > void qmp_sendkey(KeyCodesList * keys, bool has_hold_time, int64_t
> > hold_time, Error **errp);
> > 
> > This patch makes qapi can generate List struct for enum.
> 
> This patch does it the simple way, just like any type. It generates a enum list
> type and the functions qapi_free_yourenum() and qapi_free_yourenumlist().

Had a couple suggestions, but approach/patch seems reasonable to me.

> 
> The qapi_free_yourenum() list ends up doing nothing, so it could be a good
> idea to generate an empty body (also note that we're copying the argument's
> value, this could bite us in the future).

I think we can omit qapi_free_yourenum() completely. Humans will know
not to free non-allocated types, and the generated marshallers
don't use these interfaces.

> 
> Another point I was wondering is that, all enums will end up having the
> exact same code. So maybe we could generate a default int list and use it
> for all enums. Not sure it's worth it though.

Since it's generated code I don't think it's worth it, personally.

> 
> Michael, Paolo, ideas?
> 
> More review comments below.
> 
> 
> > 
> > Signed-off-by: Amos Kong <akong@redhat.com>
> > ---
> >  scripts/qapi-types.py |   33 +++++++++++++++++++++++++++++----
> >  scripts/qapi-visit.py |   14 +++++++++-----
> >  2 files changed, 38 insertions(+), 9 deletions(-)
> > 
> > diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
> > index 4a734f5..c9641fb 100644
> > --- a/scripts/qapi-types.py
> > +++ b/scripts/qapi-types.py
> > @@ -16,17 +16,36 @@ import os
> >  import getopt
> >  import errno
> >  
> > -def generate_fwd_struct(name, members):
> > -    return mcgen('''
> > +def generate_fwd_struct(name, members, enum=False):
> 
> I think it's better to have generate_fwd_enum_struct().
> 
> > +    ret = ""
> > +    if not enum:
> > +        ret += mcgen('''
> >  typedef struct %(name)s %(name)s;
> >  
> > +''',
> > +                     name=name)
> > +    ret += mcgen('''
> >  typedef struct %(name)sList
> >  {
> > -    %(name)s *value;
> > +''',
> > +                     name=name)
> > +    if enum:
> > +        ret += mcgen('''
> > +         %(name)s value;
> > +''',
> > +                     name=name)
> > +    else:
> > +        ret += mcgen('''
> > +         %(name)s * value;
> > +''',
> > +                     name=name)
> > +
> > +    ret += mcgen('''
> >      struct %(name)sList *next;
> >  } %(name)sList;
> >  ''',
> >                   name=name)
> > +    return ret
> >  
> >  def generate_struct(structname, fieldname, members):
> >      ret = mcgen('''
> > @@ -265,7 +284,8 @@ for expr in exprs:
> >      if expr.has_key('type'):
> >          ret += generate_fwd_struct(expr['type'], expr['data'])
> >      elif expr.has_key('enum'):
> > -        ret += generate_enum(expr['enum'], expr['data'])
> > +        ret += generate_enum(expr['enum'], expr['data']) + "\n"
> 
> The new-line should be returned by generate_enum(). Same applies for the
> occurrences below.
> 
> > +        ret += generate_fwd_struct(expr['enum'], expr['data'], True)
> >          fdef.write(generate_enum_lookup(expr['enum'], expr['data']))
> >      elif expr.has_key('union'):
> >          ret += generate_fwd_struct(expr['union'], expr['data']) + "\n"
> > @@ -289,6 +309,11 @@ for expr in exprs:
> >          fdef.write(generate_type_cleanup(expr['union'] + "List") + "\n")
> >          ret += generate_type_cleanup_decl(expr['union'])
> >          fdef.write(generate_type_cleanup(expr['union']) + "\n")
> > +    elif expr.has_key('enum'):
> > +        ret += generate_type_cleanup_decl(expr['enum'] + "List")
> > +        fdef.write(generate_type_cleanup(expr['enum'] + "List") + "\n")
> > +        ret += generate_type_cleanup_decl(expr['enum'])
> > +        fdef.write(generate_type_cleanup(expr['enum']) + "\n")
> >      else:
> >          continue
> >      fdecl.write(ret)
> > diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
> > index 8d4e94a..e44edfa 100644
> > --- a/scripts/qapi-visit.py
> > +++ b/scripts/qapi-visit.py
> > @@ -81,7 +81,7 @@ end:
> >  ''')
> >      return ret
> >  
> > -def generate_visit_list(name, members):
> > +def generate_visit_list(name, members, enum=False):
> >      return mcgen('''
> >  
> >  void visit_type_%(name)sList(Visitor *m, %(name)sList ** obj, const char *name, Error **errp)
> > @@ -160,12 +160,14 @@ end:
> >  
> >      return ret
> >  
> > -def generate_declaration(name, members, genlist=True):
> > -    ret = mcgen('''
> > +def generate_declaration(name, members, genlist=True, enum=False):
> > +    ret = ""
> > +    if not enum:
> > +        ret = mcgen('''
> >  
> >  void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp);
> >  ''',
> > -                name=name)
> > +                    name=name)
> 
> Why this change?
> 
> >  
> >      if genlist:
> >          ret += mcgen('''
> > @@ -293,10 +295,12 @@ for expr in exprs:
> >          ret += generate_declaration(expr['union'], expr['data'])
> >          fdecl.write(ret)
> >      elif expr.has_key('enum'):
> > -        ret = generate_visit_enum(expr['enum'], expr['data'])
> > +        ret = generate_visit_list(expr['enum'], expr['data'], True)
> > +        ret += generate_visit_enum(expr['enum'], expr['data'])
> >          fdef.write(ret)
> >  
> >          ret = generate_decl_enum(expr['enum'], expr['data'])
> > +        ret += generate_declaration(expr['enum'], expr['data'], enum=True)
> >          fdecl.write(ret)
> >  
> >  fdecl.write('''
> 
>