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

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 07 Jun 2012 10:52:46 +0800
Amos Kong <akong@redhat.com> wrote:

> On 07/06/12 08:26, Michael Roth wrote:
> > 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.
> 
> 
> Thanks for your review!
> 
> >>> 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().
> 
> I tried this before, too many duplicate codes would be introduced,
> but it's more clear.

You could try to move the duplicated code to a third function (or move
the specific bits to generate_fwd_enum_struct() and generate_enum_declaration()).

> 
> two functions need to be added
>    qapi-types.py: def generate_fwd_enum_struct(name, members):
>    qapi-visit.py: def generate_enum_declaration(name, members, 
> genlist=True):
> 
> >>> +    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.
> 
> 
> "\n" is used to add a blank line here.
> 
> >>> +        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?
> 
> 
> Indent of above "mcgen(" changes, make them aligned.
> 
> >>>
> >>>       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('''
> >>
> >>
>