Re: [Qemu-devel] [PATCH V5 00/10] qapi script: support enum as discriminator and better enum name

[Luiz Capitulino <lcapitulino@redhat.com>]

On Wed, 22 Jan 2014 11:07:24 -0500
Luiz Capitulino <lcapitulino@redhat.com> wrote:

> On Fri, 20 Dec 2013 13:23:06 +0800
> Wenchao Xia <xiawenc@linux.vnet.ibm.com> wrote:
> 
> > This series address two issues:
> > 
> > 1. support using enum as discriminator in union.
> > For example, if we have following define in qapi schema:
> > { 'enum': 'EnumOne',
> >   'data': [ 'value1', 'value2', 'value3' ] }
> > 
> > { 'type': 'UserDefBase0',
> >   'data': { 'base-string0': 'str', 'base-enum0': 'EnumOne' } }
> > 
> > Before this series, discriminator in union must be a string, and a
> > hidden enum type as discriminator is generated. After this series,
> > qapi schema can directly use predefined enum type:
> > { 'union': 'UserDefEnumDiscriminatorUnion',
> >   'base': 'UserDefBase0',
> >   'discriminator' : 'base-enum0',
> >   'data': { 'value1' : 'UserDefA',
> >             'value2' : 'UserDefInherit',
> >             'value3' : 'UserDefB' } }
> > 
> > The benefit is that every thing is defined explicitly in schema file,
> > the discriminator enum type can be used in other API define in schema,
> > and a compile time check will be put to verify the correctness according
> > to enum define. Currently BlockdevOptions used discriminator which can
> > be converted, in the future other union can also use enum discriminator.
> 
> Applied to the qmp branch, thanks.

Unfortunately this doesn't build anymore due to some block changes that
were merged. Can you please rebase it?

> 
> > 
> > The implement is done by:
> > 1.1 remember the enum defines by qapi scripts.(patch 1)
> > 1.2 use the remembered enum define to check correctness at compile
> > time.(patch 3), more strict check(patch 2)
> > 1.3 use the same enum name generation rule to avoid C code mismatch,
> > esp for "case [ENUM_VALUE]" in qapi-visit.c.(patch 4,5)
> > 1.4 switch the code path, when pre-defined enum type is used as discriminator,
> > don't generate a hidden enum type, use the enum type instead, add
> > docs/qapi-code-gen.txt.(Patch 6)
> > 1.5 test case shows how it looks like.(Patch 7)
> > 1.6 convert BlockdevOptions. (Patch 8)
> > 
> > 2. Better enum name generation
> > Before this patch, AIOContext->A_I_O_CONTEXT, after this patch,
> > AIOContet->AIO_CONTEXT. Since previous patch has foldered enum
> > name generation codes into one function, it is done easily by modifying
> > it.(Patch 9)
> > 
> > 
> > Changes from RFC:
> >   Mainly address Eric's comments: fix typo, add patch 2 to allow partly mapping
> > enum value in union, add related test case, remove direct inherit support "_base"
> > and related test case. RFC series at:
> > http://lists.nongnu.org/archive/html/qemu-devel/2013-11/msg00363.html
> > 
> > v2:
> >   General:
> >   3/8: use Raise exception instead of sys.error.write in qapi.py.
> >   Address Eric's comments:
> >   2/8,3/8: more check for enum value at compile time, not allow partly mapping.
> >   8/8: correspond test case change.
> > 
> > v3:
> >   General:
> >   move enum name generation patch to last in the series, add convert patch
> > 8/9.
> >   Address Luiz and Kevin's comments:
> >   Better introduction.
> >   6/9: renamed this patch, add docs/qapi-code-gen.txt part.
> > 
> > v4:
> >   Address Eric's comments:
> >   5/9: better commit message.
> >   6/9: typo fix in doc.
> >   9/9: typo fix, fix indentation, better incode comment.
> > 
> > v5:
> >   Address Eric's comments:
> >   6/10: doc typo fix.
> >   8/10: new patch to remove string discriminator.
> >   9/10: removed the string discriminator test case.
> > 
> > Wenchao Xia (10):
> >   1 qapi script: remember enum values
> >   2 qapi script: add check for duplicated key
> >   3 qapi script: check correctness of discriminator values in union
> >   4 qapi script: code move for generate_enum_name()
> >   5 qapi script: use same function to generate enum string
> >   6 qapi script: support pre-defined enum type as discriminator in union
> >   7 qapi: convert BlockdevOptions to use enum discriminator
> >   8 qapi script: do not allow string discriminator
> >   9 tests: add cases for inherited struct and union with discriminator
> >   10 qapi script: do not add "_" for every capitalized char in enum
> > 
> >  docs/qapi-code-gen.txt                  |    8 ++-
> >  include/qapi/qmp/qerror.h               |    2 +-
> >  qapi-schema.json                        |   14 ++++-
> >  scripts/qapi-types.py                   |   34 +++++-----
> >  scripts/qapi-visit.py                   |   61 ++++++++++++++---
> >  scripts/qapi.py                         |   84 +++++++++++++++++++++--
> >  target-i386/cpu.c                       |    2 +-
> >  tests/qapi-schema/comments.out          |    2 +-
> >  tests/qapi-schema/qapi-schema-test.json |   22 ++++++
> >  tests/qapi-schema/qapi-schema-test.out  |   13 +++-
> >  tests/test-qmp-input-visitor.c          |   93 +++++++++++++++++++++++++
> >  tests/test-qmp-output-visitor.c         |  116 +++++++++++++++++++++++++++++++
> >  12 files changed, 411 insertions(+), 40 deletions(-)
> > 
>