Re: [Qemu-devel] [PATCH V2 0/8] qapi script: support enum as discriminator and better enum name

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 28 Nov 2013 14:19:48 +0800
Wenchao Xia <xiawenc@linux.vnet.ibm.com> wrote:

> 于 2013/11/26 0:47, Luiz Capitulino 写道:
> > On Wed, 13 Nov 2013 06:25:00 +0800
> > Wenchao Xia <xiawenc@linux.vnet.ibm.com> wrote:
> >
> >> This series is respined from RFC series at:
> >> http://lists.nongnu.org/archive/html/qemu-devel/2013-11/msg00363.html
> >>
> >> Patch 1-6 add support for enum as discriminator.
> >> Patch 7 improve enum name generation, now AIOContext->AIO_CONTEXT, X86CPU->
> >> X86_CPU.
> >> Patch 8 are the test cases.
> >
> > Can you please clarify what is the problem this series is trying to
> > solve, how it does it and provide before/after type of examples?
> >
> > That's what I'd expect from an intro email, but this one has only a
> > reference to an RFC series that has no better info, and some crypt
> > changelog with magic numbers :(
> >
> > Besides, this doesn't apply anymore...
> >
>    Let me have an introduction:
> 
> 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' } }

OK, now tell me who will benefit from this. You don't have to answer
right now, you can resend your series with this information. Note that
I'm not asking to be convinced, I'm asking to have enough info so that
I can understand what this is about when I get to review this (and this
is just what an intro email is about).

> 
> 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)
> 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 when pre-defined enum type is used as discriminator, don't generate
> a hidden enum type, switch the code path to support enum as
> discriminator.
> 1.5 test case shows how it looks like.(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 7)
> 
> >>
> >> 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.
> >>
> >> v2:
> >>    General:
> >>    3: use Raise exception instead of sys.error.write in qapi.py.
> >>    Address Eric's comments:
> >>    2,3: more check for enum value at compile time.
> >>    8: correspond test case change.
> >>
> >> Wenchao Xia (8):
> >>    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: not generate hidden enum type for pre-defined enum discriminator
> >>    7 qapi script: do not add "_" for every capitalized char in enum
> >>    8 tests: add cases for inherited struct and union with discriminator
> >>
> >>   include/qapi/qmp/qerror.h               |    2 +-
> >>   scripts/qapi-types.py                   |   34 ++++----
> >>   scripts/qapi-visit.py                   |   55 +++++++++--
> >>   scripts/qapi.py                         |   84 ++++++++++++++++-
> >>   target-i386/cpu.c                       |    2 +-
> >>   tests/qapi-schema/comments.out          |    2 +-
> >>   tests/qapi-schema/qapi-schema-test.json |   27 ++++++
> >>   tests/qapi-schema/qapi-schema-test.out  |   15 +++-
> >>   tests/test-qmp-input-visitor.c          |  120 +++++++++++++++++++++++++
> >>   tests/test-qmp-output-visitor.c         |  149 +++++++++++++++++++++++++++++++
> >>   10 files changed, 454 insertions(+), 36 deletions(-)
> >>
> >
>