Re: [Qemu-devel] [PATCH RFC 03/10] qapi script: check correctness of discriminator values in union

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013/11/5 21:25, Eric Blake 写道:
> On 11/04/2013 05:37 PM, Wenchao Xia wrote:
>> It will check whether the values specfied are wrotten correctly when
>
> s/specfied/specified/
> s/wrotten/written/
>
>> discriminator is a pre-defined enum type, which help check whether the
>> schema is in good form.
>>
>> It is allowed that, not every value in enum is used, so do not check
>
> s/that,/that/
>
>> that case.
>
> Why do you allow partial coverage?  That feels like an accident waiting
> to happen.  Does the user get a sane error message if they request an
> enum value that wasn't mapped to a union branch?  I think it would be
> wiser to mandate that if the discriminator is an enum, then the union
> must cover all values of the enum.
>
   abort() will be called in qapi-visit.c, it is OK for output visitor,
but bad for input visitor since user input may trigger it. I think
change abort() to error_set() could solve the problem, then we allow
map part of enum value.

>> +
>> +# Return the descriminator enum define, if discriminator is specified in
>
> s/descriminator/discriminator/
>
>> +# @expr and it is a pre-defined enum type
>> +def descriminator_find_enum_define(expr):
>
> s/descriminator/discriminator/ - and fix all callers
>
>> +    discriminator = expr.get('discriminator')
>> +    base = expr.get('base')
>> +
>> +    # Only support discriminator when base present
>> +    if not (discriminator and base):
>> +        return None
>> +
>> +    base_fields = find_base_fields(base)
>> +
>> +    if not base_fields:
>> +        sys.stderr.write("Base '%s' is not a valid type\n"
>> +                         % base)
>> +        sys.exit(1)
>> +
>> +    descriminator_type = base_fields.get(discriminator)
>
> s/descriminator/discriminator/
>