Re: [Qemu-devel] [PATCH v13 03/14] qapi: Convert QType into QAPI built-in enum type

[Eric Blake]

On 11/26/2015 07:51 AM, Markus Armbruster wrote:
> Eric Blake <address@hidden> writes:
> 
>> What's more meta than using qapi to define qapi? :)
>>
>> Convert QType into a full-fledged[*] builtin qapi enum type, so
>> that a subsequent patch can then use it as the discriminator
>> type of qapi alternate types.  Fortunately, the judicious use of
>> 'prefix' in the qapi definition avoids churn to the spelling of
>> the enum constants.
>>

>>  #include <stddef.h>
>>  #include <assert.h>
>> +#include "qapi-types.h"
> 
> Needed for QType.  Risk for circular inclusion.  We're currently fine,
> because generated qapi-types.h includes only "qemu/typedefs.h" (visible
> below).  Should we add a comment to qapi-types.py?

How about this:
 @@ -323,6 +319,7 @@ fdef.write(mcgen('''
 ''',
                   prefix=prefix))

+# To avoid circular headers, use only typedefs.h here, not qobject.h
 fdecl.write(mcgen('''
 #include <stdbool.h>
 #include <stdint.h>
-#include "qapi/qmp/qobject.h"
+#include "qemu/typedefs.h"
 '''))

 schema = QAPISchema(input_file)


>>      def visit_enum_type(self, name, info, values, prefix):
>> -        self._fwdecl += gen_enum(name, values, prefix)
>> -        self._fwdefn += gen_enum_lookup(name, values, prefix)
>> +        # Special case for our lone builtin enum type
>> +        # TODO use something cleaner than existence of info
>> +        if not info:
>> +            self._btin += gen_enum(name, values, prefix)
>> +            if do_builtins:
>> +                self.defn += gen_enum_lookup(name, values, prefix)
>> +        else:
>> +            self._fwdecl += gen_enum(name, values, prefix)
>> +            self._fwdefn += gen_enum_lookup(name, values, prefix)
> 
> Odd: gen_enum_lookup() goes into .defn for built-ins, but ._fwdefn for
> user-defineds.  Makes me suspect it ._fwdefn isn't needed anymore.  A
> quick test compile is happy with .defn for both.
> 
> If we want to keep ._fwdefn for some reason, we should use for built-ins
> as well.

We need it for gen_alternate_qtypes().  But that disappears in 4/14, so
I'll add a patch to clean it up.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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