Re: [Qemu-devel] [PATCH v2 2/2] full introspection support for QMP

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

Hi, Amos

> (resend without big attachment)
>
> Hello Eric, other
>
> We had "command, enumeration, type, unionobj" in Eric suggested DataObject
> union, it's helpful for us to provide meaningful metadata in the output.
> but there still exists some problem.
>
> We should describe some arbitrary data struct, I would like to call it "undefined struct"
>
   If user have defined an arbitrary or embbed data struct, I think it
is better leave as it is, instead of generate a new struct for it.
Since qapi-visit.c and qapi-types.c doesn't have a "undefined" struct
for it now, it is a bit risk to do it only in QMP introspection. Maybe
leave it now, and support it when we found it is really useful?(and add
it in qapi-visit.c and qapi-types.c correspondly)


> eg 1:
>    { 'type': 'VersionInfo',
>      'data': {'qemu': {'major': 'int', 'minor': 'int', 'micro': 'int'},
>               'package': 'str'} }
>    it's same as:
>    { 'type': 'newtype',
>      'data': {'major': 'int', 'minor': 'int', 'micro': 'int'} }
>    { 'type': 'VersionInfo',
>      'data': { 'qemu': 'newtype', 'package': 'str'} }
>
>    The difference between original 'DataObjectType' and 'DataObjectUndefinedStruct'
>    is that we don't have 'name' for the DataObject union for undefined struct.
>    so I set the 'name' item in DataObjectBase to be optional.
>
> eg 2:
>    { 'command': 'human-monitor-command',
>    'data': {'command-line': 'str', '*cpu-index': 'int'},
>    'returns': 'str' }
>    ... 'returns': ['RxFilterInfo'] }
>    ... 'returns': 'ChardevReturn' }
>
>    We returns str (native type), list or extended dict here. Sometimes we
>    returns a defined type, but it doesn't need to be extended. And we need
>    to describe this kind of data (type str, dict or list) by "DataObject"
>    in schema definition of DataObject** type.
>
>    So I added a "'reference-type': 'String'" in DataObject union.
>    list, dict will still be described by "DataObjectType"
>
  I guess you want to tip what type may be returned? It seems a bit too
agressive, since the qapi-schema.json didn't tip that those types may
be returned.


>
> You can find the draft patches here:
>    https://github.com/kongove/qemu/commits/qmp-introspection
> I will post the V3 when I finish the cleanup.
>
> Thanks, Amos
>
>
> Command output
> ==============
> https://raw.github.com/kongove/misc/master/txt/qmp-introspection.output.txt (1.6M)
>
> Latest schema definition
> ========================
> { 'type': 'DataObjectBase',
>    'data': { '*name': 'str', 'type': 'str' } }
> { 'union': 'DataObjectMemberType',
>    'discriminator': {},
>    'data': { 'reference': 'str',
>              'undefined': 'DataObject',
>              'extend': 'DataObject' } }
> { 'type': 'DataObjectMember',
>    'data': { 'type': 'DataObjectMemberType', '*name': 'str',
>              '*optional': 'bool', '*recursive': 'bool' } }
> { 'type': 'DataObjectCommand',
>    'data': { '*data': [ 'DataObjectMember' ],
>              '*returns': 'DataObject',
>              '*gen': 'bool' } }
> { 'type': 'DataObjectEnumeration',
>    'data': { 'data': [ 'str' ] } }
> { 'type': 'DataObjectType',
>    'data': { 'data': [ 'DataObjectMember' ] } }
> { 'type': 'DataObjectUndefinedStruct',
>    'data': { 'data': [ 'DataObjectMember' ] } }
> { 'type': 'DataObjectUnion',
>    'data': { 'data': [ 'DataObjectMember' ], '*base': 'str',
>              '*discriminator': 'str' } }
> { 'union': 'DataObject',
>    'base': 'DataObjectBase',
>    'discriminator': 'type',
>    'data': {
>      'command': 'DataObjectCommand',
>      'enumeration': 'DataObjectEnumeration',
>      'type': 'DataObjectType',
>      'undefined-struct': 'DataObjectUndefinedStruct',
>      'reference-type': 'String',
>      'unionobj': 'DataObjectUnion' } }
> { 'command': 'query-qmp-schema', 'returns': ['DataObject'] }
>