Am 02.07.2013 um 19:06 hat Anthony Liguori geschrieben: > Eric Blake <ebl...@redhat.com> writes: > > On 07/02/2013 08:51 AM, Anthony Liguori wrote: > >> Amos Kong <ak...@redhat.com> writes: > >> > >>> Introduces new monitor command to query QMP schema information, > >>> the return data is a nested dict/list, it contains the useful > >>> metadata. > >>> > >>> we can add events definations to qapi-schema.json, then it can > >>> also be queried. > >>> > >>> Signed-off-by: Amos Kong <ak...@redhat.com> > >> > >> Maybe I'm being too meta here, but why not just return qapi-schema.json > >> as a string and call it as day?
I know you don't agree with this, but as I mentioned several times before, I think the schema as returned by the introspection functions shouldn't contain what a qemu of this version _could_ in theory provide, but what this specific build actually _does_ provide. It shouldn't include things that are compiled out. > > I've also been the one arguing that the additional complexity (an array of > > {"name":"str","type":"str","optional":bool"}) is better for libvirt in > > that the JSON is then well-suited for scanning (it is easier to scan > > through an array where the key is a constant "name", and looking for the > > value that we are interested in, than it is to scan through a dictionary > > where the keys of the dictionary are the names we are interested in). > > That is, the JSON in qapi-schema.json is a nice compact representation > > that works for humans, but may be a bit TOO compact for handling via > > machines. > > But adding a bunch of code to do JSON translation just adds a bunch of > additional complexity. > > One reasonable compromise would be: > > { "command": "foo", "arguments": { "name": "str", "id": "int" }, > "optional": { "bar": "bool" } } This assumes that optional vs. mandatory is the only property we ever want to describe for fields. Eric's approach is much more future-proof. Let's keep the format of qapi-schema.json an implementation detail that we can change and extend when necessary. Kevin