Am 06.10.2016 um 17:39 hat Daniel P. Berrange geschrieben: > On Thu, Oct 06, 2016 at 05:30:05PM +0200, Kevin Wolf wrote: > > Am 06.10.2016 um 17:18 hat Daniel P. Berrange geschrieben: > > > On Thu, Oct 06, 2016 at 05:10:42PM +0200, Kevin Wolf wrote: > > > > Am 30.09.2016 um 16:45 hat Daniel P. Berrange geschrieben: > > > > > The example is the NetLegacy type which has 3 levels of > > > > > structs. The modern way to represent this in QemuOpts would > > > > > be the dot-separated component approach > > > > > > > > > > -net vlan=1,id=foo,name=bar,opts.type=tap,\ > > > > > opts.data.fd=3,opts.data.script=ifup > > > > > > > > > > The legacy syntax will just be presenting > > > > > > > > > > -net vlan=1,id=foo,name=bar,type=tap,fd=3,script=ifup > > > > > > > > > > So we need to auto-create 3 levels of struct when visiting. > > > > > > > > > > The implementation here will enable visiting in both the > > > > > modern and legacy syntax, compared to OptsVisitor which > > > > > only allows the legacy syntax. > > > > > > > > So you're actually introducing the modern syntax only now? > > > > > > No, the modern syntax is fully implemented by patch 8. > > > > "now" in the sense of "in this series" (because this means that there is > > no external API to preserve yet). > > Well the syntax implemented in patch 8 is designed to > 100% mirror the QAPI schema structure nesting. I don't > think we want to change that behaviour.
I think patch 8 is fine as it is. > If there are certain QAPI schemas structs can still > have freedom to change though, its fine to reconsider > them > > > > > > This patch is about adding hacks for the legacy syntax used > > > by the OptsVisitor. The OptsVisitor didn't interpret struct > > > nesting at all, so everything looked flat - this only works > > > as long as you don't have the same key used in multiple > > > structs at different levels, so is not useful as a general > > > approach - it only works by luck really. > > > > > > > I don't think an "opts.data." prefix makes a lot of sense. I suspect the > > > > schema looks this way only because we didn't have flat unions in 1.2. > > > > > > > > So, considering that it is a purely internally used type not visible in > > > > QMP, would it make sense to change NetLegacy to be a flat union instead, > > > > with NetLegacyOptions as the common base? Then you get the same flat > > > > namespace that we always had and that makes much more sense as an API. > > > > > > Changing that will impact on the QMP data structure, so I don't think > > > we can do that. > > > > I don't see this type used in QMP at all. It's only used for command > > line parsing, and only with the OptsVisitor, so I think we're fine if we > > flatten it now. > > Ok, yes, it seems "NetLegacy" is only used in CLI arg parsing, so we > do have some freedom there. > > This patch was also needed for -numa handling too - again we might have > some flexibility to flatten that. NumaOptions is also unused in QMP, so it's the same thing. If these two are the only options that need the behaviour, I would prefer if we changed the QAPI schema to flatten them, and then we could save ourselves some complexity by dropping this patch. Kevin
