Re: [libvirt] [GSoC] Design ideas for implementing cleanup attribute

On Fri, 2018-05-25 at 10:04 +0200, Pavel Hrdina wrote: > On Fri, May 25, 2018 at 09:13:51AM +0200, Andrea Bolognani wrote: > > However, I realize it might not be possible to register free > > functions for a native type without having to introduce something > > like > > > > typedef char * virString; > > > > thus causing massive churn. How does GLib deal with that? > > If you would look into GLib documentation you would see that this > design basically copies the one in GLib: Sorry, I should have looked up the documentation and implementation before asking silly questions. Guess the morning coffee hadn't quite kicked in yet :/ > GLib libvirt > > g_autofree VIR_AUTOFREE > g_autoptr VIR_AUTOPTR > g_auto VIR_AUTOCLEAR For what it's worth, I think VIR_AUTOCLEAR is a much better name than g_auto :) > In GLib you are using them like this: > > g_autofree char *string = NULL; > g_autoptr(virDomain) dom = NULL; > g_auto(virDomain) dom = { 0 }; > > So yes it would require to introduce a lot of typedefs for basic types > and that is not worth it. I'm not sure we would need so many typedefs, but there would certainly be a lot of churn involved. Personally, I'm not so sure it wouldn't be worth the effort, but it's definitely something that we can experiment with it at a later time instead of holding up what's already a pretty significant improvement. > In libvirt we would have: > > VIR_AUTOFREE char *string = NULL; > VIR_AUTOPTR(virDomainPtr) dom = NULL; > VIR_AUTOCLEAR(virDomain) dom = { 0 }; > > If you notice the difference, in libvirt we can use virDomainPtr > directly because we have these typedefs, in GLib macro > G_DEFINE_AUTOPTR_CLEANUP_FUNC creates similar typedef. While I'm not a fan of our *Ptr typedefs in general, I guess this time I'm glad we have them because VIR_AUTOPTR() doesn't hide the fact that what you're declaring is a pointer; that is, the macro argument is also exactly the type of the variable.