Fred, Your suggestion is how toll-free bridging is currently implemented. There are no fast-track functions without the ObjC test. As far as I can tell, the overhead isn't that bad.
The only problem is that not every function maps directly to a method, so there might some additional swizzling needed to make some of those functions work correctly with ObjC objects. Another interesting articles on toll-free bridging is: http://cocoadev.com/wiki/BridgingForFunAndProfit On Thu, Mar 14, 2013 at 3:42 AM, Fred Kiefer <fredkie...@gmx.de> wrote: > On 13.03.2013 09:12, Luboš Doležel wrote: >> >> So guys, what do we do? :-) >> >> I'd be unhappy if this topic just faded away... > > > Same here :-) > > We need a solution where Corebase works without base being present. And when > base is there it should fit in as well. > I read through the documentation at > http://developer.apple.com/library/mac/#documentation/CoreFoundation/Conceptual/CFDesignConcepts/Articles/tollFreeBridgedTypes.html > > We have different options: > > - Implementing CoreBase on top of base wont work as Stef Bidi pointed out, > or rather it only would if we put the full CoreBase into base. > > - Replacing the base classes with CoreBase ones, as implemented in your > changes that started this thread, wont work either. As soon as somebody uses > a self implemented NSString subclass that wont be bridgable to CoreBase. > > - We could make all the CoreBase functions tiny wrappers around Objective-C > classes that are independent of base. I think this was the idea I originally > proposed when we started out on CoreBase. That way we would be able to pass > in base objects into CoreBase functions and things still would work. This > would not allow for the special deallocation functions that are possible for > many CoreBase data types and would thereby limit the way CoreBase could be > used. > > - The only way that could work all the time is to add a test in each > CoreBase function, whether the passed in reference is a CF reference or a > real object and dispatch based on that. This is a lot of overhead, but only > then we will have toll free bridging. > > Having decided that I googled once more and found this article: > http://www.mikeash.com/pyblog/friday-qa-2010-01-22-toll-free-bridging-internals.html > > Which just means, I could have saved myself a lot of reasoning, by doing > this first :-) And this article even points to one with more details. I > think this is the way to go. One downside here is that this means we will > need each CoreBase function twice an internal version that contains the > current implementation and an external, that checks the passed in reference > before calling the internal one. And we will need to figure out a way to do > the message send without objc_msgSend() for the old libobjc runtime. > > Fred > > > > _______________________________________________ > Gnustep-dev mailing list > Gnustep-dev@gnu.org > https://lists.gnu.org/mailman/listinfo/gnustep-dev _______________________________________________ Gnustep-dev mailing list Gnustep-dev@gnu.org https://lists.gnu.org/mailman/listinfo/gnustep-dev
