Re: NSNotificationCenter's pointer abuse

[David Chisnall]

On 9 May 2013, at 00:52, Richard Frith-Macdonald <address@hidden> wrote:

>> If GSIMap wont let us mix different usages in on file
> 
> That's a big IF...

The extra conditional code appears to be a work around for GSIMap only being 
able to be used once per compilation unit.  I don't know if this is actually 
the case, but I don't think I've ever seen a file that includes GSIMap.h more 
than once per file.

This file also appears to reimplement a lot of things that are implemented 
elsewhere, and contains a lot of optimisation.  It's not clear how much the 
optimisation actually speeds things up (the IMP caching that it does will give 
a small speedup, but actually breaks the semantics of the notification center - 
see the test case I committed yesterday, which passes on OS X but fails on 
GNUstep).  It's also not clear how applicable it is to modern systems.  The 
memory pool, for example, is unlikely to give a noticeable speedup relative to 
a modern malloc() and will increase both memory usage and fragmentation.

I've started doing a naïve implementation of NSNotificationCenter, which I'd 
like to compare to the existing one for memory usage and performance.  If 
anyone has any code that makes heavy use of notifications, please let me know.

David

-- Sent from my Apple II