NSProxy retain / release

[David Chisnall]

Hi,

I was looking at NSProxy's code, and it seems to store its retain count in an 
ivar, rather than using the standard one.  Is there a reason for this?  It 
means that:

- NSProxy uses one word more than it needs to, two more than it needs to in GC 
mode
- -retain and -release on NSProxy subclasses are not thread-safe (they don't 
use atomic ops)
- -retainCount and NSExtraRefCount give different results (contrary to the 
Cocoa behaviour)

David

$ cat proxy.m
#import <Foundation/Foundation.h>

int main(void)
{
        [NSAutoreleasePool new];
        id p = [NSProxy alloc];
        NSLog(@"%d (%d)", (int)[p retainCount], (int)NSExtraRefCount(p));
        [p retain];
        NSLog(@"%d (%d)", (int)[p retainCount], (int)NSExtraRefCount(p));
        NSIncrementExtraRefCount(p);
        NSLog(@"%d (%d)", (int)[p retainCount], (int)NSExtraRefCount(p));
        return 0;
}

# On Cocoa:
$ clang proxy.m -framework Foundation&& ./a.out 
2011-06-30 14:52:45.314 a.out[63606:903] 0x10010ce90
2011-06-30 14:52:45.318 a.out[63606:903] 1 (0)
2011-06-30 14:52:45.318 a.out[63606:903] 2 (1)
2011-06-30 14:52:45.319 a.out[63606:903] 3 (2)

# On GNUstep:
$ clang `gnustep-config --objc-flags` `gnustep-config --base-libs` proxy.m && 
./a.out
2011-06-30 13:53:55.789 a.out[61681] 0x29ec7c28
2011-06-30 13:53:55.792 a.out[61681] 1 (0)
2011-06-30 13:53:55.795 a.out[61681] 2 (0)
2011-06-30 13:53:55.795 a.out[61681] 2 (1)