A deep equality comparison for any NSObject

gistfile1.m

- (BOOL)isEqual:(id)object {
    if ( [object isMemberOfClass:self.class] ) {
        unsigned int count;
        Ivar* ivars = class_copyIvarList(self.class, &count);
        for(unsigned int i = 0; i < count; ++i) {
            NSObject* lhs = object_getIvar(self, ivars[i]);
            NSObject* rhs = object_getIvar(object, ivars[i]);
            if ( [lhs isKindOfClass:NSObject.class] && [rhs isKindOfClass:NSObject.class] ) {
                if ( ![lhs isEqual:rhs] ) {
                    free(ivars);
                    return NO;
                }
            } else {
                free(ivars);
                return NO;
            }
        }
        free(ivars);
        return YES;
    }
    return NO;
}