Threadsafe Mutable Dictionary

gistfile1.m

@interface JRMutableDictionary : NSMutableDictionary
@end

@implementation JRMutableDictionary {
    dispatch_queue_t queue;
    NSMutableDictionary *storage;
}

- (void)dealloc {
    if(queue) {
        dispatch_release(queue);
        queue = NULL;
    }
}

- (id)initWithObjects:(NSArray *)objects forKeys:(NSArray *)keys {
    self = [super init];
    if(self) {
        queue = dispatch_queue_create("JRMutableDictionaryDispatchQueue", DISPATCH_QUEUE_CONCURRENT);
        storage = [[NSMutableDictionary alloc] initWithObjects:objects forKeys:keys];
    }
    return self;
}

#pragma mark - NSDictionary

- (NSUInteger)count {
    __block NSUInteger cnt = 0;
    dispatch_sync(queue, ^{
        cnt = [storage count];
    });
    return cnt;
}

- (NSEnumerator *)keyEnumerator {
    __block NSEnumerator *enumerator = nil;
    dispatch_sync(queue, ^{
        enumerator = [storage keyEnumerator];
    });
    return enumerator;
}

- (id)objectForKey:(id)aKey {
    __block id object = nil;
    dispatch_sync(queue, ^{
        object = [storage objectForKey:aKey];
    });
    return object;
}

#pragma mark - NSMutableDictionary

- (void)setObject:(id)anObject forKey:(id)aKey {
    dispatch_barrier_async(queue, ^{
        [storage setObject:anObject forKey:aKey];
    });
}

- (void)removeObjectForKey:(id)aKey {
    dispatch_barrier_async(queue, ^{
        [storage removeObjectForKey:aKey];
    });
}

@end