@implementation PullProcessObject
@synthesize delegate;


- (id)init;
{
	if (!(self = [super init])) {
		return nil;
	}

	mPullQueue = dispatch_queue_create(NULL, 0);
	mProcQueue = dispatch_queue_create(NULL, 0);

	return self;
}



- (void)dealloc
{
	dispatch_release(mPullQueue);
	dispatch_release(mProcQueue);
	[super dealloc];
}




- (void)doPull:(dispatch_semaphore_t)prevSem
{
	dispatch_async(mPullQueue, ^{
		id result = [delegate pull];

		if (result) {
			dispatch_semaphore_t sem = dispatch_semaphore_create(0);


			dispatch_async(mProcQueue, ^{
				[delegate process:result];
				dispatch_semaphore_signal(sem);
			});


			dispatch_async(mPullQueue, ^{
				if (prevSem) {
					dispatch_semaphore_wait(prevSem, DISPATCH_TIME_FOREVER);
					dispatch_release(prevSem);
				}

				[self doPull:sem];
			});


		} else {

			if (prevSem) {
				dispatch_semaphore_wait(prevSem, DISPATCH_TIME_FOREVER);
				dispatch_release(prevSem);
			}

			dispatch_async(mProcQueue, ^{
				[delegate done];
			});

		}
	});
}




- (void)start
{
	[self doPull:nil];
}


@end