nsoperationqueue

Currently I'm using NSThread to cache images in another thread. [NSThread detachNewThreadSelector:@selector(cacheImage:) toTarget:self withObject:image]; Alternately: [self performSelectorInBackground:@selector(cacheImage:) withObject:image]; Alternately, I can use an NSOperationQueue NSInvocationOperation *invOperation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(cacheImage:) object:image]; NSOperationQueue *opQueue = [[NSOperationQueue alloc] init]; [opQueue addOperation:invOperation]; Is there any reason to switch away from NSThread ? GCD is a 4th option when it's

Is it possible to use an NSoperationQueue object as a serial FIFO queue by setting its maxConcurrentOperationCount to 1? I note that the docs state... For a queue whose maximum number of concurrent operations is set to 1, this equates to a serial queue. However, you should never rely on the serial execution of operation objects. Does this mean that FIFO execution is not guaranteed? In most cases, it will be FIFO. However, you can set up dependencies between NSOperations such that an operation submitted early will let other operations pass it by in the queue until its dependencies are satisfied

I'm trying to build a bulk image downloader, where images can be added to a queue on the fly to be downloaded, and I can find out the progress and when they're done downloading. Through my reading it seems like NSOperationQueue for the queue functionality and NSURLSession for the network functionality seems like my best bet, but I'm confused as to how to use the two in tandem. I know I add instances of NSOperation to the NSOperationQueue and they get queued. And it seems I create a download task with NSURLSessionDownloadTask , and multiple if I need multiple tasks, but I'm not sure how I put

Today I've met one weird issue when I was trying to 'generalize' my 'CoreData importing operations'. It appeared that if I create a generic subclass of NSOperation the main() func won't be called. Simple example: class MyOperation<T: NSObject>: NSOperation { override func main() { println("My operation main was called") } } If you create an instance of this class and add it to the operationQueue you will see that it's main() isn't actually called. override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view, typically from a nib. self.operationQueue =

I have a long running loop I want to run in the background with an NSOperation . I'd like to use a block: NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{ while(/* not canceled*/){ //do something... } }]; The question is, how to I check to see if it's canceled. The block doesn't take any arguments, and operation is nil at the time it's captured by the block. Is there no way to cancel block operations? Doh. Dear future googlers: of course operation is nil when copied by the block, but it doesn't have to be copied. It can be qualified with __block like so: //THIS MIGHT