dispatch.swift

import Foundation

class dispatch
{
    class async
    {
        class func bg(block: dispatch_block_t) {
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), block)
        }
        
        class func main(block: dispatch_block_t) {
            dispatch_async(dispatch_get_main_queue(), block)
        }
    }
    
    class sync
    {
        class func bg(block: dispatch_block_t) {
            dispatch_sync(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), block)
        }
        
        class func main(block: dispatch_block_t) {
            if NSThread.isMainThread()  {
                block()
            }
            else {
                dispatch_sync(dispatch_get_main_queue(), block)
            }
        }
    }
    
    class after {
        class func bg(when: dispatch_time_t, block: dispatch_block_t) {
            dispatch_after(when, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)!, block)
        }
        
        class func main(when: dispatch_time_t, block: dispatch_block_t) {
            dispatch_after(when, dispatch_get_main_queue(), block)
        }
    }
}

ViewController.swift

import UIKit
import QuartzCore

class ViewController: UIViewController {

    @IBOutlet weak var label: UILabel
    @IBOutlet weak var counter: UILabel

    override func viewDidLoad() {
        super.viewDidLoad()

        dispatch.async.bg {
            var count = 0;
            for index in 0..10000000 {
                dispatch.sync.main {
                    self.counter.text = "\(index)"
                }
            }
        }
        
        dispatch.after.main(2) {
            NSLog("in main after 2 seconds")
        }
    }

    @IBAction func clickety() {
        label.text = NSDate.date().description
    }
}