Weak, Strong, Unowned - Hector Matos

Transcript

1. Weak, Strong, Unowned Oh, My!
2. Quick Intro
3. Hi! I'm Hector Matos
5. Sr. Software Engineer @ Capital One
6. @allonsykraken on the Twitters
7. Father of KrakenDev.io
8. ARC
9. - (void)releaseTheKraken { Kraken *kraken = [[Kraken alloc] init]; //+1 retain [kraken release]; //generated by ARC }
10. Magic has it's limitations And so does ARC
11. Leaked Memory & Retain Cycles
14. Strong References Default in Swift
15. Now Stop, Example Time //Kraken holds a strong reference to the yummy human. class Kraken { var yummyHuman: Human }
16. // The animation closure holds a strong reference to self // self.retainCount is 1 here UIView.animateWithDuration(0.3) { // self.retainCount is 2 here self.view.alpha = 0.0 }
17. Questions?
18. Weak References Safe - Independent
19. Stop, Collaborate, & Listen! (to my next example) class KrakensFace: UIView { @IBOutlet weak var razorSharpTeeth: UIView! } KrakenAPI.eat(yummyHuman, whenFinished: { [weak self] in self?.waitForNextMealTime() })
20. WTF is "[weak self] in"?!
21. Capture Lists It's just an array. That's all it is. There, there. It's all over now. !
22. KrakenAPI.eat(yummyHuman, finished: { [weak self, unowned lovedOne = yummyHuman.lovedOne] in self?.waitForNextMealTime() })
23. Questions?
24. Unowned References Mutual Dependence
25. class Human { var heart: ! func seeKrakenComing() { heart.haveHeartAttack() } } class !: Organ { unowned let human: Human init(human: Human) { self.human = human } func haveHeartAttack() { human.die() } } let human = Human() human.heart = !(human: human)
26. Questions?
28. ❤