The ownership in iOS

Transcript

1. The ownership in iOS Mixleap #11 in Osaka
2. @_natpenguin merpay iOS Software Engineer
3. @_natpenguin merpay iOS Software Engineer .filter { $0 == } .map { $0 + } + [ , ✨ ] =
4. What is ownership?
5. It’s a management system for resource
6. It’s abstract word…
7. Ownership system is already used
8. Rust/C++/Swift… Ownership system is already used
9. Why we need ownership system?
11. - Speed
12. - Safety - Speed
13. - Safety - Speed - Concurrency
14. Safety
15. - Access conflict to Data Rust prevents these in compiling
16. - Access conflict to Data Rust prevents these in compiling - Using after releasing resource
17. fn main() { let x = vec![1, 2, 3]; let y = x; println!(“x[0] is {}", x[0]); } This code will be compiling error
18. fn main() { let x = vec![1, 2, 3]; take(x); println!(“x[0] is {}", x[0]); } fn take(v: Vec<i32>) { // do something } This code will be compiling error
19. fn main() { let mut x = &100; let mut y = &mut x; *y += 1; println!(“y is {}", y); } This code will be compiling error
20. It’s a difficult
22. Manifesto https://github.com/apple/swift/blob/master/docs/OwnershipManifesto.md
23. Q. What does swift want by using it?
24. A. Improving performance Q. What does swift want by using it?
25. - Making extra copies at runtime Problem Point
26. - Making extra copies at runtime - Referencing to unique resource Problem Point
27. - Making extra copies at runtime - Referencing to unique resource - Overhead of reference count Problem Point
28. Point - Prevents simultaneously accessing to Data
29. Point - Prevents simultaneously accessing to Data - Give programmers more control
30. Point - Prevents simultaneously accessing to Data - Give programmers more control - Add types that can’t be implicitly copied
31. A1. Supporting a type that can’t copy Q. How does swift improve performance?
32. A1. Supporting a type that can’t copy Q. How does swift improve performance? A2. Law of exclusivity
33. New keywords - shared
34. func ==(left: shared String, right: shared String) -> Bool { ... } shared String isn’t copied
35. What is different with inout?
36. - shared - inout
37. New keywords - shared - moveonly
38. moveonly struct Foo { // some parameters }
39. moveonly extension Foo { // Some extensions }
40. extension Foo { moveonly func bar<U>(_ u: U) }
41. moveonly struct File { let descriptor: Int32 init(filename: String) throws { descriptor = Darwin.open(filename, O_RDONLY) } deinit { _ = Darwin.close(descriptor) } }
42. When we use it? - Performance tuning
43. When we use it? - More memory management - Performance tuning
44. When we use it? - More memory management - Performance tuning - Already know that no needed to copy
45. Thank you so much!