以下代码来自RxSwift
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
import class Foundation.NSLock
final class AtomicInt: NSLock {
fileprivate var value: Int32
public init(_ value: Int32 = 0) {
self.value = value
}
}
@discardableResult
@inline(__always)
func add(_ this: AtomicInt, _ value: Int32) -> Int32 {
this.lock()
let oldValue = this.value
this.value += value
this.unlock()
return oldValue
}
@discardableResult
@inline(__always)
func sub(_ this: AtomicInt, _ value: Int32) -> Int32 {
this.lock()
let oldValue = this.value
this.value -= value
this.unlock()
return oldValue
}
@discardableResult
@inline(__always)
func fetchOr(_ this: AtomicInt, _ mask: Int32) -> Int32 {
this.lock()
let oldValue = this.value
this.value |= mask
this.unlock()
return oldValue
}
@inline(__always)
func load(_ this: AtomicInt) -> Int32 {
this.lock()
let oldValue = this.value
this.unlock()
return oldValue
}
@discardableResult
@inline(__always)
func increment(_ this: AtomicInt) -> Int32 {
return add(this, 1)
}
@discardableResult
@inline(__always)
func decrement(_ this: AtomicInt) -> Int32 {
return sub(this, 1)
}
@inline(__always)
func isFlagSet(_ this: AtomicInt, _ mask: Int32) -> Bool {
return (load(this) & mask) != 0
}