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gearsco.de
1use std::sync::{
2 Arc,
3 atomic::{AtomicU64, Ordering},
4};
5
6/// A generator of unique ids. Only one should be used per compilation run to
7/// ensure ids do not get reused.
8#[derive(Debug, Clone, Default)]
9pub struct UniqueIdGenerator {
10 id: Arc<AtomicU64>,
11}
12
13impl UniqueIdGenerator {
14 pub fn new() -> Self {
15 Self::default()
16 }
17
18 pub fn next(&self) -> u64 {
19 self.id.fetch_add(1, Ordering::Relaxed)
20 }
21}
22
23#[test]
24fn id_geneation() {
25 let ids = UniqueIdGenerator::new();
26 let ids2 = ids.clone();
27
28 assert_eq!(ids.next(), 0);
29 assert_eq!(ids.next(), 1);
30 assert_eq!(ids.next(), 2);
31
32 // Cloned ones use the same counter
33 assert_eq!(ids2.next(), 3);
34 assert_eq!(ids2.next(), 4);
35 assert_eq!(ids2.next(), 5);
36
37 // The original is updated
38 assert_eq!(ids.next(), 6);
39 assert_eq!(ids.next(), 7);
40}