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
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
use crate::krse::sync::semaphore_ll as ll;
use crate::krse::future::poll_fn;
#[derive(Debug)]
pub struct Semaphore {
ll_sem: ll::Semaphore,
}
#[must_use]
#[derive(Debug)]
pub struct SemaphorePermit<'a> {
sem: &'a Semaphore,
ll_permit: ll::Permit,
}
#[derive(Debug)]
pub struct TryAcquireError(());
impl Semaphore {
pub fn new(permits: usize) -> Self {
Self {
ll_sem: ll::Semaphore::new(permits),
}
}
pub fn available_permits(&self) -> usize {
self.ll_sem.available_permits()
}
pub fn add_permits(&self, n: usize) {
self.ll_sem.add_permits(n);
}
pub async fn acquire(&self) -> SemaphorePermit<'_> {
let mut permit = SemaphorePermit {
sem: &self,
ll_permit: ll::Permit::new(),
};
poll_fn(|cx| permit.ll_permit.poll_acquire(cx, &self.ll_sem)).await.unwrap();
permit
}
pub fn try_acquire(&self) -> Result<SemaphorePermit<'_>, TryAcquireError> {
let mut ll_permit = ll::Permit::new();
match ll_permit.try_acquire(&self.ll_sem) {
Ok(_) => Ok(SemaphorePermit { sem: self, ll_permit }),
Err(_) => Err(TryAcquireError(())),
}
}
}
impl<'a> SemaphorePermit<'a> {
pub fn forget(mut self) {
self.ll_permit.forget();
}
}
impl<'a> Drop for SemaphorePermit<'_> {
fn drop(&mut self) {
self.ll_permit.release(&self.sem.ll_sem);
}
}