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
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
use crate::sync::semaphore_ll::*;
use futures::future::poll_fn;
use loom::future::block_on;
use loom::thread;
use std::future::Future;
use std::pin::Pin;
use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering::SeqCst;
use std::sync::Arc;
use std::task::Poll::Ready;
use std::task::{Context, Poll};
#[test]
fn basic_usage() {
const NUM: usize = 2;
struct Actor {
waiter: Permit,
shared: Arc<Shared>,
}
struct Shared {
semaphore: Semaphore,
active: AtomicUsize,
}
impl Future for Actor {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
let me = &mut *self;
ready!(me.waiter.poll_acquire(cx, &me.shared.semaphore)).unwrap();
let actual = me.shared.active.fetch_add(1, SeqCst);
assert!(actual <= NUM - 1);
let actual = me.shared.active.fetch_sub(1, SeqCst);
assert!(actual <= NUM);
me.waiter.release(&me.shared.semaphore);
Ready(())
}
}
loom::model(|| {
let shared = Arc::new(Shared {
semaphore: Semaphore::new(NUM),
active: AtomicUsize::new(0),
});
for _ in 0..NUM {
let shared = shared.clone();
thread::spawn(move || {
block_on(Actor {
waiter: Permit::new(),
shared,
});
});
}
block_on(Actor {
waiter: Permit::new(),
shared,
});
});
}
#[test]
fn release() {
loom::model(|| {
let semaphore = Arc::new(Semaphore::new(1));
{
let semaphore = semaphore.clone();
thread::spawn(move || {
let mut permit = Permit::new();
block_on(poll_fn(|cx| permit.poll_acquire(cx, &semaphore))).unwrap();
permit.release(&semaphore);
});
}
let mut permit = Permit::new();
block_on(poll_fn(|cx| permit.poll_acquire(cx, &semaphore))).unwrap();
permit.release(&semaphore);
});
}
#[test]
fn basic_closing() {
const NUM: usize = 2;
loom::model(|| {
let semaphore = Arc::new(Semaphore::new(1));
for _ in 0..NUM {
let semaphore = semaphore.clone();
thread::spawn(move || {
let mut permit = Permit::new();
for _ in 0..2 {
block_on(poll_fn(|cx| {
permit.poll_acquire(cx, &semaphore).map_err(|_| ())
}))?;
permit.release(&semaphore);
}
Ok::<(), ()>(())
});
}
semaphore.close();
});
}
#[test]
fn concurrent_close() {
const NUM: usize = 3;
loom::model(|| {
let semaphore = Arc::new(Semaphore::new(1));
for _ in 0..NUM {
let semaphore = semaphore.clone();
thread::spawn(move || {
let mut permit = Permit::new();
block_on(poll_fn(|cx| {
permit.poll_acquire(cx, &semaphore).map_err(|_| ())
}))?;
permit.release(&semaphore);
semaphore.close();
Ok::<(), ()>(())
});
}
});
}
|
