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
use std::convert::TryInto;
use std::iter::FromIterator;
use crossbeam_queue::SegQueue;
use tokio::sync::Semaphore;
use crate::atomic::Available;
pub struct Queue<T> {
queue: SegQueue<T>,
semaphore: Semaphore,
available: Available,
}
impl<T> Queue<T> {
pub fn new() -> Self {
Self::default()
}
pub async fn pop(&self) -> T {
let txn = self.available.sub();
let permit = self.semaphore.acquire().await;
txn.commit();
let item = self.queue.pop().unwrap();
permit.forget();
item
}
pub fn try_pop(&self) -> Option<T> {
let txn = self.available.sub();
let permit = self.semaphore.try_acquire().ok()?;
let item = self.queue.pop().unwrap();
txn.commit();
permit.forget();
Some(item)
}
pub fn push(&self, item: T) {
self.queue.push(item);
self.semaphore.add_permits(1);
self.available.add();
}
pub fn len(&self) -> usize {
self.queue.len()
}
pub fn available(&self) -> isize {
self.available.get()
}
}
impl<T> Default for Queue<T> {
fn default() -> Self {
Self {
queue: SegQueue::new(),
semaphore: Semaphore::new(0),
available: Available::new(0),
}
}
}
impl<T> FromIterator<T> for Queue<T> {
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
let queue = SegQueue::new();
for item in iter {
queue.push(item);
}
let size = queue.len();
Self {
queue,
semaphore: Semaphore::new(size),
available: Available::new(size.try_into().unwrap()),
}
}
}