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|
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, 1, &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(1, &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, 1, &semaphore))).unwrap();
permit.release(1, &semaphore);
});
}
let mut permit = Permit::new();
block_on(poll_fn(|cx| permit.poll_acquire(cx, 1, &semaphore))).unwrap();
permit.release(1, &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, 1, &semaphore).map_err(|_| ())
}))?;
permit.release(1, &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, 1, &semaphore).map_err(|_| ())
}))?;
permit.release(1, &semaphore);
semaphore.close();
Ok::<(), ()>(())
});
}
});
}
#[test]
fn batch() {
let mut b = loom::model::Builder::new();
b.preemption_bound = Some(1);
b.check(|| {
let semaphore = Arc::new(Semaphore::new(10));
let active = Arc::new(AtomicUsize::new(0));
let mut ths = vec![];
for _ in 0..2 {
let semaphore = semaphore.clone();
let active = active.clone();
ths.push(thread::spawn(move || {
let mut permit = Permit::new();
for n in &[4, 10, 8] {
block_on(poll_fn(|cx| permit.poll_acquire(cx, *n, &semaphore))).unwrap();
active.fetch_add(*n as usize, SeqCst);
let num_active = active.load(SeqCst);
assert!(num_active <= 10);
thread::yield_now();
active.fetch_sub(*n as usize, SeqCst);
permit.release(*n, &semaphore);
}
}));
}
for th in ths.into_iter() {
th.join().unwrap();
}
assert_eq!(10, semaphore.available_permits());
});
}
|
