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// run-pass
// compile-flags:--test
// ignore-emscripten
use std::sync::mpsc::channel;
use std::sync::mpsc::TryRecvError;
use std::sync::mpsc::RecvError;
use std::sync::mpsc::RecvTimeoutError;
use std::sync::Arc;
use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering;
use std::thread;
use std::time::Duration;
/// Simple thread synchronization utility
struct Barrier {
// Not using mutex/condvar for precision
shared: Arc<AtomicUsize>,
count: usize,
}
impl Barrier {
fn new(count: usize) -> Vec<Barrier> {
let shared = Arc::new(AtomicUsize::new(0));
(0..count).map(|_| Barrier { shared: shared.clone(), count: count }).collect()
}
fn new2() -> (Barrier, Barrier) {
let mut v = Barrier::new(2);
(v.pop().unwrap(), v.pop().unwrap())
}
/// Returns when `count` threads enter `wait`
fn wait(self) {
self.shared.fetch_add(1, Ordering::SeqCst);
while self.shared.load(Ordering::SeqCst) != self.count {
#[cfg(target_env = "sgx")]
thread::yield_now();
}
}
}
fn shared_close_sender_does_not_lose_messages_iter() {
let (tb, rb) = Barrier::new2();
let (tx, rx) = channel();
let _ = tx.clone(); // convert to shared
thread::spawn(move || {
tb.wait();
thread::sleep(Duration::from_micros(1));
tx.send(17).expect("send");
drop(tx);
});
let i = rx.into_iter();
rb.wait();
// Make sure it doesn't return disconnected before returning an element
assert_eq!(vec![17], i.collect::<Vec<_>>());
}
#[test]
fn shared_close_sender_does_not_lose_messages() {
with_minimum_timer_resolution(|| {
for _ in 0..10000 {
shared_close_sender_does_not_lose_messages_iter();
}
});
}
// https://github.com/rust-lang/rust/issues/39364
fn concurrent_recv_timeout_and_upgrade_iter() {
// 1 us
let sleep = Duration::new(0, 1_000);
let (a, b) = Barrier::new2();
let (tx, rx) = channel();
let th = thread::spawn(move || {
a.wait();
loop {
match rx.recv_timeout(sleep) {
Ok(_) => {
break;
},
Err(_) => {},
}
}
});
b.wait();
thread::sleep(sleep);
tx.clone().send(()).expect("send");
th.join().unwrap();
}
#[test]
fn concurrent_recv_timeout_and_upgrade() {
with_minimum_timer_resolution(|| {
for _ in 0..10000 {
concurrent_recv_timeout_and_upgrade_iter();
}
});
}
fn concurrent_writes_iter() {
const THREADS: usize = 4;
const PER_THR: usize = 100;
let mut bs = Barrier::new(THREADS + 1);
let (tx, rx) = channel();
let mut threads = Vec::new();
for j in 0..THREADS {
let tx = tx.clone();
let b = bs.pop().unwrap();
threads.push(thread::spawn(move || {
b.wait();
for i in 0..PER_THR {
tx.send(j * 1000 + i).expect("send");
}
}));
}
let b = bs.pop().unwrap();
b.wait();
let mut v: Vec<_> = rx.iter().take(THREADS * PER_THR).collect();
v.sort();
for j in 0..THREADS {
for i in 0..PER_THR {
assert_eq!(j * 1000 + i, v[j * PER_THR + i]);
}
}
for t in threads {
t.join().unwrap();
}
let one_us = Duration::new(0, 1000);
assert_eq!(TryRecvError::Empty, rx.try_recv().unwrap_err());
assert_eq!(RecvTimeoutError::Timeout, rx.recv_timeout(one_us).unwrap_err());
drop(tx);
assert_eq!(RecvError, rx.recv().unwrap_err());
assert_eq!(RecvTimeoutError::Disconnected, rx.recv_timeout(one_us).unwrap_err());
assert_eq!(TryRecvError::Disconnected, rx.try_recv().unwrap_err());
}
#[test]
fn concurrent_writes() {
with_minimum_timer_resolution(|| {
for _ in 0..100 {
concurrent_writes_iter();
}
});
}
#[cfg(windows)]
pub mod timeapi {
#![allow(non_snake_case)]
use std::ffi::c_uint;
pub const TIMERR_NOERROR: c_uint = 0;
#[link(name = "winmm")]
extern "system" {
pub fn timeBeginPeriod(uPeriod: c_uint) -> c_uint;
pub fn timeEndPeriod(uPeriod: c_uint) -> c_uint;
}
}
/// Window's minimum sleep time can be as much as 16ms.
// This function evaluates the closure with this resolution
// set as low as possible.
///
/// This takes the above test's duration from 10000*16/1000/60=2.67 minutes to ~16 seconds.
fn with_minimum_timer_resolution(f: impl Fn()) {
#[cfg(windows)]
unsafe {
let ret = timeapi::timeBeginPeriod(1);
assert_eq!(ret, timeapi::TIMERR_NOERROR);
f();
let ret = timeapi::timeEndPeriod(1);
assert_eq!(ret, timeapi::TIMERR_NOERROR);
}
#[cfg(not(windows))]
{
f();
}
}
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