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#![cfg_attr(feature = "nightly", feature(drain))]
#![deny(missing_docs)]
#![cfg_attr(test, deny(dead_code))]
#![cfg_attr(not(test), allow(dead_code))]
use std::thread;
#[cfg(not(feature = "nightly"))] use std::mem;
pub struct Spawner {
threads: Vec<thread::JoinHandle<()>>
}
impl Spawner {
pub fn new() -> Spawner { Spawner { threads: vec![] } }
pub fn spawn_collected<F>(&mut self, f: F)
where F: FnOnce(), F: Send + 'static
{
self.threads.push(thread::spawn(f));
}
pub fn spawn<F, T>(&mut self, f: F) -> thread::JoinHandle<T>
where F: FnOnce() -> T, F: Send + 'static, T: Send + 'static
{
thread::spawn(f)
}
}
impl Drop for Spawner {
#[cfg(feature = "nightly")]
fn drop(&mut self) {
assert!(self.threads.drain(..)
.map(thread::JoinHandle::join)
.find(Result::is_err)
.is_none());
}
#[cfg(not(feature = "nightly"))]
fn drop(&mut self) {
assert!(mem::replace(&mut self.threads, vec![])
.into_iter()
.map(thread::JoinHandle::join)
.find(Result::is_err)
.is_none());
}
}
#[cfg(test)] mod tests {
use super::Spawner;
#[test]
fn spawn_some_threads() {
use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
use std::thread::sleep;
use std::time::Duration;
static ACTIVE: AtomicUsize = ATOMIC_USIZE_INIT;
{
let mut spawner = Spawner::new();
assert!(
spawner.spawn(move || {
ACTIVE.fetch_add(1, Ordering::SeqCst);
sleep(Duration::from_millis(100));
ACTIVE.fetch_sub(1, Ordering::SeqCst);
})
.join()
.is_ok()
);
assert_eq!(
ACTIVE.load(Ordering::SeqCst),
0
);
for _ in 1..10 {
spawner.spawn_collected(move || {
ACTIVE.fetch_add(1, Ordering::SeqCst);
sleep(Duration::from_millis(100));
ACTIVE.fetch_sub(1, Ordering::SeqCst);
});
}
}
assert_eq!(
ACTIVE.load(Ordering::SeqCst),
0
);
}
#[test]
#[should_panic]
fn failing_thread() {
{
let mut spawner = Spawner::new();
spawner.spawn_collected(move || panic!());
}
}
}