rust/crates/salsa/tests/parallel/frozen.rs

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2024-02-07 09:29:46 -06:00
use crate::setup::{ParDatabase, ParDatabaseImpl};
use crate::signal::Signal;
use salsa::{Database, ParallelDatabase};
use std::{
panic::{catch_unwind, AssertUnwindSafe},
sync::Arc,
};
/// Add test where a call to `sum` is cancelled by a simultaneous
/// write. Check that we recompute the result in next revision, even
/// though none of the inputs have changed.
#[test]
fn in_par_get_set_cancellation() {
let mut db = ParDatabaseImpl::default();
db.set_input('a', 1);
let signal = Arc::new(Signal::default());
let thread1 = std::thread::spawn({
let db = db.snapshot();
let signal = signal.clone();
move || {
// Check that cancellation flag is not yet set, because
// `set` cannot have been called yet.
catch_unwind(AssertUnwindSafe(|| db.unwind_if_cancelled())).unwrap();
// Signal other thread to proceed.
signal.signal(1);
// Wait for other thread to signal cancellation
catch_unwind(AssertUnwindSafe(|| loop {
db.unwind_if_cancelled();
std::thread::yield_now();
}))
.unwrap_err();
}
});
let thread2 = std::thread::spawn({
move || {
// Wait until thread 1 has asserted that they are not cancelled
// before we invoke `set.`
signal.wait_for(1);
// This will block until thread1 drops the revision lock.
db.set_input('a', 2);
db.input('a')
}
});
thread1.join().unwrap();
let c = thread2.join().unwrap();
assert_eq!(c, 2);
}