salsa/tests/parallel/parallel_cancellation.rs
Niko Matsakis daaa78056a switch to new database design
Under this design, *all* databases are a
`DatabaseImpl<U>`, where the `U` implements
`UserData` (you can use `()` if there is none).

Code would default to `&dyn salsa::Database` but
if you want to give access to the userdata, you
can define a custom database trait
`MyDatabase: salsa::Databse` so long as you

* annotate `MyDatabase` trait definition of
  impls of `MyDatabase` with `#[salsa::db]`
* implement `MyDatabase` for `DatabaseImpl<U>`
  where `U` is your userdata (this could be a
  blanket impl, if you don't know the precise
  userdata type).

The `tests/common/mod.rs` shows the pattern.
2024-07-28 12:47:50 +00:00

71 lines
1.6 KiB
Rust

//! Test for cycle recover spread across two threads.
//! See `../cycles.rs` for a complete listing of cycle tests,
//! both intra and cross thread.
use salsa::Cancelled;
use salsa::DatabaseImpl;
use salsa::Handle;
use salsa::Setter;
use crate::setup::Knobs;
use crate::setup::KnobsDatabase;
#[salsa::input]
struct MyInput {
field: i32,
}
#[salsa::tracked]
fn a1(db: &dyn KnobsDatabase, input: MyInput) -> MyInput {
db.signal(1);
db.wait_for(2);
dummy(db, input)
}
#[salsa::tracked]
fn dummy(_db: &dyn KnobsDatabase, _input: MyInput) -> MyInput {
panic!("should never get here!")
}
// Cancellation signalling test
//
// The pattern is as follows.
//
// Thread A Thread B
// -------- --------
// a1
// | wait for stage 1
// signal stage 1 set input, triggers cancellation
// wait for stage 2 (blocks) triggering cancellation sends stage 2
// |
// (unblocked)
// dummy
// panics
#[test]
fn execute() {
let mut db = Handle::new(<DatabaseImpl<Knobs>>::default());
db.knobs().signal_on_will_block.store(3);
let input = MyInput::new(&*db, 1);
let thread_a = std::thread::spawn({
let db = db.clone();
move || a1(&*db, input)
});
input.set_field(db.get_mut()).to(2);
// Assert thread A *should* was cancelled
let cancelled = thread_a
.join()
.unwrap_err()
.downcast::<Cancelled>()
.unwrap();
// and inspect the output
expect_test::expect![[r#"
PendingWrite
"#]]
.assert_debug_eq(&cancelled);
}