salsa/tests/accumulate-from-tracked-fn.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

73 lines
1.7 KiB
Rust

//! Accumulate values from within a tracked function.
//! Then mutate the values so that the tracked function re-executes.
//! Check that we accumulate the appropriate, new values.
use expect_test::expect;
use salsa::{Accumulator, Setter};
use test_log::test;
#[salsa::input]
struct List {
value: u32,
next: Option<List>,
}
#[salsa::accumulator]
#[derive(Copy)]
struct Integers(u32);
#[salsa::tracked]
fn compute(db: &dyn salsa::Database, input: List) {
eprintln!(
"{:?}(value={:?}, next={:?})",
input,
input.value(db),
input.next(db)
);
let result = if let Some(next) = input.next(db) {
let next_integers = compute::accumulated::<Integers>(db, next);
eprintln!("{:?}", next_integers);
let v = input.value(db) + next_integers.iter().map(|a| a.0).sum::<u32>();
eprintln!("input={:?} v={:?}", input.value(db), v);
v
} else {
input.value(db)
};
Integers(result).accumulate(db);
eprintln!("pushed result {:?}", result);
}
#[test]
fn test1() {
let mut db = salsa::DatabaseImpl::new();
let l0 = List::new(&db, 1, None);
let l1 = List::new(&db, 10, Some(l0));
compute(&db, l1);
expect![[r#"
[
Integers(
11,
),
Integers(
1,
),
]
"#]]
.assert_debug_eq(&compute::accumulated::<Integers>(&db, l1));
l0.set_value(&mut db).to(2);
compute(&db, l1);
expect![[r#"
[
Integers(
12,
),
Integers(
2,
),
]
"#]]
.assert_debug_eq(&compute::accumulated::<Integers>(&db, l1));
}