salsa/salsa-2022-tests/tests/mutate_in_place.rs
Jack Rickard 5b8464c4f9
Support on-demand inputs
This adds initial support for on-demand inputs by allowing new inputs to
be created with only a shared reference to the database. This allows
creating new inputs during a revision and therefore from inside tracked
functions.
2022-09-15 21:25:53 +01:00

52 lines
1.1 KiB
Rust

//! Test that a setting a field on a `#[salsa::input]`
//! overwrites and returns the old value.
use salsa_2022_tests::{HasLogger, Logger};
use test_log::test;
#[salsa::jar(db = Db)]
struct Jar(MyInput);
trait Db: salsa::DbWithJar<Jar> + HasLogger {}
#[salsa::input(jar = Jar)]
struct MyInput {
field: String,
}
#[salsa::db(Jar)]
#[derive(Default)]
struct Database {
storage: salsa::Storage<Self>,
logger: Logger,
}
impl salsa::Database for Database {}
impl Db for Database {}
impl HasLogger for Database {
fn logger(&self) -> &Logger {
&self.logger
}
}
#[test]
fn execute() {
let mut db = Database::default();
let input = MyInput::new(&db, "Hello".to_string());
// Overwrite field with an empty String
// and store the old value in my_string
let mut my_string = input.set_field(&mut db).to(String::new());
my_string.push_str(" World!");
// Set the field back to out initial String,
// expecting to get the empty one back
assert_eq!(input.set_field(&mut db).to(my_string), "");
// Check if the stored String is the one we expected
assert_eq!(input.field(&db), "Hello World!");
}