1 pub(crate) trait Counter: salsa::Database {
increment(&self) -> usize2     fn increment(&self) -> usize;
3 }
4 
5 #[salsa::query_group(GroupStruct)]
6 pub(crate) trait Database: Counter {
memoized(&self) -> usize7     fn memoized(&self) -> usize;
volatile(&self) -> usize8     fn volatile(&self) -> usize;
9 }
10 
11 /// Because this query is memoized, we only increment the counter
12 /// the first time it is invoked.
memoized(db: &dyn Database) -> usize13 fn memoized(db: &dyn Database) -> usize {
14     db.volatile()
15 }
16 
17 /// Because this query is volatile, each time it is invoked,
18 /// we will increment the counter.
volatile(db: &dyn Database) -> usize19 fn volatile(db: &dyn Database) -> usize {
20     db.salsa_runtime().report_untracked_read();
21     db.increment()
22 }
23