address review: stop matching database records once a computed criterion exhausts the work budget

crates/calc/src/eval.rs

@@ -224,6 +224,9 @@ impl Ctx for FnCtx<'_, '_> {
         self.ev.active_criteria = active;
         Some(v)
     }
+    fn exhausted(&self) -> bool {
+        self.ev.exhausted
+    }
     fn has_lambda(&self) -> bool {
         self.lambda.is_some()
     }

crates/functions/src/database.rs

@@ -94,12 +94,14 @@ fn matching_records(db: &Array, crit: &Array, ctx: &mut dyn Ctx) -> Vec<usize> {
         .filter(|&rec| {
             all_match
                 || rows.iter().any(|(r, conds)| {
-                    conds.iter().all(|(c, col, cr)| match col {
-                        Some(f) => cr.matches(db.get(rec, *f).unwrap_or(&Value::Empty)),
-                        // Under a label that names no field, only a formula (a computed
-                        // criterion) can hold.
-                        None => ctx.computed_criterion(*r, *c, db, rec).unwrap_or(false),
-                    })
+                    // Out of work: a computed criterion would fail at once, so records are left out cheaply.
+                    !ctx.exhausted()
+                        && conds.iter().all(|(c, col, cr)| match col {
+                            Some(f) => cr.matches(db.get(rec, *f).unwrap_or(&Value::Empty)),
+                            // Under a label that names no field, only a formula (a computed
+                            // criterion) can hold.
+                            None => ctx.computed_criterion(*r, *c, db, rec).unwrap_or(false),
+                        })
                 })
         })
         .collect()
@@ -352,6 +354,37 @@ mod tests {
         is_err(d("DSUM", n(9.0)), CellError::Value);
     }
 
+    /// Computed criteria are no longer asked for once the host is out of work.
+    #[test]
+    fn matching_stops_asking_computed_criteria_when_exhausted() {
+        struct Spent {
+            asked: usize,
+        }
+        impl crate::Ctx for Spent {
+            fn date_system(&self) -> gridcraft_core::DateSystem {
+                gridcraft_core::DateSystem::D1900
+            }
+            fn now_serial(&self) -> f64 {
+                0.0
+            }
+            fn random(&mut self) -> f64 {
+                0.0
+            }
+            fn computed_criterion(&mut self, _: usize, _: usize, _: &gridcraft_core::Array, _: usize) -> Option<bool> {
+                self.asked += 1;
+                Some(true)
+            }
+            fn exhausted(&self) -> bool {
+                self.asked > 0
+            }
+        }
+        let criteria = arr(vec![vec![tv("Formula")], vec![nv(1.0)]]);
+        let mut ctx = Spent { asked: 0 };
+        let spec = crate::lookup("DCOUNT").unwrap();
+        crate::call(spec, &[rf(db()), t("Age"), rf(criteria)], &mut ctx);
+        assert_eq!(ctx.asked, 1);
+    }
+
     #[test]
     fn simple_criteria() {
         let c = |cells: Vec<Value>| arr(vec![vec![tv("Tree"), tv("Height")], cells]);

crates/functions/src/lib.rs

@@ -113,6 +113,11 @@ pub trait Ctx {
     fn computed_criterion(&mut self, _row: usize, _col: usize, _db: &Array, _record: usize) -> Option<bool> {
         None
     }
+    /// Whether the cell's work budget has run out: the database functions stop asking for computed
+    /// criteria then, as every one would fail at once.
+    fn exhausted(&self) -> bool {
+        false
+    }
     /// For GROUPBY/PIVOTBY: whether their function argument is a LAMBDA (its value is then not used).
     fn has_lambda(&self) -> bool {
         false