Method add

aiscript-arena/src/dynamic_roots.rs:249–286

(&mut self, p: Gc<'gc, ()>)

    }

    fn add(&mut self, p: Gc<'gc, ()>) -> Index {
        // Occupied slot refcount starts at 0. A refcount of 0 and a set ptr implies that there is
        // *one* live reference.

        if self.next_free != NULL_INDEX {
            let idx = self.next_free;
            let slot = &mut self.slots[idx];
            match *slot {
                Slot::Vacant { next_free } => {
                    self.next_free = next_free;
                }
                Slot::Occupied { .. } => panic!("free slot linked list corrupted"),
            }
            *slot = Slot::Occupied {
                root: p,
                ref_count: 0,
            };
            idx
        } else {
            let idx = self.slots.len();

            let old_capacity = self.slots.capacity();
            self.slots.push(Slot::Occupied {
                root: p,
                ref_count: 0,
            });
            let new_capacity = self.slots.capacity();

            debug_assert!(new_capacity >= old_capacity);
            if new_capacity > old_capacity {
                self.metrics.mark_external_allocation(
                    (new_capacity - old_capacity) * mem::size_of::<Slot>(),
                );
            }

            idx
        }
    }

    fn inc(&mut self, idx: Index) {
        match &mut self.slots[idx] {