fn test_raw_entry()

in sgx_tstd/hashbrown/src/map.rs [6138:6236]
84 lines of code
2 McCabe index (conditional complexity)

    fn test_raw_entry() {
        use super::RawEntryMut::{Occupied, Vacant};

        let xs = [(1_i32, 10_i32), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)];

        let mut map: HashMap<_, _> = xs.iter().copied().collect();

        let compute_hash = |map: &HashMap<i32, i32>, k: i32| -> u64 {
            super::make_insert_hash::<i32, _>(map.hasher(), &k)
        };

        // Existing key (insert)
        match map.raw_entry_mut().from_key(&1) {
            Vacant(_) => unreachable!(),
            Occupied(mut view) => {
                assert_eq!(view.get(), &10);
                assert_eq!(view.insert(100), 10);
            }
        }
        let hash1 = compute_hash(&map, 1);
        assert_eq!(map.raw_entry().from_key(&1).unwrap(), (&1, &100));
        assert_eq!(
            map.raw_entry().from_hash(hash1, |k| *k == 1).unwrap(),
            (&1, &100)
        );
        assert_eq!(
            map.raw_entry().from_key_hashed_nocheck(hash1, &1).unwrap(),
            (&1, &100)
        );
        assert_eq!(map.len(), 6);

        // Existing key (update)
        match map.raw_entry_mut().from_key(&2) {
            Vacant(_) => unreachable!(),
            Occupied(mut view) => {
                let v = view.get_mut();
                let new_v = (*v) * 10;
                *v = new_v;
            }
        }
        let hash2 = compute_hash(&map, 2);
        assert_eq!(map.raw_entry().from_key(&2).unwrap(), (&2, &200));
        assert_eq!(
            map.raw_entry().from_hash(hash2, |k| *k == 2).unwrap(),
            (&2, &200)
        );
        assert_eq!(
            map.raw_entry().from_key_hashed_nocheck(hash2, &2).unwrap(),
            (&2, &200)
        );
        assert_eq!(map.len(), 6);

        // Existing key (take)
        let hash3 = compute_hash(&map, 3);
        match map.raw_entry_mut().from_key_hashed_nocheck(hash3, &3) {
            Vacant(_) => unreachable!(),
            Occupied(view) => {
                assert_eq!(view.remove_entry(), (3, 30));
            }
        }
        assert_eq!(map.raw_entry().from_key(&3), None);
        assert_eq!(map.raw_entry().from_hash(hash3, |k| *k == 3), None);
        assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash3, &3), None);
        assert_eq!(map.len(), 5);

        // Nonexistent key (insert)
        match map.raw_entry_mut().from_key(&10) {
            Occupied(_) => unreachable!(),
            Vacant(view) => {
                assert_eq!(view.insert(10, 1000), (&mut 10, &mut 1000));
            }
        }
        assert_eq!(map.raw_entry().from_key(&10).unwrap(), (&10, &1000));
        assert_eq!(map.len(), 6);

        // Ensure all lookup methods produce equivalent results.
        for k in 0..12 {
            let hash = compute_hash(&map, k);
            let v = map.get(&k).copied();
            let kv = v.as_ref().map(|v| (&k, v));

            assert_eq!(map.raw_entry().from_key(&k), kv);
            assert_eq!(map.raw_entry().from_hash(hash, |q| *q == k), kv);
            assert_eq!(map.raw_entry().from_key_hashed_nocheck(hash, &k), kv);

            match map.raw_entry_mut().from_key(&k) {
                Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
                Vacant(_) => assert_eq!(v, None),
            }
            match map.raw_entry_mut().from_key_hashed_nocheck(hash, &k) {
                Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
                Vacant(_) => assert_eq!(v, None),
            }
            match map.raw_entry_mut().from_hash(hash, |q| *q == k) {
                Occupied(mut o) => assert_eq!(Some(o.get_key_value()), kv),
                Vacant(_) => assert_eq!(v, None),
            }
        }
    }