ordermap 0.5.10

use super::{Entry, Equivalent, IndexedEntry, IterMut2, OccupiedEntry, OrderMap, VacantEntry};
use core::hash::{BuildHasher, Hash};
use indexmap::map::MutableEntryKey as _;
use indexmap::map::MutableKeys as _;

/// Opt-in mutable access to [`OrderMap`] keys.
///
/// These methods expose `&mut K`, mutable references to the key as it is stored
/// in the map.
/// You are allowed to modify the keys in the map **if the modification
/// does not change the key's hash and equality**.
///
/// If keys are modified erroneously, you can no longer look them up.
/// This is sound (memory safe) but a logical error hazard (just like
/// implementing `PartialEq`, `Eq`, or `Hash` incorrectly would be).
///
/// `use` this trait to enable its methods for `OrderMap`.
///
/// This trait is sealed and cannot be implemented for types outside this crate.
pub trait MutableKeys: private::Sealed {
    type Key;
    type Value;

    /// Return item index, mutable reference to key and value
    ///
    /// Computes in **O(1)** time (average).
    fn get_full_mut2<Q>(&mut self, key: &Q) -> Option<(usize, &mut Self::Key, &mut Self::Value)>
    where
        Q: ?Sized + Hash + Equivalent<Self::Key>;

    /// Return mutable reference to key and value at an index.
    ///
    /// Valid indices are `0 <= index < self.len()`.
    ///
    /// Computes in **O(1)** time.
    fn get_index_mut2(&mut self, index: usize) -> Option<(&mut Self::Key, &mut Self::Value)>;

    /// Return an iterator over the key-value pairs of the map, in their order
    fn iter_mut2(&mut self) -> IterMut2<'_, Self::Key, Self::Value>;

    /// Scan through each key-value pair in the map and keep those where the
    /// closure `keep` returns `true`.
    ///
    /// The elements are visited in order, and remaining elements keep their
    /// order.
    ///
    /// Computes in **O(n)** time (average).
    fn retain2<F>(&mut self, keep: F)
    where
        F: FnMut(&mut Self::Key, &mut Self::Value) -> bool;
}

/// Opt-in mutable access to [`OrderMap`] keys.
///
/// See [`MutableKeys`] for more information.
impl<K, V, S> MutableKeys for OrderMap<K, V, S>
where
    S: BuildHasher,
{
    type Key = K;
    type Value = V;

    fn get_full_mut2<Q>(&mut self, key: &Q) -> Option<(usize, &mut K, &mut V)>
    where
        Q: ?Sized + Hash + Equivalent<K>,
    {
        self.inner.get_full_mut2(key)
    }

    fn get_index_mut2(&mut self, index: usize) -> Option<(&mut K, &mut V)> {
        self.inner.get_index_mut2(index)
    }

    fn iter_mut2(&mut self) -> IterMut2<'_, Self::Key, Self::Value> {
        self.inner.iter_mut2()
    }

    fn retain2<F>(&mut self, keep: F)
    where
        F: FnMut(&mut K, &mut V) -> bool,
    {
        self.inner.retain2(keep);
    }
}

/// Opt-in mutable access to [`Entry`] keys.
///
/// These methods expose `&mut K`, mutable references to the key as it is stored
/// in the map.
/// You are allowed to modify the keys in the map **if the modification
/// does not change the key's hash and equality**.
///
/// If keys are modified erroneously, you can no longer look them up.
/// This is sound (memory safe) but a logical error hazard (just like
/// implementing `PartialEq`, `Eq`, or `Hash` incorrectly would be).
///
/// `use` this trait to enable its methods for `Entry`.
///
/// This trait is sealed and cannot be implemented for types outside this crate.
pub trait MutableEntryKey: private::Sealed {
    type Key;

    /// Gets a mutable reference to the entry's key, either within the map if occupied,
    /// or else the new key that was used to find the entry.
    fn key_mut(&mut self) -> &mut Self::Key;
}

/// Opt-in mutable access to [`Entry`] keys.
///
/// See [`MutableEntryKey`] for more information.
impl<K, V> MutableEntryKey for Entry<'_, K, V> {
    type Key = K;
    fn key_mut(&mut self) -> &mut Self::Key {
        match self {
            Entry::Occupied(e) => e.key_mut(),
            Entry::Vacant(e) => e.key_mut(),
        }
    }
}

/// Opt-in mutable access to [`OccupiedEntry`] keys.
///
/// See [`MutableEntryKey`] for more information.
impl<K, V> MutableEntryKey for OccupiedEntry<'_, K, V> {
    type Key = K;
    fn key_mut(&mut self) -> &mut Self::Key {
        self.inner.key_mut()
    }
}

/// Opt-in mutable access to [`VacantEntry`] keys.
///
/// See [`MutableEntryKey`] for more information.
impl<K, V> MutableEntryKey for VacantEntry<'_, K, V> {
    type Key = K;
    fn key_mut(&mut self) -> &mut Self::Key {
        self.inner.key_mut()
    }
}

/// Opt-in mutable access to [`IndexedEntry`] keys.
///
/// See [`MutableEntryKey`] for more information.
impl<K, V> MutableEntryKey for IndexedEntry<'_, K, V> {
    type Key = K;
    fn key_mut(&mut self) -> &mut Self::Key {
        self.inner.key_mut()
    }
}

mod private {
    pub trait Sealed {}

    impl<K, V, S> Sealed for super::OrderMap<K, V, S> {}
    impl<K, V> Sealed for super::Entry<'_, K, V> {}
    impl<K, V> Sealed for super::OccupiedEntry<'_, K, V> {}
    impl<K, V> Sealed for super::VacantEntry<'_, K, V> {}
    impl<K, V> Sealed for super::IndexedEntry<'_, K, V> {}
}