cascara 0.1.1

Implementation of TinyLFU cache
Documentation 
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use crate::store::{Item, Store};
use indexmap::map::Keys;
use std::iter::FusedIterator;

pub struct Iter<'a, K, V, S>
where
    S: Store<K, V>,
{
    store: &'a S,
    keys: Keys<'a, u64, Item<K, V>>,
}

impl<'a, K, V, S> Iter<'a, K, V, S>
where
    S: Store<K, V>,
{
    pub fn new(store: &'a S) -> Self {
        let keys = store.keys();
        Self { store, keys }
    }
}

impl<'a, K, V, S> Iterator for Iter<'a, K, V, S>
where
    S: Store<K, V>,
{
    type Item = (&'a K, &'a V);

    fn next(&mut self) -> Option<Self::Item> {
        if let Some(k) = self.keys.next() {
            if let Some(item) = self.store.get(k) {
                Some((&item.k, &item.v))
            } else {
                unreachable!()
            }
        } else {
            None
        }
    }
}

impl<'a, K, V, S> FusedIterator for Iter<'a, K, V, S> where S: Store<K, V> {}

#[cfg(test)]
mod tests {
    use crate::Cache;

    #[test]
    fn iter() {
        let mut cache = Cache::<u8, u8>::new(10);
        assert!(cache.insert(1, 1).is_ok());
        assert!(cache.insert(2, 2).is_ok());
        assert!(cache.insert(3, 3).is_ok());
        let items = cache.iter().collect::<Vec<(&u8, &u8)>>();
        assert_eq!(items, vec![(&1, &1), (&2, &2), (&3, &3)])
    }
}