Struct cache_2q::VacantEntry

pub struct VacantEntry<'a, K: 'a + Eq + Hash, V: 'a, S: 'a + BuildHasher = RandomState> { /* fields omitted */ }

A view into a vacant entry in a Cache. It is part of the Entry enum.

Implementations

impl<'a, K: 'a + Eq + Hash, V: 'a, S: 'a + BuildHasher> VacantEntry<'a, K, V, S>

pub fn key(&self) -> &K

Gets a reference to the key that would be used when inserting a value through the VacantEntry.

Examples

use cache_2q::{Cache, Entry};

let mut cache: Cache<&str, u32> = Cache::new(8);

if let Entry::Vacant(v) = cache.entry("poneyland") {
    assert_eq!(v.key(), &"poneyland");
} else {
    panic!("Entry should be vacant");
}

pub fn into_key(self) -> K

Take ownership of the key.

Examples

use cache_2q::{Cache, Entry};

let mut cache: Cache<String, u32> = Cache::new(8);

if let Entry::Vacant(v) = cache.entry("poneyland".into()) {
    assert_eq!(v.into_key(), "poneyland".to_string());
} else {
    panic!("Entry should be vacant");
}

pub fn is_remembered(&self) -> bool

If this vacant entry is remembered

Keys are remembered after they are evicted from the cache. If this entry is remembered, if inserted, it will be insert to a frequent list, instead of the usual recent list

Examples

use cache_2q::{Cache, Entry};

let mut cache: Cache<&str, u32> = Cache::new(1);

if let Entry::Vacant(v) = cache.entry("poneyland") {
    assert!(!v.is_remembered());
} else {
    panic!("Entry should be vacant");
}

cache.insert("poneyland", 0);
cache.insert("other", 1); // Force poneyland out of the cache
if let Entry::Vacant(v) = cache.entry("poneyland") {
    assert!(v.is_remembered());
    v.insert(0);
} else {
    panic!("Entry should be vacant");
}

impl<'a, K: 'a + Eq + Hash, V: 'a, S: 'a + BuildHasher> VacantEntry<'a, K, V, S>

pub fn insert(self, value: V) -> &'a mut V

Sets the value of the entry with the VacantEntry's key, and returns a mutable reference to it.

Examples

use cache_2q::{Cache, Entry};

let mut cache: Cache<&str, u32> = Cache::new(8);

if let Entry::Vacant(o) = cache.entry("poneyland") {
    o.insert(37);
} else {
    panic!("Entry should be vacant");
}
assert_eq!(*cache.get("poneyland").unwrap(), 37);

Trait Implementations

impl<'a, K: 'a + Debug + Eq + Hash, V: 'a + Debug, S: 'a + BuildHasher> Debug for VacantEntry<'a, K, V, S>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.