Enum cache_2q::Entry

pub enum Entry<'a, K: 'a + Eq + Hash, V: 'a, S: 'a + BuildHasher = RandomState> {
    Occupied(OccupiedEntry<'a, K, V, S>),
    Vacant(VacantEntry<'a, K, V, S>),
}

A view into a single entry in a cache, which may either be vacant or occupied.

This enum is constructed from the entry method on Cache.

Variants

Occupied(OccupiedEntry<'a, K, V, S>)

An occupied entry

Vacant(VacantEntry<'a, K, V, S>)

An vacant entry

Implementations

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

pub fn key(&self) -> &K

Returns a reference to this entry's key.

Examples

use cache_2q::Cache;

let mut cache: Cache<&str, u32> = Cache::new(8);
assert_eq!(cache.entry("poneyland").key(), &"poneyland");

pub fn or_insert(self, default: V) -> &'a mut V

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

Examples

use cache_2q::Cache;

let mut cache = Cache::new(8);
{
    let value = cache.entry(0xFF00).or_insert(0);
    assert_eq!(*value, 0);
}

*cache.entry(0xFF00).or_insert(100) += 1;
assert_eq!(*cache.get(&0xFF00).unwrap(), 1);

pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.

Examples

use cache_2q::Cache;

let mut cache: Cache<&'static str, String> = Cache::new(8);
cache.entry("key").or_insert_with(|| "value".to_string());

assert_eq!(cache.get(&"key").unwrap(), &"value".to_string());

pub fn and_modify<F>(self, f: F) -> Self where
    F: FnOnce(&mut V), 

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

Examples

use cache_2q::Cache;

let mut cache = Cache::new(1);
cache.entry("poneyland")
   .and_modify(|e| { *e += 1 })
   .or_insert(42);
assert_eq!(*cache.get("poneyland").unwrap(), 42);

cache.entry("poneyland")
   .and_modify(|e| { *e += 1 })
   .or_insert(42);
assert_eq!(*cache.get("poneyland").unwrap(), 43);

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

pub fn or_default(self) -> &'a mut V

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

Examples

use cache_2q::Cache;

let mut cache = Cache::new(1);
assert_eq!(*cache.entry(1).or_default(), 0u8);
assert_eq!(cache.get(&1), Some(&mut 0))

Trait Implementations

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

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

Formats the value using the given formatter.