Struct OptionCache 

pub struct OptionCache<K: PartialEq, V> { /* private fields */ }

A simple cache mapping keys to optional computed values.

If a key is present and Some, the cached value is returned. If a key is absent, the computation is run and cached.

Implementations

impl<K: PartialEq, V: Clone> OptionCache<K, V>

pub fn new() -> Self

Create an empty cache.

pub fn get_or_insert_with( &mut self, key: K, compute: impl FnOnce() -> Option<V>, ) -> Option<V>

where K: Clone,

Get or compute a value for key.

If the key is already cached, returns the cached value. Otherwise runs compute and caches the result.

pub fn insert(&mut self, key: K, value: Option<V>)

where K: Clone, V: Clone,

Explicitly insert a value for a key.

pub fn get(&self, key: &K) -> Option<Option<&V>>

Look up a cached value.

pub fn invalidate(&mut self, key: &K)

Invalidate (remove) an entry.

pub fn clear(&mut self)

Clear the entire cache.

pub fn len(&self) -> usize

Number of cached entries.

pub fn is_empty(&self) -> bool

Returns true if the cache is empty.

Trait Implementations

impl<K: Clone + PartialEq, V: Clone> Clone for OptionCache<K, V>

fn clone(&self) -> OptionCache<K, V>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K: Debug + PartialEq, V: Debug> Debug for OptionCache<K, V>

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

Formats the value using the given formatter.

impl<K: Default + PartialEq, V: Default> Default for OptionCache<K, V>

fn default() -> OptionCache<K, V>

Returns the “default value” for a type.