Struct BoundedCache 

pub struct BoundedCache<C> { /* private fields */ }

A cache wrapper that caps total memory consumption by byte count.

Memory is tracked as key.len() + value.len() for every live entry. When inserting a new entry would exceed max_bytes, the oldest entries (tracked in insertion order) are evicted until there is enough budget.

Type parameters

• C: an inner Cache<Vec<u8>, Vec<u8>> implementation.

Implementations

impl<C> BoundedCache<C>

where C: Cache<Vec<u8>, Vec<u8>>,

pub fn new(inner: C, max_bytes: usize) -> Self

Create a new BoundedCache wrapping inner with a hard byte budget.

max_bytes is the maximum combined byte size of all keys and values.

pub fn current_bytes(&self) -> usize

Return the current byte usage.

pub fn max_bytes(&self) -> usize

Return the maximum byte budget.

Trait Implementations

impl<C> Cache<Vec<u8>, Vec<u8>> for BoundedCache<C>

where C: Cache<Vec<u8>, Vec<u8>>,

fn get(&mut self, key: &Vec<u8>) -> Option<&Vec<u8>>

Look up key, returning a reference to the value if present.

fn put(&mut self, key: Vec<u8>, value: Vec<u8>) -> Option<Vec<u8>>

Insert or update key -> value without a TTL.

fn put_with_ttl( &mut self, key: Vec<u8>, value: Vec<u8>, ttl: Duration, ) -> Option<Vec<u8>>

Insert or update key -> value with a time-to-live.

fn len(&self) -> usize

Return the number of live entries currently in the cache.

fn cap(&self) -> usize

Return the maximum number of entries the cache can hold.

fn remove(&mut self, key: &Vec<u8>) -> Option<Vec<u8>>

Remove the entry associated with key, returning its value if present.

fn clear(&mut self)

Remove all entries from the cache.

fn peek(&self, key: &Vec<u8>) -> Option<&Vec<u8>>

Look up key without updating access metadata (no promotion).

fn contains_key(&self, key: &Vec<u8>) -> bool

Return true if key is present in the cache (without promotion).

fn resize(&mut self, new_cap: usize)

Dynamically resize the cache capacity.

fn is_empty(&self) -> bool

Return true if the cache holds no entries.

fn get_or_insert(&mut self, key: K, default: impl FnOnce() -> V) -> &V

where K: Clone,

Return &V for key, inserting default() if the key is absent.

fn values(&self) -> Vec<&V>

Return all live (non-expired) values currently stored in the cache.

fn warm(&mut self, iter: impl IntoIterator<Item = (K, V)>)

Pre-populate the cache with (key, value) pairs from an iterator.