Struct Cache 

pub struct Cache { /* private fields */ }

A thread-safe Least Recently Used (LRU) cache.

This struct wraps an LruCache in a Mutex to allow concurrent access from multiple threads. It maps canonicalised JSON strings to their corresponding database IDs. It also tracks hit and miss statistics.

Implementations

impl Cache

pub fn new(capacity: usize) -> Self

Creates a new Cache with the specified capacity.

Arguments

• capacity - The maximum number of items the cache can hold. Minimum capacity is 1.

pub fn get(&self, key: &str) -> Option<i32>

Retrieves an ID from the cache if it exists.

Arguments

• key - The canonicalised JSON string key.

Returns

Some(i32) if the key exists, None otherwise. Returns None if the cache mutex is poisoned (treated as cache miss).

pub fn put(&self, key: String, value: i32)

Inserts a key-value pair into the cache.

Arguments

• key - The canonicalised JSON string key.
• value - The database ID associated with the key.

If the cache mutex is poisoned, the operation is silently skipped.

pub fn hits(&self) -> u64

Returns the number of cache hits.

Returns

The total number of successful cache lookups.

pub fn misses(&self) -> u64

Returns the number of cache misses.

Returns

The total number of unsuccessful cache lookups.

pub fn hit_rate(&self) -> f64

Returns the cache hit rate as a percentage.

Returns

The hit rate as a float between 0.0 and 100.0. Returns 0.0 if no cache operations have occurred.

pub fn size(&self) -> usize

Returns the current number of items in the cache.

Returns

The number of items currently stored in the cache. Returns 0 if the cache mutex is poisoned.

pub fn capacity(&self) -> usize

Returns the maximum capacity of the cache.

Returns

The maximum number of items the cache can hold.

pub fn evictions(&self) -> u64

Returns the number of cache evictions.

Returns

The total number of items evicted from the cache.