Crate linera_cache 

Caching utilities for the Linera protocol.

Hash-consing and the “one allocation per content” invariant

ValueCache is the canonical home for content-addressed immutable data (also known as hash-consed data) such as Block, Blob, and ConfirmedBlockCertificate. For such types the cache guarantees that at most one allocation exists per distinct content at any time, and all consumers share the same Arc<T>.

The guarantee is implemented by combining two structures:

• A bounded quick_cache (S3-FIFO eviction) for hot-path lookups.
• A lock-free papaya::HashMap<K, Weak<V>> weak index that survives bounded eviction. If the bounded cache evicts an entry while a consumer still holds an Arc, re-requesting the same key returns the existing allocation instead of creating a duplicate.

A background task periodically sweeps dead Weak entries from the index to prevent unbounded growth.

For the invariant to hold, all inserts of hash-consed values must go through the cache (e.g. ValueCache::insert or ValueCache::insert_hashed). The Arc newtype enforces this structurally: it has no public constructor, so callers cannot bypass the cache by calling std::sync::Arc::new directly.

Structs

Arc

A reference-counted pointer that can only be constructed through a crate::ValueCache.

UniqueValueCache

A bounded cache for values that are inserted and then taken out (moved), not cloned.

ValueCache

A concurrent cache with efficient eviction and single-allocation guarantees.

Constants

DEFAULT_CLEANUP_INTERVAL_SECS

Default interval between dead-entry cleanup sweeps of the weak index.