Struct PluginCache 

pub struct PluginCache { /* private fields */ }

Plugin cache for performance optimization.

Scope: f64 only

CachedPlugin::plugin is monomorphized to Box<dyn OptimizerPlugin<f64>> – there is no generic PluginCache<A>. PluginRegistry::create_optimizer::<A> only consults this cache when A = f64; a call with A = f32 (or any other Float impl) always goes straight to the factory and never touches instances, stats.hits, or stats.misses. This is a deliberate scope limitation, not an oversight: caching f32 instances too would need either a second, separately-bounded HashMap or an Any-erased value type, and nothing in this crate currently creates enough f32 optimizers through the registry to justify that complexity.

Cache key and correctness

Entries are keyed by plugin name, but a lookup is only a hit when the caller’s OptimizerConfig also equals the config the cached instance was built with (CachedPlugin::config). A name-only key would let a caller requesting e.g. a different learning_rate silently receive an instance built with someone else’s config – that would be exactly the kind of fabricated-success this crate’s stub-removal pass exists to eliminate, so a config mismatch is treated as a miss (the stale entry is replaced by a freshly created one) rather than returned.

Eviction

Bounded by RegistryConfig::max_cache_size: inserting past the limit evicts the least-recently-used entry first. “Recently used” is tracked with a monotonically increasing u64 sequence number bumped on every insert and every hit, not a wall-clock timestamp – two cache operations completing within the same clock tick (common on fast hardware or under #[test]) would otherwise tie under SystemTime-based LRU and evict a nondeterministically-chosen entry.

Trait Implementations

impl Debug for PluginCache

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

Formats the value using the given formatter.