Struct StoragePrefetchEngine 

pub struct StoragePrefetchEngine {
    pub config: PeConfig,
    pub access_history: VecDeque<PeAccessEvent>,
    pub coaccesses: HashMap<String, CoAccessPair>,
    pub recent_cids: VecDeque<String>,
    pub pattern_state: HashMap<String, Vec<u64>>,
    /* private fields */
}

Intelligent prefetch engine: records access events, identifies co-access pairs, detects per-CID access patterns, and generates prioritised prefetch hints.

Fields

config: PeConfig

Engine configuration (immutable after construction).

access_history: VecDeque<PeAccessEvent>

Ordered history of recent access events (front = oldest).

coaccesses: HashMap<String, CoAccessPair>

Co-access pairs keyed by "<cid_a>:<cid_b>" (cid_a < cid_b).

recent_cids: VecDeque<String>

CIDs seen in recent accesses (last config.pattern_window entries).

pattern_state: HashMap<String, Vec<u64>>

Per-CID list of recent access timestamps (last pattern_window entries).

Implementations

impl StoragePrefetchEngine

pub fn new(config: PeConfig) -> Self

Create a new engine with the given configuration.

pub fn record_access(&mut self, event: PeAccessEvent) -> Vec<PePrefetchHint>

Record an access event.

Side effects:

1. Appends event to access_history.
2. Updates co-access pairs for every event within coaccess_window_ms.
3. Updates pattern_state for the accessed CID.
4. Returns prefetch hints for the accessed CID.

pub fn generate_hints(&self, cid: &str, now: u64) -> Vec<PePrefetchHint>

Generate prefetch hints for cid at the given now timestamp.

Returns up to config.max_prefetch_hints hints sorted by descending coaccess_count * recency_weight.

pub fn detect_pattern(&self, cid: &str) -> PeAccessPattern

Detect the access pattern for a given CID using the last pattern_window recorded timestamps.

Decision logic (in order):

1. Repeated — ≥ 3 timestamps in the pattern state.
2. Sequential — inter-access std-dev < 20 % of the mean interval.
3. Unknown — otherwise.

pub fn top_coaccessed<'a>( &'a self, cid: &str, n: usize, ) -> Vec<&'a CoAccessPair>

Return the top n co-access pairs involving cid, sorted by coaccess_count descending.

pub fn evict_stale_pairs(&mut self, max_age_ms: u64, now: u64) -> usize

Remove co-access pairs not seen within the last max_age_ms milliseconds.

Returns the number of pairs removed.

pub fn total_pairs(&self) -> usize

Return the total number of co-access pairs currently tracked.

pub fn history_len(&self) -> usize

Return the number of events in the access history buffer.

pub fn most_accessed_cids(&self, n: usize) -> Vec<(String, usize)>

Return the top n most-accessed CIDs by total appearance in access_history, as (cid, count) pairs sorted by count descending.

pub fn stats(&self) -> PePrefetchStats

Return aggregate statistics.