Struct DedupCache 

pub struct DedupCache { /* private fields */ }

Session-scoped deduplication cache.

Maintains a bounded LRU of recent (content_hash → tool_call_id) mappings. A single instance is intended to live for one agent session (or one context partition, whichever is shorter).

Implementations

impl DedupCache

pub fn with_capacity(capacity: usize) -> Self

Construct a cache with the given LRU capacity.

Recommended default: 5. Empirically, 95% of deduplication savings in Claude Code logs come from the three most-recent responses; capacities above ~5 yield diminishing returns.

pub fn partition(&self) -> u64

Current context partition counter. Increments on each on_compaction_boundary() call.

pub fn len(&self) -> usize

Number of entries currently cached.

pub fn is_empty(&self) -> bool

true if no entries are cached.

pub fn check(&mut self, hash: &ContentHash) -> DedupDecision

LRU lookup that refreshes recency on hits.

A match promotes the entry to the most-recently-used position, so repeated references protect frequently-used content from eviction when new responses are inserted.

pub fn insert( &mut self, hash: ContentHash, tool_call_id: impl Into<String>, tool_kind: ToolKind, file_path_hash: Option<String>, tool_name: impl Into<String>, )

Insert a fresh response. Evicts the oldest entry if the cache is at capacity.

tool_name is the anonymized tool that produced the response — used by Self::invalidate_by_tool for Paper 3 cross-tool invalidation. Pass an empty string when the tool is unknown (cross-tool invalidation will simply never match it).

pub fn insert_with_body( &mut self, hash: ContentHash, tool_call_id: impl Into<String>, tool_kind: ToolKind, file_path_hash: Option<String>, body: Arc<String>, tool_name: impl Into<String>, )

Insert a fresh response and retain its body for Type-2 (near-duplicate) hint extraction. Used when dedup.near_ref_enabled is on; otherwise prefer Self::insert to avoid the extra allocation.

pub fn find_near_ref( &self, new_body: &str, config: &NearRefConfig, ) -> Option<(String, Vec<DeltaField>)>

Look for a Type-2 near-duplicate match in the cache. Walks entries from newest to oldest; the first one whose retained body produces a valid delta against new_body (per extract_delta) wins. Returns the matched tool_call_id plus the field-level deltas.

Returns None when:

• no entry has a body snapshot,
• no entry’s delta against new_body clears the eligibility gate (size, scalar-only, key-set match),
• or new_body itself is too short to bother.

pub fn invalidate_file(&mut self, file_path_hash: &str) -> usize

Invalidate all cached FileRead entries whose path hash matches. Returns the number of entries dropped.

Callers typically invoke this from a FileMutate tool response handler to prevent emitting stale hints for a subsequently re-read file.

pub fn invalidate_by_tool(&mut self, invalidates: &[String]) -> usize

Invalidate every entry whose tool_name appears in invalidates. Drives Paper 3 cross-tool invalidation: a writer (update_issue, Edit, Write, …) declares which read tools its ToolValueModel.invalidates list, and the runtime calls this method right after the writer’s response is processed.

Returns the number of entries dropped. Empty invalidates is a no-op (returns 0) — used by tools that do not affect any cache.

pub fn on_compaction_boundary(&mut self)

Clear the cache and advance the partition counter.

Called when the LLM host emits a context-compaction boundary (Claude Code: compact_boundary event). Older references are no longer reachable from the agent’s context, so they must not be referenced by new hints.

Trait Implementations

impl Debug for DedupCache

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

Formats the value using the given formatter.

impl Default for DedupCache

fn default() -> Self

Equivalent to DedupCache::with_capacity(5).