Struct MappingStore 

pub struct MappingStore { /* private fields */ }

Thread-safe concurrent one-way replacement store.

Caches forward mappings for per-run consistency (same input always produces the same output within a run). There is no reverse map, no journal, and no persistence — replacements are one-way only.

See the module-level documentation for concurrency and memory details.

Implementations

impl MappingStore

pub fn new( generator: Arc<dyn ReplacementGenerator>, capacity_limit: Option<usize>, ) -> Self

Create a new, empty mapping store.

Arguments

• generator — replacement strategy (HMAC or random).
• capacity_limit — optional max number of unique mappings.

pub fn with_expected_capacity( generator: Arc<dyn ReplacementGenerator>, capacity_limit: Option<usize>, expected: usize, ) -> Self

Create a store pre-sized for expected entries (avoids rehashing).

pub fn get_or_insert( &self, category: &Category, original: &str, ) -> Result<CompactString>

Get or create the sanitized replacement for (category, original).

This is the primary API for one-way sanitization.

Thread-safety: Uses DashMap::entry() which holds a shard-level lock only for the duration of the insert closure. The generator is called inside the lock, but generation is fast (one HMAC or one RNG call). Capacity enforcement uses compare_exchange to prevent TOCTOU over-insertion (C-1 fix).

Per-run consistency: Once a value is mapped, all subsequent lookups return the same sanitized value (first-writer-wins).

Errors

Returns SanitizeError::CapacityExceeded if the store has reached its configured capacity limit.

pub fn forward_lookup( &self, category: &Category, original: &str, ) -> Option<CompactString>

Look up an existing forward mapping without creating one.

pub fn len(&self) -> usize

Number of unique mappings in the store.

pub fn is_empty(&self) -> bool

Whether the store is empty.

pub fn clear(&mut self)

Remove all mappings, zeroizing the original plaintexts.

This is useful for resetting the store between runs without dropping and recreating it.

pub fn iter( &self, ) -> impl Iterator<Item = (Category, CompactString, CompactString)> + '_

Iterate over all mappings. Yields (category, original, sanitized).

Note: iteration over DashMap is not snapshot-consistent if concurrent inserts are happening. Call this after all workers have finished.

Trait Implementations

impl Drop for MappingStore

F-09 fix: zeroize original keys stored in the forward map on drop. This prevents sensitive plaintext values from lingering on the heap after the store is no longer needed. Uses safe Zeroize on Strings.

fn drop(&mut self)

Executes the destructor for this type.