Struct Deduplicator 

pub struct Deduplicator { /* private fields */ }

Deduplicator for tracking seen messages and preventing duplicates.

Supports two modes:

• HashMap mode: exact tracking with FIFO eviction (original behavior)
• Bloom filter mode: O(1) memory with probabilistic duplicate detection

Implementations

impl Deduplicator

pub fn new() -> Self

Creates a new deduplicator with default configuration.

pub fn with_config(config: DeduplicatorConfig) -> Self

Creates a new deduplicator with custom configuration.

pub fn is_exact(&self) -> bool

Returns true when deduplication is exact (HashMap mode): a positive Self::is_duplicate answer is then authoritative. In bloom mode (false) a positive answer may be a false positive (~1% with default settings), so callers must not treat a hit as proof of a prior send.

pub fn is_duplicate(&self, message_id: &MessageId) -> bool

Checks if a message has been seen before.

Arguments

• message_id - The message ID to check

Returns

Returns true if the message has been seen, false otherwise.

Note: In bloom filter mode, this may return false positives (claiming a message is a duplicate when it isn’t). The false positive rate is typically below 1% with default settings.

pub fn is_duplicate_mut(&mut self, message_id: &MessageId) -> bool

Checks if a message has been seen before (mutable version for bloom rotation and LRU access tracking).

pub fn mark_seen(&mut self, message_id: MessageId) -> bool

Marks a message as seen.

Arguments

• message_id - The message ID to mark as seen

Returns

Returns true if this is a new message, false if it was already seen.

pub fn unmark_seen(&mut self, message_id: &MessageId) -> bool

Removes a message from the seen set so a future copy is processed fresh instead of being treated as a duplicate.

Intended for receivers that reject a message after marking it seen (e.g. an encryption-policy or security-gate rejection): forgetting the id makes a replay re-enter the same gate — and be rejected again without a delivery ACK — instead of hitting the duplicate re-ACK path, which would confirm to an injector that the target is online.

Returns

Returns true if the message was tracked and has been removed. Bloom filters do not support removal, so in bloom filter mode this is a no-op returning false: a replayed rejected message is treated as a duplicate until its filter window rotates out.

pub fn cleanup_expired(&mut self) -> usize

Removes expired entries that exceed the retention time.

Returns

Returns the number of entries removed.

Note: In bloom filter mode, expiration is handled automatically through filter rotation, so this returns 0.

pub fn tracked_count(&self) -> usize

Gets the number of messages currently being tracked.

Note: In bloom filter mode, this returns an estimate based on insertion count.

pub fn clear(&mut self)

Clears all tracked messages.

pub fn is_tracked(&self, message_id: &MessageId) -> bool

Checks if a message ID is being tracked (seen).

pub fn is_bloom_filter_mode(&self) -> bool

Returns whether bloom filter mode is active.

pub fn stats(&self) -> DeduplicatorStats

Gets statistics about the deduplicator.

pub fn estimated_memory_bytes(&self) -> usize

Gets the estimated memory usage in bytes.

Trait Implementations

impl Default for Deduplicator

fn default() -> Self

Returns the “default value” for a type.