Struct CursorState 

pub struct CursorState { /* private fields */ }

In-memory per-stream cursor state for data marker capture.

Assigns a StreamSlot lazily on the first observation of a topic, advances each slot’s cursor (cumulative count and highest ts_init) on every message in O(1) with no I/O, and builds a DataCursorSnapshot of the slots that changed since the previous snapshot.

Implementations

impl CursorState

pub fn new() -> Self

Creates a new empty CursorState.

pub fn advance( &mut self, topic: Topic, data_cls: DataClass, identifier: &str, ts_init: UnixNanos, ) -> (StreamSlot, u32)

Advances the cursor for topic, assigning a slot on its first observation.

Returns the stream slot and the same_ts_ordinal: the running ordinal among records sharing the current ts_init within the slot, which resets to zero when ts_init advances (only the high-fidelity path reads it). Bumps the slot’s cumulative count, raises its highest ts_init, and marks it dirty so the next build_snapshot includes it. A first observation also queues a StreamDictEntry for take_new_dict_entries.

Panics

Panics if the number of distinct streams exceeds u32::MAX.

pub fn take_new_dict_entries(&mut self) -> Vec<StreamDictEntry>

Removes and returns the dict entries queued since the previous call.

Each StreamDictEntry is produced once, when its slot is first assigned by advance.

pub fn build_snapshot( &mut self, marker_seq: u64, event_seq_before: u64, ts_init: UnixNanos, ) -> Option<DataCursorSnapshot>

Builds a snapshot of every slot that advanced since the previous snapshot, clearing the dirty set.

Returns None when no slot has advanced, so a quiet interval writes nothing.

Trait Implementations

impl Debug for CursorState

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

Formats the value using the given formatter.

impl Default for CursorState

fn default() -> CursorState

Returns the “default value” for a type.