Struct ByteMerge 

pub struct ByteMerge { /* private fields */ }

The one bounded multi-input primitive in the byte layer: N byte sources reduced to one output stream. See the module docs.

Implementations

impl ByteMerge

pub fn new(policy: MergePolicy, num_sources: usize, max_queued: usize) -> Self

Construct a merge for num_sources sources (0..num_sources), applying policy, with its output queue bounded to max_queued messages.

Panics if num_sources == 0, max_queued == 0, or (for MergePolicy::Failover) primary/secondary are not both within 0..num_sources — all three are construction-time configuration mistakes, not remote input, so they panic rather than returning a Result a caller could ignore.

pub fn num_sources(&self) -> usize

How many sources this merge accepts feed calls from.

pub fn len(&self) -> usize

Messages currently queued, awaiting ByteMerge::poll. Never exceeds the max_queued bound this merge was constructed with.

pub fn is_empty(&self) -> bool

true if no messages are currently queued.

pub fn feed( &mut self, source: SourceId, msg: Bytes, at: Timestamp, ) -> Result<(), MergeError>

Feed one discrete message from source, observed at at.

Whether it is forwarded to ByteMerge::poll depends on the policy: every message is forwarded under MergePolicy::FirstArrival; under MergePolicy::Failover only the currently-active source’s messages are (see that variant’s docs for exactly when that is, and the switch-back rule).

Returns MergeError::UnknownSource if source is out of range, or MergeError::QueueFull if the output queue is already at its bound — in both cases nothing from this call is buffered.

pub fn poll(&mut self) -> Option<(Bytes, Timestamp)>

Pull the next merged message, in the order it was forwarded by ByteMerge::feed.

pub fn next_deadline(&self) -> Option<Timestamp>

When ByteMerge::on_deadline should next be called to check a MergePolicy::Failover silence timeout.

None under MergePolicy::FirstArrival (arrival-driven, no clock needed) and under Failover before primary has produced its first message (see that variant’s docs).

pub fn on_deadline(&mut self, now: Timestamp)

Drive time-based transitions: under MergePolicy::Failover, switch to secondary if primary has been silent for at least silence_timeout as of now. A no-op under MergePolicy::FirstArrival.