Struct TrackConsumer 

pub struct TrackConsumer {
    pub info: Track,
    /* private fields */
}

A consumer for a track, used to read groups.

Fields

info: Track

Implementations

impl TrackConsumer

pub fn poll_next_group( &mut self, waiter: &Waiter, ) -> Poll<Result<Option<GroupConsumer>>>

Poll for the next group without blocking.

Returns Poll::Ready(Ok(Some(group))) when a group is available, Poll::Ready(Ok(None)) when the track is finished, Poll::Ready(Err(e)) when the track has been aborted, or Poll::Pending when no group is available yet.

pub async fn next_group(&mut self) -> Result<Option<GroupConsumer>>

Return the next group in order.

NOTE: This can have gaps if the reader is too slow or there were network slowdowns.

pub fn poll_get_group( &self, waiter: &Waiter, sequence: u64, ) -> Poll<Result<Option<GroupConsumer>>>

Poll for the group with the given sequence, without blocking.

pub async fn get_group(&self, sequence: u64) -> Result<Option<GroupConsumer>>

Block until the group with the given sequence is available.

Returns None if the group is not in the cache and a newer group exists.

pub fn poll_closed(&self, waiter: &Waiter) -> Poll<Result<()>>

Poll for track closure, without blocking.

pub async fn closed(&self) -> Result<()>

Block until the track is closed.

Returns Ok() is the track was cleanly finished.

pub fn is_clone(&self, other: &Self) -> bool

pub fn poll_finished(&mut self, waiter: &Waiter) -> Poll<Result<u64>>

Poll for the total number of groups in the track.

pub async fn finished(&mut self) -> Result<u64>

Block until the track is finished, returning the total number of groups.

pub fn start_at(&mut self, sequence: u64)

Start the consumer at the specified sequence.

pub fn latest(&self) -> Option<u64>

Return the latest sequence number in the track.

pub fn produce(&self) -> Result<TrackProducer>

Upgrade this consumer back to a TrackProducer sharing the same state.

This enables zero-copy track sharing between broadcasts: subscribe to a track, then crate::BroadcastProducer::insert_track the producer into another broadcast. Both broadcasts serve the same underlying track data with no forwarding overhead.

Shared Ownership

The returned producer shares state with the original track. Mutations (appending groups, finishing, aborting) through either producer affect all consumers of the track. The returned producer keeps the track alive (prevents auto-close) as long as it exists, even if the original producer is dropped.

Trait Implementations

impl Clone for TrackConsumer

fn clone(&self) -> TrackConsumer

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.