Struct Reader 

pub struct Reader<E: Context, V: CodecShared> { /* private fields */ }

Delivers a Queue’s committed items and tracks their acknowledgement.

Acknowledgements are in-memory, and Queue::sync prunes items below the ack floor.

Implementations

impl<E: Context, V: CodecShared> Reader<E, V>

pub async fn recv(&mut self) -> Result<Option<(u64, V)>, Error>

Receive the next unacknowledged item, waiting if necessary.

This method is designed for use with select!. It will:

1. Return immediately if an unacked item has been published
2. Wait for the queue to publish new items otherwise
3. Return None once the queue is dropped and every published item has been delivered

Errors

Returns an error if the underlying storage operation fails.

pub async fn try_recv(&mut self) -> Result<Option<(u64, V)>, Error>

Try to dequeue the next unacknowledged item without waiting.

Returns None immediately if no unacked item has been published.

Errors

Returns an error if the underlying storage operation fails.

pub fn is_acked(&self, position: u64) -> bool

Returns whether a specific position has been acknowledged.

pub fn ack(&mut self, position: u64) -> Result<(), Error>

Mark the item at position as processed (in-memory only). The item is skipped on subsequent receives. If this creates a contiguous run from the ack floor, the floor advances.

Errors

Returns Error::PositionOutOfRange if position has not been published.

pub fn ack_up_to(&mut self, up_to: u64) -> Result<(), Error>

Acknowledge all items in [ack_floor, up_to) by advancing the floor directly. More efficient than calling Self::ack in a loop.

Errors

Returns Error::PositionOutOfRange if up_to exceeds the published items.

pub const fn ack_floor(&self) -> u64

Returns the current ack floor.

All items at positions less than this value are considered acknowledged.

pub const fn read_position(&self) -> u64

Returns the current read position.

This is the position of the next item Self::try_recv will check.

pub fn is_empty(&self) -> bool

Returns whether every published item has been acknowledged.

pub fn reset(&mut self)

Reset the read position to the ack floor so the reader re-delivers every unacknowledged item.