Struct WalWriter 

pub struct WalWriter { /* private fields */ }

Where the next batch goes. Pure: the I/O layer writes the bytes.

Implementations

impl WalWriter

pub fn resume( group: u32, life: u64, segment: u64, salt: u64, segment_bytes: u64, offset: u64, next_seq: u64, prev: u64, ) -> Self

Continues the chain after recovery: the next batch is next_seq, its prev is prev, and it goes at offset of segment, right after the accepted prefix (so the chain has one possible next position). Bytes a torn write left there are overwritten; any beyond the new batch can never join the chain.

pub fn next_seq(&self) -> u64

pub fn segment(&self) -> u64

pub fn offset(&self) -> u64

pub fn roll( &mut self, segment: u64, salt: u64, segment_bytes: u64, now_ms: u64, ) -> WalHeader

Moves to a new segment with no batch to carry there: the header to write at its start, durably, before anything else uses it. The chain continues there exactly as after a roll (the header names the next batch and the checksum the chain ended with), so the segments before it can be retired once nothing needs their batches.

pub fn place( &mut self, sections: &[SectionRef<'_>], acked: u64, pipelined: bool, now_ms: u64, next_segment: impl FnOnce() -> (u64, u64, u64), ) -> Placed

Encodes the next batch. pipelined: another write may start before this one completes, so the batch is padded to the end of its last block (see batch_span) and the next one starts in a block of its own. Without it, the next write shares this batch’s last block and must not start before this one completed. next_segment supplies (number, salt, size) when the batch does not fit in the current segment.

Trait Implementations

impl Clone for WalWriter

fn clone(&self) -> WalWriter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WalWriter

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

Formats the value using the given formatter.