Struct SectionWriter 

pub struct SectionWriter { /* private fields */ }

One shard’s side of a shared log: assigns the shard’s LSNs and encodes its records, once, into the section its next batch carries. Pure.

Implementations

impl SectionWriter

pub fn new(next_lsn: Lsn) -> Self

The shard’s next record will be next_lsn.

pub fn next_lsn(&self) -> Lsn

pub fn last_lsn(&self) -> Lsn

pub fn has_pending(&self) -> bool

pub fn append<S: AsRef<str>, B: AsRef<[u8]>>( &mut self, rec: &Record<S, B>, ) -> Result<Lsn, TooLarge>

Appends one record and returns its LSN.

pub fn last_encoded(&self) -> &[u8]

The canonical encoding of the record most recently appended (empty once its section was taken).

pub fn discard(&mut self) -> Option<(u32, u64, Lsn)>

Forgets the records appended since the last call, keeping the buffer, for storage that holds nothing (memory mode): their count, bytes and last LSN.

pub fn take(&mut self) -> Option<Batch>

Takes every record not taken yet as one section.

pub fn take_up_to(&mut self, max: usize) -> Option<Batch>

Takes the oldest records not taken yet as one section of at most max bytes (one record at least); the rest stay for the next call. When everything fits, which is every call of a shard that keeps up, the section is the writer’s buffer itself: nothing is copied.

Trait Implementations

impl Clone for SectionWriter

fn clone(&self) -> SectionWriter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SectionWriter

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

Formats the value using the given formatter.