Struct Writer 

pub struct Writer { /* private fields */ }

A memory-mapped file into which this writer adds new snapshot.

Implementations

impl Writer

Public interface of the writer.

pub fn commit( &mut self, data: &[u8], ) -> Result<SnapshotIndex, WriterCommitError>

Insert some data into the atomic log of the shared memory.

pub fn commit_with<T>( &mut self, data: &[u8], intermediate: impl FnOnce(PreparedTransaction<'_>) -> Option<T>, ) -> Result<(SnapshotIndex, T), WriterCommitError>

Insert some data into the atomic log of the shared memory.

This also invokes a function such that it’s effects are sequenced after the reservation of the new slot but before committing the data. The function can also introduce changes that appear correctly from the semantics view of the ring. Changes to the tail can be made via the passed PreparedTransaction object.

pub fn snapshot_at(&self, idx: SnapshotIndex) -> Snapshot

Read the snapshot associated with a written index.

pub fn read(&self, snapshot: &Snapshot, buffer: &mut [u8])

Read data described by a snapshot, with discovered metadata in the file.

pub fn valid(&self, into: &mut impl Extend<Snapshot>)

Collect all currently valid snapshot entries.

pub fn tail(&self) -> &[AtomicU64]

Access the tail of the underlying shared memory file.

This refers to the portion of the file after the header, the entry ring, and the data ring buffer. This data can not be referenced by an entry directly and belongs to arbitrary use by the caller.