Struct MemoryBackend 

pub struct MemoryBackend { /* private fields */ }

In-memory implementation of EventStore.

Stores entries densely in a Vec keyed by seq - 1 plus one [IndexMap] per IndexKind for the sidecar indices. Hash recomputation on read is structurally redundant (entries live in process memory) but kept for parity with persistent backends so callers see uniform behavior.

One backend instance owns at most one open run at a time. Sealing the open run leaves the manifest and entries readable until the next EventStore::open_run call replaces them with a fresh run. Reopening while a Running run still exists returns EventStoreError::CrashedPredecessor so callers exercise the same crash-recovery path persistent backends surface on reopen.

Implementations

impl MemoryBackend

pub fn new() -> Self

Creates a new empty MemoryBackend with no run open.

Trait Implementations

impl Debug for MemoryBackend

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

Formats the value using the given formatter.

impl Default for MemoryBackend

fn default() -> MemoryBackend

Returns the “default value” for a type.

impl EventStore for MemoryBackend

fn open_run(&mut self, manifest: RunManifest) -> Result<(), EventStoreError>

Opens an existing run or creates a new one with the supplied manifest.

fn append_batch( &mut self, entries: &[AppendEntry], ) -> Result<u64, EventStoreError>

Appends a batch of (entry, index_keys) pairs in a single backend transaction.

fn scan_range( &self, from: u64, to: u64, direction: ScanDirection, ) -> Result<Vec<EventStoreEntry>, EventStoreError>

Scans entries by seq over the inclusive range [from, to].

fn scan_seq(&self, seq: u64) -> Result<Option<EventStoreEntry>, EventStoreError>

Reads a single entry by seq.

fn lookup( &self, kind: IndexKind, key: &str, ) -> Result<Option<u64>, EventStoreError>

Looks up the first seq recorded under the given index key.

fn iter_index_keys( &self, kind: IndexKind, ) -> Result<Vec<(String, u64)>, EventStoreError>

Enumerates every (key, seq) pair stored under the given secondary index.

fn record_snapshot_anchor( &mut self, anchor: SnapshotAnchor, ) -> Result<(), EventStoreError>

Records the latest cache snapshot anchor for the open run.

fn latest_snapshot_anchor( &self, ) -> Result<Option<SnapshotAnchor>, EventStoreError>

Returns the latest recorded snapshot anchor for the open run.

fn seal(&mut self, status: RunStatus) -> Result<(), EventStoreError>

Seals the open run with the given final status and persists the manifest update.

fn manifest(&self) -> Result<RunManifest, EventStoreError>

Returns the current manifest snapshot.

fn high_watermark(&self) -> Result<u64, EventStoreError>

Returns the largest seq durably acknowledged for the open run.