Module snapshot 

Core types for entity snapshotting.

A repo with #[es_repo(snapshot)] persists, in the same statement as the events it appends, an author-defined state S (the fold of events 1..=k) into <tbl>_snapshots. Hydration then loads S plus only the events after k in one round trip.

Structs

SnapshotRecord

A persisted snapshot as loaded: the state plus the metadata of the events it summarises.

Enums

NoSnapshot

The default S of EntityEvents<E, S>: this entity has no snapshot.

Replay

One item of an entity’s replay. The snapshot, when present, is the FIRST item in forward order and the LAST item in reverse order. Deliberately exhaustive — do not add #[non_exhaustive].

Constants

NO_SNAPSHOT_FINGERPRINT

Matches no stored snapshot; binds on full-history loads and is NoSnapshot’s fingerprint.

Traits

EsSnapshot

Implemented by #[derive(EsSnapshot)] for user state types and by hand for NoSnapshot.

GuardWithoutSnapshotClause

Reached by idempotency_guard! when a stream yields Replay::Snapshot but the guard has no snapshot: clause. Only NoSnapshot (and SnapshotRecord<NoSnapshot>) implement it, so on a real snapshot this is a compile error with the message below.

HeadSnapshot

Implemented by every entity whose repo enables snapshot.

IntoReplay

Normalises idempotency_guard! input: a plain &E stream (today’s call sites) and a replay() stream both become Replay. Do not implement for other types.