robonen
008d85a8fd
Hand-built CRDT primitives: Lamport clock + version vectors, op-log, LWW register/map, RGA sequence, fractional indexing, marks store, sync encode, and doc/replica. Includes eslint flat config + composite tsconfig.
42 lines
1.1 KiB
TypeScript
42 lines
1.1 KiB
TypeScript
import type { OpId, SiteId } from './id';
|
|
|
|
/**
|
|
* Tracks the highest clock seen per site, assuming each site emits dense clocks
|
|
* (1, 2, 3, …). Used to deduplicate ops and to compute deltas during sync.
|
|
*/
|
|
export class VersionVector {
|
|
private readonly clocks = new Map<SiteId, number>();
|
|
|
|
/** Record that an op has been seen. */
|
|
observe(id: OpId): void {
|
|
if (id.clock > this.get(id.site))
|
|
this.clocks.set(id.site, id.clock);
|
|
}
|
|
|
|
/** Highest clock seen for a site (0 if none). */
|
|
get(site: SiteId): number {
|
|
return this.clocks.get(site) ?? 0;
|
|
}
|
|
|
|
/** Whether an op id has already been seen. */
|
|
has(id: OpId): boolean {
|
|
return this.get(id.site) >= id.clock;
|
|
}
|
|
|
|
/** Plain-object snapshot for transport. */
|
|
toJSON(): Record<SiteId, number> {
|
|
return Object.fromEntries(this.clocks);
|
|
}
|
|
|
|
static fromJSON(snapshot: Record<SiteId, number>): VersionVector {
|
|
const vv = new VersionVector();
|
|
for (const site in snapshot)
|
|
vv.clocks.set(site, snapshot[site]!);
|
|
return vv;
|
|
}
|
|
|
|
clone(): VersionVector {
|
|
return VersionVector.fromJSON(this.toJSON());
|
|
}
|
|
}
|