Function scanWire

apps/vis/server/src/lib/session-store.ts:333–361

(path: string)

}

async function scanWire(path: string): Promise<{ count: number; protocolVersion: string }> {
  const stream = createReadStream(path, { encoding: 'utf8' });
  const rl = createInterface({ input: stream, crlfDelay: Infinity });
  let count = 0;
  let protocolVersion: string | null = null;
  for await (const line of rl) {
    if (line.length === 0) continue;
    if (protocolVersion === null) {
      // Strict: the first non-empty line MUST be a well-formed
      // `metadata` record. Otherwise the list-view health would say
      // "ok" while the wire-reader rejects the file on open.
      let parsed: { type?: unknown; protocol_version?: unknown };
      try {
        parsed = JSON.parse(line) as typeof parsed;
      } catch {
        throw new Error(`wire metadata is not valid JSON at line 1`);
      }
      if (parsed.type !== 'metadata' || typeof parsed.protocol_version !== 'string') {
        throw new Error(`wire is missing a metadata header on line 1`);
      }
      protocolVersion = parsed.protocol_version;
    }
    count += 1;
  }
  if (protocolVersion === null) {
    throw new Error('wire file is empty');
  }
  return { count, protocolVersion };
}

function parseTs(input: string | undefined): number {
  if (!input) return 0;