Function runWorkerJob

src/utils/png-worker-client.ts:138–168

* Sends one job to the worker. Rejects with `PngWorkerUnavailableError` for * worker-infrastructure failures (the single unavailability channel) and with * the reconstructed job `AppError` for job-level failures (e.g. corrupt PNG).

(
  job: PngWorkerJobFor<Kind>,
)

 * the reconstructed job `AppError` for job-level failures (e.g. corrupt PNG).
 */
function runWorkerJob<Kind extends PngWorkerJobKind>(
  job: PngWorkerJobFor<Kind>,
): Promise<PngWorkerJobResultFor<Kind>> {
  const activeWorker = obtainWorker();
  if (!activeWorker) {
    return Promise.reject(new PngWorkerUnavailableError('PNG worker is unavailable'));
  }
  nextJobId += 1;
  const id = nextJobId;
  return new Promise<PngWorkerJobResultFor<Kind>>((resolve, reject) => {
    pendingJobs.set(id, {
      // The worker answers each request id with the result of the same kind.
      resolve: resolve as (result: PngWorkerJobResult) => void,
      reject,
    });
    updateWorkerRef();
    try {
      activeWorker.postMessage({ ...job, id });
    } catch (error) {
      // Job-specific send failure (e.g. DataCloneError): fall back to the sync
      // path for this call without permanently disabling the worker.
      pendingJobs.delete(id);
      updateWorkerRef();
      reject(
        new PngWorkerUnavailableError(
          `failed to post job to PNG worker: ${error instanceof Error ? error.message : String(error)}`,
        ),
      );
    }
  });
}

/** Runs a job on the worker, falling back to `runSync` when it is unavailable. */
async function runPngJob<Kind extends PngWorkerJobKind>(