Function transformModuleEvents

packages/computer/src/runtime/runtime.ts:338–411

(
  source: ReadableStream<WorkspaceRuntimeEvent>,
  encoding: E | undefined,
)

}

function transformModuleEvents<E extends ExecEncoding>(
  source: ReadableStream<WorkspaceRuntimeEvent>,
  encoding: E | undefined,
): ReadableStream<WorkspaceRuntimeEvent<E>> {
  if (encoding !== "utf8") {
    return source as ReadableStream<WorkspaceRuntimeEvent<E>>;
  }
  const stdoutDecoder = new TextDecoder();
  const stderrDecoder = new TextDecoder();
  let stdoutMeta: { id: string; seq: number } | undefined;
  let stderrMeta: { id: string; seq: number } | undefined;
  let lastSeq = 0;
  const enqueue = (
    controller: TransformStreamDefaultController<WorkspaceRuntimeEvent<E>>,
    event: WorkspaceRuntimeEvent<E>,
  ) => {
    lastSeq = event.seq;
    controller.enqueue(event);
  };
  const flushPending = (
    controller: TransformStreamDefaultController<WorkspaceRuntimeEvent<E>>,
    beforeSeq?: number,
  ) => {
    const pending: WorkspaceRuntimeEvent<E>[] = [];
    const stdout = stdoutDecoder.decode();
    const stderr = stderrDecoder.decode();
    if (stdout && stdoutMeta) {
      pending.push({
        ...stdoutMeta,
        name: "stdout",
        value: stdout,
      } as WorkspaceRuntimeEvent<E>);
    }
    if (stderr && stderrMeta) {
      pending.push({
        ...stderrMeta,
        name: "stderr",
        value: stderr,
      } as WorkspaceRuntimeEvent<E>);
    }
    pending.sort((a, b) => a.seq - b.seq);
    const span = beforeSeq !== undefined && beforeSeq > lastSeq ? beforeSeq - lastSeq : 1;
    let index = 0;
    for (const event of pending) {
      index += 1;
      enqueue(controller, {
        ...event,
        seq: lastSeq + (span * index) / (pending.length + 1),
      } as WorkspaceRuntimeEvent<E>);
    }
    stdoutMeta = undefined;
    stderrMeta = undefined;
  };
  return source.pipeThrough(
    new TransformStream<WorkspaceRuntimeEvent, WorkspaceRuntimeEvent<E>>({
      transform(event, controller) {
        if (event.name === "stdout" || event.name === "stderr") {
          if (event.name === "stdout") stdoutMeta = { id: event.id, seq: event.seq };