Function createNodeBackendInternal

packages/node/src/backend/nodeBackend.ts:126–1266

(opts: NodeBackendInternalOpts = {})

export { selectNodeBackendExecutionMode };

export function createNodeBackendInternal(opts: NodeBackendInternalOpts = {}): NodeBackend {
  const frameAudit = createFrameAuditLogger("backend");
  const cfg = opts.config ?? {};
  const fpsCap = parseBoundedPositiveIntOrThrow(
    "fpsCap",
    cfg.fpsCap,
    DEFAULT_FPS_CAP,
    MAX_SAFE_FPS_CAP,
  );
  const requestedExecutionMode = cfg.executionMode ?? "auto";
  const executionModeSelection = selectNodeBackendExecutionMode({
    requestedExecutionMode,
    fpsCap,
    hasAnyTty: hasInteractiveTty(),
    ...(opts.nativeShimModule === undefined ? {} : { nativeShimModule: opts.nativeShimModule }),
  });
  const executionMode = executionModeSelection.selectedExecutionMode;
  if (executionModeSelection.fallbackReason !== null && frameAudit.enabled) {
    frameAudit.emit("backend.executionModeFallback", {
      requestedExecutionMode,
      resolvedExecutionMode: executionModeSelection.resolvedExecutionMode,
      selectedExecutionMode: executionMode,
      reason: executionModeSelection.fallbackReason,
    });
  }
  if (executionMode === "inline") {
    return createNodeBackendInlineInternal(opts);
  }
  const requestedDrawlistVersion = ZR_DRAWLIST_VERSION_V1;
  const maxEventBytes = parseBoundedPositiveIntOrThrow(
    "maxEventBytes",
    cfg.maxEventBytes,
    DEFAULT_MAX_EVENT_BYTES,
    MAX_SAFE_EVENT_BYTES,
  );
  const frameTransportMode =
    cfg.frameTransport === "transfer" || cfg.frameTransport === "sab" ? cfg.frameTransport : "auto";
  const frameSabSlotCount = parsePositiveIntOr(cfg.frameSabSlotCount, FRAME_SAB_SLOT_COUNT_DEFAULT);
  const frameSabSlotBytes = parsePositiveIntOr(cfg.frameSabSlotBytes, FRAME_SAB_SLOT_BYTES_DEFAULT);
  const sabFrameTransport =
    frameTransportMode === "transfer"
      ? null
      : createSabFrameTransport(frameSabSlotCount, frameSabSlotBytes);
  const frameTransportWire: FrameTransportConfig =
    sabFrameTransport !== null
      ? {
          kind: FRAME_TRANSPORT_SAB_V1,
          version: FRAME_TRANSPORT_VERSION,
          slotCount: sabFrameTransport.slotCount,
          slotBytes: sabFrameTransport.slotBytes,
          control: sabFrameTransport.control,
          data: sabFrameTransport.data,
        }
      : {
          kind: FRAME_TRANSPORT_TRANSFER_V1,
          version: FRAME_TRANSPORT_VERSION,
        };
  const nativeConfig = mergeScreenIntoNativeConfig(