Function start

packages/node/src/backend/nodeBackendInline.ts:528–602

()

  const backend: RuntimeBackend = {
    async start(): Promise<void> {
      if (disposed) throw new Error("NodeBackend(inline): disposed");
      if (fatal !== null) throw fatal;
      if (started) return;
      if (startDef !== null) {
        await startDef.promise;
        return;
      }

      startDef = deferred<void>();
      startSettled = false;
      stopRequested = false;

      try {
        if (initConfigResolved === null) {
          const resolvedEmojiWidthPolicy = await resolveBackendEmojiWidthPolicy(
            cfg.emojiWidthPolicy,
            nativeConfig,
          );
          const nativeWidthPolicy = applyEmojiWidthPolicy(resolvedEmojiWidthPolicy);
          initConfigResolved = {
            ...initConfigBase,
            widthPolicy: nativeWidthPolicy,
          };
        } else {
          const widthPolicy = initConfigResolved[WIDTH_POLICY_KEY];
          if (typeof widthPolicy === "number") {
            setTextMeasureEmojiPolicy(widthPolicy === 0 ? "narrow" : "wide");
          }
        }

        const api = await ensureNativeLoaded();
        let id = 0;
        try {
          id = api.engineCreate(initConfigResolved);
        } catch (err) {
          throw new Error(`engine_create threw: ${safeDetail(err)}`);
        }
        if (!Number.isInteger(id) || id <= 0) {
          throw new Error(`engine_create failed: code=${String(id)}`);
        }
        engineId = id;
        started = true;
        if (frameAudit.enabled) {
          frameAudit.emit("engine.ready", {
            engineId: id,
            executionMode: "inline",
            fpsCap,
            maxEventBytes,
          });
        }
        cachedCaps = null;
        eventQueue = [];
        eventPool = [];
        for (let i = 0; i < EVENT_POOL_SIZE; i++) {
          eventPool.push(new ArrayBuffer(maxEventBytes));
        }
        discardBuffer = new ArrayBuffer(maxEventBytes);