nstdlib-nightly/lib/internal/watchdog.mjs

Node.js standard library converted to runtime-agnostic ES modules.

// Source: https://github.com/nodejs/node/blob/65eff1eb/lib/internal/watchdog.js

import { TraceSigintWatchdog } from "nstdlib/stub/binding/watchdog";

class SigintWatchdog extends TraceSigintWatchdog {
  _started = false;
  _effective = false;
  _onNewListener = (eve) => {
    if (eve === "SIGINT" && this._effective) {
      super.stop();
      this._effective = false;
    }
  };
  _onRemoveListener = (eve) => {
    if (
      eve === "SIGINT" &&
      process.listenerCount("SIGINT") === 0 &&
      !this._effective
    ) {
      super.start();
      this._effective = true;
    }
  };

  start() {
    if (this._started) {
      return;
    }
    this._started = true;
    // Prepend sigint newListener to remove stop watchdog before signal wrap
    // been activated. Also make sigint removeListener been ran after signal
    // wrap been stopped.
    process.prependListener("newListener", this._onNewListener);
    process.addListener("removeListener", this._onRemoveListener);

    if (process.listenerCount("SIGINT") === 0) {
      super.start();
      this._effective = true;
    }
  }

  stop() {
    if (!this._started) {
      return;
    }
    this._started = false;
    process.removeListener("newListener", this._onNewListener);
    process.removeListener("removeListener", this._onRemoveListener);

    if (this._effective) {
      super.stop();
      this._effective = false;
    }
  }
}

export { SigintWatchdog };