Method acquire

ch6-mutex/mutex.js:14–20

()

  }

  acquire() {
    if (compareExchange(this.shared, this.index, UNLOCKED, LOCKED) === UNLOCKED) {
      return;
    }
    wait(this.shared, this.index, LOCKED);
    this.acquire();
  }

  release() {
    if (compareExchange(this.shared, this.index, LOCKED, UNLOCKED) !== LOCKED) {