MatthiasMullie\Scrapbook\Buffered\Utils\Transaction::cas PHP Method

    public function cas($token, $key, $value, $expire = 0)
    {
        $originalValue = isset($this->tokens[$token]) ? $this->tokens[$token] : null;
        // value is no longer the same as what we used for token
        if (serialize($this->get($key)) !== $originalValue) {
            return false;
        }
        // "CAS" value to local cache/memory
        $success = $this->local->set($key, $value, $expire);
        if ($success === false) {
            return false;
        }
        // only schedule the CAS to be performed on real cache if it was OK on
        // local cache
        $this->defer->cas($originalValue, $key, $value, $expire);
        return true;
    }

 /**
  * {@inheritdoc}
  */
 public function cas($token, $key, $value, $expire = 0)
 {
     $result = $this->transaction->cas($token, $key, $value, $expire);
     $this->transaction->commit();
     return $result;
 }