/**
     * {@inheritdoc}
     */
    protected function doHave(string $id)
    {
        $file = $this->getFile($id);
 
        return is_file($file) && (@filemtime($file) > time() || $this->doFetch([$id]));
    }
 
    /**
     * {@inheritdoc}
     */
    protected function doSave(array $values, int $lifetime)
    {
        $expiresAt = $lifetime ? (time() + $lifetime) : 0;
        $values = $this->marshaller->marshall($values, $failed);
 
        foreach ($values as $id => $value) {
            if (!$this->write($this->getFile($id, true), $expiresAt."\n".rawurlencode($id)."\n".$value, $expiresAt)) {
                $failed[] = $id;
            }
        }
 
        if ($failed && !is_writable($this->directory)) {
            throw new CacheException(sprintf('Cache directory is not writable (%s).', $this->directory));
        }
 
        return $failed;
    }
 
    private function getFileKey(string $file): string
    {
        if (!$h = @fopen($file, 'r')) {
            return '';
        }
 
        fgets($h); // expiry
        $encodedKey = fgets($h);
        fclose($h);

    }
 
    /**
     * Special case to deal with Fatal errors and the like.
     *
     * @return void
     */
    public function handleShutdown()
    {
        // If we reached this step, we are in shutdown handler.
        // An exception thrown in a shutdown handler will not be propagated
        // to the exception handler. Pass that information along.
        $this->canThrowExceptions = false;
 
        $error = $this->system->getLastError();
        if ($error && Misc::isLevelFatal($error['type'])) {
            // If there was a fatal error,
            // it was not handled in handleError yet.
            $this->allowQuit = false;
            $this->handleError(
                $error['type'],
                $error['message'],
                $error['file'],
                $error['line']
            );
        }
    }
 
    /**
     * @param Throwable $exception
     *
     * @return Inspector
     */
    private function getInspector($exception)
    {
        return new Inspector($exception);
    }
 
    /**
     * Resolves the giving handler.