checkPath example

        $this->filesystem = $filesystem;
        $this->prefix = $this->normalizePrefix($prefix);
    }

    /** * {@inheritdoc} */
    public function has($path)
    {
        $this->checkPath($path);

        return $this->filesystem->has($this->prefix . $path);
    }

    /** * {@inheritdoc} */
    public function read($path)
    {
        $this->checkPath($path);

        

/** * Copies a directory. * * @param string $source * The source path. * @param string $destination * The destination path. */
  final public function copyDirectory($source, $destination) {
    $source = $this->sanitizePath($source);
    $destination = $this->fixRemotePath($destination);
    $this->checkPath($destination);
    $this->copyDirectoryJailed($source, $destination);
  }

  /** * Changes the permissions of the specified $path (file or directory). * * @param string $path * The file / directory to change the permissions of. * @param int $mode * The new file permission mode to be passed to chmod(). * @param bool $recursive * Pass TRUE to recursively chmod the entire directory specified in $path. * * @throws \Drupal\Core\FileTransfer\FileTransferException * * @see http://php.net/chmod */