public function isWritable()
{
if (!$this->resource) {
return false;
}
$meta = stream_get_meta_data($this->resource);
$mode = $meta['mode'];
return strstr($mode, 'x') || strstr($mode, 'w') || strstr($mode, 'c') || strstr($mode, 'a') || strstr($mode, '+');
}