/**
* Get a file in MongoGridFS
* The result is cached to save resource.
*
* @return \MongoGridFS
*/
public function getDocument()
{
if (!isset($this->cache['document'])) {
$this->cache['document'] = $this->fs->findOne(array('filename' => $this->getResolvedPath()));
}
return $this->cache['document'];
}