/**
  * Returns a list of mappings like array('some/path.txt' => 'file PHID');
  */
 private function getFragmentMappings(PhragmentFragment $current, $base_path, $snapshot)
 {
     $mappings = $current->getFragmentMappings($this->getRequest()->getUser(), $base_path);
     $result = array();
     foreach ($mappings as $path => $fragment) {
         $version = $this->getVersion($fragment, $snapshot);
         if ($version !== null) {
             $result[$path] = $version->getFilePHID();
         }
     }
     return $result;
 }