docs: function(entry) {
          var result;
          if (entry) {
              if (successCallback) {
                  // create appropriate Entry object
                  result = (entry.isDirectory) ? new DirectoryEntry(entry.name, entry.fullPath) : new FileEntry(entry.name, entry.fullPath);
                  successCallback(result);
              }
          }
          else {
              // no Entry object returned
              fail(FileError.NOT_FOUND_ERR);
          }
      }