original_string: private function getMetaDataStorage()
      {
          $metaStorage = $this->options->metaStorage;
          if ( $metaStorage === null )
          {
              $metaStorage = reset( $this->storageStack )->storage;
              if ( !( $metaStorage instanceof ezcCacheStackMetaDataStorage ) )
              {
                  throw new ezcBaseValueException(
                      'metaStorage',
                      $metaStorage,
                      'ezcCacheStackMetaDataStorage',
                      'top of storage stack'
                  );
              }
          }
          return $metaStorage;
      }
code: private function getMetaDataStorage()
      {
          $metaStorage = $this->options->metaStorage;
          if ( $metaStorage === null )
          {
              $metaStorage = reset( $this->storageStack )->storage;
              if ( !( $metaStorage instanceof ezcCacheStackMetaDataStorage ) )
              {
                  throw new ezcBaseValueException(
                      'metaStorage',
                      $metaStorage,
                      'ezcCacheStackMetaDataStorage',
                      'top of storage stack'
                  );
              }
          }
          return $metaStorage;
      }
code_tokens: private function getMetaDataStorage ( ) { $ metaStorage = $ this -> options -> metaStorage ; if ( $ metaStorage === null ) { $ metaStorage = reset ( $ this -> storageStack ) -> storage ; if ( ! ( $ metaStorage instanceof ezcCacheStackMetaDataStorage ) ) { throw new ezcBaseValueException ( 'metaStorage' , $ metaStorage , 'ezcCacheStackMetaDataStorage' , 'top of storage stack' ) ; } } return $ metaStorage ; }
docstring: Returns the meta data storage to be used.
  
  Determines the meta data storage to be used by the stack and returns it.
  
  @return ezcCacheStackMetaData
docstring_tokens: Returns the meta data storage to be used .