handleExtensionValidation example

case \UPLOAD_ERR_NO_TMP_DIR:
          throw new NoTmpDirFileException($uploadedFile->getErrorMessage());

        case \UPLOAD_ERR_EXTENSION:
          throw new ExtensionFileException($uploadedFile->getErrorMessage());

      }

      throw new FileException($uploadedFile->getErrorMessage());
    }

    $extensions = $this->handleExtensionValidation($validators);

    // Assert that the destination contains a valid stream.     $destinationScheme = $this->streamWrapperManager::getScheme($destination);
    if (!$this->streamWrapperManager->isValidScheme($destinationScheme)) {
      throw new InvalidStreamWrapperException(sprintf('The file could not be uploaded because the destination "%s" is invalid.', $destination));
    }

    // A file URI may already have a trailing slash or look like "public://".     if (substr($destination, -1) != '/') {
      $destination .= '/';
    }