class FileValidator

class FileValidator implements FileValidatorInterface {
    
    /**
     * Creates a new FileValidator.
     *
     * @param \Symfony\Component\Validator\Validator\ValidatorInterface $validator
     *   The validator.
     * @param \Drupal\Core\Validation\ConstraintManager $constraintManager
     *   The constraint factory.
     * @param \Symfony\Contracts\EventDispatcher\EventDispatcherInterface $eventDispatcher
     *   The event dispatcher.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
     *   The module handler.
     */
    public function __construct(ValidatorInterface $validator, ConstraintManager $constraintManager, EventDispatcherInterface $eventDispatcher, ModuleHandlerInterface $moduleHandler) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function validate(FileInterface $file, array $validators) : ConstraintViolationListInterface {
        $constraints = [];
        $errors = [];
        foreach ($validators as $validator => $options) {
            if (function_exists($validator)) {
                @trigger_error('Support for file validation function ' . $validator . '() is deprecated in drupal:10.2.0 and will be removed in drupal:11.0.0. Use Symfony Constraints instead. See https://www.drupal.org/node/3363700', E_USER_DEPRECATED);
                if (!is_array($options)) {
                    $options = [
                        $options,
                    ];
                }
                array_unshift($options, $file);
                // Call the validation function.
                // Options are a list of function args.
                $errors = array_merge($errors, call_user_func_array($validator, $options));
            }
            else {
                // Create the constraint.
                // Options are an associative array of constraint properties and values.
                try {
                    $constraints[] = $this->constraintManager
                        ->create($validator, $options);
                } catch (PluginNotFoundException) {
                    @trigger_error(sprintf('Passing invalid constraint plugin ID "%s" in the list of $validators to Drupal\\file\\Validation\\FileValidator::validate() is deprecated in drupal:10.2.0 and will throw an exception in drupal:11.0.0. See https://www.drupal.org/node/3363700', $validator), E_USER_DEPRECATED);
                }
            }
        }
        // Call legacy hook implementations.
        $errors = array_merge($errors, $this->moduleHandler
            ->invokeAllDeprecated('Use file validation events instead. See https://www.drupal.org/node/3363700', 'file_validate', [
            $file,
        ]));
        $violations = new ConstraintViolationList();
        // Convert legacy errors to violations.
        $translator = new DrupalTranslator();
        foreach ($errors as $error) {
            $violation = new ConstraintViolation($translator->trans($error), $error, [], $file, '', NULL);
            $violations->add($violation);
        }
        // Get the typed data.
        $fileTypedData = $file->getTypedData();
        $violations->addAll($this->validator
            ->validate($fileTypedData, $constraints));
        $this->eventDispatcher
            ->dispatch(new FileValidationEvent($file, $violations));
        // Always check the insecure upload constraint.
        if (count($violations) === 0) {
            $insecureUploadConstraint = $this->constraintManager
                ->create('FileExtensionSecure', []);
            $violations = $this->validator
                ->validate($fileTypedData, $insecureUploadConstraint);
        }
        return $violations;
    }

}