<?php
  
  /*
   * This file is part of the Symfony package.
   *
   * (c) Fabien Potencier <fabien@symfony.com>
   *
   * For the full copyright and license information, please view the LICENSE
   * file that was distributed with this source code.
   */
  
  namespace Symfony\Component\Translation\Loader;
  
  use Symfony\Component\Translation\Exception\InvalidResourceException;
  use Symfony\Component\Translation\Exception\LogicException;
  use Symfony\Component\Yaml\Exception\ParseException;
  use Symfony\Component\Yaml\Parser as YamlParser;
  use Symfony\Component\Yaml\Yaml;
  
  /**
   * YamlFileLoader loads translations from Yaml files.
   *
   * @author Fabien Potencier <fabien@symfony.com>
   */
  class YamlFileLoader extends FileLoader
  {
      private $yamlParser;
  
      /**
       * {@inheritdoc}
       */
      protected function loadResource(string $resource)
      {
          if (null === $this->yamlParser) {
              if (!class_exists(\Symfony\Component\Yaml\Parser::class)) {
                  throw new LogicException('Loading translations from the YAML format requires the Symfony Yaml component.');
              }
  
              $this->yamlParser = new YamlParser();
          }
  
          try {
              $messages = $this->yamlParser->parseFile($resource, Yaml::PARSE_CONSTANT);
          } catch (ParseException $e) {
              throw new InvalidResourceException(sprintf('The file "%s" does not contain valid YAML: ', $resource).$e->getMessage(), 0, $e);
          }
  
          if (null !== $messages && !\is_array($messages)) {
              throw new InvalidResourceException(sprintf('Unable to load file "%s".', $resource));
          }
  
          return $messages ?: [];
      }
  }