ResolveReferencesToAliasesPass.php

<?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\DependencyInjection\Compiler;

use Symfony\Component\DependencyInjection\Alias;
use Symfony\Component\DependencyInjection\Reference;
use Symfony\Component\DependencyInjection\ContainerBuilder;

/**
 * Replaces all references to aliases with references to the actual service.
 *
 * @author Johannes M. Schmitt <schmittjoh@gmail.com>
 */
class ResolveReferencesToAliasesPass implements CompilerPassInterface {
  private $container;

  /**
   * Processes the ContainerBuilder to replace references to aliases with actual service references.
   *
   * @param ContainerBuilder $container
   */
  public function process(ContainerBuilder $container) {
    $this->container = $container;
    foreach ($container
      ->getDefinitions() as $definition) {
      if ($definition
        ->isSynthetic() || $definition
        ->isAbstract()) {
        continue;
      }
      $definition
        ->setArguments($this
        ->processArguments($definition
        ->getArguments()));
      $definition
        ->setMethodCalls($this
        ->processArguments($definition
        ->getMethodCalls()));
      $definition
        ->setProperties($this
        ->processArguments($definition
        ->getProperties()));
    }
    foreach ($container
      ->getAliases() as $id => $alias) {
      $aliasId = (string) $alias;
      if ($aliasId !== ($defId = $this
        ->getDefinitionId($aliasId))) {
        $container
          ->setAlias($id, new Alias($defId, $alias
          ->isPublic()));
      }
    }
  }

  /**
   * Processes the arguments to replace aliases.
   *
   * @param array $arguments An array of References
   *
   * @return array An array of References
   */
  private function processArguments(array $arguments) {
    foreach ($arguments as $k => $argument) {
      if (is_array($argument)) {
        $arguments[$k] = $this
          ->processArguments($argument);
      }
      elseif ($argument instanceof Reference) {
        $defId = $this
          ->getDefinitionId($id = (string) $argument);
        if ($defId !== $id) {
          $arguments[$k] = new Reference($defId, $argument
            ->getInvalidBehavior(), $argument
            ->isStrict());
        }
      }
    }
    return $arguments;
  }

  /**
   * Resolves an alias into a definition id.
   *
   * @param string $id The definition or alias id to resolve
   *
   * @return string The definition id with aliases resolved
   */
  private function getDefinitionId($id) {
    while ($this->container
      ->hasAlias($id)) {
      $id = (string) $this->container
        ->getAlias($id);
    }
    return $id;
  }

}