gistfile1.php

<?php

/**
 * @file
 * Contains \Drupal\Core\Plugin\ContainerFactoryPluginBase.
 */
namespace Drupal\Core\Plugin;

use Drupal\Core\Plugin\ContextAwarePluginBase;

use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Defines a base plugin that can pull it's dependencies from the container.
 */
class ContainerFactoryPluginBase extends ContextAwarePluginBase {

  /**
   * Creates an instance of the plugin.
   *
   * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
   *   The container to pull out services used in the plugin.
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param array $plugin_definition
   *   The plugin implementation definition.
   *
   * @return static
   *   Returns an instance of this plugin.
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, array $plugin_definition) {
    $plugin = new static($configuration, $plugin_id, $plugin_definition);
    $plugin->processServices($container, $configuartion, $plugin_id, $plugin_definition);
    return $plugin;
  }

  public function processServices(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    if (isset($plugin_definition['services']) {
      foreach ($plugin_definition['services'] as $setter => $service_id) {
        if (empty($configuration['services'][$service_id]) && $container->has($service_id)) {
          $plugin->$setter($container->get($service_id));
        }
        elseif (!empty($configuration['services'][$service_id])) {
          $plugin->$setter($configuration['services'][$service_id]);
        }
      }
    }
  }

}