LatestRevision.php

<?php

namespace Drupal\views\Plugin\views\filter;

use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\views\Plugin\ViewsHandlerManager;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Filter to show only the latest revision of an entity.
 *
 * @ingroup views_filter_handlers
 *
 * @ViewsFilter("latest_revision")
 */
class LatestRevision extends FilterPluginBase implements ContainerFactoryPluginInterface {
    
    /**
     * Entity Type Manager service.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * Views Handler Plugin Manager.
     *
     * @var \Drupal\views\Plugin\ViewsHandlerManager
     */
    protected $joinHandler;
    
    /**
     * Constructs a new LatestRevision.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   Entity Type Manager Service.
     * @param \Drupal\views\Plugin\ViewsHandlerManager $join_handler
     *   Views Handler Plugin Manager.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager, ViewsHandlerManager $join_handler) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->entityTypeManager = $entity_type_manager;
        $this->joinHandler = $join_handler;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('entity_type.manager'), $container->get('plugin.manager.views.join'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function adminSummary() {
    }
    
    /**
     * {@inheritdoc}
     */
    protected function operatorForm(&$form, FormStateInterface $form_state) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function canExpose() {
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        
        /** @var \Drupal\views\Plugin\views\query\Sql $query */
        $query = $this->query;
        $query_base_table = $this->relationship ?: $this->view->storage
            ->get('base_table');
        $entity_type = $this->entityTypeManager
            ->getDefinition($this->getEntityType());
        $keys = $entity_type->getKeys();
        $definition = [
            'table' => $query_base_table,
            'type' => 'LEFT',
            'field' => $keys['id'],
            'left_table' => $query_base_table,
            'left_field' => $keys['id'],
            'extra' => [
                [
                    'left_field' => $keys['revision'],
                    'field' => $keys['revision'],
                    'operator' => '>',
                ],
            ],
        ];
        $join = $this->joinHandler
            ->createInstance('standard', $definition);
        $join_table_alias = $query->addTable($query_base_table, $this->relationship, $join);
        $query->addWhere($this->options['group'], "{$join_table_alias}.{$keys['id']}", NULL, 'IS NULL');
    }

}