ManyToOne.php

<?php

namespace Drupal\views\Plugin\views\filter;

use Drupal\Core\Form\FormStateInterface;
use Drupal\views\ViewExecutable;
use Drupal\views\Plugin\views\display\DisplayPluginBase;
use Drupal\views\ManyToOneHelper;

/**
 * Complex filter to handle filtering for many to one relationships,
 * such as terms (many terms per node) or roles (many roles per user).
 *
 * The construct method needs to be overridden to provide a list of options;
 * alternately, the valueForm and adminSummary methods need to be overridden
 * to provide something that isn't just a select list.
 *
 * @ingroup views_filter_handlers
 *
 * @ViewsFilter("many_to_one")
 */
class ManyToOne extends InOperator {
    
    /**
     * @var \Drupal\views\ManyToOneHelper
     *
     * Stores the Helper object which handles the many_to_one complexity.
     */
    public $helper = NULL;
    
    /**
     * {@inheritdoc}
     */
    public function init(ViewExecutable $view, DisplayPluginBase $display, array &$options = NULL) {
        parent::init($view, $display, $options);
        $this->helper = new ManyToOneHelper($this);
    }
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['operator']['default'] = 'or';
        $options['value']['default'] = [];
        if (isset($this->helper)) {
            $this->helper
                ->defineOptions($options);
        }
        else {
            $helper = new ManyToOneHelper($this);
            $helper->defineOptions($options);
        }
        return $options;
    }
    public function operators() {
        $operators = [
            'or' => [
                'title' => $this->t('Is one of'),
                'short' => $this->t('or'),
                'short_single' => $this->t('='),
                'method' => 'opHelper',
                'values' => 1,
                'ensure_my_table' => 'helper',
            ],
            'and' => [
                'title' => $this->t('Is all of'),
                'short' => $this->t('and'),
                'short_single' => $this->t('='),
                'method' => 'opHelper',
                'values' => 1,
                'ensure_my_table' => 'helper',
            ],
            'not' => [
                'title' => $this->t('Is none of'),
                'short' => $this->t('not'),
                'short_single' => $this->t('<>'),
                'method' => 'opHelper',
                'values' => 1,
                'ensure_my_table' => 'helper',
            ],
        ];
        // if the definition allows for the empty operator, add it.
        if (!empty($this->definition['allow empty'])) {
            $operators += [
                'empty' => [
                    'title' => $this->t('Is empty (NULL)'),
                    'method' => 'opEmpty',
                    'short' => $this->t('empty'),
                    'values' => 0,
                ],
                'not empty' => [
                    'title' => $this->t('Is not empty (NOT NULL)'),
                    'method' => 'opEmpty',
                    'short' => $this->t('not empty'),
                    'values' => 0,
                ],
            ];
        }
        return $operators;
    }
    protected $valueFormType = 'select';
    protected function valueForm(&$form, FormStateInterface $form_state) {
        parent::valueForm($form, $form_state);
        if (!$form_state->get('exposed')) {
            $this->helper
                ->buildOptionsForm($form, $form_state);
        }
    }
    
    /**
     * Override ensureMyTable so we can control how this joins in.
     * The operator actually has influence over joining.
     */
    public function ensureMyTable() {
        // Defer to helper if the operator specifies it.
        $info = $this->operators();
        if (isset($info[$this->operator]['ensure_my_table']) && $info[$this->operator]['ensure_my_table'] == 'helper') {
            return $this->helper
                ->ensureMyTable();
        }
        return parent::ensureMyTable();
    }
    protected function opHelper() {
        if (empty($this->value)) {
            return;
        }
        // Form API returns unchecked options in the form of option_id => 0. This
        // breaks the generated query for "is all of" filters so we remove them.
        $this->value = array_filter($this->value, 'static::arrayFilterZero');
        $this->helper
            ->addFilter();
    }

}