--- /dev/null
+<?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;
+ }
+ $this->helper->addFilter();
+ }
+
+}