Issue #3359708 by DieterHolvoet: Add views integration

config/schema/taxonomy_enum.filter.schema.yml

+views.filter.taxonomy_enum_reference:
+  type: views.filter.in_operator
+  label: 'Taxonomy term enum'

src/Migration.php

@@ -58,6 +58,7 @@ class Migration {
     $this->entityFieldManager->clearCachedFieldDefinitions();
 
     $fieldStorageConfig->set('type', 'taxonomy_enum');
+    $fieldStorageConfig->set('module', 'taxonomy_enum');
     $fieldStorageConfig->save(TRUE);
 
     FieldStorageConfig::loadByName($entityTypeId, $fieldName)->calculateDependencies()->save();

src/Plugin/views/filter/TaxonomyEnumReference.php

+<?php
+
+namespace Drupal\taxonomy_enum\Plugin\views\filter;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\taxonomy\TermInterface;
+use Drupal\views\Plugin\views\filter\ManyToOne;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Filters a view by entity references.
+ *
+ * @ingroup views_filter_handlers
+ *
+ * @ViewsFilter("taxonomy_enum_reference")
+ */
+class TaxonomyEnumReference extends ManyToOne {
+
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->entityTypeManager = $container->get('entity_type.manager');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query() {
+    $machineNames = $this->value;
+    $termIds = $this->entityTypeManager
+      ->getStorage('taxonomy_term')
+      ->getQuery()
+      ->condition('vid', $this->options['vid'])
+      ->condition('machine_name', $this->value, 'IN')
+      ->accessCheck(FALSE)
+      ->execute();
+
+    $this->value = array_values($termIds);
+    parent::query();
+    $this->value = $machineNames;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getValueOptions() {
+    if ($this->valueOptions !== NULL && $this->valueOptions !== []) {
+      return $this->valueOptions;
+    }
+
+    if (!$vid = $this->options['vid']) {
+      $this->valueOptions = [];
+      return;
+    }
+
+    $vocabulary = $this->entityTypeManager->getStorage('taxonomy_vocabulary')->load($vid);
+    $enumName = $vocabulary->getThirdPartySetting('taxonomy_enum', 'enum_name');
+
+    if (!enum_exists($enumName) || !method_exists($enumName, 'from')) {
+      $this->valueOptions = [];
+      return;
+    }
+
+    $termStorage = $this->entityTypeManager
+      ->getStorage('taxonomy_term');
+    $termIds = $termStorage->getQuery()
+      ->condition('vid', $vid)
+      ->accessCheck(FALSE)
+      ->execute();
+    $terms = $termStorage->loadMultiple($termIds);
+
+    $this->valueOptions = array_reduce(
+      $terms,
+      function (?array $options, TermInterface $term) {
+        $options[$term->get('machine_name')->value] = $term->label();
+        return $options;
+      },
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function hasExtraOptions() {
+    return TRUE;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildExtraOptionsForm(&$form, FormStateInterface $form_state) {
+    $form['vid'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Vocabulary'),
+      '#options' => array_map(
+        function ($vocabulary) {
+          return $vocabulary->label();
+        },
+        Vocabulary::loadMultiple(),
+      ),
+      '#default_value' => $this->options['vid'],
+    ];
+  }
+
+}

taxonomy_enum.module

@@ -7,9 +7,11 @@
 
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Access\AccessResultInterface;
+use Drupal\Core\Entity\ContentEntityTypeInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Render\Markup;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\field\FieldStorageConfigInterface;
 use Drupal\taxonomy\VocabularyInterface;
 use Drupal\taxonomy_enum\Exception\InvalidEnumException;
 use Drupal\Core\Routing\RouteMatchInterface;
@@ -265,3 +267,91 @@ function taxonomy_enum_form_taxonomy_term_form_alter(array &$form, FormStateInte
 
   $form['machine_name']['#disabled'] = TRUE;
 }
+
+/**
+ * Implements hook_field_views_data().
+ *
+ * @see core_field_views_data()
+ */
+function taxonomy_enum_field_views_data(FieldStorageConfigInterface $field_storage): array {
+  $data = views_field_default_views_data($field_storage);
+
+  // The code below only deals with the Taxonomy enum field type.
+  if ($field_storage->getType() != 'taxonomy_enum') {
+    return $data;
+  }
+
+  $entity_type_manager = \Drupal::entityTypeManager();
+  $entity_type_id = $field_storage->getTargetEntityTypeId();
+  /** @var \Drupal\Core\Entity\Sql\DefaultTableMapping $table_mapping */
+  $table_mapping = $entity_type_manager->getStorage($entity_type_id)->getTableMapping();
+
+  foreach ($data as $table_name => $table_data) {
+    // Add a relationship to the target entity type.
+    $target_entity_type_id = $field_storage->getSetting('target_type');
+    $target_entity_type = $entity_type_manager->getDefinition($target_entity_type_id);
+    $entity_type_id = $field_storage->getTargetEntityTypeId();
+    $entity_type = $entity_type_manager->getDefinition($entity_type_id);
+    $target_base_table = $target_entity_type->getDataTable() ?: $target_entity_type->getBaseTable();
+    $field_name = $field_storage->getName();
+
+    if ($target_entity_type instanceof ContentEntityTypeInterface) {
+      foreach ($table_data as $table_field_name => $table_field_data) {
+        if (isset($table_field_data['filter']) && $table_field_name != 'delta') {
+          // Create separate views data to allow use of the entity_reference
+          // filter. Numeric filter should still be available for use.
+          $entity_reference = $data[$table_name][$table_field_name];
+          $entity_reference['filter']['id'] = 'taxonomy_enum_reference';
+          $entity_reference['title'] = $entity_reference['title'] . ' ' . t('as an Enum filter');
+          $data[$table_name][$table_field_name . '_enum'] = $entity_reference;
+        }
+      }
+
+      // Provide a relationship for the entity type with the entity reference
+      // field.
+      $args = [
+        '@label' => $target_entity_type->getLabel(),
+        '@field_name' => $field_name,
+      ];
+      $data[$table_name][$field_name]['relationship'] = [
+        'title' => t('@label referenced from @field_name', $args),
+        'label' => t('@field_name: @label', $args),
+        'group' => $entity_type->getLabel(),
+        'help' => t('Appears in: @bundles.', ['@bundles' => implode(', ', $field_storage->getBundles())]),
+        'id' => 'standard',
+        'base' => $target_base_table,
+        'entity type' => $target_entity_type_id,
+        'base field' => $target_entity_type->getKey('id'),
+        'relationship field' => $field_name . '_target_id',
+      ];
+
+      // Provide a reverse relationship for the entity type that is referenced by
+      // the field.
+      $args['@entity'] = $entity_type->getLabel();
+      $args['@label'] = $target_entity_type->getSingularLabel();
+      $pseudo_field_name = 'reverse__' . $entity_type_id . '__' . $field_name;
+      $data[$target_base_table][$pseudo_field_name]['relationship'] = [
+        'title' => t('@entity using @field_name', $args),
+        'label' => t('@field_name', ['@field_name' => $field_name]),
+        'group' => $target_entity_type->getLabel(),
+        'help' => t('Relate each @entity with a @field_name set to the @label.', $args),
+        'id' => 'entity_reverse',
+        'base' => $entity_type->getDataTable() ?: $entity_type->getBaseTable(),
+        'entity_type' => $entity_type_id,
+        'base field' => $entity_type->getKey('id'),
+        'field_name' => $field_name,
+        'field table' => $table_mapping->getDedicatedDataTableName($field_storage),
+        'field field' => $field_name . '_target_id',
+        'join_extra' => [
+          [
+            'field' => 'deleted',
+            'value' => 0,
+            'numeric' => TRUE,
+          ],
+        ],
+      ];
+    }
+  }
+
+  return $data;
+}