class EntityFieldManager

class EntityFieldManager implements EntityFieldManagerInterface {
    use UseCacheBackendTrait;
    use StringTranslationTrait;
    
    /**
     * Extra fields info, if initialized.
     *
     * The fields are keyed by entity type, bundle, type ('form' or 'display'),
     * and the extra field name.
     *
     * @var array[][][][]|null
     */
    protected ?array $extraFields = NULL;
    
    /**
     * Static cache of base field definitions.
     *
     * @var array
     */
    protected $baseFieldDefinitions;
    
    /**
     * Static cache of field definitions per bundle and entity type.
     *
     * @var array
     */
    protected $fieldDefinitions;
    
    /**
     * Static cache of field storage definitions per entity type.
     *
     * Elements of the array:
     *  - $entity_type_id: \Drupal\Core\Field\BaseFieldDefinition[]
     *
     * @var array
     */
    protected $fieldStorageDefinitions;
    
    /**
     * Static cache of active field storage definitions per entity type.
     *
     * @var array
     */
    protected $activeFieldStorageDefinitions;
    
    /**
     * An array of lightweight maps of fields, keyed by entity type.
     *
     * Each value is an array whose keys are field names and whose value is an
     * array with two entries:
     *   - type: The field type.
     *   - bundles: The bundles in which the field appears.
     *
     * @var array
     */
    protected $fieldMap = [];
    
    /**
     * An array of lightweight maps of fields, keyed by field type.
     *
     * Each value is an array whose key are entity types including arrays in the
     * same form as $fieldMap. It helps access the mapping between types and
     * fields by the field type.
     *
     * @var array
     */
    protected $fieldMapByFieldType = [];
    
    /**
     * The typed data manager.
     *
     * @var \Drupal\Core\TypedData\TypedDataManagerInterface
     */
    protected $typedDataManager;
    
    /**
     * The language manager.
     *
     * @var \Drupal\Core\Language\LanguageManagerInterface
     */
    protected $languageManager;
    
    /**
     * The key-value factory.
     *
     * @var \Drupal\Core\KeyValueStore\KeyValueFactoryInterface
     */
    protected $keyValueFactory;
    
    /**
     * The module handler.
     *
     * @var \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected $moduleHandler;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The entity type bundle info.
     *
     * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
     */
    protected $entityTypeBundleInfo;
    
    /**
     * The entity display repository.
     *
     * @var \Drupal\Core\Entity\EntityDisplayRepositoryInterface
     */
    protected $entityDisplayRepository;
    
    /**
     * The entity last installed schema repository.
     *
     * @var \Drupal\Core\Entity\EntityLastInstalledSchemaRepositoryInterface
     */
    protected $entityLastInstalledSchemaRepository;
    
    /**
     * Constructs a new EntityFieldManager.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
     *   The entity type bundle info.
     * @param \Drupal\Core\Entity\EntityDisplayRepositoryInterface $entity_display_repository
     *   The entity display repository.
     * @param \Drupal\Core\TypedData\TypedDataManagerInterface $typed_data_manager
     *   The typed data manager.
     * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
     *   The language manager.
     * @param \Drupal\Core\KeyValueStore\KeyValueFactoryInterface $key_value_factory
     *   The key-value factory.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   The cache backend.
     * @param \Drupal\Core\Entity\EntityLastInstalledSchemaRepositoryInterface $entity_last_installed_schema_repository
     *   The entity last installed schema repository.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityTypeBundleInfoInterface $entity_type_bundle_info, EntityDisplayRepositoryInterface $entity_display_repository, TypedDataManagerInterface $typed_data_manager, LanguageManagerInterface $language_manager, KeyValueFactoryInterface $key_value_factory, ModuleHandlerInterface $module_handler, CacheBackendInterface $cache_backend, EntityLastInstalledSchemaRepositoryInterface $entity_last_installed_schema_repository) {
        $this->entityTypeManager = $entity_type_manager;
        $this->entityTypeBundleInfo = $entity_type_bundle_info;
        $this->entityDisplayRepository = $entity_display_repository;
        $this->typedDataManager = $typed_data_manager;
        $this->languageManager = $language_manager;
        $this->keyValueFactory = $key_value_factory;
        $this->moduleHandler = $module_handler;
        $this->cacheBackend = $cache_backend;
        $this->entityLastInstalledSchemaRepository = $entity_last_installed_schema_repository;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getBaseFieldDefinitions($entity_type_id) {
        // Check the static cache.
        if (!isset($this->baseFieldDefinitions[$entity_type_id])) {
            // Not prepared, try to load from cache.
            $cid = 'entity_base_field_definitions:' . $entity_type_id . ':' . $this->languageManager
                ->getCurrentLanguage()
                ->getId();
            if ($cache = $this->cacheGet($cid)) {
                $this->baseFieldDefinitions[$entity_type_id] = $cache->data;
            }
            else {
                // Rebuild the definitions and put it into the cache.
                $this->baseFieldDefinitions[$entity_type_id] = $this->buildBaseFieldDefinitions($entity_type_id);
                $this->cacheSet($cid, $this->baseFieldDefinitions[$entity_type_id], Cache::PERMANENT, [
                    'entity_types',
                    'entity_field_info',
                ]);
            }
        }
        return $this->baseFieldDefinitions[$entity_type_id];
    }
    
    /**
     * Builds base field definitions for an entity type.
     *
     * @param string $entity_type_id
     *   The entity type ID. Only entity types that implement
     *   \Drupal\Core\Entity\FieldableEntityInterface are supported.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface[]
     *   An array of field definitions, keyed by field name.
     *
     * @throws \LogicException
     *   Thrown if a config entity type is given or if one of the entity keys is
     *   flagged as translatable.
     */
    protected function buildBaseFieldDefinitions($entity_type_id) {
        
        /** @var \Drupal\Core\Entity\ContentEntityTypeInterface $entity_type */
        $entity_type = $this->entityTypeManager
            ->getDefinition($entity_type_id);
        $class = $entity_type->getClass();
        
        /** @var string[] $keys */
        $keys = array_filter($entity_type->getKeys());
        // Fail with an exception for non-fieldable entity types.
        if (!$entity_type->entityClassImplements(FieldableEntityInterface::class)) {
            throw new \LogicException("Getting the base fields is not supported for entity type {$entity_type->getLabel()}.");
        }
        // Retrieve base field definitions.
        
        /** @var \Drupal\Core\Field\FieldStorageDefinitionInterface[] $base_field_definitions */
        $base_field_definitions = $class::baseFieldDefinitions($entity_type);
        // Make sure translatable entity types are correctly defined.
        if ($entity_type->isTranslatable()) {
            // The langcode field should always be translatable if the entity type is.
            if (isset($keys['langcode']) && isset($base_field_definitions[$keys['langcode']])) {
                $base_field_definitions[$keys['langcode']]->setTranslatable(TRUE);
            }
            // A default_langcode field should always be defined.
            if (!isset($base_field_definitions[$keys['default_langcode']])) {
                $base_field_definitions[$keys['default_langcode']] = BaseFieldDefinition::create('boolean')->setLabel($this->t('Default translation'))
                    ->setDescription($this->t('A flag indicating whether this is the default translation.'))
                    ->setTranslatable(TRUE)
                    ->setRevisionable(TRUE)
                    ->setDefaultValue(TRUE);
            }
        }
        // Make sure that revisionable entity types are correctly defined.
        if ($entity_type->isRevisionable()) {
            $field_name = $entity_type->getRevisionMetadataKey('revision_default');
            $base_field_definitions[$field_name] = BaseFieldDefinition::create('boolean')->setLabel($this->t('Default revision'))
                ->setDescription($this->t('A flag indicating whether this was a default revision when it was saved.'))
                ->setStorageRequired(TRUE)
                ->setInternal(TRUE)
                ->setTranslatable(FALSE)
                ->setRevisionable(TRUE);
        }
        // Make sure that revisionable and translatable entity types are correctly
        // defined.
        if ($entity_type->isRevisionable() && $entity_type->isTranslatable()) {
            // The 'revision_translation_affected' field should always be defined.
            // This field has been added unconditionally in Drupal 8.4.0 and it is
            // overriding any pre-existing definition on purpose so that any
            // differences are immediately available in the status report.
            $base_field_definitions[$keys['revision_translation_affected']] = BaseFieldDefinition::create('boolean')->setLabel($this->t('Revision translation affected'))
                ->setDescription($this->t('Indicates if the last edit of a translation belongs to current revision.'))
                ->setReadOnly(TRUE)
                ->setRevisionable(TRUE)
                ->setTranslatable(TRUE);
        }
        // Assign base field definitions the entity type provider.
        $provider = $entity_type->getProvider();
        foreach ($base_field_definitions as $definition) {
            // @todo Remove this check once FieldDefinitionInterface exposes a proper
            //   provider setter. See https://www.drupal.org/node/2346329.
            if ($definition instanceof BaseFieldDefinition) {
                $definition->setProvider($provider);
            }
        }
        // Retrieve base field definitions from modules.
        $this->moduleHandler
            ->invokeAllWith('entity_base_field_info', function (callable $hook, string $module) use (&$base_field_definitions, $entity_type) {
            $module_definitions = $hook($entity_type) ?? [];
            // Ensure the provider key actually matches the name of the provider
            // defining the field.
            foreach ($module_definitions as $field_name => $definition) {
                // @todo Remove this check once FieldDefinitionInterface exposes a
                //   proper provider setter. See https://www.drupal.org/node/2346329.
                if ($definition instanceof BaseFieldDefinition && $definition->getProvider() == NULL) {
                    $definition->setProvider($module);
                }
                $base_field_definitions[$field_name] = $definition;
            }
        });
        // Automatically set the field name, target entity type and bundle
        // for non-configurable fields.
        foreach ($base_field_definitions as $field_name => $base_field_definition) {
            if ($base_field_definition instanceof BaseFieldDefinition) {
                $base_field_definition->setName($field_name);
                $base_field_definition->setTargetEntityTypeId($entity_type_id);
                $base_field_definition->setTargetBundle(NULL);
            }
        }
        // Invoke alter hook.
        $this->moduleHandler
            ->alter('entity_base_field_info', $base_field_definitions, $entity_type);
        // Ensure defined entity keys are there and have proper revisionable and
        // translatable values.
        foreach (array_intersect_key($keys, array_flip([
            'id',
            'revision',
            'uuid',
            'bundle',
        ])) as $key => $field_name) {
            if (!isset($base_field_definitions[$field_name])) {
                throw new \LogicException("The {$field_name} field definition does not exist and it is used as {$key} entity key.");
            }
            if ($base_field_definitions[$field_name]->isRevisionable()) {
                throw new \LogicException("The {$base_field_definitions[$field_name]->getLabel()} field cannot be revisionable as it is used as {$key} entity key.");
            }
            if ($base_field_definitions[$field_name]->isTranslatable()) {
                throw new \LogicException("The {$base_field_definitions[$field_name]->getLabel()} field cannot be translatable as it is used as {$key} entity key.");
            }
        }
        // Make sure translatable entity types define the "langcode" field properly.
        if ($entity_type->isTranslatable() && (!isset($keys['langcode']) || !isset($base_field_definitions[$keys['langcode']]) || !$base_field_definitions[$keys['langcode']]->isTranslatable())) {
            throw new \LogicException("The {$entity_type->getLabel()} entity type cannot be translatable as it does not define a translatable \"langcode\" field.");
        }
        return $base_field_definitions;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFieldDefinitions($entity_type_id, $bundle) {
        $langcode = $this->languageManager
            ->getCurrentLanguage()
            ->getId();
        if (!isset($this->fieldDefinitions[$entity_type_id][$bundle][$langcode])) {
            $base_field_definitions = $this->getBaseFieldDefinitions($entity_type_id);
            // Not prepared, try to load from cache.
            $cid = 'entity_bundle_field_definitions:' . $entity_type_id . ':' . $bundle . ':' . $langcode;
            if ($cache = $this->cacheGet($cid)) {
                $bundle_field_definitions = $cache->data;
            }
            else {
                // Rebuild the definitions and put it into the cache.
                $bundle_field_definitions = $this->buildBundleFieldDefinitions($entity_type_id, $bundle, $base_field_definitions);
                $this->cacheSet($cid, $bundle_field_definitions, Cache::PERMANENT, [
                    'entity_types',
                    'entity_field_info',
                ]);
            }
            // Field definitions consist of the bundle specific overrides and the
            // base fields, merge them together. Use array_replace() to replace base
            // fields with by bundle overrides and keep them in order, append
            // additional by bundle fields.
            $this->fieldDefinitions[$entity_type_id][$bundle][$langcode] = array_replace($base_field_definitions, $bundle_field_definitions);
        }
        return $this->fieldDefinitions[$entity_type_id][$bundle][$langcode];
    }
    
    /**
     * Builds field definitions for a specific bundle within an entity type.
     *
     * @param string $entity_type_id
     *   The entity type ID. Only entity types that implement
     *   \Drupal\Core\Entity\FieldableEntityInterface are supported.
     * @param string $bundle
     *   The bundle.
     * @param \Drupal\Core\Field\FieldDefinitionInterface[] $base_field_definitions
     *   The list of base field definitions.
     *
     * @return \Drupal\Core\Field\FieldDefinitionInterface[]
     *   An array of bundle field definitions, keyed by field name. Does
     *   not include base fields.
     */
    protected function buildBundleFieldDefinitions($entity_type_id, $bundle, array $base_field_definitions) {
        $entity_type = $this->entityTypeManager
            ->getDefinition($entity_type_id);
        // Use a bundle specific class if one is defined.
        $class = $this->entityTypeManager
            ->getStorage($entity_type_id)
            ->getEntityClass($bundle);
        // Allow the entity class to provide bundle fields and bundle-specific
        // overrides of base fields.
        $bundle_field_definitions = $class::bundleFieldDefinitions($entity_type, $bundle, $base_field_definitions);
        // Load base field overrides from configuration. These take precedence over
        // base field overrides returned above.
        $base_field_override_ids = array_map(function ($field_name) use ($entity_type_id, $bundle) {
            return $entity_type_id . '.' . $bundle . '.' . $field_name;
        }, array_keys($base_field_definitions));
        $base_field_overrides = $this->entityTypeManager
            ->getStorage('base_field_override')
            ->loadMultiple($base_field_override_ids);
        foreach ($base_field_overrides as $base_field_override) {
            
            /** @var \Drupal\Core\Field\Entity\BaseFieldOverride $base_field_override */
            $field_name = $base_field_override->getName();
            $bundle_field_definitions[$field_name] = $base_field_override;
        }
        $provider = $entity_type->getProvider();
        foreach ($bundle_field_definitions as $definition) {
            // @todo Remove this check once FieldDefinitionInterface exposes a proper
            //   provider setter. See https://www.drupal.org/node/2346329.
            if ($definition instanceof BaseFieldDefinition) {
                $definition->setProvider($provider);
            }
        }
        // Retrieve bundle field definitions from modules.
        $this->moduleHandler
            ->invokeAllWith('entity_bundle_field_info', function (callable $hook, string $module) use (&$bundle_field_definitions, $entity_type, $bundle, $base_field_definitions) {
            $module_definitions = $hook($entity_type, $bundle, $base_field_definitions) ?? [];
            // Ensure the provider key actually matches the name of the provider
            // defining the field.
            foreach ($module_definitions as $field_name => $definition) {
                // @todo Remove this check once FieldDefinitionInterface exposes a
                //   proper provider setter. See https://www.drupal.org/node/2346329.
                if ($definition instanceof BaseFieldDefinition) {
                    $definition->setProvider($module);
                }
                $bundle_field_definitions[$field_name] = $definition;
            }
        });
        // Automatically set the field name, target entity type and bundle
        // for non-configurable fields.
        foreach ($bundle_field_definitions as $field_name => $field_definition) {
            if ($field_definition instanceof BaseFieldDefinition) {
                $field_definition->setName($field_name);
                $field_definition->setTargetEntityTypeId($entity_type_id);
            }
            if ($field_definition instanceof BaseFieldDefinition || $field_definition instanceof FieldDefinition) {
                $field_definition->setTargetBundle($bundle);
            }
        }
        // Invoke 'per bundle' alter hook.
        $this->moduleHandler
            ->alter('entity_bundle_field_info', $bundle_field_definitions, $entity_type, $bundle);
        return $bundle_field_definitions;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFieldStorageDefinitions($entity_type_id) {
        if (!isset($this->fieldStorageDefinitions[$entity_type_id])) {
            $this->fieldStorageDefinitions[$entity_type_id] = [];
            // Add all non-computed base fields.
            foreach ($this->getBaseFieldDefinitions($entity_type_id) as $field_name => $definition) {
                if (!$definition->isComputed()) {
                    $this->fieldStorageDefinitions[$entity_type_id][$field_name] = $definition;
                }
            }
            // Not prepared, try to load from cache.
            $cid = 'entity_field_storage_definitions:' . $entity_type_id . ':' . $this->languageManager
                ->getCurrentLanguage()
                ->getId();
            if ($cache = $this->cacheGet($cid)) {
                $field_storage_definitions = $cache->data;
            }
            else {
                // Rebuild the definitions and put it into the cache.
                $field_storage_definitions = $this->buildFieldStorageDefinitions($entity_type_id);
                $this->cacheSet($cid, $field_storage_definitions, Cache::PERMANENT, [
                    'entity_types',
                    'entity_field_info',
                ]);
            }
            $this->fieldStorageDefinitions[$entity_type_id] += $field_storage_definitions;
        }
        return $this->fieldStorageDefinitions[$entity_type_id];
    }
    
    /**
     * Gets the active field storage definitions for a content entity type.
     *
     * @param string $entity_type_id
     *   The entity type ID. Only content entities are supported.
     *
     * @return \Drupal\Core\Field\FieldStorageDefinitionInterface[]
     *   An array of field storage definitions that are active in the current
     *   request, keyed by field name.
     *
     * @internal
     */
    public function getActiveFieldStorageDefinitions($entity_type_id) {
        if (!isset($this->activeFieldStorageDefinitions[$entity_type_id])) {
            $this->activeFieldStorageDefinitions[$entity_type_id] = $this->entityLastInstalledSchemaRepository
                ->getLastInstalledFieldStorageDefinitions($entity_type_id);
        }
        return $this->activeFieldStorageDefinitions[$entity_type_id] ?: $this->getFieldStorageDefinitions($entity_type_id);
    }
    
    /**
     * {@inheritdoc}
     */
    public function setFieldMap(array $field_map) {
        $this->fieldMap = $field_map;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFieldMap() {
        if (!$this->fieldMap) {
            // Not prepared, try to load from cache.
            $cid = 'entity_field_map';
            if ($cache = $this->cacheGet($cid)) {
                $this->fieldMap = $cache->data;
            }
            else {
                // The field map is built in two steps. First, add all base fields, by
                // looping over all fieldable entity types. They always exist for all
                // bundles, and we do not expect to have so many different entity
                // types for this to become a bottleneck.
                foreach ($this->entityTypeManager
                    ->getDefinitions() as $entity_type_id => $entity_type) {
                    if ($entity_type->entityClassImplements(FieldableEntityInterface::class)) {
                        $bundles = array_keys($this->entityTypeBundleInfo
                            ->getBundleInfo($entity_type_id));
                        foreach ($this->getBaseFieldDefinitions($entity_type_id) as $field_name => $base_field_definition) {
                            $this->fieldMap[$entity_type_id][$field_name] = [
                                'type' => $base_field_definition->getType(),
                                'bundles' => array_combine($bundles, $bundles),
                            ];
                        }
                    }
                }
                // In the second step, the per-bundle fields are added, based on the
                // persistent bundle field map stored in a key value collection. This
                // data is managed in the
                // FieldDefinitionListener::onFieldDefinitionCreate() and
                // FieldDefinitionListener::onFieldDefinitionDelete() methods.
                // Rebuilding this information in the same way as base fields would not
                // scale, as the time to query would grow exponentially with more fields
                // and bundles. A cache would be deleted during cache clears, which is
                // the only time it is needed, so a key value collection is used.
                $bundle_field_maps = $this->keyValueFactory
                    ->get('entity.definitions.bundle_field_map')
                    ->getAll();
                foreach ($bundle_field_maps as $entity_type_id => $bundle_field_map) {
                    foreach ($bundle_field_map as $field_name => $map_entry) {
                        if (!isset($this->fieldMap[$entity_type_id][$field_name])) {
                            $this->fieldMap[$entity_type_id][$field_name] = $map_entry;
                        }
                        else {
                            $this->fieldMap[$entity_type_id][$field_name]['bundles'] += $map_entry['bundles'];
                        }
                    }
                }
                $this->cacheSet($cid, $this->fieldMap, Cache::PERMANENT, [
                    'entity_types',
                    'entity_field_info',
                ]);
            }
        }
        return $this->fieldMap;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFieldMapByFieldType($field_type) {
        if (!isset($this->fieldMapByFieldType[$field_type])) {
            $filtered_map = [];
            $map = $this->getFieldMap();
            foreach ($map as $entity_type => $fields) {
                foreach ($fields as $field_name => $field_info) {
                    if ($field_info['type'] == $field_type) {
                        $filtered_map[$entity_type][$field_name] = $field_info;
                    }
                }
            }
            $this->fieldMapByFieldType[$field_type] = $filtered_map;
        }
        return $this->fieldMapByFieldType[$field_type];
    }
    
    /**
     * Builds field storage definitions for an entity type.
     *
     * @param string $entity_type_id
     *   The entity type ID. Only entity types that implement
     *   \Drupal\Core\Entity\FieldableEntityInterface are supported
     *
     * @return \Drupal\Core\Field\FieldStorageDefinitionInterface[]
     *   An array of field storage definitions, keyed by field name.
     */
    protected function buildFieldStorageDefinitions($entity_type_id) {
        $entity_type = $this->entityTypeManager
            ->getDefinition($entity_type_id);
        $field_definitions = [];
        // Retrieve base field definitions from modules.
        $this->moduleHandler
            ->invokeAllWith('entity_field_storage_info', function (callable $hook, string $module) use (&$field_definitions, $entity_type, $entity_type_id) {
            $module_definitions = $hook($entity_type) ?? [];
            // Ensure the provider key actually matches the name of the provider
            // defining the field.
            foreach ($module_definitions as $field_name => $definition) {
                // @todo Remove this check once FieldDefinitionInterface exposes a
                //   proper provider setter. See https://www.drupal.org/node/2346329.
                if ($definition instanceof BaseFieldDefinition) {
                    $definition->setProvider($module);
                    $definition->setName($field_name);
                    $definition->setTargetEntityTypeId($entity_type_id);
                }
                $field_definitions[$field_name] = $definition;
            }
        });
        // Invoke alter hook.
        $this->moduleHandler
            ->alter('entity_field_storage_info', $field_definitions, $entity_type);
        return $field_definitions;
    }
    
    /**
     * {@inheritdoc}
     */
    public function clearCachedFieldDefinitions() {
        $this->baseFieldDefinitions = [];
        $this->fieldDefinitions = [];
        $this->fieldStorageDefinitions = [];
        $this->activeFieldStorageDefinitions = [];
        $this->fieldMap = [];
        $this->fieldMapByFieldType = [];
        $this->entityDisplayRepository
            ->clearDisplayModeInfo();
        $this->extraFields = NULL;
        Cache::invalidateTags([
            'entity_field_info',
        ]);
        // The typed data manager statically caches prototype objects with injected
        // definitions, clear those as well.
        $this->typedDataManager
            ->clearCachedDefinitions();
    }
    
    /**
     * {@inheritdoc}
     */
    public function useCaches($use_caches = FALSE) {
        $this->useCaches = $use_caches;
        if (!$use_caches) {
            $this->fieldDefinitions = [];
            $this->baseFieldDefinitions = [];
            $this->fieldStorageDefinitions = [];
            $this->activeFieldStorageDefinitions = [];
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getExtraFields($entity_type_id, $bundle) {
        $this->extraFields ??= $this->loadExtraFields();
        // Read from the "static" cache.
        // Return an empty fallback if the bundle has no extra fields.
        return $this->extraFields[$entity_type_id][$bundle] ?? [
            'form' => [],
            'display' => [],
        ];
    }
    
    /**
     * Loads extra fields from cache, or rebuilds them.
     *
     * @return array[][][][]
     *   Extra fields by entity type, bundle name, type (form/display) and
     *   extra field name.
     */
    protected function loadExtraFields() : array {
        // Read from the persistent cache. Since hook_entity_extra_field_info() and
        // hook_entity_extra_field_info_alter() might contain t() calls, we cache
        // per language.
        $cache_id = 'entity_extra_field_info:' . $this->languageManager
            ->getCurrentLanguage()
            ->getId();
        $cached = $this->cacheGet($cache_id);
        if ($cached) {
            return $cached->data;
        }
        $extra = $this->moduleHandler
            ->invokeAll('entity_extra_field_info');
        $this->moduleHandler
            ->alter('entity_extra_field_info', $extra);
        // Apply default values to each bundle.
        foreach ($extra as $entity_type_id => $extra_fields_by_bundle) {
            foreach ($extra_fields_by_bundle as $bundle => $bundle_extra_fields) {
                $extra[$entity_type_id][$bundle] += [
                    'form' => [],
                    'display' => [],
                ];
            }
        }
        $this->cacheSet($cache_id, $extra, Cache::PERMANENT, [
            'entity_field_info',
        ]);
        return $extra;
    }

}