5 * Provides support for field data purge after mass deletion.
8 use Drupal\Core\Field\FieldDefinitionInterface;
9 use Drupal\Core\Field\FieldException;
10 use Drupal\Core\Field\FieldStorageDefinitionInterface;
13 * @defgroup field_purge Field API bulk data deletion
15 * Cleans up after Field API bulk deletion operations.
17 * Field API provides functions for deleting data attached to individual
18 * entities as well as deleting entire fields or field storages in a single
21 * When a single entity is deleted, the Entity storage performs the
22 * following operations:
23 * - Invoking the method \Drupal\Core\Field\FieldItemListInterface::delete() for
24 * each field on the entity. A file field type might use this method to delete
25 * uploaded files from the filesystem.
26 * - Removing the data from storage.
27 * - Invoking the global hook_entity_delete() for all modules that implement it.
28 * Each hook implementation receives the entity being deleted and can operate
29 * on whichever subset of the entity's bundle's fields it chooses to.
31 * Similar operations are performed on deletion of a single entity revision.
33 * When a bundle, field or field storage is deleted, it is not practical to
34 * perform those operations immediately on every affected entity in a single
35 * page request; there could be thousands or millions of them. Instead, the
36 * appropriate field data items, fields, and/or field storages are marked as
37 * deleted so that subsequent load or query operations will not return them.
38 * Later, a separate process cleans up, or "purges", the marked-as-deleted data
39 * by going through the three-step process described above and, finally,
40 * removing deleted field storage and field records.
42 * Purging field data is made somewhat tricky by the fact that, while
43 * $entity->delete() has a complete entity to pass to the various deletion
44 * steps, the Field API purge process only has the field data it has previously
45 * stored. It cannot reconstruct complete original entities to pass to the
46 * deletion operations. It is even possible that the original entity to which
47 * some Field API data was attached has been itself deleted before the field
48 * purge operation takes place.
50 * Field API resolves this problem by using stub entities during purge
51 * operations, containing only the information from the original entity that
52 * Field API knows about: entity type, ID, revision ID, and bundle. It also
53 * contains the field data for whichever field is currently being purged.
55 * See @link field Field API @endlink for information about the other parts of
60 * Purges a batch of deleted Field API data, field storages, or fields.
62 * This function will purge deleted field data in batches. The batch size
63 * is defined as an argument to the function, and once each batch is finished,
64 * it continues with the next batch until all have completed. If a deleted field
65 * with no remaining data records is found, the field itself will
66 * be purged. If a deleted field storage with no remaining fields is found, the
67 * field storage itself will be purged.
69 * @param int $batch_size
70 * The maximum number of field data records to purge before returning.
71 * @param string $field_storage_unique_id
72 * (optional) Limit the purge to a specific field storage. Defaults to NULL.
74 function field_purge_batch($batch_size, $field_storage_unique_id = NULL) {
75 /** @var \Drupal\Core\Field\DeletedFieldsRepositoryInterface $deleted_fields_repository */
76 $deleted_fields_repository = \Drupal::service('entity_field.deleted_fields_repository');
78 $fields = $deleted_fields_repository->getFieldDefinitions($field_storage_unique_id);
80 $info = \Drupal::entityManager()->getDefinitions();
81 foreach ($fields as $field) {
82 $entity_type = $field->getTargetEntityTypeId();
84 // We cannot purge anything if the entity type is unknown (e.g. the
85 // providing module was uninstalled).
86 // @todo Revisit after https://www.drupal.org/node/2080823.
87 if (!isset($info[$entity_type])) {
88 \Drupal::logger('field')->warning("Cannot remove field @field_name because the entity type is unknown: %entity_type", ['@field_name' => $field->getName(), '%entity_type' => $entity_type]);
92 $count_purged = \Drupal::entityManager()->getStorage($entity_type)->purgeFieldData($field, $batch_size);
93 if ($count_purged < $batch_size || $count_purged == 0) {
94 // No field data remains for the field, so we can remove it.
95 field_purge_field($field);
97 $batch_size -= $count_purged;
98 // Only delete up to the maximum number of records.
99 if ($batch_size == 0) {
104 // Retrieve all deleted field storages. Any that have no fields can be purged.
105 foreach ($deleted_fields_repository->getFieldStorageDefinitions() as $field_storage) {
106 if ($field_storage_unique_id && $field_storage->getUniqueStorageIdentifier() != $field_storage_unique_id) {
107 // If a specific UUID is provided, only purge the corresponding field.
111 // We cannot purge anything if the entity type is unknown (e.g. the
112 // providing module was uninstalled).
113 // @todo Revisit after https://www.drupal.org/node/2080823.
114 if (!isset($info[$field_storage->getTargetEntityTypeId()])) {
118 $fields = $deleted_fields_repository->getFieldDefinitions($field_storage->getUniqueStorageIdentifier());
119 if (empty($fields)) {
120 field_purge_field_storage($field_storage);
126 * Purges a field record from the database.
128 * This function assumes all data for the field has already been purged and
129 * should only be called by field_purge_batch().
131 * @param \Drupal\Core\Field\FieldDefinitionInterface $field
132 * The field to purge.
134 function field_purge_field(FieldDefinitionInterface $field) {
135 /** @var \Drupal\Core\Field\DeletedFieldsRepositoryInterface $deleted_fields_repository */
136 $deleted_fields_repository = \Drupal::service('entity_field.deleted_fields_repository');
137 $deleted_fields_repository->removeFieldDefinition($field);
139 // Invoke external hooks after the cache is cleared for API consistency.
140 \Drupal::moduleHandler()->invokeAll('field_purge_field', [$field]);
144 * Purges a field record from the database.
146 * This function assumes all fields for the field storage has already been
147 * purged, and should only be called by field_purge_batch().
149 * @param \Drupal\Core\Field\FieldStorageDefinitionInterface $field_storage
150 * The field storage to purge.
152 * @throws \Drupal\Core\Field\FieldException
154 function field_purge_field_storage(FieldStorageDefinitionInterface $field_storage) {
155 /** @var \Drupal\Core\Field\DeletedFieldsRepositoryInterface $deleted_fields_repository */
156 $deleted_fields_repository = \Drupal::service('entity_field.deleted_fields_repository');
158 $fields = $deleted_fields_repository->getFieldDefinitions($field_storage->getUniqueStorageIdentifier());
159 if (count($fields) > 0) {
160 throw new FieldException(t('Attempt to purge a field storage @field_name that still has fields.', ['@field_name' => $field_storage->getName()]));
163 $deleted_fields_repository->removeFieldStorageDefinition($field_storage);
165 // Notify the storage layer.
166 \Drupal::entityManager()->getStorage($field_storage->getTargetEntityTypeId())->finalizePurge($field_storage);
168 // Invoke external hooks after the cache is cleared for API consistency.
169 \Drupal::moduleHandler()->invokeAll('field_purge_field_storage', [$field_storage]);
173 * @} End of "defgroup field_purge".