Version 1

[yaffs-website] / web / core / lib / Drupal / Core / Entity / Schema / EntityStorageSchemaInterface.php

diff --git a/web/core/lib/Drupal/Core/Entity/Schema/EntityStorageSchemaInterface.php b/web/core/lib/Drupal/Core/Entity/Schema/EntityStorageSchemaInterface.php
new file mode 100644 (file)
index 0000000..4feab7b
--- /dev/null
+++ b/web/core/lib/Drupal/Core/Entity/Schema/EntityStorageSchemaInterface.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace Drupal\Core\Entity\Schema;
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Entity\EntityTypeListenerInterface;
+
+/**
+ * Defines the interface for entity storage schema handler classes.
+ *
+ * An entity type's storage schema handler is responsible for creating the
+ * storage backend's schema that the entity type's storage handler needs for
+ * storing its entities. For example, if the storage handler is for a SQL
+ * backend, then the storage schema handler is responsible for creating the
+ * needed tables. During the application lifetime, an entity type's definition
+ * can change in a way that requires changes to the storage schema, so this
+ * interface defines methods for that as well.
+ *
+ * @see \Drupal\Core\Entity\EntityStorageInterface
+ */
+interface EntityStorageSchemaInterface extends EntityTypeListenerInterface {
+
+  /**
+   * Checks if the changes to the entity type requires storage schema changes.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   *   The updated entity type definition.
+   * @param \Drupal\Core\Entity\EntityTypeInterface $original
+   *   The original entity type definition.
+   *
+   * @return bool
+   *   TRUE if storage schema changes are required, FALSE otherwise.
+   */
+  public function requiresEntityStorageSchemaChanges(EntityTypeInterface $entity_type, EntityTypeInterface $original);
+
+  /**
+   * Checks if existing data would be lost if the schema changes were applied.
+   *
+   * If there are no schema changes needed, then no data needs to be migrated,
+   * but it is not the responsibility of this function to recheck what
+   * requiresEntityStorageSchemaChanges() checks. Rather, the meaning of what
+   * this function returns when requiresEntityStorageSchemaChanges() returns
+   * FALSE is undefined. Callers are expected to only call this function when
+   * requiresEntityStorageSchemaChanges() is TRUE.
+   *
+   * This function can return FALSE if any of these conditions apply:
+   * - There are no existing entities for the entity type.
+   * - There are existing entities, but the schema changes can be applied
+   *   without losing their data (e.g., if the schema changes can be performed
+   *   by altering tables rather than dropping and recreating them).
+   * - The only entity data that would be lost are ones that are not valid for
+   *   the new definition (e.g., if changing an entity type from revisionable
+   *   to non-revisionable, then it's okay to drop data for the non-default
+   *   revision).
+   *
+   * When this function returns FALSE, site administrators will be unable to
+   * perform an automated update, and will instead need to perform a site
+   * migration or invoke some custom update process.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   *   The updated entity type definition.
+   * @param \Drupal\Core\Entity\EntityTypeInterface $original
+   *   The original entity type definition.
+   *
+   * @return bool
+   *   TRUE if data migration is required, FALSE otherwise.
+   *
+   * @see self::requiresEntityStorageSchemaChanges()
+   */
+  public function requiresEntityDataMigration(EntityTypeInterface $entity_type, EntityTypeInterface $original);
+
+}