interface EntityDefinitionUpdateManagerInterface

interface EntityDefinitionUpdateManagerInterface {
    
    /**
     * Indicates that a definition has just been created.
     *
     * @var int
     */
    const DEFINITION_CREATED = 1;
    
    /**
     * Indicates that a definition has changes.
     *
     * @var int
     */
    const DEFINITION_UPDATED = 2;
    
    /**
     * Indicates that a definition has just been deleted.
     *
     * @var int
     */
    const DEFINITION_DELETED = 3;
    
    /**
     * Checks if there are any definition updates that need to be applied.
     *
     * @return bool
     *   TRUE if updates are needed.
     */
    public function needsUpdates();
    
    /**
     * Gets a human readable summary of the detected changes.
     *
     * @return array
     *   An associative array keyed by entity type id. Each entry is an array of
     *   human-readable strings, each describing a change.
     */
    public function getChangeSummary();
    
    /**
     * Gets a list of changes to entity type and field storage definitions.
     *
     * @return array
     *   An associative array keyed by entity type ID of change descriptors. Every
     *   entry is an associative array with the following optional keys:
     *   - entity_type: a scalar having one value among:
     *     - EntityDefinitionUpdateManagerInterface::DEFINITION_CREATED
     *     - EntityDefinitionUpdateManagerInterface::DEFINITION_UPDATED
     *   - field_storage_definitions: an associative array keyed by field name of
     *     scalars having one value among:
     *     - EntityDefinitionUpdateManagerInterface::DEFINITION_CREATED
     *     - EntityDefinitionUpdateManagerInterface::DEFINITION_UPDATED
     *     - EntityDefinitionUpdateManagerInterface::DEFINITION_DELETED
     */
    public function getChangeList();
    
    /**
     * Returns an entity type definition ready to be manipulated.
     *
     * When needing to apply updates to existing entity type definitions, this
     * method should always be used to retrieve a definition ready to be
     * manipulated.
     *
     * @param string $entity_type_id
     *   The entity type identifier.
     *
     * @return \Drupal\Core\Entity\EntityTypeInterface|null
     *   The entity type definition. Or NULL if not found.
     */
    public function getEntityType($entity_type_id);
    
    /**
     * Returns all the entity type definitions, ready to be manipulated.
     *
     * When needing to apply updates to existing entity type definitions, this
     * method should always be used to retrieve all the definitions ready to be
     * manipulated.
     *
     * @return \Drupal\Core\Entity\EntityTypeInterface[]
     *   The last installed entity type definitions, keyed by the entity type ID.
     */
    public function getEntityTypes();
    
    /**
     * Installs a new entity type definition.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition.
     */
    public function installEntityType(EntityTypeInterface $entity_type);
    
    /**
     * Installs a new fieldable entity type definition.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition.
     * @param \Drupal\Core\Field\FieldStorageDefinitionInterface[] $field_storage_definitions
     *   The entity type's field storage definitions.
     */
    public function installFieldableEntityType(EntityTypeInterface $entity_type, array $field_storage_definitions);
    
    /**
     * Applies any change performed to the passed entity type definition.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition.
     */
    public function updateEntityType(EntityTypeInterface $entity_type);
    
    /**
     * Uninstalls an entity type definition.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The entity type definition.
     */
    public function uninstallEntityType(EntityTypeInterface $entity_type);
    
    /**
     * Applies any change performed to a fieldable entity type definition.
     *
     * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
     *   The updated entity type definition.
     * @param \Drupal\Core\Field\FieldStorageDefinitionInterface[] $field_storage_definitions
     *   The updated field storage definitions, including possibly new ones.
     * @param array &$sandbox
     *   (optional) A sandbox array provided by a hook_update_N() implementation
     *   or a Batch API callback. If the entity schema update requires a data
     *   migration, this parameter is mandatory. Defaults to NULL.
     */
    public function updateFieldableEntityType(EntityTypeInterface $entity_type, array $field_storage_definitions, array &$sandbox = NULL);
    
    /**
     * Returns a field storage definition ready to be manipulated.
     *
     * When needing to apply updates to existing field storage definitions, this
     * method should always be used to retrieve a storage definition ready to be
     * manipulated.
     *
     * @param string $name
     *   The field name.
     * @param string $entity_type_id
     *   The entity type identifier.
     *
     * @return \Drupal\Core\Field\FieldStorageDefinitionInterface|null
     *   The field storage definition or NULL if there is none for the given field
     *   name and entity type.
     *
     * @todo Make this return a mutable storage definition interface when we have
     *   one. See https://www.drupal.org/node/2346329.
     */
    public function getFieldStorageDefinition($name, $entity_type_id);
    
    /**
     * Installs a new field storage definition.
     *
     * @param string $name
     *   The field storage definition name.
     * @param string $entity_type_id
     *   The target entity type identifier.
     * @param string $provider
     *   The name of the definition provider.
     * @param \Drupal\Core\Field\FieldStorageDefinitionInterface $storage_definition
     *   The field storage definition.
     */
    public function installFieldStorageDefinition($name, $entity_type_id, $provider, FieldStorageDefinitionInterface $storage_definition);
    
    /**
     * Applies any change performed to the passed field storage definition.
     *
     * @param \Drupal\Core\Field\FieldStorageDefinitionInterface $storage_definition
     *   The field storage definition.
     */
    public function updateFieldStorageDefinition(FieldStorageDefinitionInterface $storage_definition);
    
    /**
     * Uninstalls a field storage definition.
     *
     * @param \Drupal\Core\Field\FieldStorageDefinitionInterface $storage_definition
     *   The field storage definition.
     */
    public function uninstallFieldStorageDefinition(FieldStorageDefinitionInterface $storage_definition);

}