interface StorageComparerInterface

interface StorageComparerInterface {
    
    /**
     * Gets the configuration source storage.
     *
     * @param string $collection
     *   (optional) The storage collection to use. Defaults to the
     *   default collection.
     *
     * @return \Drupal\Core\Config\StorageInterface
     *   Storage object used to read configuration.
     */
    public function getSourceStorage($collection = StorageInterface::DEFAULT_COLLECTION);
    
    /**
     * Gets the configuration target storage.
     *
     * @param string $collection
     *   (optional) The storage collection to use. Defaults to the
     *   default collection.
     *
     * @return \Drupal\Core\Config\StorageInterface
     *   Storage object used to write configuration.
     */
    public function getTargetStorage($collection = StorageInterface::DEFAULT_COLLECTION);
    
    /**
     * Gets an empty changelist.
     *
     * @return array
     *   An empty changelist array.
     */
    public function getEmptyChangelist();
    
    /**
     * Gets the list of differences to import.
     *
     * @param string $op
     *   (optional) A change operation. Either delete, create or update. If
     *   supplied the returned list will be limited to this operation.
     * @param string $collection
     *   (optional) The collection to get the changelist for. Defaults to the
     *   default collection.
     *
     * @return array
     *   An array of config changes that are yet to be imported.
     */
    public function getChangelist($op = NULL, $collection = StorageInterface::DEFAULT_COLLECTION);
    
    /**
     * Recalculates the differences.
     *
     * @return $this
     *   An object which implements the StorageComparerInterface.
     */
    public function reset();
    
    /**
     * Checks if there are any operations with changes to process.
     *
     * Until the changelist has been calculated this will always be FALSE.
     *
     * @return bool
     *   TRUE if there are changes to process and FALSE if not.
     *
     * @see \Drupal\Core\Config\StorageComparerInterface::createChangelist()
     */
    public function hasChanges();
    
    /**
     * Validates that the system.site::uuid in the source and target match.
     *
     * @return bool
     *   TRUE if identical, FALSE if not.
     */
    public function validateSiteUuid();
    
    /**
     * Moves a rename operation to an update.
     *
     * @param string $rename
     *   The rename name, as provided by ConfigImporter::createRenameName().
     * @param string $collection
     *   (optional) The collection where the configuration is stored. Defaults to
     *   the default collection.
     *
     * @see \Drupal\Core\Config\ConfigImporter::createRenameName()
     */
    public function moveRenameToUpdate($rename, $collection = StorageInterface::DEFAULT_COLLECTION);
    
    /**
     * Extracts old and new configuration names from a configuration change name.
     *
     * @param string $name
     *   The configuration change name, as provided by
     *   ConfigImporter::createRenameName().
     *
     * @return array
     *   An associative array of configuration names. The array keys are
     *   'old_name' and 'new_name' representing the old and new configuration
     *   object names during a rename operation.
     *
     * @see \Drupal\Core\Config\StorageComparer::createRenameNames()
     */
    public function extractRenameNames($name);
    
    /**
     * Gets the existing collections from both the target and source storage.
     *
     * @param bool $include_default
     *   (optional) Include the default collection. Defaults to TRUE.
     *
     * @return array
     *   An array of existing collection names.
     */
    public function getAllCollectionNames($include_default = TRUE);

}