interface ConfigStorageInterface

interface ConfigStorageInterface {

  /**
   * Perform any steps needed to create and initialize the storage.  This may
   * include creating directories or database tables, and initializing data
   * structures.
   *
   * This function does not re-initialize already initialized storage.
   *
   * @return bool
   *   TRUE on success, FALSE in case of an error.
   *
   * @throws ConfigStorageException
   */
  public function initializeStorage();

  /**
   * Return the storage protocol for the settings string.  E.g., for file-based
   * config that parses file://path/to/config, this function returns 'file'.
   *
   * @return string
   *   The protocol part of the storage URL this class supports.
   */
  public static function urlPrefix();

  /**
   * Check that the storage managed by this object is present and functional.
   *
   * @return bool
   *   TRUE on success, FALSE in case of an error.
   */
  public function isInitialized();

  /**
   * Returns whether data in this object can be changed.
   *
   * @return bool
   *   TRUE if the object cannot be changed, FALSE if it can be changed.
   */
  public function isImmutable();

  /**
   * Returns whether a configuration object exists.
   *
   * @param string $name
   *   The name of a configuration object to test.
   *
   * @return bool
   *   TRUE if the configuration object exists, FALSE otherwise.
   */
  public function exists($name);

  /**
   * Reads configuration data from the storage.
   *
   * @param string $name
   *   The name of a configuration object to load.
   *
   * @throws ConfigStorageReadException
   *
   * @return array|bool
   *   The configuration data stored for the configuration object name. If no
   *   configuration data exists for the given name, FALSE is returned.
   */
  public function read($name);

  /**
   * Reads configuration data from the storage.
   *
   * @param array $name
   *   List of names of the configuration objects to load.
   *
   * @throws ConfigStorageException
   *
   * @return array
   *   A list of the configuration data stored for the configuration object name
   *   that could be loaded for the passed list of names.
   */
  public function readMultiple(array $names);

  /**
   * Writes configuration data to the storage.
   *
   * @param string $name
   *   The name of a configuration object to save.
   * @param array $data
   *   The configuration data to write.
   *
   * @return bool
   *   TRUE on success, FALSE in case of an error.
   */
  public function write($name, array $data);

  /**
   * Deletes a configuration object from the storage.
   *
   * @param string $name
   *   The name of a configuration object to delete.
   *
   * @return bool
   *   TRUE on success, FALSE otherwise.
   */
  public function delete($name);

  /**
   * Renames a configuration object in the storage.
   *
   * @param string $name
   *   The name of a configuration object to rename.
   * @param string $new_name
   *   The new name of a configuration object.
   *
   * @return bool
   *   TRUE on success, FALSE otherwise.
   */
  public function rename($name, $new_name);


  /**
   * Returns a timestamp indicating the last time a configuration was modified.
   *
   * @param string $name
   *   The name of a configuration object on which the time will be checked.
   *
   * @return int|FALSE
   *   A timestamp indicating the last time the configuration was modified or
   *   FALSE if the named configuration object doesn't exist.
   */
  public function getModifiedTime($name);

  /**
   * Encodes configuration data into the storage-specific format.
   *
   * @param array $data
   *   The configuration data to encode.
   *
   * @return string
   *   The encoded configuration data.
   *
   * This is a publicly accessible static method to allow for alternative
   * usages in data conversion scripts and also tests.
   */
  public function encode($data);

  /**
   * Decodes configuration data from the storage-specific format.
   *
   * @param string $raw
   *   The raw configuration data string to decode.
   *
   * @return array
   *   The decoded configuration data as an associative array.
   *
   * This is a publicly accessible static method to allow for alternative
   * usages in data conversion scripts and also tests.
   */
  public function decode($raw);

  /**
   * Gets configuration object names starting with a given prefix.
   *
   * Given the following configuration objects:
   * - node.type.post
   * - node.type.page
   *
   * Passing the prefix 'node.type.' will return an array containing the above
   * names.
   *
   * @param string $prefix
   *   (optional) The prefix to search for. If omitted, all configuration object
   *   names that exist are returned.
   *
   * @return array
   *   An array containing matching configuration object names.
   */
  public function listAll($prefix = '');

  /**
   * Deletes configuration objects whose names start with a given prefix.
   *
   * Given the following configuration object names:
   * - node.type.post
   * - node.type.page
   *
   * Passing the prefix 'node.type.' will delete the above configuration
   * objects.
   *
   * @param string $prefix
   *   (optional) The prefix to search for. If omitted, all configuration
   *   objects that exist will be deleted.
   *
   * @return boolean
   *   TRUE on success, FALSE otherwise.
   */
  public function deleteAll($prefix = '');

  /**
   * Import an archive of configuration files into the config storage managed
   * by this object.
   *
   * @param string $file_uri
   *   The URI of the tar archive file to import.
   *
   * @throws ConfigStorageException
   *
   * @return bool
   *   TRUE on success, FALSE otherwise.
   */
  public function importArchive($file_uri);

  /**
   * Export an archive of configuration files from the config storage managed
   * by this object.
   *
   * @param string $file_uri
   *   The URI of the tar archive file to create.
   *
   * @throws ConfigStorageException
   *
   * @return bool
   *   TRUE on success, FALSE otherwise.
   */
  public function exportArchive($file_uri);
}