;; This file is part of eris-cl.
;; Copyright (C) 2022 Piotr Szarmański

;; eris-cl is free software: you can redistribute it and/or modify it under the
;; terms of the GNU Lesser General Public License as published by the Free
;; Software Foundation, either version 3 of the License, or (at your option) any
;; later version.

;; eris-cl is distributed in the hope that it will be useful, but WITHOUT ANY
;; WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
;; A PARTICULAR PURPOSE. See the GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License along with
;; eris-cl. If not, see <https://www.gnu.org/licenses/>.

;; This file contains the backend protocol.
(in-package :eris)

(defclass encoding-backend ()
  ((output-function :type function)))

(defclass decoding-backend ()
  ((fetch-function :type function)))

(defgeneric fetch-data (read-capability backend &key &allow-other-keys)
  (:documentation
   "Using the BACKEND, return a stream that decodes the provided READ-CAPABILITY
object."))

(defgeneric store-data (input backend &key secret &allow-other-keys)
  (:documentation
   "Using the BACKEND, store the INPUT, which is either a stream or an octet
vector. An additional 32-byte octet-vector SECRET can be provided in order to
protect the data from attacks against convergent encryption."))