diff options
| -rw-r--r-- | src/backend.lisp | 35 | ||||
| -rw-r--r-- | src/file-backend.lisp | 71 |
2 files changed, 106 insertions, 0 deletions
diff --git a/src/backend.lisp b/src/backend.lisp new file mode 100644 index 0000000..9bb00d0 --- /dev/null +++ b/src/backend.lisp @@ -0,0 +1,35 @@ +;; 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-read-capability (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.")) + diff --git a/src/file-backend.lisp b/src/file-backend.lisp new file mode 100644 index 0000000..2bb8693 --- /dev/null +++ b/src/file-backend.lisp @@ -0,0 +1,71 @@ +;; 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/>. + +(in-package :eris) + +(defclass file-backend (encoding-backend decoding-backend) + ((directory :initarg :directory :type (or string pathname) + :documentation + "Directory containing ERIS data."))) + + +(define-condition file-backend-error (error) + ()) + +(define-condition directory-error (file-backend-error) + ((message :type string :initarg :message)) + (:report (lambda (condition stream) + (format stream "~a" (slot-value condition 'message))))) + +(defmethod shared-initialize :after ((file-backend file-backend) slot-names + &rest initargs + &key (directory nil directory-p) + &allow-other-keys) + + (declare (ignore initargs slot-names)) + (when (or (null directory-p) (null (pathname-directory directory))) + (error 'directory-error :message "Incorrectly specified directory.")) + (with-slots (directory output-function fetch-function) file-backend + (when (or (pathname-name directory))) + (setf fetch-function + (lambda (reference) + (let* ((base32 (bytes-to-base32-unpadded reference)) + (file (merge-pathnames directory base32))) + (alexandria:read-file-into-byte-vector file))) + output-function + (lambda (block reference) + (let* ((base32 (bytes-to-base32-unpadded reference)) + (file (merge-pathnames directory base32))) + (unless (probe-file file) + (alexandria:write-byte-vector-into-file block file))))))) + +(defmethod fetch-read-capability (read-capability (backend file-backend) &key &allow-other-keys) + (declare (type read-capability read-capability)) + (with-slots (fetch-function) backend + (eris-decode read-capability fetch-function))) + +(defmethod store-data (input (backend file-backend) &key (secret null-secret) &allow-other-keys) + (declare (type octet-vector secret)) + (with-slots (output-function) backend + (eris-encode input + (if (> (etypecase input + (stream (file-length input)) + (vector (length input))) + 16384) + 32kib + 1kib) + output-function + :hash-output nil + :secret secret))) |