Mirror of GNU Guix
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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013, 2014 Ludovic Courtès <ludo@gnu.org>
;;; This file is part of GNU Guix.
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; GNU General Public License for more details.
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix serialization)
#:use-module (guix utils)
#:use-module (rnrs bytevectors)
#:use-module (rnrs io ports)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (ice-9 match)
#:export (write-int read-int
write-long-long read-long-long
write-string read-string read-latin1-string
write-string-list read-string-list
write-store-path read-store-path
write-store-path-list read-store-path-list))
;;; Comment:
;;; Serialization procedures used by the RPCs and the Nar format. This module
;;; is for internal consumption.
;;; Code:
;; Similar to serialize.cc in Nix.
(define (write-int n p)
(let ((b (make-bytevector 8 0)))
(bytevector-u32-set! b 0 n (endianness little))
(put-bytevector p b)))
(define (read-int p)
(let ((b (get-bytevector-n p 8)))
(bytevector-u32-ref b 0 (endianness little))))
(define (write-long-long n p)
(let ((b (make-bytevector 8 0)))
(bytevector-u64-set! b 0 n (endianness little))
(put-bytevector p b)))
(define (read-long-long p)
(let ((b (get-bytevector-n p 8)))
(bytevector-u64-ref b 0 (endianness little))))
(define write-padding
(let ((zero (make-bytevector 8 0)))
(lambda (n p)
(let ((m (modulo n 8)))
(or (zero? m)
(put-bytevector p zero 0 (- 8 m)))))))
(define (write-string s p)
(let* ((s (string->utf8 s))
(l (bytevector-length s))
(m (modulo l 8))
(b (make-bytevector (+ 8 l (if (zero? m) 0 (- 8 m))))))
(bytevector-u32-set! b 0 l (endianness little))
(bytevector-copy! s 0 b 8 l)
(put-bytevector p b)))
(define (read-string p)
(let* ((len (read-int p))
(m (modulo len 8))
(bv (get-bytevector-n p len))
(str (utf8->string bv)))
(or (zero? m)
(get-bytevector-n p (- 8 m)))
(define (read-latin1-string p)
(let* ((len (read-int p))
(m (modulo len 8))
(str (get-string-n p len)))
(or (zero? m)
(get-bytevector-n p (- 8 m)))
(define (write-string-list l p)
(write-int (length l) p)
(for-each (cut write-string <> p) l))
(define (write-string-pairs l p)
(write-int (length l) p)
(for-each (match-lambda
((first . second)
(write-string first p)
(write-string second p)))
(define (read-string-list p)
(let ((len (read-int p)))
(unfold (cut >= <> len)
(lambda (i)
(read-string p))
(define (write-store-path f p)
(write-string f p)) ; TODO: assert path
(define (read-store-path p)
(read-string p)) ; TODO: assert path
(define write-store-path-list write-string-list)
(define read-store-path-list read-string-list)
;;; serialization.scm ends here