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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 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
;;; 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 GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix nar)
#:use-module (guix utils)
#:use-module (guix serialization)
#:use-module (rnrs bytevectors)
#:use-module (rnrs io ports)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (ice-9 ftw)
#:export (write-file))
;;; Comment:
;;;
;;; Read and write Nix archives, aka. ‘nar’.
;;;
;;; Code:
(define (write-contents file p size)
"Write SIZE bytes from FILE to output port P."
(define (call-with-binary-input-file file proc)
;; Open FILE as a binary file. This avoids scan-for-encoding, and thus
;; avoids any initial buffering. Disable file name canonicalization to
;; avoid stat'ing like crazy.
(with-fluids ((%file-port-name-canonicalization #f))
(let ((port (open-file file "rb")))
(catch #t (cut proc port)
(lambda args
(close-port port)
(apply throw args))))))
(define (dump in size)
(define buf-size 65536)
(define buf (make-bytevector buf-size))
(let loop ((left size))
(if (<= left 0)
0
(let ((read (get-bytevector-n! in buf 0 buf-size)))
(if (eof-object? read)
left
(begin
(put-bytevector p buf 0 read)
(loop (- left read))))))))
(write-string "contents" p)
(write-long-long size p)
(call-with-binary-input-file file
;; Use `sendfile' when available (Guile 2.0.8+).
(if (compile-time-value (defined? 'sendfile))
(cut sendfile p <> size 0)
(cut dump <> size)))
(write-padding size p))
(define (write-file file port)
"Write the contents of FILE to PORT in Nar format, recursing into
sub-directories of FILE as needed."
(define %archive-version-1 "nix-archive-1")
(define p port)
(write-string %archive-version-1 p)
(let dump ((f file))
(let ((s (lstat f)))
(write-string "(" p)
(case (stat:type s)
((regular)
(write-string "type" p)
(write-string "regular" p)
(if (not (zero? (logand (stat:mode s) #o100)))
(begin
(write-string "executable" p)
(write-string "" p)))
(write-contents f p (stat:size s)))
((directory)
(write-string "type" p)
(write-string "directory" p)
(let ((entries (remove (cut member <> '("." ".."))
(scandir f))))
(for-each (lambda (e)
(let ((f (string-append f "/" e)))
(write-string "entry" p)
(write-string "(" p)
(write-string "name" p)
(write-string e p)
(write-string "node" p)
(dump f)
(write-string ")" p)))
entries)))
(else
(error "ENOSYS")))
(write-string ")" p))))
;;; nar.scm ends here
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