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Re: Proposal: cpio-mode
From: |
Stefan Monnier |
Subject: |
Re: Proposal: cpio-mode |
Date: |
Thu, 16 Apr 2015 16:42:45 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) |
> A cpio mode has been in the emacs TODO file for as long as I've looked there.
> I'd like to write that. Is there really still interest?
It'd fit very nicely in GNU ELPA, I think, yes. Of course, the fact
that noone wrote one up might indicate that the demand is not very high,
but I for one would enjoy easier access to the initramfs files, for example.
Stefan
PS: For what it's worth, here's my earlier attempt at such a thing.
Obviously I stopped before getting to the meat of it.
PPS: Also, there are various possible options in terms of UI: you could
integrate cpio support into arc-mode.el, or you could "do it by hand"
along the lines of tar-mode.el, or you make a magic file-name handler
(and rely on dired for the UI).
;;; cpio-mode.el --- View/edit cpio archives
;; Copyright (C) 2012 Stefan Monnier
;; Author: Stefan Monnier <address@hidden>
;; Keywords:
;; This program 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.
;; This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;;; Code:
;; The format supported is the "New ASCII Format" as documented in
;; http://people.freebsd.org/~kientzle/libarchive/man/cpio.5.txt.
(eval-when-compile (require 'cl))
;;;###autoload
(add-to-list 'auto-mode-alist '("\\.cpio\\'" . cpio-mode))
;;;###autoload
(when (boundp 'inhibit-local-variables-regexps)
(add-to-list 'inhibit-local-variables-regexps "\\.cpio\\'"))
;;;###autoload
(define-derived-mode cpio-mode special-mode "CPIO"
"View/edit cpio archives."
(add-hook 'change-major-mode-hook
(lambda () (with-silent-modifications
(save-restriction
(widen)
(remove-text-properties (point-min) (point-max)
'(display nil invisible nil))))))
(cpio--parse-buffer))
(defun cpio--parse-mode (mode)
(string
(case (logand #o170000 mode)
(#o140000 ?s)
(#o120000 ?l)
(#o100000 ?-)
(#o060000 ?b)
(#o040000 ?d)
(#o020000 ?c)
(#o010000 ?p)
(t (error "Unknown mode %S" mode)))
(if (zerop (logand #o400 mode)) ?- ?r)
(if (zerop (logand #o200 mode)) ?- ?w)
(if (zerop (logand #o100 mode))
(if (zerop (logand #o4000 mode)) ?- ?S)
(if (zerop (logand #o4000 mode)) ?x ?s))
(if (zerop (logand #o040 mode)) ?- ?r)
(if (zerop (logand #o020 mode)) ?- ?w)
(if (zerop (logand #o010 mode))
(if (zerop (logand #o2000 mode)) ?- ?S)
(if (zerop (logand #o2000 mode)) ?x ?s))
(if (zerop (logand #o004 mode)) ?- ?r)
(if (zerop (logand #o002 mode)) ?- ?w)
(if (zerop (logand #o001 mode)) ?- ?x)))
(defun cpio--parse-buffer ()
(save-excursion
(save-restriction
(widen)
(goto-char (point-min))
(with-silent-modifications
(while (not (eobp))
(assert (zerop (mod (- (point) (point-min)) 4)))
(cond
((not (looking-at
"07070[12]\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)\\([[:xdigit:]]\\{8\\}\\)[[:xdigit:]]\\{8\\}\\|\0+\\'"))
(error "Unrecognized cpio header format"))
((not (match-beginning 1))
;; Reached the trailing padding, just skip it.
(put-text-property (point) (point-max) 'invisible t)
(goto-char (match-end 0)))
(t
(let* ((ino (string-to-number (match-string 1) 16))
(mode (string-to-number (match-string 2) 16))
(uid (string-to-number (match-string 3) 16))
(gid (string-to-number (match-string 4) 16))
(nlink (string-to-number (match-string 5) 16))
(mtime (string-to-number (match-string 6) 16))
(filesize (string-to-number (match-string 7) 16))
(devmajor (string-to-number (match-string 8) 16))
(devminor (string-to-number (match-string 9) 16))
(rdevmajor (string-to-number (match-string 10) 16))
(rdevminor (string-to-number (match-string 11) 16))
(namesize (string-to-number (match-string 12) 16))
(namebeg (match-end 0))
(name (buffer-substring namebeg (+ namebeg namesize -1)))
(filebeg (+ (match-end 0) 2 (* (/ (+ namesize 1) 4) 4)))
(next (+ filebeg (* (/ (+ filesize 3) 4) 4))))
(if (and (zerop ino) (zerop mode) (zerop filesize)
(equal name "TRAILER!!!"))
(put-text-property (match-beginning 0) next
'display "\n<trailer>")
(if (bobp)
(put-text-property (point) (match-end 1) 'invisible t)
(put-text-property (point) (match-end 1) 'display "\n"))
(put-text-property (match-beginning 2) (match-end 2)
'display (cpio--parse-mode mode))
(put-text-property (match-beginning 3) (match-end 3)
'display (format "%10d" uid))
(put-text-property (match-beginning 4) (match-end 4)
'display (format "/%-10d" gid))
(put-text-property (match-beginning 5) ;; (match-end 6)
;; 'invisible t)
;; (put-text-property (match-beginning 7)
(match-end 7)
'display (format "%10d" filesize))
(put-text-property (match-beginning 8) namebeg
'display " ")
(if (= (logand #o170000 mode) #o120000) ;Symlink
(progn
(put-text-property (+ namebeg namesize -1) filebeg
'display " -> ")
(put-text-property (+ filebeg filesize) next
'invisible t))
(put-text-property (+ namebeg namesize -1) next
'invisible t))
(message "Parsed %S of size %d" name filesize))
(goto-char next)))))))))
(provide 'cpio-mode)
;;; cpio-mode.el ends here