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266 lines
8.7 KiB
EmacsLisp
266 lines
8.7 KiB
EmacsLisp
;;; epa-file.el --- the EasyPG Assistant, transparent file encryption
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;; Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
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;; Author: Daiki Ueno <ueno@unixuser.org>
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;; Keywords: PGP, GnuPG
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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;;; Code:
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(require 'epa)
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(require 'epa-hook)
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(defcustom epa-file-cache-passphrase-for-symmetric-encryption nil
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"If non-nil, cache passphrase for symmetric encryption."
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:type 'boolean
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:group 'epa-file)
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(defcustom epa-file-select-keys nil
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"If non-nil, always asks user to select recipients."
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:type 'boolean
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:group 'epa-file)
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(defvar epa-file-passphrase-alist nil)
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(eval-and-compile
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(if (fboundp 'encode-coding-string)
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(defalias 'epa-file--encode-coding-string 'encode-coding-string)
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(defalias 'epa-file--encode-coding-string 'identity)))
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(eval-and-compile
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(if (fboundp 'decode-coding-string)
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(defalias 'epa-file--decode-coding-string 'decode-coding-string)
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(defalias 'epa-file--decode-coding-string 'identity)))
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(defun epa-file-passphrase-callback-function (context key-id file)
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(if (and epa-file-cache-passphrase-for-symmetric-encryption
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(eq key-id 'SYM))
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(progn
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(setq file (file-truename file))
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(let ((entry (assoc file epa-file-passphrase-alist))
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passphrase)
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(or (copy-sequence (cdr entry))
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(progn
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(unless entry
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(setq entry (list file)
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epa-file-passphrase-alist
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(cons entry
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epa-file-passphrase-alist)))
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(setq passphrase (epa-passphrase-callback-function context
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key-id nil))
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(setcdr entry (copy-sequence passphrase))
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passphrase))))
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(epa-passphrase-callback-function context key-id nil)))
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;;;###autoload
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(defun epa-file-handler (operation &rest args)
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(save-match-data
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(let ((op (get operation 'epa-file)))
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(if op
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(apply op args)
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(epa-file-run-real-handler operation args)))))
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(defun epa-file-run-real-handler (operation args)
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(let ((inhibit-file-name-handlers
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(cons 'epa-file-handler
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(and (eq inhibit-file-name-operation operation)
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inhibit-file-name-handlers)))
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(inhibit-file-name-operation operation))
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(apply operation args)))
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(defun epa-file-decode-and-insert (string file visit beg end replace)
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(if (fboundp 'decode-coding-inserted-region)
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(save-restriction
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(narrow-to-region (point) (point))
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(let ((multibyte enable-multibyte-characters))
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(set-buffer-multibyte nil)
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(insert string)
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(set-buffer-multibyte multibyte)
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(decode-coding-inserted-region
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(point-min) (point-max)
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(substring file 0 (string-match epa-file-name-regexp file))
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visit beg end replace)))
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(insert (epa-file--decode-coding-string string (or coding-system-for-read
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'undecided)))))
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(defvar last-coding-system-used)
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(defun epa-file-insert-file-contents (file &optional visit beg end replace)
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(barf-if-buffer-read-only)
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(if (and visit (or beg end))
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(error "Attempt to visit less than an entire file"))
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(setq file (expand-file-name file))
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(let* ((local-copy
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(condition-case nil
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(epa-file-run-real-handler #'file-local-copy (list file))
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(error)))
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(local-file (or local-copy file))
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(context (epg-make-context))
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string length entry)
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(if visit
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(setq buffer-file-name file))
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(epg-context-set-passphrase-callback
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context
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(cons #'epa-file-passphrase-callback-function
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local-file))
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(epg-context-set-progress-callback context
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#'epa-progress-callback-function)
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(unwind-protect
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(progn
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(if replace
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(goto-char (point-min)))
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(condition-case error
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(setq string (epg-decrypt-file context local-file nil))
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(error
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(if (setq entry (assoc file epa-file-passphrase-alist))
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(setcdr entry nil))
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(signal 'file-error
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(cons "Opening input file" (cdr error)))))
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(make-local-variable 'epa-file-encrypt-to)
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(setq epa-file-encrypt-to
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(mapcar #'car (epg-context-result-for context 'encrypted-to)))
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(if (or beg end)
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(setq string (substring string (or beg 0) end)))
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(save-excursion
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(save-restriction
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(narrow-to-region (point) (point))
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(epa-file-decode-and-insert string file visit beg end replace)
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(setq length (- (point-max) (point-min))))
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(if replace
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(delete-region (point) (point-max)))
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(if visit
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(set-visited-file-modtime))))
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(if (and local-copy
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(file-exists-p local-copy))
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(delete-file local-copy)))
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(list file length)))
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(put 'insert-file-contents 'epa-file 'epa-file-insert-file-contents)
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(defun epa-file-write-region (start end file &optional append visit lockname
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mustbenew)
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(if append
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(error "Can't append to the file."))
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(setq file (expand-file-name file))
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(let* ((coding-system (or coding-system-for-write
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(if (fboundp 'select-safe-coding-system)
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;; This is needed since Emacs 22 has
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;; no-conversion setting for *.gpg in
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;; `auto-coding-alist'.
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(let ((buffer-file-name
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(file-name-sans-extension file)))
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(select-safe-coding-system
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(point-min) (point-max)))
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buffer-file-coding-system)))
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(context (epg-make-context))
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(coding-system-for-write 'binary)
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string entry
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(recipients
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(cond
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((listp epa-file-encrypt-to) epa-file-encrypt-to)
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((stringp epa-file-encrypt-to) (list epa-file-encrypt-to)))))
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(epg-context-set-passphrase-callback
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context
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(cons #'epa-file-passphrase-callback-function
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file))
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(epg-context-set-progress-callback context
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#'epa-progress-callback-function)
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(epg-context-set-armor context epa-armor)
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(condition-case error
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(setq string
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(epg-encrypt-string
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context
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(if (stringp start)
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(epa-file--encode-coding-string start coding-system)
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(unless start
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(setq start (point-min)
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end (point-max)))
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(epa-file--encode-coding-string (buffer-substring start end)
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coding-system))
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(if (or epa-file-select-keys
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(not (local-variable-p 'epa-file-encrypt-to
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(current-buffer))))
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(epa-select-keys
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context
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"Select recipents for encryption.
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If no one is selected, symmetric encryption will be performed. "
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recipients)
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(if epa-file-encrypt-to
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(epg-list-keys context recipients)))))
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(error
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(if (setq entry (assoc file epa-file-passphrase-alist))
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(setcdr entry nil))
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(signal 'file-error (cons "Opening output file" (cdr error)))))
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(epa-file-run-real-handler
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#'write-region
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(list string nil file append visit lockname mustbenew))
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(if (boundp 'last-coding-system-used)
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(setq last-coding-system-used coding-system))
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(if (eq visit t)
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(progn
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(setq buffer-file-name file)
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(set-visited-file-modtime))
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(if (stringp visit)
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(progn
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(set-visited-file-modtime)
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(setq buffer-file-name visit))))
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(if (or (eq visit t)
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(eq visit nil)
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(stringp visit))
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(message "Wrote %s" buffer-file-name))))
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(put 'write-region 'epa-file 'epa-file-write-region)
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(defun epa-file-select-keys ()
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"Select recipients for encryption."
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(interactive)
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(make-local-variable 'epa-file-encrypt-to)
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(setq epa-file-encrypt-to
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(mapcar
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(lambda (key)
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(epg-sub-key-id (car (epg-key-sub-key-list key))))
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(epa-select-keys
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(epg-make-context)
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"Select recipents for encryption.
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If no one is selected, symmetric encryption will be performed. "))))
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;;;###autoload
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(defun epa-file-enable ()
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(interactive)
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(if (memq epa-file-handler file-name-handler-alist)
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(message "`epa-file' already enabled")
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(setq file-name-handler-alist
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(cons epa-file-handler file-name-handler-alist))
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(add-hook 'find-file-hook 'epa-file-find-file-hook)
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(setq auto-mode-alist (cons epa-file-auto-mode-alist-entry auto-mode-alist))
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(message "`epa-file' enabled")))
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;;;###autoload
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(defun epa-file-disable ()
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(interactive)
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(if (memq epa-file-handler file-name-handler-alist)
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(progn
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(setq file-name-handler-alist
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(delq epa-file-handler file-name-handler-alist))
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(remove-hook 'find-file-hook 'epa-file-find-file-hook)
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(setq auto-mode-alist (delq epa-file-auto-mode-alist-entry
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auto-mode-alist))
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(message "`epa-file' disabled"))
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(message "`epa-file' already disabled")))
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(provide 'epa-file)
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;; arch-tag: 5715152f-0eb1-4dbc-9008-07098775314d
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;;; epa-file.el ends here
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