* epa-file.el (epa-file-passphrase-callback-function): Use
[elisp/epg.git] / epa-file.el
index a924aa7..551a7a0 100644 (file)
@@ -13,7 +13,7 @@
 
 ;; 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
+;; 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
   "The EasyPG Assistant hooks for transparent file encryption"
   :group 'epa)
 
-(defcustom epa-file-name-regexp "\\.gpg\\'"
-  "Regexp which matches filenames to be encrypted with GnuPG."
+(defun epa-file--file-name-regexp-set (variable value)
+  (set-default variable value)
+  (if (fboundp 'epa-file-name-regexp-update)
+      (epa-file-name-regexp-update)))
+
+(defcustom epa-file-name-regexp "\\.gpg\\(~\\|\\.~[0-9]+~\\)?\\'"
+  "Regexp which matches filenames to be encrypted with GnuPG.
+
+If you set this outside Custom while epa-file is already enabled, you
+have to call `epa-file-name-regexp-update' after setting it to
+properly update file-name-handler-alist.  Setting this through Custom
+does that automatically."
   :type 'regexp
-  :group 'epa-file)
+  :group 'epa-file
+  :set 'epa-file--file-name-regexp-set)
 
 (defcustom epa-file-cache-passphrase-for-symmetric-encryption nil
-  "If t, cache passphrase for symmetric encryption."
+  "If non-nil, cache passphrase for symmetric encryption."
+  :type 'boolean
+  :group 'epa-file)
+
+(defcustom epa-file-inhibit-auto-save t
+  "If non-nil, disable auto-saving when opening an encrypted file."
+  :type 'boolean
+  :group 'epa-file)
+
+(defcustom epa-file-select-keys nil
+  "If non-nil, always asks user to select recipients."
   :type 'boolean
   :group 'epa-file)
 
@@ -55,26 +76,50 @@ May either be a string or a list of strings.")
                        val)
                  t)))))
 
+;;;###autoload
+(put 'epa-file-encrypt-to 'permanent-local t)
+
 (defvar epa-file-handler
   (cons epa-file-name-regexp 'epa-file-handler))
 
+(defvar epa-file-auto-mode-alist-entry
+  (list epa-file-name-regexp nil 'epa-file))
+
 (defvar epa-file-passphrase-alist nil)
 
+(eval-and-compile
+  (if (fboundp 'encode-coding-string)
+      (defalias 'epa-file--encode-coding-string 'encode-coding-string)
+    (defalias 'epa-file--encode-coding-string 'identity)))
+
+(eval-and-compile
+  (if (fboundp 'decode-coding-string)
+      (defalias 'epa-file--decode-coding-string 'decode-coding-string)
+    (defalias 'epa-file--decode-coding-string 'identity)))
+
+(defun epa-file-name-regexp-update ()
+  (interactive)
+  (unless (equal (car epa-file-handler) epa-file-name-regexp)
+    (setcar epa-file-handler epa-file-name-regexp)))
+
 (defun epa-file-passphrase-callback-function (context key-id file)
   (if (and epa-file-cache-passphrase-for-symmetric-encryption
           (eq key-id 'SYM))
-      (let ((entry (assoc file epa-file-passphrase-alist))
-           passphrase)
-       (or (copy-sequence (cdr entry))
-           (progn
-             (unless entry
-               (setq entry (list file)
-                     epa-file-passphrase-alist (cons entry
-                                                epa-file-passphrase-alist)))
-             (setq passphrase (epa-passphrase-callback-function context
-                                                                key-id nil))
-             (setcdr entry (copy-sequence passphrase))
-             passphrase)))
+      (progn
+       (setq file (file-truename file))
+       (let ((entry (assoc file epa-file-passphrase-alist))
+             passphrase)
+         (or (copy-sequence (cdr entry))
+             (progn
+               (unless entry
+                 (setq entry (list file)
+                       epa-file-passphrase-alist
+                       (cons entry
+                             epa-file-passphrase-alist)))
+               (setq passphrase (epa-passphrase-callback-function context
+                                                                  key-id nil))
+               (setcdr entry (copy-sequence passphrase))
+               passphrase))))
     (epa-passphrase-callback-function context key-id nil)))
 
 (defun epa-file-handler (operation &rest args)
@@ -104,8 +149,8 @@ May either be a string or a list of strings.")
           (point-min) (point-max)
           (substring file 0 (string-match epa-file-name-regexp file))
           visit beg end replace)))
-    (insert (decode-coding-string string (or coding-system-for-read
-                                            'undecided)))))
+    (insert (epa-file--decode-coding-string string (or coding-system-for-read
+                                                      'undecided)))))
 
 (defvar last-coding-system-used)
 (defun epa-file-insert-file-contents (file &optional visit beg end replace)
@@ -113,15 +158,19 @@ May either be a string or a list of strings.")
   (if (and visit (or beg end))
       (error "Attempt to visit less than an entire file"))
   (setq file (expand-file-name file))
-  (let ((local-copy (epa-file-run-real-handler #'file-local-copy (list file)))
-       (context (epg-make-context))
-       string length entry)
+  (let* ((local-copy
+         (condition-case inl
+             (epa-file-run-real-handler #'file-local-copy (list file))
+           (error)))
+        (local-file (or local-copy file))
+        (context (epg-make-context))
+        string length entry)
     (if visit
        (setq buffer-file-name file))
     (epg-context-set-passphrase-callback
      context
      (cons #'epa-file-passphrase-callback-function
-          file))
+          local-file))
     (epg-context-set-progress-callback context
                                       #'epa-progress-callback-function)
     (unwind-protect
@@ -129,12 +178,15 @@ May either be a string or a list of strings.")
          (if replace
              (goto-char (point-min)))
          (condition-case error
-             (setq string (epg-decrypt-file context file nil))
+             (setq string (epg-decrypt-file context local-file nil))
            (error
             (if (setq entry (assoc file epa-file-passphrase-alist))
                 (setcdr entry nil))
             (signal 'file-error
                     (cons "Opening input file" (cdr error)))))
+         (make-local-variable 'epa-file-encrypt-to)
+         (setq epa-file-encrypt-to
+               (mapcar #'car (epg-context-result-for context 'encrypted-to)))
          (if (or beg end)
              (setq string (substring string (or beg 0) end)))
          (save-excursion
@@ -156,36 +208,47 @@ May either be a string or a list of strings.")
       (error "Can't append to the file."))
   (setq file (expand-file-name file))
   (let* ((coding-system (or coding-system-for-write
-                           (if (boundp 'last-coding-system-used)
-                               (condition-case nil
-                                   (write-region (point-min) (point-max) "/")
-                                 (error last-coding-system-used))
+                           (if (fboundp 'select-safe-coding-system)
+                               ;; This is needed since Emacs 22 has
+                               ;; no-conversion setting for *.gpg in
+                               ;; `auto-coding-alist'.
+                               (let ((buffer-file-name
+                                      (file-name-sans-extension file)))
+                                 (select-safe-coding-system
+                                  (point-min) (point-max)))
                              buffer-file-coding-system)))
         (context (epg-make-context))
         (coding-system-for-write 'binary)
-        string entry)
+        string entry
+        (recipients
+         (cond
+          ((listp epa-file-encrypt-to) epa-file-encrypt-to)
+          ((stringp epa-file-encrypt-to) (list epa-file-encrypt-to)))))
     (epg-context-set-passphrase-callback
      context
      (cons #'epa-file-passphrase-callback-function
           file))
     (epg-context-set-progress-callback context
                                       #'epa-progress-callback-function)
+    (epg-context-set-armor context epa-armor)
     (condition-case error
        (setq string
              (epg-encrypt-string
               context
               (if (stringp start)
-                  (encode-coding-string start coding-system)
-                (encode-coding-string (buffer-substring start end)
-                                      coding-system))
-              (unless (assoc file epa-file-passphrase-alist)
-                (epa-select-keys
-                 context
-                 "Select recipents for encryption.
+                  (epa-file--encode-coding-string start coding-system)
+                (epa-file--encode-coding-string (buffer-substring start end)
+                                                coding-system))
+              (if (or epa-file-select-keys
+                      (not (local-variable-p 'epa-file-encrypt-to
+                                             (current-buffer))))
+                  (epa-select-keys
+                   context
+                   "Select recipents for encryption.
 If no one is selected, symmetric encryption will be performed.  "
-                 (cond
-                  ((listp epa-file-encrypt-to) epa-file-encrypt-to)
-                  ((stringp epa-file-encrypt-to) (list epa-file-encrypt-to)))))))
+                   recipients)
+                (if epa-file-encrypt-to
+                    (epg-list-keys context recipients)))))
       (error
        (if (setq entry (assoc file epa-file-passphrase-alist))
           (setcdr entry nil))
@@ -209,6 +272,23 @@ If no one is selected, symmetric encryption will be performed.  "
        (message "Wrote %s" buffer-file-name))))
 (put 'write-region 'epa-file 'epa-file-write-region)
 
+(defun epa-file-find-file-hook ()
+  (if (and buffer-file-name
+          (string-match epa-file-name-regexp buffer-file-name)
+          epa-file-inhibit-auto-save)
+      (auto-save-mode 0))
+  (set-buffer-modified-p nil))
+
+(defun epa-file-select-keys ()
+  "Select recipients for encryption."
+  (interactive)
+  (make-local-variable 'epa-file-encrypt-to)
+  (setq epa-file-encrypt-to
+       (epa-select-keys
+        (epg-make-context)
+        "Select recipents for encryption.
+If no one is selected, symmetric encryption will be performed.  ")))
+
 ;;;###autoload
 (defun epa-file-enable ()
   (interactive)
@@ -216,6 +296,8 @@ If no one is selected, symmetric encryption will be performed.  "
       (message "`epa-file' already enabled")
     (setq file-name-handler-alist
          (cons epa-file-handler file-name-handler-alist))
+    (add-hook 'find-file-hooks 'epa-file-find-file-hook)
+    (setq auto-mode-alist (cons epa-file-auto-mode-alist-entry auto-mode-alist))
     (message "`epa-file' enabled")))
 
 ;;;###autoload
@@ -225,6 +307,9 @@ If no one is selected, symmetric encryption will be performed.  "
       (progn
        (setq file-name-handler-alist
              (delq epa-file-handler file-name-handler-alist))
+       (remove-hook 'find-file-hooks 'epa-file-find-file-hook)
+       (setq auto-mode-alist (delq epa-file-auto-mode-alist-entry
+                                   auto-mode-alist))
        (message "`epa-file' disabled"))
     (message "`epa-file' already disabled")))