Add public key encryption support to plstore.

* plstore.el (plstore-select-keys, plstore-encrypt-to): New variable.
(plstore-save): Support public key encryption.
(plstore--init-from-buffer): New function.
(plstore-open): Use it; fix error when opening a non-existent file.
(plstore-revert): Use plstore--init-from-buffer.

diff --git a/lisp/gnus/ChangeLog b/lisp/gnus/ChangeLog
index bd7c81f56249b5a333e2c390f5b17edf4509c66a..50082d6039bcee46a22bcbfdab3599a4af1f8144 100644 (file)
--- a/lisp/gnus/ChangeLog
+++ b/lisp/gnus/ChangeLog
@@ -1,3 +1,11 @@
+2011-07-01  Daiki Ueno  <ueno@unixuser.org>
+
+       * plstore.el (plstore-select-keys, plstore-encrypt-to): New variable.
+       (plstore-save): Support public key encryption.
+       (plstore--init-from-buffer): New function.
+       (plstore-open): Use it; fix error when opening a non-existent file.
+       (plstore-revert): Use plstore--init-from-buffer.
+
 2011-07-01  Daiki Ueno  <ueno@unixuser.org>
 
        * auth-source.el (auth-source-backend): Fix :initarg for data slot.

diff --git a/lisp/gnus/plstore.el b/lisp/gnus/plstore.el
index 392437d1dea8714ea438992b83914b63c4d362a2..8111c4c226ea903d78806df76c9b9d27c6f89a78 100644 (file)
--- a/lisp/gnus/plstore.el
+++ b/lisp/gnus/plstore.el
@@ -44,6 +44,40 @@
 
 (require 'epg)
 
+(defgroup plstore nil
+  "Searchable, partially encrypted, persistent plist store"
+  :version "24.1"
+  :group 'files)
+
+(defcustom plstore-select-keys 'silent
+  "Control whether or not to pop up the key selection dialog.
+
+If t, always asks user to select recipients.
+If nil, query user only when `plstore-encrypt-to' is not set.
+If neither t nor nil, doesn't ask user.  In this case, symmetric
+encryption is used."
+  :type '(choice (const :tag "Ask always" t)
+                (const :tag "Ask when recipients are not set" nil)
+                (const :tag "Don't ask" silent))
+  :group 'plstore)
+
+(defvar plstore-encrypt-to nil
+  "*Recipient(s) used for encrypting secret entries.
+May either be a string or a list of strings.")
+
+(put 'plstore-encrypt-to 'safe-local-variable
+     (lambda (val)
+       (or (stringp val)
+          (and (listp val)
+               (catch 'safe
+                 (mapc (lambda (elt)
+                         (unless (stringp elt)
+                           (throw 'safe nil)))
+                       val)
+                 t)))))
+
+(put 'plstore-encrypt-to 'permanent-local t)
+
 (defvar plstore-cache-passphrase-for-symmetric-encryption nil)
 (defvar plstore-passphrase-alist nil)
 
@@ -107,35 +141,39 @@
 (defun plstore-get-file (this)
   (buffer-file-name (plstore--get-buffer this)))
 
+(defun plstore--init-from-buffer (plstore)
+  (goto-char (point-min))
+  (when (looking-at ";;; public entries\n")
+    (forward-line)
+    (plstore--set-alist plstore (read (point-marker)))
+    (forward-sexp)
+    (forward-char)
+    (when (looking-at ";;; secret entries\n")
+      (forward-line)
+      (plstore--set-encrypted-data plstore (read (point-marker))))
+    (plstore--merge-secret plstore)))
+
 ;;;###autoload
 (defun plstore-open (file)
   "Create a plstore instance associated with FILE."
-  (let ((store (vector
-               (find-file-noselect file)
-               nil                  ;plist (plist)
-               nil                  ;encrypted data (string)
-               nil                  ;secret plist (plist)
-               nil                  ;merged plist (plist)
-               )))
-    (plstore-revert store)
-    store))
+  (with-current-buffer (find-file-noselect file)
+    ;; make the buffer invisible from user
+    (rename-buffer (format " plstore %s" (buffer-file-name)))
+    (let ((store (vector
+                 (current-buffer)
+                 nil                ;plist (plist)
+                 nil                ;encrypted data (string)
+                 nil                ;secret plist (plist)
+                 nil                ;merged plist (plist)
+                 )))
+      (plstore--init-from-buffer store)
+      store)))
 
 (defun plstore-revert (plstore)
   "Replace current data in PLSTORE with the file on disk."
   (with-current-buffer (plstore--get-buffer plstore)
     (revert-buffer t t)
-    ;; make the buffer invisible from user
-    (rename-buffer (format " plstore %s" (buffer-file-name)))
-    (goto-char (point-min))
-    (when (looking-at ";;; public entries\n")
-      (forward-line)
-      (plstore--set-alist plstore (read (point-marker)))
-      (forward-sexp)
-      (forward-char)
-      (when (looking-at ";;; secret entries\n")
-       (forward-line)
-       (plstore--set-encrypted-data plstore (read (point-marker))))
-      (plstore--merge-secret plstore))))
+    (plstore--init-from-buffer plstore)))
 
 (defun plstore-close (plstore)
   "Destroy a plstore instance PLSTORE."
@@ -304,20 +342,36 @@ SECRET-KEYS is a plist containing secret data."
   "Save the contents of PLSTORE associated with a FILE."
   (with-current-buffer (plstore--get-buffer plstore)
     (erase-buffer)
-    (insert ";;; public entries\n" (pp-to-string (plstore--get-alist plstore)))
+    (insert ";;; public entries -*- mode: emacs-lisp -*- \n"
+           (pp-to-string (plstore--get-alist plstore)))
     (if (plstore--get-secret-alist plstore)
        (let ((context (epg-make-context 'OpenPGP))
              (pp-escape-newlines nil)
+             (recipients
+              (cond
+               ((listp plstore-encrypt-to) plstore-encrypt-to)
+               ((stringp plstore-encrypt-to) (list plstore-encrypt-to))))
              cipher)
          (epg-context-set-armor context t)
          (epg-context-set-passphrase-callback
           context
           (cons #'plstore-passphrase-callback-function
                 plstore))
-         (setq cipher (epg-encrypt-string context
-                                          (pp-to-string
-                                           (plstore--get-secret-alist plstore))
-                                          nil))
+         (setq cipher (epg-encrypt-string
+                       context
+                       (pp-to-string
+                        (plstore--get-secret-alist plstore))
+                       (if (or (eq plstore-select-keys t)
+                               (and (null plstore-select-keys)
+                                    (not (local-variable-p 'plstore-encrypt-to
+                                                           (current-buffer)))))
+                           (epa-select-keys
+                            context
+                            "Select recipents for encryption.
+If no one is selected, symmetric encryption will be performed.  "
+                            recipients)
+                         (if plstore-encrypt-to
+                             (epg-list-keys context recipients)))))
          (insert ";;; secret entries\n" (pp-to-string cipher))))
     (save-buffer)))