Revive plstore editing mode previously reverted due to feature freeze.

2 files changed, 139 insertions, 6 deletions

diff --git a/lisp/gnus/ChangeLog b/lisp/gnus/ChangeLog
index 52f140d9192..be4d0675781 100644
--- a/lisp/gnus/ChangeLog
+++ b/lisp/gnus/ChangeLog
@@ -1,3 +1,13 @@
+2012-04-26  Daiki Ueno  <ueno@unixuser.org>
+
+        * plstore.el: Revive the editing feature.
+        (plstore-mode): New mode to edit plstore file.
+        (plstore-mode-toggle-display, plstore-mode-original)
+        (plstore-mode-decoded): New command.
+        (plstore--encode, plstore--decode, plstore--write-contents-functions)
+        (plstore--insert-buffer, plstore--make): New function.
+        (plstore-open, plstore-save): Simplify by using them.
+
 2012-04-16  Glenn Morris  <rgm@gnu.org>
 
         * nndraft.el (nndraft-request-list): Fix declaration.
diff --git a/lisp/gnus/plstore.el b/lisp/gnus/plstore.el
index cbd5e2a3b0a..2f446c84071 100644
--- a/lisp/gnus/plstore.el
+++ b/lisp/gnus/plstore.el
@@ -64,8 +64,18 @@
 ;;
 ;; Editing:
 ;;
-;; Currently not supported but in the future plstore will provide a
-;; major mode to edit PLSTORE files.
+;; This file also provides `plstore-mode', a major mode for editing
+;; the PLSTORE format file.  Visit a non-existing file and put the
+;; following line:
+;;
+;; (("foo" :host "foo.example.org" :secret-user "user"))
+;;
+;; where the prefixing `:secret-' means the property (without
+;; `:secret-' prefix) is marked as secret.  Thus, when you save the
+;; buffer, the `:secret-user' property is encrypted as `:user'.
+;;
+;; You can toggle the view between encrypted form and the decrypted
+;; form with C-c C-c.
 
 ;;; Code:
 
@@ -107,6 +117,10 @@ symmetric encryption will be used.")
 
 (put 'plstore-encrypt-to 'permanent-local t)
 
+(defvar plstore-encoded nil)
+
+(put 'plstore-encoded 'permanent-local t)
+
 (defvar plstore-cache-passphrase-for-symmetric-encryption nil)
 (defvar plstore-passphrase-alist nil)
 
@@ -194,10 +208,6 @@ symmetric encryption will be used.")
                      (generate-new-buffer (format " plstore %s" filename))))
          (store (plstore--make buffer)))
     (with-current-buffer buffer
-      ;; In the future plstore will provide a major mode called
-      ;; `plstore-mode' to edit PLSTORE files.
-      (if (eq major-mode 'plstore-mode)
-          (error "%s is opened for editing; kill the buffer first" file))
       (erase-buffer)
       (condition-case nil
           (insert-file-contents-literally file)
@@ -435,6 +445,119 @@ If no one is selected, symmetric encryption will be performed.  "
     (plstore--insert-buffer plstore)
     (save-buffer)))
 
+(defun plstore--encode (plstore)
+  (plstore--decrypt plstore)
+  (let ((merged-alist (plstore--get-merged-alist plstore)))
+    (concat "("
+            (mapconcat
+             (lambda (entry)
+               (setq entry (copy-sequence entry))
+               (let ((merged-plist (cdr (assoc (car entry) merged-alist)))
+                     (plist (cdr entry)))
+                 (while plist
+                   (if (string-match "\\`:secret-" (symbol-name (car plist)))
+                       (setcar (cdr plist)
+                               (plist-get
+                                merged-plist
+                                (intern (concat ":"
+                                                (substring (symbol-name
+                                                            (car plist))
+                                                           (match-end 0)))))))
+                   (setq plist (nthcdr 2 plist)))
+                 (prin1-to-string entry)))
+             (plstore--get-alist plstore)
+             "\n")
+            ")")))
+
+(defun plstore--decode (string)
+  (let* ((alist (car (read-from-string string)))
+         (pointer alist)
+         secret-alist
+         plist
+         entry)
+    (while pointer
+      (unless (stringp (car (car pointer)))
+        (error "Invalid PLSTORE format %s" string))
+      (setq plist (cdr (car pointer)))
+      (while plist
+        (when (string-match "\\`:secret-" (symbol-name (car plist)))
+          (setq entry (assoc (car (car pointer)) secret-alist))
+          (unless entry
+            (setq entry (list (car (car pointer)))
+                  secret-alist (cons entry secret-alist)))
+          (setcdr entry (plist-put (cdr entry)
+                                   (intern (concat ":"
+                                                (substring (symbol-name
+                                                            (car plist))
+                                                           (match-end 0))))
+                                   (car (cdr plist))))
+          (setcar (cdr plist) t))
+        (setq plist (nthcdr 2 plist)))
+      (setq pointer (cdr pointer)))
+    (plstore--make nil alist nil secret-alist)))
+
+(defun plstore--write-contents-functions ()
+  (when plstore-encoded
+    (let ((store (plstore--decode (buffer-string)))
+          (file (buffer-file-name)))
+      (unwind-protect
+          (progn
+            (set-visited-file-name nil)
+            (with-temp-buffer
+              (plstore--insert-buffer store)
+              (write-region (buffer-string) nil file)))
+        (set-visited-file-name file)
+        (set-buffer-modified-p nil))
+      t)))
+
+(defun plstore-mode-original ()
+  "Show the original form of the this buffer."
+  (interactive)
+  (when plstore-encoded
+    (if (and (buffer-modified-p)
+             (y-or-n-p "Save buffer before reading the original form? "))
+        (save-buffer))
+    (erase-buffer)
+    (insert-file-contents-literally (buffer-file-name))
+    (set-buffer-modified-p nil)
+    (setq plstore-encoded nil)))
+
+(defun plstore-mode-decoded ()
+  "Show the decoded form of the this buffer."
+  (interactive)
+  (unless plstore-encoded
+    (if (and (buffer-modified-p)
+             (y-or-n-p "Save buffer before decoding? "))
+        (save-buffer))
+    (let ((store (plstore--make (current-buffer))))
+      (plstore--init-from-buffer store)
+      (erase-buffer)
+      (insert
+       (substitute-command-keys "\
+;;; You are looking at the decoded form of the PLSTORE file.\n\
+;;; To see the original form content, do \\[plstore-mode-toggle-display]\n\n"))
+      (insert (plstore--encode store))
+      (set-buffer-modified-p nil)
+      (setq plstore-encoded t))))
+
+(defun plstore-mode-toggle-display ()
+  "Toggle the display mode of PLSTORE between the original and decoded forms."
+  (interactive)
+  (if plstore-encoded
+      (plstore-mode-original)
+    (plstore-mode-decoded)))
+
+;;;###autoload
+(define-derived-mode plstore-mode emacs-lisp-mode "PLSTORE"
+  "Major mode for editing PLSTORE files."
+  (make-local-variable 'plstore-encoded)
+  (add-hook 'write-contents-functions #'plstore--write-contents-functions)
+  (define-key plstore-mode-map "\C-c\C-c" #'plstore-mode-toggle-display)
+  ;; to create a new file with plstore-mode, mark it as already decoded
+  (if (called-interactively-p 'any)
+      (setq plstore-encoded t)
+    (plstore-mode-decoded)))
+
 (provide 'plstore)
 
 ;;; plstore.el ends here