Add use of algorithm switch

DisPass has supported more than one algorithm for some time already,
but how to specify which algorithm to use was not quite clear. Now it
should use the correct algorithm and when specifying an unknown label
it will ask for the preferred algorithm.

dispass.el

@@ -63,6 +63,11 @@
   "Keymap for `dispass-labels-mode', uses
   `tabulated-list-mode-map' as its parent.")
 
+(defconst dispass-algorithms
+  '("dispass1" "dispass2")
+  "The list of algorithms supported by DisPass, this should be
+  extracted from DisPass at some point.")
+
 (defun dispass-process-sentinel (proc status)
   "Report PROC's status change to STATUS."
   (let ((status (substring status 0 -1))
@@ -106,12 +111,12 @@ an eye out for LABEL."
                 (clipboard-kill-ring-save (point-min) (point-max))
                 (message "Password copied to clipboard.")))))))
 
-(defun dispass-start-process (label create length)
+(defun dispass-start-process (label create length &optional algo args)
   "Start dispass process.  When CREATE is non-nil send along the
   -c switch to make it ask for a password twice.  When LENGTH is
   an integer and greater than 0, send along the -l switch with
   LENGTH."
-  (let ((args `("-o" ,label))
+  (let ((args `("-o" ,@args ,label))
         proc)
     (when create
       (setq args (append '("-c") args)))
@@ -119,6 +124,10 @@ an eye out for LABEL."
     (when (and (integerp length) (> length 0))
       (setq args (append `("-l" ,(number-to-string length)) args)))
 
+    (when (and algo (not (equal algo ""))
+               (member algo dispass-algorithms))
+      (setq args (append `("-a" ,algo) args)))
+
     (setq proc (apply 'start-process "dispass" "*dispass*"
                       dispass-executable args))
     (set-process-sentinel proc 'dispass-process-sentinel)
@@ -128,9 +137,18 @@ an eye out for LABEL."
   "Get the list of labels and their information."
   (let ((result '()))
     (with-temp-buffer
-      (insert (shell-command-to-string
-               (concat dispass-labels-executable " -l --script")))
-      (goto-char (point-min))
+      (dispass-read-labels)
+      (while (re-search-forward
+              "^\\(\\(?:\\sw\\|\\s_\\)+\\)"
+              nil t)
+        (add-to-list 'result (match-string 1)))
+      result)))
+
+(defun dispass-get-labels-for-display ()
+  "Prepare the list of labels for info table."
+  (let ((result '()))
+    (with-temp-buffer
+      (dispass-read-labels)
       (while (re-search-forward
               "^\\(\\(?:\\sw\\|\\s_\\)+\\) +\\([0-9]+\\) +\\(\\(?:\\sw\\|\\s_\\)+\\)"
               nil t)
@@ -150,23 +168,37 @@ an eye out for LABEL."
                             ,algo])))))
     result))
 
-;;;###autoload
-(defun dispass-create (label &optional length)
-  "Create a new password for LABEL."
-  (interactive "MLabel: \nP")
-  (let ((length (or length dispass-default-length)))
-    (dispass-start-process label t length)))
+(defun dispass-read-labels ()
+  "Load a list of all labels into a buffer."
+  (insert (shell-command-to-string
+           (concat dispass-labels-executable " -l --script")))
+  (goto-char (point-min)))
 
 ;;;###autoload
-(defun dispass (label &optional length)
+(defun dispass-create (label &optional length algo)
+  "Create a new password for LABEL."
+  (interactive (list
+                (read-from-minibuffer "Label: ")
+                current-prefix-arg
+                (completing-read "Algorithm: " dispass-algorithms)))
+  (let ((length (or length dispass-default-length)))
+    (dispass-start-process label t length algo)))
+
+;;;###autoload
+(defun dispass (label &optional length algo)
   "Recreate a password previously used."
   (interactive (list
                 (completing-read
-                 "Label: " (mapcar (lambda (elm) (elt elm 0))
-                                   (dispass-get-labels)))
+                 "Label: " (dispass-get-labels))
                 current-prefix-arg))
+  (if (called-interactively-p 'any)
+      (unless (member label (dispass-get-labels))
+        (setq algo (completing-read
+                         "Algorithm: " dispass-algorithms))))
   (let ((length (or length dispass-default-length)))
-    (dispass-start-process label nil length)))
+    (dispass-start-process
+     label nil length algo
+     (when (member label (dispass-get-labels)) '("-s")))))
 
 ;; Labels management
 ;;;###autoload
@@ -177,10 +209,12 @@ an eye out for LABEL."
          (read-from-minibuffer
           (format "Length (%d): " dispass-default-length) nil nil t nil
           (number-to-string dispass-default-length))
-         (symbol-name (read-from-minibuffer
-                       "Algorithm (dispass1): " nil nil t nil "dispass1"))))
+         (completing-read
+          "Algorithm (dispass1): "
+          dispass-algorithms nil nil nil nil "dispass1")))
   (shell-command
-   (format "%s --add %s:%d:%s" dispass-labels-executable label length algo)))
+   (format "%s --add %s:%d:%s"
+           dispass-labels-executable label length algo)))
 
 ;;;###autoload
 (defun dispass-remove-label (label)
@@ -191,9 +225,7 @@ thrown."
   (interactive
    (list (or (dispass-label-at-point)
              (completing-read
-              "Label: " (mapcar (lambda (elm) (elt elm 0))
-                                (dispass-get-labels))))))
-
+              "Label: " (dispass-get-labels)))))
   (shell-command
    (format "%s --remove %s" dispass-labels-executable label)))
 
@@ -207,7 +239,7 @@ thrown."
   (setq tabulated-list-entries nil)
 
   (let ((tmp-list '()))
-    (setq tabulated-list-entries (dispass-get-labels))))
+    (setq tabulated-list-entries (dispass-get-labels-for-display))))
 
 (define-derived-mode dispass-labels-mode tabulated-list-mode "DisPass"
   "Major mode for listing dispass labels.