Signal error and specify name

- desktop-registry.el (desktop-registry-add-directory): Add an optional
  NAME parameter which will be asked for (in an interactive context)
  when the universal argument is used. Print a message if the specified
  directory has already been registered, signal an error when the (given
  or generated) name has already been used and only add the directory if
  neither of these conditions occur.

  (desktop-registry-add-current-desktop): Add optional NAME parameter
  which will be asked for (in an interactive context) when the universal
  argument is used and pass it on to `desktop-registry-add-directory'.

1 files changed, 22 insertions, 12 deletions

diff --git a/desktop-registry.el b/desktop-registry.el
index 5206b96..ba35d16 100644
--- a/desktop-registry.el
+++ b/desktop-registry.el
@@ -60,23 +60,33 @@ Returns DEFAULT when `desktop-dirname' is nil."
     default))
 
 ;;;###autoload
-(defun desktop-registry-add-directory (dir)
-  "Add DIR to the desktop registry."
-  (interactive "DDirectory: ")
+(defun desktop-registry-add-directory (dir &optional name)
+  "Add DIR to the desktop registry, possibly using NAME."
+  (interactive (list (read-directory-name "Directory: ")
+                     (if (equal current-prefix-arg '(4))
+                         (read-string "Name: "))))
   (let* ((clean-dir (desktop-registry--canonicalize-dir dir))
-         (label (file-name-base clean-dir)))
-    (unless (assoc label desktop-registry-registry)
-      (customize-save-variable
-       'desktop-registry-registry
-       (cons (cons label clean-dir) desktop-registry-registry)))))
+         (label (or name (file-name-base clean-dir))))
+    (cond
+     ((cl-find clean-dir desktop-registry-registry
+               :key 'cdr :test 'equal)
+      (message "Directory %s already registered" clean-dir))
+     ((cl-find label desktop-registry-registry :key 'car :test 'equal)
+      (error "Name %s already used" label))
+     (t (customize-save-variable
+         'desktop-registry-registry
+         (cons (cons label clean-dir) desktop-registry-registry))))))
 
 ;;;###autoload
-(defun desktop-registry-add-current-desktop ()
-  "Add the currently opened desktop file to `desktop-registry-registry'."
-  (interactive)
+(defun desktop-registry-add-current-desktop (&optional name)
+  "Add the currently opened desktop file to `desktop-registry-registry'.
+
+If NAME is specified use that as the name for the registry entry."
+  (interactive (list (if (equal current-prefix-arg '(4))
+                         (read-string "Name: "))))
   (unless desktop-dirname
     (error "No desktop loaded"))
-  (desktop-registry-add-directory desktop-dirname))
+  (desktop-registry-add-directory desktop-dirname name))
 
 (defun desktop-registry--completing-read (&optional prompt
                                                     default-current)