[Emacs-diffs] trunk r116999: Provide function for asking vc about project root

[Daniel Colascione]

------------------------------------------------------------
revno: 116999
revision-id: address@hidden
parent: address@hidden
committer: Daniel Colascione <address@hidden>
branch nick: trunk
timestamp: Sun 2014-04-20 16:24:04 -0700
message:
  Provide function for asking vc about project root
modified:
  lisp/ChangeLog                 changelog-20091113204419-o5vbwnq5f7feedwu-1432
  lisp/vc/vc-hooks.el            vchooks.el-20091113204419-o5vbwnq5f7feedwu-501
  lisp/vc/vc.el                  vc.el-20091113204419-o5vbwnq5f7feedwu-502

=== modified file 'lisp/ChangeLog'
--- a/lisp/ChangeLog    2014-04-20 02:34:22 +0000
+++ b/lisp/ChangeLog    2014-04-20 23:24:04 +0000
@@ -1,5 +1,13 @@
 2014-04-20  Daniel Colascione  <address@hidden>
 
+       * vc/vc.el (vc-root-dir): New public autoloaded function for
+       generically finding the current VC root.
+       * vc/vc-hooks.el (vc-not-supported): New error.
+       (vc-call-backend): Signal `vc-not-supported' instead of generic
+       error.
+
+2014-04-20  Daniel Colascione  <address@hidden>
+
        * emacs-lisp/cl-macs.el (cl-the): Make `cl-the' assert its type
        argument.
        (cl--const-expr-val): cl--const-expr-val should macroexpand its

=== modified file 'lisp/vc/vc-hooks.el'
--- a/lisp/vc/vc-hooks.el       2014-01-01 07:43:34 +0000
+++ b/lisp/vc/vc-hooks.el       2014-04-20 23:24:04 +0000
@@ -190,6 +190,11 @@
 (make-variable-buffer-local 'vc-mode)
 (put 'vc-mode 'permanent-local t)
 
+;;; We signal this error when we try to do something a VC backend
+;;; doesn't support.  Two arguments: the method that's not supported
+;;; and the backend
+(define-error 'vc-not-supported "VC method not implemented for backend")
+
 (defun vc-mode (&optional _arg)
   ;; Dummy function for C-h m
   "Version Control minor mode.
@@ -268,10 +273,10 @@
       (setq f (vc-find-backend-function backend function-name))
       (push (cons function-name f) (get backend 'vc-functions)))
     (cond
-     ((null f)
-      (error "Sorry, %s is not implemented for %s" function-name backend))
-     ((consp f)        (apply (car f) (cdr f) args))
-     (t                (apply f args)))))
+      ((null f)
+       (signal 'vc-not-supported (list function-name backend)))
+      ((consp f)       (apply (car f) (cdr f) args))
+      (t               (apply f args)))))
 
 (defmacro vc-call (fun file &rest args)
   "A convenience macro for calling VC backend functions.

=== modified file 'lisp/vc/vc.el'
--- a/lisp/vc/vc.el     2014-03-23 18:13:35 +0000
+++ b/lisp/vc/vc.el     2014-04-20 23:24:04 +0000
@@ -1879,6 +1879,19 @@
         (called-interactively-p 'interactive))))))
 
 ;;;###autoload
+(defun vc-root-dir ()
+  "Return the root directory for the current VC tree.
+Return nil if the root directory cannot be identified."
+  (let ((backend (vc-deduce-backend)))
+    (if backend
+        (condition-case err
+            (vc-call-backend backend 'root default-directory)
+          (vc-not-supported
+           (unless (eq (cadr err) 'root)
+             (signal (car err) (cdr err)))
+           nil)))))
+
+;;;###autoload
 (defun vc-revision-other-window (rev)
   "Visit revision REV of the current file in another window.
 If the current file is named `F', the revision is named `F.~REV~'.