Autorevert: Add support for VC controlled files.

(eval-when-compile): Defvar dired-directory and vc-mode.
(auto-revert-vc-cvs-file-version, auto-revert-vc-buffer-p)
(auto-revert-handler-vc): New functions.

2 files changed, 78 insertions, 11 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c13e5dff431..88fa9377f46 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -5,13 +5,16 @@
 
 2004-02-16  Jari Aalto  <jari.aalto@poboxes.com>
 
-        Autorevert: Add support to detect changed dired buffers.
+        Autorevert: Add support to detect changed dired buffers and for
+        VC controlled files.
         * autorevert.el (auto-revert-active-p, auto-revert-list-diff)
         (auto-revert-dired-file-list, auto-revert-dired-changed-p)
         (auto-revert-handler, auto-revert-active-p): New functions.
         (auto-revert-buffers): Moved revert logic to `auto-revert-handler'
         and `auto-revert-active-p'.
-        (eval-when-compile): Defvar dired-directory.
+        (eval-when-compile): Defvar dired-directory and vc-mode.
+        (auto-revert-vc-cvs-file-version, auto-revert-vc-buffer-p)
+        (auto-revert-handler-vc): New functions.
 
 2004-02-16  Alfred M. Szmidt  <ams@kemisten.nu>  (tiny change)
 
diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index 309517476e1..a720e547b20 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -71,9 +71,12 @@
 
 (require 'timer)
 (autoload 'dired-get-filename "dired")
+(autoload 'vc-workfile-version "vc-hooks")
+(autoload 'vc-mode-line        "vc-hooks")
 
 (eval-when-compile
   (defvar dired-directory)
+  (defvar vc-mode)
   (require 'cl))
 
 
@@ -294,10 +297,13 @@ Use `auto-revert-mode' to revert a particular buffer."
 
 (defun auto-revert-buffer-p ()
   "Check if current buffer should be reverted."
-  ;;  Always include dired buffers to list. It would be too expensive
+  ;;  - Always include dired buffers to list. It would be too expensive
   ;;  to test the "revert" status here each time timer launches.
+  ;;  - Same for VC buffers.
   (or (eq major-mode 'dired-mode)
       (and (not (buffer-modified-p))
+           (auto-revert-vc-buffer-p))
+      (and (not (buffer-modified-p))
            (if (buffer-file-name)
                (and (file-readable-p (buffer-file-name))
                     (not (verify-visited-file-modtime (current-buffer))))
@@ -306,23 +312,81 @@ Use `auto-revert-mode' to revert a particular buffer."
                            global-auto-revert-non-file-buffers)
                       auto-revert-mode))))))
 
+(defun auto-revert-vc-cvs-file-version (file)
+  "Get version of FILE by reading control file on disk."
+  (let* ((control "CVS/Entries")
+         (name    (file-name-nondirectory file))
+         (path    (format "%s/%s"
+                          (file-name-directory file)
+                          control)))
+    (when (file-exists-p path)
+      (with-temp-buffer
+        (insert-file-contents-literally path)
+        (goto-char (point-min))
+        (when (re-search-forward
+               ;; /file.txt/1.3/Mon Sep 15 18:43:20 2003//
+               (format "%s/\\([.0-9]+\\)" (regexp-quote name))
+               nil t)
+          (match-string 1))))))
+
+(defun auto-revert-vc-buffer-p ()
+  "Check if buffer is version controlled."
+  (and (boundp 'vc-mode)
+       (string-match "[0-9]" (or vc-mode ""))))
+
+(defun auto-revert-handler-vc ()
+  "Check if version controlled buffer needs revert."
+  ;; [Emacs 1]
+  ;; 1. File is saved     (*)
+  ;; 2. checkin is done 1.1 -> 1.2
+  ;; 3. VC reverts, so that updated version number is shown in mode line
+  ;;
+  ;; Suppose the same file has been opened in another Emacs and
+  ;; autorevert.el is on.
+  ;;
+  ;; [Emacs 2]
+  ;; 1. Step (1) is detected and buffer is reverted.
+  ;; 2. But check in does not always change the file in dis, but possibly only
+  ;;    control files like CVS/Entries
+  ;; 3. The buffer is not reverted to update VC version line.
+  ;;    Incorrect version number 1.1 is shown in this Emacs
+  ;;
+  (when (featurep 'vc)
+    (let* ((file           (buffer-file-name))
+           (backend        (vc-backend (buffer-file-name)))
+           (version-buffer (vc-workfile-version file)))
+      (when (stringp version-buffer)
+        (cond
+         ((eq backend 'CVS)
+          (let ((version-file
+                 (auto-revert-vc-cvs-file-version (buffer-file-name))))
+            (and (stringp version-file)
+                 (not (string-match version-file version-buffer)))))
+         ((eq backend 'RCS)
+          ;; TODO:
+          ))))))
+
 (defun auto-revert-handler ()
   "Revert current buffer."
-  (let (done)
+  (let (revert)
     (cond
      ((eq major-mode 'dired-mode)
       ;;  Dired includes revert-buffer-function
       (when (and revert-buffer-function
                  (auto-revert-dired-changed-p))
-        (setq done t)
-        (revert-buffer t t t)))
+        (setq revert t)))
+     ((auto-revert-vc-buffer-p)
+      (when (auto-revert-handler-vc)
+        (setq revert 'vc)))
      ((or (buffer-file-name)
           revert-buffer-function)
-      (setq done t)
-      (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)))
-    (if (and done
-             auto-revert-verbose)
-        (message "Reverting buffer `%s'." (buffer-name)))))
+      (setq revert t)))
+    (when revert
+      (revert-buffer 'ignore-auto 'dont-ask 'preserve-modes)
+      (if (eq revert 'vc)
+          (vc-mode-line buffer-file-name))
+      (if auto-revert-verbose
+          (message "Reverting buffer `%s'." (buffer-name))))))
 
 (defun auto-revert-buffers ()
   "Revert buffers as specified by Auto-Revert and Global Auto-Revert Mode.