2 files changed, 77 insertions, 20 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 502cc2ff8c0..7eef2c80382 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,18 @@
+2013-01-11  Michael Albinus  <michael.albinus@gmx.de>
+
+        * autorevert.el (top): Require 'cl in order to pacify byte compiler.
+        (auto-revert-notify-rm-watch): Ignore errors.
+        (auto-revert-notify-add-watch): Ignore errors.  Use '(modify) for
+        inotify, and '(size last-write-time) for w32notify.  Set
+        buffer-local `auto-revert-use-notify' to nil when adding a file
+        watch fails - this is a fallback to the file modification check.
+        (auto-revert-notify-event-p, auto-revert-notify-event-descriptor)
+        (auto-revert-notify-event-action)
+        (auto-revert-notify-event-file-name): New defuns.
+        (auto-revert-notify-handler): Use them.  Implement first
+        plausibility checks.
+        (auto-revert-handler): Handle also `auto-revert-tail-mode'.
+
 2013-01-11  Julien Danjou  <julien@danjou.info>
 
         * color.el (color-rgb-to-hsv): Fix conversion computing in case min and
diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index ea7e6ca3a36..78c4aaaa143 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -97,6 +97,7 @@
 
 ;; Dependencies:
 
+(eval-when-compile (require 'cl))
 (require 'timer)
 
 ;; Custom Group:
@@ -466,9 +467,10 @@ will use an up-to-date value of `auto-revert-interval'"
 (defun auto-revert-notify-rm-watch ()
   "Disable file watch for current buffer's associated file."
   (when auto-revert-notify-watch-descriptor
-    (funcall (if (fboundp 'inotify-rm-watch)
-                 'inotify-rm-watch 'w32notify-rm-watch)
-             auto-revert-notify-watch-descriptor)
+    (ignore-errors
+      (funcall (if (fboundp 'inotify-rm-watch)
+                   'inotify-rm-watch 'w32notify-rm-watch)
+               auto-revert-notify-watch-descriptor))
     (remhash auto-revert-notify-watch-descriptor
              auto-revert-notify-watch-descriptor-hash-list))
   (setq auto-revert-notify-watch-descriptor nil
@@ -481,21 +483,62 @@ will use an up-to-date value of `auto-revert-interval'"
     (let ((func (if (fboundp 'inotify-add-watch)
                     'inotify-add-watch 'w32notify-add-watch))
           (aspect (if (fboundp 'inotify-add-watch)
-                      '(close-write) '(last-write-time))))
+                      '(modify) '(size last-write-time))))
       (setq auto-revert-notify-watch-descriptor
-            (funcall func buffer-file-name aspect 'auto-revert-notify-handler))
-      (puthash auto-revert-notify-watch-descriptor
-               (current-buffer)
-               auto-revert-notify-watch-descriptor-hash-list))))
+            (ignore-errors
+              (funcall
+               func buffer-file-name aspect 'auto-revert-notify-handler)))
+      (if auto-revert-notify-watch-descriptor
+          (puthash auto-revert-notify-watch-descriptor
+                   (current-buffer)
+                   auto-revert-notify-watch-descriptor-hash-list)
+        ;; Fallback to file checks.
+        (set (make-local-variable 'auto-revert-use-notify) nil)))))
+
+(defun auto-revert-notify-event-p (event)
+  "Check that event is a file watch event."
+  (cond ((featurep 'inotify)
+         (and (listp event) (= (length event) 4)))
+        ((featurep 'w32notify)
+         (and (listp event) (= (length event) 3) (stringp (nth 2 event))))))
+
+(defun auto-revert-notify-event-descriptor (event)
+  "Return watch descriptor of notification event, or nil."
+  (and (auto-revert-notify-event-p event) (car event)))
+
+(defun auto-revert-notify-event-action (event)
+  "Return action of notification event, or nil."
+  (and (auto-revert-notify-event-p event) (nth 1 event)))
+
+(defun auto-revert-notify-event-file-name (event)
+  "Return file name of notification event, or nil."
+  (and (auto-revert-notify-event-p event)
+       (cond ((featurep 'inotify) (nth 3 event))
+             ((featurep 'w32notify) (nth 2 event)))))
 
 (defun auto-revert-notify-handler (event)
   "Handle an event returned from file watch."
-  (when (listp event)
-    (let ((buffer
-           (gethash (car event) auto-revert-notify-watch-descriptor-hash-list)))
-      (when (bufferp buffer)
-        (with-current-buffer buffer
-          (setq auto-revert-notify-modified-p t))))))
+  (when (auto-revert-notify-event-p event)
+    (let* ((descriptor (auto-revert-notify-event-descriptor event))
+           (action (auto-revert-notify-event-action event))
+           (file (auto-revert-notify-event-file-name event))
+           (buffer (gethash descriptor
+                            auto-revert-notify-watch-descriptor-hash-list)))
+      ;; Check, that event is meant for us.
+      ;; TODO: Filter events which stop watching, like `move' or `removed'.
+      (ignore-errors
+        (assert descriptor)
+        (when (featurep 'inotify) (assert (memq 'modify descriptor)))
+        (when (featurep 'w32notify) (assert (eq 'modified descriptor)))
+        (assert (bufferp buffer))
+        (when (stringp file)
+          (assert (string-equal
+                   (directory-file-name file)
+                   (directory-file-name (buffer-file-name buffer))))))
+
+      ;; Mark buffer modified.
+      (with-current-buffer buffer
+        (setq auto-revert-notify-modified-p t)))))
 
 (defun auto-revert-active-p ()
   "Check if auto-revert is active (in current buffer or globally)."
@@ -514,6 +557,8 @@ This is an internal function used by Auto-Revert Mode."
     (let* ((buffer (current-buffer)) size
            (revert
             (or (and buffer-file-name
+                     (or (not auto-revert-use-notify)
+                         auto-revert-notify-modified-p)
                      (if auto-revert-tail-mode
                          ;; Tramp caches the file attributes.  Setting
                          ;; `remote-file-name-inhibit-cache' forces Tramp
@@ -524,12 +569,9 @@ This is an internal function used by Auto-Revert Mode."
                                     (setq size
                                           (nth 7 (file-attributes
                                                   buffer-file-name))))))
-                       (if auto-revert-use-notify
-                           ;; There are file watches.
-                           auto-revert-notify-modified-p
-                         (and (not (file-remote-p buffer-file-name))
-                              (file-readable-p buffer-file-name)
-                              (not (verify-visited-file-modtime buffer))))))
+                       (and (not (file-remote-p buffer-file-name))
+                            (file-readable-p buffer-file-name)
+                            (not (verify-visited-file-modtime buffer)))))
                 (and (or auto-revert-mode
                          global-auto-revert-non-file-buffers)
                      revert-buffer-function