Support file notifications for dired auto-revert

* autorevert.el (auto-revert-notify-add-watch)
(auto-revert-notify-handler, auto-revert-buffers): Handle also
buffers without an associated file, like dired buffers.

2 files changed, 51 insertions, 39 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 7f5fb7ddf0d..0211458daab 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-21  Michael Albinus  <michael.albinus@gmx.de>
+
+        * autorevert.el (auto-revert-notify-add-watch)
+        (auto-revert-notify-handler, auto-revert-buffers): Handle also
+        buffers without an associated file, like dired buffers.
+
 2015-02-21  Dima Kogan  <dima@secretsauce.net>
 
         * autorevert.el (auto-revert-mode, auto-revert-tail-mode)
diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index 4dd021e4c76..6489a3e04c2 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -505,16 +505,22 @@ will use an up-to-date value of `auto-revert-interval'"
   ;; `auto-revert-use-notify' are non-nil.
   (when (or (string-match auto-revert-notify-exclude-dir-regexp
                           (expand-file-name default-directory))
-            (file-symlink-p buffer-file-name))
+            (file-symlink-p (or buffer-file-name default-directory)))
     ;; Fallback to file checks.
     (set (make-local-variable 'auto-revert-use-notify) nil))
 
   (when (not auto-revert-notify-watch-descriptor)
     (setq auto-revert-notify-watch-descriptor
           (ignore-errors
-            (file-notify-add-watch
-             (expand-file-name buffer-file-name default-directory)
-             '(change attribute-change) 'auto-revert-notify-handler)))
+            (if buffer-file-name
+                (file-notify-add-watch
+                 (expand-file-name buffer-file-name default-directory)
+                 '(change attribute-change)
+                 'auto-revert-notify-handler)
+              (file-notify-add-watch
+               (expand-file-name default-directory)
+               '(change)
+               'auto-revert-notify-handler))))
     (if auto-revert-notify-watch-descriptor
         (progn
           (puthash
@@ -563,40 +569,40 @@ no more reverts are possible until the next call of
                              auto-revert-notify-watch-descriptor-hash-list)))
       ;; Check, that event is meant for us.
       (cl-assert descriptor)
-      ;; We do not handle `deleted', because nothing has to be refreshed.
-      (unless (eq action 'deleted)
-        (cl-assert (memq action '(attribute-changed changed created renamed))
-                   t)
-        ;; Since we watch a directory, a file name must be returned.
-        (cl-assert (stringp file))
-        (when (eq action 'renamed) (cl-assert (stringp file1)))
-        ;; Loop over all buffers, in order to find the intended one.
-        (cl-dolist (buffer buffers)
-          (when (buffer-live-p buffer)
-            (with-current-buffer buffer
-              (when (and (stringp buffer-file-name)
-                         (or
-                          (and (memq action '(attribute-changed changed
-                                              created))
-                               (string-equal
-                                (file-name-nondirectory file)
-                                (file-name-nondirectory buffer-file-name)))
-                          (and (eq action 'renamed)
-                               (string-equal
-                                (file-name-nondirectory file1)
-                                (file-name-nondirectory buffer-file-name)))))
-                ;; Mark buffer modified.
-                (setq auto-revert-notify-modified-p t)
-
-                ;; Revert the buffer now if we're not locked out
-                (when (/= auto-revert-buffers-counter-lockedout
-                          auto-revert-buffers-counter)
-                  (auto-revert-handler)
-                  (setq auto-revert-buffers-counter-lockedout
-                        auto-revert-buffers-counter))
-
-                ;; No need to check other buffers.
-                (cl-return)))))))))
+      ;; Since we watch a directory, a file name must be returned.
+      (cl-assert (stringp file))
+      (when (eq action 'renamed) (cl-assert (stringp file1)))
+      ;; Loop over all buffers, in order to find the intended one.
+      (cl-dolist (buffer buffers)
+        (when (buffer-live-p buffer)
+          (with-current-buffer buffer
+            (when (or
+                   ;; A buffer associated with a file.
+                   (and (stringp buffer-file-name)
+                        (or
+                         (and (memq action '(attribute-changed changed created))
+                              (string-equal
+                               (file-name-nondirectory file)
+                               (file-name-nondirectory buffer-file-name)))
+                         (and (eq action 'renamed)
+                              (string-equal
+                               (file-name-nondirectory file1)
+                               (file-name-nondirectory buffer-file-name)))))
+                   ;; A buffer w/o a file, like dired.
+                   (and (null buffer-file-name)
+                        (memq action '(created renamed deleted))))
+              ;; Mark buffer modified.
+              (setq auto-revert-notify-modified-p t)
+
+              ;; Revert the buffer now if we're not locked out.
+              (when (/= auto-revert-buffers-counter-lockedout
+                        auto-revert-buffers-counter)
+                (auto-revert-handler)
+                (setq auto-revert-buffers-counter-lockedout
+                      auto-revert-buffers-counter))
+
+              ;; No need to check other buffers.
+              (cl-return))))))))
 
 (defun auto-revert-active-p ()
   "Check if auto-revert is active (in current buffer or globally)."
@@ -750,7 +756,7 @@ the timer when no buffers need to be checked."
                           (delq buf auto-revert-buffer-list)))
                 (when (auto-revert-active-p)
                   ;; Enable file notification.
-                  (when (and auto-revert-use-notify buffer-file-name
+                  (when (and auto-revert-use-notify
                              (not auto-revert-notify-watch-descriptor))
                     (auto-revert-notify-add-watch))
                   (auto-revert-handler)))