* eshell/em-ls.el (eshell-ls-applicable): Frob file attributes correctly (Bug#5548).

2 files changed, 27 insertions, 12 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 6d4c7062745..2ef03c3fb30 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2010-02-09  Chong Yidong  <cyd@stupidchicken.com>
+
+        * eshell/em-ls.el (eshell-ls-applicable): Frob file attributes
+        correctly (Bug#5548).
+
 2010-02-08  Jose E. Marchesi  <jemarch@gnu.org>
 
         * progmodes/ada-mode.el (ada-in-numeric-literal-p): New function.
diff --git a/lisp/eshell/em-ls.el b/lisp/eshell/em-ls.el
index 9b008cebf1a..860ad5c77d8 100644
--- a/lisp/eshell/em-ls.el
+++ b/lisp/eshell/em-ls.el
@@ -225,18 +225,28 @@ really need to stick around for very long."
       (eq (aref (nth 8 attrs) 0) type)))
 
 (defmacro eshell-ls-applicable (attrs index func file)
-  "Test whether, for ATTRS, the user UID can do what corresponds to INDEX.
-This is really just for efficiency, to avoid having to stat the file
-yet again."
-  `(if (numberp (nth 2 ,attrs))
-       (if (= (user-uid) (nth 2 ,attrs))
-           (not (eq (aref (nth 8 ,attrs) ,index) ?-))
-         (,(eval func) ,file))
-     (not (eq (aref (nth 8 ,attrs)
-                    (+ ,index (if (member (nth 2 ,attrs)
-                                          (eshell-current-ange-uids))
-                                  0 6)))
-              ?-))))
+  "Test whether, for ATTRS, the user can do what corresponds to INDEX.
+ATTRS is a string of file modes.  See `file-attributes'.
+If we cannot determine the answer using ATTRS (e.g., if we need
+to know what group the user is in), compute the return value by
+calling FUNC with FILE as an argument."
+  `(let ((owner (nth 2 ,attrs))
+         (modes (nth 8 ,attrs)))
+     (cond ((cond ((numberp owner)
+                   (= owner (user-uid)))
+                  ((stringp owner)
+                   (or (string-equal owner (user-login-name))
+                       (member owner (eshell-current-ange-uids)))))
+            ;; The user owns this file.
+            (not (eq (aref modes ,index) ?-)))
+           ((eq (aref modes (+ ,index 3))
+                (aref modes (+ ,index 6)))
+            ;; If the "group" and "other" fields give identical
+            ;; results, use that.
+            (not (eq (aref modes (+ ,index 3)) ?-)))
+           (t
+            ;; Otherwise call FUNC.
+            (,(eval func) ,file)))))
 
 (defcustom eshell-ls-highlight-alist nil
   "*This alist correlates test functions to color.