file-attributes has a new optional arg FOLLOW-SYMLINKS.

* doc/lispref/files.texi (File Attributes): Describe it.
(Magic File Names): Use it.
* etc/NEWS: Document the change.
* lisp/files.el (remote-file-name-inhibit-cache):
* lisp/time.el (display-time-file-nonempty-p): Use it.
* lisp/files.el (after-find-file): Don't chase links before calling
file-exists-p, as file-exists-p already does the right thing.
* src/dired.c (directory_files_internal, Ffile_attributes):
New arg follow_symlinks.  All uses changed.

4 files changed, 27 insertions, 10 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 1d3d1f7f4e2..257333a3f98 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-30  Paul Eggert  <eggert@cs.ucla.edu>
+
+        file-attributes has a new optional arg FOLLOW-SYMLINKS.
+        * dired.c (directory_files_internal, Ffile_attributes):
+        New arg follow_symlinks.  All uses changed.
+
 2012-09-30  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * .gdbinit (xbacktrace): Adjust to recent "struct backtrace" change.
diff --git a/src/dired.c b/src/dired.c
index 4986f845101..84a172deb58 100644
--- a/src/dired.c
+++ b/src/dired.c
@@ -110,12 +110,13 @@ directory_files_internal_unwind (Lisp_Object dh)
 /* Function shared by Fdirectory_files and Fdirectory_files_and_attributes.
    If not ATTRS, return a list of directory filenames;
    if ATTRS, return a list of directory filenames and their attributes.
-   In the latter case, ID_FORMAT is passed to Ffile_attributes.  */
+   In the latter case, ID_FORMAT and FOLLOW_SYMLINKS are passed to
+   Ffile_attributes.  */
 
 Lisp_Object
 directory_files_internal (Lisp_Object directory, Lisp_Object full,
                           Lisp_Object match, Lisp_Object nosort, bool attrs,
-                          Lisp_Object id_format)
+                          Lisp_Object id_format, Lisp_Object follow_symlinks)
 {
   DIR *d;
   ptrdiff_t directory_nbytes;
@@ -297,7 +298,8 @@ directory_files_internal (Lisp_Object directory, Lisp_Object full,
 
                   /* Both Fexpand_file_name and Ffile_attributes can GC.  */
                   decoded_fullname = Fexpand_file_name (name, directory);
-                  fileattrs = Ffile_attributes (decoded_fullname, id_format);
+                  fileattrs = Ffile_attributes (decoded_fullname, id_format,
+                                                follow_symlinks);
 
                   list = Fcons (Fcons (finalname, fileattrs), list);
                   UNGCPRO;
@@ -350,7 +352,8 @@ If NOSORT is non-nil, the list is not sorted--its order is unpredictable.
     return call5 (handler, Qdirectory_files, directory,
                   full, match, nosort);
 
-  return directory_files_internal (directory, full, match, nosort, 0, Qnil);
+  return directory_files_internal (directory, full, match, nosort, 0,
+                                   Qnil, Qnil);
 }
 
 DEFUN ("directory-files-and-attributes", Fdirectory_files_and_attributes,
@@ -378,7 +381,8 @@ which see.  */)
     return call6 (handler, Qdirectory_files_and_attributes,
                   directory, full, match, nosort, id_format);
 
-  return directory_files_internal (directory, full, match, nosort, 1, id_format);
+  return directory_files_internal (directory, full, match, nosort, 1,
+                                   id_format, Qnil);
 }
 
 
@@ -875,7 +879,7 @@ stat_gname (struct stat *st)
 #endif
 }
 
-DEFUN ("file-attributes", Ffile_attributes, Sfile_attributes, 1, 2, 0,
+DEFUN ("file-attributes", Ffile_attributes, Sfile_attributes, 1, 3, 0,
        doc: /* Return a list of attributes of file FILENAME.
 Value is nil if specified file cannot be opened.
 
@@ -884,6 +888,9 @@ below) - valid values are 'string and 'integer.  The latter is the
 default, but we plan to change that, so you should specify a non-nil value
 for ID-FORMAT if you use the returned uid or gid.
 
+Optional argument FOLLOW-SYMLINKS says whether to follow symbolic
+links.  If t, they are followed; if nil, they are not.
+
 Elements of the attribute list are:
  0. t for directory, string (name linked to) for symbolic link, or nil.
  1. Number of links to file.
@@ -917,7 +924,7 @@ which see.
 
 On some FAT-based filesystems, only the date of last access is recorded,
 so last access time will always be midnight of that day.  */)
-  (Lisp_Object filename, Lisp_Object id_format)
+  (Lisp_Object filename, Lisp_Object id_format, Lisp_Object follow_symlinks)
 {
   Lisp_Object values[12];
   Lisp_Object encoded;
@@ -953,7 +960,10 @@ so last access time will always be midnight of that day.  */)
   encoded = ENCODE_FILE (filename);
   UNGCPRO;
 
-  if (lstat (SSDATA (encoded), &s) < 0)
+  if ((!NILP (follow_symlinks)
+       ? stat (SSDATA (encoded), &s)
+       : lstat (SSDATA (encoded), &s))
+      != 0)
     return Qnil;
 
   values[0] = (S_ISLNK (s.st_mode) ? Ffile_symlink_p (filename)
diff --git a/src/lisp.h b/src/lisp.h
index c3cabe0af29..e182d3bc14b 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3474,7 +3474,7 @@ extern void syms_of_ccl (void);
 extern void syms_of_dired (void);
 extern Lisp_Object directory_files_internal (Lisp_Object, Lisp_Object,
                                              Lisp_Object, Lisp_Object,
-                                             bool, Lisp_Object);
+                                             bool, Lisp_Object, Lisp_Object);
 
 /* Defined in term.c.  */
 extern int *char_ins_del_vector;
diff --git a/src/sysdep.c b/src/sysdep.c
index b7141011d05..b7ddafdcea7 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -2529,7 +2529,8 @@ list_system_processes (void)
      process.  */
   procdir = build_string ("/proc");
   match = build_string ("[0-9]+");
-  proclist = directory_files_internal (procdir, Qnil, match, Qt, 0, Qnil);
+  proclist = directory_files_internal (procdir, Qnil, match, Qt, 0,
+                                       Qnil, Qnil);
 
   /* `proclist' gives process IDs as strings.  Destructively convert
      each string into a number.  */