* fileio.c: Improve handling of file time marker. (Bug#11852)

(special_mtime): New function.
(Finsert_file_contents, Fverify_visited_file_modtime):
Use it to set special mtime values consistently.

2 files changed, 31 insertions, 19 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index a82d2a03af8..87e92170261 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2012-07-03  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * fileio.c: Improve handling of file time marker.  (Bug#11852)
+        (special_mtime): New function.
+        (Finsert_file_contents, Fverify_visited_file_modtime):
+        Use it to set special mtime values consistently.
+
 2012-07-03  Andreas Schwab  <schwab@linux-m68k.org>
 
         * fileio.c (Finsert_file_contents): Properly handle st_mtime
diff --git a/src/fileio.c b/src/fileio.c
index 820dabff53e..6c3a3b206e8 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -3215,6 +3215,17 @@ emacs_lseek (int fd, EMACS_INT offset, int whence)
   return lseek (fd, offset, whence);
 }
 
+/* Return a special mtime value indicating the error number ERRNUM.  */
+static EMACS_TIME
+special_mtime (int errnum)
+{
+  EMACS_TIME t;
+  int ns = (errno == ENOENT || errno == EACCES || errno == ENOTDIR
+            ? NONEXISTENT_MODTIME_NSECS
+            : UNKNOWN_MODTIME_NSECS);
+  EMACS_SET_SECS_NSECS (t, 0, ns);
+  return t;
+}
 
 DEFUN ("insert-file-contents", Finsert_file_contents, Sinsert_file_contents,
        1, 5, 0,
@@ -3242,6 +3253,8 @@ variable `last-coding-system-used' to the coding system actually used.  */)
   (Lisp_Object filename, Lisp_Object visit, Lisp_Object beg, Lisp_Object end, Lisp_Object replace)
 {
   struct stat st;
+  int file_status;
+  EMACS_TIME mtime;
   register int fd;
   ptrdiff_t inserted = 0;
   int nochange = 0;
@@ -3310,19 +3323,22 @@ variable `last-coding-system-used' to the coding system actually used.  */)
 
     /* Tell stat to use expensive method to get accurate info.  */
     Vw32_get_true_file_attributes = Qt;
-    total = stat (SSDATA (filename), &st);
+    file_status = stat (SSDATA (filename), &st);
     Vw32_get_true_file_attributes = tem;
   }
-  if (total < 0)
 #else
-  if (stat (SSDATA (filename), &st) < 0)
+  file_status = stat (SSDATA (filename), &st);
 #endif /* WINDOWSNT */
+
+  if (file_status == 0)
+    mtime = get_stat_mtime (&st);
+  else
     {
     badopen:
       save_errno = errno;
       if (NILP (visit))
         report_file_error ("Opening input file", Fcons (orig_filename, Qnil));
-      st.st_mtime = -1;
+      mtime = special_mtime (save_errno);
       st.st_size = -1;
       how_much = 0;
       if (!NILP (Vcoding_system_for_read))
@@ -4193,10 +4209,7 @@ variable `last-coding-system-used' to the coding system actually used.  */)
 
       if (NILP (handler))
         {
-          if (st.st_mtime == -1)
-            EMACS_SET_INVALID_TIME (current_buffer->modtime);
-          else
-            current_buffer->modtime = get_stat_mtime (&st);
+          current_buffer->modtime = mtime;
           current_buffer->modtime_size = st.st_size;
           BVAR (current_buffer, filename) = orig_filename;
         }
@@ -5093,17 +5106,9 @@ See Info node `(elisp)Modification Time' for more details.  */)
 
   filename = ENCODE_FILE (BVAR (b, filename));
 
-  if (stat (SSDATA (filename), &st) == 0)
-    mtime = get_stat_mtime (&st);
-  else
-    {
-      /* If the file doesn't exist now and didn't exist before,
-         we say that it isn't modified, provided the error is a tame one.  */
-      int ns = (errno == ENOENT || errno == EACCES || errno == ENOTDIR
-                ? NONEXISTENT_MODTIME_NSECS
-                : UNKNOWN_MODTIME_NSECS);
-      EMACS_SET_SECS_NSECS (mtime, 0, ns);
-    }
+  mtime = (stat (SSDATA (filename), &st) == 0
+           ? get_stat_mtime (&st)
+           : special_mtime (errno));
   if ((EMACS_TIME_EQ (mtime, b->modtime)
        /* If both exist, accept them if they are off by one second.  */
        || (EMACS_TIME_VALID_P (mtime) && EMACS_TIME_VALID_P (b->modtime)