* progmodes/compile.el (compilation-mode-hook)

[bpt/emacs.git] / src / fileio.c

diff --git a/src/fileio.c b/src/fileio.c
index ac0ce20..fb6ecfe 100644 (file)
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -82,6 +82,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #endif
 
 #include "systime.h"
+#include <allocator.h>
+#include <careadlinkat.h>
 #include <stat-time.h>
 
 #ifdef HPUX
@@ -2759,6 +2761,29 @@ If there is no error, returns nil.  */)
   return Qnil;
 }
 \f
+/* Relative to directory FD, return the symbolic link value of FILENAME.
+   On failure, return nil.  */
+Lisp_Object
+emacs_readlinkat (int fd, char const *filename)
+{
+  static struct allocator const emacs_norealloc_allocator =
+    { xmalloc, NULL, xfree, memory_full };
+  Lisp_Object val;
+  char readlink_buf[1024];
+  char *buf = careadlinkat (fd, filename, readlink_buf, sizeof readlink_buf,
+                           &emacs_norealloc_allocator, readlinkat);
+  if (!buf)
+    return Qnil;
+
+  val = build_string (buf);
+  if (buf[0] == '/' && strchr (buf, ':'))
+    val = concat2 (build_string ("/:"), val);
+  if (buf != readlink_buf)
+    xfree (buf);
+  val = DECODE_FILE (val);
+  return val;
+}
+
 DEFUN ("file-symlink-p", Ffile_symlink_p, Sfile_symlink_p, 1, 1, 0,
        doc: /* Return non-nil if file FILENAME is the name of a symbolic link.
 The value is the link target, as a string.
@@ -2769,9 +2794,6 @@ points to a nonexistent file.  */)
   (Lisp_Object filename)
 {
   Lisp_Object handler;
-  char *buf;
-  Lisp_Object val;
-  char readlink_buf[READLINK_BUFSIZE];
 
   CHECK_STRING (filename);
   filename = Fexpand_file_name (filename, Qnil);
@@ -2784,17 +2806,7 @@ points to a nonexistent file.  */)
 
   filename = ENCODE_FILE (filename);
 
-  buf = emacs_readlink (SSDATA (filename), readlink_buf);
-  if (! buf)
-    return Qnil;
-
-  val = build_string (buf);
-  if (buf[0] == '/' && strchr (buf, ':'))
-    val = concat2 (build_string ("/:"), val);
-  if (buf != readlink_buf)
-    xfree (buf);
-  val = DECODE_FILE (val);
-  return val;
+  return emacs_readlinkat (AT_FDCWD, SSDATA (filename));
 }
 
 DEFUN ("file-directory-p", Ffile_directory_p, Sfile_directory_p, 1, 1, 0,
@@ -4881,10 +4893,9 @@ This calls `write-region-annotate-functions' at the start, and
      We used to make this choice before calling build_annotations, but that
      leads to problems when a write-annotate-function takes care of
      unsavable chars (as was the case with X-Symbol).  */
-  Vlast_coding_system_used = NILP (Vcoding_system_for_write) ?
+  Vlast_coding_system_used =
     Fchoose_write_coding_system (start, end, filename,
-                                append, visit, lockname) :
-    Vcoding_system_for_write;
+                                 append, visit, lockname);
 
   setup_coding_system (Vlast_coding_system_used, &coding);
 
@@ -5025,7 +5036,11 @@ This calls `write-region-annotate-functions' at the start, and
              && st.st_dev == st1.st_dev && st.st_ino == st1.st_ino)
            {
              EMACS_TIME modtime1 = get_stat_mtime (&st1);
-             if (EMACS_TIME_EQ (modtime, modtime1)
+             /* If neither O_EXCL nor O_TRUNC is used, and Emacs happened to
+                write nothing to the file, the file's time stamp won't change
+                so it should not be used in this heuristic.  */
+             if ((open_flags & (O_EXCL | O_TRUNC)) != 0
+                 && EMACS_TIME_EQ (modtime, modtime1)
                  && st.st_size == st1.st_size)
                {
                  timestamp_file_system = st.st_dev;