[Emacs-diffs] /srv/bzr/emacs/trunk r111638: Reduce delay between backing up a file and saving new version

[Glenn Morris]

------------------------------------------------------------
revno: 111638
fixes bug: http://debbugs.gnu.org/13522
committer: Glenn Morris <address@hidden>
branch nick: trunk
timestamp: Wed 2013-01-30 22:35:45 -0800
message:
  Reduce delay between backing up a file and saving new version
  
  * lisp/files.el (basic-save-buffer-2):
  Choose coding system for writing the file before backing it up.
  
  * src/fileio.c (choose_write_coding_system): Make it callable from Lisp.
  (Fwrite_region): If coding-system-for-write is set, don't call
  choose_write_coding_system.
  Move the last piece of choose_write_coding_system here.
  (syms_of_fileio): Add choose-write-coding-system.
modified:
  lisp/ChangeLog
  lisp/files.el
  src/ChangeLog
  src/fileio.c

=== modified file 'lisp/ChangeLog'
--- a/lisp/ChangeLog    2013-01-31 02:57:35 +0000
+++ b/lisp/ChangeLog    2013-01-31 06:35:45 +0000
@@ -1,3 +1,9 @@
+2013-01-31  Glenn Morris  <address@hidden>
+
+       * files.el (basic-save-buffer-2): Choose coding system for
+       writing the file before backing it up, to reduce delay between
+       backing up and writing the new version.  (Bug#13522)
+
 2013-01-31  Michal Nazarewicz  <address@hidden>
 
        * simple.el (cycle-spacing): New command.

=== modified file 'lisp/files.el'
--- a/lisp/files.el     2013-01-10 15:50:04 +0000
+++ b/lisp/files.el     2013-01-31 06:35:45 +0000
@@ -4656,7 +4656,7 @@
 ;; This returns a value (MODES EXTENDED-ATTRIBUTES BACKUPNAME), like
 ;; backup-buffer.
 (defun basic-save-buffer-2 ()
-  (let (tempsetmodes setmodes)
+  (let (tempsetmodes setmodes writecoding)
     (if (not (file-writable-p buffer-file-name))
        (let ((dir (file-name-directory buffer-file-name)))
          (if (not (file-directory-p dir))
@@ -4672,6 +4672,14 @@
                     buffer-file-name)))
                  (setq tempsetmodes t)
                (error "Attempt to save to a file which you aren't allowed to 
write"))))))
+    ;; This may involve prompting, so do it now before backing up the file.
+    ;; Otherwise there can be a delay while the user answers the
+    ;; prompt during which the original file has been renamed.  (Bug#13522)
+    (setq writecoding
+         ;; Args here should match write-region call below around
+         ;; which we use writecoding.
+         (choose-write-coding-system nil nil buffer-file-name nil t
+                                     buffer-file-truename))
     (or buffer-backed-up
        (setq setmodes (backup-buffer)))
     (let* ((dir (file-name-directory buffer-file-name))
@@ -4753,10 +4761,11 @@
                                 (logior (car setmodes) 128))))))
        (let (success)
          (unwind-protect
-             (progn
                 ;; Pass in nil&nil rather than point-min&max to indicate
                 ;; we're saving the buffer rather than just a region.
                 ;; write-region-annotate-functions may make us of it.
+             (let ((coding-system-for-write writecoding)
+                   (coding-system-require-warning nil))
                (write-region nil nil
                              buffer-file-name nil t buffer-file-truename)
                (setq success t))

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2013-01-30 08:07:37 +0000
+++ b/src/ChangeLog     2013-01-31 06:35:45 +0000
@@ -1,3 +1,11 @@
+2013-01-31  Glenn Morris  <address@hidden>
+
+       * fileio.c (choose_write_coding_system): Make it callable from Lisp.
+       (Fwrite_region): If coding-system-for-write is set, don't
+       call choose_write_coding_system.  Move the last piece of
+       choose_write_coding_system here.  (Bug#13522)
+       (syms_of_fileio): Add choose-write-coding-system.
+
 2013-01-30  Eli Zaretskii  <address@hidden>
 
        * w32.c (sys_open): Zero out the flags for the new file descriptor.

=== modified file 'src/fileio.c'
--- a/src/fileio.c      2013-01-23 20:07:28 +0000
+++ b/src/fileio.c      2013-01-31 06:35:45 +0000
@@ -249,6 +249,7 @@
 static Lisp_Object Qset_file_acl;
 static Lisp_Object Qfile_newer_than_file_p;
 Lisp_Object Qinsert_file_contents;
+Lisp_Object Qchoose_write_coding_system;
 Lisp_Object Qwrite_region;
 static Lisp_Object Qverify_visited_file_modtime;
 static Lisp_Object Qset_visited_file_modtime;
@@ -4615,14 +4616,24 @@
 
 /* Decide the coding-system to encode the data with.  */
 
-static Lisp_Object
-choose_write_coding_system (Lisp_Object start, Lisp_Object end, Lisp_Object 
filename,
-                           Lisp_Object append, Lisp_Object visit, Lisp_Object 
lockname,
-                           struct coding_system *coding)
+DEFUN ("choose-write-coding-system", Fchoose_write_coding_system,
+       Schoose_write_coding_system, 3, 6, 0,
+       doc: /* Choose the coding system for writing a file.
+Arguments are as for `write-region'.
+This function is for internal use only.  It may prompt the user.  */ )
+  (Lisp_Object start, Lisp_Object end, Lisp_Object filename,
+   Lisp_Object append, Lisp_Object visit, Lisp_Object lockname)
 {
   Lisp_Object val;
   Lisp_Object eol_parent = Qnil;
 
+  /* Mimic write-region behavior.  */
+  if (NILP (start))
+    {
+      XSETFASTINT (start, BEGV);
+      XSETFASTINT (end, ZV);
+    }
+
   if (auto_saving
       && NILP (Fstring_equal (BVAR (current_buffer, filename),
                              BVAR (current_buffer, auto_save_file_name))))
@@ -4715,10 +4726,6 @@
     }
 
   val = coding_inherit_eol_type (val, eol_parent);
-  setup_coding_system (val, coding);
-
-  if (!STRINGP (start) && !NILP (BVAR (current_buffer, selective_display)))
-    coding->mode |= CODING_MODE_SELECTIVE_DISPLAY;
   return val;
 }
 
@@ -4874,9 +4881,15 @@
      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
-    = choose_write_coding_system (start, end, filename,
-                                 append, visit, lockname, &coding);
+  Vlast_coding_system_used = NILP (Vcoding_system_for_write) ?
+    Fchoose_write_coding_system (start, end, filename,
+                                append, visit, lockname) :
+    Vcoding_system_for_write;
+
+  setup_coding_system (Vlast_coding_system_used, &coding);
+
+  if (!STRINGP (start) && !NILP (BVAR (current_buffer, selective_display)))
+    coding.mode |= CODING_MODE_SELECTIVE_DISPLAY;
 
 #ifdef CLASH_DETECTION
   if (!auto_saving)
@@ -5861,6 +5874,7 @@
   DEFSYM (Qset_file_acl, "set-file-acl");
   DEFSYM (Qfile_newer_than_file_p, "file-newer-than-file-p");
   DEFSYM (Qinsert_file_contents, "insert-file-contents");
+  DEFSYM (Qchoose_write_coding_system, "choose-write-coding-system");
   DEFSYM (Qwrite_region, "write-region");
   DEFSYM (Qverify_visited_file_modtime, "verify-visited-file-modtime");
   DEFSYM (Qset_visited_file_modtime, "set-visited-file-modtime");
@@ -6085,6 +6099,7 @@
   defsubr (&Sdefault_file_modes);
   defsubr (&Sfile_newer_than_file_p);
   defsubr (&Sinsert_file_contents);
+  defsubr (&Schoose_write_coding_system);
   defsubr (&Swrite_region);
   defsubr (&Scar_less_than_car);
   defsubr (&Sverify_visited_file_modtime);