(set-buffer-file-coding-system): New arg NOMODIFY.

(after-insert-file-set-coding): Pass that new arg.
Prevent set-buffer-multibyte from trying to lock the file.

1 files changed, 12 insertions, 5 deletions

diff --git a/lisp/international/mule.el b/lisp/international/mule.el
index 9136a257ee1..5477402a9ba 100644
--- a/lisp/international/mule.el
+++ b/lisp/international/mule.el
@@ -1135,7 +1135,7 @@ FROM is a form to evaluate to define the coding-system."
   (setq coding-system-alist (cons (list (symbol-name symbol))
                                   coding-system-alist)))
 
-(defun set-buffer-file-coding-system (coding-system &optional force)
+(defun set-buffer-file-coding-system (coding-system &optional force nomodify)
   "Set the file coding-system of the current buffer to CODING-SYSTEM.
 This means that when you save the buffer, it will be converted
 according to CODING-SYSTEM.  For a list of possible values of CODING-SYSTEM,
@@ -1149,8 +1149,9 @@ specified there).  Otherwise, leave it unspecified.
 
 This marks the buffer modified so that the succeeding \\[save-buffer]
 surely saves the buffer with CODING-SYSTEM.  From a program, if you
-don't want to mark the buffer modified, just set the variable
-`buffer-file-coding-system' directly."
+don't want to mark the buffer modified, specify t for NOMODIFY.
+If you know exactly what coding system you want to use,
+just set the variable `buffer-file-coding-system' directly."
   (interactive "zCoding system for saving file (default, nil): \nP")
   (check-coding-system coding-system)
   (if (and coding-system buffer-file-coding-system (null force))
@@ -1736,7 +1737,11 @@ different if the buffer has become unibyte."
              (find-new-buffer-file-coding-system last-coding-system-used))
             (modified-p (buffer-modified-p)))
         (when coding-system
-          (set-buffer-file-coding-system coding-system t)
+          ;; Tell set-buffer-file-coding-system not to mark the file
+          ;; as modified; we just read it, and it's supposed to be unmodified.
+          ;; Marking it modified would try to lock it, which would
+          ;; check the modtime, and we don't want to do that again now.
+          (set-buffer-file-coding-system coding-system t t)
           (if (and enable-multibyte-characters
                    (or (eq coding-system 'no-conversion)
                        (eq (coding-system-type coding-system) 5))
@@ -1746,7 +1751,9 @@ different if the buffer has become unibyte."
                    (= (buffer-size) inserted))
               ;; For coding systems no-conversion and raw-text...,
               ;; edit the buffer as unibyte.
-              (let ((pos-marker (copy-marker (+ (point) inserted))))
+              (let ((pos-marker (copy-marker (+ (point) inserted)))
+                    ;; Prevent locking.
+                    (buffer-file-name nil))
                 (set-buffer-multibyte nil)
                 (setq inserted (- pos-marker (point)))))
           (set-buffer-modified-p modified-p))))