File-name completion of non-ASCII characters on OS X (bug#22169)

The coding system `utf-8-nfd', locally defined in ns-win.el,
didn't provide a :pre-write-conversion method, causing file name
completion of non-ASCII characters to fail.  Solved by using the
`utf-8-hfs' coding system provided by `ucs-normalize'.

* lisp/loadup.el: Load international/ucs-normalize (when building
for ns).

* lisp/term/ns-win.el (utf-8-nfd): Made `utf-8-nfd' as alias for
`utf-8-hfs' and removed the old implementation.  Set `utf-8-hfs'
as the file name coding system.

* src/nsfns.c (ns-convert-utf8-nfd-to-nfc): Removed.

3 files changed, 7 insertions, 56 deletions

diff --git a/lisp/loadup.el b/lisp/loadup.el
index f0caa8be349..dda433e4eaf 100644
--- a/lisp/loadup.el
+++ b/lisp/loadup.el
@@ -276,6 +276,7 @@
 (if (featurep 'ns)
     (progn
       (load "term/common-win")
+      (load "international/ucs-normalize")
       (load "term/ns-win")))
 (if (fboundp 'x-create-frame)
     ;; Do it after loading term/foo-win.el since the value of the
diff --git a/lisp/term/ns-win.el b/lisp/term/ns-win.el
index 0b3e3bd9d9c..9bd59fc1954 100644
--- a/lisp/term/ns-win.el
+++ b/lisp/term/ns-win.el
@@ -51,6 +51,7 @@
 (require 'menu-bar)
 (require 'fontset)
 (require 'dnd)
+(require 'ucs-normalize)
 
 (defgroup ns nil
   "GNUstep/Mac OS X specific features."
@@ -337,29 +338,12 @@ See `ns-insert-working-text'."
   (setq ns-working-overlay nil))
 
 
-(declare-function ns-convert-utf8-nfd-to-nfc "nsfns.m" (str))
-
-;;;; OS X file system Unicode UTF-8 NFD (decomposed form) support
-;; Lisp code based on utf-8m.el, by Seiji Zenitani, Eiji Honjoh, and
-;; Carsten Bormann.
+;; OS X file system Unicode UTF-8 NFD (decomposed form) support.
 (when (eq system-type 'darwin)
-  (defun ns-utf8-nfd-post-read-conversion (length)
-    "Calls `ns-convert-utf8-nfd-to-nfc' to compose char sequences."
-    (save-excursion
-      (save-restriction
-        (narrow-to-region (point) (+ (point) length))
-        (let ((str (buffer-string)))
-          (delete-region (point-min) (point-max))
-          (insert (ns-convert-utf8-nfd-to-nfc str))
-          (- (point-max) (point-min))))))
-
-  (define-coding-system 'utf-8-nfd
-    "UTF-8 NFD (decomposed) encoding."
-    :coding-type 'utf-8
-    :mnemonic ?U
-    :charset-list '(unicode)
-    :post-read-conversion 'ns-utf8-nfd-post-read-conversion)
-  (set-file-name-coding-system 'utf-8-nfd))
+  ;; Used prior to Emacs 25.
+  (define-coding-system-alias 'utf-8-nfd 'utf-8-hfs)
+
+  (set-file-name-coding-system 'utf-8-hfs))
 
 ;;;; Inter-app communications support.
 
diff --git a/src/nsfns.m b/src/nsfns.m
index edc02e8350b..5fa68c0a15c 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -2099,39 +2099,6 @@ there was no result.  */)
 }
 
 
-DEFUN ("ns-convert-utf8-nfd-to-nfc", Fns_convert_utf8_nfd_to_nfc,
-       Sns_convert_utf8_nfd_to_nfc, 1, 1, 0,
-       doc: /* Return an NFC string that matches the UTF-8 NFD string STR.  */)
-     (Lisp_Object str)
-{
-/* TODO: If GNUstep ever implements precomposedStringWithCanonicalMapping,
-         remove this. */
-  NSString *utfStr;
-  Lisp_Object ret = Qnil;
-  NSAutoreleasePool *pool;
-
-  CHECK_STRING (str);
-  pool = [[NSAutoreleasePool alloc] init];
-  utfStr = [NSString stringWithUTF8String: SSDATA (str)];
-#ifdef NS_IMPL_COCOA
-  if (utfStr)
-    utfStr = [utfStr precomposedStringWithCanonicalMapping];
-#endif
-  if (utfStr)
-    {
-      const char *cstr = [utfStr UTF8String];
-      if (cstr)
-        ret = build_string (cstr);
-    }
-
-  [pool release];
-  if (NILP (ret))
-    error ("Invalid UTF-8");
-
-  return ret;
-}
-
-
 #ifdef NS_IMPL_COCOA
 
 /* Compile and execute the AppleScript SCRIPT and return the error
@@ -3207,7 +3174,6 @@ be used as the image of the icon representing the frame.  */);
   defsubr (&Sns_emacs_info_panel);
   defsubr (&Sns_list_services);
   defsubr (&Sns_perform_service);
-  defsubr (&Sns_convert_utf8_nfd_to_nfc);
   defsubr (&Sns_popup_font_panel);
   defsubr (&Sns_popup_color_panel);