Merge pull request #183 from terlar/master

Use ws-butler when enabled and available.

editorconfig.el

@@ -277,6 +277,14 @@ properties."
   :type '(repeat string)
   :group 'editorconfig)
 
+(defcustom editorconfig-trim-whitespaces-mode nil
+  "Buffer local minor-mode to use to trim trailing whitespaces.
+
+If set, enable that mode when `trim_trailing_whitespace` is set to true.
+Otherwise, use `delete-trailing-whitespace'."
+  :type 'symbol
+  :group 'editorconfig)
+
 (defvar editorconfig-properties-hash nil
   "Hash object of EditorConfig properties for current buffer.
 Set by `editorconfig-apply' and nil if that is not invoked in
@@ -417,20 +425,23 @@ number - `lisp-indent-offset' is not set only if indent_size is
     (set      (make-local-variable 'mode-require-final-newline) nil))))
 
 (defun editorconfig-set-trailing-ws (trim-trailing-ws)
-  "Set up trimming of trailing whitespace at end of lines by
-TRIM-TRAILING-WS."
+  "Set up trimming of trailing whitespace at end of lines by TRIM-TRAILING-WS."
   (make-local-variable 'write-file-functions) ;; just current buffer
   (when (and (equal trim-trailing-ws "true")
              (not buffer-read-only))
     ;; when true we push delete-trailing-whitespace (emacs > 21)
     ;; to write-file-functions
-    (add-to-list
-     'write-file-functions
-     'delete-trailing-whitespace))
+    (if editorconfig-trim-whitespaces-mode
+        (funcall editorconfig-trim-whitespaces-mode 1)
+      (add-to-list
+       'write-file-functions
+       'delete-trailing-whitespace)))
   (when (or (equal trim-trailing-ws "false")
             buffer-read-only)
     ;; when false we remove every delete-trailing-whitespace
     ;; from write-file-functions
+    (when editorconfig-trim-whitespaces-mode
+      (funcall editorconfig-trim-whitespaces-mode 0))
     (setq
      write-file-functions
      (delete