Revert "Replace custom nixfmt wrapping with reformatter"

This reverts commit fb6c1ca.

Author: matthewbauer

flake.nix

@@ -16,7 +16,6 @@
           f
           magit-section
           transient
-          reformatter
         ]);
       in stdenvNoCC.mkDerivation {
         pname = "nix-mode";

nix-format.el

@@ -7,23 +7,48 @@
 ;;; Commentary:
 
 ;;; Code:
-(require 'reformatter)
 
 (defcustom nix-nixfmt-bin "nixfmt"
   "Path to nixfmt executable."
   :group 'nix
   :type 'string)
 
-;;;###autoload (autoload 'nixfmt-buffer "nix-format")
-;;;###autoload (autoload 'nixfmt-region "nix-format")
-;;;###autoload (autoload 'nixfmt-on-save-mode "nix-format")
-(reformatter-define nixfmt
-  :program nix-nixfmt-bin
-  :args (list input-file)
-  :stdin nil
-  :stdout nil
-  :input-file (reformatter-temp-file-in-current-directory)
-  :group 'nix)
+(if (fboundp 'replace-buffer-contents)
+    (defun nix--replace-buffer-contents (src dst)
+      (with-current-buffer dst (replace-buffer-contents src)))
+  (defun nix--replace-buffer-contents (src dst)
+    (if (not (string= (with-current-buffer src (buffer-string))
+		      (with-current-buffer dst (buffer-string))))
+	(with-current-buffer src
+	  (copy-to-buffer dst (point-min) (point-max))))))
+
+(defun nix--format-call (buf nixfmt-bin)
+  "Format BUF using nixfmt."
+  (with-current-buffer (get-buffer-create "*nixfmt*")
+    (erase-buffer)
+    (insert-buffer-substring buf)
+    (if (zerop (call-process-region (point-min) (point-max) nixfmt-bin t t nil))
+	(nix--replace-buffer-contents (current-buffer) buf)
+      (error "Nixfmt failed, see *nixfmt* buffer for details"))))
+
+(defun nix--find-nixfmt ()
+  "Find the nixfmt binary, or error if it's missing."
+  (let ((nixfmt-bin (executable-find nix-nixfmt-bin)))
+    (unless nixfmt-bin
+      (error "Could not locate executable %S" nix-nixfmt-bin))
+    nixfmt-bin))
+
+(defun nix-format-buffer ()
+  "Format the current buffer using nixfmt."
+  (interactive)
+  (nix--format-call (current-buffer) (nix--find-nixfmt))
+  (message "Formatted buffer with nixfmt."))
+
+;;;###autoload
+(defun nix-format-before-save ()
+  "Add this to `before-save-hook' to run nixfmt when saving."
+  (when (derived-mode-p 'nix-mode)
+    (nix-format-buffer)))
 
 (provide 'nix-format)
 ;;; nix-format.el ends here

nix-mode.el

@@ -4,7 +4,7 @@
 ;; Homepage: https://github.com/NixOS/nix-mode
 ;; Version: 1.5.0
 ;; Keywords: nix, languages, tools, unix
-;; Package-Requires: ((emacs "25.1") magit-section (transient "0.3") (reformatter "0.6"))
+;; Package-Requires: ((emacs "25.1") magit-section (transient "0.3"))
 
 ;; This file is NOT part of GNU Emacs.