1 ;;; clang-format.el --- Format code using clang-format -*- lexical-binding: t; -*- 2 3 ;; Keywords: tools, c 4 ;; Package-Requires: ((cl-lib "0.3")) 5 6 ;;; Commentary: 7 8 ;; This package allows to filter code through clang-format to fix its formatting. 9 ;; clang-format is a tool that formats C/C++/Obj-C code according to a set of 10 ;; style options, see <http://clang.llvm.org/docs/ClangFormatStyleOptions.html>. 11 ;; Note that clang-format 3.4 or newer is required. 12 13 ;; clang-format.el is available via MELPA and can be installed via 14 ;; 15 ;; M-x package-install clang-format 16 ;; 17 ;; when ("melpa" . "http://melpa.org/packages/") is included in 18 ;; `package-archives'. Alternatively, ensure the directory of this 19 ;; file is in your `load-path' and add 20 ;; 21 ;; (require 'clang-format) 22 ;; 23 ;; to your .emacs configuration. 24 25 ;; You may also want to bind `clang-format-region' to a key: 26 ;; 27 ;; (global-set-key [C-M-tab] 'clang-format-region) 28 29 ;;; Code: 30 31 (require 'cl-lib) 32 (require 'xml) 33 34 (defgroup clang-format nil 35 "Format code using clang-format." 36 :group 'tools) 37 38 (defcustom clang-format-executable 39 (or (executable-find "clang-format") 40 "clang-format") 41 "Location of the clang-format executable. 42 43 A string containing the name or the full path of the executable." 44 :group 'clang-format 45 :type '(file :must-match t) 46 :risky t) 47 48 (defcustom clang-format-style "file" 49 "Style argument to pass to clang-format. 50 51 By default clang-format will load the style configuration from 52 a file named .clang-format located in one of the parent directories 53 of the buffer." 54 :group 'clang-format 55 :type 'string 56 :safe #'stringp) 57 (make-variable-buffer-local 'clang-format-style) 58 59 (defun clang-format--extract (xml-node) 60 "Extract replacements and cursor information from XML-NODE." 61 (unless (and (listp xml-node) (eq (xml-node-name xml-node) 'replacements)) 62 (error "Expected <replacements> node")) 63 (let ((nodes (xml-node-children xml-node)) 64 (incomplete-format (xml-get-attribute xml-node 'incomplete_format)) 65 replacements 66 cursor) 67 (dolist (node nodes) 68 (when (listp node) 69 (let* ((children (xml-node-children node)) 70 (text (car children))) 71 (cl-case (xml-node-name node) 72 ('replacement 73 (let* ((offset (xml-get-attribute-or-nil node 'offset)) 74 (length (xml-get-attribute-or-nil node 'length))) 75 (when (or (null offset) (null length)) 76 (error "<replacement> node does not have offset and length attributes")) 77 (when (cdr children) 78 (error "More than one child node in <replacement> node")) 79 80 (setq offset (string-to-number offset)) 81 (setq length (string-to-number length)) 82 (push (list offset length text) replacements))) 83 ('cursor 84 (setq cursor (string-to-number text))))))) 85 86 ;; Sort by decreasing offset, length. 87 (setq replacements (sort (delq nil replacements) 88 (lambda (a b) 89 (or (> (car a) (car b)) 90 (and (= (car a) (car b)) 91 (> (cadr a) (cadr b))))))) 92 93 (list replacements cursor (string= incomplete-format "true")))) 94 95 (defun clang-format--replace (offset length &optional text) 96 "Replace the region defined by OFFSET and LENGTH with TEXT. 97 OFFSET and LENGTH are measured in bytes, not characters. OFFSET 98 is a zero-based file offset, assuming utf-8-unix coding." 99 (let ((start (clang-format--filepos-to-bufferpos offset 'exact 'utf-8-unix)) 100 (end (clang-format--filepos-to-bufferpos (+ offset length) 'exact 101 'utf-8-unix))) 102 (goto-char start) 103 (delete-region start end) 104 (when text 105 (insert text)))) 106 107 ;; bufferpos-to-filepos and filepos-to-bufferpos are new in Emacs 25.1. 108 ;; Provide fallbacks for older versions. 109 (defalias 'clang-format--bufferpos-to-filepos 110 (if (fboundp 'bufferpos-to-filepos) 111 'bufferpos-to-filepos 112 (lambda (position &optional _quality _coding-system) 113 (1- (position-bytes position))))) 114 115 (defalias 'clang-format--filepos-to-bufferpos 116 (if (fboundp 'filepos-to-bufferpos) 117 'filepos-to-bufferpos 118 (lambda (byte &optional _quality _coding-system) 119 (byte-to-position (1+ byte))))) 120 121 ;;;###autoload 122 (defun clang-format-region (start end &optional style) 123 "Use clang-format to format the code between START and END according to STYLE. 124 If called interactively uses the region or the current statement if there 125 is no active region. If no style is given uses `clang-format-style'." 126 (interactive 127 (if (use-region-p) 128 (list (region-beginning) (region-end)) 129 (list (point) (point)))) 130 131 (unless style 132 (setq style clang-format-style)) 133 134 (let ((file-start (clang-format--bufferpos-to-filepos start 'approximate 135 'utf-8-unix)) 136 (file-end (clang-format--bufferpos-to-filepos end 'approximate 137 'utf-8-unix)) 138 (cursor (clang-format--bufferpos-to-filepos (point) 'exact 'utf-8-unix)) 139 (temp-buffer (generate-new-buffer " *clang-format-temp*")) 140 (temp-file (make-temp-file "clang-format")) 141 ;; Output is XML, which is always UTF-8. Input encoding should match 142 ;; the encoding used to convert between buffer and file positions, 143 ;; otherwise the offsets calculated above are off. For simplicity, we 144 ;; always use utf-8-unix and ignore the buffer coding system. 145 (default-process-coding-system '(utf-8-unix . utf-8-unix))) 146 (unwind-protect 147 (let ((status (call-process-region 148 nil nil clang-format-executable 149 nil `(,temp-buffer ,temp-file) nil 150 151 "-output-replacements-xml" 152 "-assume-filename" (or (buffer-file-name) "") 153 "-style" style 154 "-offset" (number-to-string file-start) 155 "-length" (number-to-string (- file-end file-start)) 156 "-cursor" (number-to-string cursor))) 157 (stderr (with-temp-buffer 158 (unless (zerop (cadr (insert-file-contents temp-file))) 159 (insert ": ")) 160 (buffer-substring-no-properties 161 (point-min) (line-end-position))))) 162 (cond 163 ((stringp status) 164 (error "(clang-format killed by signal %s%s)" status stderr)) 165 ((not (zerop status)) 166 (error "(clang-format failed with code %d%s)" status stderr))) 167 168 (cl-destructuring-bind (replacements cursor incomplete-format) 169 (with-current-buffer temp-buffer 170 (clang-format--extract (car (xml-parse-region)))) 171 (save-excursion 172 (dolist (rpl replacements) 173 (apply #'clang-format--replace rpl))) 174 (when cursor 175 (goto-char (clang-format--filepos-to-bufferpos cursor 'exact 176 'utf-8-unix))) 177 (if incomplete-format 178 (message "(clang-format: incomplete (syntax errors)%s)" stderr) 179 (message "(clang-format: success%s)" stderr)))) 180 (delete-file temp-file) 181 (when (buffer-name temp-buffer) (kill-buffer temp-buffer))))) 182 183 ;;;###autoload 184 (defun clang-format-buffer (&optional style) 185 "Use clang-format to format the current buffer according to STYLE." 186 (interactive) 187 (clang-format-region (point-min) (point-max) style)) 188 189 ;;;###autoload 190 (defalias 'clang-format 'clang-format-region) 191 192 (provide 'clang-format) 193 ;;; clang-format.el ends here 194
