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;; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 7;;; Commentary: 8 9;; This package allows to filter code through clang-format to fix its formatting. 10;; clang-format is a tool that formats C/C++/Obj-C code according to a set of 11;; style options, see <http://clang.llvm.org/docs/ClangFormatStyleOptions.html>. 12;; Note that clang-format 3.4 or newer is required. 13 14;; clang-format.el is available via MELPA and can be installed via 15;; 16;; M-x package-install clang-format 17;; 18;; when ("melpa" . "http://melpa.org/packages/") is included in 19;; `package-archives'. Alternatively, ensure the directory of this 20;; file is in your `load-path' and add 21;; 22;; (require 'clang-format) 23;; 24;; to your .emacs configuration. 25 26;; You may also want to bind `clang-format-region' to a key: 27;; 28;; (global-set-key [C-M-tab] 'clang-format-region) 29 30;;; Code: 31 32(require 'cl-lib) 33(require 'xml) 34 35(defgroup clang-format nil 36 "Format code using clang-format." 37 :group 'tools) 38 39(defcustom clang-format-executable 40 (or (executable-find "clang-format") 41 "clang-format") 42 "Location of the clang-format executable. 43 44A string containing the name or the full path of the executable." 45 :group 'clang-format 46 :type '(file :must-match t) 47 :risky t) 48 49(defcustom clang-format-style nil 50 "Style argument to pass to clang-format. 51 52By default clang-format will load the style configuration from 53a file named .clang-format located in one of the parent directories 54of the buffer." 55 :group 'clang-format 56 :type '(choice (string) (const nil)) 57 :safe #'stringp) 58(make-variable-buffer-local 'clang-format-style) 59 60(defun clang-format--extract (xml-node) 61 "Extract replacements and cursor information from XML-NODE." 62 (unless (and (listp xml-node) (eq (xml-node-name xml-node) 'replacements)) 63 (error "Expected <replacements> node")) 64 (let ((nodes (xml-node-children xml-node)) 65 (incomplete-format (xml-get-attribute xml-node 'incomplete_format)) 66 replacements 67 cursor) 68 (dolist (node nodes) 69 (when (listp node) 70 (let* ((children (xml-node-children node)) 71 (text (car children))) 72 (cl-case (xml-node-name node) 73 ('replacement 74 (let* ((offset (xml-get-attribute-or-nil node 'offset)) 75 (length (xml-get-attribute-or-nil node 'length))) 76 (when (or (null offset) (null length)) 77 (error "<replacement> node does not have offset and length attributes")) 78 (when (cdr children) 79 (error "More than one child node in <replacement> node")) 80 81 (setq offset (string-to-number offset)) 82 (setq length (string-to-number length)) 83 (push (list offset length text) replacements))) 84 ('cursor 85 (setq cursor (string-to-number text))))))) 86 87 ;; Sort by decreasing offset, length. 88 (setq replacements (sort (delq nil replacements) 89 (lambda (a b) 90 (or (> (car a) (car b)) 91 (and (= (car a) (car b)) 92 (> (cadr a) (cadr b))))))) 93 94 (list replacements cursor (string= incomplete-format "true")))) 95 96(defun clang-format--replace (offset length &optional text) 97 "Replace the region defined by OFFSET and LENGTH with TEXT. 98OFFSET and LENGTH are measured in bytes, not characters. OFFSET 99is a zero-based file offset, assuming ‘utf-8-unix’ coding." 100 (let ((start (clang-format--filepos-to-bufferpos offset 'exact 'utf-8-unix)) 101 (end (clang-format--filepos-to-bufferpos (+ offset length) 'exact 102 'utf-8-unix))) 103 (goto-char start) 104 (delete-region start end) 105 (when text 106 (insert text)))) 107 108;; ‘bufferpos-to-filepos’ and ‘filepos-to-bufferpos’ are new in Emacs 25.1. 109;; Provide fallbacks for older versions. 110(defalias 'clang-format--bufferpos-to-filepos 111 (if (fboundp 'bufferpos-to-filepos) 112 'bufferpos-to-filepos 113 (lambda (position &optional _quality _coding-system) 114 (1- (position-bytes position))))) 115 116(defalias 'clang-format--filepos-to-bufferpos 117 (if (fboundp 'filepos-to-bufferpos) 118 'filepos-to-bufferpos 119 (lambda (byte &optional _quality _coding-system) 120 (byte-to-position (1+ byte))))) 121 122;;;###autoload 123(defun clang-format-region (start end &optional style assume-file-name) 124 "Use clang-format to format the code between START and END according to STYLE. 125If called interactively uses the region or the current statement if there is no 126no active region. If no STYLE is given uses `clang-format-style'. Use 127ASSUME-FILE-NAME to locate a style config file, if no ASSUME-FILE-NAME is given 128uses the function `buffer-file-name'." 129 (interactive 130 (if (use-region-p) 131 (list (region-beginning) (region-end)) 132 (list (point) (point)))) 133 134 (unless style 135 (setq style clang-format-style)) 136 137 (unless assume-file-name 138 (setq assume-file-name buffer-file-name)) 139 140 (let ((file-start (clang-format--bufferpos-to-filepos start 'approximate 141 'utf-8-unix)) 142 (file-end (clang-format--bufferpos-to-filepos end 'approximate 143 'utf-8-unix)) 144 (cursor (clang-format--bufferpos-to-filepos (point) 'exact 'utf-8-unix)) 145 (temp-buffer (generate-new-buffer " *clang-format-temp*")) 146 (temp-file (make-temp-file "clang-format")) 147 ;; Output is XML, which is always UTF-8. Input encoding should match 148 ;; the encoding used to convert between buffer and file positions, 149 ;; otherwise the offsets calculated above are off. For simplicity, we 150 ;; always use ‘utf-8-unix’ and ignore the buffer coding system. 151 (default-process-coding-system '(utf-8-unix . utf-8-unix))) 152 (unwind-protect 153 (let ((status (apply #'call-process-region 154 nil nil clang-format-executable 155 nil `(,temp-buffer ,temp-file) nil 156 `("-output-replacements-xml" 157 ;; Guard against a nil assume-file-name. 158 ;; If the clang-format option -assume-filename 159 ;; is given a blank string it will crash as per 160 ;; the following bug report 161 ;; https://bugs.llvm.org/show_bug.cgi?id=34667 162 ,@(and assume-file-name 163 (list "-assume-filename" assume-file-name)) 164 ,@(and style (list "-style" style)) 165 "-offset" ,(number-to-string file-start) 166 "-length" ,(number-to-string (- file-end file-start)) 167 "-cursor" ,(number-to-string cursor)))) 168 (stderr (with-temp-buffer 169 (unless (zerop (cadr (insert-file-contents temp-file))) 170 (insert ": ")) 171 (buffer-substring-no-properties 172 (point-min) (line-end-position))))) 173 (cond 174 ((stringp status) 175 (error "(clang-format killed by signal %s%s)" status stderr)) 176 ((not (zerop status)) 177 (error "(clang-format failed with code %d%s)" status stderr))) 178 179 (cl-destructuring-bind (replacements cursor incomplete-format) 180 (with-current-buffer temp-buffer 181 (clang-format--extract (car (xml-parse-region)))) 182 (save-excursion 183 (dolist (rpl replacements) 184 (apply #'clang-format--replace rpl))) 185 (when cursor 186 (goto-char (clang-format--filepos-to-bufferpos cursor 'exact 187 'utf-8-unix))) 188 (if incomplete-format 189 (message "(clang-format: incomplete (syntax errors)%s)" stderr) 190 (message "(clang-format: success%s)" stderr)))) 191 (delete-file temp-file) 192 (when (buffer-name temp-buffer) (kill-buffer temp-buffer))))) 193 194;;;###autoload 195(defun clang-format-buffer (&optional style assume-file-name) 196 "Use clang-format to format the current buffer according to STYLE. 197If no STYLE is given uses `clang-format-style'. Use ASSUME-FILE-NAME 198to locate a style config file. If no ASSUME-FILE-NAME is given uses 199the function `buffer-file-name'." 200 (interactive) 201 (clang-format-region (point-min) (point-max) style assume-file-name)) 202 203;;;###autoload 204(defalias 'clang-format 'clang-format-region) 205 206(provide 'clang-format) 207;;; clang-format.el ends here 208