| ;;; clang-format.el --- Format code using clang-format -*- lexical-binding: t; -*- |
| |
| ;; Keywords: tools, c |
| ;; Package-Requires: ((cl-lib "0.3")) |
| ;; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| |
| ;;; Commentary: |
| |
| ;; This package allows to filter code through clang-format to fix its formatting. |
| ;; clang-format is a tool that formats C/C++/Obj-C code according to a set of |
| ;; style options, see <http://clang.llvm.org/docs/ClangFormatStyleOptions.html>. |
| ;; Note that clang-format 3.4 or newer is required. |
| |
| ;; clang-format.el is available via MELPA and can be installed via |
| ;; |
| ;; M-x package-install clang-format |
| ;; |
| ;; when ("melpa" . "http://melpa.org/packages/") is included in |
| ;; `package-archives'. Alternatively, ensure the directory of this |
| ;; file is in your `load-path' and add |
| ;; |
| ;; (require 'clang-format) |
| ;; |
| ;; to your .emacs configuration. |
| |
| ;; You may also want to bind `clang-format-region' to a key: |
| ;; |
| ;; (global-set-key [C-M-tab] 'clang-format-region) |
| |
| ;;; Code: |
| |
| (require 'cl-lib) |
| (require 'xml) |
| |
| (defgroup clang-format nil |
| "Format code using clang-format." |
| :group 'tools) |
| |
| (defcustom clang-format-executable |
| (or (executable-find "clang-format") |
| "clang-format") |
| "Location of the clang-format executable. |
| |
| A string containing the name or the full path of the executable." |
| :group 'clang-format |
| :type '(file :must-match t) |
| :risky t) |
| |
| (defcustom clang-format-style nil |
| "Style argument to pass to clang-format. |
| |
| By default clang-format will load the style configuration from |
| a file named .clang-format located in one of the parent directories |
| of the buffer." |
| :group 'clang-format |
| :type '(choice (string) (const nil)) |
| :safe #'stringp) |
| (make-variable-buffer-local 'clang-format-style) |
| |
| (defcustom clang-format-fallback-style "none" |
| "Fallback style to pass to clang-format. |
| |
| This style will be used if clang-format-style is set to \"file\" |
| and no .clang-format is found in the directory of the buffer or |
| one of parent directories. Set to \"none\" to disable formatting |
| in such buffers." |
| :group 'clang-format |
| :type 'string |
| :safe #'stringp) |
| (make-variable-buffer-local 'clang-format-fallback-style) |
| |
| (defun clang-format--extract (xml-node) |
| "Extract replacements and cursor information from XML-NODE." |
| (unless (and (listp xml-node) (eq (xml-node-name xml-node) 'replacements)) |
| (error "Expected <replacements> node")) |
| (let ((nodes (xml-node-children xml-node)) |
| (incomplete-format (xml-get-attribute xml-node 'incomplete_format)) |
| replacements |
| cursor) |
| (dolist (node nodes) |
| (when (listp node) |
| (let* ((children (xml-node-children node)) |
| (text (car children))) |
| (cl-case (xml-node-name node) |
| ('replacement |
| (let* ((offset (xml-get-attribute-or-nil node 'offset)) |
| (length (xml-get-attribute-or-nil node 'length))) |
| (when (or (null offset) (null length)) |
| (error "<replacement> node does not have offset and length attributes")) |
| (when (cdr children) |
| (error "More than one child node in <replacement> node")) |
| |
| (setq offset (string-to-number offset)) |
| (setq length (string-to-number length)) |
| (push (list offset length text) replacements))) |
| ('cursor |
| (setq cursor (string-to-number text))))))) |
| |
| ;; Sort by decreasing offset, length. |
| (setq replacements (sort (delq nil replacements) |
| (lambda (a b) |
| (or (> (car a) (car b)) |
| (and (= (car a) (car b)) |
| (> (cadr a) (cadr b))))))) |
| |
| (list replacements cursor (string= incomplete-format "true")))) |
| |
| (defun clang-format--replace (offset length &optional text) |
| "Replace the region defined by OFFSET and LENGTH with TEXT. |
| OFFSET and LENGTH are measured in bytes, not characters. OFFSET |
| is a zero-based file offset, assuming ‘utf-8-unix’ coding." |
| (let ((start (clang-format--filepos-to-bufferpos offset 'exact 'utf-8-unix)) |
| (end (clang-format--filepos-to-bufferpos (+ offset length) 'exact |
| 'utf-8-unix))) |
| (goto-char start) |
| (delete-region start end) |
| (when text |
| (insert text)))) |
| |
| ;; ‘bufferpos-to-filepos’ and ‘filepos-to-bufferpos’ are new in Emacs 25.1. |
| ;; Provide fallbacks for older versions. |
| (defalias 'clang-format--bufferpos-to-filepos |
| (if (fboundp 'bufferpos-to-filepos) |
| 'bufferpos-to-filepos |
| (lambda (position &optional _quality _coding-system) |
| (1- (position-bytes position))))) |
| |
| (defalias 'clang-format--filepos-to-bufferpos |
| (if (fboundp 'filepos-to-bufferpos) |
| 'filepos-to-bufferpos |
| (lambda (byte &optional _quality _coding-system) |
| (byte-to-position (1+ byte))))) |
| |
| ;;;###autoload |
| (defun clang-format-region (start end &optional style assume-file-name) |
| "Use clang-format to format the code between START and END according to STYLE. |
| If called interactively uses the region or the current statement if there is no |
| no active region. If no STYLE is given uses `clang-format-style'. Use |
| ASSUME-FILE-NAME to locate a style config file, if no ASSUME-FILE-NAME is given |
| uses the function `buffer-file-name'." |
| (interactive |
| (if (use-region-p) |
| (list (region-beginning) (region-end)) |
| (list (point) (point)))) |
| |
| (unless style |
| (setq style clang-format-style)) |
| |
| (unless assume-file-name |
| (setq assume-file-name buffer-file-name)) |
| |
| (let ((file-start (clang-format--bufferpos-to-filepos start 'approximate |
| 'utf-8-unix)) |
| (file-end (clang-format--bufferpos-to-filepos end 'approximate |
| 'utf-8-unix)) |
| (cursor (clang-format--bufferpos-to-filepos (point) 'exact 'utf-8-unix)) |
| (temp-buffer (generate-new-buffer " *clang-format-temp*")) |
| (temp-file (make-temp-file "clang-format")) |
| ;; Output is XML, which is always UTF-8. Input encoding should match |
| ;; the encoding used to convert between buffer and file positions, |
| ;; otherwise the offsets calculated above are off. For simplicity, we |
| ;; always use ‘utf-8-unix’ and ignore the buffer coding system. |
| (default-process-coding-system '(utf-8-unix . utf-8-unix))) |
| (unwind-protect |
| (let ((status (apply #'call-process-region |
| nil nil clang-format-executable |
| nil `(,temp-buffer ,temp-file) nil |
| `("-output-replacements-xml" |
| ;; Guard against a nil assume-file-name. |
| ;; If the clang-format option -assume-filename |
| ;; is given a blank string it will crash as per |
| ;; the following bug report |
| ;; https://bugs.llvm.org/show_bug.cgi?id=34667 |
| ,@(and assume-file-name |
| (list "-assume-filename" assume-file-name)) |
| ,@(and style (list "-style" style)) |
| "-fallback-style" ,clang-format-fallback-style |
| "-offset" ,(number-to-string file-start) |
| "-length" ,(number-to-string (- file-end file-start)) |
| "-cursor" ,(number-to-string cursor)))) |
| (stderr (with-temp-buffer |
| (unless (zerop (cadr (insert-file-contents temp-file))) |
| (insert ": ")) |
| (buffer-substring-no-properties |
| (point-min) (line-end-position))))) |
| (cond |
| ((stringp status) |
| (error "(clang-format killed by signal %s%s)" status stderr)) |
| ((not (zerop status)) |
| (error "(clang-format failed with code %d%s)" status stderr))) |
| |
| (cl-destructuring-bind (replacements cursor incomplete-format) |
| (with-current-buffer temp-buffer |
| (clang-format--extract (car (xml-parse-region)))) |
| (save-excursion |
| (dolist (rpl replacements) |
| (apply #'clang-format--replace rpl))) |
| (when cursor |
| (goto-char (clang-format--filepos-to-bufferpos cursor 'exact |
| 'utf-8-unix))) |
| (if incomplete-format |
| (message "(clang-format: incomplete (syntax errors)%s)" stderr) |
| (message "(clang-format: success%s)" stderr)))) |
| (delete-file temp-file) |
| (when (buffer-name temp-buffer) (kill-buffer temp-buffer))))) |
| |
| ;;;###autoload |
| (defun clang-format-buffer (&optional style assume-file-name) |
| "Use clang-format to format the current buffer according to STYLE. |
| If no STYLE is given uses `clang-format-style'. Use ASSUME-FILE-NAME |
| to locate a style config file. If no ASSUME-FILE-NAME is given uses |
| the function `buffer-file-name'." |
| (interactive) |
| (clang-format-region (point-min) (point-max) style assume-file-name)) |
| |
| ;;;###autoload |
| (defalias 'clang-format 'clang-format-region) |
| |
| (provide 'clang-format) |
| ;;; clang-format.el ends here |