--- /dev/null
+;;; company-clang.el --- a company-mode completion back-end for clang
+
+;; Copyright (C) 2009 Free Software Foundation, Inc.
+
+;; Author: Nikolaj Schumacher
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'company)
+(eval-when-compile (require 'cl))
+
+(defcustom company-clang-executable
+ (executable-find "clang")
+ "*Location of clang executable"
+ :group 'company-clang
+ :type 'file)
+
+(defcustom company-clang-auto-save t
+ "*Determines whether to save the buffer when retrieving completions.
+clang can only complete correctly when the buffer has been saved."
+ :group 'company-clang
+ :type '(choice (const :tag "Off" nil)
+ (const :tag "On" t)))
+
+(defcustom company-clang-arguments nil
+ "*Additional arguments to pass to clang when completing.
+Prefix files (-include ...) can be selected with
+`company-clang-set-prefix' or automatically through a custom
+`company-clang-prefix-guesser'."
+ :group 'company-clang
+ :type '(repeat (string :tag "Argument" nil)))
+
+(defcustom company-clang-prefix-guesser 'company-clang-guess-prefix
+ "*A function to determine the prefix file for the current buffer."
+ :group 'company-clang
+ :type '(function :tag "Guesser function" nil))
+
+(defvar company-clang-modes '(c-mode objc-mode)
+ "Major modes which clang may complete.")
+
+;; prefix ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(defvar company-clang--prefix nil)
+
+(defsubst company-clang--guess-pch-file (file)
+ (let ((dir (directory-file-name (file-name-directory file))))
+ (when (equal (file-name-nondirectory dir) "Classes")
+ (setq dir (file-name-directory dir)))
+ (car (directory-files dir t "\\([^.]h\\|[^h]\\).pch\\'" t))))
+
+(defsubst company-clang--file-substring (file beg end)
+ (with-temp-buffer
+ (insert-file-contents-literally file nil beg end)
+ (buffer-string)))
+
+(defun company-clang-guess-prefix ()
+ "Try to guess the prefix file for the current buffer."
+ ;; Prefixes seem to be called .pch. Pre-compiled headers do, too.
+ ;; So we look at the magic number to rule them out.
+ (let* ((file (company-clang--guess-pch-file buffer-file-name))
+ (magic-number (company-clang--file-substring file 0 4)))
+ (unless (member magic-number '("CPCH" "gpch"))
+ file)))
+
+(defun company-clang-set-prefix (&optional prefix)
+ "Use PREFIX as a prefix (-include ...) file for clang completion."
+ (interactive (let ((def (funcall company-clang-prefix-guesser)))
+ (unless (stringp def)
+ (setq def default-directory))
+ (list (read-file-name "Prefix file: "
+ (when def (file-name-directory def))
+ def t (when def (file-name-nondirectory def))))))
+ ;; TODO: pre-compile?
+ (setq company-clang--prefix (and (stringp prefix)
+ (file-regular-p prefix)
+ prefix)))
+
+;; Clean-up on exit.
+(add-hook 'kill-emacs-hook 'company-clang-set-prefix)
+
+;; parsing ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; TODO: How to handle OVERLOAD and Pattern?
+(defconst company-clang--completion-pattern
+ "^COMPLETION: \\_<\\(%s[a-zA-Z0-9_:]*\\)")
+
+(defconst company-clang--error-buffer-name "*clang error*")
+
+(defun company-clang--parse-output (prefix)
+ (goto-char (point-min))
+ (let ((pattern (format company-clang--completion-pattern
+ (regexp-quote prefix)))
+ lines match)
+ (while (re-search-forward pattern nil t)
+ (setq match (match-string-no-properties 1))
+ (unless (equal match "Pattern")
+ (push match lines)))
+ lines))
+
+(defun company-clang--handle-error (res args)
+ (goto-char (point-min))
+ (let* ((buf (get-buffer-create company-clang--error-buffer-name))
+ (cmd (concat company-clang-executable (mapconcat 'identity args " ")))
+ (pattern (format company-clang--completion-pattern ""))
+ (err (if (re-search-forward pattern nil t)
+ (buffer-substring-no-properties (point-min)
+ (1- (match-beginning 0)))
+ ;; Warn the user more agressively if no match was found.
+ (message "clang failed with error %d:\n%s" res cmd)
+ (buffer-string))))
+
+ (with-current-buffer buf
+ (let ((inhibit-read-only t))
+ (erase-buffer)
+ (insert (current-time-string)
+ (format "\nclang failed with error %d:\n" res)
+ cmd "\n\n")
+ (insert err)
+ (setq buffer-read-only t)
+ (goto-char (point-min))))))
+
+(defun company-clang--call-process (prefix &rest args)
+ (with-temp-buffer
+ (let ((res (apply 'call-process company-clang-executable nil t nil args)))
+ (unless (eq 0 res)
+ (company-clang--handle-error res args))
+ ;; Still try to get any useful input.
+ (company-clang--parse-output prefix))))
+
+(defsubst company-clang--build-location (pos)
+ (save-excursion
+ (goto-char pos)
+ (format "%s:%d:%d" buffer-file-name (line-number-at-pos)
+ (1+ (current-column)))))
+
+(defsubst company-clang--build-complete-args (pos)
+ (append '("-cc1" "-fsyntax-only")
+ company-clang-arguments
+ (when (stringp company-clang--prefix)
+ (list "-include" (expand-file-name company-clang--prefix)))
+ '("-code-completion-at")
+ (list (company-clang--build-location pos))
+ (list buffer-file-name)))
+
+(defun company-clang--candidates (prefix)
+ (and company-clang-auto-save
+ (buffer-modified-p)
+ (basic-save-buffer))
+ (when (null company-clang--prefix)
+ (company-clang-set-prefix (or (funcall company-clang-prefix-guesser)
+ 'none)))
+ (apply 'company-clang--call-process
+ prefix
+ (company-clang--build-complete-args (- (point) (length prefix)))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(defconst company-clang-required-version "1.1")
+
+(defsubst company-clang-version ()
+ "Return the version of `company-clang-executable'."
+ (with-temp-buffer
+ (call-process company-clang-executable nil t nil "--version")
+ (goto-char (point-min))
+ (when (re-search-forward "\\`clang version \\([0-9.]+\\)" nil t)
+ (match-string-no-properties 1))))
+
+(defun company-clang-objc-templatify (selector)
+ (let* ((end (point))
+ (beg (- (point) (length selector)))
+ (templ (company-template-declare-template beg end)))
+ (save-excursion
+ (goto-char beg)
+ (while (search-forward ":" end t)
+ (replace-match ": ")
+ (incf end 2)
+ (company-template-add-field templ (1- (match-end 0)) "<arg>"))
+ (delete-char -1))
+ (company-template-move-to-first templ)))
+
+(defun company-clang (command &optional arg &rest ignored)
+ "A `company-mode' completion back-end for clang.
+Clang is a parser for C and ObjC. The unreleased development version of
+clang (1.1) is required.
+
+Additional command line arguments can be specified in
+`company-clang-arguments'. Prefix files (-include ...) can be selected
+with `company-clang-set-prefix' or automatically through a custom
+`company-clang-prefix-guesser'.
+
+Completions only work correctly when the buffer has been saved.
+`company-clang-auto-save' determines whether to do this automatically."
+ (interactive (list 'interactive))
+ (case command
+ ('interactive (company-begin-backend 'company-clang))
+ ('init (unless company-clang-executable
+ (error "Company found no clang executable"))
+ (when (version< (company-clang-version)
+ company-clang-required-version)
+ (error "Company requires clang version 1.1")))
+ ('prefix (and (memq major-mode company-clang-modes)
+ buffer-file-name
+ company-clang-executable
+ (not (company-in-string-or-comment))
+ (or (company-grab-symbol) 'stop)))
+ ('candidates (company-clang--candidates arg))
+ ('post-completion (and (derived-mode-p 'objc-mode)
+ (string-match ":" arg)
+ (company-clang-objc-templatify arg)))))
+
+(provide 'company-clang)
+;;; company-clang.el ends here