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;;; company-clang.el --- company-mode completion backend for Clang -*- lexical-binding: t -*-
;; Copyright (C) 2009, 2011, 2013-2017 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/>.
;;; Commentary:
;;
;;; Code:
(require 'company)
(require 'company-template)
(require 'cl-lib)
(defgroup company-clang nil
"Completion backend for Clang."
:group 'company)
(defcustom company-clang-executable
(executable-find "clang")
"Location of clang executable."
:type 'file)
(defcustom company-clang-begin-after-member-access t
"When non-nil, automatic completion will start whenever the current
symbol is preceded by \".\", \"->\" or \"::\", ignoring
`company-minimum-prefix-length'.
If `company-begin-commands' is a list, it should include `c-electric-lt-gt'
and `c-electric-colon', for automatic completion right after \">\" and
\":\"."
:type 'boolean)
(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'."
:type '(repeat (string :tag "Argument")))
(defcustom company-clang-prefix-guesser 'company-clang-guess-prefix
"A function to determine the prefix file for the current buffer."
:type '(function :tag "Guesser function" nil))
(defvar company-clang-modes '(c-mode c++-mode objc-mode)
"Major modes which clang may complete.")
(defcustom company-clang-insert-arguments t
"When non-nil, insert function arguments as a template after completion."
:type 'boolean
:package-version '(company . "0.8.0"))
;; 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 (and file (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: Handle Pattern (syntactic hints would be neat).
;; Do we ever see OVERLOAD (or OVERRIDE)?
(defconst company-clang--completion-pattern
"^COMPLETION: \\_<\\(%s[a-zA-Z0-9_:]*\\)\\(?: : \\(.*\\)$\\)?$")
(defconst company-clang--error-buffer-name "*clang-error*")
(defun company-clang--lang-option ()
(if (eq major-mode 'objc-mode)
(if (string= "m" (file-name-extension buffer-file-name))
"objective-c" "objective-c++")
(substring (symbol-name major-mode) 0 -5)))
(defun company-clang--parse-output (prefix _objc)
(goto-char (point-min))
(let ((pattern (format company-clang--completion-pattern
(regexp-quote prefix)))
(case-fold-search nil)
lines match)
(while (re-search-forward pattern nil t)
(setq match (match-string-no-properties 1))
(unless (equal match "Pattern")
(save-match-data
(when (string-match ":" match)
(setq match (substring match 0 (match-beginning 0)))))
(let ((meta (match-string-no-properties 2)))
(when (and meta (not (string= match meta)))
(put-text-property 0 1 'meta
(company-clang--strip-formatting meta)
match)))
(push match lines)))
lines))
(defun company-clang--meta (candidate)
(get-text-property 0 'meta candidate))
(defun company-clang--annotation (candidate)
(let ((ann (company-clang--annotation-1 candidate)))
(if (not (and ann (string-prefix-p "(*)" ann)))
ann
(with-temp-buffer
(insert ann)
(search-backward ")")
(let ((pt (1+ (point))))
(re-search-forward ".\\_>" nil t)
(delete-region pt (point)))
(buffer-string)))))
(defun company-clang--annotation-1 (candidate)
(let ((meta (company-clang--meta candidate)))
(cond
((null meta) nil)
((string-match "[^:]:[^:]" meta)
(substring meta (1+ (match-beginning 0))))
((string-match "(anonymous)" meta) nil)
((string-match "\\((.*)[ a-z]*\\'\\)" meta)
(let ((paren (match-beginning 1)))
(if (not (eq (aref meta (1- paren)) ?>))
(match-string 1 meta)
(with-temp-buffer
(insert meta)
(goto-char paren)
(substring meta (1- (search-backward "<"))))))))))
(defun company-clang--strip-formatting (text)
(replace-regexp-in-string
"#]" " "
(replace-regexp-in-string "[<{[]#\\|#[>}]" "" text t)
t))
(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 ""))
(message-truncate-lines t)
(err (if (re-search-forward pattern nil t)
(buffer-substring-no-properties (point-min)
(1- (match-beginning 0)))
;; Warn the user more aggressively if no match was found.
(message "clang failed with error %d: %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--start-process (prefix callback &rest args)
(let* ((objc (derived-mode-p 'objc-mode))
(buf (get-buffer-create "*clang-output*"))
;; Looks unnecessary in Emacs 25.1 and later.
(process-adaptive-read-buffering nil)
(existing-process (get-buffer-process buf)))
(when existing-process
(kill-process existing-process))
(with-current-buffer buf
(erase-buffer)
(setq buffer-undo-list t))
(let* ((process-connection-type nil)
(process (apply #'start-file-process "company-clang" buf
company-clang-executable args)))
(set-process-sentinel
process
(lambda (proc status)
(unless (string-match-p "hangup\\|killed" status)
(funcall
callback
(let ((res (process-exit-status proc)))
(with-current-buffer buf
(unless (eq 0 res)
(company-clang--handle-error res args))
;; Still try to get any useful input.
(company-clang--parse-output prefix objc)))))))
(unless (company-clang--auto-save-p)
(send-region process (point-min) (point-max))
(send-string process "\n")
(process-send-eof process)))))
(defsubst company-clang--build-location (pos)
(save-excursion
(goto-char pos)
(format "%s:%d:%d"
(if (company-clang--auto-save-p) buffer-file-name "-")
(line-number-at-pos)
(1+ (length
(encode-coding-region
(line-beginning-position)
(point)
'utf-8
t))))))
(defsubst company-clang--build-complete-args (pos)
(append '("-fsyntax-only" "-Xclang" "-code-completion-macros")
(unless (company-clang--auto-save-p)
(list "-x" (company-clang--lang-option)))
company-clang-arguments
(when (stringp company-clang--prefix)
(list "-include" (expand-file-name company-clang--prefix)))
(list "-Xclang" (format "-code-completion-at=%s"
(company-clang--build-location pos)))
(list (if (company-clang--auto-save-p) buffer-file-name "-"))))
(defun company-clang--candidates (prefix callback)
(and (company-clang--auto-save-p)
(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--start-process
prefix
callback
(company-clang--build-complete-args
(if (company-clang--check-version 4.0 9.0)
(point)
(- (point) (length prefix))))))
(defun company-clang--prefix ()
(if company-clang-begin-after-member-access
(company-grab-symbol-cons "\\.\\|->\\|::" 2)
(company-grab-symbol)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defconst company-clang-required-version 1.1)
(defvar company-clang--version nil)
(defun company-clang--auto-save-p ()
(not
(company-clang--check-version 2.9 3.1)))
(defun company-clang--check-version (min apple-min)
(pcase company-clang--version
(`(apple . ,ver) (>= ver apple-min))
(`(normal . ,ver) (>= ver min))
(_ (error "pcase-exhaustive is not in Emacs 24.3!"))))
(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))
(if (re-search-forward "\\(clang\\|Apple LLVM\\) version \\([0-9.]+\\)" nil t)
(cons
(if (equal (match-string-no-properties 1) "Apple LLVM")
'apple
'normal)
(string-to-number (match-string-no-properties 2)))
0)))
(defun company-clang (command &optional arg &rest ignored)
"`company-mode' completion backend for Clang.
Clang is a parser for C and ObjC. Clang version 1.1 or newer 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'.
With Clang versions before 2.9, we have to save the buffer before
performing completion. With Clang 2.9 and later, buffer contents are
passed via standard input."
(interactive (list 'interactive))
(cl-case command
(interactive (company-begin-backend 'company-clang))
(init (when (memq major-mode company-clang-modes)
(unless company-clang-executable
(error "Company found no clang executable"))
(setq company-clang--version (company-clang-version))
(unless (company-clang--check-version
company-clang-required-version
company-clang-required-version)
(error "Company requires clang version %s"
company-clang-required-version))))
(prefix (and (memq major-mode company-clang-modes)
buffer-file-name
company-clang-executable
(not (company-in-string-or-comment))
(or (company-clang--prefix) 'stop)))
(candidates (cons :async
(lambda (cb) (company-clang--candidates arg cb))))
(meta (company-clang--meta arg))
(annotation (company-clang--annotation arg))
(post-completion (let ((anno (company-clang--annotation arg)))
(when (and company-clang-insert-arguments anno)
(insert anno)
(if (string-match "\\`:[^:]" anno)
(company-template-objc-templatify anno)
(company-template-c-like-templatify
(concat arg anno))))))))
(provide 'company-clang)
;;; company-clang.el ends here
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