tools/emacs/flymake-chromium.el

   1 ;; Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 ;; Use of this source code is governed by a BSD-style license that can be
   3 ;; found in the LICENSE file.
   4
   5 ;; Set up flymake for use with chromium code.  Uses ninja (since none of the
   6 ;; other chromium build systems have latency that allows interactive use).
   7 ;;
   8 ;; Requires a modern emacs (GNU Emacs >= 23) and that gyp has already generated
   9 ;; the build.ninja file(s).  See defcustoms below for settable knobs.
  10
  11
  12 (require 'flymake)
  13
  14 (defcustom cr-flymake-ninja-build-file "out/Debug/build.ninja"
  15   "Relative path from chromium's src/ directory to the
  16   build.ninja file to use.")
  17
  18 (defcustom cr-flymake-ninja-executable "ninja"
  19   "Ninja executable location; either in $PATH or explicitly given.")
  20
  21 (defun cr-flymake-absbufferpath ()
  22   "Return the absolute path to the current buffer, or nil if the
  23   current buffer has no path."
  24   (when buffer-file-truename
  25       (expand-file-name buffer-file-truename)))
  26
  27 (defun cr-flymake-chromium-src ()
  28   "Return chromium's src/ directory, or nil on failure."
  29   (let ((srcdir (locate-dominating-file
  30                  (cr-flymake-absbufferpath) cr-flymake-ninja-build-file)))
  31     (when srcdir (expand-file-name srcdir))))
  32
  33 (defun cr-flymake-string-prefix-p (prefix str)
  34   "Return non-nil if PREFIX is a prefix of STR (23.2 has string-prefix-p but
  35   that's case insensitive and also 23.1 doesn't have it)."
  36   (string= prefix (substring str 0 (length prefix))))
  37
  38 (defun cr-flymake-current-file-name ()
  39   "Return the relative path from chromium's src/ directory to the
  40   file backing the current buffer or nil if it doesn't look like
  41   we're under chromium/src/."
  42   (when (and (cr-flymake-chromium-src)
  43              (cr-flymake-string-prefix-p
  44               (cr-flymake-chromium-src) (cr-flymake-absbufferpath)))
  45     (substring (cr-flymake-absbufferpath) (length (cr-flymake-chromium-src)))))
  46
  47 (defun cr-flymake-from-build-to-src-root ()
  48   "Return a path fragment for getting from the build.ninja file to src/."
  49   (replace-regexp-in-string
  50    "[^/]+" ".."
  51    (substring
  52     (file-name-directory
  53      (file-truename (or (and (cr-flymake-string-prefix-p
  54                               "/" cr-flymake-ninja-build-file)
  55                              cr-flymake-ninja-build-file)
  56                         (concat (cr-flymake-chromium-src)
  57                                 cr-flymake-ninja-build-file))))
  58     (length (cr-flymake-chromium-src)))))
  59
  60 (defun cr-flymake-getfname (file-name-from-error-message)
  61   "Strip cruft from the passed-in filename to help flymake find the real file."
  62   (file-name-nondirectory file-name-from-error-message))
  63
  64 (defun cr-flymake-ninja-command-line ()
  65   "Return the command-line for running ninja, as a list of strings, or nil if
  66   we're not during a save"
  67   (unless (buffer-modified-p)
  68     (list cr-flymake-ninja-executable
  69           (list "-C"
  70                 (concat (cr-flymake-chromium-src)
  71                         (file-name-directory cr-flymake-ninja-build-file))
  72                 (concat (cr-flymake-from-build-to-src-root)
  73                         (cr-flymake-current-file-name) "^")))))
  74
  75 (defun cr-flymake-kick-off-check-after-save ()
  76   "Kick off a syntax check after file save, if flymake-mode is on."
  77   (when flymake-mode (flymake-start-syntax-check)))
  78
  79 (defadvice next-error (around cr-flymake-next-error activate)
  80   "If flymake has something to say, let it say it; otherwise
  81    revert to normal next-error behavior."
  82   (if (not flymake-err-info)
  83       (condition-case msg
  84           ad-do-it
  85         (error (message "%s" (prin1-to-string msg))))
  86     (flymake-goto-next-error)
  87     ;; copy/pasted from flymake-display-err-menu-for-current-line because I
  88     ;; couldn't find a way to have it tell me what the relevant error for this
  89     ;; line was in a single call:
  90     (let* ((line-no (flymake-current-line-no))
  91            (line-err-info-list
  92             (nth 0 (flymake-find-err-info flymake-err-info line-no)))
  93            (menu-data (flymake-make-err-menu-data line-no line-err-info-list)))
  94       (prin1 (car (car (car (cdr menu-data)))) t))))
  95
  96 (defun cr-flymake-find-file ()
  97   "Enable flymake, but only if it makes sense, and immediately
  98   disable timer-based execution."
  99   (when (and (not flymake-mode)
 100              (not buffer-read-only)
 101              (cr-flymake-current-file-name))
 102     ;; Since flymake-allowed-file-name-masks requires static regexps to match
 103     ;; against, can't use cr-flymake-chromium-src here.  Instead we add a
 104     ;; generic regexp, but only to a buffer-local version of the variable.
 105     (set (make-local-variable 'flymake-allowed-file-name-masks)
 106          (list (list "\\.c\\(\\|c\\|pp\\)"
 107                      'cr-flymake-ninja-command-line
 108                      'ignore
 109                      'cr-flymake-getfname)))
 110     (flymake-find-file-hook)
 111     (if flymake-mode
 112         (cancel-timer flymake-timer)
 113       (kill-local-variable 'flymake-allowed-file-name-masks))))
 114
 115 (add-hook 'find-file-hook 'cr-flymake-find-file 'append)
 116 (add-hook 'after-save-hook 'cr-flymake-kick-off-check-after-save)
 117
 118 ;; Show flymake infrastructure ERRORs in hopes of fixing them.  Set to 3 for
 119 ;; DEBUG-level output from flymake.el.
 120 (setq flymake-log-level 0)
 121
 122 (provide 'flymake-chromium)