tools/vim/chromium.ycm_extra_conf.py

   1 # Copyright (c) 2012 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 # Autocompletion config for YouCompleteMe in Chromium.
   6 #
   7 # USAGE:
   8 #
   9 #   1. Install YCM [https://github.com/Valloric/YouCompleteMe]
  10 #          (Googlers should check out [go/ycm])
  11 #
  12 #   2. Point to this config file in your .vimrc:
  13 #          let g:ycm_global_ycm_extra_conf =
  14 #              '<chrome_depot>/src/tools/vim/chromium.ycm_extra_conf.py'
  15 #
  16 #   3. Profit
  17 #
  18 #
  19 # Usage notes:
  20 #
  21 #   * You must use ninja & clang to build Chromium.
  22 #
  23 #   * You must have run gyp_chromium and built Chromium recently.
  24 #
  25 #
  26 # Hacking notes:
  27 #
  28 #   * The purpose of this script is to construct an accurate enough command line
  29 #     for YCM to pass to clang so it can build and extract the symbols.
  30 #
  31 #   * Right now, we only pull the -I and -D flags. That seems to be sufficient
  32 #     for everything I've used it for.
  33 #
  34 #   * That whole ninja & clang thing? We could support other configs if someone
  35 #     were willing to write the correct commands and a parser.
  36 #
  37 #   * This has only been tested on gPrecise.
  38
  39
  40 import os
  41 import os.path
  42 import subprocess
  43 import sys
  44
  45
  46 # Flags from YCM's default config.
  47 flags = [
  48 '-DUSE_CLANG_COMPLETER',
  49 '-std=c++11',
  50 '-x',
  51 'c++',
  52 ]
  53
  54
  55 def PathExists(*args):
  56   return os.path.exists(os.path.join(*args))
  57
  58
  59 def FindChromeSrcFromFilename(filename):
  60   """Searches for the root of the Chromium checkout.
  61
  62   Simply checks parent directories until it finds .gclient and src/.
  63
  64   Args:
  65     filename: (String) Path to source file being edited.
  66
  67   Returns:
  68     (String) Path of 'src/', or None if unable to find.
  69   """
  70   curdir = os.path.normpath(os.path.dirname(filename))
  71   while not (PathExists(curdir, 'src') and PathExists(curdir, 'src', 'DEPS')
  72              and (PathExists(curdir, '.gclient')
  73                   or PathExists(curdir, 'src', '.git'))):
  74     nextdir = os.path.normpath(os.path.join(curdir, '..'))
  75     if nextdir == curdir:
  76       return None
  77     curdir = nextdir
  78   return os.path.join(curdir, 'src')
  79
  80
  81 def GetClangCommandFromNinjaForFilename(chrome_root, filename):
  82   """Returns the command line to build |filename|.
  83
  84   Asks ninja how it would build the source file. If the specified file is a
  85   header, tries to find its companion source file first.
  86
  87   Args:
  88     chrome_root: (String) Path to src/.
  89     filename: (String) Path to source file being edited.
  90
  91   Returns:
  92     (List of Strings) Command line arguments for clang.
  93   """
  94   if not chrome_root:
  95     return []
  96
  97   # Generally, everyone benefits from including Chromium's src/, because all of
  98   # Chromium's includes are relative to that.
  99   chrome_flags = ['-I' + os.path.join(chrome_root)]
 100
 101   # Version of Clang used to compile Chromium can be newer then version of
 102   # libclang that YCM uses for completion. So it's possible that YCM's libclang
 103   # doesn't know about some used warning options, which causes compilation
 104   # warnings (and errors, because of '-Werror');
 105   chrome_flags.append('-Wno-unknown-warning-option')
 106
 107   # Default file to get a reasonable approximation of the flags for a Blink
 108   # file.
 109   blink_root = os.path.join(chrome_root, 'third_party', 'WebKit')
 110   default_blink_file = os.path.join(blink_root, 'Source', 'core', 'Init.cpp')
 111
 112   # Header files can't be built. Instead, try to match a header file to its
 113   # corresponding source file.
 114   if filename.endswith('.h'):
 115     # Add config.h to Blink headers, which won't have it by default.
 116     if filename.startswith(blink_root):
 117       chrome_flags.append('-include')
 118       chrome_flags.append(os.path.join(blink_root, 'Source', 'config.h'))
 119
 120     alternates = ['.cc', '.cpp']
 121     for alt_extension in alternates:
 122       alt_name = filename[:-2] + alt_extension
 123       if os.path.exists(alt_name):
 124         filename = alt_name
 125         break
 126     else:
 127       if filename.startswith(blink_root):
 128         # If this is a Blink file, we can at least try to get a reasonable
 129         # approximation.
 130         filename = default_blink_file
 131       else:
 132         # If this is a standalone .h file with no source, the best we can do is
 133         # try to use the default flags.
 134         return chrome_flags
 135
 136   sys.path.append(os.path.join(chrome_root, 'tools', 'vim'))
 137   from ninja_output import GetNinjaOutputDirectory
 138   out_dir = os.path.realpath(GetNinjaOutputDirectory(chrome_root))
 139
 140   # Ninja needs the path to the source file relative to the output build
 141   # directory.
 142   rel_filename = os.path.relpath(os.path.realpath(filename), out_dir)
 143
 144   # Ask ninja how it would build our source file.
 145   p = subprocess.Popen(['ninja', '-v', '-C', out_dir, '-t',
 146                         'commands', rel_filename + '^'],
 147                        stdout=subprocess.PIPE)
 148   stdout, stderr = p.communicate()
 149   if p.returncode:
 150     return chrome_flags
 151
 152   # Ninja might execute several commands to build something. We want the last
 153   # clang command.
 154   clang_line = None
 155   for line in reversed(stdout.split('\n')):
 156     if 'clang' in line:
 157       clang_line = line
 158       break
 159   else:
 160     return chrome_flags
 161
 162   # Parse flags that are important for YCM's purposes.
 163   for flag in clang_line.split(' '):
 164     if flag.startswith('-I'):
 165       # Relative paths need to be resolved, because they're relative to the
 166       # output dir, not the source.
 167       if flag[2] == '/':
 168         chrome_flags.append(flag)
 169       else:
 170         abs_path = os.path.normpath(os.path.join(out_dir, flag[2:]))
 171         chrome_flags.append('-I' + abs_path)
 172     elif flag.startswith('-std'):
 173       chrome_flags.append(flag)
 174     elif flag.startswith('-') and flag[1] in 'DWFfmO':
 175       if flag == '-Wno-deprecated-register' or flag == '-Wno-header-guard':
 176         # These flags causes libclang (3.3) to crash. Remove it until things
 177         # are fixed.
 178         continue
 179       chrome_flags.append(flag)
 180
 181   return chrome_flags
 182
 183
 184 def FlagsForFile(filename):
 185   """This is the main entry point for YCM. Its interface is fixed.
 186
 187   Args:
 188     filename: (String) Path to source file being edited.
 189
 190   Returns:
 191     (Dictionary)
 192       'flags': (List of Strings) Command line flags.
 193       'do_cache': (Boolean) True if the result should be cached.
 194   """
 195   chrome_root = FindChromeSrcFromFilename(filename)
 196   chrome_flags = GetClangCommandFromNinjaForFilename(chrome_root,
 197                                                      filename)
 198   final_flags = flags + chrome_flags
 199
 200   return {
 201     'flags': final_flags,
 202     'do_cache': True
 203   }