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 subprocess
  42
  43
  44 # Flags from YCM's default config.
  45 flags = [
  46 '-DUSE_CLANG_COMPLETER',
  47 '-std=c++11',
  48 '-x',
  49 'c++',
  50 ]
  51
  52
  53 def PathExists(*args):
  54   return os.path.exists(os.path.join(*args))
  55
  56
  57 def FindChromeSrcFromFilename(filename):
  58   """Searches for the root of the Chromium checkout.
  59
  60   Simply checks parent directories until it finds .gclient and src/.
  61
  62   Args:
  63     filename: (String) Path to source file being edited.
  64
  65   Returns:
  66     (String) Path of 'src/', or None if unable to find.
  67   """
  68   curdir = os.path.normpath(os.path.dirname(filename))
  69   while not (PathExists(curdir, 'src') and PathExists(curdir, 'src', 'DEPS')
  70              and (PathExists(curdir, '.gclient')
  71                   or PathExists(curdir, 'src', '.git'))):
  72     nextdir = os.path.normpath(os.path.join(curdir, '..'))
  73     if nextdir == curdir:
  74       return None
  75     curdir = nextdir
  76   return os.path.join(curdir, 'src')
  77
  78
  79 # Largely copied from ninja-build.vim (guess_configuration)
  80 def GetNinjaOutputDirectory(chrome_root):
  81   """Returns <chrome_root>/<output_dir>/(Release|Debug).
  82
  83   The configuration chosen is the one most recently generated/built. Detects
  84   a custom output_dir specified by GYP_GENERATOR_FLAGS."""
  85
  86   output_dir = 'out'
  87   generator_flags = os.getenv('GYP_GENERATOR_FLAGS', '').split(' ')
  88   for flag in generator_flags:
  89     name_value = flag.split('=', 1)
  90     if len(name_value) == 2 and name_value[0] == 'output_dir':
  91       output_dir = name_value[1]
  92
  93   root = os.path.join(chrome_root, output_dir)
  94   debug_path = os.path.join(root, 'Debug')
  95   release_path = os.path.join(root, 'Release')
  96
  97   def is_release_15s_newer(test_path):
  98     try:
  99       debug_mtime = os.path.getmtime(os.path.join(debug_path, test_path))
 100     except os.error:
 101       debug_mtime = 0
 102     try:
 103       rel_mtime = os.path.getmtime(os.path.join(release_path, test_path))
 104     except os.error:
 105       rel_mtime = 0
 106     return rel_mtime - debug_mtime >= 15
 107
 108   if is_release_15s_newer('build.ninja') or is_release_15s_newer('protoc'):
 109     return release_path
 110   return debug_path
 111
 112
 113 def GetClangCommandFromNinjaForFilename(chrome_root, filename):
 114   """Returns the command line to build |filename|.
 115
 116   Asks ninja how it would build the source file. If the specified file is a
 117   header, tries to find its companion source file first.
 118
 119   Args:
 120     chrome_root: (String) Path to src/.
 121     filename: (String) Path to source file being edited.
 122
 123   Returns:
 124     (List of Strings) Command line arguments for clang.
 125   """
 126   if not chrome_root:
 127     return []
 128
 129   # Generally, everyone benefits from including Chromium's src/, because all of
 130   # Chromium's includes are relative to that.
 131   chrome_flags = ['-I' + os.path.join(chrome_root)]
 132
 133   # Default file to get a reasonable approximation of the flags for a Blink
 134   # file.
 135   blink_root = os.path.join(chrome_root, 'third_party', 'WebKit')
 136   default_blink_file = os.path.join(blink_root, 'Source', 'core', 'Init.cpp')
 137
 138   # Header files can't be built. Instead, try to match a header file to its
 139   # corresponding source file.
 140   if filename.endswith('.h'):
 141     # Add config.h to Blink headers, which won't have it by default.
 142     if filename.startswith(blink_root):
 143       chrome_flags.append('-include')
 144       chrome_flags.append(os.path.join(blink_root, 'Source', 'config.h'))
 145
 146     alternates = ['.cc', '.cpp']
 147     for alt_extension in alternates:
 148       alt_name = filename[:-2] + alt_extension
 149       if os.path.exists(alt_name):
 150         filename = alt_name
 151         break
 152     else:
 153       if filename.startswith(blink_root):
 154         # If this is a Blink file, we can at least try to get a reasonable
 155         # approximation.
 156         filename = default_blink_file
 157       else:
 158         # If this is a standalone .h file with no source, the best we can do is
 159         # try to use the default flags.
 160         return chrome_flags
 161
 162   # Ninja needs the path to the source file from the output build directory.
 163   # Cut off the common part and /.
 164   subdir_filename = filename[len(chrome_root)+1:]
 165   rel_filename = os.path.join('..', '..', subdir_filename)
 166
 167   out_dir = GetNinjaOutputDirectory(chrome_root)
 168
 169   # Ask ninja how it would build our source file.
 170   p = subprocess.Popen(['ninja', '-v', '-C', out_dir, '-t',
 171                         'commands', rel_filename + '^'],
 172                        stdout=subprocess.PIPE)
 173   stdout, stderr = p.communicate()
 174   if p.returncode:
 175     return chrome_flags
 176
 177   # Ninja might execute several commands to build something. We want the last
 178   # clang command.
 179   clang_line = None
 180   for line in reversed(stdout.split('\n')):
 181     if 'clang' in line:
 182       clang_line = line
 183       break
 184   else:
 185     return chrome_flags
 186
 187   # Parse flags that are important for YCM's purposes.
 188   for flag in clang_line.split(' '):
 189     if flag.startswith('-I'):
 190       # Relative paths need to be resolved, because they're relative to the
 191       # output dir, not the source.
 192       if flag[2] == '/':
 193         chrome_flags.append(flag)
 194       else:
 195         abs_path = os.path.normpath(os.path.join(out_dir, flag[2:]))
 196         chrome_flags.append('-I' + abs_path)
 197     elif flag.startswith('-std'):
 198       chrome_flags.append(flag)
 199     elif flag.startswith('-') and flag[1] in 'DWFfmO':
 200       if flag == '-Wno-deprecated-register' or flag == '-Wno-header-guard':
 201         # These flags causes libclang (3.3) to crash. Remove it until things
 202         # are fixed.
 203         continue
 204       chrome_flags.append(flag)
 205
 206   return chrome_flags
 207
 208
 209 def FlagsForFile(filename):
 210   """This is the main entry point for YCM. Its interface is fixed.
 211
 212   Args:
 213     filename: (String) Path to source file being edited.
 214
 215   Returns:
 216     (Dictionary)
 217       'flags': (List of Strings) Command line flags.
 218       'do_cache': (Boolean) True if the result should be cached.
 219   """
 220   chrome_root = FindChromeSrcFromFilename(filename)
 221   chrome_flags = GetClangCommandFromNinjaForFilename(chrome_root,
 222                                                      filename)
 223   final_flags = flags + chrome_flags
 224
 225   return {
 226     'flags': final_flags,
 227     'do_cache': True
 228   }