[Vim/YCM] Identify ObjC and ObjC++ headers.

tools/vim/chromium.ycm_extra_conf.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Autocompletion config for YouCompleteMe in Chromium.
 #
 # USAGE:
 #
 #   1. Install YCM [https://github.com/Valloric/YouCompleteMe]
 #          (Googlers should check out [go/ycm])
@@ skipping 45 matching lines @@
 import sys
 
 # Flags from YCM's default config.
 _default_flags = [
   '-DUSE_CLANG_COMPLETER',
   '-std=c++11',
   '-x',
   'c++',
 ]
 
+_header_alternates = ('.cc', '.cpp', '.c', '.mm', '.m')
+
 _extension_flags = {
   '.m': ['-x', 'objective-c'],
   '.mm': ['-x', 'objective-c++'],
 }
 
 def PathExists(*args):
   return os.path.exists(os.path.join(*args))
 
 
 def FindChromeSrcFromFilename(filename):
@@ skipping 34 matching lines @@
   """
   blink_root = os.path.join(chrome_root, 'third_party', 'WebKit')
   if filename.startswith(blink_root):
     return os.path.join(blink_root, 'Source', 'core', 'Init.cpp')
   else:
     if 'test.' in filename:
       return os.path.join(chrome_root, 'base', 'logging_unittest.cc')
     return os.path.join(chrome_root, 'base', 'logging.cc')
 
 
-def GetBuildableSourceFile(chrome_root, filename):
-  """Returns a buildable source file corresponding to |filename|.
-
-  A buildable source file is one which is likely to be passed into clang as a
-  source file during the build. For .h files, returns the closest matching .cc,
-  .cpp or .c file. If no such file is found, returns the same as
-  GetDefaultSourceFile().
-
-  Args:
-    chrome_root: (String) Absolute path to the root of Chromium checkout.
-    filename: (String) Absolute path to the target source file.
-
-  Returns:
-    (String) Absolute path to source file.
-  """
-  if filename.endswith('.h'):
-    # Header files can't be built. Instead, try to match a header file to its
-    # corresponding source file.
-    alternates = ['.cc', '.cpp', '.c']
-    for alt_extension in alternates:
-      alt_name = filename[:-2] + alt_extension
-      if os.path.exists(alt_name):
-        return alt_name
-
-    return GetDefaultSourceFile(chrome_root, filename)
-
-  return filename
-
-
 def GetNinjaBuildOutputsForSourceFile(out_dir, filename):
   """Returns a list of build outputs for filename.
 
   The list is generated by invoking 'ninja -t query' tool to retrieve a list of
   inputs and outputs of |filename|. This list is then filtered to only include
   .o and .obj outputs.
 
   Args:
     out_dir: (String) Absolute path to ninja build output directory.
     filename: (String) Absolute path to source file.
@@ skipping 160 matching lines @@
   # Version of Clang used to compile Chromium can be newer then version of
   # libclang that YCM uses for completion. So it's possible that YCM's libclang
   # doesn't know about some used warning options, which causes compilation
   # warnings (and errors, because of '-Werror');
   additional_flags.append('-Wno-unknown-warning-option')
 
   sys.path.append(os.path.join(chrome_root, 'tools', 'vim'))
   from ninja_output import GetNinjaOutputDirectory
   out_dir = GetNinjaOutputDirectory(chrome_root)
 
-  clang_line = GetClangCommandLineFromNinjaForSource(
-      out_dir, GetBuildableSourceFile(chrome_root, filename))
+  basename, extension = os.path.splitext(filename)
+  if extension == '.h':
+    candidates = [basename + ext for ext in _header_alternates]
+  else:
+    candidates = [filename]
+
+  clang_line = None
+  buildable_extension = extension
+  for candidate in candidates:
+    clang_line = GetClangCommandLineFromNinjaForSource(out_dir, candidate)
+    if clang_line:
+      buildable_extension = os.path.splitext(candidate)[1]
+      break
+
+  additional_flags += _extension_flags.get(buildable_extension, [])
+
   if not clang_line:
     # If ninja didn't know about filename or it's companion files, then try a
     # default build target. It is possible that the file is new, or build.ninja
     # is stale.
     clang_line = GetClangCommandLineFromNinjaForSource(
         out_dir, GetDefaultSourceFile(chrome_root, filename))
 
   if not clang_line:
     return additional_flags
 
   return GetClangOptionsFromCommandLine(clang_line, out_dir, additional_flags)
 
 
 def FlagsForFile(filename):
   """This is the main entry point for YCM. Its interface is fixed.
 
   Args:
     filename: (String) Path to source file being edited.
 
   Returns:
     (Dictionary)
       'flags': (List of Strings) Command line flags.
       'do_cache': (Boolean) True if the result should be cached.
   """
-  ext = os.path.splitext(filename)[1]
   abs_filename = os.path.abspath(filename)
   chrome_root = FindChromeSrcFromFilename(abs_filename)
   clang_flags = GetClangOptionsFromNinjaForFilename(chrome_root, abs_filename)
 
   # If clang_flags could not be determined, then assume that was due to a
   # transient failure. Preventing YCM from caching the flags allows us to try to
   # determine the flags again.
   should_cache_flags_for_file = bool(clang_flags)
 
-  final_flags = _default_flags + _extension_flags.get(ext, []) + clang_flags
+  final_flags = _default_flags + clang_flags
 
   return {
     'flags': final_flags,
     'do_cache': should_cache_flags_for_file
   }