[seed] Adding support for YouCompleteMe vim plugin

[Alan Knowles <alank src gnome org>]

commit abf3a105b0fd2d48440270df359417ee64e02101
Author: Danilo Cesar Lemes de Paula <danilo cesar collabora co uk>
Date:   Fri Jan 8 17:35:04 2016 -0200

    Adding support for YouCompleteMe vim plugin
    
    YouCompleteMe is a vim/atom plugin that uses clang-completer to provide
    auto-completion, jump-to-definition and other developer tools on vim.
    
    There're a bunch of other opensource projects using it, such as firefox
    and webkit.

 .gitignore                  |    2 +
 .ycm_extra_conf.py          |  114 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+), 0 deletions(-)
---
diff --git a/.gitignore b/.gitignore
index dc86caa..2053201 100644
--- a/.gitignore
+++ b/.gitignore
@@ -207,3 +207,5 @@ modules/gettext/._gettext.c
 po/Makefile.in.in
 
 version.xml
+/compile_commands.json
+/.ycm_extra_conf.pyc
diff --git a/.ycm_extra_conf.py b/.ycm_extra_conf.py
new file mode 100644
index 0000000..06a545b
--- /dev/null
+++ b/.ycm_extra_conf.py
@@ -0,0 +1,114 @@
+# This is the default copy of the YCM file
+# To use you, you need a compile_commands.json file with inscructions to build
+# each file.
+#
+# To create that file using autotools please check https://github.com/rizsotto/Bear
+
+import os
+import ycm_core
+
+# These are the compilation flags that will be used in case there's no
+# compilation database set (by default, one is not set).
+# CHANGE THIS LIST OF FLAGS. YES, THIS IS THE DROID YOU HAVE BEEN LOOKING FOR.
+flags = [
+'-Wall',
+'-Wextra',
+'-Werror',
+]
+
+
+# Set this to the absolute path to the folder (NOT the file!) containing the
+# compile_commands.json file to use that instead of 'flags'. See here for
+# more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
+#
+# You can get CMake to generate this file for you by adding:
+#   set( CMAKE_EXPORT_COMPILE_COMMANDS 1 )
+# to your CMakeLists.txt file.
+#
+# Most projects will NOT need to set this to anything; you can just change the
+# 'flags' list of compilation flags. Notice that YCM itself uses that approach.
+compilation_database_folder = os.path.abspath(os.path.dirname(__file__))
+
+if os.path.exists( compilation_database_folder ):
+  database = ycm_core.CompilationDatabase( compilation_database_folder )
+else:
+  database = None
+
+SOURCE_EXTENSIONS = [ '.cpp', '.cxx', '.cc', '.c', '.m', '.mm' ]
+
+def DirectoryOfThisScript():
+  return os.path.dirname( os.path.abspath( __file__ ) )
+
+
+def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
+  if not working_directory:
+    return list( flags )
+  new_flags = []
+  make_next_absolute = False
+  path_flags = [ '-isystem', '-I', '-iquote', '--sysroot=' ]
+  for flag in flags:
+    new_flag = flag
+
+    if make_next_absolute:
+      make_next_absolute = False
+      if not flag.startswith( '/' ):
+        new_flag = os.path.join( working_directory, flag )
+
+    for path_flag in path_flags:
+      if flag == path_flag:
+        make_next_absolute = True
+        break
+
+      if flag.startswith( path_flag ):
+        path = flag[ len( path_flag ): ]
+        new_flag = path_flag + os.path.join( working_directory, path )
+        break
+
+    if new_flag:
+      new_flags.append( new_flag )
+  return new_flags
+
+
+def IsHeaderFile( filename ):
+  extension = os.path.splitext( filename )[ 1 ]
+  return extension in [ '.h', '.hxx', '.hpp', '.hh' ]
+
+
+def GetCompilationInfoForFile( filename ):
+  # The compilation_commands.json file generated by CMake does not have entries
+  # for header files. So we do our best by asking the db for flags for a
+  # corresponding source file, if any. If one exists, the flags for that file
+  # should be good enough.
+  if IsHeaderFile( filename ):
+    basename = os.path.splitext( filename )[ 0 ]
+    for extension in SOURCE_EXTENSIONS:
+      replacement_file = basename + extension
+      if os.path.exists( replacement_file ):
+        compilation_info = database.GetCompilationInfoForFile(
+          replacement_file )
+        if compilation_info.compiler_flags_:
+          return compilation_info
+    return None
+  return database.GetCompilationInfoForFile( filename )
+
+
+def FlagsForFile( filename, **kwargs ):
+  if database:
+    # Bear in mind that compilation_info.compiler_flags_ does NOT return a
+    # python list, but a "list-like" StringVec object
+    compilation_info = GetCompilationInfoForFile( filename )
+    if not compilation_info:
+      return None
+
+    final_flags = MakeRelativePathsInFlagsAbsolute(
+      compilation_info.compiler_flags_,
+      compilation_info.compiler_working_dir_ )
+
+  else:
+    relative_to = DirectoryOfThisScript()
+    final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )
+
+  return {
+    'flags': final_flags,
+    'do_cache': True
+  }