.ycm_extra_conf.py

import os
import ycm_core


def DirectoryOfThisScript():
    return os.path.dirname(os.path.abspath(__file__))


flags = [
    '-std=c++17',
    '-Wall',
    '-Wextra',
    '-Werror',
    '-Wno-unused-parameter',
    '-fexceptions',
    '-ferror-limit=0',
    '-x',
    'c++',
    '-I' + DirectoryOfThisScript(),
]

compilation_database_folder = DirectoryOfThisScript() + "/build"

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 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)


# This is the entry point; this function is called by ycmd to produce flags for
# a file.
def FlagsForFile(filename, **kwargs):
    default_flags = {
        'flags': flags,
        'include_paths_relative_to_dir': DirectoryOfThisScript()
    }
    if not database:
        return default_flags

    compilation_info = GetCompilationInfoForFile(filename)
    if not compilation_info:
        return default_flags

    # Bear in mind that compilation_info.compiler_flags_ does NOT return a
    # python list, but a "list-like" StringVec object.
    return {
        'flags': list(compilation_info.compiler_flags_),
        'include_paths_relative_to_dir': compilation_info.compiler_working_dir_
    }