fix(ycm): Use compilation db for all possible files

This is basically a major rewrite of the .ycm_extra_conf.py file that
ycm uses to determine what compile commands it should use for a file.
But the basic purpose is for it to use the generated flags in
build/compile_commands.json that is generated by cmake for as many files
as possible.

Before it always used the hardcoded default flags which would not always
work for all files.

Now it gets the proper flags for all files I tested.
In the src and tests folder the flags are already generated by cmake
In the include folder it tries to use the flags of the corresponding
source files in the src folder

.ycm_extra_conf.py

@@ -1,40 +1,30 @@
-# Here's the license text for this file:
-#
-# This is free and unencumbered software released into the public domain.
-#
-# Anyone is free to copy, modify, publish, use, compile, sell, or
-# distribute this software, either in source code form or as a compiled
-# binary, for any purpose, commercial or non-commercial, and by any
-# means.
-#
-# In jurisdictions that recognize copyright laws, the author or authors
-# of this software dedicate any and all copyright interest in the
-# software to the public domain. We make this dedication for the benefit
-# of the public at large and to the detriment of our heirs and
-# successors. We intend this dedication to be an overt act of
-# relinquishment in perpetuity of all present and future rights to this
-# software under copyright law.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
-# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
-# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
-# OTHER DEALINGS IN THE SOFTWARE.
-#
-# For more information, please refer to <http://unlicense.org/>
-
 import os
 import ycm_core
 
+# Default flags
 flags = [
     '-std=c++14',
     '-Wall',
     '-Wextra',
+
+    # Relative paths are corrected by MakeRelativePathsInFlagsAbsolute
+    '-Isrc',
+    '-Iinclude',
+    '-Ilib/concurrentqueue/include',
+    '-Ilib/i3ipcpp/include',
+    '-Ilib/xpp/include',
+    '-Itests',
+
+    '-I/usr/include',
+    '-I/usr/include/freetype2',
     ]
 
-compilation_database_folder = ''
+# Base directory of the project, parent directory of all source files
+project_dir = os.path.dirname(os.path.abspath(__file__))
+
+# This assumes that everyone coding for this project builds inside the 'build'
+# directory
+compilation_database_folder = project_dir + "/build"
 
 if os.path.exists(compilation_database_folder):
   database = ycm_core.CompilationDatabase(compilation_database_folder)
@@ -43,18 +33,8 @@ else:
 
 SOURCE_EXTENSIONS = ['.cpp', '.cxx', '.cc', '.c', '.m', '.mm']
 
-def DirectoryOfThisScript():
+# Converts all relative paths in the given flag list to absolute paths with
-  return os.path.dirname( os.path.abspath( __file__ ) )
+# working_directory as the base directory
-
-flags.append('-I'+ DirectoryOfThisScript() +'/src')
-flags.append('-I'+ DirectoryOfThisScript() +'/include')
-flags.append('-I'+ DirectoryOfThisScript() +'/lib/concurrentqueue/include')
-flags.append('-I'+ DirectoryOfThisScript() +'/lib/i3ipcpp/include')
-flags.append('-I'+ DirectoryOfThisScript() +'/lib/xpp/include')
-flags.append('-I'+ DirectoryOfThisScript() +'/tests')
-flags.append('-I/usr/include')
-flags.append('-I/usr/include/freetype2')
-
 def MakeRelativePathsInFlagsAbsolute(flags, working_directory):
   if not working_directory:
     return list(flags)
@@ -85,50 +65,62 @@ def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):
 
 def IsHeaderFile(filename):
   extension = os.path.splitext(filename)[1]
-  return extension in [ '.h', '.hxx', '.hpp', '.hh' ]
+  return extension in ['.h', '.hxx', '.hpp', '.hh', ".inl"]
 
+# Tries to query the compilation database for flags
+# For header files it tries to use the flags for a corresponding source file
 def GetCompilationInfoForFile(filename):
+  if not database:
+    return None
+
   # 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
+  # for header files. We try to use the compile flags used for the corresponding
-  # corresponding source file, if any. If one exists, the flags for that file
+  # source file.
-  # should be good enough.
+  #
+  # For this try to replace the file extension with an extension that
+  # corresponds to a source and we also try to replace the 'include' folder in
+  # the path with 'src'
   if IsHeaderFile(filename) :
     basename = os.path.splitext(filename)[0]
+
+    # Absolute path of the include and source directories
+    include_dir = project_dir + "/include"
+    src_dir = project_dir + "/src"
+
+    # Absolute path without file extension, with the 'include' folder replaced
+    # with 'src' in the path
+    src_basename = None
+    # If the header file is inside the include dir, try to search in the src dir
+    if basename.startswith(include_dir):
+      # file path relative to include dir
+      rel_path_include = os.path.relpath(basename, include_dir)
+      src_basename = os.path.join(src_dir, rel_path_include)
+
     for extension in SOURCE_EXTENSIONS:
-      replacement_file = basename + extension
+      # A list of all possible replacement files to be searched
+      replacement_files = [basename + extension]
+
+      if src_basename:
+        replacement_files.append(src_basename + extension)
+
+      for replacement_file in replacement_files:
         if os.path.exists(replacement_file):
-        compilation_info = database.GetCompilationInfoForFile(
+          comp_info = database.GetCompilationInfoForFile(replacement_file)
-          replacement_file )
+          if comp_info.compiler_flags_:
-        if compilation_info.compiler_flags_:
+            return comp_info
-          return compilation_info
-    return None
   return database.GetCompilationInfoForFile(filename)
 
-
 def FlagsForFile(filename, **kwargs):
-  # if database:
+  compilation_info = GetCompilationInfoForFile(filename)
-  #   # Bear in mind that compilation_info.compiler_flags_ does NOT return a
+  if compilation_info and compilation_info.compiler_flags_:
-  #   # python list, but a "list-like" StringVec object
+    # Bear in mind that compilation_info.compiler_flags_ does NOT return a
-  #   compilation_info = GetCompilationInfoForFile( filename )
+    # python list, but a "list-like" StringVec object
-  #   if not compilation_info:
+    final_flags = MakeRelativePathsInFlagsAbsolute(
-  #     return None
+        compilation_info.compiler_flags_,
-  #
+        compilation_info.compiler_working_dir_)
-  #   final_flags = MakeRelativePathsInFlagsAbsolute(
+  else:
-  #     compilation_info.compiler_flags_,
+    # We use default flags if GetCompilationInfoForFile can't find any flags
-  #     compilation_info.compiler_working_dir_ )
+    relative_to = project_dir
-  #
-  #   # NOTE: This is just for YouCompleteMe; it's highly likely that your project
-  #   # does NOT need to remove the stdlib flag. DO NOT USE THIS IN YOUR
-  #   # ycm_extra_conf IF YOU'RE NOT 100% SURE YOU NEED IT.
-  #   try:
-  #     final_flags.remove( '-stdlib=libc++' )
-  #   except ValueError:
-  #     pass
-  # else:
-  relative_to = DirectoryOfThisScript()
     final_flags = MakeRelativePathsInFlagsAbsolute(flags, relative_to)
 
-  return {
+  return {'flags': final_flags, 'do_cache': True}
-    'flags': final_flags,
-    'do_cache': True
-  }