Enable ycmd for project

.ycm_extra_conf.py

@@ -0,0 +1,130 @@
+'''This file provides editor completions while working on DFHack using ycmd:
+https://github.com/Valloric/ycmd
+'''
+
+# pylint: disable=import-error,invalid-name,missing-docstring,unused-argument
+
+import os
+import ycm_core
+
+def DirectoryOfThisScript():
+    return os.path.dirname(os.path.abspath(__file__))
+
+# We need to tell YouCompleteMe how to compile this project. We do this using
+# clang's "Compilation Database" system, which essentially just dumps a big
+# json file into the build folder.
+# More details: http://clang.llvm.org/docs/JSONCompilationDatabase.html
+#
+# We don't use clang, but luckily CMake supports generating a database on its
+# own, using:
+#     set( CMAKE_EXPORT_COMPILE_COMMANDS 1 )
+
+for potential_build_folder in ['build', 'build-osx']:
+    if os.path.exists(DirectoryOfThisScript() + os.path.sep + potential_build_folder
+                      + os.path.sep + 'compile_commands.json'):
+        database = ycm_core.CompilationDatabase(potential_build_folder)
+        break
+else:
+    raise RuntimeError("Can't find dfhack build folder: not one of build, build-osx")
+
+
+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']
+
+
+SOURCE_EXTENSIONS = ['.cpp', '.cxx', '.cc', '.c', '.m', '.mm']
+
+def PotentialAlternatives(header):
+    dirname, filename = os.path.split(header)
+    basename, _ = os.path.splitext(filename)
+
+    source_dirs = [dirname]
+
+    if dirname.endswith(os.path.sep + 'include'):
+        # if we're in a folder 'include', also look in its parent
+        parent = os.path.abspath(os.path.join(dirname, os.path.pardir))
+        source_dirs.append(parent)
+        # and ../src (used by lua dependency)
+        source_dirs.append(os.path.join(parent, 'src'))
+
+    include_idx = dirname.rfind(os.path.sep + 'include' + os.path.sep)
+    if include_idx != -1:
+        # we're in a subfolder of a parent '/include/'
+        # .../include/subdir/path
+        # look in .../subdir/path
+        source_dirs.append(
+            dirname[:include_idx] +
+            os.path.sep +
+            dirname[include_idx + len('include') + 2*len(os.path.sep):]
+        )
+
+    for source_dir in source_dirs:
+        for ext in SOURCE_EXTENSIONS:
+            yield source_dir + os.path.sep + basename + ext
+
+
+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):
+        for alternative in PotentialAlternatives(filename):
+            if os.path.exists(alternative):
+                compilation_info = database.GetCompilationInfoForFile(
+                    alternative
+                )
+
+                if compilation_info.compiler_flags_:
+                    return compilation_info
+        return None
+    else:
+        return database.GetCompilationInfoForFile(filename)
+
+
+def FlagsForFile(filename, **kwargs):
+    # 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_
+    )
+
+    return {
+        'flags': final_flags,
+        'do_cache': True
+    }

CMakeLists.txt

@@ -91,6 +91,9 @@ ${dfhack_SOURCE_DIR}/CMake/Modules
 ${CMAKE_MODULE_PATH}
 )
 
+# generates compile_commands.json, used for autocompletion by some editors
+SET(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
 # mixing the build system with the source code is ugly and stupid. enforce the opposite :)
 if("${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_BINARY_DIR}")
    message(FATAL_ERROR "In-source builds are not allowed.")