Replace travis with github actions (#9641)

* Move outside of travis to Github actions

This will permit to have better integrated CI workflow than the previous
travis one.

6 files changed, 935 insertions, 0 deletions

diff --git a/util/ci/build.sh b/util/ci/build.sh
new file mode 100755
index 000000000..59069b00a
--- /dev/null
+++ b/util/ci/build.sh
@@ -0,0 +1,8 @@
+#! /bin/bash -eu
+
+mkdir cmakebuild
+cd cmakebuild
+cmake -DCMAKE_BUILD_TYPE=Debug \
+	-DRUN_IN_PLACE=TRUE -DENABLE_GETTEXT=TRUE \
+	-DBUILD_SERVER=TRUE ${CMAKE_FLAGS} ..
+make -j2
diff --git a/util/ci/clang-format-whitelist.txt b/util/ci/clang-format-whitelist.txt
new file mode 100644
index 000000000..3334257ae
--- /dev/null
+++ b/util/ci/clang-format-whitelist.txt
@@ -0,0 +1,500 @@
+src/activeobject.h
+src/ban.cpp
+src/camera.cpp
+src/camera.h
+src/chat.cpp
+src/chat.h
+src/chat_interface.h
+src/client/clientlauncher.cpp
+src/client/clientlauncher.h
+src/client/sound_openal.cpp
+src/client.cpp
+src/clientenvironment.cpp
+src/clientenvironment.h
+src/client/gameui.cpp
+src/client.h
+src/client/hud.cpp
+src/client/hud.h
+src/clientiface.cpp
+src/clientiface.h
+src/client/joystick_controller.cpp
+src/client/joystick_controller.h
+src/clientmap.cpp
+src/clientmap.h
+src/clientmedia.cpp
+src/clientmedia.h
+src/clientobject.cpp
+src/clientobject.h
+src/client/render/core.cpp
+src/client/renderingengine.cpp
+src/client/render/interlaced.cpp
+src/client/render/plain.cpp
+src/client/render/sidebyside.cpp
+src/client/render/stereo.cpp
+src/client/tile.cpp
+src/client/tile.h
+src/client/fontengine.h
+src/client/clientenvironment.cpp
+src/client/mapblock_mesh.cpp
+src/client/sound_openal.h
+src/client/clouds.cpp
+src/client/fontengine.cpp
+src/client/camera.h
+src/client/hud.cpp
+src/client/clientmap.cpp
+src/client/sound_openal.cpp
+src/client/minimap.h
+src/client/content_cao.cpp
+src/client/localplayer.h
+src/client/mapblock_mesh.h
+src/client/mesh.cpp
+src/client/sound.cpp
+src/client/guiscalingfilter.cpp
+src/client/content_cso.cpp
+src/client/gameui.cpp
+src/client/wieldmesh.cpp
+src/client/clientmedia.h
+src/client/game.cpp
+src/client/keys.h
+src/client/client.h
+src/client/shader.cpp
+src/client/clientmap.h
+src/client/inputhandler.h
+src/client/content_mapblock.h
+src/client/game.h
+src/client/mesh.h
+src/client/camera.cpp
+src/client/sky.h
+src/client/mesh_generator_thread.cpp
+src/client/guiscalingfilter.h
+src/client/clientobject.cpp
+src/client/tile.cpp
+src/client/hud.h
+src/client/inputhandler.cpp
+src/client/clientevent.h
+src/client/gameui.h
+src/client/content_cso.h
+src/client/sky.cpp
+src/client/localplayer.cpp
+src/client/content_mapblock.cpp
+src/client/clientobject.h
+src/client/filecache.cpp
+src/client/particles.h
+src/client/clientenvironment.h
+src/client/imagefilters.h
+src/client/renderingengine.cpp
+src/client/tile.h
+src/client/clientmedia.cpp
+src/client/event_manager.h
+src/client/joystick_controller.h
+src/client/clouds.h
+src/client/clientlauncher.h
+src/client/content_cao.h
+src/client/minimap.cpp
+src/client/sound.h
+src/client/keycode.cpp
+src/client/particles.cpp
+src/client/joystick_controller.cpp
+src/client/keycode.h
+src/client/wieldmesh.h
+src/client/filecache.h
+src/client/shader.h
+src/client/mesh_generator_thread.h
+src/client/renderingengine.h
+src/client/client.cpp
+src/client/imagefilters.cpp
+src/client/clientlauncher.cpp
+src/clouds.cpp
+src/clouds.h
+src/collision.cpp
+src/collision.h
+src/config.h
+src/content_cao.cpp
+src/content_cao.h
+src/content_cso.cpp
+src/content_cso.h
+src/content_mapblock.cpp
+src/content_mapblock.h
+src/content_mapnode.cpp
+src/content_nodemeta.cpp
+src/content_nodemeta.h
+src/convert_json.cpp
+src/convert_json.h
+src/craftdef.cpp
+src/craftdef.h
+src/database/database.cpp
+src/database/database-dummy.cpp
+src/database/database-files.cpp
+src/database/database-leveldb.cpp
+src/database/database-postgresql.cpp
+src/database/database-postgresql.h
+src/database/database-redis.cpp
+src/database/database-sqlite3.cpp
+src/database/database-sqlite3.h
+src/daynightratio.h
+src/debug.cpp
+src/debug.h
+src/defaultsettings.cpp
+src/emerge.cpp
+src/emerge.h
+src/environment.cpp
+src/exceptions.h
+src/face_position_cache.cpp
+src/face_position_cache.h
+src/filecache.cpp
+src/filesys.cpp
+src/filesys.h
+src/fontengine.cpp
+src/fontengine.h
+src/game.cpp
+src/gamedef.h
+src/game.h
+src/gettext.cpp
+src/gettext.h
+src/gui/guiAnimatedImage.cpp
+src/gui/guiAnimatedImage.h
+src/gui/guiBackgroundImage.cpp
+src/gui/guiBackgroundImage.h
+src/gui/guiBox.cpp
+src/gui/guiBox.h
+src/gui/guiButton.cpp
+src/gui/guiButton.h
+src/gui/guiButtonImage.cpp
+src/gui/guiButtonImage.h
+src/gui/guiButtonItemImage.cpp
+src/gui/guiButtonItemImage.h
+src/gui/guiChatConsole.cpp
+src/gui/guiChatConsole.h
+src/gui/guiConfirmRegistration.cpp
+src/gui/guiEditBoxWithScrollbar.cpp
+src/gui/guiEditBoxWithScrollbar.h
+src/gui/guiEngine.cpp
+src/gui/guiEngine.h
+src/gui/guiFormSpecMenu.cpp
+src/gui/guiFormSpecMenu.h
+src/gui/guiKeyChangeMenu.cpp
+src/gui/guiHyperText.cpp
+src/gui/guiHyperText.h
+src/gui/guiInventoryList.cpp
+src/gui/guiInventoryList.h
+src/gui/guiItemImage.cpp
+src/gui/guiItemImage.h
+src/gui/guiMainMenu.h
+src/gui/guiPasswordChange.cpp
+src/gui/guiPathSelectMenu.cpp
+src/gui/guiPathSelectMenu.h
+src/gui/guiScrollBar.cpp
+src/gui/guiSkin.cpp
+src/gui/guiSkin.h
+src/gui/guiTable.cpp
+src/gui/guiTable.h
+src/gui/guiVolumeChange.cpp
+src/gui/guiVolumeChange.h
+src/gui/intlGUIEditBox.cpp
+src/gui/intlGUIEditBox.h
+src/gui/mainmenumanager.h
+src/gui/modalMenu.h
+src/guiscalingfilter.cpp
+src/guiscalingfilter.h
+src/gui/StyleSpec.h
+src/gui/touchscreengui.cpp
+src/httpfetch.cpp
+src/hud.cpp
+src/hud.h
+src/imagefilters.cpp
+src/imagefilters.h
+src/inventory.cpp
+src/inventory.h
+src/inventorymanager.cpp
+src/inventorymanager.h
+src/irrlicht_changes/CGUITTFont.cpp
+src/irrlicht_changes/CGUITTFont.h
+src/irrlicht_changes/irrUString.h
+src/irrlicht_changes/static_text.cpp
+src/irrlicht_changes/static_text.h
+src/irrlichttypes.h
+src/itemdef.cpp
+src/itemdef.h
+src/itemstackmetadata.cpp
+src/keycode.cpp
+src/light.cpp
+src/localplayer.cpp
+src/log.cpp
+src/log.h
+src/main.cpp
+src/mapblock.cpp
+src/mapblock.h
+src/mapblock_mesh.cpp
+src/mapblock_mesh.h
+src/map.cpp
+src/mapgen/cavegen.cpp
+src/mapgen/cavegen.h
+src/mapgen/dungeongen.cpp
+src/mapgen/dungeongen.h
+src/mapgen/mapgen.cpp
+src/mapgen/mapgen.h
+src/mapgen/mapgen_carpathian.cpp
+src/mapgen/mapgen_carpathian.h
+src/mapgen/mapgen_flat.cpp
+src/mapgen/mapgen_flat.h
+src/mapgen/mapgen_fractal.cpp
+src/mapgen/mapgen_fractal.h
+src/mapgen/mapgen_singlenode.cpp
+src/mapgen/mapgen_singlenode.h
+src/mapgen/mapgen_v5.cpp
+src/mapgen/mapgen_v5.h
+src/mapgen/mapgen_v6.cpp
+src/mapgen/mapgen_v6.h
+src/mapgen/mapgen_v7.cpp
+src/mapgen/mapgen_v7.h
+src/mapgen/mapgen_valleys.cpp
+src/mapgen/mapgen_valleys.h
+src/mapgen/mg_biome.cpp
+src/mapgen/mg_biome.h
+src/mapgen/mg_decoration.cpp
+src/mapgen/mg_decoration.h
+src/mapgen/mg_ore.cpp
+src/mapgen/mg_ore.h
+src/mapgen/mg_schematic.cpp
+src/mapgen/mg_schematic.h
+src/mapgen/treegen.cpp
+src/mapgen/treegen.h
+src/map.h
+src/mapnode.cpp
+src/mapnode.h
+src/mapsector.cpp
+src/mapsector.h
+src/map_settings_manager.cpp
+src/map_settings_manager.h
+src/mesh.cpp
+src/mesh_generator_thread.cpp
+src/mesh.h
+src/metadata.h
+src/minimap.cpp
+src/minimap.h
+src/mods.cpp
+src/mods.h
+src/network/address.cpp
+src/network/clientopcodes.cpp
+src/network/clientopcodes.h
+src/network/clientpackethandler.cpp
+src/network/connection.cpp
+src/network/connection.h
+src/network/connectionthreads.cpp
+src/network/networkpacket.cpp
+src/network/networkprotocol.h
+src/network/serveropcodes.cpp
+src/network/serveropcodes.h
+src/network/serverpackethandler.cpp
+src/nodedef.cpp
+src/nodedef.h
+src/nodemetadata.cpp
+src/nodemetadata.h
+src/nodetimer.cpp
+src/nodetimer.h
+src/noise.cpp
+src/noise.h
+src/objdef.cpp
+src/objdef.h
+src/object_properties.cpp
+src/object_properties.h
+src/particles.cpp
+src/particles.h
+src/pathfinder.cpp
+src/pathfinder.h
+src/player.cpp
+src/player.h
+src/porting_android.cpp
+src/porting_android.h
+src/porting.cpp
+src/porting.h
+src/profiler.h
+src/raycast.cpp
+src/raycast.h
+src/reflowscan.cpp
+src/reflowscan.h
+src/remoteplayer.cpp
+src/rollback.cpp
+src/rollback.h
+src/rollback_interface.cpp
+src/rollback_interface.h
+src/script/common/c_content.cpp
+src/script/common/c_content.h
+src/script/common/c_converter.cpp
+src/script/common/c_converter.h
+src/script/common/c_internal.cpp
+src/script/common/c_internal.h
+src/script/common/c_types.cpp
+src/script/common/c_types.h
+src/script/cpp_api/s_async.cpp
+src/script/cpp_api/s_async.h
+src/script/cpp_api/s_base.cpp
+src/script/cpp_api/s_base.h
+src/script/cpp_api/s_client.cpp
+src/script/cpp_api/s_entity.cpp
+src/script/cpp_api/s_entity.h
+src/script/cpp_api/s_env.cpp
+src/script/cpp_api/s_env.h
+src/script/cpp_api/s_internal.h
+src/script/cpp_api/s_inventory.cpp
+src/script/cpp_api/s_inventory.h
+src/script/cpp_api/s_item.cpp
+src/script/cpp_api/s_item.h
+src/script/cpp_api/s_mainmenu.h
+src/script/cpp_api/s_node.cpp
+src/script/cpp_api/s_node.h
+src/script/cpp_api/s_nodemeta.cpp
+src/script/cpp_api/s_nodemeta.h
+src/script/cpp_api/s_player.cpp
+src/script/cpp_api/s_player.h
+src/script/cpp_api/s_security.cpp
+src/script/cpp_api/s_security.h
+src/script/cpp_api/s_server.cpp
+src/script/cpp_api/s_server.h
+src/script/lua_api/l_areastore.cpp
+src/script/lua_api/l_base.cpp
+src/script/lua_api/l_base.h
+src/script/lua_api/l_client.cpp
+src/script/lua_api/l_craft.cpp
+src/script/lua_api/l_craft.h
+src/script/lua_api/l_env.cpp
+src/script/lua_api/l_env.h
+src/script/lua_api/l_http.cpp
+src/script/lua_api/l_http.h
+src/script/lua_api/l_internal.h
+src/script/lua_api/l_inventory.cpp
+src/script/lua_api/l_inventory.h
+src/script/lua_api/l_item.cpp
+src/script/lua_api/l_item.h
+src/script/lua_api/l_itemstackmeta.cpp
+src/script/lua_api/l_itemstackmeta.h
+src/script/lua_api/l_localplayer.cpp
+src/script/lua_api/l_mainmenu.cpp
+src/script/lua_api/l_mainmenu.h
+src/script/lua_api/l_mapgen.cpp
+src/script/lua_api/l_mapgen.h
+src/script/lua_api/l_metadata.cpp
+src/script/lua_api/l_minimap.cpp
+src/script/lua_api/l_nodemeta.cpp
+src/script/lua_api/l_nodemeta.h
+src/script/lua_api/l_nodetimer.cpp
+src/script/lua_api/l_noise.cpp
+src/script/lua_api/l_object.cpp
+src/script/lua_api/l_object.h
+src/script/lua_api/l_particles.cpp
+src/script/lua_api/l_particles.h
+src/script/lua_api/l_particles_local.cpp
+src/script/lua_api/l_rollback.cpp
+src/script/lua_api/l_rollback.h
+src/script/lua_api/l_server.cpp
+src/script/lua_api/l_settings.cpp
+src/script/lua_api/l_sound.cpp
+src/script/lua_api/l_storage.cpp
+src/script/lua_api/l_util.cpp
+src/script/lua_api/l_vmanip.cpp
+src/script/scripting_client.cpp
+src/script/scripting_client.h
+src/script/scripting_mainmenu.cpp
+src/script/scripting_mainmenu.h
+src/script/scripting_server.cpp
+src/script/scripting_server.h
+src/serialization.cpp
+src/serialization.h
+src/server.cpp
+src/serverenvironment.cpp
+src/serverenvironment.h
+src/server.h
+src/serverlist.cpp
+src/serverlist.h
+src/server/luaentity_sao.cpp
+src/server/player_sao.cpp
+src/server/serveractiveobject.cpp
+src/server/serveractiveobject.h
+src/settings.cpp
+src/settings.h
+src/settings_translation_file.cpp
+src/shader.cpp
+src/shader.h
+src/sky.cpp
+src/sound.cpp
+src/staticobject.cpp
+src/staticobject.h
+src/subgame.cpp
+src/subgame.h
+src/terminal_chat_console.cpp
+src/terminal_chat_console.h
+src/texture_override.cpp
+src/threading/atomic.h
+src/threading/event.cpp
+src/threading/mutex_auto_lock.h
+src/threading/mutex.cpp
+src/threading/mutex.h
+src/threading/semaphore.cpp
+src/threading/thread.cpp
+src/threading/thread.h
+src/threads.h
+src/tileanimation.cpp
+src/tileanimation.h
+src/tool.cpp
+src/tool.h
+src/translation.cpp
+src/unittest/test_areastore.cpp
+src/unittest/test_collision.cpp
+src/unittest/test_compression.cpp
+src/unittest/test_connection.cpp
+src/unittest/test.cpp
+src/unittest/test_filepath.cpp
+src/unittest/test.h
+src/unittest/test_inventory.cpp
+src/unittest/test_keycode.cpp
+src/unittest/test_map_settings_manager.cpp
+src/unittest/test_noderesolver.cpp
+src/unittest/test_noise.cpp
+src/unittest/test_random.cpp
+src/unittest/test_schematic.cpp
+src/unittest/test_serialization.cpp
+src/unittest/test_settings.cpp
+src/unittest/test_socket.cpp
+src/unittest/test_threading.cpp
+src/unittest/test_utilities.cpp
+src/unittest/test_voxelalgorithms.cpp
+src/unittest/test_voxelmanipulator.cpp
+src/util/areastore.cpp
+src/util/areastore.h
+src/util/auth.cpp
+src/util/auth.h
+src/util/base64.cpp
+src/util/base64.h
+src/util/basic_macros.h
+src/util/container.h
+src/util/directiontables.cpp
+src/util/directiontables.h
+src/util/enriched_string.cpp
+src/util/enriched_string.h
+src/util/md32_common.h
+src/util/numeric.cpp
+src/util/numeric.h
+src/util/pointedthing.cpp
+src/util/pointedthing.h
+src/util/pointer.h
+src/util/quicktune.h
+src/util/quicktune_shortcutter.h
+src/util/quicktune.cpp
+src/util/serialize.cpp
+src/util/serialize.h
+src/util/sha1.cpp
+src/util/srp.cpp
+src/util/srp.h
+src/util/strfnd.h
+src/util/string.cpp
+src/util/string.h
+src/util/thread.h
+src/util/timetaker.cpp
+src/util/timetaker.h
+src/version.cpp
+src/version.h
+src/voxelalgorithms.cpp
+src/voxelalgorithms.h
+src/voxel.cpp
+src/voxel.h
+src/wieldmesh.cpp
diff --git a/util/ci/clang-tidy.sh b/util/ci/clang-tidy.sh
new file mode 100755
index 000000000..d048f54ee
--- /dev/null
+++ b/util/ci/clang-tidy.sh
@@ -0,0 +1,18 @@
+#! /bin/bash -eu
+
+mkdir -p cmakebuild
+cd cmakebuild
+cmake -DCMAKE_BUILD_TYPE=Debug \
+	-DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
+	-DRUN_IN_PLACE=TRUE \
+	-DENABLE_GETTEXT=TRUE \
+	-DENABLE_SOUND=FALSE \
+	-DBUILD_SERVER=TRUE ..
+make GenerateVersion
+
+cd ..
+
+./util/ci/run-clang-tidy.py \
+	-clang-tidy-binary=clang-tidy-9 -p cmakebuild \
+	-quiet -config="$(cat .clang-tidy)" \
+	'src/.*'
diff --git a/util/ci/common.sh b/util/ci/common.sh
new file mode 100644
index 000000000..5a4f78457
--- /dev/null
+++ b/util/ci/common.sh
@@ -0,0 +1,45 @@
+#!/bin/bash -e
+
+set_linux_compiler_env() {
+	if [[ "${COMPILER}" == "gcc-6" ]]; then
+		export CC=gcc-6
+		export CXX=g++-6
+	elif [[ "${COMPILER}" == "gcc-8" ]]; then
+		export CC=gcc-8
+		export CXX=g++-8
+	elif [[ "${COMPILER}" == "clang-3.9" ]]; then
+		export CC=clang-3.9
+		export CXX=clang++-3.9
+	elif [[ "${COMPILER}" == "clang-9" ]]; then
+		export CC=clang-9
+		export CXX=clang++-9
+	fi
+}
+
+# Linux build only
+install_linux_deps() {
+	local pkgs=(libirrlicht-dev cmake libbz2-dev libpng-dev \
+		libjpeg-dev libxxf86vm-dev libgl1-mesa-dev libsqlite3-dev \
+		libhiredis-dev libogg-dev libgmp-dev libvorbis-dev libopenal-dev \
+		gettext libpq-dev postgresql-server-dev-all libleveldb-dev \
+		libcurl4-openssl-dev)
+	# for better coverage, build some jobs with luajit
+	if [ -n "$WITH_LUAJIT" ]; then
+		pkgs+=(libluajit-5.1-dev)
+	fi
+
+	sudo apt-get update
+	sudo apt-get install -y --no-install-recommends ${pkgs[@]}
+}
+
+# Mac OSX build only
+install_macosx_deps() {
+	brew update
+	brew install freetype gettext hiredis irrlicht leveldb libogg libvorbis luajit
+	if brew ls | grep -q jpeg; then
+		brew upgrade jpeg
+	else
+		brew install jpeg
+	fi
+	#brew upgrade postgresql
+}
diff --git a/util/ci/lint.sh b/util/ci/lint.sh
new file mode 100644
index 000000000..395445ca7
--- /dev/null
+++ b/util/ci/lint.sh
@@ -0,0 +1,43 @@
+#! /bin/bash
+function perform_lint() {
+	echo "Performing LINT..."
+	if [ -z "${CLANG_FORMAT}" ]; then
+		CLANG_FORMAT=clang-format
+	fi
+	echo "LINT: Using binary $CLANG_FORMAT"
+	CLANG_FORMAT_WHITELIST="util/ci/clang-format-whitelist.txt"
+
+	files_to_lint="$(find src/ -name '*.cpp' -or -name '*.h')"
+
+	local errorcount=0
+	local fail=0
+	for f in ${files_to_lint}; do
+		d=$(diff -u "$f" <(${CLANG_FORMAT} "$f") || true)
+
+		if ! [ -z "$d" ]; then
+			whitelisted=$(awk '$1 == "'$f'" { print 1 }' "$CLANG_FORMAT_WHITELIST")
+
+			# If file is not whitelisted, mark a failure
+			if [ -z "${whitelisted}" ]; then
+				errorcount=$((errorcount+1))
+
+				printf "The file %s is not compliant with the coding style" "$f"
+				if [ ${errorcount} -gt 50 ]; then
+					printf "\nToo many errors encountered previously, this diff is hidden.\n"
+				else
+					printf ":\n%s\n" "$d"
+				fi
+
+				fail=1
+			fi
+		fi
+	done
+
+	if [ "$fail" = 1 ]; then
+		echo "LINT reports failure."
+		exit 1
+	fi
+
+	echo "LINT OK"
+}
+
diff --git a/util/ci/run-clang-tidy.py b/util/ci/run-clang-tidy.py
new file mode 100755
index 000000000..6ad0ff24f
--- /dev/null
+++ b/util/ci/run-clang-tidy.py
@@ -0,0 +1,321 @@
+#!/usr/bin/env python
+#
+#===- run-clang-tidy.py - Parallel clang-tidy runner ---------*- python -*--===#
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+#===------------------------------------------------------------------------===#
+# FIXME: Integrate with clang-tidy-diff.py
+
+"""
+Parallel clang-tidy runner
+==========================
+
+Runs clang-tidy over all files in a compilation database. Requires clang-tidy
+and clang-apply-replacements in $PATH.
+
+Example invocations.
+- Run clang-tidy on all files in the current working directory with a default
+  set of checks and show warnings in the cpp files and all project headers.
+    run-clang-tidy.py $PWD
+
+- Fix all header guards.
+    run-clang-tidy.py -fix -checks=-*,llvm-header-guard
+
+- Fix all header guards included from clang-tidy and header guards
+  for clang-tidy headers.
+    run-clang-tidy.py -fix -checks=-*,llvm-header-guard extra/clang-tidy \
+                      -header-filter=extra/clang-tidy
+
+Compilation database setup:
+http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
+"""
+
+from __future__ import print_function
+
+import argparse
+import glob
+import json
+import multiprocessing
+import os
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+import threading
+import traceback
+
+try:
+  import yaml
+except ImportError:
+  yaml = None
+
+is_py2 = sys.version[0] == '2'
+
+if is_py2:
+    import Queue as queue
+else:
+    import queue as queue
+
+def find_compilation_database(path):
+  """Adjusts the directory until a compilation database is found."""
+  result = './'
+  while not os.path.isfile(os.path.join(result, path)):
+    if os.path.realpath(result) == '/':
+      print('Error: could not find compilation database.')
+      sys.exit(1)
+    result += '../'
+  return os.path.realpath(result)
+
+
+def make_absolute(f, directory):
+  if os.path.isabs(f):
+    return f
+  return os.path.normpath(os.path.join(directory, f))
+
+
+def get_tidy_invocation(f, clang_tidy_binary, checks, tmpdir, build_path,
+                        header_filter, extra_arg, extra_arg_before, quiet,
+                        config):
+  """Gets a command line for clang-tidy."""
+  start = [clang_tidy_binary]
+  if header_filter is not None:
+    start.append('-header-filter=' + header_filter)
+  if checks:
+    start.append('-checks=' + checks)
+  if tmpdir is not None:
+    start.append('-export-fixes')
+    # Get a temporary file. We immediately close the handle so clang-tidy can
+    # overwrite it.
+    (handle, name) = tempfile.mkstemp(suffix='.yaml', dir=tmpdir)
+    os.close(handle)
+    start.append(name)
+  for arg in extra_arg:
+      start.append('-extra-arg=%s' % arg)
+  for arg in extra_arg_before:
+      start.append('-extra-arg-before=%s' % arg)
+  start.append('-p=' + build_path)
+  if quiet:
+      start.append('-quiet')
+  if config:
+      start.append('-config=' + config)
+  start.append(f)
+  return start
+
+
+def merge_replacement_files(tmpdir, mergefile):
+  """Merge all replacement files in a directory into a single file"""
+  # The fixes suggested by clang-tidy >= 4.0.0 are given under
+  # the top level key 'Diagnostics' in the output yaml files
+  mergekey="Diagnostics"
+  merged=[]
+  for replacefile in glob.iglob(os.path.join(tmpdir, '*.yaml')):
+    content = yaml.safe_load(open(replacefile, 'r'))
+    if not content:
+      continue # Skip empty files.
+    merged.extend(content.get(mergekey, []))
+
+  if merged:
+    # MainSourceFile: The key is required by the definition inside
+    # include/clang/Tooling/ReplacementsYaml.h, but the value
+    # is actually never used inside clang-apply-replacements,
+    # so we set it to '' here.
+    output = { 'MainSourceFile': '', mergekey: merged }
+    with open(mergefile, 'w') as out:
+      yaml.safe_dump(output, out)
+  else:
+    # Empty the file:
+    open(mergefile, 'w').close()
+
+
+def check_clang_apply_replacements_binary(args):
+  """Checks if invoking supplied clang-apply-replacements binary works."""
+  try:
+    subprocess.check_call([args.clang_apply_replacements_binary, '--version'])
+  except:
+    print('Unable to run clang-apply-replacements. Is clang-apply-replacements '
+          'binary correctly specified?', file=sys.stderr)
+    traceback.print_exc()
+    sys.exit(1)
+
+
+def apply_fixes(args, tmpdir):
+  """Calls clang-apply-fixes on a given directory."""
+  invocation = [args.clang_apply_replacements_binary]
+  if args.format:
+    invocation.append('-format')
+  if args.style:
+    invocation.append('-style=' + args.style)
+  invocation.append(tmpdir)
+  subprocess.call(invocation)
+
+
+def run_tidy(args, tmpdir, build_path, queue, lock, failed_files):
+  """Takes filenames out of queue and runs clang-tidy on them."""
+  while True:
+    name = queue.get()
+    invocation = get_tidy_invocation(name, args.clang_tidy_binary, args.checks,
+                                     tmpdir, build_path, args.header_filter,
+                                     args.extra_arg, args.extra_arg_before,
+                                     args.quiet, args.config)
+
+    proc = subprocess.Popen(invocation)
+    proc.wait()
+    if proc.returncode != 0:
+      failed_files.append(name)
+    queue.task_done()
+
+
+def main():
+  parser = argparse.ArgumentParser(description='Runs clang-tidy over all files '
+                                   'in a compilation database. Requires '
+                                   'clang-tidy and clang-apply-replacements in '
+                                   '$PATH.')
+  parser.add_argument('-clang-tidy-binary', metavar='PATH',
+                      default='clang-tidy',
+                      help='path to clang-tidy binary')
+  parser.add_argument('-clang-apply-replacements-binary', metavar='PATH',
+                      default='clang-apply-replacements',
+                      help='path to clang-apply-replacements binary')
+  parser.add_argument('-checks', default=None,
+                      help='checks filter, when not specified, use clang-tidy '
+                      'default')
+  parser.add_argument('-config', default=None,
+                      help='Specifies a configuration in YAML/JSON format: '
+                      '  -config="{Checks: \'*\', '
+                      '                       CheckOptions: [{key: x, '
+                      '                                       value: y}]}" '
+                      'When the value is empty, clang-tidy will '
+                      'attempt to find a file named .clang-tidy for '
+                      'each source file in its parent directories.')
+  parser.add_argument('-header-filter', default=None,
+                      help='regular expression matching the names of the '
+                      'headers to output diagnostics from. Diagnostics from '
+                      'the main file of each translation unit are always '
+                      'displayed.')
+  if yaml:
+    parser.add_argument('-export-fixes', metavar='filename', dest='export_fixes',
+                        help='Create a yaml file to store suggested fixes in, '
+                        'which can be applied with clang-apply-replacements.')
+  parser.add_argument('-j', type=int, default=0,
+                      help='number of tidy instances to be run in parallel.')
+  parser.add_argument('files', nargs='*', default=['.*'],
+                      help='files to be processed (regex on path)')
+  parser.add_argument('-fix', action='store_true', help='apply fix-its')
+  parser.add_argument('-format', action='store_true', help='Reformat code '
+                      'after applying fixes')
+  parser.add_argument('-style', default='file', help='The style of reformat '
+                      'code after applying fixes')
+  parser.add_argument('-p', dest='build_path',
+                      help='Path used to read a compile command database.')
+  parser.add_argument('-extra-arg', dest='extra_arg',
+                      action='append', default=[],
+                      help='Additional argument to append to the compiler '
+                      'command line.')
+  parser.add_argument('-extra-arg-before', dest='extra_arg_before',
+                      action='append', default=[],
+                      help='Additional argument to prepend to the compiler '
+                      'command line.')
+  parser.add_argument('-quiet', action='store_true',
+                      help='Run clang-tidy in quiet mode')
+  args = parser.parse_args()
+
+  db_path = 'compile_commands.json'
+
+  if args.build_path is not None:
+    build_path = args.build_path
+  else:
+    # Find our database
+    build_path = find_compilation_database(db_path)
+
+  try:
+    invocation = [args.clang_tidy_binary, '-list-checks']
+    invocation.append('-p=' + build_path)
+    if args.checks:
+      invocation.append('-checks=' + args.checks)
+    invocation.append('-')
+    if args.quiet:
+      # Even with -quiet we still want to check if we can call clang-tidy.
+      with open(os.devnull, 'w') as dev_null:
+        subprocess.check_call(invocation, stdout=dev_null)
+    else:
+      subprocess.check_call(invocation)
+  except:
+    print("Unable to run clang-tidy.", file=sys.stderr)
+    sys.exit(1)
+
+  # Load the database and extract all files.
+  database = json.load(open(os.path.join(build_path, db_path)))
+  files = [make_absolute(entry['file'], entry['directory'])
+           for entry in database]
+
+  max_task = args.j
+  if max_task == 0:
+    max_task = multiprocessing.cpu_count()
+
+  tmpdir = None
+  if args.fix or (yaml and args.export_fixes):
+    check_clang_apply_replacements_binary(args)
+    tmpdir = tempfile.mkdtemp()
+
+  # Build up a big regexy filter from all command line arguments.
+  file_name_re = re.compile('|'.join(args.files))
+
+  return_code = 0
+  try:
+    # Spin up a bunch of tidy-launching threads.
+    task_queue = queue.Queue(max_task)
+    # List of files with a non-zero return code.
+    failed_files = []
+    lock = threading.Lock()
+    for _ in range(max_task):
+      t = threading.Thread(target=run_tidy,
+                           args=(args, tmpdir, build_path, task_queue, lock, failed_files))
+      t.daemon = True
+      t.start()
+
+    # Fill the queue with files.
+    for name in files:
+      if file_name_re.search(name):
+        task_queue.put(name)
+
+    # Wait for all threads to be done.
+    task_queue.join()
+    if len(failed_files):
+      return_code = 1
+
+  except KeyboardInterrupt:
+    # This is a sad hack. Unfortunately subprocess goes
+    # bonkers with ctrl-c and we start forking merrily.
+    print('\nCtrl-C detected, goodbye.')
+    if tmpdir:
+      shutil.rmtree(tmpdir)
+    os.kill(0, 9)
+
+  if yaml and args.export_fixes:
+    print('Writing fixes to ' + args.export_fixes + ' ...')
+    try:
+      merge_replacement_files(tmpdir, args.export_fixes)
+    except:
+      print('Error exporting fixes.\n', file=sys.stderr)
+      traceback.print_exc()
+      return_code=1
+
+  if args.fix:
+    print('Applying fixes ...')
+    try:
+      apply_fixes(args, tmpdir)
+    except:
+      print('Error applying fixes.\n', file=sys.stderr)
+      traceback.print_exc()
+      return_code=1
+
+  if tmpdir:
+    shutil.rmtree(tmpdir)
+  sys.exit(return_code)
+
+if __name__ == '__main__':
+  main()