WIP: Feature/#353 add clang tidy to the mix

These are the changes introduced by using clang-tidy.

All in all, we have done a decent job. Congrats!

Please comment on anything that you find strange, worthy to discuss, …

cmake/execute_clang_tidy.cmake

+#------------------------------------------------------------------------------
+# Project Phoenix
+#
+# Copyright (c) 2017-2018 RWTH Aachen University, Germany,
+# Virtual Reality & Immersive Visualization Group.
+#------------------------------------------------------------------------------
+#                                 License
+#
+# Licensed under the 3-Clause BSD License (the "License");
+# you may not use this file except in compliance with the License.
+# See the file LICENSE for the full text.
+# You may obtain a copy of the License at
+#
+#     https://opensource.org/licenses/BSD-3-Clause
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#------------------------------------------------------------------------------
+
+set(EXECUTE_CLANG_TIDY__CLANG_TIDY_EXECUTABLE "/usr/local/Cellar/llvm/5.0.1/bin/clang-tidy")
+
+
+set(EXECUTE_CLANG_TIDY__CHECKS
+  boost-use-to-string
+  bugprone-*
+  clang-analyzer-*
+  cppcoreguidelines-*
+  google-*
+  hicpp-*
+  misc-*
+  modernize-
+  mpi-*
+  performance-*
+  readability-*
+  )
+string (REPLACE ";" "," EXECUTE_CLANG_TIDY__CHECKS__COMMA "${EXECUTE_CLANG_TIDY__CHECKS}")
+
+
+# check if newer than stamp -> needs clang-tidy
+set(EXECUTE_CLANG_TIDY__SOURCES_TO_TIDY)
+foreach(EXECUTE_CLANG_TIDY__SOURCE ${EXECUTE_CLANG_TIDY__SOURCES})
+  if(${EXECUTE_CLANG_TIDY__SOURCE} IS_NEWER_THAN ${EXECUTE_CLANG_TIDY__STAMP_FILE})
+    list(APPEND EXECUTE_CLANG_TIDY__SOURCES_TO_TIDY ${EXECUTE_CLANG_TIDY__SOURCE})
+  endif()
+endforeach()
+
+
+set(EXECUTE_CLANG_TIDY__INCLUDE_DIRECTORIES
+  ${EXECUTE_CLANG_TIDY__TARGET_INCLUDE_DIRECTORIES}
+  ${EXECUTE_CLANG_TIDY__TARGET_INTERFACE_INCLUDE_DIRECTORIES}
+  )
+list(REMOVE_DUPLICATES
+  EXECUTE_CLANG_TIDY__INCLUDE_DIRECTORIES
+  )
+
+
+set(EXECUTE_CLANG_TIDY__EXTRA_ARGS
+  "-extra-arg='-std=c++14'"
+  )
+foreach(EXECUTE_CLANG_TIDY__INCLUDE_DIRECTORY
+    ${EXECUTE_CLANG_TIDY__INCLUDE_DIRECTORIES})
+  list(APPEND EXECUTE_CLANG_TIDY__EXTRA_ARGS
+    "-extra-arg='-I${EXECUTE_CLANG_TIDY__INCLUDE_DIRECTORY}'")
+endforeach()
+foreach(EXECUTE_CLANG_TIDY__SYSTEM_INCLUDE_DIRECTORY
+    ${EXECUTE_CLANG_TIDY__TARGET_INTERFACE_SYSTEM_INCLUDE_DIRECTORIES})
+  list(APPEND EXECUTE_CLANG_TIDY__EXTRA_ARGS
+    "-extra-arg='-isystem${EXECUTE_CLANG_TIDY__SYSTEM_INCLUDE_DIRECTORY}'")
+endforeach()
+
+
+set(EXECUTE_CLANG_TIDY__COMMAND_LINE
+  "${EXECUTE_CLANG_TIDY__CLANG_TIDY_EXECUTABLE}"
+  "-checks='${EXECUTE_CLANG_TIDY__CHECKS__COMMA}'"
+  "-warnings-as-errors='${EXECUTE_CLANG_TIDY__CHECKS__COMMA}'"
+  "-header-filter=.*"
+  "${EXECUTE_CLANG_TIDY__EXTRA_ARGS}"
+  ${EXECUTE_CLANG_TIDY__SOURCES_TO_TIDY}
+  )
+string(REPLACE ";" " "
+  EXECUTE_CLANG_TIDY__COMMAND_LINE_FORMATTED
+  "${EXECUTE_CLANG_TIDY__COMMAND_LINE}"
+  )
+
+
+file(WRITE
+  ${EXECUTE_CLANG_TIDY__TARGET_BINARY_DIR}/clang-tidy.sh
+  "#!/bin/bash\n"
+  "${EXECUTE_CLANG_TIDY__COMMAND_LINE_FORMATTED}"
+  )
+
+
+message("executing clang-tidy ...")
+
+execute_process(
+  COMMAND sh ${EXECUTE_CLANG_TIDY__TARGET_BINARY_DIR}/clang-tidy.sh
+  RESULT_VARIABLE EXECUTE_CLANG_TIDY__CLANG_TIDY_RESULT
+  OUTPUT_VARIABLE EXECUTE_CLANG_TIDY__CLANG_TIDY_OUTPUT
+  ERROR_VARIABLE EXECUTE_CLANG_TIDY__CLANG_TIDY_ERROR
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+  ERROR_STRIP_TRAILING_WHITESPACE
+  )
+
+if ("${EXECUTE_CLANG_TIDY__CLANG_TIDY_OUTPUT}" MATCHES "^.*(error|warning).*$"
+    OR NOT EXECUTE_CLANG_TIDY__CLANG_TIDY_RESULT EQUAL 0)
+    message ("${EXECUTE_CLANG_TIDY__CLANG_TIDY_OUTPUT}")
+    message ("${EXECUTE_CLANG_TIDY__CLANG_TIDY_ERRORS}")
+    message (FATAL_ERROR "Clang-Tidy found problems with your code")
+  endif ()
+
+message("... done.")