Implement automatic format checker

Add format check in GitLab CI configuration file.
Add CMake target for format checker .
Add neede CMake files and shell scripts.
Add label in GitLab CI configuration file such that it can be
properly sorted on CDash.
The checker is disabled till we format the complete code base.

.clang-format

+---
+AccessModifierOffset: -2
+AlignAfterOpenBracket: Align
+#AlignConsecutiveMacros: true
+AlignConsecutiveAssignments: true
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlines: Right
+AlignOperands: true
+AlignTrailingComments: true
+#AllowAllArgumentsOnNextLine: true
+#AllowAllConstructorInitializersOnNextLine: true
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: true
+AllowShortCaseLabelsOnASingleLine: true
+AllowShortFunctionsOnASingleLine: All
+AllowShortIfStatementsOnASingleLine: true
+#AllowShortLambdasOnASingleLine: All
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: false
+BinPackParameters: false
+BreakBeforeBinaryOperators: NonAssignment
+BreakBeforeBraces: Attach
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializers: AfterColon
+BreakInheritanceList: AfterColon
+ColumnLimit: 80
+CompactNamespaces: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+ConstructorInitializerIndentWidth: 2
+ContinuationIndentWidth: 2
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat: false
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: true
+IncludeBlocks: Preserve
+IndentCaseLabels: true
+IndentPPDirectives: None
+IndentWidth: 2
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: true
+Language: Cpp
+MaxEmptyLinesToKeep: 2
+NamespaceIndentation: All
+ObjCBinPackProtocolList: Auto
+ObjCBlockIndentWidth: 2
+PenaltyBreakAssignment: 2
+PointerAlignment: Left
+ReflowComments: true
+SortIncludes: true
+SortUsingDeclarations: true
+SpaceAfterCStyleCast: true
+#SpaceAfterLogicalNot: true
+SpaceAfterTemplateKeyword: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCpp11BracedList: true
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeParens: ControlStatements
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 2
+SpacesInAngles: false
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+TabWidth: 8
+UseTab: Never
+
+...

.gitlab-ci.yml

 stages:
+  - check
   - build
   - documentation
   
@@ -41,7 +42,6 @@ CbmRoot_Continuous:
     - echo "export FAIRSOFT_VERSION=jun19p1" >> Dart.cfg
     - echo "export FAIRROOT_VERSION=v18.2.0" >> Dart.cfg
     - echo "export SIMPATH=/cvmfs/fairroot.gsi.de/fairsoft/\${FAIRSOFT_VERSION}" >> Dart.cfg
-    - echo "export FAIRROOTPATH=/cvmfs/fairroot.gsi.de/fairroot/\${FAIRROOT_VERSION}_fairsoft-\${FAIRSOFT_VERSION}" >> Dart.cfg 
     - echo "export BUILDDIR=$PWD/build" >> Dart.cfg
     - echo "export SOURCEDIR=$PWD" >> Dart.cfg
     - echo "export NCPU=5" >> Dart.cfg
@@ -57,7 +57,7 @@ CbmRoot_Continuous:
     - cd ..
 
 #FormatCheck:
-#  stage: build
+#  stage: check
 #  tags:
 #    - CbmRoot
 #  only:
@@ -66,31 +66,26 @@ CbmRoot_Continuous:
 #    variables:
 #      - $CI_MERGE_REQUEST_PROJECT_PATH == "computing/cbmroot"
 #  script:
-#    - set -xv
 #    - echo "export FAIRSOFT_VERSION=jun19p1" > env.sh
 #    - echo "export FAIRROOT_VERSION=v18.2.0" >> env.sh
 #    - echo "export SIMPATH=/cvmfs/fairroot.gsi.de/fairsoft/\${FAIRSOFT_VERSION}" >> env.sh
+#    - echo "export FAIRROOTPATH=/cvmfs/fairroot.gsi.de/fairroot/\${FAIRROOT_VERSION}_fairsoft-\${FAIRSOFT_VERSION}" >> env.sh
 #    - echo "export BUILDDIR=$PWD/build" >> env.sh
 #    - echo "export SOURCEDIR=$PWD" >> env.sh
-#    - echo "export PATH=\$SIMPATH/bin:$PATH" >> env.sh
-#    - ls
-#    - pwd
-#    - cat env.sh
+#    - echo "export PATH=/cvmfs/fairroot.gsi.de/clang-format-8.0.1:\$SIMPATH/bin:$PATH:/cvmfs/it.gsi.de/compiler/llvm/6.0.1/bin/" >> env.sh
+#    - echo "export LABEL=format-check_MR-\${CI_MERGE_REQUEST_IID}" >> env.sh
 #    - . ./env.sh && ctest -S cmake/scripts/checkformat.cmake -VV
 
 CbmRoot_Merge:
   stage: build
   tags:
     - CbmRoot
-#  only:
-#    - merge_requests
   only:
     refs:
       - merge_requests
     variables:
       - $CI_MERGE_REQUEST_PROJECT_PATH == "computing/cbmroot"
   script:
-#    - set -xv
     - echo $CI_MERGE_REQUEST_SOURCE_PROJECT_PATH
     - echo $CI_MERGE_REQUEST_PROJECT_PATH
     - if [ "$CI_MERGE_REQUEST_PROJECT_PATH" != "computing/cbmroot" ]; then

CMakeLists.txt

@@ -357,6 +357,14 @@ add_custom_target(cleantest
                   COMMAND ${CMAKE_COMMAND} -P ${CMAKE_SOURCE_DIR}/cmake/scripts/cleantest.cmake
                  )
 
+find_package2(PRIVATE ClangFormat)
+if(ClangFormat_FOUND)
+  add_custom_target(FormatCheck
+    ${CMAKE_COMMAND} -E env FAIRROOT_GIT_CLANG_FORMAT_BIN=${GIT_CLANG_FORMAT_BIN} ${CMAKE_SOURCE_DIR}/cmake/scripts/check-format.sh
+    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+  )
+endif()
+
 Option(BUILD_DOXYGEN "Build Doxygen" OFF)
 if(BUILD_DOXYGEN)
   MESSAGE(STATUS "*** Building the Doxygen documentaion ***")

cmake/modules/FindClangFormat.cmake

+# Defines the following variables:
+#
+#   ClangFormat_FOUND - Found clang-format and git-clang-format
+#   CLANG_FORMAT_BIN - clang-format executable
+#   GIT_CLANG_FORMAT_BIN - git-clang-format executable
+
+find_program(CLANG_FORMAT_BIN
+  NAMES clang-format
+        clang-format-9
+        clang-format-8
+        clang-format-7
+        clang-format-6.0
+        clang-format-5.0
+        clang-format-4.0
+        clang-format-3.9
+        clang-format-3.8
+        clang-format-3.7
+        clang-format-3.6
+        clang-format-3.5
+        clang-format-3.4
+        clang-format-3.3
+)
+
+find_program(GIT_CLANG_FORMAT_BIN
+  NAMES git-clang-format
+        git-clang-format-9
+        git-clang-format-8
+        git-clang-format-7
+        git-clang-format-6.0
+        git-clang-format-5.0
+        git-clang-format-4.0
+        git-clang-format-3.9
+        git-clang-format-3.8
+        git-clang-format-3.7
+        git-clang-format-3.6
+        git-clang-format-3.5
+        git-clang-format-3.4
+        git-clang-format-3.3
+)
+
+Message("GIT_CLANG_FORMAT_BIN: ${GIT_CLANG_FORMAT_BIN}")
+Message("CLANG_FORMAT_BIN: ${CLANG_FORMAT_BIN}")
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(ClangFormat
+  REQUIRED_VARS CLANG_FORMAT_BIN GIT_CLANG_FORMAT_BIN
+)

cmake/scripts/check-format.sh

+#!/bin/bash
+
+BASE_COMMIT=${FAIRROOT_FORMAT_BASE:-HEAD}
+GIT_CLANG_FORMAT_BIN=${FAIRROOT_GIT_CLANG_FORMAT_BIN:-git-clang-format}
+
+FILES=$(git diff --name-only $BASE_COMMIT | grep -E '.*\.(h|hpp|c|C|cpp|cxx|tpl)$' | grep -viE '.*LinkDef.h$')
+RESULT=$($GIT_CLANG_FORMAT_BIN --commit $BASE_COMMIT --diff $FILES --extensions h,hpp,c,C,cpp,cxx,tpl)
+
+if [ "$RESULT" == "no modified files to format" ] || [ "$RESULT" == "clang-format did not modify any files" ]; then
+    echo "format check passed."
+    exit 0
+else
+    echo "ERROR: format check failed. Suggested changes:"
+    echo "$RESULT"
+    exit 1
+fi
+

cmake/scripts/checkformat.cmake

+cmake_host_system_information(RESULT fqdn QUERY FQDN)
+
+set(CTEST_SOURCE_DIRECTORY .)
+set(CTEST_BINARY_DIRECTORY build)
+Set(CTEST_PROJECT_NAME "CbmRoot")
+set(CTEST_CMAKE_GENERATOR "Unix Makefiles")
+set(CTEST_USE_LAUNCHERS ON)
+
+if ("$ENV{CTEST_SITE}" STREQUAL "")
+  set(CTEST_SITE "${fqdn}")
+else()
+  set(CTEST_SITE $ENV{CTEST_SITE})
+endif()
+
+if ("$ENV{LABEL}" STREQUAL "")
+  set(CTEST_BUILD_NAME "format-check")
+else()
+  set(CTEST_BUILD_NAME $ENV{LABEL})
+endif()
+
+ctest_start(Experimental)
+
+ctest_configure(BUILD "${CTEST_BINARY_DIRECTORY}")
+
+ctest_build(TARGET FormatCheck FLAGS "")
+
+ctest_submit()