From b464a1fb0b954d689f44760f607e3925ba78021f Mon Sep 17 00:00:00 2001
From: jmcarcell <jmcarcell@users.noreply.github.com>
Date: Fri, 6 Sep 2024 22:14:05 +0200
Subject: [PATCH] Add a Key4hepConfig file

---
 cmake/Key4hepConfig.cmake | 84 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 cmake/Key4hepConfig.cmake

diff --git a/cmake/Key4hepConfig.cmake b/cmake/Key4hepConfig.cmake
new file mode 100644
index 000000000..1309ed9f8
--- /dev/null
+++ b/cmake/Key4hepConfig.cmake
@@ -0,0 +1,84 @@
+macro(key4hep_set_compiler_flags)
+  if (DEFINED KEY4HEP_SET_COMPILER_FLAGS AND NOT KEY4HEP_SET_COMPILER_FLAGS)
+    return()
+  endif()
+
+  set(COMPILER_FLAGS "-fPIC -Wall -Wextra -Wpedantic -Wshadow -Wdeprecated")
+
+  if(CMAKE_CXX_COMPILER_ID MATCHES "^(Apple)?Clang$")
+    set(COMPILER_FLAGS "${COMPILER_FLAGS} -Winconsistent-missing-override -Wheader-hygiene -fcolor-diagnostics")
+  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    set(COMPILER_FLAGS "${COMPILER_FLAGS} -fdiagnostics-color=always")
+  endif()
+
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${COMPILER_FLAGS}")
+
+endmacro()
+
+macro(key4hep_set_build_type)
+
+  # For ccmake and cmake-gui
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
+    "None" "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
+
+  if(NOT CMAKE_CONFIGURATION_TYPES)
+    if(NOT CMAKE_BUILD_TYPE)
+      set(CMAKE_BUILD_TYPE RelWithDebInfo
+        CACHE STRING "Choose the type of build, options are: None, Release, MinSizeRel, Debug, RelWithDebInfo (default)"
+        FORCE
+        )
+    else()
+      set(CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}"
+        CACHE STRING "Choose the type of build, options are: None, Release, MinSizeRel, Debug, RelWithDebInfo (default)"
+        FORCE
+        )
+    endif()
+  endif()
+endmacro()
+
+macro(key4hep_set_cxx_standard_and_extensions)
+  set(CMAKE_CXX_STANDARD 20 CACHE STRING "")
+
+  if(NOT CMAKE_CXX_STANDARD MATCHES "20|23")
+    message(FATAL_ERROR "Unsupported C++ standard: ${CMAKE_CXX_STANDARD}, supported values are 20 and 23")
+  endif()
+
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
+  set(CMAKE_CXX_EXTENSIONS OFF)
+
+endmacro()
+
+macro(key4hep_set_rpath)
+  #  When building, don't use the install RPATH already (but later on when installing)
+  set(CMAKE_SKIP_BUILD_RPATH FALSE)         # don't skip the full RPATH for the build tree
+  set(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE) # use always the build RPATH for the build tree
+  set(CMAKE_MACOSX_RPATH TRUE)              # use RPATH for MacOSX
+  set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE) # point to directories outside the build tree to the install RPATH
+
+  # Check whether to add RPATH to the installation (the build tree always has the RPATH enabled)
+  if(APPLE)
+    set(CMAKE_INSTALL_NAME_DIR "@rpath")
+    set(CMAKE_INSTALL_RPATH "@loader_path/../lib")    # self relative LIBDIR
+    # the RPATH to be used when installing, but only if it's not a system directory
+    list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/lib" isSystemDir)
+    if("${isSystemDir}" STREQUAL "-1")
+      set(CMAKE_INSTALL_RPATH "@loader_path/../lib")
+    endif()
+  elseif(DEFINED KEY4HEP_SET_RPATH AND NOT KEY4HEP_SET_RPATH)
+    set(CMAKE_SKIP_INSTALL_RPATH TRUE)           # skip the full RPATH for the install tree
+  else()
+    set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/${LIBDIR}") # install LIBDIR
+    # the RPATH to be used when installing, but only if it's not a system directory
+    list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/lib" isSystemDir)
+    if("${isSystemDir}" STREQUAL "-1")
+      set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/${LIBDIR}")
+    endif()
+  endif()
+endmacro()
+
+###################################################
+
+key4hep_set_compiler_flags()
+key4hep_set_build_type()
+key4hep_set_cxx_standard_and_extensions()
+key4hep_set_rpath()