Cmake: Release Channel

Add support for an `openPMD_RELEASE_CHANNEL` variable.
This var can be set in conda/spack/pypi/... release channels to
something different than "source" and we can ask the user later on
for it via a simple runtime API call.

Author: ax3l

CMakeLists.txt

@@ -29,6 +29,12 @@ if(WIN32)
 endif()
 
 
+# Release channel #############################################################
+#
+set(openPMD_RELEASE_CHANNEL "source"
+    CACHE STRING "Describes the method openPMD-api was installed with.")
+
+
 # Options and Variants ########################################################
 #
 function(openpmd_option name description default)
@@ -271,6 +277,9 @@ set(IO_ADIOS1_SOURCE
 add_library(openPMD ${CORE_SOURCE} ${IO_SOURCE})
 add_library(openPMD::openPMD ALIAS openPMD)
 
+# release channel
+target_compile_definitions(openPMD PUBLIC "-DOPENPMD_RELEASE_CHANNEL=${OPENPMD_RELEASE_CHANNEL}")
+
 # properties
 target_compile_features(openPMD
     PUBLIC cxx_std_11
@@ -832,6 +841,7 @@ message("")
 message("openPMD build configuration:")
 message("  library Version: ${openPMD_VERSION}")
 message("  openPMD Standard: ${openPMD_STANDARD_VERSION}")
+message("  release channel: ${openPMD_RELEASE_CHANNEL}")
 message("  C++ Compiler: ${CMAKE_CXX_COMPILER_ID} "
                         "${CMAKE_CXX_COMPILER_VERSION} "
                         "${CMAKE_CXX_COMPILER_WRAPPER}")

include/openPMD/version.hpp

@@ -35,3 +35,8 @@
 #define OPENPMD_STANDARD_MIN_MAJOR 1
 #define OPENPMD_STANDARD_MIN_MINOR 0
 #define OPENPMD_STANDARD_MIN_PATCH 0
+
+// release channel
+#if !defined(OPENPMD_RELEASE_CHANNEL)
+#   define OPENPMD_RELEASE_CHANNEL "source"
+#endif

openPMDConfig.cmake.in

@@ -4,6 +4,8 @@ include(CMakeFindDependencyMacro)
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/Modules")
 
+set(openPMD_RELEASE_CHANNEL @openPMD_RELEASE_CHANNEL@)
+
 set(openPMD_HAVE_MPI @openPMD_HAVE_MPI@)
 if(openPMD_HAVE_MPI)
     find_dependency(MPI)