CMakeLists.txt

cmake_minimum_required(VERSION 3.0.0)

##
## PROJECT
## name and version
##
project(nlohmann_json VERSION 2.1.1)

##
## OPTIONS
##
option(JSON_BuildTests "Build the unit tests" ON)

##
## CONFIGURATION
##
set(NLOHMANN_JSON_TARGET_NAME               ${PROJECT_NAME})
set(NLOHMANN_JSON_SOURCE_DIR                "src/")
set(NLOHMANN_JSON_CONFIG_INSTALL_DIR        "lib/cmake/${PROJECT_NAME}")
set(NLOHMANN_JSON_INCLUDE_INSTALL_DIR       "include")
set(NLOHMANN_JSON_HEADER_INSTALL_DIR        "${NLOHMANN_JSON_INCLUDE_INSTALL_DIR}/nlohmann")
set(NLOHMANN_JSON_TARGETS_EXPORT_NAME       "${PROJECT_NAME}Targets")
set(NLOHMANN_JSON_CMAKE_CONFIG_TEMPLATE     "cmake/config.cmake.in")
set(NLOHMANN_JSON_CMAKE_CONFIG_DIR          "${CMAKE_CURRENT_BINARY_DIR}/cmake_config")
set(NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE "${NLOHMANN_JSON_CMAKE_CONFIG_DIR}/${PROJECT_NAME}ConfigVersion.cmake")
set(NLOHMANN_JSON_CMAKE_PROJECT_CONFIG_FILE "${NLOHMANN_JSON_CMAKE_CONFIG_DIR}/${PROJECT_NAME}Config.cmake")

##
## TARGET
## create target and add include path
##
add_library(${NLOHMANN_JSON_TARGET_NAME} INTERFACE)

target_include_directories(
    ${NLOHMANN_JSON_TARGET_NAME}
    INTERFACE $<INSTALL_INTERFACE:include/>
)
            
##
## TESTS
## create and configure the unit test target
##
if(JSON_BuildTests)
    enable_testing()
    include_directories(${NLOHMANN_JSON_SOURCE_DIR})
    add_subdirectory(test)
endif()

##
## INSTALL
## install header files, generate and install cmake config files for find_package()
##
include(CMakePackageConfigHelpers)
write_basic_package_version_file(
    ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE} COMPATIBILITY SameMajorVersion
)
configure_package_config_file(
    ${NLOHMANN_JSON_CMAKE_CONFIG_TEMPLATE}
    ${NLOHMANN_JSON_CMAKE_PROJECT_CONFIG_FILE}
    INSTALL_DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
)
install(
    DIRECTORY ${NLOHMANN_JSON_SOURCE_DIR}
    DESTINATION ${NLOHMANN_JSON_HEADER_INSTALL_DIR}
)
install(
    FILES ${NLOHMANN_JSON_CMAKE_PROJECT_CONFIG_FILE} ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE}
    DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
)
install(
    TARGETS ${NLOHMANN_JSON_TARGET_NAME}
    EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
    INCLUDES DESTINATION ${NLOHMANN_JSON_INCLUDE_INSTALL_DIR}
)
install(
    EXPORT ${NLOHMANN_JSON_TARGETS_EXPORT_NAME}
    DESTINATION ${NLOHMANN_JSON_CONFIG_INSTALL_DIR}
)