CMakeLists.txt

# --------------------------------------------------------------------------- #
#    Main CMake file for SMS++ BranchAndXSolver                           #
#                                                                             #
#    This file allows one to build the library using CMake.                   #
#    To do so, you can use the following commands:                            #
#                                                                             #
#        $ cmake -S <source-path> -B <build-path>                             #
#        $ cmake --build <build-path>                                         #
#                                                                             #
#    The following command also installs the library in the system:           #
#                                                                             #
#        $ cmake --build <build-path> --target install                        #
#                                                                             #
#                              Donato Meoli                                   #
#                         Dipartimento di Informatica                         #
#                             Universita' di Pisa                             #
# --------------------------------------------------------------------------- #
cmake_minimum_required(VERSION 3.21)
cmake_policy(VERSION 3.15)
include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/DeriveVersion.cmake)
smspp_derive_version(SMSPP_MODULE_VERSION)

project(BranchAndXSolver
        VERSION ${SMSPP_MODULE_VERSION}
        DESCRIPTION "SMS++ BranchAndXSolver module"
        HOMEPAGE_URL https://gitlab.com/smspp/branchandxsolver
        LANGUAGES CXX)

# These variables make the code harder to read but easier to change.
set(modName ${PROJECT_NAME})

# C-safe form of modName for the preprocessor macros in <modName>Config.h
string(MAKE_C_IDENTIFIER "${modName}" modMacro)
set(modNamespace "SMS++")

# Find out if it's being called by the umbrella.
get_directory_property(hasParent PARENT_DIRECTORY)

# This adds the cmake directory to the module search paths,
# allowing us to use our modules.
list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

# ----- Settings ------------------------------------------------------------ #
# This creates an ENABLE_TESTING option (default: ON) and enables the testing
# using the ctest executable.
# See: https://cmake.org/cmake/help/latest/manual/ctest.1.html
include(CTest)

# Sets the default build type (if none was specified).
# See: https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html
include(BuildType)

# ----- Requirements -------------------------------------------------------- #
# If it's not being called by the umbrella, we need to
# look for the system-installed libraries.
if (NOT hasParent)
    find_package(SMS++ REQUIRED)
endif ()

# ----- Configuration header ------------------------------------------------ #
# This will generate a *Config.h header in the build directory.
configure_file(cmake/${modName}Config.h.in ${modName}Config.h)

# ----- RPATH --------------------------------------------------------------- #
# The installed libraries and executables look for the libraries of the same
# installation relative to their own location, so that the installed tree can
# be moved as a whole; the directories of the external libraries are kept.
include(GNUInstallDirs)
if (NOT CMAKE_INSTALL_RPATH)
    if (APPLE)
        set(rpathOrigin "@loader_path")
    else ()
        set(rpathOrigin "$ORIGIN")
    endif ()
    file(RELATIVE_PATH binToLib ${CMAKE_INSTALL_FULL_BINDIR}
            ${CMAKE_INSTALL_FULL_LIBDIR})
    set(CMAKE_INSTALL_RPATH "${rpathOrigin}" "${rpathOrigin}/${binToLib}")
endif ()
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)

# ----- Library ------------------------------------------------------------- #
# With the BUILD_SHARED_LIBS variable we can specify if the library will
# be STATIC or SHARED, so no reason to do it now.
add_library(${modName})
target_compile_features(${modName} PUBLIC cxx_std_20)

# The name of the shared library carries the version of its binary interface,
# which any minor release may change while the major version is 0, and then
# any major release.
if (PROJECT_VERSION_MAJOR EQUAL 0)
    set(soVersion ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR})
else ()
    set(soVersion ${PROJECT_VERSION_MAJOR})
endif ()
set_target_properties(${modName} PROPERTIES
        VERSION ${PROJECT_VERSION}
        SOVERSION ${soVersion})

# The classes of the module register themselves in the factory from a static
# initialiser, and a linker that drops what looks unused takes the
# registration away with it: the target tells whoever links it to keep the
# symbol that forces the module in, or the library as a whole where naming
# the symbol is not enough.
if (BUILD_SHARED_LIBS)
    if (MSVC)
        target_link_options(${modName} INTERFACE
                "/INCLUDE:SMSpp_force_load_${modName}")
    elseif (UNIX AND (NOT APPLE))
        # the ELF linker decides by the symbols a regular object asks for, so
        # naming the symbol is not enough and the library has to be kept
        target_link_options(${modName} INTERFACE "LINKER:--no-as-needed")
    elseif (APPLE)
        # ld64 keeps a dylib that provides a symbol to the link, one asked
        # for by -u included, even under -dead_strip_dylibs
        target_link_options(${modName} INTERFACE
                "LINKER:-u,_SMSpp_force_load_${modName}")
    endif ()
endif ()

# When adding source files with target_sources(), PRIVATE means that the files
# should only be added to this library, whereas PUBLIC means they should be
# added to this library and to any target that links to it.
# Note: do not GLOB files here.
target_sources(${modName} PRIVATE
        src/BranchAndXSolver.cpp)

# Different INSTALL_INTERFACE and BUILD_INTERFACE paths are used when
# generating the target import file (***Targets.cmake).
target_include_directories(
        ${modName} PUBLIC
        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
        $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
        $<INSTALL_INTERFACE:include/${modNamespace}>)

# When linking other targets to the library with target_link_libraries(),
# PUBLIC means they will be linked also to the targets that depend on this
# library.
target_link_libraries(${modName} PUBLIC ${modNamespace}::SMS++)

# This alias is defined so that executables in this same project can use
# the library with this notation.
add_library(${modNamespace}::${modName} ALIAS ${modName})

# ----- Subdirectories ------------------------------------------------------ #
if (BUILD_TESTING)
    add_subdirectory(test)
endif ()

# ----- Install instructions ------------------------------------------------ #
# The following commands are used when installing the library
# and its CMake configuration files on the system.
# They are not required for local builds (see below).

include(GNUInstallDirs)

# Install the library
install(TARGETS ${modName}
        EXPORT ${modName}Targets
        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} # .dll
        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} # .so .dylib
        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}) # .lib

# Install the headers
install(DIRECTORY include/
        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${modNamespace})

# Install the auto-generated configuration header (see above).
install(FILES ${PROJECT_BINARY_DIR}/${modName}Config.h
        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/${modNamespace})

# (Generate and) install the target import file, that allows other
# CMake projects to import the target.
install(EXPORT ${modName}Targets
        NAMESPACE ${modNamespace}::
        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/${modName})

# Generate the package version file, that allows other
# CMake projects to know the version.
include(CMakePackageConfigHelpers)
write_basic_package_version_file(
        ${CMAKE_CURRENT_BINARY_DIR}/${modName}ConfigVersion.cmake
        VERSION ${PROJECT_VERSION}
        COMPATIBILITY AnyNewerVersion)

# Generate the package configuration file, that allows other
# CMake projects to find the library with find_package().
configure_package_config_file(
        ${CMAKE_CURRENT_LIST_DIR}/cmake/${modName}Config.cmake.in
        ${CMAKE_CURRENT_BINARY_DIR}/${modName}Config.cmake
        INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/${modName})

# Install the package version and configuration files.
install(FILES
        ${CMAKE_CURRENT_BINARY_DIR}/${modName}Config.cmake
        ${CMAKE_CURRENT_BINARY_DIR}/${modName}ConfigVersion.cmake
        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/${modName})

# ----- Add the build tree to RPATH------------------------------------------ #
# Add the binary directory to RPATH, so executables that use
# dynamic loading will look into it.
if (hasParent)
    set(SMSPP_BUILD_RPATH
            "${SMSPP_BUILD_RPATH};${CMAKE_CURRENT_BINARY_DIR}"
            PARENT_SCOPE)
endif ()

# ----- Packaging support --------------------------------------------------- #
# The following commands allow one to build a proper package using CPack.
# See: https://cmake.org/cmake/help/latest/manual/cpack.1.html

# Using this with the umbrella project is too messy.
if (NOT hasParent)
    set(CPACK_PACKAGE_VENDOR "SMS++ Team")
    set(CPACK_PACKAGE_CONTACT "Donato Meoli")
    set(CPACK_PACKAGE_DESCRIPTION_SUMMARY ${PROJECT_DESCRIPTION})
    set(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_CURRENT_LIST_DIR}/LICENSE")
    set(CPACK_RESOURCE_FILE_README "${CMAKE_CURRENT_LIST_DIR}/README.md")
    set(CPACK_SOURCE_IGNORE_FILES
            \\\\.git/
            \\\\.gitignore$
            \\\\.gitattributes$)
    include(CPack)
endif ()

# --------------------------------------------------------------------------- #
# Remove from the search paths the cmake directory we added at the beginning.
list(REMOVE_AT CMAKE_MODULE_PATH -1)