vengi/cmake/externallib.cmake

set(LIBS_DIR ${PROJECT_SOURCE_DIR}/contrib/libs)

function(var_global)
	foreach(VAR ${ARGN})
		set(${VAR} ${${VAR}} CACHE STRING "" FORCE)
		mark_as_advanced(${VAR})
	endforeach()
endfunction()

#
# macro for the FindLibName.cmake files.
#
# parameters:
# LIB: the library we are trying to find
# HEADERS: the header we are trying to find
# SUFFIX: suffix for the include dir
# VERSION: the operator and version that is given to the pkg-config call (e.g. ">=1.0")
#          (this only works for pkg-config)
#
# Example: engine_find(SDL2_image SDL_image.h SDL2 "")
#
function(engine_find LIB HEADERS SUFFIX VERSION)
	string(TOUPPER ${LIB} PREFIX)
	if (DEFINED ${PREFIX}_FOUND)
		return()
	endif()
	if (DEFINED ${PREFIX}_LOCAL)
		return()
	endif()
	if(CMAKE_SIZEOF_VOID_P EQUAL 8)
		set(_PROCESSOR_ARCH "x64")
	else()
		set(_PROCESSOR_ARCH "x86")
	endif()
	set(_SEARCH_PATHS
		~/Library/Frameworks
		/Library/Frameworks
		/usr/local
		/usr
		/sw # Fink
		/opt/local # DarwinPorts
		/opt/csw # Blastwave
		/opt
		/usr/local/opt
		/usr/local/opt/${LIB}
		$ENV{VCPKG_ROOT}/installed/${_PROCESSOR_ARCH}-windows
		C:/Tools/vcpkg/installed/${_PROCESSOR_ARCH}-windows
		C:/vcpkg/installed/${_PROCESSOR_ARCH}-windows
	)
	find_package(PkgConfig QUIET)
	if (PKG_CONFIG_FOUND)
		pkg_check_modules(_${PREFIX} "${LIB}${VERSION}")
	endif()
	if (NOT ${PREFIX}_FOUND)
		find_path(${PREFIX}_INCLUDE_DIRS
			NAMES ${HEADERS}
			HINTS ENV ${PREFIX}DIR
			PATH_SUFFIXES include include/${SUFFIX} ${SUFFIX}
			PATHS
				${_${PREFIX}_INCLUDE_DIRS}
				${_SEARCH_PATHS}
		)
		find_library(${PREFIX}_LIBRARIES
			NAMES ${LIB} ${PREFIX} ${_${PREFIX}_LIBRARIES}
			HINTS ENV ${PREFIX}DIR
			PATH_SUFFIXES lib64 lib lib/${_PROCESSOR_ARCH}
			PATHS
				${_${PREFIX}_LIBRARY_DIRS}
				${_SEARCH_PATHS}
		)
	else()
		set(${PREFIX}_INCLUDE_DIRS ${_${PREFIX}_INCLUDE_DIRS})
		list(APPEND ${PREFIX}_INCLUDE_DIRS ${_${PREFIX}_INCLUDEDIR})
		set(${PREFIX}_LIBRARIES ${_${PREFIX}_LIBRARIES})
		list(APPEND ${PREFIX}_LIBRARIES ${_${PREFIX}_LIBRARY})
	endif()
	include(FindPackageHandleStandardArgs)
	find_package_handle_standard_args(${LIB} FOUND_VAR ${PREFIX}_FOUND REQUIRED_VARS ${PREFIX}_INCLUDE_DIRS ${PREFIX}_LIBRARIES)
	mark_as_advanced(${PREFIX}_INCLUDE_DIRS ${PREFIX}_LIBRARIES ${PREFIX}_FOUND)
	var_global(${PREFIX}_INCLUDE_DIRS ${PREFIX}_LIBRARIES ${PREFIX}_FOUND)
	unset(PREFIX)
	unset(_SEARCH_PATHS)
	unset(_PROCESSOR_ARCH)
endfunction()

function(engine_find_header_only LIB HEADER SUFFIX VERSION)
	string(TOUPPER ${LIB} PREFIX)
	set(_SEARCH_PATHS
		~/Library/Frameworks
		/Library/Frameworks
		/usr/local
		/usr/local/opt
		/usr/local/opt/${LIB}
		/usr
		/sw # Fink
		/opt/local # DarwinPorts
		/opt/csw # Blastwave
		/opt
	)
	find_package(PkgConfig QUIET)
	if (PKG_CONFIG_FOUND)
		pkg_check_modules(_${PREFIX} "${LIB}${VERSION}")
	endif()
	find_path(${PREFIX}_INCLUDE_DIRS
		NAMES ${HEADER}
		HINTS ENV ${PREFIX}DIR
		PATH_SUFFIXES include include/${SUFFIX} ${SUFFIX}
		PATHS
			${_${PREFIX}_INCLUDE_DIRS}
			${_SEARCH_PATHS}
	)
	include(FindPackageHandleStandardArgs)
	find_package_handle_standard_args(${LIB} FOUND_VAR ${PREFIX}_FOUND REQUIRED_VARS ${PREFIX}_INCLUDE_DIRS)
	mark_as_advanced(${PREFIX}_INCLUDE_DIRS ${PREFIX}_FOUND)
	var_global(${PREFIX}_INCLUDE_DIRS ${PREFIX}_FOUND)
	unset(PREFIX)
	unset(_SEARCH_PATHS)
endfunction()

#
# Add external dependency. It will trigger a find_package and use the system wide install if found
#
# parameters:
# PUBLICHEADER: optional
# LIB: the name of the lib. Must match the FindXXX.cmake module and the pkg-config name of the lib
# SRCS: the list of source files for the bundled lib
# DEFINES: a list of defines (without -D or /D)
#
function(engine_add_library)
	set(_OPTIONS_ARGS)
	set(_ONE_VALUE_ARGS LIB PACKAGE PUBLICHEADER)
	set(_MULTI_VALUE_ARGS SRCS DEFINES)

	cmake_parse_arguments(_ADDLIB "${_OPTIONS_ARGS}" "${_ONE_VALUE_ARGS}" "${_MULTI_VALUE_ARGS}" ${ARGN} )

	if (NOT _ADDLIB_LIB)
		message(FATAL_ERROR "engine_add_library requires the LIB argument")
	endif()
	if (NOT _ADDLIB_SRCS)
		message(FATAL_ERROR "engine_add_library requires the SRCS argument")
	endif()
	if (NOT _ADDLIB_PUBLICHEADER)
		set(_ADDLIB_PUBLICHEADER PUBLIC)
	endif()

	if (_ADDLIB_PACKAGE)
		set(FIND_PACKAGE_NAME ${_ADDLIB_PACKAGE})
	else()
		set(FIND_PACKAGE_NAME ${_ADDLIB_LIB})
	endif()

	string(TOUPPER ${_ADDLIB_LIB} PREFIX)
	if (NOT ${PREFIX}_LOCAL)
		find_package(${FIND_PACKAGE_NAME})
		find_package(${FIND_PACKAGE_NAME})
	endif()
	# now convert it again - looks like find_package exports PREFIX in some versions of cmake, too
	string(TOUPPER ${_ADDLIB_LIB} PREFIX)
	string(TOUPPER ${FIND_PACKAGE_NAME} PKG_PREFIX)
	if (NOT ${PREFIX} STREQUAL ${PKG_PREFIX})
		if (${PKG_PREFIX}_INCLUDE_DIRS)
			set(${PREFIX}_INCLUDE_DIRS ${${PKG_PREFIX}_INCLUDE_DIRS})
		elseif(${PKG_PREFIX}_INCLUDE_DIR)
			set(${PREFIX}_INCLUDE_DIRS ${${PKG_PREFIX}_INCLUDE_DIR})
		else()
			set(${PREFIX}_INCLUDE_DIRS ${${PKG_PREFIX}_INCLUDEDIR})
		endif()
		if (NOT ${PREFIX}_LIBRARIES AND ${PKG_PREFIX}_LIBRARIES)
			set(${PREFIX}_LIBRARIES ${${PKG_PREFIX}_LIBRARIES})
		elseif(NOT ${PREFIX}_LIBRARIES AND ${PKG_PREFIX}_LIBRARY)
			set(${PREFIX}_LIBRARIES ${${PKG_PREFIX}_LIBRARY})
		else()
			message(WARN "Could not find libs for ${PREFIX}")
		endif()
		set(${PREFIX}_FOUND ${${PKG_PREFIX}_FOUND})
		message(STATUS "Found ${PKG_PREFIX} => ${${PREFIX}_FOUND}")
	endif()
	var_global(${PREFIX}_INCLUDE_DIRS ${PREFIX}_LIBRARIES ${PREFIX}_FOUND)
	if (${PREFIX}_FOUND)
		message(STATUS "Found system wide package ${_ADDLIB_LIB}")
		add_library(${_ADDLIB_LIB} INTERFACE)
		add_library(${PKG_PREFIX}::${PKG_PREFIX} ALIAS ${_ADDLIB_LIB})
		if (${PREFIX}_INCLUDE_DIRS)
			target_include_directories(${_ADDLIB_LIB} INTERFACE ${${PREFIX}_INCLUDE_DIRS})
			message(STATUS "${_ADDLIB_LIB}: ${PREFIX}_INCLUDE_DIRS: ${${PREFIX}_INCLUDE_DIRS}")
		endif()
		if (${PREFIX}_LIBRARIES)
			target_link_libraries(${_ADDLIB_LIB} INTERFACE ${${PREFIX}_LIBRARIES})
			message(STATUS "${_ADDLIB_LIB}: ${PREFIX}_LIBRARIES: ${${PREFIX}_LIBRARIES}")
		endif()
	else()
		message(STATUS "Use the bundled lib ${_ADDLIB_LIB}")
		add_library(${_ADDLIB_LIB} STATIC ${_ADDLIB_SRCS})
		add_library(${PKG_PREFIX}::${PKG_PREFIX} ALIAS ${_ADDLIB_LIB})
		target_compile_options(${_ADDLIB_LIB} PRIVATE $<$<CXX_COMPILER_ID:GNU>:-Wno-undef>)
		target_include_directories(${_ADDLIB_LIB} ${_ADDLIB_PUBLICHEADER} ${LIBS_DIR}/${_ADDLIB_LIB})
		set_target_properties(${_ADDLIB_LIB} PROPERTIES COMPILE_DEFINITIONS "${_ADDLIB_DEFINES}")
		set_target_properties(${_ADDLIB_LIB} PROPERTIES FOLDER ${_ADDLIB_LIB})
	endif()
endfunction()