obs-studio/cmake/Modules/IDLFileHelper.cmake

macro(add_idl_files generated_files)
	foreach(filename ${ARGN})
		get_filename_component(file_we ${filename} NAME_WE)
		get_filename_component(file_path ${filename} PATH)

		set(file_c ${file_we}_i.c)
		set(file_h ${file_we}.h)
		set(bin_file_h ${CMAKE_CURRENT_BINARY_DIR}/${file_h})
		set(bin_file_c ${CMAKE_CURRENT_BINARY_DIR}/${file_c})

		if(MSVC)
			add_custom_command(
				OUTPUT ${bin_file_h} ${bin_file_c}
				DEPENDS ${filename}
				COMMAND midl /h ${file_h} /iid ${file_c} /notlb ${CMAKE_CURRENT_SOURCE_DIR}/${filename}
				WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
		else()
			execute_process(COMMAND echo
				COMMAND ${CMAKE_C_COMPILER} -v -x c++ -E -
				ERROR_VARIABLE cpp_inc_output
				OUTPUT_QUIET
				ERROR_STRIP_TRAILING_WHITESPACE)

			string(REPLACE ";" " " include_dirs ${cpp_inc_output})
			string(REPLACE "\n" ";" include_dirs ${cpp_inc_output})

			set(include_params)
			foreach(include_dir ${include_dirs})
				string(SUBSTRING ${include_dir} 0 1 first_char)
				if(${first_char} STREQUAL " ")
					string(LENGTH "${include_dir}" include_dir_len)
					math(EXPR include_dir_len "${include_dir_len} - 1")
					string(SUBSTRING ${include_dir} 1 ${include_dir_len} include_dir)
					set(include_params "-I\"${include_dir}\" ${include_params}")
				endif()
			endforeach()

			if(WIN32)
				separate_arguments(include_params WINDOWS_COMMAND ${include_params})
			endif()

			add_custom_command(
				OUTPUT ${file_h}
				DEPENDS ${filename}
				COMMAND ${CMAKE_WIDL} ${include_params} -h -o ${file_h} ${CMAKE_CURRENT_SOURCE_DIR}/${filename}
				WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})

			file(WRITE ${bin_file_c} "#include <initguid.h>\n#include <${file_h}>\n")
		endif()

		set_source_files_properties(
			${bin_file_h}
			${bin_file_c}
			PROPERTIES
			GENERATED TRUE)

		set(${generated_files} ${${generated_file}}
			${bin_file_h}
			${bin_file_c})

		set_source_files_properties(${filename}
			PROPERTIES
			HEADER_FILE_ONLY TRUE)
	endforeach(filename ${ARGN})
endmacro(add_idl_files)