OpenCV/opencv_contrib/modules/julia/cmake/FindJulia.cmake

# Original FindJulia.cmake from https://github.com/QuantStack/xtensor-julia-cookiecutter/blob/master/%7B%7Bcookiecutter.github_project_name%7D%7D/cmake/FindJulia.cmake
if(Julia_FOUND)
    return()
endif()

####################
# Julia Executable #
####################

find_program(Julia_EXECUTABLE julia DOC "Julia executable")

#################
# Julia Version #
#################

if(Julia_EXECUTABLE)
    message(STATUS "Found Julia executable: " ${Julia_EXECUTABLE})

    execute_process(
        COMMAND "${Julia_EXECUTABLE}" --startup-file=no --version
        OUTPUT_VARIABLE Julia_VERSION_STRING
    )
else()
    return()
endif()

string(
    REGEX REPLACE ".*([0-9]+\\.[0-9]+\\.[0-9]+).*" "\\1"
      Julia_VERSION_STRING "${Julia_VERSION_STRING}"
)

MESSAGE(STATUS "Julia_VERSION_STRING: ${Julia_VERSION_STRING}")

##################
# Julia Includes #
##################

set(JULIA_HOME_NAME "Sys.BINDIR")
if(${Julia_VERSION_STRING} VERSION_LESS "0.7.0")
    set(JULIA_HOME_NAME "JULIA_HOME")
else()
    set(USING_LIBDL "using Libdl")
endif()

if(DEFINED ENV{JULIA_INCLUDE_DIRS})
    set(Julia_INCLUDE_DIRS $ENV{JULIA_INCLUDE_DIRS}
        CACHE STRING "Location of Julia include files")
elseif(Julia_EXECUTABLE)
    execute_process(
        COMMAND ${Julia_EXECUTABLE} --startup-file=no -E "julia_include_dir = joinpath(match(r\"(.*)(bin)\",${JULIA_HOME_NAME}).captures[1],\"include\",\"julia\")\n
            if !isdir(julia_include_dir)  # then we're running directly from build\n
            julia_base_dir_aux = splitdir(splitdir(${JULIA_HOME_NAME})[1])[1]  # useful for running-from-build\n
            julia_include_dir = joinpath(julia_base_dir_aux, \"usr\", \"include\" )\n
            julia_include_dir *= \";\" * joinpath(julia_base_dir_aux, \"src\", \"support\" )\n
            julia_include_dir *= \";\" * joinpath(julia_base_dir_aux, \"src\" )\n
            end\n
            julia_include_dir"
        OUTPUT_VARIABLE Julia_INCLUDE_DIRS
    )

    string(REGEX REPLACE "\"" "" Julia_INCLUDE_DIRS "${Julia_INCLUDE_DIRS}")
    string(REGEX REPLACE "\n" "" Julia_INCLUDE_DIRS "${Julia_INCLUDE_DIRS}")
    set(Julia_INCLUDE_DIRS ${Julia_INCLUDE_DIRS}
        CACHE PATH "Location of Julia include files")
elseif(Julia_PREFIX)
    set(Julia_INCLUDE_DIRS ${Julia_PREFIX}/include/julia)
endif()
MESSAGE(STATUS "Julia_INCLUDE_DIRS:   ${Julia_INCLUDE_DIRS}")

###################
# Julia Libraries #
###################

if(WIN32)
    set(CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES} .a)
endif()

if(Julia_EXECUTABLE)
    execute_process(
        COMMAND ${Julia_EXECUTABLE} --startup-file=no -E "${USING_LIBDL}\nabspath(Libdl.dlpath((ccall(:jl_is_debugbuild, Cint, ()) != 0) ? \"libjulia-debug\" : \"libjulia\"))"
        OUTPUT_VARIABLE Julia_LIBRARY
    )

    string(REGEX REPLACE "\"" "" Julia_LIBRARY "${Julia_LIBRARY}")
    string(REGEX REPLACE "\n" "" Julia_LIBRARY "${Julia_LIBRARY}")
    string(STRIP "${Julia_LIBRARY}" Julia_LIBRARY)

    if(WIN32)
        get_filename_component(Julia_LIBRARY_DIR ${Julia_LIBRARY} DIRECTORY)
        get_filename_component(Julia_LIBRARY_DIR ${Julia_LIBRARY_DIR} DIRECTORY)
        find_library(win_Julia_LIBRARY
            NAMES libjulia.dll.a
            PATHS "${Julia_LIBRARY_DIR}/lib"
            NO_DEFAULT_PATH
        )
        set(Julia_LIBRARY "${win_Julia_LIBRARY}")
    endif()

    set(Julia_LIBRARY "${Julia_LIBRARY}"
        CACHE PATH "Julia library")
else()
    find_library(Julia_LIBRARY NAMES libjulia.${Julia_VERSION_STRING}.dylib julia libjulia libjulia.dll.a CMAKE_FIND_ROOT_PATH_BOTH)
endif()

get_filename_component(Julia_LIBRARY_DIR ${Julia_LIBRARY} DIRECTORY)

MESSAGE(STATUS "Julia_LIBRARY_DIR:    ${Julia_LIBRARY_DIR}")
MESSAGE(STATUS "Julia_LIBRARY:        ${Julia_LIBRARY}")

##############
# JULIA_HOME #
##############

if(Julia_EXECUTABLE)
    execute_process(
        COMMAND ${Julia_EXECUTABLE} --startup-file=no -E "${JULIA_HOME_NAME}"
        OUTPUT_VARIABLE JULIA_HOME
    )

    string(REGEX REPLACE "\"" "" JULIA_HOME "${JULIA_HOME}")
    string(REGEX REPLACE "\n" "" JULIA_HOME "${JULIA_HOME}")

    MESSAGE(STATUS "JULIA_HOME:           ${JULIA_HOME}")

###################
# libLLVM version #
###################

    execute_process(
        COMMAND ${Julia_EXECUTABLE} --startup-file=no -E "Base.libllvm_version"
        OUTPUT_VARIABLE Julia_LLVM_VERSION
    )

    string(REGEX REPLACE "\"" "" Julia_LLVM_VERSION "${Julia_LLVM_VERSION}")
    string(REGEX REPLACE "\n" "" Julia_LLVM_VERSION "${Julia_LLVM_VERSION}")

    MESSAGE(STATUS "Julia_LLVM_VERSION:   ${Julia_LLVM_VERSION}")
endif()

##################################
# Check for Existence of Headers #
##################################

find_path(Julia_MAIN_HEADER julia.h HINTS ${Julia_INCLUDE_DIRS})

#######################################
# Determine if we are on 32 or 64 bit #
#######################################

if(Julia_EXECUTABLE)
    execute_process(
        COMMAND ${Julia_EXECUTABLE} --startup-file=no -E "Sys.WORD_SIZE"
        OUTPUT_VARIABLE Julia_WORD_SIZE
    )
    string(REGEX REPLACE "\n" "" Julia_WORD_SIZE "${Julia_WORD_SIZE}")
    MESSAGE(STATUS "Julia_WORD_SIZE:      ${Julia_WORD_SIZE}")
endif()

###########################
# FindPackage Boilerplate #
###########################

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Julia
    REQUIRED_VARS   Julia_LIBRARY Julia_LIBRARY_DIR Julia_INCLUDE_DIRS Julia_MAIN_HEADER Julia_EXECUTABLE
    VERSION_VAR     Julia_VERSION_STRING
    FAIL_MESSAGE    "Julia not found"
)