FindCython.cmake

#
# Cython
#

# This finds the "cython" executable in your PATH, and then in some standard
# paths:

find_program(CYTHON_BIN NAMES cython cython3 cython2)
SET(CYTHON_FLAGS --cplus --fast-fail -3)

SET(Cython_FOUND FALSE)
IF (CYTHON_BIN)
    # Try to run Cython, to make sure it works:
    execute_process(
        COMMAND ${CYTHON_BIN} ${CYTHON_FLAGS} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/cython_test.pyx
        RESULT_VARIABLE CYTHON_RESULT
        OUTPUT_VARIABLE CYTHON_OUTPUT
        ERROR_VARIABLE CYTHON_ERROR
    )
    if (CYTHON_RESULT EQUAL 0)
        # Only if cython exits with the return code 0, we know that all is ok:
        SET(Cython_FOUND TRUE)
        SET(Cython_Compilation_Failed FALSE)
    else (CYTHON_RESULT EQUAL 0)
        SET(Cython_Compilation_Failed TRUE)
    endif (CYTHON_RESULT EQUAL 0)
ENDIF (CYTHON_BIN)


IF (Cython_FOUND)
    IF (NOT Cython_FIND_QUIETLY)
        MESSAGE(STATUS "Found CYTHON: ${CYTHON_BIN}")
    ENDIF (NOT Cython_FIND_QUIETLY)
ELSE (Cython_FOUND)
    IF (Cython_FIND_REQUIRED)
        if(Cython_Compilation_Failed)
            MESSAGE(STATUS "Found CYTHON: ${CYTHON_BIN}")
            # On Win the testing of Cython does not return any accessible value, so the test is not carried out.
            # Fresh Cython install was tested and works.
            IF(NOT MSVC)
                MESSAGE(FATAL_ERROR
                    "Your Cython version is too old. Please upgrade Cython."
                    "STDOUT: ${CYTHON_OUTPUT}"
                    "STDERROR: ${CYTHON_ERROR}"
                )
            ENDIF(NOT MSVC)
        else(Cython_Compilation_Failed)
            MESSAGE(FATAL_ERROR "Could not find Cython. Please install Cython.")
        endif(Cython_Compilation_Failed)
    ENDIF (Cython_FIND_REQUIRED)
ENDIF (Cython_FOUND)


# This allows to link Cython files
# Examples:
# 1) to compile assembly.pyx to assembly.so:
#   CYTHON_ADD_MODULE(assembly)
# 2) to compile assembly.pyx and something.cpp to assembly.so:
#   CYTHON_ADD_MODULE(assembly something.cpp)

if(NOT CYTHON_INCLUDE_DIRECTORIES)
    set(CYTHON_INCLUDE_DIRECTORIES .)
endif(NOT CYTHON_INCLUDE_DIRECTORIES)

# Cythonizes the .pyx files into .cpp file (but doesn't compile it)
macro(CYTHON_ADD_MODULE_PYX cpp_name pyx_name)
    # Allow the user to specify dependencies as optional arguments
    set(DEPENDS ${DEPENDS} ${ARGN})
    add_custom_command(
        OUTPUT ${cpp_name}
        COMMAND ${CYTHON_BIN}
        ARGS ${CYTHON_FLAGS} -I ${CYTHON_INCLUDE_DIRECTORIES} -o ${cpp_name} ${pyx_name}
        DEPENDS ${DEPENDS} ${pyx_name}
        COMMENT "Cythonizing ${pyx_name}")
endmacro(CYTHON_ADD_MODULE_PYX)