godot-cpp/cmake/python_callouts.cmake

#[=======================================================================[.rst:
python_callouts.cmake
---------------------

This file contains functions which which rely on calling Python

* Generate Trimmed API
* Generate File List
* Generate Bindings
]=======================================================================]


#[[ Generate Trimmed API

The build_profile.py has a __main__ and is used as a tool
Its usage is listed as:
    $ python build_profile.py BUILD_PROFILE INPUT_JSON [OUTPUT_JSON]
]]
function( build_profile_generate_trimmed_api BUILD_PROFILE INPUT_JSON OUTPUT_JSON )
    execute_process(
            COMMAND "${Python3_EXECUTABLE}" "build_profile.py" "${BUILD_PROFILE}" "${INPUT_JSON}" "${OUTPUT_JSON}"
            WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    )
endfunction(  )


#[[ Generate File List

Use the binding_generator.py Python script to determine the list of files that
will be passed to the code generator using extension_api.json.
NOTE: This happens for every configure.]]
function( binding_generator_get_file_list OUT_VAR_NAME API_FILEPATH OUTPUT_DIR )

    # This code snippet will be squashed into a single line
    # The two strings make this a list, in CMake lists are semicolon delimited strings.
    set( PYTHON_SCRIPT
"from binding_generator import print_file_list"
"print_file_list( api_filepath='${API_FILEPATH}',
    output_dir='${OUTPUT_DIR}',
    headers=True,
    sources=True)")
    message( DEBUG "Python:\n${PYTHON_SCRIPT}" )

    # Strip newlines and whitespace to make it a one-liner.
    string( REGEX REPLACE "\n *" " " PYTHON_SCRIPT "${PYTHON_SCRIPT}" )

    execute_process( COMMAND "${Python3_EXECUTABLE}" "-c" "${PYTHON_SCRIPT}"
            WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
            OUTPUT_VARIABLE GENERATED_FILES_LIST
            OUTPUT_STRIP_TRAILING_WHITESPACE
    )

    # Debug output
    message( DEBUG "FileList-Begin" )
    foreach( PATH ${GENERATED_FILES_LIST} )
        message( DEBUG ${PATH} )
    endforeach()

    # Error out if the file list generator returned no files.
    list( LENGTH GENERATED_FILES_LIST LIST_LENGTH )
    if( NOT LIST_LENGTH GREATER 0 )
        message( FATAL_ERROR "File List Generation Failed")
    endif()
    message( STATUS "There are ${LIST_LENGTH} Files to generate" )

    set( ${OUT_VAR_NAME} ${GENERATED_FILES_LIST} PARENT_SCOPE )
endfunction(  )


#[[ Generate Bindings

Using the generated file list, use the binding_generator.py to generate the
godot-cpp bindings. This will run at build time only if there are files
missing. ]]
function( binding_generator_generate_bindings API_FILE USE_TEMPLATE_GET_NODE, BITS, PRECISION, OUTPUT_DIR )
    # This code snippet will be squashed into a single line
    set( PYTHON_SCRIPT
"from binding_generator import generate_bindings"
"generate_bindings(
    api_filepath='${API_FILE}',
    use_template_get_node='${USE_TEMPLATE_GET_NODE}',
    bits='${BITS}',
    precision='${PRECISION}',
    output_dir='${OUTPUT_DIR}')")

    message( DEBUG "Python:\n${PYTHON_SCRIPT}" )

    # Strip newlines and whitespace to make it a one-liner.
    string( REGEX REPLACE "\n *" " " PYTHON_SCRIPT "${PYTHON_SCRIPT}" )

    add_custom_command(OUTPUT ${GENERATED_FILES_LIST}
            COMMAND "${Python3_EXECUTABLE}" "-c" "${PYTHON_SCRIPT}"
            VERBATIM
            WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
            MAIN_DEPENDENCY ${GODOT_GDEXTENSION_API_FILE}
            DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/binding_generator.py
            COMMENT "Generating bindings"
    )
endfunction(  )