CardputerZero-AppBuilder/sdk/cmake/CZApp.cmake

# CZApp.cmake — build a CardputerZero LVGL app as a shared library.
#
# Usage:
#   list(APPEND CMAKE_MODULE_PATH "${path_to_sdk}/cmake")
#   include(CZApp)
#   cz_add_lvgl_app(my_app SOURCES src/foo.c src/bar.c)
#
# The resulting target:
#   * is a SHARED library named "my_app" (→ libmy_app.dylib / .so / my_app.dll)
#   * can reference any LVGL API — LVGL symbols are resolved at dlopen time
#     against the host's (emulator or APPLaunch) LVGL instance
#   * exports exactly the symbols declared in <cz_app.h>
#
# Required variables (auto-discovered from this file's location):
#   CZ_SDK_DIR       — root of the sdk/ tree (include/ + cmake/ below it)
#   CZ_EMULATOR_DIR  — the emulator checkout that supplies lvgl.h. Defaults to
#                      ${CZ_SDK_DIR}/../emulator (AppBuilder layout).
#
# See docs/DESKTOP_DEV.md for the rules an app must follow.

if(NOT DEFINED CZ_SDK_DIR)
    get_filename_component(CZ_SDK_DIR "${CMAKE_CURRENT_LIST_DIR}/.." ABSOLUTE)
endif()

if(NOT DEFINED CZ_EMULATOR_DIR)
    get_filename_component(CZ_EMULATOR_DIR "${CZ_SDK_DIR}/../emulator" ABSOLUTE)
endif()

set(CZ_LVGL_DIR "${CZ_EMULATOR_DIR}/lib/lvgl")

if(NOT EXISTS "${CZ_LVGL_DIR}/lvgl.h")
    message(FATAL_ERROR
        "CZApp: LVGL headers not found at ${CZ_LVGL_DIR}/lvgl.h. "
        "Did you run `git submodule update --init --recursive` in the "
        "CardputerZero-AppBuilder checkout?")
endif()

function(cz_add_lvgl_app TARGET)
    # Options:
    #   NO_KBD_STUBS — skip the default weak lv_sdl_keyboard_create/handler
    #                  shim. Apps that want real keyboard input (using the
    #                  emulator's real SDL keyboard driver) should set this so
    #                  that the symbols stay unresolved in the .dylib/.so and
    #                  get bound to the host at dlopen time.
    cmake_parse_arguments(CZA "NO_KBD_STUBS" "" "SOURCES" ${ARGN})
    if(NOT CZA_SOURCES)
        message(FATAL_ERROR "cz_add_lvgl_app(${TARGET}): no SOURCES given")
    endif()

    add_library(${TARGET} SHARED ${CZA_SOURCES})

    set_target_properties(${TARGET} PROPERTIES
        C_STANDARD 11
        CXX_STANDARD 17
        PREFIX "lib"          # Windows: libfoo.dll for parity with Unix
        POSITION_INDEPENDENT_CODE ON
    )

    target_include_directories(${TARGET} PRIVATE
        "${CZ_SDK_DIR}/include"        # cz_app.h + lv_conf.h
        "${CZ_LVGL_DIR}"               # lvgl.h
        "${CZ_LVGL_DIR}/demos"         # demos/widgets/lv_demo_widgets.h etc.
    )

    # Pinned LVGL config — must byte-match the host's.
    target_compile_definitions(${TARGET} PRIVATE LV_CONF_INCLUDE_SIMPLE=1)

    # Link-time behaviour: LVGL symbols stay unresolved in the app library; the
    # host resolves them at dlopen/LoadLibrary time.
    if(APPLE)
        target_link_options(${TARGET} PRIVATE -undefined dynamic_lookup)
    elseif(WIN32)
        # Windows needs an import library for LVGL; see docs/DESKTOP_DEV.md §4.
        # Until that lands, flag builds so they fail loud instead of producing
        # a silently broken .dll.
        message(WARNING
            "cz_add_lvgl_app: Windows import-lib support is not implemented "
            "yet (see DESKTOP_DEV.md §4). Build will likely fail at link.")
    else()
        target_link_options(${TARGET}
            PRIVATE "LINKER:--unresolved-symbols=ignore-all")
    endif()

    # Compatibility shim: the current emulator dlsym's "ui_init" and calls it.
    # Until the emulator switches to app_main/app_event (separate task), emit
    # a one-line ui_init thunk that forwards to app_main(lv_screen_active()).
    set(_thunk "${CMAKE_CURRENT_BINARY_DIR}/cz_${TARGET}_ui_init_thunk.c")
    file(WRITE "${_thunk}"
"/* Auto-generated by CZApp.cmake — do not edit. */\n"
"#include <cz_app.h>\n"
"void ui_init(void) { app_main(lv_screen_active()); }\n"
    )
    target_sources(${TARGET} PRIVATE "${_thunk}")

    # Also emit a default weak app_event so apps that only care about UI can
    # skip providing one. Strong definitions in the app override this.
    set(_weak "${CMAKE_CURRENT_BINARY_DIR}/cz_${TARGET}_app_event_default.c")
    file(WRITE "${_weak}"
"/* Auto-generated by CZApp.cmake — default no-op app_event. */\n"
"#include <cz_app.h>\n"
"__attribute__((weak)) void app_event(int type, void *data) { (void)type; (void)data; }\n"
    )
    target_sources(${TARGET} PRIVATE "${_weak}")

    if(CZA_NO_KBD_STUBS)
        return()
    endif()

    # Default weak keyboard stubs. The emulator always dlsyms
    # lv_sdl_keyboard_create / lv_sdl_keyboard_handler; when the app provides
    # neither, the emulator falls back to a bare keypad indev with no read_cb
    # and LVGL floods the log with "indev_read_cb is not registered". These
    # stubs give the emulator a real (but inert) indev so the log stays clean.
    # Apps that want real keyboard input pass NO_KBD_STUBS and let the
    # emulator's real lv_sdl_keyboard_* resolve via dlopen.
    set(_kbd "${CMAKE_CURRENT_BINARY_DIR}/cz_${TARGET}_kbd_default.c")
    file(WRITE "${_kbd}"
"/* Auto-generated by CZApp.cmake — default no-op SDL keyboard stubs. */\n"
"#include <cz_app.h>\n"
"static void _cz_default_kbd_read(lv_indev_t *indev, lv_indev_data_t *data) {\n"
"    (void)indev;\n"
"    data->state = LV_INDEV_STATE_RELEASED;\n"
"    data->key = 0;\n"
"}\n"
"__attribute__((weak)) lv_indev_t *lv_sdl_keyboard_create(void) {\n"
"    lv_indev_t *kb = lv_indev_create();\n"
"    lv_indev_set_type(kb, LV_INDEV_TYPE_KEYPAD);\n"
"    lv_indev_set_read_cb(kb, _cz_default_kbd_read);\n"
"    return kb;\n"
"}\n"
"__attribute__((weak)) void lv_sdl_keyboard_handler(void *ev) { (void)ev; }\n"
    )
    target_sources(${TARGET} PRIVATE "${_kbd}")
endfunction()