SDL_ibus.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#ifdef HAVE_IBUS_IBUS_H
#include "SDL_ibus.h"
#include "SDL_dbus.h"

#ifdef SDL_USE_LIBDBUS

//#include "../../video/SDL_sysvideo.h"
#include "../../events/SDL_keyboard_c.h"

#ifdef SDL_VIDEO_DRIVER_X11
#include "../../video/x11/SDL_x11video.h"
#endif

#include <sys/inotify.h>
#include <unistd.h>
#include <fcntl.h>

static const char IBUS_PATH[] = "/org/freedesktop/IBus";

static const char IBUS_SERVICE[] = "org.freedesktop.IBus";
static const char IBUS_INTERFACE[] = "org.freedesktop.IBus";
static const char IBUS_INPUT_INTERFACE[] = "org.freedesktop.IBus.InputContext";

static const char IBUS_PORTAL_SERVICE[] = "org.freedesktop.portal.IBus";
static const char IBUS_PORTAL_INTERFACE[] = "org.freedesktop.IBus.Portal";
static const char IBUS_PORTAL_INPUT_INTERFACE[] = "org.freedesktop.IBus.InputContext";

static const char *ibus_service = NULL;
static const char *ibus_interface = NULL;
static const char *ibus_input_interface = NULL;
static char *input_ctx_path = NULL;
static SDL_Rect ibus_cursor_rect = { 0, 0, 0, 0 };
static DBusConnection *ibus_conn = NULL;
static bool ibus_is_portal_interface = false;
static char *ibus_addr_file = NULL;
static int inotify_fd = -1, inotify_wd = -1;

static Uint32 IBus_ModState(void)
{
    Uint32 ibus_mods = 0;
    SDL_Keymod sdl_mods = SDL_GetModState();

    // Not sure about MOD3, MOD4 and HYPER mappings
    if (sdl_mods & SDL_KMOD_LSHIFT) {
        ibus_mods |= IBUS_SHIFT_MASK;
    }
    if (sdl_mods & SDL_KMOD_CAPS) {
        ibus_mods |= IBUS_LOCK_MASK;
    }
    if (sdl_mods & SDL_KMOD_LCTRL) {
        ibus_mods |= IBUS_CONTROL_MASK;
    }
    if (sdl_mods & SDL_KMOD_LALT) {
        ibus_mods |= IBUS_MOD1_MASK;
    }
    if (sdl_mods & SDL_KMOD_NUM) {
        ibus_mods |= IBUS_MOD2_MASK;
    }
    if (sdl_mods & SDL_KMOD_MODE) {
        ibus_mods |= IBUS_MOD5_MASK;
    }
    if (sdl_mods & SDL_KMOD_LGUI) {
        ibus_mods |= IBUS_SUPER_MASK;
    }
    if (sdl_mods & SDL_KMOD_RGUI) {
        ibus_mods |= IBUS_META_MASK;
    }

    return ibus_mods;
}

static bool IBus_EnterVariant(DBusConnection *conn, DBusMessageIter *iter, SDL_DBusContext *dbus,
                                  DBusMessageIter *inside, const char *struct_id, size_t id_size)
{
    DBusMessageIter sub;
    if (dbus->message_iter_get_arg_type(iter) != DBUS_TYPE_VARIANT) {
        return false;
    }

    dbus->message_iter_recurse(iter, &sub);

    if (dbus->message_iter_get_arg_type(&sub) != DBUS_TYPE_STRUCT) {
        return false;
    }

    dbus->message_iter_recurse(&sub, inside);

    if (dbus->message_iter_get_arg_type(inside) != DBUS_TYPE_STRING) {
        return false;
    }

    dbus->message_iter_get_basic(inside, &struct_id);
    if (!struct_id || SDL_strncmp(struct_id, struct_id, id_size) != 0) {
        return false;
    }
    return true;
}

static bool IBus_GetDecorationPosition(DBusConnection *conn, DBusMessageIter *iter, SDL_DBusContext *dbus,
                                           Uint32 *start_pos, Uint32 *end_pos)
{
    DBusMessageIter sub1, sub2, array;

    if (!IBus_EnterVariant(conn, iter, dbus, &sub1, "IBusText", sizeof("IBusText"))) {
        return false;
    }

    dbus->message_iter_next(&sub1);
    dbus->message_iter_next(&sub1);
    dbus->message_iter_next(&sub1);

    if (!IBus_EnterVariant(conn, &sub1, dbus, &sub2, "IBusAttrList", sizeof("IBusAttrList"))) {
        return false;
    }

    dbus->message_iter_next(&sub2);
    dbus->message_iter_next(&sub2);

    if (dbus->message_iter_get_arg_type(&sub2) != DBUS_TYPE_ARRAY) {
        return false;
    }

    dbus->message_iter_recurse(&sub2, &array);

    while (dbus->message_iter_get_arg_type(&array) == DBUS_TYPE_VARIANT) {
        DBusMessageIter sub;
        if (IBus_EnterVariant(conn, &array, dbus, &sub, "IBusAttribute", sizeof("IBusAttribute"))) {
            Uint32 type;

            dbus->message_iter_next(&sub);
            dbus->message_iter_next(&sub);

            // From here on, the structure looks like this:
            // Uint32 type: 1=underline, 2=foreground, 3=background
            // Uint32 value: for underline it's 0=NONE, 1=SINGLE, 2=DOUBLE,
            // 3=LOW,  4=ERROR
            // for foreground and background it's a color
            // Uint32 start_index: starting position for the style (utf8-char)
            // Uint32 end_index: end position for the style (utf8-char)

            dbus->message_iter_get_basic(&sub, &type);
            // We only use the background type to determine the selection
            if (type == 3) {
                Uint32 start = -1;
                dbus->message_iter_next(&sub);
                dbus->message_iter_next(&sub);
                if (dbus->message_iter_get_arg_type(&sub) == DBUS_TYPE_UINT32) {
                    dbus->message_iter_get_basic(&sub, &start);
                    dbus->message_iter_next(&sub);
                    if (dbus->message_iter_get_arg_type(&sub) == DBUS_TYPE_UINT32) {
                        dbus->message_iter_get_basic(&sub, end_pos);
                        *start_pos = start;
                        return true;
                    }
                }
            }
        }
        dbus->message_iter_next(&array);
    }
    return false;
}

static const char *IBus_GetVariantText(DBusConnection *conn, DBusMessageIter *iter, SDL_DBusContext *dbus)
{
    // The text we need is nested weirdly, use dbus-monitor to see the structure better
    const char *text = NULL;
    DBusMessageIter sub;

    if (!IBus_EnterVariant(conn, iter, dbus, &sub, "IBusText", sizeof("IBusText"))) {
        return NULL;
    }

    dbus->message_iter_next(&sub);
    dbus->message_iter_next(&sub);

    if (dbus->message_iter_get_arg_type(&sub) != DBUS_TYPE_STRING) {
        return NULL;
    }
    dbus->message_iter_get_basic(&sub, &text);

    return text;
}

static bool IBus_GetVariantCursorPos(DBusConnection *conn, DBusMessageIter *iter, SDL_DBusContext *dbus,
                                         Uint32 *pos)
{
    dbus->message_iter_next(iter);

    if (dbus->message_iter_get_arg_type(iter) != DBUS_TYPE_UINT32) {
        return false;
    }

    dbus->message_iter_get_basic(iter, pos);

    return true;
}

static DBusHandlerResult IBus_MessageHandler(DBusConnection *conn, DBusMessage *msg, void *user_data)
{
    SDL_DBusContext *dbus = (SDL_DBusContext *)user_data;

    if (dbus->message_is_signal(msg, ibus_input_interface, "CommitText")) {
        DBusMessageIter iter;
        const char *text;

        dbus->message_iter_init(msg, &iter);
        text = IBus_GetVariantText(conn, &iter, dbus);

        SDL_SendKeyboardText(text);

        return DBUS_HANDLER_RESULT_HANDLED;
    }

    if (dbus->message_is_signal(msg, ibus_input_interface, "UpdatePreeditText")) {
        DBusMessageIter iter;
        const char *text;

        dbus->message_iter_init(msg, &iter);
        text = IBus_GetVariantText(conn, &iter, dbus);

        if (text) {
            Uint32 pos, start_pos, end_pos;
            bool has_pos = false;
            bool has_dec_pos = false;

            dbus->message_iter_init(msg, &iter);
            has_dec_pos = IBus_GetDecorationPosition(conn, &iter, dbus, &start_pos, &end_pos);
            if (!has_dec_pos) {
                dbus->message_iter_init(msg, &iter);
                has_pos = IBus_GetVariantCursorPos(conn, &iter, dbus, &pos);
            }

            if (has_dec_pos) {
                SDL_SendEditingText(text, start_pos, end_pos - start_pos);
            } else if (has_pos) {
                SDL_SendEditingText(text, pos, -1);
            } else {
                SDL_SendEditingText(text, -1, -1);
            }
        }

        //SDL_IBus_UpdateTextInputArea(SDL_GetKeyboardFocus());

        return DBUS_HANDLER_RESULT_HANDLED;
    }

    if (dbus->message_is_signal(msg, ibus_input_interface, "HidePreeditText")) {
        SDL_SendEditingText("", 0, 0);
        return DBUS_HANDLER_RESULT_HANDLED;
    }

    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}

static char *IBus_ReadAddressFromFile(const char *file_path)
{
    char addr_buf[1024];
    bool success = false;
    FILE *addr_file;

    addr_file = fopen(file_path, "r");
    if (!addr_file) {
        return NULL;
    }

    while (fgets(addr_buf, sizeof(addr_buf), addr_file)) {
        if (SDL_strncmp(addr_buf, "IBUS_ADDRESS=", sizeof("IBUS_ADDRESS=") - 1) == 0) {
            size_t sz = SDL_strlen(addr_buf);
            if (addr_buf[sz - 1] == '\n') {
                addr_buf[sz - 1] = 0;
            }
            if (addr_buf[sz - 2] == '\r') {
                addr_buf[sz - 2] = 0;
            }
            success = true;
            break;
        }
    }

    (void)fclose(addr_file);

    if (success) {
        return SDL_strdup(addr_buf + (sizeof("IBUS_ADDRESS=") - 1));
    } else {
        return NULL;
    }
}

static char *IBus_GetDBusAddressFilename(void)
{
    SDL_DBusContext *dbus;
    const char *disp_env;
    char config_dir[PATH_MAX];
    char *display = NULL;
    const char *addr;
    const char *conf_env;
    char *key;
    char file_path[PATH_MAX];
    const char *host;
    char *disp_num, *screen_num;

    if (ibus_addr_file) {
        return SDL_strdup(ibus_addr_file);
    }

    dbus = SDL_DBus_GetContext();
    if (!dbus) {
        return NULL;
    }

    // Use this environment variable if it exists.
    addr = SDL_getenv("IBUS_ADDRESS");
    if (addr && *addr) {
        return SDL_strdup(addr);
    }

    /* Otherwise, we have to get the hostname, display, machine id, config dir
       and look up the address from a filepath using all those bits, eek. */
    disp_env = SDL_getenv("DISPLAY");

    if (!disp_env || !*disp_env) {
        display = SDL_strdup(":0.0");
    } else {
        display = SDL_strdup(disp_env);
    }

    host = display;
    disp_num = SDL_strrchr(display, ':');
    screen_num = SDL_strrchr(display, '.');

    if (!disp_num) {
        SDL_free(display);
        return NULL;
    }

    *disp_num = 0;
    disp_num++;

    if (screen_num) {
        *screen_num = 0;
    }

    if (!*host) {
        const char *session = SDL_getenv("XDG_SESSION_TYPE");
        if (session && SDL_strcmp(session, "wayland") == 0) {
            host = "unix-wayland";
        } else {
            host = "unix";
        }
    }

    SDL_memset(config_dir, 0, sizeof(config_dir));

    conf_env = SDL_getenv("XDG_CONFIG_HOME");
    if (conf_env && *conf_env) {
        SDL_strlcpy(config_dir, conf_env, sizeof(config_dir));
    } else {
        const char *home_env = SDL_getenv("HOME");
        if (!home_env || !*home_env) {
            SDL_free(display);
            return NULL;
        }
        (void)SDL_snprintf(config_dir, sizeof(config_dir), "%s/.config", home_env);
    }

    key = SDL_DBus_GetLocalMachineId();

    if (!key) {
        SDL_free(display);
        return NULL;
    }

    SDL_memset(file_path, 0, sizeof(file_path));
    (void)SDL_snprintf(file_path, sizeof(file_path), "%s/ibus/bus/%s-%s-%s",
                       config_dir, key, host, disp_num);
    dbus->free(key);
    SDL_free(display);

    return SDL_strdup(file_path);
}

static bool IBus_CheckConnection(SDL_DBusContext *dbus);

static void SDLCALL IBus_SetCapabilities(void *data, const char *name, const char *old_val,
                                         const char *hint)
{
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    if (IBus_CheckConnection(dbus)) {
        Uint32 caps = IBUS_CAP_FOCUS;

        if (hint && SDL_strstr(hint, "composition")) {
            caps |= IBUS_CAP_PREEDIT_TEXT;
        }
        if (hint && SDL_strstr(hint, "candidates")) {
            // FIXME, turn off native candidate rendering
        }

        SDL_DBus_CallVoidMethodOnConnection(ibus_conn, ibus_service, input_ctx_path, ibus_input_interface, "SetCapabilities",
                                            DBUS_TYPE_UINT32, &caps, DBUS_TYPE_INVALID);
    }
}

static bool IBus_SetupConnection(SDL_DBusContext *dbus, const char *addr)
{
    const char *client_name = "SDL3_Application";
    const char *path = NULL;
    bool result = false;
    DBusObjectPathVTable ibus_vtable;

    SDL_zero(ibus_vtable);
    ibus_vtable.message_function = &IBus_MessageHandler;

    /* try the portal interface first. Modern systems have this in general,
       and sandbox things like FlakPak and Snaps, etc, require it. */

    ibus_is_portal_interface = true;
    ibus_service = IBUS_PORTAL_SERVICE;
    ibus_interface = IBUS_PORTAL_INTERFACE;
    ibus_input_interface = IBUS_PORTAL_INPUT_INTERFACE;
    ibus_conn = dbus->session_conn;

    result = SDL_DBus_CallMethodOnConnection(ibus_conn, ibus_service, IBUS_PATH, ibus_interface, "CreateInputContext",
                                             DBUS_TYPE_STRING, &client_name, DBUS_TYPE_INVALID,
                                             DBUS_TYPE_OBJECT_PATH, &path, DBUS_TYPE_INVALID);
    if (!result) {
        ibus_is_portal_interface = false;
        ibus_service = IBUS_SERVICE;
        ibus_interface = IBUS_INTERFACE;
        ibus_input_interface = IBUS_INPUT_INTERFACE;
        ibus_conn = dbus->connection_open_private(addr, NULL);

        if (!ibus_conn) {
            return false; // oh well.
        }

        dbus->connection_flush(ibus_conn);

        if (!dbus->bus_register(ibus_conn, NULL)) {
            ibus_conn = NULL;
            return false;
        }

        dbus->connection_flush(ibus_conn);

        result = SDL_DBus_CallMethodOnConnection(ibus_conn, ibus_service, IBUS_PATH, ibus_interface, "CreateInputContext",
                                                 DBUS_TYPE_STRING, &client_name, DBUS_TYPE_INVALID,
                                                 DBUS_TYPE_OBJECT_PATH, &path, DBUS_TYPE_INVALID);
    } else {
        // re-using dbus->session_conn
        dbus->connection_ref(ibus_conn);
    }

    if (result) {
        char matchstr[128];
        (void)SDL_snprintf(matchstr, sizeof(matchstr), "type='signal',interface='%s'", ibus_input_interface);
        SDL_free(input_ctx_path);
        input_ctx_path = SDL_strdup(path);
        SDL_AddHintCallback(SDL_HINT_IME_IMPLEMENTED_UI, IBus_SetCapabilities, NULL);
        dbus->bus_add_match(ibus_conn, matchstr, NULL);
        dbus->connection_try_register_object_path(ibus_conn, input_ctx_path, &ibus_vtable, dbus, NULL);
        dbus->connection_flush(ibus_conn);
    }

    return result;
}

static bool IBus_CheckConnection(SDL_DBusContext *dbus)
{
    if (!dbus) {
        return false;
    }

    if (ibus_conn && dbus->connection_get_is_connected(ibus_conn)) {
        return true;
    }

    if (inotify_fd > 0 && inotify_wd > 0) {
        char buf[1024];
        ssize_t readsize = read(inotify_fd, buf, sizeof(buf));
        if (readsize > 0) {

            char *p;
            bool file_updated = false;

            for (p = buf; p < buf + readsize; /**/) {
                struct inotify_event *event = (struct inotify_event *)p;
                if (event->len > 0) {
                    char *addr_file_no_path = SDL_strrchr(ibus_addr_file, '/');
                    if (!addr_file_no_path) {
                        return false;
                    }

                    if (SDL_strcmp(addr_file_no_path + 1, event->name) == 0) {
                        file_updated = true;
                        break;
                    }
                }

                p += sizeof(struct inotify_event) + event->len;
            }

            if (file_updated) {
                char *addr = IBus_ReadAddressFromFile(ibus_addr_file);
                if (addr) {
                    bool result = IBus_SetupConnection(dbus, addr);
                    SDL_free(addr);
                    return result;
                }
            }
        }
    }

    return false;
}

bool SDL_IBus_Init(void)
{
    bool result = false;
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    if (dbus) {
        char *addr_file = IBus_GetDBusAddressFilename();
        char *addr;
        char *addr_file_dir;

        if (!addr_file) {
            return false;
        }

        addr = IBus_ReadAddressFromFile(addr_file);
        if (!addr) {
            SDL_free(addr_file);
            return false;
        }

        if (ibus_addr_file) {
            SDL_free(ibus_addr_file);
        }
        ibus_addr_file = SDL_strdup(addr_file);

        if (inotify_fd < 0) {
            inotify_fd = inotify_init();
            fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
        }

        addr_file_dir = SDL_strrchr(addr_file, '/');
        if (addr_file_dir) {
            *addr_file_dir = 0;
        }

        inotify_wd = inotify_add_watch(inotify_fd, addr_file, IN_CREATE | IN_MODIFY);
        SDL_free(addr_file);

        result = IBus_SetupConnection(dbus, addr);
        SDL_free(addr);

        // don't use the addr_file if using the portal interface.
        if (result && ibus_is_portal_interface) {
            if (inotify_fd > 0) {
                if (inotify_wd > 0) {
                    inotify_rm_watch(inotify_fd, inotify_wd);
                    inotify_wd = -1;
                }
                close(inotify_fd);
                inotify_fd = -1;
            }
        }
    }

    return result;
}

void SDL_IBus_Quit(void)
{
    SDL_DBusContext *dbus;

    if (input_ctx_path) {
        SDL_free(input_ctx_path);
        input_ctx_path = NULL;
    }

    if (ibus_addr_file) {
        SDL_free(ibus_addr_file);
        ibus_addr_file = NULL;
    }

    dbus = SDL_DBus_GetContext();

    // if using portal, ibus_conn == session_conn; don't release it here.
    if (dbus && ibus_conn && !ibus_is_portal_interface) {
        dbus->connection_close(ibus_conn);
        dbus->connection_unref(ibus_conn);
    }

    ibus_conn = NULL;
    ibus_service = NULL;
    ibus_interface = NULL;
    ibus_input_interface = NULL;
    ibus_is_portal_interface = false;

    if (inotify_fd > 0 && inotify_wd > 0) {
        inotify_rm_watch(inotify_fd, inotify_wd);
        inotify_wd = -1;
    }

    // !!! FIXME: should we close(inotify_fd) here?

    SDL_RemoveHintCallback(SDL_HINT_IME_IMPLEMENTED_UI, IBus_SetCapabilities, NULL);

    SDL_memset(&ibus_cursor_rect, 0, sizeof(ibus_cursor_rect));
}

static void IBus_SimpleMessage(const char *method)
{
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    if ((input_ctx_path) && (IBus_CheckConnection(dbus))) {
        SDL_DBus_CallVoidMethodOnConnection(ibus_conn, ibus_service, input_ctx_path, ibus_input_interface, method, DBUS_TYPE_INVALID);
    }
}

void SDL_IBus_SetFocus(bool focused)
{
    const char *method = focused ? "FocusIn" : "FocusOut";
    IBus_SimpleMessage(method);
}

void SDL_IBus_Reset(void)
{
    IBus_SimpleMessage("Reset");
}

bool SDL_IBus_ProcessKeyEvent(Uint32 keysym, Uint32 keycode, bool down)
{
    Uint32 result = 0;
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    if (IBus_CheckConnection(dbus)) {
        Uint32 mods = IBus_ModState();
        Uint32 ibus_keycode = keycode - 8;
        if (!down) {
            mods |= (1 << 30); // IBUS_RELEASE_MASK
        }
        if (!SDL_DBus_CallMethodOnConnection(ibus_conn, ibus_service, input_ctx_path, ibus_input_interface, "ProcessKeyEvent",
                                             DBUS_TYPE_UINT32, &keysym, DBUS_TYPE_UINT32, &ibus_keycode, DBUS_TYPE_UINT32, &mods, DBUS_TYPE_INVALID,
                                             DBUS_TYPE_BOOLEAN, &result, DBUS_TYPE_INVALID)) {
            result = 0;
        }
    }

    //SDL_IBus_UpdateTextInputArea(SDL_GetKeyboardFocus());

    return (result != 0);
}

void SDL_IBus_PumpEvents(void)
{
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    if (IBus_CheckConnection(dbus)) {
        dbus->connection_read_write(ibus_conn, 0);

        while (dbus->connection_dispatch(ibus_conn) == DBUS_DISPATCH_DATA_REMAINS) {
            // Do nothing, actual work happens in IBus_MessageHandler
        }
    }
}

#endif // SDL_USE_LIBDBUS

#endif