/* Runtime null guard for wl_proxy_add_listener — interposed via LD_PRELOAD.
 * Qt6 Wayland QPA passes NULL proxies during initialization on Redox.
 * This shim prevents the page fault at null+8 (proxy->object.implementation)
 * by returning an error code instead of crashing.
 *
 * Cross-referenced with libwayland wayland-client.c:649.
 */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>

/* Original function pointer */
static int (*real_wl_proxy_add_listener)(void *proxy,
    void (**implementation)(void), void *data) = NULL;

static void *(*real_wl_proxy_get_display)(void *proxy) = NULL;
static unsigned int (*real_wl_proxy_get_version)(void *proxy) = NULL;

static void init(void) {
    real_wl_proxy_add_listener = dlsym(RTLD_NEXT, "wl_proxy_add_listener");
    real_wl_proxy_get_display = dlsym(RTLD_NEXT, "wl_proxy_get_display");
    real_wl_proxy_get_version = dlsym(RTLD_NEXT, "wl_proxy_get_version");
}

int wl_proxy_add_listener(void *proxy,
    void (**implementation)(void), void *data) {
    if (!real_wl_proxy_add_listener) init();
    if (!proxy) {
        fprintf(stderr, "wayland-guard: wl_proxy_add_listener(NULL) prevented crash\n");
        return -1;
    }
    return real_wl_proxy_add_listener(proxy, implementation, data);
}

void *wl_proxy_get_display(void *proxy) {
    if (!real_wl_proxy_get_display) init();
    if (!proxy) return NULL;
    return real_wl_proxy_get_display(proxy);
}

unsigned int wl_proxy_get_version(void *proxy) {
    if (!real_wl_proxy_get_version) init();
    if (!proxy) return 0;
    return real_wl_proxy_get_version(proxy);
}