webOS: wl_proxy_marshal_constructor_versioned workaround for older versions

Author: cscd98

input/common/wayland_common_webos.c

@@ -23,6 +23,7 @@
 #include <poll.h>
 #include <unistd.h>
 #include <string/stdstring.h>
+#include <dlfcn.h>
 
 #include "wayland_common.h"
 #include "wayland_common_webos.h"
@@ -864,3 +865,112 @@ void shutdown_webos_contexts()
    }
 #endif
 }
+
+/*
+   Backwards compatibility for older versions of libwayland-client that
+   do not have wl_proxy_marshal_constructor_versioned and
+   wl_proxy_marshal_array_constructor_versioned.
+*/
+
+/* Simple DirectMedia Layer
+   Copyright (C) 1997-2023 Sam Lantinga <[email protected] */
+static int parse_msg_signature(const char *signature, int *new_id_index)
+{
+    int count = 0;
+    for (; *signature; ++signature) {
+        switch (*signature) {
+        case 'n':
+            *new_id_index = count;
+            // Intentional fallthrough
+        case 'i':
+        case 'u':
+        case 'f':
+        case 's':
+        case 'o':
+        case 'a':
+        case 'h':
+            ++count;
+        }
+    }
+    return count;
+}
+
+struct wl_proxy *RA_wl_proxy_marshal_constructor_versioned(
+    struct wl_proxy *proxy, uint32_t opcode,
+    const struct wl_interface *iface, uint32_t version, ...)
+{
+    static struct wl_proxy *(*fn)(struct wl_proxy *, uint32_t,
+                                  const struct wl_interface *, uint32_t, ...) = NULL;
+    static int dlsym_called = 0;
+
+    if (!dlsym_called) {
+        fn = dlsym(RTLD_NEXT, "wl_proxy_marshal_constructor_versioned");
+        dlsym_called = 1;
+    }
+
+    if (fn) {
+        /* real symbol exists, just call it */
+        va_list ap;
+        va_start(ap, version);
+        struct wl_proxy *ret = fn(proxy, opcode, iface, version, ap);
+        va_end(ap);
+        return ret;
+    }
+
+    /* fallback path: reconstruct arguments */
+    void *varargs[WL_CLOSURE_MAX_ARGS];
+    int num_args;
+    int new_id_index = -1;
+    struct wl_interface *proxy_interface;
+    struct wl_proxy *id = wl_proxy_create(proxy, iface);
+    if (!id)
+        return NULL;
+
+    proxy_interface = (*(struct wl_interface **)proxy);
+    if (opcode > proxy_interface->method_count)
+        return NULL;
+
+    num_args = parse_msg_signature(proxy_interface->methods[opcode].signature,
+                                   &new_id_index);
+    if (new_id_index < 0)
+        return NULL;
+
+    memset(varargs, 0, sizeof(varargs));
+
+    va_list ap;
+    va_start(ap, version);
+    for (int i = 0; i < num_args; i++)
+        varargs[i] = va_arg(ap, void *);
+    va_end(ap);
+
+    varargs[new_id_index] = id;
+
+    wl_proxy_marshal(proxy, opcode,
+                     varargs[0], varargs[1], varargs[2], varargs[3], varargs[4],
+                     varargs[5], varargs[6], varargs[7], varargs[8], varargs[9],
+                     varargs[10], varargs[11], varargs[12], varargs[13], varargs[14],
+                     varargs[15], varargs[16], varargs[17], varargs[18], varargs[19]);
+
+    return id;
+}
+
+struct wl_proxy *RA_wl_proxy_marshal_array_constructor_versioned(
+    struct wl_proxy *proxy, uint32_t opcode,
+    union wl_argument *args,
+    const struct wl_interface *iface, uint32_t version)
+{
+    static struct wl_proxy *(*fn)(struct wl_proxy *, uint32_t,
+                                  union wl_argument *, const struct wl_interface *, uint32_t) = NULL;
+    static int dlsym_called = 0;
+
+    if (!dlsym_called) {
+        fn = dlsym(RTLD_NEXT, "wl_proxy_marshal_array_constructor_versioned");
+        dlsym_called = 1;
+    }
+
+    if (!fn) {
+        return wl_proxy_marshal_array_constructor(proxy, opcode, args, iface);
+    }
+
+    return fn(proxy, opcode, args, iface, version);
+}

input/common/wayland_common_webos.h

@@ -37,4 +37,15 @@ enum webos_wl_special_keymap
 extern uint8_t webos_wl_special_keymap[webos_wl_key_size];
 extern void shutdown_webos_contexts();
 
+/* Backwards compatibility for webOS 3 */
+#define WL_CLOSURE_MAX_ARGS 20
+
+#define wl_proxy_marshal_constructor_versioned \
+    RA_wl_proxy_marshal_constructor_versioned
+
+#define wl_proxy_marshal_array_constructor_versioned \
+    RA_wl_proxy_marshal_array_constructor_versioned
+
+/* end: backwards compatibility for webOS 3 */
+
 #endif