[Feature] Add better method to check lua userdata types

diff --git a/src/lua/lua_common.c b/src/lua/lua_common.c
index e85f82d1adfd6631899cf7571f65274f053cbbf8..63aab5830cbe80ec58cd671bea4d8828d66568ca 100644 (file)
--- a/src/lua/lua_common.c
+++ b/src/lua/lua_common.c
@@ -849,24 +849,30 @@ rspamd_lua_parse_table_arguments (lua_State *L, gint pos,
        return TRUE;
 }
 
-gint
-rspamd_lua_traceback (lua_State *L)
+static void
+rspamd_lua_traceback_string (lua_State *L, GString *s)
 {
-       lua_Debug d;
-       GString *tb;
-       const gchar *msg = lua_tostring (L, 1);
        gint i = 1;
-
-       tb = g_string_sized_new (100);
-       g_string_append_printf (tb, "%s; trace:", msg);
+       lua_Debug d;
 
        while (lua_getstack (L, i++, &d)) {
                lua_getinfo (L, "nSl", &d);
-               g_string_append_printf (tb, " [%d]:{%s:%d - %s [%s]};",
+               g_string_append_printf (s, " [%d]:{%s:%d - %s [%s]};",
                                i - 1, d.short_src, d.currentline,
                                (d.name ? d.name : "<unknown>"), d.what);
        }
+}
+
+gint
+rspamd_lua_traceback (lua_State *L)
+{
+
+       GString *tb;
+       const gchar *msg = lua_tostring (L, 1);
 
+       tb = g_string_sized_new (100);
+       g_string_append_printf (tb, "%s; trace:", msg);
+       rspamd_lua_traceback_string (L, tb);
        lua_pushlightuserdata (L, tb);
 
        return 1;
@@ -985,3 +991,58 @@ lua_push_internet_address_list (lua_State *L, InternetAddressList *addrs)
        }
 #endif
 }
+
+
+void *
+rspamd_lua_check_udata (lua_State *L, gint pos, const gchar *classname)
+{
+       void *p = lua_touserdata (L, pos);
+       GString *err_msg;
+
+       if (p == NULL) {
+               err_msg = g_string_sized_new (100);
+               rspamd_printf_gstring (err_msg, "expected %s at %d, but got %s; trace: ",
+                               classname, pos, lua_typename (L, lua_type (L, pos)));
+               rspamd_lua_traceback_string (L, err_msg);
+               msg_err ("lua typecheck error: %v", err_msg);
+               g_string_free (err_msg, TRUE);
+       }
+       else {
+               /* Match class */
+               if (lua_getmetatable (L, pos)) {
+                       luaL_getmetatable (L, classname);
+
+                       if (!lua_rawequal (L, -1, -2)) {
+                               p = NULL;
+                               lua_pushstring (L, "__index");
+                               lua_gettable (L, -3);
+                               lua_pushstring (L, "class");
+                               lua_gettable (L, -2);
+
+                               err_msg = g_string_sized_new (100);
+                               rspamd_printf_gstring (err_msg, "expected %s at %d, but userdata has "
+                                               "classname: %s; trace: ",
+                                               classname, pos, lua_tostring (L, -1));
+                               rspamd_lua_traceback_string (L, err_msg);
+                               msg_err ("lua typecheck error: %v", err_msg);
+                               g_string_free (err_msg, TRUE);
+
+                               lua_pop (L, 2); /* __index -> classname */
+                       }
+
+                       lua_pop (L, 2);
+               }
+               else {
+                       p = NULL;
+                       err_msg = g_string_sized_new (100);
+                       rspamd_printf_gstring (err_msg, "expected %s at %d, but userdata has "
+                                       "no metatable; trace: ",
+                                       classname, pos);
+                       rspamd_lua_traceback_string (L, err_msg);
+                       msg_err ("lua typecheck error: %v", err_msg);
+                       g_string_free (err_msg, TRUE);
+               }
+       }
+
+       return p;
+}

diff --git a/src/lua/lua_common.h b/src/lua/lua_common.h
index 73be9e0c51508ca094bfc14e0c0ded2bcccd73f1..63039533c8e7d27049ed3251d75089f33c64e9bd 100644 (file)
--- a/src/lua/lua_common.h
+++ b/src/lua/lua_common.h
@@ -346,5 +346,14 @@ gboolean lua_push_internet_address (lua_State *L, InternetAddress *ia);
  */
 gsize lua_logger_out_type (lua_State *L, gint pos, gchar *outbuf,
                gsize len);
+
+/**
+ * Safely checks userdata to match specified class
+ * @param L
+ * @param pos
+ * @param classname
+ */
+void *rspamd_lua_check_udata (lua_State *L, gint pos, const gchar *classname);
+
 #endif /* WITH_LUA */
 #endif /* RSPAMD_LUA_H */