'lua_upvalueid' returns NULL on invalid upvalue index

This commit is contained in:
Roberto Ierusalimschy 2020-10-12 14:51:28 -03:00
parent 9a89fb1c9d
commit 30528049f1
4 changed files with 33 additions and 15 deletions

View file

@ -281,25 +281,33 @@ static int db_setupvalue (lua_State *L) {
** Check whether a given upvalue from a given closure exists and
** returns its index
*/
static int checkupval (lua_State *L, int argf, int argnup) {
static void *checkupval (lua_State *L, int argf, int argnup, int *pnup) {
void *id;
int nup = (int)luaL_checkinteger(L, argnup); /* upvalue index */
luaL_checktype(L, argf, LUA_TFUNCTION); /* closure */
luaL_argcheck(L, (lua_getupvalue(L, argf, nup) != NULL), argnup,
"invalid upvalue index");
return nup;
id = lua_upvalueid(L, argf, nup);
if (pnup) {
luaL_argcheck(L, id != NULL, argnup, "invalid upvalue index");
*pnup = nup;
}
return id;
}
static int db_upvalueid (lua_State *L) {
int n = checkupval(L, 1, 2);
lua_pushlightuserdata(L, lua_upvalueid(L, 1, n));
void *id = checkupval(L, 1, 2, NULL);
if (id != NULL)
lua_pushlightuserdata(L, id);
else
luaL_pushfail(L);
return 1;
}
static int db_upvaluejoin (lua_State *L) {
int n1 = checkupval(L, 1, 2);
int n2 = checkupval(L, 3, 4);
int n1, n2;
checkupval(L, 1, 2, &n1);
checkupval(L, 3, 4, &n2);
luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
lua_upvaluejoin(L, 1, n1, 3, n2);