// Expects: Function, followed by narg arguments, on top of the stack.
// Calls pcall with traceback error handler, removes error handler.
// Error is left on top of the stack.
// Returns the error code, and the stack index at which the return values start.
inline std::tuple<int, int>
pcall_helper(lua_State * L, int narg, int nret) noexcept {
PRIMER_ASSERT(lua_gettop(L) >= (1 + narg),
"Not enough arguments on stack for pcall!");
PRIMER_ASSERT(lua_isfunction(L, -1 - narg), "Missing function for pcall!");
primer::get_error_handler(L);
lua_insert(L, -2 - narg);
const int error_handler_index = lua_absindex(L, -2 - narg);
const int result_code = lua_pcall(L, narg, nret, error_handler_index);
lua_remove(L, error_handler_index);
return std::tuple<int, int>{result_code, error_handler_index};
}
T
unsigned_to_signed(typename std::make_unsigned<T>::type x) {
using U = decltype(x);
constexpr T max = std::numeric_limits<T>::max();
constexpr T min = std::numeric_limits<T>::min();
if (x <= static_cast<U>(max)) { return static_cast<T>(x); }
if (x >= static_cast<U>(min)) { return static_cast<T>(x - min) + min; }
PRIMER_ASSERT(false, "Bad unsigned -> signed integer conversion! x = " << x);
return 0;
}
void
fcn_call(expected<T> & result, lua_State * L, int narg) {
int err_code;
int results_idx;
std::tie(err_code, results_idx) =
detail::pcall_helper(L, narg, return_helper<T>::nrets);
if (err_code != LUA_OK) {
result = primer::pop_error(L, err_code);
} else {
return_helper<T>::pop(L, results_idx, result);
}
PRIMER_ASSERT(lua_gettop(L) == (results_idx - 1),
"hmm stack discipline error");
}
// Expects: Function, followed by narg arguments, on top of the stack.
// Calls lua_resume. If an error occurs, calls the traceback error handler,
// removes error handler. Error is left on top of the stack.
// Returns the error code, and the stack index at which the return values start.
inline std::tuple<int, int>
resume_helper(lua_State * L, int narg) noexcept {
PRIMER_ASSERT(lua_gettop(L) >= (narg),
"Not enough arguments on stack for resume!");
const int result_index = lua_absindex(L, -1 - narg);
const int result_code = lua_resume(L, nullptr, narg);
if ((result_code != LUA_OK) && (result_code != LUA_YIELD)) {
primer::get_error_handler(L);
lua_insert(L, -2);
lua_call(L, 1, 1);
}
return std::tuple<int, int>{result_code, result_index};
}
