dub optimizations

gistfile1.cpp

// =========================================================== Return value optimization

/** Vect Vect::operator+(const Vect &v)
 * test/fixtures/pointers/Vect.h:55
 */
static int Vect_operator_add(lua_State *L) {
  try {
    Vect *self = *((Vect**)dub_checksdata(L, 1, "Vect"));
    Vect *v = *((Vect**)dub_checksdata(L, 2, "Vect"));
    dub_pushudata(L, new Vect(self->operator+(*v)), "Vect");
    return 1;
  } catch (std::exception &e) {
    lua_pushfstring(L, "operator+: %s", e.what());
  } catch (...) {
    lua_pushfstring(L, "operator+: Unknown exception");
  }
  return lua_error(L);
}

// =========================================================== No gc optimization

/** Nogc Nogc::operator+(const Nogc &v)
 * test/fixtures/memory/Nogc.h:22
 */
static int Nogc_operator_add(lua_State *L) {
  try {
    Nogc *self = *((Nogc**)dub_checksdata(L, 1, "Nogc"));
    Nogc *v = *((Nogc**)dub_checksdata(L, 2, "Nogc"));
    dub_pushfulldata<Nogc>(L, self->operator+(*v), "Nogc");
    return 1;
  } catch (std::exception &e) {
    lua_pushfstring(L, "operator+: %s", e.what());
  } catch (...) {
    lua_pushfstring(L, "operator+: Unknown exception");
  }
  return lua_error(L);
}

// =========================================================== dub_pushfulldata template

template<class T>
struct DubUserdata {
  T *ptr;
  T obj;
};

template<class T>
void dub_pushfulldata(lua_State *L, const T &obj, const char *type_name) {
  DubUserdata<T> *copy = (DubUserdata<T>*)lua_newuserdata(L, sizeof(DubUserdata<T>));
  copy->obj = obj;
  // now **copy gives back the object.
  copy->ptr = &copy->obj;

  // the userdata is now on top of the stack

  // set metatable (contains methods)
  luaL_getmetatable(L, type_name);
  lua_setmetatable(L, -2);
}