sol2/sol/function.hpp
ThePhD 219d10b0b4 Thanks to LUA_MULTRET, we can have normal function call syntax with sol::function that doesn't require the user to pass the arguments in directly with .call<Return1, Return2, Return3>( ... )
function result is meant to be transient, and therefore should not be regularly storeable by the user... but there is no way to make a "and you can't have anything but a temporary to this" type, as far as I can tell.
2015-07-19 10:26:11 -04:00

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// The MIT License (MIT)
// Copyright (c) 2013-2015 Danny Y., Rapptz
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#ifndef SOL_FUNCTION_HPP
#define SOL_FUNCTION_HPP
#include "reference.hpp"
#include "tuple.hpp"
#include "stack.hpp"
#include "function_types.hpp"
#include "usertype_traits.hpp"
#include "resolve.hpp"
#include <cstdint>
#include <functional>
#include <memory>
namespace sol {
class function_result {
private:
lua_State* L;
int index;
int returncount;
template <typename T, std::size_t I>
T get(types<T>, indices<I>) const {
return stack::get<T>(L, index);
}
template <typename... Ret, std::size_t... I>
std::tuple<Ret...> get(types<Ret...>, indices<I...>) const {
auto r = std::make_tuple(stack::get<Ret>(L, index + I)...);
return r;
}
public:
function_result() = default;
function_result(lua_State* L, int index = -1, int returncount = 0): L(L), index(index), returncount(returncount) {
}
function_result(const function_result&) = default;
function_result& operator=(const function_result&) = default;
function_result(function_result&&) = default;
function_result& operator=(function_result&&) = default;
template <typename T>
operator T () const {
auto tr = tuple_types<T>();
return get(tr, tr);
}
~function_result() {
lua_pop(L, returncount);
}
};
class function : public reference {
private:
void luacall(std::ptrdiff_t argcount, std::ptrdiff_t resultcount) const {
lua_call(state(), static_cast<int>(argcount), static_cast<int>(resultcount));
}
template<std::size_t... I, typename... Ret>
std::tuple<Ret...> invoke(indices<I...>, types<Ret...>, std::ptrdiff_t n) const {
luacall(n, sizeof...(Ret));
const int nreturns = static_cast<int>(sizeof...(Ret));
const int stacksize = lua_gettop(state());
const int firstreturn = std::max(0, stacksize - nreturns) + 1;
auto r = std::make_tuple(stack::get<Ret>(state(), firstreturn + I)...);
lua_pop(state(), nreturns);
return r;
}
template<std::size_t I, typename Ret>
Ret invoke(indices<I>, types<Ret>, std::ptrdiff_t n) const {
luacall(n, 1);
return stack::pop<Ret>(state());
}
template <std::size_t I>
void invoke(indices<I>, types<void>, std::ptrdiff_t n) const {
luacall(n, 0);
}
function_result invoke(indices<>, types<>, std::ptrdiff_t n) const {
const int stacksize = lua_gettop(state());
const int firstreturn = std::max(0, stacksize - static_cast<int>(n) - 1);
luacall(n, LUA_MULTRET);
const int poststacksize = lua_gettop(state());
const int returncount = poststacksize - firstreturn;
return function_result(state(), firstreturn + 1, returncount);
}
public:
function() = default;
function(lua_State* L, int index = -1): reference(L, index) {
type_assert(L, index, type::function);
}
function(const function&) = default;
function& operator=(const function&) = default;
template<typename... Args>
function_result operator()(Args&&... args) const {
return call<>(std::forward<Args>(args)...);
}
template<typename... Ret, typename... Args>
ReturnType<Ret...> operator()(types<Ret...>, Args&&... args) const {
return call<Ret...>(std::forward<Args>(args)...);
}
template<typename... Ret, typename... Args>
auto call(Args&&... args) const -> decltype(invoke(types<Ret...>(), types<Ret...>(), 0)) {
push();
int pushcount = stack::push_args(state(), std::forward<Args>(args)...);
auto tr = types<Ret...>();
return invoke(tr, tr, pushcount);
}
};
namespace stack {
template<typename... Sigs>
struct pusher<function_sig_t<Sigs...>> {
template<typename R, typename... Args, typename Fx, typename = typename std::result_of<Fx(Args...)>::type>
static void set_memfx(types<R(Args...)> t, lua_State* L, Fx&& fx) {
typedef Decay<Unwrap<Fx>> raw_fx_t;
typedef R(* fx_ptr_t)(Args...);
typedef std::is_convertible<raw_fx_t, fx_ptr_t> is_convertible;
set_isconvertible_fx(is_convertible(), t, L, std::forward<Fx>(fx));
}
template<typename Fx>
static void set_memfx(types<>, lua_State* L, Fx&& fx) {
typedef Unqualified<Unwrap<Fx>> fx_t;
typedef decltype(&fx_t::operator()) Sig;
set_memfx(types<function_signature_t<Sig>>(), L, std::forward<Fx>(fx));
}
template<typename... Args, typename R>
static void set(lua_State* L, R fxptr(Args...)){
set_fx(std::false_type(), L, fxptr);
}
template<typename Sig>
static void set(lua_State* L, Sig* fxptr){
set_fx(std::false_type(), L, fxptr);
}
template<typename... Args, typename R, typename C, typename T>
static void set(lua_State* L, R (C::*memfxptr)(Args...), T&& obj) {
typedef Bool<is_specialization_of<T, std::reference_wrapper>::value || std::is_pointer<T>::value> is_reference;
set_reference_fx(is_reference(), L, memfxptr, std::forward<T>(obj));
}
template<typename Sig, typename C, typename T>
static void set(lua_State* L, Sig C::* memfxptr, T&& obj) {
typedef Bool<is_specialization_of<T, std::reference_wrapper>::value || std::is_pointer<T>::value> is_reference;
set_reference_fx(is_reference(), L, memfxptr, std::forward<T>(obj));
}
template<typename... Sig, typename Fx>
static void set(lua_State* L, Fx&& fx) {
set_memfx(types<Sig...>(), L, std::forward<Fx>(fx));
}
template<typename Fx, typename R, typename... Args>
static void set_isconvertible_fx(std::true_type, types<R(Args...)>, lua_State* L, Fx&& fx) {
typedef R(* fx_ptr_t)(Args...);
fx_ptr_t fxptr = unwrapper(std::forward<Fx>(fx));
set(L, fxptr);
}
template<typename Fx, typename R, typename... Args>
static void set_isconvertible_fx(std::false_type, types<R(Args...)>, lua_State* L, Fx&& fx) {
typedef Decay<Unwrap<Fx>> fx_t;
std::unique_ptr<base_function> sptr(new functor_function<fx_t>(std::forward<Fx>(fx)));
set_fx<Fx>(L, std::move(sptr));
}
template<typename Fx, typename T>
static void set_reference_fx(std::true_type, lua_State* L, Fx&& fx, T&& obj) {
set_fx(std::true_type(), L, std::forward<Fx>(fx), std::forward<T>(obj));
}
template<typename Fx, typename T>
static void set_reference_fx(std::false_type, lua_State* L, Fx&& fx, T&& obj) {
typedef typename std::remove_pointer<Decay<Fx>>::type clean_fx;
std::unique_ptr<base_function> sptr(new member_function<clean_fx, T>(std::forward<T>(obj), std::forward<Fx>(fx)));
return set_fx<Fx>(L, std::move(sptr));
}
template<typename Fx, typename T>
static void set_fx(std::true_type, lua_State* L, Fx&& fx, T&& obj) {
// Layout:
// idx 1...n: verbatim data of member function pointer
// idx n + 1: is the object's void pointer
// We don't need to store the size, because the other side is templated
// with the same member function pointer type
Decay<Fx> memfxptr(std::forward<Fx>(fx));
auto userptr = sol::detail::get_ptr(obj);
void* userobjdata = static_cast<void*>(userptr);
lua_CFunction freefunc = &static_member_function<Decay<decltype(*userptr)>, Fx>::call;
int upvalues = stack::detail::push_as_upvalues(L, memfxptr);
upvalues += stack::push(L, userobjdata);
stack::push(L, freefunc, upvalues);
}
template<typename Fx>
static void set_fx(std::false_type, lua_State* L, Fx&& fx) {
Decay<Fx> target(std::forward<Fx>(fx));
lua_CFunction freefunc = &static_function<Fx>::call;
int upvalues = stack::detail::push_as_upvalues(L, target);
stack::push(L, freefunc, upvalues);
}
template<typename Fx>
static void set_fx(lua_State* L, std::unique_ptr<base_function> luafunc) {
auto&& metakey = usertype_traits<Unqualified<Fx>>::metatable;
const char* metatablename = std::addressof(metakey[0]);
base_function* target = luafunc.release();
void* userdata = reinterpret_cast<void*>(target);
lua_CFunction freefunc = &base_function::call;
if(luaL_newmetatable(L, metatablename) == 1) {
lua_pushstring(L, "__gc");
stack::push(L, &base_function::gc);
lua_settable(L, -3);
lua_pop(L, 1);
}
stack::detail::push_userdata<void*>(L, metatablename, userdata);
stack::push(L, freefunc, 1);
}
template<typename... Args>
static int push(lua_State* L, Args&&... args) {
// Set will always place one thing (function) on the stack
set(L, std::forward<Args>(args)...);
return 1;
}
};
template<typename Signature>
struct pusher<std::function<Signature>> {
static int push(lua_State* L, std::function<Signature> fx) {
return pusher<function_t>{}.push(L, std::move(fx));
}
};
template<typename Signature>
struct getter<std::function<Signature>> {
typedef function_traits<Signature> fx_t;
typedef typename fx_t::args_type args_t;
typedef typename tuple_types<typename fx_t::return_type>::type ret_t;
template<typename... FxArgs, typename... Ret>
static std::function<Signature> get_std_func(types<FxArgs...>, types<Ret...>, lua_State* L, int index = -1) {
typedef typename function_traits<Signature>::return_type return_t;
sol::function f(L, index);
auto fx = [f, L, index](FxArgs&&... args) -> return_t {
return f(types<Ret...>(), std::forward<FxArgs>(args)...);
};
return std::move(fx);
}
template<typename... FxArgs>
static std::function<Signature> get_std_func(types<FxArgs...>, types<void>, lua_State* L, int index = -1) {
sol::function f(L, index);
auto fx = [f, L, index](FxArgs&&... args) -> void {
f(std::forward<FxArgs>(args)...);
};
return std::move(fx);
}
template<typename... FxArgs>
static std::function<Signature> get_std_func(types<FxArgs...> t, types<>, lua_State* L, int index = -1) {
return get_std_func(std::move(t), types<void>(), L, index);
}
static std::function<Signature> get(lua_State* L, int index) {
return get_std_func(args_t(), ret_t(), L, index);
}
};
} // stack
} // sol
#endif // SOL_FUNCTION_HPP