sol2/sol/table.hpp

// The MIT License (MIT)

// Copyright (c) 2013 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_TABLE_HPP
#define SOL_TABLE_HPP

#include "stack.hpp"
#include "lua_function.hpp"
#include <unordered_map>
#include <array>
#include <memory>
#include <cstring>

namespace sol {
namespace detail {
    template<typename T>
    T* get_ptr(T& val) {
        return std::addressof(val);
    }

    template<typename T>
    T* get_ptr(T* val) {
        return val;
    }
}
class table : virtual public reference {
private:
     std::unordered_map<std::string, std::shared_ptr<lua_func>> funcs;
public:
    table() noexcept: reference(), funcs() {}
    table(lua_State* L, int index = -1): reference(L, index), funcs() {
        type_assert(L, index, type::table);
    }

    template<typename T, typename U>
    T get(U&& key) const {
        push();
        stack::push(state(), std::forward<U>(key));
        lua_gettable(state(), -2);
        type_assert(state(), -1, type_of<T>());
        auto result = stack::pop<T>(state());
        lua_pop(state(), 1);
        return result;
    }

    template<typename T, typename U>
    table& set(T&& key, U&& value) {
        push();
        stack::push(state(), std::forward<T>(key));
        stack::push(state(), std::forward<U>(value));
        lua_settable(state(), -3);
        lua_pop(state(), 1);
        return *this;
    }

    template<typename T, typename TFx>
    table& set_function(T&& key, TFx&& fx) {
        typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type clean_fx;
       return set_isfunction_fx(std::is_function<clean_fx>(), std::forward<T>(key), std::forward<TFx>(fx));
    }

    template<typename T, typename TFx, typename TObj>
    table& set_function(T&& key, TFx&& fx, TObj&& obj) {
        return set_lvalue_fx(std::integral_constant<bool, std::is_lvalue_reference<TObj>::value || std::is_pointer<TObj>::value>(), 
            std::forward<T>(key), std::forward<TFx>(fx), std::forward<TObj>(obj));
    }

    size_t size() const {
        push();
        return lua_rawlen(state(), -1);
    }
private:

    template<typename T, typename TFx>
    table& set_isfunction_fx(std::true_type, T&& key, TFx&& fx) {
        return set_fx(std::false_type(), std::forward<T>(key), std::forward<TFx>(fx));
    }

    template<typename T, typename TFx>
    table& set_isfunction_fx(std::false_type, T&& key, TFx&& fx) {
       typedef typename std::decay<TFx>::type clean_lambda;
       typedef typename detail::function_traits<decltype(&clean_lambda::operator())>::free_function_pointer_type raw_func_t;
        typedef std::is_convertible<clean_lambda, raw_func_t> isconvertible;
       return set_isconvertible_fx(isconvertible(), std::forward<T>(key), std::forward<TFx>(fx));
    }

    template<typename T, typename TFx>
    table& set_isconvertible_fx(std::true_type, T&& key, TFx&& fx) {
        typedef typename std::decay<TFx>::type clean_lambda;
        typedef typename detail::function_traits<decltype(&clean_lambda::operator())>::free_function_pointer_type raw_func_t;
        return set_isfunction_fx(std::true_type(), std::forward<T>(key), raw_func_t(std::forward<TFx>(fx)));
    }

    template<typename T, typename TFx>
    table& set_isconvertible_fx(std::false_type, T&& key, TFx&& fx) {
       typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type clean_fx;
       std::unique_ptr<lua_func> sptr(new lambda_lua_func<clean_fx>(std::forward<TFx>(fx)));
       return set_fx(std::forward<T>(key), std::move(sptr));
    }

    template<typename T, typename TFx, typename TObj>
    table& set_lvalue_fx(std::true_type, T&& key, TFx&& fx, TObj&& obj) {
        return set_fx(std::true_type(), std::forward<T>(key), std::forward<TFx>(fx), std::forward<TObj>(obj));
    }

    template<typename T, typename TFx, typename TObj>
    table& set_lvalue_fx(std::false_type, T&& key, TFx&& fx, TObj&& obj) {
        typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type clean_fx;
        std::unique_ptr<lua_func> sptr(new explicit_lua_func<clean_fx, TObj>(std::forward<TObj>( obj ), std::forward<TFx>(fx)));
        return set_fx(std::forward<T>(key), std::move(sptr));
    }

    template<typename T, typename TFx, typename TObj>
    table& set_fx(std::true_type, T&& key, TFx&& fx, TObj&& obj) {
        typedef typename std::decay<TObj>::type decay_of_to;
        typedef typename std::decay<TFx>::type decay_of_tfx;
        const static std::size_t data_t_count = (sizeof(decay_of_tfx)+(sizeof(void*)-1)) / sizeof(void*);
        typedef std::array<void*, data_t_count> data_t;

        std::string fkey(key);
        
        // 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_of_tfx fxptr(std::forward<TFx>(fx));
        data_t fxptrdata;
        std::size_t fxptrsize = sizeof(fxptr);
        std::memcpy(std::addressof(fxptrdata[ 0 ]), std::addressof(fxptr), fxptrsize);
        void* userobjdata = static_cast<void*>(detail::get_ptr(obj));
        lua_CFunction freefunc = &static_object_lua_func<decay_of_to, TFx>::call;
        const char* freefuncname = fkey.c_str();
        const luaL_Reg funcreg[ 2 ] = {
            { freefuncname, freefunc },
            { nullptr, nullptr }
        };

        
        push();

        stack::push(state(), fxptrdata);
        stack::push(state(), userobjdata);
        luaL_setfuncs(state(), funcreg, fxptrdata.size() + 1);

        lua_pop(state(), 1);
        return *this;
    }

    template<typename T, typename TFx>
    table& set_fx(std::false_type, T&& key, TFx&& fx) {
        typedef typename std::decay<TFx>::type ptr_fx;
       std::string fkey(key);
       ptr_fx target(std::forward<TFx>(fx));
       void* userdata = reinterpret_cast<void*>(target);
       lua_CFunction freefunc = &static_lua_func<TFx>::call;
       const char* freefuncname = fkey.c_str();
       const luaL_Reg funcreg[ 2 ] = {
           { freefuncname, freefunc },
		 { nullptr, nullptr }
       };

       push();

       stack::push(state(), userdata);
       luaL_setfuncs(state(), funcreg, 1);

       lua_pop(state(), 1);
       return *this;
    }

    template<typename T>
    table& set_fx(T&& key, std::unique_ptr<lua_func> luafunc) {
        std::string fkey(key);
        auto hint = funcs.find(fkey);
        if (hint == funcs.end()) {
            std::shared_ptr<lua_func> sptr(luafunc.release());
            hint = funcs.emplace_hint(hint, fkey, std::move(sptr));
        }
        else {
            hint->second.reset(luafunc.release());
        }
        lua_func* target = hint->second.get();
        void* userdata = reinterpret_cast<void*>(target);
        lua_CFunction freefunc = &lua_func::call;
        const char* freefuncname = hint->first.c_str();
        const luaL_Reg funcreg[ 2 ] = {
            { freefuncname, freefunc },
		  { nullptr, nullptr }
        };

        push();

        stack::push(state(), userdata);
        luaL_setfuncs(state(), funcreg, 1);

        lua_pop(state(), 1);
        return *this;
    }
};
} // sol

#endif // SOL_TABLE_HPP