sol2/sol/lua_function.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_LUA_FUNC_HPP
#define SOL_LUA_FUNC_HPP

#include "functional.hpp"
#include "stack.hpp"

namespace sol {
namespace detail {

	struct lua_func {
		virtual int operator () ( lua_State* L ) {
			throw sol_error( "Failure to call specialized wrapped C++ function from lua" );
		}

		virtual ~lua_func( ) {};
	};

	template <typename TFx>
	struct lambda_lua_func : public lua_func {
		typedef decltype( &TFx::operator() ) fx_t;
		typedef function_traits<fx_t> fx_traits;
		TFx fx;

		template <typename... TFxn>
		lambda_lua_func( TFxn&&... fxn ) : fx( std::forward<TFxn>( fxn )... ) {

		}

		virtual int operator () ( lua_State* L ) override {
			return ( *this )( tuple_types<fx_traits::return_t>( ), fx_traits::args_t( ), L );
		}

		template <typename... Tn>
		int operator()( types<void>, types<Tn...> t, lua_State* L ) {
			auto r = stack::pop_call( L, fx, t );
			return 0;
		}

		template <typename... TRn, typename... Tn>
		int operator()( types<TRn...>, types<Tn...> t, lua_State* L ) {
			auto r = stack::pop_call( L, fx, t );
			stack::push( L, r );
			return sizeof...( TRn );
		}
	};

	template <typename TFx, typename T = TFx, bool is_member_pointer = std::is_member_function_pointer<TFx>::value>
	struct explicit_lua_func : public lua_func {
		typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type fx_t;
		typedef function_traits<fx_t> fx_traits;
		TFx fx;

		template <typename... TFxn>
		explicit_lua_func( TFxn&&... fxn ) : fx( std::forward<TFxn>( fxn )... ) {

		}

		virtual int operator () ( lua_State* L ) override {
			return ( *this )( tuple_types<fx_traits::return_t>( ), fx_traits::args_t( ), L );
		}

		template <typename... Tn>
		int operator () ( types<void>, types<Tn...> t, lua_State* L ) {
			auto r = stack::pop_call( L, fx, t );
			return 0;
		}

		template <typename... TRn, typename... Tn>
		int operator () ( types<TRn...>, types<Tn...> t, lua_State* L ) {
			auto r = stack::pop_call( L, fx, t );
			stack::push( L, r );
			return sizeof...( TRn );
		}
	};

	template <typename TFx, typename T>
	struct explicit_lua_func<TFx, T, true> : public lua_func {
		typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type fx_t;
		typedef function_traits<fx_t> fx_traits;
		T* member;
		TFx fx;
		
		template <typename... TFxn>
		explicit_lua_func( T* m, TFxn&&... fxn ) : member(m), fx( std::forward<TFxn>( fxn )... ) {

		}

		virtual int operator () ( lua_State* L ) override {
			return ( *this )( tuple_types<fx_traits::return_t>( ), fx_traits::args_t( ), L );
		}

		template <typename... Tn>
		int operator () ( types<void>, types<Tn...>, lua_State* L ) {
			auto r = stack::pop_call( L, fx, t );
			return 0;
		}

		template <typename... TRn, typename... Tn>
		int operator () ( types<TRn...>, types<Tn...> t, lua_State* L ) {
			auto r = stack::pop_call( L, fx, t );
			stack::push( L, r );
			return sizeof...( TRn );
		}
	};


	int lua_cfun( lua_State* L ) {
		void* bridgedata = lua_touserdata( L, lua_upvalueindex( 1 ) );
		auto* fx = static_cast<lua_func*>( bridgedata );
		int r = fx->operator()( L );
		return r;
	}

} // detail
} // sol

#endif // SOL_LUA_FUNC_HPP