sol2/sol/stack_guard.hpp

// The MIT License (MIT) 

// Copyright (c) 2013-2016 Rapptz, ThePhD and contributors

// 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
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#ifndef SOL_STACK_GUARD_HPP
#define SOL_STACK_GUARD_HPP

#include "compatibility/version.hpp"
#include "error.hpp"
#include <functional>

namespace sol {
namespace detail {
inline void stack_fail(int, int) {
#ifndef SOL_NO_EXCEPTIONS
    throw error(detail::direct_error, "imbalanced stack after operation finish");
#else
    // Lol, what do you want, an error printout? :3c
    // There's no sane default here. The right way would be C-style abort(), and that's not acceptable, so
    // hopefully someone will register their own stack_fail thing here
#endif // No Exceptions
}
} // detail

struct stack_guard {
    lua_State* L;
    int top;
    std::function<void(int, int)> fx;

    stack_guard(lua_State* L) : stack_guard(L, lua_gettop(L)) {}
    stack_guard(lua_State* L, int top, std::function<void(int, int)> fx = detail::stack_fail) : L(L), top(top), fx(std::move(fx)) {}
    ~stack_guard() {
        int bottom = lua_gettop(L);
        if (top == bottom) {
            return;
        }
	   fx(top, bottom);
    }
};
} // sol

#endif // SOL_STACK_GUARD_HPP