// Copyright (c) 2005 Daniel Wallin and Arvid Norberg

// 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 LUABIND_HANDLE_050420_HPP
#define LUABIND_HANDLE_050420_HPP

#include <luabind/lua_include.hpp>
#include <luabind/value_wrapper.hpp>
#include <luabind/detail/ref.hpp>

namespace luabind
{

// A reference to a Lua value. Represents an entry in the
// registry table.
class handle
{
public:
    handle();
    handle( lua_State* interpreter, int stack_index );
    handle( handle const& other );
    ~handle();

    handle& operator=( handle const& other );
    void swap( handle& other );

    void push( lua_State* interpreter ) const;

    lua_State* interpreter() const;

    void replace( lua_State* interpreter, int stack_index );

private:
    lua_State* m_interpreter;
    int m_index;
};

inline handle::handle()
        : m_interpreter( 0 )
        , m_index( LUA_NOREF )
{}

inline handle::handle( handle const& other )
        : m_interpreter( other.m_interpreter )
        , m_index( LUA_NOREF )
{
    if ( m_interpreter == 0 )
        return;
    detail::getref( m_interpreter, other.m_index );
    m_index = detail::ref( m_interpreter );
}

inline handle::handle( lua_State* interpreter, int stack_index )
        : m_interpreter( interpreter )
        , m_index( LUA_NOREF )
{
    lua_pushvalue( interpreter, stack_index );
    m_index = detail::ref( interpreter );
}

inline handle::~handle()
{
    if ( m_interpreter && m_index != LUA_NOREF )
        detail::unref( m_interpreter, m_index );
}

inline handle& handle::operator=( handle const& other )
{
    handle( other ).swap( *this );
    return *this;
}

inline void handle::swap( handle& other )
{
    std::swap( m_interpreter, other.m_interpreter );
    std::swap( m_index, other.m_index );
}

inline void handle::push( lua_State* interpreter ) const
{
    detail::getref( interpreter, m_index );
}

inline lua_State* handle::interpreter() const
{
    return m_interpreter;
}

inline void handle::replace( lua_State* interpreter, int stack_index )
{
    lua_pushvalue( interpreter, stack_index );
    lua_rawseti( interpreter, LUA_REGISTRYINDEX, m_index );
}

template<>
struct value_wrapper_traits<handle>
{
    typedef boost::mpl::true_ is_specialized;

    static lua_State* interpreter( handle const& value )
    {
        return value.interpreter();
    }

    static void unwrap( lua_State* interpreter, handle const& value )
    {
        value.push( interpreter );
    }

    static bool check( ... )
    {
        return true;
    }
};

} // namespace luabind

#endif // LUABIND_HANDLE_050420_HPP

