sol2/sol/proxy.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
// 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_PROXY_HPP
#define SOL_PROXY_HPP

#include "traits.hpp"
#include "object.hpp"
#include "function.hpp"
#include "protected_function.hpp"
#include "proxy_base.hpp"

namespace sol {
template<typename Table, typename Key>
struct proxy : public proxy_base<proxy<Table, Key>> {
private:
    typedef meta::If<meta::is_specialization_of<Key, std::tuple>, Key, std::tuple<meta::If<std::is_array<meta::Unqualified<Key>>, Key&, meta::Unqualified<Key>>>> key_type;

    template<typename T, std::size_t... I>
    decltype(auto) tuple_get(std::index_sequence<I...>) const {
        return tbl.template traverse_get<T>( std::get<I>(key)... );
    }

    template<std::size_t... I, typename T>
    void tuple_set(std::index_sequence<I...>, T&& value) const {
        tbl.traverse_set( std::get<I>(key)..., std::forward<T>(value) );
    }

public:
    Table tbl;
    key_type key;

    template<typename T>
    proxy(Table table, T&& key) : tbl(table), key(std::forward<T>(key)) {}

    template<typename T>
    proxy& set(T&& item) {
        tuple_set( std::make_index_sequence<std::tuple_size<meta::Unqualified<key_type>>::value>(), std::forward<T>(item) );
        return *this;
    }

    template<typename... Args>
    proxy& set_function(Args&&... args) {
        tbl.set_function(key, std::forward<Args>(args)...);
        return *this;
    }

    template<typename U, meta::EnableIf<meta::Function<meta::Unqualified<U>>> = 0>
    proxy& operator=(U&& other) {
        return set_function(std::forward<U>(other));
    }

    template<typename U, meta::DisableIf<meta::Function<meta::Unqualified<U>>> = 0>
    proxy& operator=(U&& other) {
        return set(std::forward<U>(other));
    }

    template<typename T>
    decltype(auto) get() const {
        return tuple_get<T>( std::make_index_sequence<std::tuple_size<meta::Unqualified<key_type>>::value>() );
    }

    template <typename K>
    decltype(auto) operator[](K&& k) const {
        auto keys = meta::tuplefy(key, std::forward<K>(k));
        return proxy<Table, decltype(keys)>(tbl, std::move(keys));
    }

    template<typename... Ret, typename... Args>
    decltype(auto) call(Args&&... args) {
        return get<function>().template call<Ret...>(std::forward<Args>(args)...);
    }

    template<typename... Args>
    decltype(auto) operator()(Args&&... args) {
        return call<>(std::forward<Args>(args)...);
    }

    bool valid () const {
        auto p = stack::probe_get_field<std::is_same<meta::Unqualified<Table>, global_table>::value>(tbl.lua_state(), key);
	   lua_pop(tbl.lua_state(), p.levels);
	   return p;
    }
};

template<typename Table, typename Key, typename T>
inline bool operator==(T&& left, const proxy<Table, Key>& right) {
    return left == right.template get<std::decay_t<T>>();
}

template<typename Table, typename Key, typename T>
inline bool operator==(const proxy<Table, Key>& right, T&& left) {
    return right.template get<std::decay_t<T>>() == left;
}

template<typename Table, typename Key, typename T>
inline bool operator!=(T&& left, const proxy<Table, Key>& right) {
    return right.template get<std::decay_t<T>>() != left;
}

template<typename Table, typename Key, typename T>
inline bool operator!=(const proxy<Table, Key>& right, T&& left) {
    return right.template get<std::decay_t<T>>() != left;
}

template<typename Table, typename Key>
inline bool operator==(nil_t, const proxy<Table, Key>& right) {
    return !right.valid();
}

template<typename Table, typename Key>
inline bool operator==(const proxy<Table, Key>& right, nil_t) {
    return !right.valid();
}

template<typename Table, typename Key>
inline bool operator!=(nil_t, const proxy<Table, Key>& right) {
    return right.valid();
}

template<typename Table, typename Key>
inline bool operator!=(const proxy<Table, Key>& right, nil_t) {
    return right.valid();
}

namespace stack {
template <typename Table, typename Key>
struct pusher<proxy<Table, Key>> {
    static int push (lua_State*, const proxy<Table, Key>& p) {
	   sol::reference r = p;
	   r.push();
        return 1;
    }
};
} // stack
} // sol

#endif // SOL_PROXY_HPP