netradiant clang issue #3 file 2

/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   GtkRadiant is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined( INCLUDED_GENERIC_CLOSURE_H )
#define INCLUDED_GENERIC_CLOSURE_H

/// \file
/// \brief Type-safe techniques for binding the first argument of an opaque callback.

#include <cstddef>
#include "functional.h"

namespace detail {

    template<typename Thunk_>
    class CallbackBase {
        void *m_environment;
        Thunk_ m_thunk;
    public:
        typedef Thunk_ Thunk;

        CallbackBase(void *environment, Thunk function) : m_environment(environment), m_thunk(function) {
        }

        void *getEnvironment() const {
            return m_environment;
        }

        Thunk getThunk() const {
            return m_thunk;
        }
    };

    template<typename Thunk>
    inline bool operator==(const CallbackBase<Thunk> &self, const CallbackBase<Thunk> &other) {
        return self.getEnvironment() == other.getEnvironment() && self.getThunk() == other.getThunk();
    }

    template<typename Thunk>
    inline bool operator!=(const CallbackBase<Thunk> &self, const CallbackBase<Thunk> &other) {
        return !(self == other);
    }

    template<typename Thunk>
    inline bool operator<(const CallbackBase<Thunk> &self, const CallbackBase<Thunk> &other) {
        return self.getEnvironment() < other.getEnvironment() ||
               (!(other.getEnvironment() < self.getEnvironment()) && self.getThunk() < other.getThunk());
    }

}

namespace detail {

    template<class Type>
    struct ConvertFromOpaque {
    };

    // reference

    template<class T>
    inline const void *convertToOpaque(const T &t) {
        return &t;
    }

    template<class T>
    struct ConvertFromOpaque<const T &> {
        static T const &apply(void *p) {
            return *static_cast<const T *>(p);
        }
    };

    template<class T>
    inline void *convertToOpaque(T &t) {
        return &t;
    }

    template<class T>
    struct ConvertFromOpaque<T &> {
        static T &apply(void *p) {
            return *static_cast<T *>( p );
        }
    };

    // pointer

    template<class T, class U = typename std::enable_if<!std::is_function<T>::value>::type>
    inline const void *convertToOpaque(const T *t) {
        return t;
    }

    template<class T>
    struct ConvertFromOpaque<const T *> {
        static const T *apply(void *p) {
            return static_cast<const T *>(p);
        }
    };

    template<class T, class U = typename std::enable_if<!std::is_function<T>::value>::type>
    template<class T>
    inline void *convertToOpaque(T *t) {
        return t;
    }

    template<class T>
    struct ConvertFromOpaque<T *> {
        static T *apply(void *p) {
            return static_cast<T *>(p);
        }
    };

    // function pointer

    template<class R, class... Ts>
    inline const void *convertToOpaque(R(*const &t)(Ts...)) {
        return &t;
    }

    template<class R, class... Ts>
    struct ConvertFromOpaque<R(*const &)(Ts...)> {
        using Type = R(*)(Ts...);

        static Type const &apply(void *p) {
            return *static_cast<Type *>(p);
        }
    };

    template<class R, class... Ts>
    inline void *convertToOpaque(R(*&t)(Ts...)) {
        return &t;
    }

    template<class R, class... Ts>
    struct ConvertFromOpaque<R(*&)(Ts...)> {
        using Type = R(*)(Ts...);

        static Type &apply(void *p) {
            return *static_cast<Type *>(p);
        }
    };

    template<class Caller, class F>
    class BindFirstOpaqueN;

    template<class Caller, class R, class FirstBound, class... Ts>
    class BindFirstOpaqueN<Caller, R(FirstBound, Ts...)> {
        FirstBound firstBound;
    public:
        explicit BindFirstOpaqueN(FirstBound firstBound) : firstBound(firstBound) {
        }

        R operator()(Ts... args) const {
            return Caller::call(firstBound, args...);
        }

        FirstBound getBound() const {
            return firstBound;
        }

        static R thunk(void *environment, Ts... args) {
            return thunk_(detail::ConvertFromOpaque<FirstBound>::apply(environment), args...);
        }

        static R thunk_(FirstBound environment, Ts... args) {
            return Caller::call(environment, args...);
        }

        void *getEnvironment() const {
            return const_cast<void *>(detail::convertToOpaque(firstBound));
        }
    };

}

template<class Caller>
using BindFirstOpaque = detail::BindFirstOpaqueN<Caller, get_func<Caller>>;

/// \brief Combines a void pointer with a pointer to a function which operates on a void pointer.
///
/// Use with the callback constructors MemberCaller0, ConstMemberCaller0, ReferenceCaller0, ConstReferenceCaller0, PointerCaller0, ConstPointerCaller0 and FreeCaller0.
template<class F>
class Callback;

template<class R, class... Ts>
class Callback<R(Ts...)> : public detail::CallbackBase<R(*)(void *, Ts...)> {
    using Base = detail::CallbackBase<R (*)(void *, Ts...)>;

    static R nullThunk(void *, Ts...) {
    }

public:
    using func = R(Ts...);

    Callback() : Base(0, nullThunk) {
    }

    template<typename Caller>
    Callback(const BindFirstOpaque<Caller> &caller) : Base(caller.getEnvironment(), BindFirstOpaque<Caller>::thunk) {
    }

    Callback(void *environment, typename Base::Thunk function) : Base(environment, function) {
    }

    R operator()(Ts... args) const {
        return Base::getThunk()(Base::getEnvironment(), args...);
    }
};

namespace detail {
    template<class F>
    struct Arglist;

    template<class R, class Head, class... Ts>
    struct Arglist<R(Head, Ts...)> {
        using type = R(Head, Ts...);

        template <class Unshift>
        using unshift = Arglist<R(Unshift, Head, Ts...)>;

        using shift = Arglist<R(Ts...)>;
    };

    template<class R, class... Ts>
    struct Arglist<R(Ts...)> {
        using type = R(Ts...);

        template <class Unshift>
        using unshift = Arglist<R(Unshift, Ts...)>;
    };

    template<class F>
    using ArgShift = typename detail::Arglist<F>::shift::type;

    template<class F, class T>
    using ArgUnshift = typename detail::Arglist<F>::template unshift<T>::type;
}

template<typename Caller>
inline Callback<detail::ArgShift<get_func<Caller>>> makeCallback(const Caller &caller, get_argument<Caller, 0> callee) {
    return BindFirstOpaque<Caller>(callee);
}

template<class Caller, class F>
class CallerShiftFirst;

template<class Caller, class R, class FirstArgument, class... Ts>
class CallerShiftFirst<Caller, R(FirstArgument, Ts...)> {
public:
    using func = R(FirstArgument, Ts...);

    static R call(FirstArgument, Ts... args) {
        return Caller::call(args...);
    }
};

template<typename Caller>
inline Callback<get_func<Caller>> makeStatelessCallback(const Caller &caller) {
    return makeCallback(CallerShiftFirst<Caller, detail::ArgUnshift<get_func<Caller>, void *>>(), nullptr);
}

/// \brief Forms a Callback from a non-const Environment reference and a non-const Environment member-function.
template<class Environment, class F, MemberFunction<Environment, F> member>
using MemberCaller = BindFirstOpaque<Member<Environment, F, member>>;

/// \brief  Constructs a Callback1 from a non-const \p functor
///
/// \param Functor Must define \c first_argument_type and \c operator()(first_argument_type).
template<typename Functor>
inline Callback<get_func<Functor>> makeCallback(Functor &functor) {
    return MemberCaller<Functor, get_func<Functor>, &Functor::operator()>(functor);
}

/// \brief Forms a Callback from a const Environment reference and a const Environment member-function.
template<class Environment, class F, ConstMemberFunction<Environment, F> member>
using ConstMemberCaller = BindFirstOpaque<ConstMember<Environment, F, member>>;

/// \brief  Constructs a Callback1 from a const \p functor
///
/// \param Functor Must define \c first_argument_type and const \c operator()(first_argument_type).
template<typename Functor>
inline Callback<get_func<Functor>> makeCallback(const Functor &functor) {
    return ConstMemberCaller<Functor, get_func<Functor>, &Functor::operator()>(functor);
}

/// \brief Forms a Callback from a non-const Environment reference and a free function which operates on a non-const Environment reference.
template<class Environment, class F, detail::ArgUnshift<F, Environment &> *func>
using ReferenceCaller = BindFirstOpaque<Function<detail::ArgUnshift<F, Environment &>, func>>;

/// \brief Forms a Callback from a const Environment reference and a free function which operates on a const Environment reference.
template<class Environment, class F, detail::ArgUnshift<F, const Environment &> *func>
using ConstReferenceCaller = BindFirstOpaque<Function<detail::ArgUnshift<F, const Environment &>, func>>;

/// \brief Forms a Callback from a non-const Environment pointer and a free function which operates on a non-const Environment pointer.
template<class Environment, class F, detail::ArgUnshift<F, Environment *> *func>
using PointerCaller = BindFirstOpaque<Function<detail::ArgUnshift<F, Environment *>, func>>;

/// \brief Forms a Callback from a const Environment pointer and a free function which operates on a const Environment pointer.
template<class Environment, class F, detail::ArgUnshift<F, const Environment *> *func>
using ConstPointerCaller = BindFirstOpaque<Function<detail::ArgUnshift<F, const Environment *>, func>>;

namespace detail {
    template<class Caller, class F>
    class FreeCaller : public BindFirstOpaque<CallerShiftFirst<Caller, detail::ArgUnshift<F, void *>>> {
    public:
        FreeCaller() : BindFirstOpaque<CallerShiftFirst<Caller, detail::ArgUnshift<F, void *>>>(nullptr) {
        }
    };

    template<class F>
    struct FreeCallerWrapper;

    template<class R, class... Ts>
    struct FreeCallerWrapper<R(Ts...)> {
        using func = R(void *, Ts...);

        static R call(void *f, Ts... args) {
            // ideally, we'd get the implementation of the function type directly. Instead, it's passed in
            return reinterpret_cast<R(*)(Ts...)>(f)(args...);
        }
    };
}

/// \brief Forms a Callback from a free function
template<class F, F *func>
using FreeCaller = detail::FreeCaller<Function<F, func>, F>;

template<class R, class... Ts>
inline Callback<R(Ts...)> makeCallbackF(R(*func)(Ts...)) {
    void *pVoid = reinterpret_cast<void *>(func);
    return BindFirstOpaque<detail::FreeCallerWrapper<R(Ts...)>>(pVoid);
}

#endif