/*
    ====================================================================
    A Smart Pointer to IMPLementation (i.e. Smart PIMPL or just SPIMPL).
    ====================================================================

    Version: 1.1

    Latest version:
        https://github.com/oliora/samples/blob/master/spimpl.h
    Rationale and description:
        http://oliora.github.io/2015/12/29/pimpl-and-rule-of-zero.html

    Copyright (c) 2015 Andrey Upadyshev (oliora@gmail.com)

    Distributed under the Boost Software License, Version 1.0.
    See http://www.boost.org/LICENSE_1_0.txt

    Changes history
    ---------------
    v1.1:
        - auto_ptr support is disabled by default for C++17 compatibility
    v1.0:
        - Released
 */

#ifndef SPIMPL_H_
#define SPIMPL_H_

#include <cassert>
#include <memory>
#include <type_traits>

#if defined _MSC_VER && _MSC_VER < 1900 // MS Visual Studio before VS2015
#define SPIMPL_NO_CPP11_NOEXCEPT
#define SPIMPL_NO_CPP11_CONSTEXPR
#define SPIMPL_NO_CPP11_DEFAULT_MOVE_SPEC_FUNC
#endif

#if !defined SPIMPL_NO_CPP11_NOEXCEPT
#define SPIMPL_NOEXCEPT noexcept
#else
#define SPIMPL_NOEXCEPT
#endif

#if !defined SPIMPL_NO_CPP11_CONSTEXPR
#define SPIMPL_CONSTEXPR constexpr
#else
#define SPIMPL_CONSTEXPR
#endif

// define SPIMPL_HAS_AUTO_PTR to enable constructor and assignment operator that accept
// std::auto_ptr
// TODO: auto detect std::auto_ptr support


namespace spimpl {
namespace details {
template <class T>
T *default_copy(T *src)
{
    static_assert(sizeof(T) > 0, "default_copy cannot copy incomplete type");
    static_assert(!std::is_void<T>::value, "default_copy cannot copy incomplete type");
    return new T(*src);
}

template <class T>
void default_delete(T *p) SPIMPL_NOEXCEPT
{
    static_assert(sizeof(T) > 0, "default_delete cannot delete incomplete type");
    static_assert(!std::is_void<T>::value, "default_delete cannot delete incomplete type");
    delete p;
}

template <class T>
struct default_deleter {
    using type = void (*)(T *);
};

template <class T>
using default_deleter_t = typename default_deleter<T>::type;

template <class T>
struct default_copier {
    using type = T *(*)(T *);
};

template <class T>
using default_copier_t = typename default_copier<T>::type;

template <class T, class D, class C>
struct is_default_manageable
    : public std::integral_constant<bool, std::is_same<D, default_deleter_t<T> >::value
                                              && std::is_same<C, default_copier_t<T> >::value> {
};
}


template <class T, class Deleter = details::default_deleter_t<T>,
          class Copier = details::default_copier_t<T> >
class impl_ptr {
private:
    static_assert(!std::is_array<T>::value,
                  "impl_ptr specialization for arrays is not implemented");
    struct dummy_t_ {
        int dummy__;
    };

public:
    using pointer = T *;
    using element_type = T;
    using copier_type = typename std::decay<Copier>::type;
    using deleter_type = typename std::decay<Deleter>::type;
    using unique_ptr_type = std::unique_ptr<T, deleter_type>;
    using is_default_manageable = details::is_default_manageable<T, deleter_type, copier_type>;

    SPIMPL_CONSTEXPR impl_ptr() SPIMPL_NOEXCEPT : ptr_(nullptr, deleter_type{}),
                                                  copier_(copier_type{})
    {
    }

    SPIMPL_CONSTEXPR impl_ptr(std::nullptr_t) SPIMPL_NOEXCEPT : impl_ptr() {}

    template <class D, class C>
    impl_ptr(pointer p, D &&d, C &&c,
             typename std::enable_if<std::is_convertible<D, deleter_type>::value
                                         && std::is_convertible<C, copier_type>::value,
                                     dummy_t_>::type
             = dummy_t_()) SPIMPL_NOEXCEPT : ptr_(std::move(p), std::forward<D>(d)),
                                             copier_(std::forward<C>(c))
    {
    }

    template <class U>
    impl_ptr(U *u, typename std::enable_if<std::is_convertible<U *, pointer>::value
                                               && is_default_manageable::value,
                                           dummy_t_>::type
                   = dummy_t_()) SPIMPL_NOEXCEPT
        : impl_ptr(u, &details::default_delete<T>, &details::default_copy<T>)
    {
    }

    impl_ptr(const impl_ptr &r) : impl_ptr(r.clone()) {}

#ifndef SPIMPL_NO_CPP11_DEFAULT_MOVE_SPEC_FUNC
    impl_ptr(impl_ptr &&r) SPIMPL_NOEXCEPT = default;
#else
    impl_ptr(impl_ptr &&r) SPIMPL_NOEXCEPT : ptr_(std::move(r.ptr_)), copier_(std::move(r.copier_))
    {
    }
#endif

#ifdef SPIMPL_HAS_AUTO_PTR
    template <class U>
    impl_ptr(std::auto_ptr<U> &&u, typename std::enable_if<std::is_convertible<U *, pointer>::value
                                                               && is_default_manageable::value,
                                                           dummy_t_>::type
                                   = dummy_t_()) SPIMPL_NOEXCEPT
        : ptr_(u.release(), &details::default_delete<T>),
          copier_(&details::default_copy<T>)
    {
    }
#endif

    template <class U>
    impl_ptr(std::unique_ptr<U> &&u,
             typename std::enable_if<std::is_convertible<U *, pointer>::value
                                         && is_default_manageable::value,
                                     dummy_t_>::type
             = dummy_t_()) SPIMPL_NOEXCEPT : ptr_(u.release(), &details::default_delete<T>),
                                             copier_(&details::default_copy<T>)
    {
    }

    template <class U, class D, class C>
    impl_ptr(std::unique_ptr<U, D> &&u, C &&c,
             typename std::enable_if<std::is_convertible<U *, pointer>::value
                                         && std::is_convertible<D, deleter_type>::value
                                         && std::is_convertible<C, copier_type>::value,
                                     dummy_t_>::type
             = dummy_t_()) SPIMPL_NOEXCEPT : ptr_(std::move(u)),
                                             copier_(std::forward<C>(c))
    {
    }

    template <class U, class D, class C>
    impl_ptr(impl_ptr<U, D, C> &&u,
             typename std::enable_if<std::is_convertible<U *, pointer>::value
                                         && std::is_convertible<D, deleter_type>::value
                                         && std::is_convertible<C, copier_type>::value,
                                     dummy_t_>::type
             = dummy_t_()) SPIMPL_NOEXCEPT : ptr_(std::move(u.ptr_)),
                                             copier_(std::move(u.copier_))
    {
    }

    impl_ptr &operator=(const impl_ptr &r)
    {
        if (this == &r)
            return *this;

        return operator=(r.clone());
    }

#ifndef SPIMPL_NO_CPP11_DEFAULT_MOVE_SPEC_FUNC
    impl_ptr &operator=(impl_ptr &&r) SPIMPL_NOEXCEPT = default;
#else
    impl_ptr &operator=(impl_ptr &&r) SPIMPL_NOEXCEPT
    {
        ptr_ = std::move(r.ptr_);
        copier_ = std::move(r.copier_);
        return *this;
    }
#endif

    template <class U, class D, class C>
    typename std::enable_if<std::is_convertible<U *, pointer>::value
                                && std::is_convertible<D, deleter_type>::value
                                && std::is_convertible<C, copier_type>::value,
                            impl_ptr &>::type
    operator=(impl_ptr<U, D, C> &&u) SPIMPL_NOEXCEPT
    {
        ptr_ = std::move(u.ptr_);
        copier_ = std::move(u.copier_);
        return *this;
    }

    template <class U, class D, class C>
    typename std::enable_if<std::is_convertible<U *, pointer>::value
                                && std::is_convertible<D, deleter_type>::value
                                && std::is_convertible<C, copier_type>::value,
                            impl_ptr &>::type
    operator=(const impl_ptr<U, D, C> &u)
    {
        return operator=(u.clone());
    }

//

#ifdef SPIMPL_HAS_AUTO_PTR
    template <class U>
    typename std::enable_if<std::is_convertible<U *, pointer>::value
                                && is_default_manageable::value,
                            impl_ptr &>::type
    operator=(std::auto_ptr<U> &&u) SPIMPL_NOEXCEPT
    {
        return operator=(impl_ptr(std::move(u)));
    }
#endif

    template <class U>
    typename std::enable_if<std::is_convertible<U *, pointer>::value
                                && is_default_manageable::value,
                            impl_ptr &>::type
    operator=(std::unique_ptr<U> &&u) SPIMPL_NOEXCEPT
    {
        return operator=(impl_ptr(std::move(u)));
    }

    impl_ptr clone() const
    {
        return impl_ptr(ptr_ ? copier_(ptr_.get()) : nullptr, ptr_.get_deleter(), copier_);
    }

    typename std::remove_reference<T>::type &operator*() const { return *ptr_; }
    pointer operator->() const SPIMPL_NOEXCEPT { return get(); }
    pointer get() const SPIMPL_NOEXCEPT { return ptr_.get(); }

    void swap(impl_ptr &u) SPIMPL_NOEXCEPT
    {
        using std::swap;
        ptr_.swap(u.ptr_);
        swap(copier_, u.copier_);
    }

    pointer release() SPIMPL_NOEXCEPT { return ptr_.release(); }

    unique_ptr_type release_unique() SPIMPL_NOEXCEPT { return std::move(ptr_); }

    explicit operator bool() const SPIMPL_NOEXCEPT { return static_cast<bool>(ptr_); }

    typename std::remove_reference<deleter_type>::type &get_deleter() SPIMPL_NOEXCEPT
    {
        return ptr_.get_deleter();
    }
    const typename std::remove_reference<deleter_type>::type &get_deleter() const SPIMPL_NOEXCEPT
    {
        return ptr_.get_deleter();
    }

    typename std::remove_reference<copier_type>::type &get_copier() SPIMPL_NOEXCEPT
    {
        return copier_;
    }
    const typename std::remove_reference<copier_type>::type &get_copier() const SPIMPL_NOEXCEPT
    {
        return copier_;
    }

private:
    unique_ptr_type ptr_;
    copier_type copier_;
};


template <class T, class D, class C>
inline void swap(impl_ptr<T, D, C> &l, impl_ptr<T, D, C> &r) SPIMPL_NOEXCEPT
{
    l.swap(r);
}


template <class T1, class D1, class C1, class T2, class D2, class C2>
inline bool operator==(const impl_ptr<T1, D1, C1> &l, const impl_ptr<T2, D2, C2> &r)
{
    return l.get() == r.get();
}

template <class T1, class D1, class C1, class T2, class D2, class C2>
inline bool operator!=(const impl_ptr<T1, D1, C1> &l, const impl_ptr<T2, D2, C2> &r)
{
    return !(l == r);
}

template <class T1, class D1, class C1, class T2, class D2, class C2>
inline bool operator<(const impl_ptr<T1, D1, C1> &l, const impl_ptr<T2, D2, C2> &r)
{
    using P1 = typename impl_ptr<T1, D1, C1>::pointer;
    using P2 = typename impl_ptr<T2, D2, C2>::pointer;
    using CT = typename std::common_type<P1, P2>::type;
    return std::less<CT>()(l.get(), r.get());
}

template <class T1, class D1, class C1, class T2, class D2, class C2>
inline bool operator>(const impl_ptr<T1, D1, C1> &l, const impl_ptr<T2, D2, C2> &r)
{
    return r < l;
}

template <class T1, class D1, class C1, class T2, class D2, class C2>
inline bool operator<=(const impl_ptr<T1, D1, C1> &l, const impl_ptr<T2, D2, C2> &r)
{
    return !(r < l);
}

template <class T1, class D1, class C1, class T2, class D2, class C2>
inline bool operator>=(const impl_ptr<T1, D1, C1> &l, const impl_ptr<T2, D2, C2> &r)
{
    return !(l < r);
}

template <class T, class D, class C>
inline bool operator==(const impl_ptr<T, D, C> &p, std::nullptr_t) SPIMPL_NOEXCEPT
{
    return !p;
}

template <class T, class D, class C>
inline bool operator==(std::nullptr_t, const impl_ptr<T, D, C> &p) SPIMPL_NOEXCEPT
{
    return !p;
}

template <class T, class D, class C>
inline bool operator!=(const impl_ptr<T, D, C> &p, std::nullptr_t) SPIMPL_NOEXCEPT
{
    return static_cast<bool>(p);
}

template <class T, class D, class C>
inline bool operator!=(std::nullptr_t, const impl_ptr<T, D, C> &p) SPIMPL_NOEXCEPT
{
    return static_cast<bool>(p);
}

template <class T, class D, class C>
inline bool operator<(const impl_ptr<T, D, C> &l, std::nullptr_t)
{
    using P = typename impl_ptr<T, D, C>::pointer;
    return std::less<P>()(l.get(), nullptr);
}

template <class T, class D, class C>
inline bool operator<(std::nullptr_t, const impl_ptr<T, D, C> &p)
{
    using P = typename impl_ptr<T, D, C>::pointer;
    return std::less<P>()(nullptr, p.get());
}

template <class T, class D, class C>
inline bool operator>(const impl_ptr<T, D, C> &p, std::nullptr_t)
{
    return nullptr < p;
}

template <class T, class D, class C>
inline bool operator>(std::nullptr_t, const impl_ptr<T, D, C> &p)
{
    return p < nullptr;
}

template <class T, class D, class C>
inline bool operator<=(const impl_ptr<T, D, C> &p, std::nullptr_t)
{
    return !(nullptr < p);
}

template <class T, class D, class C>
inline bool operator<=(std::nullptr_t, const impl_ptr<T, D, C> &p)
{
    return !(p < nullptr);
}

template <class T, class D, class C>
inline bool operator>=(const impl_ptr<T, D, C> &p, std::nullptr_t)
{
    return !(p < nullptr);
}

template <class T, class D, class C>
inline bool operator>=(std::nullptr_t, const impl_ptr<T, D, C> &p)
{
    return !(nullptr < p);
}


template <class T, class... Args>
inline impl_ptr<T> make_impl(Args &&... args)
{
    return impl_ptr<T>(new T(std::forward<Args>(args)...), &details::default_delete<T>,
                       &details::default_copy<T>);
}


// Helpers to manage unique impl, stored in std::unique_ptr

template <class T, class Deleter = void (*)(T *)>
using unique_impl_ptr = std::unique_ptr<T, Deleter>;

template <class T, class... Args>
inline unique_impl_ptr<T> make_unique_impl(Args &&... args)
{
    static_assert(!std::is_array<T>::value, "unique_impl_ptr does not support arrays");
    return unique_impl_ptr<T>(new T(std::forward<Args>(args)...), &details::default_delete<T>);
}
}

namespace std {
template <class T, class D, class C>
struct hash<spimpl::impl_ptr<T, D, C> > {
    using argument_type = spimpl::impl_ptr<T, D, C>;
    using result_type = size_t;

    result_type operator()(const argument_type &p) const SPIMPL_NOEXCEPT
    {
        return hash<typename argument_type::pointer>()(p.get());
    }
};
}

#endif // SPIMPL_H_