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편집 파일: default_delete.hpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2014-2014. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/move for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_MOVE_DEFAULT_DELETE_HPP_INCLUDED
#define BOOST_MOVE_DEFAULT_DELETE_HPP_INCLUDED

#ifndef BOOST_CONFIG_HPP
# include <boost/config.hpp>
#endif
#
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif

#include <boost/move/detail/config_begin.hpp>
#include <boost/move/detail/workaround.hpp>
#include <boost/move/detail/unique_ptr_meta_utils.hpp>
#include <boost/move/utility_core.hpp>

#include <cstddef> //For std::size_t,std::nullptr_t

//!\file
//! Describes the default deleter (destruction policy) of <tt>unique_ptr</tt>: <tt>default_delete</tt>.

namespace boost{
// @cond
namespace move_upd {

namespace bmupmu = ::boost::move_upmu;

////////////////////////////////////////
////        enable_def_del
////////////////////////////////////////

//compatible with a pointer type T*:
//When either Y* is convertible to T*
//Y is U[N] and T is U cv []
template<class U, class T>
struct def_del_compatible_cond
 : bmupmu::is_convertible<U*, T*>
{};

template<class U, class T, std::size_t N>
struct def_del_compatible_cond<U[N], T[]>
 : def_del_compatible_cond<U[], T[]>
{};

template<class U, class T, class Type = bmupmu::nat>
struct enable_def_del
 : bmupmu::enable_if_c<def_del_compatible_cond<U, T>::value, Type>
{};

////////////////////////////////////////
////        enable_defdel_call
////////////////////////////////////////

//When 2nd is T[N], 1st(*)[N] shall be convertible to T(*)[N]; 
//When 2nd is T[],  1st(*)[] shall be convertible to T(*)[]; 
//Otherwise, 1st* shall be convertible to 2nd*.

template<class U, class T, class Type = bmupmu::nat>
struct enable_defdel_call
 : public enable_def_del<U, T, Type>
{};

template<class U, class T, class Type>
struct enable_defdel_call<U, T[], Type>
 : public enable_def_del<U[], T[], Type>
{};

template<class U, class T, class Type, std::size_t N>
struct enable_defdel_call<U, T[N], Type>
 : public enable_def_del<U[N], T[N], Type>
{};

////////////////////////////////////////
////     Some bool literal zero conversion utilities
////////////////////////////////////////

struct bool_conversion {int for_bool; int for_arg(); };
typedef int bool_conversion::* explicit_bool_arg;

#if !defined(BOOST_NO_CXX11_NULLPTR) && !defined(BOOST_NO_CXX11_DECLTYPE)
   typedef decltype(nullptr) nullptr_type;
#elif !defined(BOOST_NO_CXX11_NULLPTR)
   typedef std::nullptr_t nullptr_type;
#else
   typedef int (bool_conversion::*nullptr_type)();
#endif

template<bool B>
struct is_array_del
{};

template<class T>
void call_delete(T *p, is_array_del<true>)
{
 delete [] p;
}

template<class T>
void call_delete(T *p, is_array_del<false>)
{
 delete p;
}

template< class T, class U
 , bool enable = def_del_compatible_cond< U, T>::value &&
 !move_upmu::is_array<T>::value &&
 !move_upmu::is_same<typename move_upmu::remove_cv<T>::type, void>::value &&
 !move_upmu::is_same<typename move_upmu::remove_cv::type, typename move_upmu::remove_cv<T>::type>::value
 >
struct missing_virtual_destructor_default_delete
{ static const bool value = !move_upmu::has_virtual_destructor<T>::value; };

template<class T, class U>
struct missing_virtual_destructor_default_delete<T, U, false>
{ static const bool value = false; };

//////////////////////////////////////
//       missing_virtual_destructor
//////////////////////////////////////

template<class Deleter, class U>
struct missing_virtual_destructor
{ static const bool value = false; };

template<class T, class U>
struct missing_virtual_destructor< ::boost::movelib::default_delete<T>, U >
 : missing_virtual_destructor_default_delete<T, U>
{};

}  //namespace move_upd {
// @endcond

namespace movelib {

namespace bmupd = boost::move_upd;
namespace bmupmu = ::boost::move_upmu;

//!The class template <tt>default_delete</tt> serves as the default deleter
//!(destruction policy) for the class template <tt>unique_ptr</tt>.
//!
//! \tparam T The type to be deleted. It may be an incomplete type
template <class T>
struct default_delete
{
 //! Default constructor.
 //!
 BOOST_CONSTEXPR default_delete()
 //Avoid "defaulted on its first declaration must not have an exception-specification" error for GCC 4.6
 #if !defined(BOOST_GCC) || (BOOST_GCC < 40600 && BOOST_GCC >= 40700) || defined(BOOST_MOVE_DOXYGEN_INVOKED)
 BOOST_NOEXCEPT
 #endif
 #if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) || defined(BOOST_MOVE_DOXYGEN_INVOKED)
 = default;
 #else
 {};
 #endif

#if defined(BOOST_MOVE_DOXYGEN_INVOKED)
 //! Trivial copy constructor
 //!
 default_delete(const default_delete&) BOOST_NOEXCEPT = default;
 //! Trivial assignment
 //!
 default_delete &operator=(const default_delete&) BOOST_NOEXCEPT = default;
 #else
 typedef typename bmupmu::remove_extent<T>::type element_type;
 #endif

//! Effects: Constructs a default_delete object from another <tt>default_delete</tt> object.
 //!
 //! Remarks: This constructor shall not participate in overload resolution unless:
 //! - If T is not an array type and U* is implicitly convertible to T*.
 //! - If T is an array type and U* is a more CV qualified pointer to remove_extent<T>::type.
 template <class U>
 default_delete(const default_delete&
 BOOST_MOVE_DOCIGN(BOOST_MOVE_I typename bmupd::enable_def_del::type* =0)
 ) BOOST_NOEXCEPT
 {
 //If T is not an array type, U derives from T
 //and T has no virtual destructor, then you have a problem
 BOOST_MOVE_STATIC_ASSERT(( !bmupd::missing_virtual_destructor<default_delete, U>::value ));
 }

//! Effects: Constructs a default_delete object from another <tt>default_delete</tt> object.
 //!
 //! Remarks: This constructor shall not participate in overload resolution unless:
 //! - If T is not an array type and U* is implicitly convertible to T*.
 //! - If T is an array type and U* is a more CV qualified pointer to remove_extent<T>::type.
 template <class U>
 BOOST_MOVE_DOC1ST(default_delete&, 
 typename bmupd::enable_def_del::type)
 operator=(const default_delete&) BOOST_NOEXCEPT
 {
 //If T is not an array type, U derives from T
 //and T has no virtual destructor, then you have a problem
 BOOST_MOVE_STATIC_ASSERT(( !bmupd::missing_virtual_destructor<default_delete, U>::value ));
 return *this;
 }

//! Effects: if T is not an array type, calls <tt>delete</tt> on static_cast<T*>(ptr),
 //! otherwise calls <tt>delete[]</tt> on static_cast<remove_extent<T>::type*>(ptr).
 //!
 //! Remarks: If U is an incomplete type, the program is ill-formed.
 //! This operator shall not participate in overload resolution unless:
 //! - T is not an array type and U* is convertible to T*, OR
 //! - T is an array type, and remove_cv::type is the same type as
 //! remove_cv<remove_extent<T>::type>::type and U* is convertible to remove_extent<T>::type*.
 template <class U>
 BOOST_MOVE_DOC1ST(void, typename bmupd::enable_defdel_call::type)
 operator()(U* ptr) const BOOST_NOEXCEPT
 {
 //U must be a complete type
 BOOST_MOVE_STATIC_ASSERT(sizeof(U) > 0);
 //If T is not an array type, U derives from T
 //and T has no virtual destructor, then you have a problem
 BOOST_MOVE_STATIC_ASSERT(( !bmupd::missing_virtual_destructor<default_delete, U>::value ));
 element_type * const p = static_cast<element_type*>(ptr);
 move_upd::call_delete(p, move_upd::is_array_del<bmupmu::is_array<T>::value>());
 }

//! Effects: Same as <tt>(*this)(static_cast<element_type*>(nullptr))</tt>.
 //!
 void operator()(BOOST_MOVE_DOC0PTR(bmupd::nullptr_type)) const BOOST_NOEXCEPT
 { BOOST_MOVE_STATIC_ASSERT(sizeof(element_type) > 0); }
};

}  //namespace movelib {
}  //namespace boost{

#include <boost/move/detail/config_end.hpp>

#endif   //#ifndef BOOST_MOVE_DEFAULT_DELETE_HPP_INCLUDED