llvm-project/libcxx/include/experimental/any

591 lines
15 KiB
C++

// -*- C++ -*-
//===------------------------------ any -----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_EXPERIMENTAL_ANY
#define _LIBCPP_EXPERIMENTAL_ANY
/*
experimental/any synopsis
namespace std {
namespace experimental {
inline namespace fundamentals_v1 {
class bad_any_cast : public bad_cast
{
public:
virtual const char* what() const noexcept;
};
class any
{
public:
// 6.3.1 any construct/destruct
any() noexcept;
any(const any& other);
any(any&& other) noexcept;
template <class ValueType>
any(ValueType&& value);
~any();
// 6.3.2 any assignments
any& operator=(const any& rhs);
any& operator=(any&& rhs) noexcept;
template <class ValueType>
any& operator=(ValueType&& rhs);
// 6.3.3 any modifiers
void clear() noexcept;
void swap(any& rhs) noexcept;
// 6.3.4 any observers
bool empty() const noexcept;
const type_info& type() const noexcept;
};
// 6.4 Non-member functions
void swap(any& x, any& y) noexcept;
template<class ValueType>
ValueType any_cast(const any& operand);
template<class ValueType>
ValueType any_cast(any& operand);
template<class ValueType>
ValueType any_cast(any&& operand);
template<class ValueType>
const ValueType* any_cast(const any* operand) noexcept;
template<class ValueType>
ValueType* any_cast(any* operand) noexcept;
} // namespace fundamentals_v1
} // namespace experimental
} // namespace std
*/
#include <experimental/__config>
#include <memory>
#include <new>
#include <typeinfo>
#include <type_traits>
#include <cstdlib>
#include <cassert>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_LFTS
class _LIBCPP_EXCEPTION_ABI bad_any_cast : public bad_cast
{
public:
virtual const char* what() const _NOEXCEPT;
};
#if _LIBCPP_STD_VER > 11 // C++ > 11
_LIBCPP_NORETURN _LIBCPP_INLINE_VISIBILITY
inline void __throw_bad_any_cast()
{
#ifndef _LIBCPP_NO_EXCEPTIONS
throw bad_any_cast();
#else
assert(!"bad_any_cast");
#endif
}
// Forward declarations
class any;
template <class _ValueType>
typename add_pointer<typename add_const<_ValueType>::type>::type
any_cast(any const *) _NOEXCEPT;
template <class _ValueType>
typename add_pointer<_ValueType>::type
any_cast(any *) _NOEXCEPT;
namespace __any_imp
{
typedef typename aligned_storage<3*sizeof(void*), alignment_of<void*>::value>::type
_Buffer;
template <class _Tp>
struct _IsSmallObject
: public integral_constant<bool
, sizeof(_Tp) <= sizeof(_Buffer)
&& alignment_of<_Buffer>::value
% alignment_of<_Tp>::value == 0
&& is_nothrow_move_constructible<_Tp>::value
>
{};
enum class _Action
{
_Destroy,
_Copy,
_Move,
_Get,
_TypeInfo
};
template <class _Tp>
struct _SmallHandler;
template <class _Tp>
struct _LargeHandler;
template <class _Tp>
using _Handler = typename conditional<_IsSmallObject<_Tp>::value
, _SmallHandler<_Tp>
, _LargeHandler<_Tp>
>::type;
template <class _ValueType>
using _EnableIfNotAny = typename
enable_if<
!is_same<typename decay<_ValueType>::type, any>::value
>::type;
} // namespace __any_imp
class any
{
public:
// 6.3.1 any construct/destruct
_LIBCPP_INLINE_VISIBILITY
any() _NOEXCEPT : __h(nullptr) {}
_LIBCPP_INLINE_VISIBILITY
any(any const & __other) : __h(nullptr)
{
if (__other.__h) __other.__call(_Action::_Copy, this);
}
_LIBCPP_INLINE_VISIBILITY
any(any && __other) _NOEXCEPT : __h(nullptr)
{
if (__other.__h) __other.__call(_Action::_Move, this);
}
template <
class _ValueType
, class = __any_imp::_EnableIfNotAny<_ValueType>
>
any(_ValueType && __value);
_LIBCPP_INLINE_VISIBILITY
~any()
{
this->clear();
}
// 6.3.2 any assignments
_LIBCPP_INLINE_VISIBILITY
any & operator=(any const & __rhs)
{
any(__rhs).swap(*this);
return *this;
}
_LIBCPP_INLINE_VISIBILITY
any & operator=(any && __rhs) _NOEXCEPT
{
any(_VSTD::move(__rhs)).swap(*this);
return *this;
}
template <
class _ValueType
, class = __any_imp::_EnableIfNotAny<_ValueType>
>
any & operator=(_ValueType && __rhs);
// 6.3.3 any modifiers
_LIBCPP_INLINE_VISIBILITY
void clear() _NOEXCEPT
{
if (__h) this->__call(_Action::_Destroy);
}
void swap(any & __rhs) _NOEXCEPT;
// 6.3.4 any observers
_LIBCPP_INLINE_VISIBILITY
bool empty() const _NOEXCEPT
{
return __h == nullptr;
}
#if !defined(_LIBCPP_NO_RTTI)
_LIBCPP_INLINE_VISIBILITY
const type_info & type() const _NOEXCEPT
{
if (__h) {
return *static_cast<type_info const *>(this->__call(_Action::_TypeInfo));
} else {
return typeid(void);
}
}
#endif
private:
typedef __any_imp::_Action _Action;
typedef void* (*_HandleFuncPtr)(_Action, any const *, any *, const type_info *);
union _Storage
{
void * __ptr;
__any_imp::_Buffer __buf;
};
_LIBCPP_ALWAYS_INLINE
void * __call(_Action __a, any * __other = nullptr,
type_info const * __info = nullptr) const
{
return __h(__a, this, __other, __info);
}
_LIBCPP_ALWAYS_INLINE
void * __call(_Action __a, any * __other = nullptr,
type_info const * __info = nullptr)
{
return __h(__a, this, __other, __info);
}
template <class>
friend struct __any_imp::_SmallHandler;
template <class>
friend struct __any_imp::_LargeHandler;
template <class _ValueType>
friend typename add_pointer<typename add_const<_ValueType>::type>::type
any_cast(any const *) _NOEXCEPT;
template <class _ValueType>
friend typename add_pointer<_ValueType>::type
any_cast(any *) _NOEXCEPT;
_HandleFuncPtr __h;
_Storage __s;
};
namespace __any_imp
{
template <class _Tp>
struct _LIBCPP_TYPE_VIS_ONLY _SmallHandler
{
_LIBCPP_INLINE_VISIBILITY
static void* __handle(_Action __act, any const * __this, any * __other,
type_info const * __info)
{
switch (__act)
{
case _Action::_Destroy:
__destroy(const_cast<any &>(*__this));
return nullptr;
case _Action::_Copy:
__copy(*__this, *__other);
return nullptr;
case _Action::_Move:
__move(const_cast<any &>(*__this), *__other);
return nullptr;
case _Action::_Get:
return __get(const_cast<any &>(*__this), __info);
case _Action::_TypeInfo:
return __type_info();
}
}
template <class _Up>
_LIBCPP_INLINE_VISIBILITY
static void __create(any & __dest, _Up && __v)
{
::new (static_cast<void*>(&__dest.__s.__buf)) _Tp(_VSTD::forward<_Up>(__v));
__dest.__h = &_SmallHandler::__handle;
}
private:
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void __destroy(any & __this)
{
_Tp & __value = *static_cast<_Tp *>(static_cast<void*>(&__this.__s.__buf));
__value.~_Tp();
__this.__h = nullptr;
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void __copy(any const & __this, any & __dest)
{
_SmallHandler::__create(__dest, *static_cast<_Tp const *>(
static_cast<void const *>(&__this.__s.__buf)));
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void __move(any & __this, any & __dest)
{
_SmallHandler::__create(__dest, _VSTD::move(
*static_cast<_Tp*>(static_cast<void*>(&__this.__s.__buf))));
__destroy(__this);
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void* __get(any & __this, type_info const * __info)
{
#if !defined(_LIBCPP_NO_RTTI)
if (typeid(_Tp) == *__info) {
return static_cast<void*>(&__this.__s.__buf);
}
return nullptr;
#else
return static_cast<void*>(&__this.__s.__buf);
#endif
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void* __type_info()
{
#if !defined(_LIBCPP_NO_RTTI)
return const_cast<void*>(static_cast<void const *>(&typeid(_Tp)));
#else
return nullptr;
#endif
}
};
template <class _Tp>
struct _LIBCPP_TYPE_VIS_ONLY _LargeHandler
{
_LIBCPP_INLINE_VISIBILITY
static void* __handle(_Action __act, any const * __this, any * __other,
type_info const * __info)
{
switch (__act)
{
case _Action::_Destroy:
__destroy(const_cast<any &>(*__this));
return nullptr;
case _Action::_Copy:
__copy(*__this, *__other);
return nullptr;
case _Action::_Move:
__move(const_cast<any &>(*__this), *__other);
return nullptr;
case _Action::_Get:
return __get(const_cast<any &>(*__this), __info);
case _Action::_TypeInfo:
return __type_info();
}
}
template <class _Up>
_LIBCPP_INLINE_VISIBILITY
static void __create(any & __dest, _Up && __v)
{
typedef allocator<_Tp> _Alloc;
typedef __allocator_destructor<_Alloc> _Dp;
_Alloc __a;
unique_ptr<_Tp, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
::new ((void*)__hold.get()) _Tp(_VSTD::forward<_Up>(__v));
__dest.__s.__ptr = __hold.release();
__dest.__h = &_LargeHandler::__handle;
}
private:
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void __destroy(any & __this)
{
delete static_cast<_Tp*>(__this.__s.__ptr);
__this.__h = nullptr;
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void __copy(any const & __this, any & __dest)
{
_LargeHandler::__create(__dest, *static_cast<_Tp const *>(__this.__s.__ptr));
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void __move(any & __this, any & __dest)
{
__dest.__s.__ptr = __this.__s.__ptr;
__dest.__h = &_LargeHandler::__handle;
__this.__h = nullptr;
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void* __get(any & __this, type_info const * __info)
{
#if !defined(_LIBCPP_NO_RTTI)
if (typeid(_Tp) == *__info) {
return static_cast<void*>(__this.__s.__ptr);
}
return nullptr;
#else
return static_cast<void*>(__this.__s.__ptr);
#endif
}
_LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
static void* __type_info()
{
#if !defined(_LIBCPP_NO_RTTI)
return const_cast<void*>(static_cast<void const *>(&typeid(_Tp)));
#else
return nullptr;
#endif
}
};
} // namespace __any_imp
template <class _ValueType, class>
_LIBCPP_INLINE_VISIBILITY
any::any(_ValueType && __v) : __h(nullptr)
{
typedef typename decay<_ValueType>::type _Tp;
static_assert(is_copy_constructible<_Tp>::value,
"_ValueType must be CopyConstructible.");
typedef __any_imp::_Handler<_Tp> _HandlerType;
_HandlerType::__create(*this, _VSTD::forward<_ValueType>(__v));
}
template <class _ValueType, class>
_LIBCPP_INLINE_VISIBILITY
any & any::operator=(_ValueType && __v)
{
typedef typename decay<_ValueType>::type _Tp;
static_assert(is_copy_constructible<_Tp>::value,
"_ValueType must be CopyConstructible.");
any(_VSTD::forward<_ValueType>(__v)).swap(*this);
return *this;
}
inline _LIBCPP_INLINE_VISIBILITY
void any::swap(any & __rhs) _NOEXCEPT
{
if (__h && __rhs.__h) {
any __tmp;
__rhs.__call(_Action::_Move, &__tmp);
this->__call(_Action::_Move, &__rhs);
__tmp.__call(_Action::_Move, this);
}
else if (__h) {
this->__call(_Action::_Move, &__rhs);
}
else if (__rhs.__h) {
__rhs.__call(_Action::_Move, this);
}
}
// 6.4 Non-member functions
inline _LIBCPP_INLINE_VISIBILITY
void swap(any & __lhs, any & __rhs) _NOEXCEPT
{
__lhs.swap(__rhs);
}
template <class _ValueType>
_LIBCPP_INLINE_VISIBILITY
_ValueType any_cast(any const & __v)
{
static_assert(
is_reference<_ValueType>::value
|| is_copy_constructible<_ValueType>::value,
"_ValueType is required to be a reference or a CopyConstructible type.");
typedef typename add_const<typename remove_reference<_ValueType>::type>::type
_Tp;
_Tp * __tmp = any_cast<_Tp>(&__v);
if (__tmp == nullptr)
__throw_bad_any_cast();
return *__tmp;
}
template <class _ValueType>
_LIBCPP_INLINE_VISIBILITY
_ValueType any_cast(any & __v)
{
static_assert(
is_reference<_ValueType>::value
|| is_copy_constructible<_ValueType>::value,
"_ValueType is required to be a reference or a CopyConstructible type.");
typedef typename remove_reference<_ValueType>::type _Tp;
_Tp * __tmp = any_cast<_Tp>(&__v);
if (__tmp == nullptr)
__throw_bad_any_cast();
return *__tmp;
}
template <class _ValueType>
_LIBCPP_INLINE_VISIBILITY
_ValueType any_cast(any && __v)
{
static_assert(
is_reference<_ValueType>::value
|| is_copy_constructible<_ValueType>::value,
"_ValueType is required to be a reference or a CopyConstructible type.");
typedef typename remove_reference<_ValueType>::type _Tp;
_Tp * __tmp = any_cast<_Tp>(&__v);
if (__tmp == nullptr)
__throw_bad_any_cast();
return *__tmp;
}
template <class _ValueType>
inline _LIBCPP_INLINE_VISIBILITY
typename add_pointer<typename add_const<_ValueType>::type>::type
any_cast(any const * __any) _NOEXCEPT
{
static_assert(!is_reference<_ValueType>::value,
"_ValueType may not be a reference.");
return any_cast<_ValueType>(const_cast<any *>(__any));
}
template <class _ValueType>
_LIBCPP_INLINE_VISIBILITY
typename add_pointer<_ValueType>::type
any_cast(any * __any) _NOEXCEPT
{
using __any_imp::_Action;
static_assert(!is_reference<_ValueType>::value,
"_ValueType may not be a reference.");
typedef typename add_pointer<_ValueType>::type _ReturnType;
if (__any && __any->__h) {
return static_cast<_ReturnType>(
__any->__call(_Action::_Get, nullptr,
#if !defined(_LIBCPP_NO_RTTI)
&typeid(_ValueType)
#else
nullptr
#endif
));
}
return nullptr;
}
#endif // _LIBCPP_STD_VER > 11
_LIBCPP_END_NAMESPACE_LFTS
#endif // _LIBCPP_EXPERIMENTAL_ANY