ceph/src/boost/boost/any/basic_any.hpp

   1 // Copyright Ruslan Arutyunyan, 2019-2021.
   2 // Copyright Antony Polukhin, 2021-2022.
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See
   5 // accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7
   8 // Contributed by Ruslan Arutyunyan
   9
  10 #ifndef BOOST_ANYS_BASIC_ANY_HPP_INCLUDED
  11 #define BOOST_ANYS_BASIC_ANY_HPP_INCLUDED
  12
  13 #include <boost/config.hpp>
  14 #ifdef BOOST_HAS_PRAGMA_ONCE
  15 # pragma once
  16 #endif
  17
  18 #include <boost/any/bad_any_cast.hpp>
  19 #include <boost/any/fwd.hpp>
  20 #include <boost/assert.hpp>
  21 #include <boost/aligned_storage.hpp>
  22 #include <boost/type_index.hpp>
  23 #include <boost/type_traits/remove_reference.hpp>
  24 #include <boost/type_traits/decay.hpp>
  25 #include <boost/type_traits/remove_cv.hpp>
  26 #include <boost/type_traits/add_reference.hpp>
  27 #include <boost/type_traits/is_reference.hpp>
  28 #include <boost/type_traits/is_const.hpp>
  29 #include <boost/type_traits/is_nothrow_move_constructible.hpp>
  30 #include <boost/throw_exception.hpp>
  31 #include <boost/static_assert.hpp>
  32 #include <boost/utility/enable_if.hpp>
  33 #include <boost/core/addressof.hpp>
  34 #include <boost/type_traits/is_same.hpp>
  35 #include <boost/type_traits/conditional.hpp>
  36
  37 namespace boost {
  38
  39 namespace anys {
  40
  41     template <std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
  42     class basic_any
  43     {
  44         BOOST_STATIC_ASSERT_MSG(OptimizeForSize > 0 && OptimizeForAlignment > 0, "Size and Align shall be positive values");
  45         BOOST_STATIC_ASSERT_MSG(OptimizeForSize >= OptimizeForAlignment, "Size shall non less than Align");
  46         BOOST_STATIC_ASSERT_MSG((OptimizeForAlignment & (OptimizeForAlignment - 1)) == 0, "Align shall be a power of 2");
  47         BOOST_STATIC_ASSERT_MSG(OptimizeForSize % OptimizeForAlignment == 0, "Size shall be multiple of alignment");
  48     private:
  49         enum operation
  50         {
  51             Destroy,
  52             Move,
  53             Copy,
  54             AnyCast,
  55             UnsafeCast,
  56             Typeinfo
  57         };
  58
  59         template <typename ValueType>
  60         static void* small_manager(operation op, basic_any& left, const basic_any* right, const boost::typeindex::type_info* info)
  61         {
  62             switch (op)
  63             {
  64                 case Destroy:
  65                     BOOST_ASSERT(!left.empty());
  66                     reinterpret_cast<ValueType*>(&left.content.small_value)->~ValueType();
  67                     break;
  68                 case Move: {
  69                     BOOST_ASSERT(left.empty());
  70                     BOOST_ASSERT(right);
  71                     BOOST_ASSERT(!right->empty());
  72                     BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
  73                     ValueType* value = reinterpret_cast<ValueType*>(&const_cast<basic_any*>(right)->content.small_value);
  74 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  75                     new (&left.content.small_value) ValueType(std::move(*value));
  76 #else
  77                     new (&left.content.small_value) ValueType(*value);
  78 #endif
  79                     left.man = right->man;
  80                     reinterpret_cast<ValueType const*>(&right->content.small_value)->~ValueType();
  81                     const_cast<basic_any*>(right)->man = 0;
  82
  83                     };
  84                     break;
  85
  86                 case Copy:
  87                     BOOST_ASSERT(left.empty());
  88                     BOOST_ASSERT(right);
  89                     BOOST_ASSERT(!right->empty());
  90                     BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
  91                     new (&left.content.small_value) ValueType(*reinterpret_cast<const ValueType*>(&right->content.small_value));
  92                     left.man = right->man;
  93                     break;
  94                 case AnyCast:
  95                     BOOST_ASSERT(info);
  96                     BOOST_ASSERT(!left.empty());
  97                     return boost::typeindex::type_id<ValueType>() == *info ?
  98                             reinterpret_cast<typename remove_cv<ValueType>::type *>(&left.content.small_value) : 0;
  99                 case UnsafeCast:
 100                     BOOST_ASSERT(!left.empty());
 101                     return reinterpret_cast<typename remove_cv<ValueType>::type *>(&left.content.small_value);
 102                 case Typeinfo:
 103                     return const_cast<void*>(static_cast<const void*>(&boost::typeindex::type_id<ValueType>().type_info()));
 104             }
 105
 106             return 0;
 107         }
 108
 109         template <typename ValueType>
 110         static void* large_manager(operation op, basic_any& left, const basic_any* right, const boost::typeindex::type_info* info)
 111         {
 112             switch (op)
 113             {
 114                 case Destroy:
 115                     BOOST_ASSERT(!left.empty());
 116                     delete static_cast<ValueType*>(left.content.large_value);
 117                     break;
 118                 case Move:
 119                     BOOST_ASSERT(left.empty());
 120                     BOOST_ASSERT(right);
 121                     BOOST_ASSERT(!right->empty());
 122                     BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
 123                     left.content.large_value = right->content.large_value;
 124                     left.man = right->man;
 125                     const_cast<basic_any*>(right)->content.large_value = 0;
 126                     const_cast<basic_any*>(right)->man = 0;
 127                     break;
 128                 case Copy:
 129                     BOOST_ASSERT(left.empty());
 130                     BOOST_ASSERT(right);
 131                     BOOST_ASSERT(!right->empty());
 132                     BOOST_ASSERT(right->type() == boost::typeindex::type_id<ValueType>());
 133                     left.content.large_value = new ValueType(*static_cast<const ValueType*>(right->content.large_value));
 134                     left.man = right->man;
 135                     break;
 136                 case AnyCast:
 137                     BOOST_ASSERT(info);
 138                     BOOST_ASSERT(!left.empty());
 139                     return boost::typeindex::type_id<ValueType>() == *info ?
 140                             static_cast<typename remove_cv<ValueType>::type *>(left.content.large_value) : 0;
 141                 case UnsafeCast:
 142                     BOOST_ASSERT(!left.empty());
 143                     return reinterpret_cast<typename remove_cv<ValueType>::type *>(left.content.large_value);
 144                 case Typeinfo:
 145                     return const_cast<void*>(static_cast<const void*>(&boost::typeindex::type_id<ValueType>().type_info()));
 146             }
 147
 148             return 0;
 149         }
 150
 151         template <typename ValueType>
 152         struct is_small_object : boost::integral_constant<bool, sizeof(ValueType) <= OptimizeForSize &&
 153             boost::alignment_of<ValueType>::value <= OptimizeForAlignment &&
 154             boost::is_nothrow_move_constructible<ValueType>::value>
 155         {};
 156
 157         template <typename ValueType>
 158         static void create(basic_any& any, const ValueType& value, boost::true_type)
 159         {
 160             typedef typename boost::decay<const ValueType>::type DecayedType;
 161
 162             any.man = &small_manager<DecayedType>;
 163             new (&any.content.small_value) ValueType(value);
 164         }
 165
 166         template <typename ValueType>
 167         static void create(basic_any& any, const ValueType& value, boost::false_type)
 168         {
 169             typedef typename boost::decay<const ValueType>::type DecayedType;
 170
 171             any.man = &large_manager<DecayedType>;
 172             any.content.large_value = new DecayedType(value);
 173         }
 174
 175 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
 176         template <typename ValueType>
 177         static void create(basic_any& any, ValueType&& value, boost::true_type)
 178         {
 179             typedef typename boost::decay<const ValueType>::type DecayedType;
 180             any.man = &small_manager<DecayedType>;
 181             new (&any.content.small_value) DecayedType(static_cast<ValueType&&>(value));
 182         }
 183
 184         template <typename ValueType>
 185         static void create(basic_any& any, ValueType&& value, boost::false_type)
 186         {
 187             typedef typename boost::decay<const ValueType>::type DecayedType;
 188             any.man = &large_manager<DecayedType>;
 189             any.content.large_value = new DecayedType(static_cast<ValueType&&>(value));
 190         }
 191 #endif
 192     public: // non-type template parameters accessors
 193             static BOOST_CONSTEXPR_OR_CONST std::size_t buffer_size = OptimizeForSize;
 194             static BOOST_CONSTEXPR_OR_CONST std::size_t buffer_align = OptimizeForAlignment;
 195
 196     public: // structors
 197
 198         BOOST_CONSTEXPR basic_any() BOOST_NOEXCEPT
 199             : man(0), content()
 200         {
 201         }
 202
 203         template<typename ValueType>
 204         basic_any(const ValueType & value)
 205             : man(0), content()
 206         {
 207             BOOST_STATIC_ASSERT_MSG(
 208                 !(boost::is_same<ValueType, boost::any>::value),
 209                 "boost::anys::basic_any shall not be constructed from boost::any"
 210             );
 211             BOOST_STATIC_ASSERT_MSG(
 212                 !anys::detail::is_basic_any<ValueType>::value,
 213                 "boost::anys::basic_any<A, B> shall not be constructed from boost::anys::basic_any<C, D>"
 214             );
 215             create(*this, value, is_small_object<ValueType>());
 216         }
 217
 218         basic_any(const basic_any & other)
 219           : man(0), content()
 220         {
 221             if (other.man)
 222             {
 223                 other.man(Copy, *this, &other, 0);
 224             }
 225         }
 226
 227 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
 228         // Move constructor
 229         basic_any(basic_any&& other) BOOST_NOEXCEPT
 230           : man(0), content()
 231         {
 232             if (other.man)
 233             {
 234                 other.man(Move, *this, &other, 0);
 235             }
 236         }
 237
 238         // Perfect forwarding of ValueType
 239         template<typename ValueType>
 240         basic_any(ValueType&& value
 241             , typename boost::disable_if<boost::is_same<basic_any&, ValueType> >::type* = 0 // disable if value has type `basic_any&`
 242             , typename boost::disable_if<boost::is_const<ValueType> >::type* = 0) // disable if value has type `const ValueType&&`
 243           : man(0), content()
 244         {
 245             typedef typename boost::decay<ValueType>::type DecayedType;
 246             BOOST_STATIC_ASSERT_MSG(
 247                 !(boost::is_same<DecayedType, boost::any>::value),
 248                 "boost::anys::basic_any shall not be constructed from boost::any"
 249             );
 250             BOOST_STATIC_ASSERT_MSG(
 251                 !anys::detail::is_basic_any<DecayedType>::value,
 252                 "boost::anys::basic_any<A, B> shall not be constructed from boost::anys::basic_any<C, D>"
 253             );
 254             create(*this, static_cast<ValueType&&>(value), is_small_object<DecayedType>());
 255         }
 256 #endif
 257
 258         ~basic_any() BOOST_NOEXCEPT
 259         {
 260             if (man)
 261             {
 262                 man(Destroy, *this, 0, 0);
 263             }
 264         }
 265
 266     public: // modifiers
 267
 268         basic_any & swap(basic_any & rhs) BOOST_NOEXCEPT
 269         {
 270             if (this == &rhs)
 271             {
 272                 return *this;
 273             }
 274
 275             if (man && rhs.man)
 276             {
 277                 basic_any tmp;
 278                 rhs.man(Move, tmp, &rhs, 0);
 279                 man(Move, rhs, this, 0);
 280                 tmp.man(Move, *this, &tmp, 0);
 281             }
 282             else if (man)
 283             {
 284                 man(Move, rhs, this, 0);
 285             }
 286             else if (rhs.man)
 287             {
 288                 rhs.man(Move, *this, &rhs, 0);
 289             }
 290             return *this;
 291         }
 292
 293
 294 #ifdef BOOST_NO_CXX11_RVALUE_REFERENCES
 295         template<typename ValueType>
 296         basic_any & operator=(const ValueType & rhs)
 297         {
 298             BOOST_STATIC_ASSERT_MSG(
 299                 !(boost::is_same<ValueType, boost::any>::value),
 300                 "boost::any shall not be assigned into boost::anys::basic_any"
 301             );
 302             BOOST_STATIC_ASSERT_MSG(
 303                 !anys::detail::is_basic_any<ValueType>::value,
 304                 "boost::anys::basic_any<A, B> shall not be assigned into boost::anys::basic_any<C, D>"
 305             );
 306             basic_any(rhs).swap(*this);
 307             return *this;
 308         }
 309
 310         basic_any & operator=(basic_any rhs)
 311         {
 312             rhs.swap(*this);
 313             return *this;
 314         }
 315
 316 #else
 317         basic_any & operator=(const basic_any& rhs)
 318         {
 319             basic_any(rhs).swap(*this);
 320             return *this;
 321         }
 322
 323         // move assignment
 324         basic_any & operator=(basic_any&& rhs) BOOST_NOEXCEPT
 325         {
 326             rhs.swap(*this);
 327             basic_any().swap(rhs);
 328             return *this;
 329         }
 330
 331         // Perfect forwarding of ValueType
 332         template <class ValueType>
 333         basic_any & operator=(ValueType&& rhs)
 334         {
 335             typedef typename boost::decay<ValueType>::type DecayedType;
 336             BOOST_STATIC_ASSERT_MSG(
 337                 !(boost::is_same<DecayedType, boost::any>::value),
 338                 "boost::any shall not be assigned into boost::anys::basic_any"
 339             );
 340             BOOST_STATIC_ASSERT_MSG(
 341                 (!anys::detail::is_basic_any<DecayedType>::value || boost::is_same<DecayedType, basic_any>::value),
 342                 "boost::anys::basic_any<A, B> shall not be assigned into boost::anys::basic_any<C, D>"
 343             );
 344             basic_any(static_cast<ValueType&&>(rhs)).swap(*this);
 345             return *this;
 346         }
 347 #endif
 348
 349     public: // queries
 350
 351         bool empty() const BOOST_NOEXCEPT
 352         {
 353             return !man;
 354         }
 355
 356         void clear() BOOST_NOEXCEPT
 357         {
 358             basic_any().swap(*this);
 359         }
 360
 361         const boost::typeindex::type_info& type() const BOOST_NOEXCEPT
 362         {
 363             return man
 364                     ? *static_cast<const boost::typeindex::type_info*>(man(Typeinfo, const_cast<basic_any&>(*this), 0, 0))
 365                     : boost::typeindex::type_id<void>().type_info();
 366         }
 367
 368     private: // representation
 369
 370         template<typename ValueType, std::size_t Size, std::size_t Alignment>
 371         friend ValueType * any_cast(basic_any<Size, Alignment> *) BOOST_NOEXCEPT;
 372
 373         template<typename ValueType, std::size_t Size, std::size_t Alignment>
 374         friend ValueType * unsafe_any_cast(basic_any<Size, Alignment> *) BOOST_NOEXCEPT;
 375
 376         typedef void*(*manager)(operation op, basic_any& left, const basic_any* right, const boost::typeindex::type_info* info);
 377
 378         manager man;
 379
 380         union content {
 381             void * large_value;
 382             typename boost::aligned_storage<OptimizeForSize, OptimizeForAlignment>::type small_value;
 383         } content;
 384     };
 385
 386     template<std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
 387     void swap(basic_any<OptimizeForSize, OptimizeForAlignment>& lhs, basic_any<OptimizeForSize, OptimizeForAlignment>& rhs) BOOST_NOEXCEPT
 388     {
 389         lhs.swap(rhs);
 390     }
 391
 392     template<typename ValueType, std::size_t Size, std::size_t Alignment>
 393     ValueType * any_cast(basic_any<Size, Alignment> * operand) BOOST_NOEXCEPT
 394     {
 395         return operand->man ?
 396                 static_cast<typename remove_cv<ValueType>::type *>(operand->man(basic_any<Size, Alignment>::AnyCast, *operand, 0, &boost::typeindex::type_id<ValueType>().type_info()))
 397                 : 0;
 398     }
 399
 400     template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
 401     inline const ValueType * any_cast(const basic_any<OptimizeForSize, OptimizeForAlignment> * operand) BOOST_NOEXCEPT
 402     {
 403         return any_cast<ValueType>(const_cast<basic_any<OptimizeForSize, OptimizeForAlignment> *>(operand));
 404     }
 405
 406     template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
 407     ValueType any_cast(basic_any<OptimizeForSize, OptimizeForAlignment> & operand)
 408     {
 409         typedef typename remove_reference<ValueType>::type nonref;
 410
 411         nonref * result = any_cast<nonref>(boost::addressof(operand));
 412         if(!result)
 413             boost::throw_exception(bad_any_cast());
 414
 415         // Attempt to avoid construction of a temporary object in cases when
 416         // `ValueType` is not a reference. Example:
 417         // `static_cast<std::string>(*result);`
 418         // which is equal to `std::string(*result);`
 419         typedef typename boost::conditional<
 420             boost::is_reference<ValueType>::value,
 421             ValueType,
 422             typename boost::add_reference<ValueType>::type
 423         >::type ref_type;
 424
 425 #ifdef BOOST_MSVC
 426 #   pragma warning(push)
 427 #   pragma warning(disable: 4172) // "returning address of local variable or temporary" but *result is not local!
 428 #endif
 429         return static_cast<ref_type>(*result);
 430 #ifdef BOOST_MSVC
 431 #   pragma warning(pop)
 432 #endif
 433     }
 434
 435     template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
 436     inline ValueType any_cast(const basic_any<OptimizeForSize, OptimizeForAlignment> & operand)
 437     {
 438         typedef typename remove_reference<ValueType>::type nonref;
 439         return any_cast<const nonref &>(const_cast<basic_any<OptimizeForSize, OptimizeForAlignment> &>(operand));
 440     }
 441
 442 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
 443     template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
 444     inline ValueType any_cast(basic_any<OptimizeForSize, OptimizeForAlignment>&& operand)
 445     {
 446         BOOST_STATIC_ASSERT_MSG(
 447             boost::is_rvalue_reference<ValueType&&>::value /*true if ValueType is rvalue or just a value*/
 448             || boost::is_const< typename boost::remove_reference<ValueType>::type >::value,
 449             "boost::any_cast shall not be used for getting nonconst references to temporary objects"
 450         );
 451         return any_cast<ValueType>(operand);
 452     }
 453 #endif
 454
 455
 456     // Note: The "unsafe" versions of any_cast are not part of the
 457     // public interface and may be removed at any time. They are
 458     // required where we know what type is stored in the any and can't
 459     // use typeid() comparison, e.g., when our types may travel across
 460     // different shared libraries.
 461     template<typename ValueType, std::size_t OptimizedForSize, std::size_t OptimizeForAlignment>
 462     inline ValueType * unsafe_any_cast(basic_any<OptimizedForSize, OptimizeForAlignment> * operand) BOOST_NOEXCEPT
 463     {
 464         return static_cast<ValueType*>(operand->man(basic_any<OptimizedForSize, OptimizeForAlignment>::UnsafeCast, *operand, 0, 0));
 465     }
 466
 467     template<typename ValueType, std::size_t OptimizeForSize, std::size_t OptimizeForAlignment>
 468     inline const ValueType * unsafe_any_cast(const basic_any<OptimizeForSize, OptimizeForAlignment> * operand) BOOST_NOEXCEPT
 469     {
 470         return unsafe_any_cast<ValueType>(const_cast<basic_any<OptimizeForSize, OptimizeForAlignment> *>(operand));
 471     }
 472
 473 } // namespace anys
 474
 475 using boost::anys::any_cast;
 476 using boost::anys::unsafe_any_cast;
 477
 478 } // namespace boost
 479
 480 #endif // #ifndef BOOST_ANYS_BASIC_ANY_HPP_INCLUDED