1 #ifndef BOOST_SHARED_PTR_HPP_INCLUDED

     2 #define BOOST_SHARED_PTR_HPP_INCLUDED

     3 

     4 //

     5 //  shared_ptr.hpp

     6 //

     7 //  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.

     8 //  Copyright (c) 2001-2006 Peter Dimov

     9 //

    10 //  Distributed under the Boost Software License, Version 1.0. (See

    11 //  accompanying file LICENSE_1_0.txt or copy at

    12 //  http://www.boost.org/LICENSE_1_0.txt)

    13 //

    14 //  See http://www.boost.org/libs/smart_ptr/shared_ptr.htm for documentation.

    15 //

    16 

    17 #include <boost/config.hpp>   // for broken compiler workarounds

    18 

    19 #if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)

    20 #include <boost/detail/shared_ptr_nmt.hpp>

    21 #else

    22 

    23 #include <memory>               // for std::auto_ptr

    24 

    25 #include <boost/assert.hpp>

    26 #include <boost/checked_delete.hpp>

    27 #include <boost/throw_exception.hpp>

    28 #include <boost/detail/shared_count.hpp>

    29 #include <boost/detail/workaround.hpp>

    30 

    31 #include <algorithm>            // for std::swap

    32 #include <functional>           // for std::less

    33 #include <typeinfo>             // for std::bad_cast

    34 #include <iosfwd>               // for std::basic_ostream

    35 

    36 #ifdef BOOST_MSVC  // moved here to work around VC++ compiler crash

    37 # pragma warning(push)

    38 # pragma warning(disable:4284) // odd return type for operator->

    39 #endif

    40 

    41 namespace boost

    42 {

    43 

    44 template<class T> class weak_ptr;

    45 template<class T> class enable_shared_from_this;

    46 

    47 namespace detail

    48 {

    49 

    50 struct static_cast_tag {};

    51 struct const_cast_tag {};

    52 struct dynamic_cast_tag {};

    53 struct polymorphic_cast_tag {};

    54 

    55 template<class T> struct shared_ptr_traits

    56 {

    57     typedef T & reference;

    58 };

    59 

    60 template<> struct shared_ptr_traits<void>

    61 {

    62     typedef void reference;

    63 };

    64 

    65 #if !defined(BOOST_NO_CV_VOID_SPECIALIZATIONS)

    66 

    67 template<> struct shared_ptr_traits<void const>

    68 {

    69     typedef void reference;

    70 };

    71 

    72 template<> struct shared_ptr_traits<void volatile>

    73 {

    74     typedef void reference;

    75 };

    76 

    77 template<> struct shared_ptr_traits<void const volatile>

    78 {

    79     typedef void reference;

    80 };

    81 

    82 #endif

    83 

    84 // enable_shared_from_this support

    85 

    86 template<class T, class Y> void sp_enable_shared_from_this( shared_count const & pn, boost::enable_shared_from_this<T> const * pe, Y const * px )

    87 {

    88     if(pe != 0) pe->_internal_weak_this._internal_assign(const_cast<Y*>(px), pn);

    89 }

    90 

    91 #ifdef sgi

    92 // Turn off: the last argument of the varargs function "sp_enable_shared_from_this" is unnamed

    93 # pragma set woff 3506

    94 #endif

    95 

    96 inline void sp_enable_shared_from_this( shared_count const & /*pn*/, ... )

    97 {

    98 }

    99 

   100 #ifdef sgi

   101 # pragma reset woff 3506

   102 #endif

   103 

   104 #if !defined( BOOST_NO_SFINAE ) && !defined( BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION ) && !defined( BOOST_NO_AUTO_PTR )

   105 

   106 // rvalue auto_ptr support based on a technique by Dave Abrahams

   107 

   108 template< class T, class R > struct sp_enable_if_auto_ptr

   109 {

   110 };

   111 

   112 template< class T, class R > struct sp_enable_if_auto_ptr< std::auto_ptr< T >, R >

   113 {

   114     typedef R type;

   115 }; 

   116 

   117 #endif

   118 

   119 } // namespace detail

   120 

   121 

   122 //

   123 //  shared_ptr

   124 //

   125 //  An enhanced relative of scoped_ptr with reference counted copy semantics.

   126 //  The object pointed to is deleted when the last shared_ptr pointing to it

   127 //  is destroyed or reset.

   128 //

   129 

   130 template<class T> class shared_ptr

   131 {

   132 private:

   133 

   134     // Borland 5.5.1 specific workaround

   135     typedef shared_ptr<T> this_type;

   136 

   137 public:

   138 

   139     typedef T element_type;

   140     typedef T value_type;

   141     typedef T * pointer;

   142     typedef typename boost::detail::shared_ptr_traits<T>::reference reference;

   143 

   144     shared_ptr(): px(0), pn() // never throws in 1.30+

   145     {

   146     }

   147 

   148     template<class Y>

   149     explicit shared_ptr( Y * p ): px( p ), pn( p ) // Y must be complete

   150     {

   151         boost::detail::sp_enable_shared_from_this( pn, p, p );

   152     }

   153 

   154     //

   155     // Requirements: D's copy constructor must not throw

   156     //

   157     // shared_ptr will release p by calling d(p)

   158     //

   159 

   160     template<class Y, class D> shared_ptr(Y * p, D d): px(p), pn(p, d)

   161     {

   162         boost::detail::sp_enable_shared_from_this( pn, p, p );

   163     }

   164 

   165     // As above, but with allocator. A's copy constructor shall not throw.

   166 

   167     template<class Y, class D, class A> shared_ptr( Y * p, D d, A a ): px( p ), pn( p, d, a )

   168     {

   169         boost::detail::sp_enable_shared_from_this( pn, p, p );

   170     }

   171 

   172 //  generated copy constructor, assignment, destructor are fine...

   173 

   174 //  except that Borland C++ has a bug, and g++ with -Wsynth warns

   175 #if defined(__BORLANDC__) || defined(__GNUC__)

   176 

   177     shared_ptr & operator=(shared_ptr const & r) // never throws

   178     {

   179         px = r.px;

   180         pn = r.pn; // shared_count::op= doesn't throw

   181         return *this;

   182     }

   183 

   184 #endif

   185 

   186     template<class Y>

   187     explicit shared_ptr(weak_ptr<Y> const & r): pn(r.pn) // may throw

   188     {

   189         // it is now safe to copy r.px, as pn(r.pn) did not throw

   190         px = r.px;

   191     }

   192 

   193     template<class Y>

   194     shared_ptr(shared_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws

   195     {

   196     }

   197 

   198     template<class Y>

   199     shared_ptr(shared_ptr<Y> const & r, boost::detail::static_cast_tag): px(static_cast<element_type *>(r.px)), pn(r.pn)

   200     {

   201     }

   202 

   203     template<class Y>

   204     shared_ptr(shared_ptr<Y> const & r, boost::detail::const_cast_tag): px(const_cast<element_type *>(r.px)), pn(r.pn)

   205     {

   206     }

   207 

   208     template<class Y>

   209     shared_ptr(shared_ptr<Y> const & r, boost::detail::dynamic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)

   210     {

   211         if(px == 0) // need to allocate new counter -- the cast failed

   212         {

   213             pn = boost::detail::shared_count();

   214         }

   215     }

   216 

   217     template<class Y>

   218     shared_ptr(shared_ptr<Y> const & r, boost::detail::polymorphic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)

   219     {

   220         if(px == 0)

   221         {

   222             boost::throw_exception(std::bad_cast());

   223         }

   224     }

   225 

   226 #ifndef BOOST_NO_AUTO_PTR

   227 

   228     template<class Y>

   229     explicit shared_ptr(std::auto_ptr<Y> & r): px(r.get()), pn()

   230     {

   231         Y * tmp = r.get();

   232         pn = boost::detail::shared_count(r);

   233         boost::detail::sp_enable_shared_from_this( pn, tmp, tmp );

   234     }

   235 

   236 #if !defined( BOOST_NO_SFINAE ) && !defined( BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION )

   237 

   238     template<class Ap>

   239     explicit shared_ptr( Ap r, typename boost::detail::sp_enable_if_auto_ptr<Ap, int>::type = 0 ): px( r.get() ), pn()

   240     {

   241         typename Ap::element_type * tmp = r.get();

   242         pn = boost::detail::shared_count( r );

   243         boost::detail::sp_enable_shared_from_this( pn, tmp, tmp );

   244     }

   245 

   246 

   247 #endif // BOOST_NO_SFINAE, BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

   248 

   249 #endif // BOOST_NO_AUTO_PTR

   250 

   251 #if !defined(BOOST_MSVC) || (BOOST_MSVC >= 1300)

   252 

   253     template<class Y>

   254     shared_ptr & operator=(shared_ptr<Y> const & r) // never throws

   255     {

   256         px = r.px;

   257         pn = r.pn; // shared_count::op= doesn't throw

   258         return *this;

   259     }

   260 

   261 #endif

   262 

   263 #ifndef BOOST_NO_AUTO_PTR

   264 

   265     template<class Y>

   266     shared_ptr & operator=( std::auto_ptr<Y> & r )

   267     {

   268         this_type(r).swap(*this);

   269         return *this;

   270     }

   271 

   272 #if !defined( BOOST_NO_SFINAE ) && !defined( BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION )

   273 

   274     template<class Ap>

   275     typename boost::detail::sp_enable_if_auto_ptr< Ap, shared_ptr & >::type operator=( Ap r )

   276     {

   277         this_type( r ).swap( *this );

   278         return *this;

   279     }

   280 

   281 

   282 #endif // BOOST_NO_SFINAE, BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

   283 

   284 #endif // BOOST_NO_AUTO_PTR

   285 

   286     void reset() // never throws in 1.30+

   287     {

   288         this_type().swap(*this);

   289     }

   290 

   291     template<class Y> void reset(Y * p) // Y must be complete

   292     {

   293         BOOST_ASSERT(p == 0 || p != px); // catch self-reset errors

   294         this_type(p).swap(*this);

   295     }

   296 

   297     template<class Y, class D> void reset( Y * p, D d )

   298     {

   299         this_type( p, d ).swap( *this );

   300     }

   301 

   302     template<class Y, class D, class A> void reset( Y * p, D d, A a )

   303     {

   304         this_type( p, d, a ).swap( *this );

   305     }

   306 

   307     reference operator* () const // never throws

   308     {

   309         BOOST_ASSERT(px != 0);

   310         return *px;

   311     }

   312 

   313     T * operator-> () const // never throws

   314     {

   315         BOOST_ASSERT(px != 0);

   316         return px;

   317     }

   318     

   319     T * get() const // never throws

   320     {

   321         return px;

   322     }

   323 

   324     // implicit conversion to "bool"

   325 

   326 #if defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x580)

   327 

   328     operator bool () const

   329     {

   330         return px != 0;

   331     }

   332 

   333 #elif defined( _MANAGED )

   334 

   335     static void unspecified_bool( this_type*** )

   336     {

   337     }

   338 

   339     typedef void (*unspecified_bool_type)( this_type*** );

   340 

   341     operator unspecified_bool_type() const // never throws

   342     {

   343         return px == 0? 0: unspecified_bool;

   344     }

   345 

   346 #elif \

   347     ( defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, < 0x3200) ) || \

   348     ( defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ < 304) )

   349 

   350     typedef T * (this_type::*unspecified_bool_type)() const;

   351     

   352     operator unspecified_bool_type() const // never throws

   353     {

   354         return px == 0? 0: &this_type::get;

   355     }

   356 

   357 #else 

   358 

   359     typedef T * this_type::*unspecified_bool_type;

   360 

   361     operator unspecified_bool_type() const // never throws

   362     {

   363         return px == 0? 0: &this_type::px;

   364     }

   365 

   366 #endif

   367 

   368     // operator! is redundant, but some compilers need it

   369 

   370     bool operator! () const // never throws

   371     {

   372         return px == 0;

   373     }

   374 

   375     bool unique() const // never throws

   376     {

   377         return pn.unique();

   378     }

   379 

   380     long use_count() const // never throws

   381     {

   382         return pn.use_count();

   383     }

   384 

   385     void swap(shared_ptr<T> & other) // never throws

   386     {

   387         std::swap(px, other.px);

   388         pn.swap(other.pn);

   389     }

   390 

   391     template<class Y> bool _internal_less(shared_ptr<Y> const & rhs) const

   392     {

   393         return pn < rhs.pn;

   394     }

   395 

   396     void * _internal_get_deleter(std::type_info const & ti) const

   397     {

   398         return pn.get_deleter(ti);

   399     }

   400 

   401 // Tasteless as this may seem, making all members public allows member templates

   402 // to work in the absence of member template friends. (Matthew Langston)

   403 

   404 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

   405 

   406 private:

   407 

   408     template<class Y> friend class shared_ptr;

   409     template<class Y> friend class weak_ptr;

   410 

   411 

   412 #endif

   413 

   414     T * px;                     // contained pointer

   415     boost::detail::shared_count pn;    // reference counter

   416 

   417 };  // shared_ptr

   418 

   419 template<class T, class U> inline bool operator==(shared_ptr<T> const & a, shared_ptr<U> const & b)

   420 {

   421     return a.get() == b.get();

   422 }

   423 

   424 template<class T, class U> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<U> const & b)

   425 {

   426     return a.get() != b.get();

   427 }

   428 

   429 #if __GNUC__ == 2 && __GNUC_MINOR__ <= 96

   430 

   431 // Resolve the ambiguity between our op!= and the one in rel_ops

   432 

   433 template<class T> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<T> const & b)

   434 {

   435     return a.get() != b.get();

   436 }

   437 

   438 #endif

   439 

   440 template<class T, class U> inline bool operator<(shared_ptr<T> const & a, shared_ptr<U> const & b)

   441 {

   442     return a._internal_less(b);

   443 }

   444 

   445 template<class T> inline void swap(shared_ptr<T> & a, shared_ptr<T> & b)

   446 {

   447     a.swap(b);

   448 }

   449 

   450 template<class T, class U> shared_ptr<T> static_pointer_cast(shared_ptr<U> const & r)

   451 {

   452     return shared_ptr<T>(r, boost::detail::static_cast_tag());

   453 }

   454 

   455 template<class T, class U> shared_ptr<T> const_pointer_cast(shared_ptr<U> const & r)

   456 {

   457     return shared_ptr<T>(r, boost::detail::const_cast_tag());

   458 }

   459 

   460 template<class T, class U> shared_ptr<T> dynamic_pointer_cast(shared_ptr<U> const & r)

   461 {

   462     return shared_ptr<T>(r, boost::detail::dynamic_cast_tag());

   463 }

   464 

   465 // shared_*_cast names are deprecated. Use *_pointer_cast instead.

   466 

   467 template<class T, class U> shared_ptr<T> shared_static_cast(shared_ptr<U> const & r)

   468 {

   469     return shared_ptr<T>(r, boost::detail::static_cast_tag());

   470 }

   471 

   472 template<class T, class U> shared_ptr<T> shared_dynamic_cast(shared_ptr<U> const & r)

   473 {

   474     return shared_ptr<T>(r, boost::detail::dynamic_cast_tag());

   475 }

   476 

   477 template<class T, class U> shared_ptr<T> shared_polymorphic_cast(shared_ptr<U> const & r)

   478 {

   479     return shared_ptr<T>(r, boost::detail::polymorphic_cast_tag());

   480 }

   481 

   482 template<class T, class U> shared_ptr<T> shared_polymorphic_downcast(shared_ptr<U> const & r)

   483 {

   484     BOOST_ASSERT(dynamic_cast<T *>(r.get()) == r.get());

   485     return shared_static_cast<T>(r);

   486 }

   487 

   488 // get_pointer() enables boost::mem_fn to recognize shared_ptr

   489 

   490 template<class T> inline T * get_pointer(shared_ptr<T> const & p)

   491 {

   492     return p.get();

   493 }

   494 

   495 // operator<<

   496 

   497 #if defined(__GNUC__) &&  (__GNUC__ < 3)

   498 

   499 template<class Y> std::ostream & operator<< (std::ostream & os, shared_ptr<Y> const & p)

   500 {

   501     os << p.get();

   502     return os;

   503 }

   504 

   505 #else

   506 

   507 // in STLport's no-iostreams mode no iostream symbols can be used

   508 #ifndef _STLP_NO_IOSTREAMS

   509 

   510 # if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, < 1300 && __SGI_STL_PORT)

   511 // MSVC6 has problems finding std::basic_ostream through the using declaration in namespace _STL

   512 using std::basic_ostream;

   513 template<class E, class T, class Y> basic_ostream<E, T> & operator<< (basic_ostream<E, T> & os, shared_ptr<Y> const & p)

   514 # else

   515 template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::basic_ostream<E, T> & os, shared_ptr<Y> const & p)

   516 # endif 

   517 {

   518     os << p.get();

   519     return os;

   520 }

   521 

   522 #endif // _STLP_NO_IOSTREAMS

   523 

   524 #endif // __GNUC__ < 3

   525 

   526 // get_deleter (experimental)

   527 

   528 #if ( defined(__GNUC__) && BOOST_WORKAROUND(__GNUC__, < 3) ) || \

   529     ( defined(__EDG_VERSION__) && BOOST_WORKAROUND(__EDG_VERSION__, <= 238) ) || \

   530     ( defined(__HP_aCC) && BOOST_WORKAROUND(__HP_aCC, <= 33500) )

   531 

   532 // g++ 2.9x doesn't allow static_cast<X const *>(void *)

   533 // apparently EDG 2.38 and HP aCC A.03.35 also don't accept it

   534 

   535 template<class D, class T> D * get_deleter(shared_ptr<T> const & p)

   536 {

   537     void const * q = p._internal_get_deleter(typeid(D));

   538     return const_cast<D *>(static_cast<D const *>(q));

   539 }

   540 

   541 #else

   542 

   543 template<class D, class T> D * get_deleter(shared_ptr<T> const & p)

   544 {

   545     return static_cast<D *>(p._internal_get_deleter(typeid(D)));

   546 }

   547 

   548 #endif

   549 

   550 } // namespace boost

   551 

   552 #ifdef BOOST_MSVC

   553 # pragma warning(pop)

   554 #endif    

   555 

   556 #endif  // #if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)

   557 

   558 #endif  // #ifndef BOOST_SHARED_PTR_HPP_INCLUDED