1 #ifndef BOOST_SHARED_PTR_HPP_INCLUDED
2 #define BOOST_SHARED_PTR_HPP_INCLUDED
7 // (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
8 // Copyright (c) 2001, 2002, 2003 Peter Dimov
10 // Permission to copy, use, modify, sell and distribute this software
11 // is granted provided this copyright notice appears in all copies.
12 // This software is provided "as is" without express or implied
13 // warranty, and with no claim as to its suitability for any purpose.
15 // See http://www.boost.org/libs/smart_ptr/shared_ptr.htm for documentation.
18 #include <boost/config.hpp> // for broken compiler workarounds
20 #if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)
21 #include <boost/detail/shared_ptr_nmt.hpp>
24 #include <boost/assert.hpp>
25 #include <boost/checked_delete.hpp>
26 #include <boost/throw_exception.hpp>
27 #include <boost/detail/shared_count.hpp>
28 #include <boost/detail/workaround.hpp>
30 #include <memory> // for std::auto_ptr
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
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->
44 template<class T> class weak_ptr;
45 template<class T> class enable_shared_from_this;
50 struct static_cast_tag {};
51 struct const_cast_tag {};
52 struct dynamic_cast_tag {};
53 struct polymorphic_cast_tag {};
55 template<class T> struct shared_ptr_traits
57 typedef T & reference;
60 template<> struct shared_ptr_traits<void>
62 typedef void reference;
65 #if !defined(BOOST_NO_CV_VOID_SPECIALIZATIONS)
67 template<> struct shared_ptr_traits<void const>
69 typedef void reference;
72 template<> struct shared_ptr_traits<void volatile>
74 typedef void reference;
77 template<> struct shared_ptr_traits<void const volatile>
79 typedef void reference;
84 // enable_shared_from_this support
86 template<class T, class Y> void sp_enable_shared_from_this(boost::enable_shared_from_this<T> * pe, Y * px, shared_count const & pn)
88 if(pe != 0) pe->_internal_weak_this._internal_assign(px, pn);
91 inline void sp_enable_shared_from_this(void const volatile *, void const volatile *, shared_count const &)
101 // An enhanced relative of scoped_ptr with reference counted copy semantics.
102 // The object pointed to is deleted when the last shared_ptr pointing to it
103 // is destroyed or reset.
106 template<class T> class shared_ptr
110 // Borland 5.5.1 specific workaround
111 typedef shared_ptr<T> this_type;
115 typedef T element_type;
116 typedef T value_type;
118 typedef typename detail::shared_ptr_traits<T>::reference reference;
120 shared_ptr(): px(0), pn() // never throws in 1.30+
125 explicit shared_ptr(Y * p): px(p), pn(p, checked_deleter<Y>()) // Y must be complete
127 detail::sp_enable_shared_from_this(p, p, pn);
131 // Requirements: D's copy constructor must not throw
133 // shared_ptr will release p by calling d(p)
136 template<class Y, class D> shared_ptr(Y * p, D d): px(p), pn(p, d)
138 detail::sp_enable_shared_from_this(p, p, pn);
141 // generated copy constructor, assignment, destructor are fine...
143 // except that Borland C++ has a bug, and g++ with -Wsynth warns
144 #if defined(__BORLANDC__) || defined(__GNUC__)
146 shared_ptr & operator=(shared_ptr const & r) // never throws
149 pn = r.pn; // shared_count::op= doesn't throw
156 explicit shared_ptr(weak_ptr<Y> const & r): pn(r.pn) // may throw
158 // it is now safe to copy r.px, as pn(r.pn) did not throw
163 shared_ptr(shared_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws
168 shared_ptr(shared_ptr<Y> const & r, detail::static_cast_tag): px(static_cast<element_type *>(r.px)), pn(r.pn)
173 shared_ptr(shared_ptr<Y> const & r, detail::const_cast_tag): px(const_cast<element_type *>(r.px)), pn(r.pn)
178 shared_ptr(shared_ptr<Y> const & r, detail::dynamic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)
180 if(px == 0) // need to allocate new counter -- the cast failed
182 pn = detail::shared_count();
187 shared_ptr(shared_ptr<Y> const & r, detail::polymorphic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)
191 boost::throw_exception(std::bad_cast());
195 #ifndef BOOST_NO_AUTO_PTR
198 explicit shared_ptr(std::auto_ptr<Y> & r): px(r.get()), pn()
201 pn = detail::shared_count(r);
202 detail::sp_enable_shared_from_this(tmp, tmp, pn);
207 #if !defined(BOOST_MSVC) || (BOOST_MSVC > 1200)
210 shared_ptr & operator=(shared_ptr<Y> const & r) // never throws
213 pn = r.pn; // shared_count::op= doesn't throw
219 #ifndef BOOST_NO_AUTO_PTR
222 shared_ptr & operator=(std::auto_ptr<Y> & r)
224 this_type(r).swap(*this);
230 void reset() // never throws in 1.30+
232 this_type().swap(*this);
235 template<class Y> void reset(Y * p) // Y must be complete
237 BOOST_ASSERT(p == 0 || p != px); // catch self-reset errors
238 this_type(p).swap(*this);
241 template<class Y, class D> void reset(Y * p, D d)
243 this_type(p, d).swap(*this);
246 reference operator* () const // never throws
248 BOOST_ASSERT(px != 0);
252 T * operator-> () const // never throws
254 BOOST_ASSERT(px != 0);
258 T * get() const // never throws
263 // implicit conversion to "bool"
265 #if defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x530)
267 operator bool () const
272 #elif defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
273 typedef T * (this_type::*unspecified_bool_type)() const;
275 operator unspecified_bool_type() const // never throws
277 return px == 0? 0: &this_type::get;
282 typedef T * this_type::*unspecified_bool_type;
284 operator unspecified_bool_type() const // never throws
286 return px == 0? 0: &this_type::px;
291 // operator! is redundant, but some compilers need it
293 bool operator! () const // never throws
298 bool unique() const // never throws
303 long use_count() const // never throws
305 return pn.use_count();
308 void swap(shared_ptr<T> & other) // never throws
310 std::swap(px, other.px);
314 template<class Y> bool _internal_less(shared_ptr<Y> const & rhs) const
319 void * _internal_get_deleter(std::type_info const & ti) const
321 return pn.get_deleter(ti);
324 // Tasteless as this may seem, making all members public allows member templates
325 // to work in the absence of member template friends. (Matthew Langston)
327 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
331 template<class Y> friend class shared_ptr;
332 template<class Y> friend class weak_ptr;
337 T * px; // contained pointer
338 detail::shared_count pn; // reference counter
342 template<class T, class U> inline bool operator==(shared_ptr<T> const & a, shared_ptr<U> const & b)
344 return a.get() == b.get();
347 template<class T, class U> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<U> const & b)
349 return a.get() != b.get();
352 #if __GNUC__ == 2 && __GNUC_MINOR__ <= 96
354 // Resolve the ambiguity between our op!= and the one in rel_ops
356 template<class T> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<T> const & b)
358 return a.get() != b.get();
363 template<class T, class U> inline bool operator<(shared_ptr<T> const & a, shared_ptr<U> const & b)
365 return a._internal_less(b);
368 template<class T> inline void swap(shared_ptr<T> & a, shared_ptr<T> & b)
373 template<class T, class U> shared_ptr<T> static_pointer_cast(shared_ptr<U> const & r)
375 return shared_ptr<T>(r, detail::static_cast_tag());
378 template<class T, class U> shared_ptr<T> const_pointer_cast(shared_ptr<U> const & r)
380 return shared_ptr<T>(r, detail::const_cast_tag());
383 template<class T, class U> shared_ptr<T> dynamic_pointer_cast(shared_ptr<U> const & r)
385 return shared_ptr<T>(r, detail::dynamic_cast_tag());
388 // shared_*_cast names are deprecated. Use *_pointer_cast instead.
390 template<class T, class U> shared_ptr<T> shared_static_cast(shared_ptr<U> const & r)
392 return shared_ptr<T>(r, detail::static_cast_tag());
395 template<class T, class U> shared_ptr<T> shared_dynamic_cast(shared_ptr<U> const & r)
397 return shared_ptr<T>(r, detail::dynamic_cast_tag());
400 template<class T, class U> shared_ptr<T> shared_polymorphic_cast(shared_ptr<U> const & r)
402 return shared_ptr<T>(r, detail::polymorphic_cast_tag());
405 template<class T, class U> shared_ptr<T> shared_polymorphic_downcast(shared_ptr<U> const & r)
407 BOOST_ASSERT(dynamic_cast<T *>(r.get()) == r.get());
408 return shared_static_cast<T>(r);
411 // get_pointer() enables boost::mem_fn to recognize shared_ptr
413 template<class T> inline T * get_pointer(shared_ptr<T> const & p)
420 #if defined(__GNUC__) && (__GNUC__ < 3)
422 template<class Y> std::ostream & operator<< (std::ostream & os, shared_ptr<Y> const & p)
430 # if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, <= 1200 && __SGI_STL_PORT)
431 // MSVC6 has problems finding std::basic_ostream through the using declaration in namespace _STL
432 using std::basic_ostream;
433 template<class E, class T, class Y> basic_ostream<E, T> & operator<< (basic_ostream<E, T> & os, shared_ptr<Y> const & p)
435 template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::basic_ostream<E, T> & os, shared_ptr<Y> const & p)
444 // get_deleter (experimental)
446 #if (defined(__GNUC__) && (__GNUC__ < 3)) || (defined(__EDG_VERSION__) && (__EDG_VERSION__ <= 238))
448 // g++ 2.9x doesn't allow static_cast<X const *>(void *)
449 // apparently EDG 2.38 also doesn't accept it
451 template<class D, class T> D * get_deleter(shared_ptr<T> const & p)
453 void const * q = p._internal_get_deleter(typeid(D));
454 return const_cast<D *>(static_cast<D const *>(q));
459 template<class D, class T> D * get_deleter(shared_ptr<T> const & p)
461 return static_cast<D *>(p._internal_get_deleter(typeid(D)));
469 # pragma warning(pop)
472 #endif // #if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)
474 #endif // #ifndef BOOST_SHARED_PTR_HPP_INCLUDED