boost/shared_ptr.hpp
#ifndef BOOST_SHARED_PTR_HPP_INCLUDED
#define BOOST_SHARED_PTR_HPP_INCLUDED
//
// shared_ptr.hpp
//
// (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
// Copyright (c) 2001, 2002, 2003 Peter Dimov
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
// See http://www.boost.org/libs/smart_ptr/shared_ptr.htm for documentation.
//
#include <boost/config.hpp> // for broken compiler workarounds
#if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)
#include <boost/detail/shared_ptr_nmt.hpp>
#else
#include <boost/assert.hpp>
#include <boost/checked_delete.hpp>
#include <boost/throw_exception.hpp>
#include <boost/detail/shared_count.hpp>
#include <boost/detail/workaround.hpp>
#include <memory> // for std::auto_ptr
#include <algorithm> // for std::swap
#include <functional> // for std::less
#include <typeinfo> // for std::bad_cast
#include <iosfwd> // for std::basic_ostream
#ifdef BOOST_MSVC // moved here to work around VC++ compiler crash
# pragma warning(push)
# pragma warning(disable:4284) // odd return type for operator->
#endif
namespace boost
{
template<class T> class weak_ptr;
template<class T> class enable_shared_from_this;
namespace detail
{
struct static_cast_tag {};
struct const_cast_tag {};
struct dynamic_cast_tag {};
struct polymorphic_cast_tag {};
template<class T> struct shared_ptr_traits
{
typedef T & reference;
};
template<> struct shared_ptr_traits<void>
{
typedef void reference;
};
#if !defined(BOOST_NO_CV_VOID_SPECIALIZATIONS)
template<> struct shared_ptr_traits<void const>
{
typedef void reference;
};
template<> struct shared_ptr_traits<void volatile>
{
typedef void reference;
};
template<> struct shared_ptr_traits<void const volatile>
{
typedef void reference;
};
#endif
// enable_shared_from_this support
template<class T, class Y> void sp_enable_shared_from_this(boost::enable_shared_from_this<T> * pe, Y * px, shared_count const & pn)
{
if(pe != 0) pe->_internal_weak_this._internal_assign(px, pn);
}
inline void sp_enable_shared_from_this(void const volatile *, void const volatile *, shared_count const &)
{
}
} // namespace detail
//
// shared_ptr
//
// An enhanced relative of scoped_ptr with reference counted copy semantics.
// The object pointed to is deleted when the last shared_ptr pointing to it
// is destroyed or reset.
//
template<class T> class shared_ptr
{
private:
// Borland 5.5.1 specific workaround
typedef shared_ptr<T> this_type;
public:
typedef T element_type;
typedef T value_type;
typedef T * pointer;
typedef typename detail::shared_ptr_traits<T>::reference reference;
shared_ptr(): px(0), pn() // never throws in 1.30+
{
}
template<class Y>
explicit shared_ptr(Y * p): px(p), pn(p, checked_deleter<Y>()) // Y must be complete
{
detail::sp_enable_shared_from_this(p, p, pn);
}
//
// Requirements: D's copy constructor must not throw
//
// shared_ptr will release p by calling d(p)
//
template<class Y, class D> shared_ptr(Y * p, D d): px(p), pn(p, d)
{
detail::sp_enable_shared_from_this(p, p, pn);
}
// generated copy constructor, assignment, destructor are fine...
// except that Borland C++ has a bug, and g++ with -Wsynth warns
#if defined(__BORLANDC__) || defined(__GNUC__)
shared_ptr & operator=(shared_ptr const & r) // never throws
{
px = r.px;
pn = r.pn; // shared_count::op= doesn't throw
return *this;
}
#endif
template<class Y>
explicit shared_ptr(weak_ptr<Y> const & r): pn(r.pn) // may throw
{
// it is now safe to copy r.px, as pn(r.pn) did not throw
px = r.px;
}
template<class Y>
shared_ptr(shared_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws
{
}
template<class Y>
shared_ptr(shared_ptr<Y> const & r, detail::static_cast_tag): px(static_cast<element_type *>(r.px)), pn(r.pn)
{
}
template<class Y>
shared_ptr(shared_ptr<Y> const & r, detail::const_cast_tag): px(const_cast<element_type *>(r.px)), pn(r.pn)
{
}
template<class Y>
shared_ptr(shared_ptr<Y> const & r, detail::dynamic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)
{
if(px == 0) // need to allocate new counter -- the cast failed
{
pn = detail::shared_count();
}
}
template<class Y>
shared_ptr(shared_ptr<Y> const & r, detail::polymorphic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)
{
if(px == 0)
{
boost::throw_exception(std::bad_cast());
}
}
#ifndef BOOST_NO_AUTO_PTR
template<class Y>
explicit shared_ptr(std::auto_ptr<Y> & r): px(r.get()), pn()
{
Y * tmp = r.get();
pn = detail::shared_count(r);
detail::sp_enable_shared_from_this(tmp, tmp, pn);
}
#endif
#if !defined(BOOST_MSVC) || (BOOST_MSVC > 1200)
template<class Y>
shared_ptr & operator=(shared_ptr<Y> const & r) // never throws
{
px = r.px;
pn = r.pn; // shared_count::op= doesn't throw
return *this;
}
#endif
#ifndef BOOST_NO_AUTO_PTR
template<class Y>
shared_ptr & operator=(std::auto_ptr<Y> & r)
{
this_type(r).swap(*this);
return *this;
}
#endif
void reset() // never throws in 1.30+
{
this_type().swap(*this);
}
template<class Y> void reset(Y * p) // Y must be complete
{
BOOST_ASSERT(p == 0 || p != px); // catch self-reset errors
this_type(p).swap(*this);
}
template<class Y, class D> void reset(Y * p, D d)
{
this_type(p, d).swap(*this);
}
reference operator* () const // never throws
{
BOOST_ASSERT(px != 0);
return *px;
}
T * operator-> () const // never throws
{
BOOST_ASSERT(px != 0);
return px;
}
T * get() const // never throws
{
return px;
}
// implicit conversion to "bool"
#if defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x530)
operator bool () const
{
return px != 0;
}
#elif defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
typedef T * (this_type::*unspecified_bool_type)() const;
operator unspecified_bool_type() const // never throws
{
return px == 0? 0: &this_type::get;
}
#else
typedef T * this_type::*unspecified_bool_type;
operator unspecified_bool_type() const // never throws
{
return px == 0? 0: &this_type::px;
}
#endif
// operator! is redundant, but some compilers need it
bool operator! () const // never throws
{
return px == 0;
}
bool unique() const // never throws
{
return pn.unique();
}
long use_count() const // never throws
{
return pn.use_count();
}
void swap(shared_ptr<T> & other) // never throws
{
std::swap(px, other.px);
pn.swap(other.pn);
}
template<class Y> bool _internal_less(shared_ptr<Y> const & rhs) const
{
return pn < rhs.pn;
}
void * _internal_get_deleter(std::type_info const & ti) const
{
return pn.get_deleter(ti);
}
// Tasteless as this may seem, making all members public allows member templates
// to work in the absence of member template friends. (Matthew Langston)
#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
private:
template<class Y> friend class shared_ptr;
template<class Y> friend class weak_ptr;
#endif
T * px; // contained pointer
detail::shared_count pn; // reference counter
}; // shared_ptr
template<class T, class U> inline bool operator==(shared_ptr<T> const & a, shared_ptr<U> const & b)
{
return a.get() == b.get();
}
template<class T, class U> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<U> const & b)
{
return a.get() != b.get();
}
#if __GNUC__ == 2 && __GNUC_MINOR__ <= 96
// Resolve the ambiguity between our op!= and the one in rel_ops
template<class T> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<T> const & b)
{
return a.get() != b.get();
}
#endif
template<class T, class U> inline bool operator<(shared_ptr<T> const & a, shared_ptr<U> const & b)
{
return a._internal_less(b);
}
template<class T> inline void swap(shared_ptr<T> & a, shared_ptr<T> & b)
{
a.swap(b);
}
template<class T, class U> shared_ptr<T> static_pointer_cast(shared_ptr<U> const & r)
{
return shared_ptr<T>(r, detail::static_cast_tag());
}
template<class T, class U> shared_ptr<T> const_pointer_cast(shared_ptr<U> const & r)
{
return shared_ptr<T>(r, detail::const_cast_tag());
}
template<class T, class U> shared_ptr<T> dynamic_pointer_cast(shared_ptr<U> const & r)
{
return shared_ptr<T>(r, detail::dynamic_cast_tag());
}
// shared_*_cast names are deprecated. Use *_pointer_cast instead.
template<class T, class U> shared_ptr<T> shared_static_cast(shared_ptr<U> const & r)
{
return shared_ptr<T>(r, detail::static_cast_tag());
}
template<class T, class U> shared_ptr<T> shared_dynamic_cast(shared_ptr<U> const & r)
{
return shared_ptr<T>(r, detail::dynamic_cast_tag());
}
template<class T, class U> shared_ptr<T> shared_polymorphic_cast(shared_ptr<U> const & r)
{
return shared_ptr<T>(r, detail::polymorphic_cast_tag());
}
template<class T, class U> shared_ptr<T> shared_polymorphic_downcast(shared_ptr<U> const & r)
{
BOOST_ASSERT(dynamic_cast<T *>(r.get()) == r.get());
return shared_static_cast<T>(r);
}
// get_pointer() enables boost::mem_fn to recognize shared_ptr
template<class T> inline T * get_pointer(shared_ptr<T> const & p)
{
return p.get();
}
// operator<<
#if defined(__GNUC__) && (__GNUC__ < 3)
template<class Y> std::ostream & operator<< (std::ostream & os, shared_ptr<Y> const & p)
{
os << p.get();
return os;
}
#else
# if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, <= 1200 && __SGI_STL_PORT)
// MSVC6 has problems finding std::basic_ostream through the using declaration in namespace _STL
using std::basic_ostream;
template<class E, class T, class Y> basic_ostream<E, T> & operator<< (basic_ostream<E, T> & os, shared_ptr<Y> const & p)
# else
template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::basic_ostream<E, T> & os, shared_ptr<Y> const & p)
# endif
{
os << p.get();
return os;
}
#endif
// get_deleter (experimental)
#if (defined(__GNUC__) && (__GNUC__ < 3)) || (defined(__EDG_VERSION__) && (__EDG_VERSION__ <= 238))
// g++ 2.9x doesn't allow static_cast<X const *>(void *)
// apparently EDG 2.38 also doesn't accept it
template<class D, class T> D * get_deleter(shared_ptr<T> const & p)
{
void const * q = p._internal_get_deleter(typeid(D));
return const_cast<D *>(static_cast<D const *>(q));
}
#else
template<class D, class T> D * get_deleter(shared_ptr<T> const & p)
{
return static_cast<D *>(p._internal_get_deleter(typeid(D)));
}
#endif
} // namespace boost
#ifdef BOOST_MSVC
# pragma warning(pop)
#endif
#endif // #if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)
#endif // #ifndef BOOST_SHARED_PTR_HPP_INCLUDED