source: NonGTP/Boost/boost/shared_ptr.hpp @ 857

Revision 857, 11.8 KB checked in by igarcia, 19 years ago (diff)
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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, 2002, 2003 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 <boost/assert.hpp>
24#include <boost/checked_delete.hpp>
25#include <boost/throw_exception.hpp>
26#include <boost/detail/shared_count.hpp>
27#include <boost/detail/workaround.hpp>
28
29#include <memory>               // for std::auto_ptr
30#include <algorithm>            // for std::swap
31#include <functional>           // for std::less
32#include <typeinfo>             // for std::bad_cast
33#include <iosfwd>               // for std::basic_ostream
34
35#ifdef BOOST_MSVC  // moved here to work around VC++ compiler crash
36# pragma warning(push)
37# pragma warning(disable:4284) // odd return type for operator->
38#endif
39
40namespace boost
41{
42
43template<class T> class weak_ptr;
44template<class T> class enable_shared_from_this;
45
46namespace detail
47{
48
49struct static_cast_tag {};
50struct const_cast_tag {};
51struct dynamic_cast_tag {};
52struct polymorphic_cast_tag {};
53
54template<class T> struct shared_ptr_traits
55{
56    typedef T & reference;
57};
58
59template<> struct shared_ptr_traits<void>
60{
61    typedef void reference;
62};
63
64#if !defined(BOOST_NO_CV_VOID_SPECIALIZATIONS)
65
66template<> struct shared_ptr_traits<void const>
67{
68    typedef void reference;
69};
70
71template<> struct shared_ptr_traits<void volatile>
72{
73    typedef void reference;
74};
75
76template<> struct shared_ptr_traits<void const volatile>
77{
78    typedef void reference;
79};
80
81#endif
82
83// enable_shared_from_this support
84
85template<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 )
86{
87    if(pe != 0) pe->_internal_weak_this._internal_assign(const_cast<Y*>(px), pn);
88}
89
90inline void sp_enable_shared_from_this( shared_count const & /*pn*/, ... )
91{
92}
93
94} // namespace detail
95
96
97//
98//  shared_ptr
99//
100//  An enhanced relative of scoped_ptr with reference counted copy semantics.
101//  The object pointed to is deleted when the last shared_ptr pointing to it
102//  is destroyed or reset.
103//
104
105template<class T> class shared_ptr
106{
107private:
108
109    // Borland 5.5.1 specific workaround
110    typedef shared_ptr<T> this_type;
111
112public:
113
114    typedef T element_type;
115    typedef T value_type;
116    typedef T * pointer;
117    typedef typename detail::shared_ptr_traits<T>::reference reference;
118
119    shared_ptr(): px(0), pn() // never throws in 1.30+
120    {
121    }
122
123    template<class Y>
124    explicit shared_ptr( Y * p ): px( p ), pn( p ) // Y must be complete
125    {
126        detail::sp_enable_shared_from_this( pn, p, p );
127    }
128
129    //
130    // Requirements: D's copy constructor must not throw
131    //
132    // shared_ptr will release p by calling d(p)
133    //
134
135    template<class Y, class D> shared_ptr(Y * p, D d): px(p), pn(p, d)
136    {
137        detail::sp_enable_shared_from_this( pn, p, p );
138    }
139
140//  generated copy constructor, assignment, destructor are fine...
141
142//  except that Borland C++ has a bug, and g++ with -Wsynth warns
143#if defined(__BORLANDC__) || defined(__GNUC__)
144
145    shared_ptr & operator=(shared_ptr const & r) // never throws
146    {
147        px = r.px;
148        pn = r.pn; // shared_count::op= doesn't throw
149        return *this;
150    }
151
152#endif
153
154    template<class Y>
155    explicit shared_ptr(weak_ptr<Y> const & r): pn(r.pn) // may throw
156    {
157        // it is now safe to copy r.px, as pn(r.pn) did not throw
158        px = r.px;
159    }
160
161    template<class Y>
162    shared_ptr(shared_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws
163    {
164    }
165
166    template<class Y>
167    shared_ptr(shared_ptr<Y> const & r, detail::static_cast_tag): px(static_cast<element_type *>(r.px)), pn(r.pn)
168    {
169    }
170
171    template<class Y>
172    shared_ptr(shared_ptr<Y> const & r, detail::const_cast_tag): px(const_cast<element_type *>(r.px)), pn(r.pn)
173    {
174    }
175
176    template<class Y>
177    shared_ptr(shared_ptr<Y> const & r, detail::dynamic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)
178    {
179        if(px == 0) // need to allocate new counter -- the cast failed
180        {
181            pn = detail::shared_count();
182        }
183    }
184
185    template<class Y>
186    shared_ptr(shared_ptr<Y> const & r, detail::polymorphic_cast_tag): px(dynamic_cast<element_type *>(r.px)), pn(r.pn)
187    {
188        if(px == 0)
189        {
190            boost::throw_exception(std::bad_cast());
191        }
192    }
193
194#ifndef BOOST_NO_AUTO_PTR
195
196    template<class Y>
197    explicit shared_ptr(std::auto_ptr<Y> & r): px(r.get()), pn()
198    {
199        Y * tmp = r.get();
200        pn = detail::shared_count(r);
201        detail::sp_enable_shared_from_this( pn, tmp, tmp );
202    }
203
204#endif
205
206#if !defined(BOOST_MSVC) || (BOOST_MSVC > 1200)
207
208    template<class Y>
209    shared_ptr & operator=(shared_ptr<Y> const & r) // never throws
210    {
211        px = r.px;
212        pn = r.pn; // shared_count::op= doesn't throw
213        return *this;
214    }
215
216#endif
217
218#ifndef BOOST_NO_AUTO_PTR
219
220    template<class Y>
221    shared_ptr & operator=(std::auto_ptr<Y> & r)
222    {
223        this_type(r).swap(*this);
224        return *this;
225    }
226
227#endif
228
229    void reset() // never throws in 1.30+
230    {
231        this_type().swap(*this);
232    }
233
234    template<class Y> void reset(Y * p) // Y must be complete
235    {
236        BOOST_ASSERT(p == 0 || p != px); // catch self-reset errors
237        this_type(p).swap(*this);
238    }
239
240    template<class Y, class D> void reset(Y * p, D d)
241    {
242        this_type(p, d).swap(*this);
243    }
244
245    reference operator* () const // never throws
246    {
247        BOOST_ASSERT(px != 0);
248        return *px;
249    }
250
251    T * operator-> () const // never throws
252    {
253        BOOST_ASSERT(px != 0);
254        return px;
255    }
256   
257    T * get() const // never throws
258    {
259        return px;
260    }
261
262    // implicit conversion to "bool"
263
264#if defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x530)
265
266    operator bool () const
267    {
268        return px != 0;
269    }
270
271#elif \
272    ( defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, < 0x3200) ) || \
273    ( defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ < 304) )
274
275    typedef T * (this_type::*unspecified_bool_type)() const;
276   
277    operator unspecified_bool_type() const // never throws
278    {
279        return px == 0? 0: &this_type::get;
280    }
281
282#else
283
284    typedef T * this_type::*unspecified_bool_type;
285
286    operator unspecified_bool_type() const // never throws
287    {
288        return px == 0? 0: &this_type::px;
289    }
290
291#endif
292
293    // operator! is redundant, but some compilers need it
294
295    bool operator! () const // never throws
296    {
297        return px == 0;
298    }
299
300    bool unique() const // never throws
301    {
302        return pn.unique();
303    }
304
305    long use_count() const // never throws
306    {
307        return pn.use_count();
308    }
309
310    void swap(shared_ptr<T> & other) // never throws
311    {
312        std::swap(px, other.px);
313        pn.swap(other.pn);
314    }
315
316    template<class Y> bool _internal_less(shared_ptr<Y> const & rhs) const
317    {
318        return pn < rhs.pn;
319    }
320
321    void * _internal_get_deleter(std::type_info const & ti) const
322    {
323        return pn.get_deleter(ti);
324    }
325
326// Tasteless as this may seem, making all members public allows member templates
327// to work in the absence of member template friends. (Matthew Langston)
328
329#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
330
331private:
332
333    template<class Y> friend class shared_ptr;
334    template<class Y> friend class weak_ptr;
335
336
337#endif
338
339    T * px;                     // contained pointer
340    detail::shared_count pn;    // reference counter
341
342};  // shared_ptr
343
344template<class T, class U> inline bool operator==(shared_ptr<T> const & a, shared_ptr<U> const & b)
345{
346    return a.get() == b.get();
347}
348
349template<class T, class U> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<U> const & b)
350{
351    return a.get() != b.get();
352}
353
354#if __GNUC__ == 2 && __GNUC_MINOR__ <= 96
355
356// Resolve the ambiguity between our op!= and the one in rel_ops
357
358template<class T> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<T> const & b)
359{
360    return a.get() != b.get();
361}
362
363#endif
364
365template<class T, class U> inline bool operator<(shared_ptr<T> const & a, shared_ptr<U> const & b)
366{
367    return a._internal_less(b);
368}
369
370template<class T> inline void swap(shared_ptr<T> & a, shared_ptr<T> & b)
371{
372    a.swap(b);
373}
374
375template<class T, class U> shared_ptr<T> static_pointer_cast(shared_ptr<U> const & r)
376{
377    return shared_ptr<T>(r, detail::static_cast_tag());
378}
379
380template<class T, class U> shared_ptr<T> const_pointer_cast(shared_ptr<U> const & r)
381{
382    return shared_ptr<T>(r, detail::const_cast_tag());
383}
384
385template<class T, class U> shared_ptr<T> dynamic_pointer_cast(shared_ptr<U> const & r)
386{
387    return shared_ptr<T>(r, detail::dynamic_cast_tag());
388}
389
390// shared_*_cast names are deprecated. Use *_pointer_cast instead.
391
392template<class T, class U> shared_ptr<T> shared_static_cast(shared_ptr<U> const & r)
393{
394    return shared_ptr<T>(r, detail::static_cast_tag());
395}
396
397template<class T, class U> shared_ptr<T> shared_dynamic_cast(shared_ptr<U> const & r)
398{
399    return shared_ptr<T>(r, detail::dynamic_cast_tag());
400}
401
402template<class T, class U> shared_ptr<T> shared_polymorphic_cast(shared_ptr<U> const & r)
403{
404    return shared_ptr<T>(r, detail::polymorphic_cast_tag());
405}
406
407template<class T, class U> shared_ptr<T> shared_polymorphic_downcast(shared_ptr<U> const & r)
408{
409    BOOST_ASSERT(dynamic_cast<T *>(r.get()) == r.get());
410    return shared_static_cast<T>(r);
411}
412
413// get_pointer() enables boost::mem_fn to recognize shared_ptr
414
415template<class T> inline T * get_pointer(shared_ptr<T> const & p)
416{
417    return p.get();
418}
419
420// operator<<
421
422#if defined(__GNUC__) &&  (__GNUC__ < 3)
423
424template<class Y> std::ostream & operator<< (std::ostream & os, shared_ptr<Y> const & p)
425{
426    os << p.get();
427    return os;
428}
429
430#else
431
432# if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, <= 1200 && __SGI_STL_PORT)
433// MSVC6 has problems finding std::basic_ostream through the using declaration in namespace _STL
434using std::basic_ostream;
435template<class E, class T, class Y> basic_ostream<E, T> & operator<< (basic_ostream<E, T> & os, shared_ptr<Y> const & p)
436# else
437template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::basic_ostream<E, T> & os, shared_ptr<Y> const & p)
438# endif
439{
440    os << p.get();
441    return os;
442}
443
444#endif
445
446// get_deleter (experimental)
447
448#if ( defined(__GNUC__) && BOOST_WORKAROUND(__GNUC__, < 3) ) || \
449    ( defined(__EDG_VERSION__) && BOOST_WORKAROUND(__EDG_VERSION__, <= 238) ) || \
450    ( defined(__HP_aCC) && BOOST_WORKAROUND(__HP_aCC, <= 33500) )
451
452// g++ 2.9x doesn't allow static_cast<X const *>(void *)
453// apparently EDG 2.38 and HP aCC A.03.35 also don't accept it
454
455template<class D, class T> D * get_deleter(shared_ptr<T> const & p)
456{
457    void const * q = p._internal_get_deleter(typeid(D));
458    return const_cast<D *>(static_cast<D const *>(q));
459}
460
461#else
462
463template<class D, class T> D * get_deleter(shared_ptr<T> const & p)
464{
465    return static_cast<D *>(p._internal_get_deleter(typeid(D)));
466}
467
468#endif
469
470} // namespace boost
471
472#ifdef BOOST_MSVC
473# pragma warning(pop)
474#endif   
475
476#endif  // #if defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES)
477
478#endif  // #ifndef BOOST_SHARED_PTR_HPP_INCLUDED
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