libstdc++
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00001 // shared_ptr and weak_ptr implementation -*- C++ -*- 00002 00003 // Copyright (C) 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 // GCC Note: Based on files from version 1.32.0 of the Boost library. 00026 00027 // shared_count.hpp 00028 // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. 00029 00030 // shared_ptr.hpp 00031 // Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes. 00032 // Copyright (C) 2001, 2002, 2003 Peter Dimov 00033 00034 // weak_ptr.hpp 00035 // Copyright (C) 2001, 2002, 2003 Peter Dimov 00036 00037 // enable_shared_from_this.hpp 00038 // Copyright (C) 2002 Peter Dimov 00039 00040 // Distributed under the Boost Software License, Version 1.0. (See 00041 // accompanying file LICENSE_1_0.txt or copy at 00042 // http://www.boost.org/LICENSE_1_0.txt) 00043 00044 /** @file bits/shared_ptr.h 00045 * This is an internal header file, included by other library headers. 00046 * Do not attempt to use it directly. @headername{memory} 00047 */ 00048 00049 #ifndef _SHARED_PTR_H 00050 #define _SHARED_PTR_H 1 00051 00052 #include <bits/shared_ptr_base.h> 00053 00054 namespace std _GLIBCXX_VISIBILITY(default) 00055 { 00056 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00057 00058 /** 00059 * @addtogroup pointer_abstractions 00060 * @{ 00061 */ 00062 00063 /// 2.2.3.7 shared_ptr I/O 00064 template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp> 00065 inline std::basic_ostream<_Ch, _Tr>& 00066 operator<<(std::basic_ostream<_Ch, _Tr>& __os, 00067 const __shared_ptr<_Tp, _Lp>& __p) 00068 { 00069 __os << __p.get(); 00070 return __os; 00071 } 00072 00073 /// 2.2.3.10 shared_ptr get_deleter (experimental) 00074 template<typename _Del, typename _Tp, _Lock_policy _Lp> 00075 inline _Del* 00076 get_deleter(const __shared_ptr<_Tp, _Lp>& __p) 00077 { 00078 #ifdef __GXX_RTTI 00079 return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); 00080 #else 00081 return 0; 00082 #endif 00083 } 00084 00085 00086 /** 00087 * @brief A smart pointer with reference-counted copy semantics. 00088 * 00089 * The object pointed to is deleted when the last shared_ptr pointing to 00090 * it is destroyed or reset. 00091 */ 00092 template<typename _Tp> 00093 class shared_ptr : public __shared_ptr<_Tp> 00094 { 00095 public: 00096 /** 00097 * @brief Construct an empty %shared_ptr. 00098 * @post use_count()==0 && get()==0 00099 */ 00100 constexpr shared_ptr() 00101 : __shared_ptr<_Tp>() { } 00102 00103 /** 00104 * @brief Construct a %shared_ptr that owns the pointer @a __p. 00105 * @param __p A pointer that is convertible to element_type*. 00106 * @post use_count() == 1 && get() == __p 00107 * @throw std::bad_alloc, in which case @c delete @a __p is called. 00108 */ 00109 template<typename _Tp1> 00110 explicit shared_ptr(_Tp1* __p) 00111 : __shared_ptr<_Tp>(__p) { } 00112 00113 /** 00114 * @brief Construct a %shared_ptr that owns the pointer @a __p 00115 * and the deleter @a __d. 00116 * @param __p A pointer. 00117 * @param __d A deleter. 00118 * @post use_count() == 1 && get() == __p 00119 * @throw std::bad_alloc, in which case @a __d(__p) is called. 00120 * 00121 * Requirements: _Deleter's copy constructor and destructor must 00122 * not throw 00123 * 00124 * __shared_ptr will release __p by calling __d(__p) 00125 */ 00126 template<typename _Tp1, typename _Deleter> 00127 shared_ptr(_Tp1* __p, _Deleter __d) 00128 : __shared_ptr<_Tp>(__p, __d) { } 00129 00130 /** 00131 * @brief Construct a %shared_ptr that owns a null pointer 00132 * and the deleter @a __d. 00133 * @param __p A null pointer constant. 00134 * @param __d A deleter. 00135 * @post use_count() == 1 && get() == __p 00136 * @throw std::bad_alloc, in which case @a __d(__p) is called. 00137 * 00138 * Requirements: _Deleter's copy constructor and destructor must 00139 * not throw 00140 * 00141 * The last owner will call __d(__p) 00142 */ 00143 template<typename _Deleter> 00144 shared_ptr(nullptr_t __p, _Deleter __d) 00145 : __shared_ptr<_Tp>(__p, __d) { } 00146 00147 /** 00148 * @brief Construct a %shared_ptr that owns the pointer @a __p 00149 * and the deleter @a __d. 00150 * @param __p A pointer. 00151 * @param __d A deleter. 00152 * @param __a An allocator. 00153 * @post use_count() == 1 && get() == __p 00154 * @throw std::bad_alloc, in which case @a __d(__p) is called. 00155 * 00156 * Requirements: _Deleter's copy constructor and destructor must 00157 * not throw _Alloc's copy constructor and destructor must not 00158 * throw. 00159 * 00160 * __shared_ptr will release __p by calling __d(__p) 00161 */ 00162 template<typename _Tp1, typename _Deleter, typename _Alloc> 00163 shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a) 00164 : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { } 00165 00166 /** 00167 * @brief Construct a %shared_ptr that owns a null pointer 00168 * and the deleter @a __d. 00169 * @param __p A null pointer constant. 00170 * @param __d A deleter. 00171 * @param __a An allocator. 00172 * @post use_count() == 1 && get() == __p 00173 * @throw std::bad_alloc, in which case @a __d(__p) is called. 00174 * 00175 * Requirements: _Deleter's copy constructor and destructor must 00176 * not throw _Alloc's copy constructor and destructor must not 00177 * throw. 00178 * 00179 * The last owner will call __d(__p) 00180 */ 00181 template<typename _Deleter, typename _Alloc> 00182 shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a) 00183 : __shared_ptr<_Tp>(__p, __d, std::move(__a)) { } 00184 00185 // Aliasing constructor 00186 00187 /** 00188 * @brief Constructs a %shared_ptr instance that stores @a __p 00189 * and shares ownership with @a __r. 00190 * @param __r A %shared_ptr. 00191 * @param __p A pointer that will remain valid while @a *__r is valid. 00192 * @post get() == __p && use_count() == __r.use_count() 00193 * 00194 * This can be used to construct a @c shared_ptr to a sub-object 00195 * of an object managed by an existing @c shared_ptr. 00196 * 00197 * @code 00198 * shared_ptr< pair<int,int> > pii(new pair<int,int>()); 00199 * shared_ptr<int> pi(pii, &pii->first); 00200 * assert(pii.use_count() == 2); 00201 * @endcode 00202 */ 00203 template<typename _Tp1> 00204 shared_ptr(const shared_ptr<_Tp1>& __r, _Tp* __p) 00205 : __shared_ptr<_Tp>(__r, __p) { } 00206 00207 /** 00208 * @brief If @a __r is empty, constructs an empty %shared_ptr; 00209 * otherwise construct a %shared_ptr that shares ownership 00210 * with @a __r. 00211 * @param __r A %shared_ptr. 00212 * @post get() == __r.get() && use_count() == __r.use_count() 00213 */ 00214 template<typename _Tp1, typename = typename 00215 std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> 00216 shared_ptr(const shared_ptr<_Tp1>& __r) 00217 : __shared_ptr<_Tp>(__r) { } 00218 00219 /** 00220 * @brief Move-constructs a %shared_ptr instance from @a __r. 00221 * @param __r A %shared_ptr rvalue. 00222 * @post *this contains the old value of @a __r, @a __r is empty. 00223 */ 00224 shared_ptr(shared_ptr&& __r) 00225 : __shared_ptr<_Tp>(std::move(__r)) { } 00226 00227 /** 00228 * @brief Move-constructs a %shared_ptr instance from @a __r. 00229 * @param __r A %shared_ptr rvalue. 00230 * @post *this contains the old value of @a __r, @a __r is empty. 00231 */ 00232 template<typename _Tp1, typename = typename 00233 std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> 00234 shared_ptr(shared_ptr<_Tp1>&& __r) 00235 : __shared_ptr<_Tp>(std::move(__r)) { } 00236 00237 /** 00238 * @brief Constructs a %shared_ptr that shares ownership with @a __r 00239 * and stores a copy of the pointer stored in @a __r. 00240 * @param __r A weak_ptr. 00241 * @post use_count() == __r.use_count() 00242 * @throw bad_weak_ptr when __r.expired(), 00243 * in which case the constructor has no effect. 00244 */ 00245 template<typename _Tp1> 00246 explicit shared_ptr(const weak_ptr<_Tp1>& __r) 00247 : __shared_ptr<_Tp>(__r) { } 00248 00249 #if _GLIBCXX_USE_DEPRECATED 00250 template<typename _Tp1> 00251 shared_ptr(std::auto_ptr<_Tp1>&& __r) 00252 : __shared_ptr<_Tp>(std::move(__r)) { } 00253 #endif 00254 00255 template<typename _Tp1, typename _Del> 00256 shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r) 00257 : __shared_ptr<_Tp>(std::move(__r)) { } 00258 00259 /** 00260 * @brief Construct an empty %shared_ptr. 00261 * @param __p A null pointer constant. 00262 * @post use_count() == 0 && get() == nullptr 00263 */ 00264 constexpr shared_ptr(nullptr_t __p) 00265 : __shared_ptr<_Tp>(__p) { } 00266 00267 template<typename _Tp1> 00268 shared_ptr& 00269 operator=(const shared_ptr<_Tp1>& __r) // never throws 00270 { 00271 this->__shared_ptr<_Tp>::operator=(__r); 00272 return *this; 00273 } 00274 00275 #if _GLIBCXX_USE_DEPRECATED 00276 template<typename _Tp1> 00277 shared_ptr& 00278 operator=(std::auto_ptr<_Tp1>&& __r) 00279 { 00280 this->__shared_ptr<_Tp>::operator=(std::move(__r)); 00281 return *this; 00282 } 00283 #endif 00284 00285 shared_ptr& 00286 operator=(shared_ptr&& __r) 00287 { 00288 this->__shared_ptr<_Tp>::operator=(std::move(__r)); 00289 return *this; 00290 } 00291 00292 template<class _Tp1> 00293 shared_ptr& 00294 operator=(shared_ptr<_Tp1>&& __r) 00295 { 00296 this->__shared_ptr<_Tp>::operator=(std::move(__r)); 00297 return *this; 00298 } 00299 00300 template<typename _Tp1, typename _Del> 00301 shared_ptr& 00302 operator=(std::unique_ptr<_Tp1, _Del>&& __r) 00303 { 00304 this->__shared_ptr<_Tp>::operator=(std::move(__r)); 00305 return *this; 00306 } 00307 00308 private: 00309 // This constructor is non-standard, it is used by allocate_shared. 00310 template<typename _Alloc, typename... _Args> 00311 shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a, 00312 _Args&&... __args) 00313 : __shared_ptr<_Tp>(__tag, __a, std::forward<_Args>(__args)...) 00314 { } 00315 00316 template<typename _Tp1, typename _Alloc, typename... _Args> 00317 friend shared_ptr<_Tp1> 00318 allocate_shared(const _Alloc& __a, _Args&&... __args); 00319 }; 00320 00321 // 20.8.13.2.7 shared_ptr comparisons 00322 template<typename _Tp1, typename _Tp2> 00323 inline bool 00324 operator==(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b) 00325 { return __a.get() == __b.get(); } 00326 00327 template<typename _Tp> 00328 inline bool 00329 operator==(const shared_ptr<_Tp>& __a, nullptr_t) 00330 { return __a.get() == nullptr; } 00331 00332 template<typename _Tp> 00333 inline bool 00334 operator==(nullptr_t, const shared_ptr<_Tp>& __b) 00335 { return nullptr == __b.get(); } 00336 00337 template<typename _Tp1, typename _Tp2> 00338 inline bool 00339 operator!=(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b) 00340 { return __a.get() != __b.get(); } 00341 00342 template<typename _Tp> 00343 inline bool 00344 operator!=(const shared_ptr<_Tp>& __a, nullptr_t) 00345 { return __a.get() != nullptr; } 00346 00347 template<typename _Tp> 00348 inline bool 00349 operator!=(nullptr_t, const shared_ptr<_Tp>& __b) 00350 { return nullptr != __b.get(); } 00351 00352 template<typename _Tp1, typename _Tp2> 00353 inline bool 00354 operator<(const shared_ptr<_Tp1>& __a, const shared_ptr<_Tp2>& __b) 00355 { return __a.get() < __b.get(); } 00356 00357 template<typename _Tp> 00358 struct less<shared_ptr<_Tp>> : public _Sp_less<shared_ptr<_Tp>> 00359 { }; 00360 00361 // 20.8.13.2.9 shared_ptr specialized algorithms. 00362 template<typename _Tp> 00363 inline void 00364 swap(shared_ptr<_Tp>& __a, shared_ptr<_Tp>& __b) 00365 { __a.swap(__b); } 00366 00367 // 20.8.13.2.10 shared_ptr casts. 00368 template<typename _Tp, typename _Tp1> 00369 inline shared_ptr<_Tp> 00370 static_pointer_cast(const shared_ptr<_Tp1>& __r) 00371 { return shared_ptr<_Tp>(__r, static_cast<_Tp*>(__r.get())); } 00372 00373 template<typename _Tp, typename _Tp1> 00374 inline shared_ptr<_Tp> 00375 const_pointer_cast(const shared_ptr<_Tp1>& __r) 00376 { return shared_ptr<_Tp>(__r, const_cast<_Tp*>(__r.get())); } 00377 00378 template<typename _Tp, typename _Tp1> 00379 inline shared_ptr<_Tp> 00380 dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) 00381 { 00382 if (_Tp* __p = dynamic_cast<_Tp*>(__r.get())) 00383 return shared_ptr<_Tp>(__r, __p); 00384 return shared_ptr<_Tp>(); 00385 } 00386 00387 00388 /** 00389 * @brief A smart pointer with weak semantics. 00390 * 00391 * With forwarding constructors and assignment operators. 00392 */ 00393 template<typename _Tp> 00394 class weak_ptr : public __weak_ptr<_Tp> 00395 { 00396 public: 00397 constexpr weak_ptr() 00398 : __weak_ptr<_Tp>() { } 00399 00400 template<typename _Tp1, typename = typename 00401 std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> 00402 weak_ptr(const weak_ptr<_Tp1>& __r) 00403 : __weak_ptr<_Tp>(__r) { } 00404 00405 template<typename _Tp1, typename = typename 00406 std::enable_if<std::is_convertible<_Tp1*, _Tp*>::value>::type> 00407 weak_ptr(const shared_ptr<_Tp1>& __r) 00408 : __weak_ptr<_Tp>(__r) { } 00409 00410 template<typename _Tp1> 00411 weak_ptr& 00412 operator=(const weak_ptr<_Tp1>& __r) // never throws 00413 { 00414 this->__weak_ptr<_Tp>::operator=(__r); 00415 return *this; 00416 } 00417 00418 template<typename _Tp1> 00419 weak_ptr& 00420 operator=(const shared_ptr<_Tp1>& __r) // never throws 00421 { 00422 this->__weak_ptr<_Tp>::operator=(__r); 00423 return *this; 00424 } 00425 00426 shared_ptr<_Tp> 00427 lock() const // never throws 00428 { 00429 #ifdef __GTHREADS 00430 if (this->expired()) 00431 return shared_ptr<_Tp>(); 00432 00433 __try 00434 { 00435 return shared_ptr<_Tp>(*this); 00436 } 00437 __catch(const bad_weak_ptr&) 00438 { 00439 return shared_ptr<_Tp>(); 00440 } 00441 #else 00442 return this->expired() ? shared_ptr<_Tp>() : shared_ptr<_Tp>(*this); 00443 #endif 00444 } 00445 }; 00446 00447 // 20.8.13.3.7 weak_ptr specialized algorithms. 00448 template<typename _Tp> 00449 inline void 00450 swap(weak_ptr<_Tp>& __a, weak_ptr<_Tp>& __b) 00451 { __a.swap(__b); } 00452 00453 00454 /// Primary template owner_less 00455 template<typename _Tp> 00456 struct owner_less; 00457 00458 /// Partial specialization of owner_less for shared_ptr. 00459 template<typename _Tp> 00460 struct owner_less<shared_ptr<_Tp>> 00461 : public _Sp_owner_less<shared_ptr<_Tp>, weak_ptr<_Tp>> 00462 { }; 00463 00464 /// Partial specialization of owner_less for weak_ptr. 00465 template<typename _Tp> 00466 struct owner_less<weak_ptr<_Tp>> 00467 : public _Sp_owner_less<weak_ptr<_Tp>, shared_ptr<_Tp>> 00468 { }; 00469 00470 /** 00471 * @brief Base class allowing use of member function shared_from_this. 00472 */ 00473 template<typename _Tp> 00474 class enable_shared_from_this 00475 { 00476 protected: 00477 constexpr enable_shared_from_this() { } 00478 00479 enable_shared_from_this(const enable_shared_from_this&) { } 00480 00481 enable_shared_from_this& 00482 operator=(const enable_shared_from_this&) 00483 { return *this; } 00484 00485 ~enable_shared_from_this() { } 00486 00487 public: 00488 shared_ptr<_Tp> 00489 shared_from_this() 00490 { return shared_ptr<_Tp>(this->_M_weak_this); } 00491 00492 shared_ptr<const _Tp> 00493 shared_from_this() const 00494 { return shared_ptr<const _Tp>(this->_M_weak_this); } 00495 00496 private: 00497 template<typename _Tp1> 00498 void 00499 _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const 00500 { _M_weak_this._M_assign(__p, __n); } 00501 00502 template<typename _Tp1> 00503 friend void 00504 __enable_shared_from_this_helper(const __shared_count<>& __pn, 00505 const enable_shared_from_this* __pe, 00506 const _Tp1* __px) 00507 { 00508 if (__pe != 0) 00509 __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn); 00510 } 00511 00512 mutable weak_ptr<_Tp> _M_weak_this; 00513 }; 00514 00515 /** 00516 * @brief Create an object that is owned by a shared_ptr. 00517 * @param __a An allocator. 00518 * @param __args Arguments for the @a _Tp object's constructor. 00519 * @return A shared_ptr that owns the newly created object. 00520 * @throw An exception thrown from @a _Alloc::allocate or from the 00521 * constructor of @a _Tp. 00522 * 00523 * A copy of @a __a will be used to allocate memory for the shared_ptr 00524 * and the new object. 00525 */ 00526 template<typename _Tp, typename _Alloc, typename... _Args> 00527 inline shared_ptr<_Tp> 00528 allocate_shared(const _Alloc& __a, _Args&&... __args) 00529 { 00530 return shared_ptr<_Tp>(_Sp_make_shared_tag(), __a, 00531 std::forward<_Args>(__args)...); 00532 } 00533 00534 /** 00535 * @brief Create an object that is owned by a shared_ptr. 00536 * @param __args Arguments for the @a _Tp object's constructor. 00537 * @return A shared_ptr that owns the newly created object. 00538 * @throw std::bad_alloc, or an exception thrown from the 00539 * constructor of @a _Tp. 00540 */ 00541 template<typename _Tp, typename... _Args> 00542 inline shared_ptr<_Tp> 00543 make_shared(_Args&&... __args) 00544 { 00545 typedef typename std::remove_const<_Tp>::type _Tp_nc; 00546 return allocate_shared<_Tp>(std::allocator<_Tp_nc>(), 00547 std::forward<_Args>(__args)...); 00548 } 00549 00550 /// std::hash specialization for shared_ptr. 00551 template<typename _Tp> 00552 struct hash<shared_ptr<_Tp>> 00553 : public std::unary_function<shared_ptr<_Tp>, size_t> 00554 { 00555 size_t 00556 operator()(const shared_ptr<_Tp>& __s) const 00557 { return std::hash<_Tp*>()(__s.get()); } 00558 }; 00559 00560 // @} group pointer_abstractions 00561 00562 _GLIBCXX_END_NAMESPACE_VERSION 00563 } // namespace 00564 00565 #endif // _SHARED_PTR_H