libstdc++
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00001 // shared_ptr and weak_ptr implementation details -*- C++ -*- 00002 00003 // Copyright (C) 2007-2017 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_base.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_BASE_H 00050 #define _SHARED_PTR_BASE_H 1 00051 00052 #if __cpp_rtti 00053 # include <typeinfo> 00054 #endif 00055 #include <bits/allocated_ptr.h> 00056 #include <bits/refwrap.h> 00057 #include <bits/stl_function.h> 00058 #include <ext/aligned_buffer.h> 00059 00060 namespace std _GLIBCXX_VISIBILITY(default) 00061 { 00062 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00063 00064 #if _GLIBCXX_USE_DEPRECATED 00065 template<typename> class auto_ptr; 00066 #endif 00067 00068 /** 00069 * @brief Exception possibly thrown by @c shared_ptr. 00070 * @ingroup exceptions 00071 */ 00072 class bad_weak_ptr : public std::exception 00073 { 00074 public: 00075 virtual char const* what() const noexcept; 00076 00077 virtual ~bad_weak_ptr() noexcept; 00078 }; 00079 00080 // Substitute for bad_weak_ptr object in the case of -fno-exceptions. 00081 inline void 00082 __throw_bad_weak_ptr() 00083 { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); } 00084 00085 using __gnu_cxx::_Lock_policy; 00086 using __gnu_cxx::__default_lock_policy; 00087 using __gnu_cxx::_S_single; 00088 using __gnu_cxx::_S_mutex; 00089 using __gnu_cxx::_S_atomic; 00090 00091 // Empty helper class except when the template argument is _S_mutex. 00092 template<_Lock_policy _Lp> 00093 class _Mutex_base 00094 { 00095 protected: 00096 // The atomic policy uses fully-fenced builtins, single doesn't care. 00097 enum { _S_need_barriers = 0 }; 00098 }; 00099 00100 template<> 00101 class _Mutex_base<_S_mutex> 00102 : public __gnu_cxx::__mutex 00103 { 00104 protected: 00105 // This policy is used when atomic builtins are not available. 00106 // The replacement atomic operations might not have the necessary 00107 // memory barriers. 00108 enum { _S_need_barriers = 1 }; 00109 }; 00110 00111 template<_Lock_policy _Lp = __default_lock_policy> 00112 class _Sp_counted_base 00113 : public _Mutex_base<_Lp> 00114 { 00115 public: 00116 _Sp_counted_base() noexcept 00117 : _M_use_count(1), _M_weak_count(1) { } 00118 00119 virtual 00120 ~_Sp_counted_base() noexcept 00121 { } 00122 00123 // Called when _M_use_count drops to zero, to release the resources 00124 // managed by *this. 00125 virtual void 00126 _M_dispose() noexcept = 0; 00127 00128 // Called when _M_weak_count drops to zero. 00129 virtual void 00130 _M_destroy() noexcept 00131 { delete this; } 00132 00133 virtual void* 00134 _M_get_deleter(const std::type_info&) noexcept = 0; 00135 00136 void 00137 _M_add_ref_copy() 00138 { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); } 00139 00140 void 00141 _M_add_ref_lock(); 00142 00143 bool 00144 _M_add_ref_lock_nothrow(); 00145 00146 void 00147 _M_release() noexcept 00148 { 00149 // Be race-detector-friendly. For more info see bits/c++config. 00150 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count); 00151 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1) 00152 { 00153 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count); 00154 _M_dispose(); 00155 // There must be a memory barrier between dispose() and destroy() 00156 // to ensure that the effects of dispose() are observed in the 00157 // thread that runs destroy(). 00158 // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html 00159 if (_Mutex_base<_Lp>::_S_need_barriers) 00160 { 00161 __atomic_thread_fence (__ATOMIC_ACQ_REL); 00162 } 00163 00164 // Be race-detector-friendly. For more info see bits/c++config. 00165 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); 00166 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, 00167 -1) == 1) 00168 { 00169 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); 00170 _M_destroy(); 00171 } 00172 } 00173 } 00174 00175 void 00176 _M_weak_add_ref() noexcept 00177 { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); } 00178 00179 void 00180 _M_weak_release() noexcept 00181 { 00182 // Be race-detector-friendly. For more info see bits/c++config. 00183 _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); 00184 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1) 00185 { 00186 _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); 00187 if (_Mutex_base<_Lp>::_S_need_barriers) 00188 { 00189 // See _M_release(), 00190 // destroy() must observe results of dispose() 00191 __atomic_thread_fence (__ATOMIC_ACQ_REL); 00192 } 00193 _M_destroy(); 00194 } 00195 } 00196 00197 long 00198 _M_get_use_count() const noexcept 00199 { 00200 // No memory barrier is used here so there is no synchronization 00201 // with other threads. 00202 return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED); 00203 } 00204 00205 private: 00206 _Sp_counted_base(_Sp_counted_base const&) = delete; 00207 _Sp_counted_base& operator=(_Sp_counted_base const&) = delete; 00208 00209 _Atomic_word _M_use_count; // #shared 00210 _Atomic_word _M_weak_count; // #weak + (#shared != 0) 00211 }; 00212 00213 template<> 00214 inline void 00215 _Sp_counted_base<_S_single>:: 00216 _M_add_ref_lock() 00217 { 00218 if (_M_use_count == 0) 00219 __throw_bad_weak_ptr(); 00220 ++_M_use_count; 00221 } 00222 00223 template<> 00224 inline void 00225 _Sp_counted_base<_S_mutex>:: 00226 _M_add_ref_lock() 00227 { 00228 __gnu_cxx::__scoped_lock sentry(*this); 00229 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0) 00230 { 00231 _M_use_count = 0; 00232 __throw_bad_weak_ptr(); 00233 } 00234 } 00235 00236 template<> 00237 inline void 00238 _Sp_counted_base<_S_atomic>:: 00239 _M_add_ref_lock() 00240 { 00241 // Perform lock-free add-if-not-zero operation. 00242 _Atomic_word __count = _M_get_use_count(); 00243 do 00244 { 00245 if (__count == 0) 00246 __throw_bad_weak_ptr(); 00247 // Replace the current counter value with the old value + 1, as 00248 // long as it's not changed meanwhile. 00249 } 00250 while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1, 00251 true, __ATOMIC_ACQ_REL, 00252 __ATOMIC_RELAXED)); 00253 } 00254 00255 template<> 00256 inline bool 00257 _Sp_counted_base<_S_single>:: 00258 _M_add_ref_lock_nothrow() 00259 { 00260 if (_M_use_count == 0) 00261 return false; 00262 ++_M_use_count; 00263 return true; 00264 } 00265 00266 template<> 00267 inline bool 00268 _Sp_counted_base<_S_mutex>:: 00269 _M_add_ref_lock_nothrow() 00270 { 00271 __gnu_cxx::__scoped_lock sentry(*this); 00272 if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0) 00273 { 00274 _M_use_count = 0; 00275 return false; 00276 } 00277 return true; 00278 } 00279 00280 template<> 00281 inline bool 00282 _Sp_counted_base<_S_atomic>:: 00283 _M_add_ref_lock_nothrow() 00284 { 00285 // Perform lock-free add-if-not-zero operation. 00286 _Atomic_word __count = _M_get_use_count(); 00287 do 00288 { 00289 if (__count == 0) 00290 return false; 00291 // Replace the current counter value with the old value + 1, as 00292 // long as it's not changed meanwhile. 00293 } 00294 while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1, 00295 true, __ATOMIC_ACQ_REL, 00296 __ATOMIC_RELAXED)); 00297 return true; 00298 } 00299 00300 template<> 00301 inline void 00302 _Sp_counted_base<_S_single>::_M_add_ref_copy() 00303 { ++_M_use_count; } 00304 00305 template<> 00306 inline void 00307 _Sp_counted_base<_S_single>::_M_release() noexcept 00308 { 00309 if (--_M_use_count == 0) 00310 { 00311 _M_dispose(); 00312 if (--_M_weak_count == 0) 00313 _M_destroy(); 00314 } 00315 } 00316 00317 template<> 00318 inline void 00319 _Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept 00320 { ++_M_weak_count; } 00321 00322 template<> 00323 inline void 00324 _Sp_counted_base<_S_single>::_M_weak_release() noexcept 00325 { 00326 if (--_M_weak_count == 0) 00327 _M_destroy(); 00328 } 00329 00330 template<> 00331 inline long 00332 _Sp_counted_base<_S_single>::_M_get_use_count() const noexcept 00333 { return _M_use_count; } 00334 00335 00336 // Forward declarations. 00337 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> 00338 class __shared_ptr; 00339 00340 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> 00341 class __weak_ptr; 00342 00343 template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> 00344 class __enable_shared_from_this; 00345 00346 template<typename _Tp> 00347 class shared_ptr; 00348 00349 template<typename _Tp> 00350 class weak_ptr; 00351 00352 template<typename _Tp> 00353 struct owner_less; 00354 00355 template<typename _Tp> 00356 class enable_shared_from_this; 00357 00358 template<_Lock_policy _Lp = __default_lock_policy> 00359 class __weak_count; 00360 00361 template<_Lock_policy _Lp = __default_lock_policy> 00362 class __shared_count; 00363 00364 00365 // Counted ptr with no deleter or allocator support 00366 template<typename _Ptr, _Lock_policy _Lp> 00367 class _Sp_counted_ptr final : public _Sp_counted_base<_Lp> 00368 { 00369 public: 00370 explicit 00371 _Sp_counted_ptr(_Ptr __p) noexcept 00372 : _M_ptr(__p) { } 00373 00374 virtual void 00375 _M_dispose() noexcept 00376 { delete _M_ptr; } 00377 00378 virtual void 00379 _M_destroy() noexcept 00380 { delete this; } 00381 00382 virtual void* 00383 _M_get_deleter(const std::type_info&) noexcept 00384 { return nullptr; } 00385 00386 _Sp_counted_ptr(const _Sp_counted_ptr&) = delete; 00387 _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete; 00388 00389 private: 00390 _Ptr _M_ptr; 00391 }; 00392 00393 template<> 00394 inline void 00395 _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { } 00396 00397 template<> 00398 inline void 00399 _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { } 00400 00401 template<> 00402 inline void 00403 _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { } 00404 00405 template<int _Nm, typename _Tp, 00406 bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)> 00407 struct _Sp_ebo_helper; 00408 00409 /// Specialization using EBO. 00410 template<int _Nm, typename _Tp> 00411 struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp 00412 { 00413 explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { } 00414 explicit _Sp_ebo_helper(_Tp&& __tp) : _Tp(std::move(__tp)) { } 00415 00416 static _Tp& 00417 _S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); } 00418 }; 00419 00420 /// Specialization not using EBO. 00421 template<int _Nm, typename _Tp> 00422 struct _Sp_ebo_helper<_Nm, _Tp, false> 00423 { 00424 explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { } 00425 explicit _Sp_ebo_helper(_Tp&& __tp) : _M_tp(std::move(__tp)) { } 00426 00427 static _Tp& 00428 _S_get(_Sp_ebo_helper& __eboh) 00429 { return __eboh._M_tp; } 00430 00431 private: 00432 _Tp _M_tp; 00433 }; 00434 00435 // Support for custom deleter and/or allocator 00436 template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp> 00437 class _Sp_counted_deleter final : public _Sp_counted_base<_Lp> 00438 { 00439 class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc> 00440 { 00441 typedef _Sp_ebo_helper<0, _Deleter> _Del_base; 00442 typedef _Sp_ebo_helper<1, _Alloc> _Alloc_base; 00443 00444 public: 00445 _Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept 00446 : _M_ptr(__p), _Del_base(std::move(__d)), _Alloc_base(__a) 00447 { } 00448 00449 _Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); } 00450 _Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); } 00451 00452 _Ptr _M_ptr; 00453 }; 00454 00455 public: 00456 using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_deleter>; 00457 00458 // __d(__p) must not throw. 00459 _Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept 00460 : _M_impl(__p, std::move(__d), _Alloc()) { } 00461 00462 // __d(__p) must not throw. 00463 _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept 00464 : _M_impl(__p, std::move(__d), __a) { } 00465 00466 ~_Sp_counted_deleter() noexcept { } 00467 00468 virtual void 00469 _M_dispose() noexcept 00470 { _M_impl._M_del()(_M_impl._M_ptr); } 00471 00472 virtual void 00473 _M_destroy() noexcept 00474 { 00475 __allocator_type __a(_M_impl._M_alloc()); 00476 __allocated_ptr<__allocator_type> __guard_ptr{ __a, this }; 00477 this->~_Sp_counted_deleter(); 00478 } 00479 00480 virtual void* 00481 _M_get_deleter(const std::type_info& __ti) noexcept 00482 { 00483 #if __cpp_rtti 00484 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00485 // 2400. shared_ptr's get_deleter() should use addressof() 00486 return __ti == typeid(_Deleter) 00487 ? std::__addressof(_M_impl._M_del()) 00488 : nullptr; 00489 #else 00490 return nullptr; 00491 #endif 00492 } 00493 00494 private: 00495 _Impl _M_impl; 00496 }; 00497 00498 // helpers for make_shared / allocate_shared 00499 00500 struct _Sp_make_shared_tag { }; 00501 00502 template<typename _Tp, typename _Alloc, _Lock_policy _Lp> 00503 class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp> 00504 { 00505 class _Impl : _Sp_ebo_helper<0, _Alloc> 00506 { 00507 typedef _Sp_ebo_helper<0, _Alloc> _A_base; 00508 00509 public: 00510 explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { } 00511 00512 _Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); } 00513 00514 __gnu_cxx::__aligned_buffer<_Tp> _M_storage; 00515 }; 00516 00517 public: 00518 using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>; 00519 00520 template<typename... _Args> 00521 _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args) 00522 : _M_impl(__a) 00523 { 00524 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00525 // 2070. allocate_shared should use allocator_traits<A>::construct 00526 allocator_traits<_Alloc>::construct(__a, _M_ptr(), 00527 std::forward<_Args>(__args)...); // might throw 00528 } 00529 00530 ~_Sp_counted_ptr_inplace() noexcept { } 00531 00532 virtual void 00533 _M_dispose() noexcept 00534 { 00535 allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr()); 00536 } 00537 00538 // Override because the allocator needs to know the dynamic type 00539 virtual void 00540 _M_destroy() noexcept 00541 { 00542 __allocator_type __a(_M_impl._M_alloc()); 00543 __allocated_ptr<__allocator_type> __guard_ptr{ __a, this }; 00544 this->~_Sp_counted_ptr_inplace(); 00545 } 00546 00547 // Sneaky trick so __shared_ptr can get the managed pointer 00548 virtual void* 00549 _M_get_deleter(const std::type_info& __ti) noexcept 00550 { 00551 #if __cpp_rtti 00552 if (__ti == typeid(_Sp_make_shared_tag)) 00553 return const_cast<typename remove_cv<_Tp>::type*>(_M_ptr()); 00554 #endif 00555 return nullptr; 00556 } 00557 00558 private: 00559 _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); } 00560 00561 _Impl _M_impl; 00562 }; 00563 00564 // The default deleter for shared_ptr<T[]> and shared_ptr<T[N]>. 00565 struct __sp_array_delete 00566 { 00567 template<typename _Yp> 00568 void operator()(_Yp* __p) const { delete[] __p; } 00569 }; 00570 00571 template<_Lock_policy _Lp> 00572 class __shared_count 00573 { 00574 public: 00575 constexpr __shared_count() noexcept : _M_pi(0) 00576 { } 00577 00578 template<typename _Ptr> 00579 explicit 00580 __shared_count(_Ptr __p) : _M_pi(0) 00581 { 00582 __try 00583 { 00584 _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p); 00585 } 00586 __catch(...) 00587 { 00588 delete __p; 00589 __throw_exception_again; 00590 } 00591 } 00592 00593 template<typename _Ptr> 00594 __shared_count(_Ptr __p, /* is_array = */ false_type) 00595 : __shared_count(__p) 00596 { } 00597 00598 template<typename _Ptr> 00599 __shared_count(_Ptr __p, /* is_array = */ true_type) 00600 : __shared_count(__p, __sp_array_delete{}, allocator<void>()) 00601 { } 00602 00603 template<typename _Ptr, typename _Deleter> 00604 __shared_count(_Ptr __p, _Deleter __d) 00605 : __shared_count(__p, std::move(__d), allocator<void>()) 00606 { } 00607 00608 template<typename _Ptr, typename _Deleter, typename _Alloc> 00609 __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0) 00610 { 00611 typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type; 00612 __try 00613 { 00614 typename _Sp_cd_type::__allocator_type __a2(__a); 00615 auto __guard = std::__allocate_guarded(__a2); 00616 _Sp_cd_type* __mem = __guard.get(); 00617 ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a)); 00618 _M_pi = __mem; 00619 __guard = nullptr; 00620 } 00621 __catch(...) 00622 { 00623 __d(__p); // Call _Deleter on __p. 00624 __throw_exception_again; 00625 } 00626 } 00627 00628 template<typename _Tp, typename _Alloc, typename... _Args> 00629 __shared_count(_Sp_make_shared_tag, _Tp*, const _Alloc& __a, 00630 _Args&&... __args) 00631 : _M_pi(0) 00632 { 00633 typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type; 00634 typename _Sp_cp_type::__allocator_type __a2(__a); 00635 auto __guard = std::__allocate_guarded(__a2); 00636 _Sp_cp_type* __mem = __guard.get(); 00637 ::new (__mem) _Sp_cp_type(std::move(__a), 00638 std::forward<_Args>(__args)...); 00639 _M_pi = __mem; 00640 __guard = nullptr; 00641 } 00642 00643 #if _GLIBCXX_USE_DEPRECATED 00644 // Special case for auto_ptr<_Tp> to provide the strong guarantee. 00645 template<typename _Tp> 00646 explicit 00647 __shared_count(std::auto_ptr<_Tp>&& __r); 00648 #endif 00649 00650 // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee. 00651 template<typename _Tp, typename _Del> 00652 explicit 00653 __shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0) 00654 { 00655 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00656 // 2415. Inconsistency between unique_ptr and shared_ptr 00657 if (__r.get() == nullptr) 00658 return; 00659 00660 using _Ptr = typename unique_ptr<_Tp, _Del>::pointer; 00661 using _Del2 = typename conditional<is_reference<_Del>::value, 00662 reference_wrapper<typename remove_reference<_Del>::type>, 00663 _Del>::type; 00664 using _Sp_cd_type 00665 = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>; 00666 using _Alloc = allocator<_Sp_cd_type>; 00667 using _Alloc_traits = allocator_traits<_Alloc>; 00668 _Alloc __a; 00669 _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1); 00670 _Alloc_traits::construct(__a, __mem, __r.release(), 00671 __r.get_deleter()); // non-throwing 00672 _M_pi = __mem; 00673 } 00674 00675 // Throw bad_weak_ptr when __r._M_get_use_count() == 0. 00676 explicit __shared_count(const __weak_count<_Lp>& __r); 00677 00678 // Does not throw if __r._M_get_use_count() == 0, caller must check. 00679 explicit __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t); 00680 00681 ~__shared_count() noexcept 00682 { 00683 if (_M_pi != nullptr) 00684 _M_pi->_M_release(); 00685 } 00686 00687 __shared_count(const __shared_count& __r) noexcept 00688 : _M_pi(__r._M_pi) 00689 { 00690 if (_M_pi != 0) 00691 _M_pi->_M_add_ref_copy(); 00692 } 00693 00694 __shared_count& 00695 operator=(const __shared_count& __r) noexcept 00696 { 00697 _Sp_counted_base<_Lp>* __tmp = __r._M_pi; 00698 if (__tmp != _M_pi) 00699 { 00700 if (__tmp != 0) 00701 __tmp->_M_add_ref_copy(); 00702 if (_M_pi != 0) 00703 _M_pi->_M_release(); 00704 _M_pi = __tmp; 00705 } 00706 return *this; 00707 } 00708 00709 void 00710 _M_swap(__shared_count& __r) noexcept 00711 { 00712 _Sp_counted_base<_Lp>* __tmp = __r._M_pi; 00713 __r._M_pi = _M_pi; 00714 _M_pi = __tmp; 00715 } 00716 00717 long 00718 _M_get_use_count() const noexcept 00719 { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; } 00720 00721 bool 00722 _M_unique() const noexcept 00723 { return this->_M_get_use_count() == 1; } 00724 00725 void* 00726 _M_get_deleter(const std::type_info& __ti) const noexcept 00727 { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; } 00728 00729 bool 00730 _M_less(const __shared_count& __rhs) const noexcept 00731 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } 00732 00733 bool 00734 _M_less(const __weak_count<_Lp>& __rhs) const noexcept 00735 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } 00736 00737 // Friend function injected into enclosing namespace and found by ADL 00738 friend inline bool 00739 operator==(const __shared_count& __a, const __shared_count& __b) noexcept 00740 { return __a._M_pi == __b._M_pi; } 00741 00742 private: 00743 friend class __weak_count<_Lp>; 00744 00745 _Sp_counted_base<_Lp>* _M_pi; 00746 }; 00747 00748 00749 template<_Lock_policy _Lp> 00750 class __weak_count 00751 { 00752 public: 00753 constexpr __weak_count() noexcept : _M_pi(nullptr) 00754 { } 00755 00756 __weak_count(const __shared_count<_Lp>& __r) noexcept 00757 : _M_pi(__r._M_pi) 00758 { 00759 if (_M_pi != nullptr) 00760 _M_pi->_M_weak_add_ref(); 00761 } 00762 00763 __weak_count(const __weak_count& __r) noexcept 00764 : _M_pi(__r._M_pi) 00765 { 00766 if (_M_pi != nullptr) 00767 _M_pi->_M_weak_add_ref(); 00768 } 00769 00770 __weak_count(__weak_count&& __r) noexcept 00771 : _M_pi(__r._M_pi) 00772 { __r._M_pi = nullptr; } 00773 00774 ~__weak_count() noexcept 00775 { 00776 if (_M_pi != nullptr) 00777 _M_pi->_M_weak_release(); 00778 } 00779 00780 __weak_count& 00781 operator=(const __shared_count<_Lp>& __r) noexcept 00782 { 00783 _Sp_counted_base<_Lp>* __tmp = __r._M_pi; 00784 if (__tmp != nullptr) 00785 __tmp->_M_weak_add_ref(); 00786 if (_M_pi != nullptr) 00787 _M_pi->_M_weak_release(); 00788 _M_pi = __tmp; 00789 return *this; 00790 } 00791 00792 __weak_count& 00793 operator=(const __weak_count& __r) noexcept 00794 { 00795 _Sp_counted_base<_Lp>* __tmp = __r._M_pi; 00796 if (__tmp != nullptr) 00797 __tmp->_M_weak_add_ref(); 00798 if (_M_pi != nullptr) 00799 _M_pi->_M_weak_release(); 00800 _M_pi = __tmp; 00801 return *this; 00802 } 00803 00804 __weak_count& 00805 operator=(__weak_count&& __r) noexcept 00806 { 00807 if (_M_pi != nullptr) 00808 _M_pi->_M_weak_release(); 00809 _M_pi = __r._M_pi; 00810 __r._M_pi = nullptr; 00811 return *this; 00812 } 00813 00814 void 00815 _M_swap(__weak_count& __r) noexcept 00816 { 00817 _Sp_counted_base<_Lp>* __tmp = __r._M_pi; 00818 __r._M_pi = _M_pi; 00819 _M_pi = __tmp; 00820 } 00821 00822 long 00823 _M_get_use_count() const noexcept 00824 { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; } 00825 00826 bool 00827 _M_less(const __weak_count& __rhs) const noexcept 00828 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } 00829 00830 bool 00831 _M_less(const __shared_count<_Lp>& __rhs) const noexcept 00832 { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } 00833 00834 // Friend function injected into enclosing namespace and found by ADL 00835 friend inline bool 00836 operator==(const __weak_count& __a, const __weak_count& __b) noexcept 00837 { return __a._M_pi == __b._M_pi; } 00838 00839 private: 00840 friend class __shared_count<_Lp>; 00841 00842 _Sp_counted_base<_Lp>* _M_pi; 00843 }; 00844 00845 // Now that __weak_count is defined we can define this constructor: 00846 template<_Lock_policy _Lp> 00847 inline 00848 __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r) 00849 : _M_pi(__r._M_pi) 00850 { 00851 if (_M_pi != nullptr) 00852 _M_pi->_M_add_ref_lock(); 00853 else 00854 __throw_bad_weak_ptr(); 00855 } 00856 00857 // Now that __weak_count is defined we can define this constructor: 00858 template<_Lock_policy _Lp> 00859 inline 00860 __shared_count<_Lp>:: 00861 __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t) 00862 : _M_pi(__r._M_pi) 00863 { 00864 if (_M_pi != nullptr) 00865 if (!_M_pi->_M_add_ref_lock_nothrow()) 00866 _M_pi = nullptr; 00867 } 00868 00869 #define __cpp_lib_shared_ptr_arrays 201603 00870 00871 // Helper traits for shared_ptr of array: 00872 00873 // A pointer type Y* is said to be compatible with a pointer type T* when 00874 // either Y* is convertible to T* or Y is U[N] and T is U cv []. 00875 template<typename _Yp_ptr, typename _Tp_ptr> 00876 struct __sp_compatible_with 00877 : false_type 00878 { }; 00879 00880 template<typename _Yp, typename _Tp> 00881 struct __sp_compatible_with<_Yp*, _Tp*> 00882 : is_convertible<_Yp*, _Tp*>::type 00883 { }; 00884 00885 template<typename _Up, size_t _Nm> 00886 struct __sp_compatible_with<_Up(*)[_Nm], _Up(*)[]> 00887 : true_type 00888 { }; 00889 00890 template<typename _Up, size_t _Nm> 00891 struct __sp_compatible_with<_Up(*)[_Nm], const _Up(*)[]> 00892 : true_type 00893 { }; 00894 00895 template<typename _Up, size_t _Nm> 00896 struct __sp_compatible_with<_Up(*)[_Nm], volatile _Up(*)[]> 00897 : true_type 00898 { }; 00899 00900 template<typename _Up, size_t _Nm> 00901 struct __sp_compatible_with<_Up(*)[_Nm], const volatile _Up(*)[]> 00902 : true_type 00903 { }; 00904 00905 // Test conversion from Y(*)[N] to U(*)[N] without forming invalid type Y[N]. 00906 template<typename _Up, size_t _Nm, typename _Yp, typename = void> 00907 struct __sp_is_constructible_arrN 00908 : false_type 00909 { }; 00910 00911 template<typename _Up, size_t _Nm, typename _Yp> 00912 struct __sp_is_constructible_arrN<_Up, _Nm, _Yp, __void_t<_Yp[_Nm]>> 00913 : is_convertible<_Yp(*)[_Nm], _Up(*)[_Nm]>::type 00914 { }; 00915 00916 // Test conversion from Y(*)[] to U(*)[] without forming invalid type Y[]. 00917 template<typename _Up, typename _Yp, typename = void> 00918 struct __sp_is_constructible_arr 00919 : false_type 00920 { }; 00921 00922 template<typename _Up, typename _Yp> 00923 struct __sp_is_constructible_arr<_Up, _Yp, __void_t<_Yp[]>> 00924 : is_convertible<_Yp(*)[], _Up(*)[]>::type 00925 { }; 00926 00927 // Trait to check if shared_ptr<T> can be constructed from Y*. 00928 template<typename _Tp, typename _Yp> 00929 struct __sp_is_constructible; 00930 00931 // When T is U[N], Y(*)[N] shall be convertible to T*; 00932 template<typename _Up, size_t _Nm, typename _Yp> 00933 struct __sp_is_constructible<_Up[_Nm], _Yp> 00934 : __sp_is_constructible_arrN<_Up, _Nm, _Yp>::type 00935 { }; 00936 00937 // when T is U[], Y(*)[] shall be convertible to T*; 00938 template<typename _Up, typename _Yp> 00939 struct __sp_is_constructible<_Up[], _Yp> 00940 : __sp_is_constructible_arr<_Up, _Yp>::type 00941 { }; 00942 00943 // otherwise, Y* shall be convertible to T*. 00944 template<typename _Tp, typename _Yp> 00945 struct __sp_is_constructible 00946 : is_convertible<_Yp*, _Tp*>::type 00947 { }; 00948 00949 00950 // Define operator* and operator-> for shared_ptr<T>. 00951 template<typename _Tp, _Lock_policy _Lp, 00952 bool = is_array<_Tp>::value, bool = is_void<_Tp>::value> 00953 class __shared_ptr_access 00954 { 00955 public: 00956 using element_type = _Tp; 00957 00958 element_type& 00959 operator*() const noexcept 00960 { 00961 __glibcxx_assert(_M_get() != nullptr); 00962 return *_M_get(); 00963 } 00964 00965 element_type* 00966 operator->() const noexcept 00967 { 00968 _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr); 00969 return _M_get(); 00970 } 00971 00972 private: 00973 element_type* 00974 _M_get() const noexcept 00975 { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); } 00976 }; 00977 00978 // Define operator-> for shared_ptr<cv void>. 00979 template<typename _Tp, _Lock_policy _Lp> 00980 class __shared_ptr_access<_Tp, _Lp, false, true> 00981 { 00982 public: 00983 using element_type = _Tp; 00984 00985 element_type* 00986 operator->() const noexcept 00987 { 00988 auto __ptr = static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); 00989 _GLIBCXX_DEBUG_PEDASSERT(__ptr != nullptr); 00990 return __ptr; 00991 } 00992 }; 00993 00994 // Define operator[] for shared_ptr<T[]> and shared_ptr<T[N]>. 00995 template<typename _Tp, _Lock_policy _Lp> 00996 class __shared_ptr_access<_Tp, _Lp, true, false> 00997 { 00998 public: 00999 using element_type = typename remove_extent<_Tp>::type; 01000 01001 #if __cplusplus <= 201402L 01002 [[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17")]] 01003 element_type& 01004 operator*() const noexcept 01005 { 01006 __glibcxx_assert(_M_get() != nullptr); 01007 return *_M_get(); 01008 } 01009 01010 [[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17")]] 01011 element_type* 01012 operator->() const noexcept 01013 { 01014 _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr); 01015 return _M_get(); 01016 } 01017 #endif 01018 01019 element_type& 01020 operator[](ptrdiff_t __i) const 01021 { 01022 __glibcxx_assert(_M_get() != nullptr); 01023 __glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value); 01024 return _M_get()[__i]; 01025 } 01026 01027 private: 01028 element_type* 01029 _M_get() const noexcept 01030 { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); } 01031 }; 01032 01033 template<typename _Tp, _Lock_policy _Lp> 01034 class __shared_ptr 01035 : public __shared_ptr_access<_Tp, _Lp> 01036 { 01037 public: 01038 using element_type = typename remove_extent<_Tp>::type; 01039 01040 private: 01041 // Constraint for taking ownership of a pointer of type _Yp*: 01042 template<typename _Yp> 01043 using _SafeConv 01044 = typename enable_if<__sp_is_constructible<_Tp, _Yp>::value>::type; 01045 01046 // Constraint for construction from shared_ptr and weak_ptr: 01047 template<typename _Yp, typename _Res = void> 01048 using _Compatible = typename 01049 enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type; 01050 01051 // Constraint for assignment from shared_ptr and weak_ptr: 01052 template<typename _Yp> 01053 using _Assignable = _Compatible<_Yp, __shared_ptr&>; 01054 01055 // Constraint for construction from unique_ptr: 01056 template<typename _Yp, typename _Del, typename _Res = void, 01057 typename _Ptr = typename unique_ptr<_Yp, _Del>::pointer> 01058 using _UniqCompatible = typename enable_if<__and_< 01059 __sp_compatible_with<_Yp*, _Tp*>, is_convertible<_Ptr, element_type*> 01060 >::value, _Res>::type; 01061 01062 // Constraint for assignment from unique_ptr: 01063 template<typename _Yp, typename _Del> 01064 using _UniqAssignable = _UniqCompatible<_Yp, _Del, __shared_ptr&>; 01065 01066 public: 01067 01068 #if __cplusplus > 201402L 01069 using weak_type = __weak_ptr<_Tp, _Lp>; 01070 #endif 01071 01072 constexpr __shared_ptr() noexcept 01073 : _M_ptr(0), _M_refcount() 01074 { } 01075 01076 template<typename _Yp, typename = _SafeConv<_Yp>> 01077 explicit 01078 __shared_ptr(_Yp* __p) 01079 : _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type()) 01080 { 01081 static_assert( !is_void<_Yp>::value, "incomplete type" ); 01082 static_assert( sizeof(_Yp) > 0, "incomplete type" ); 01083 _M_enable_shared_from_this_with(__p); 01084 } 01085 01086 template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>> 01087 __shared_ptr(_Yp* __p, _Deleter __d) 01088 : _M_ptr(__p), _M_refcount(__p, std::move(__d)) 01089 { 01090 static_assert(__is_invocable<_Deleter&, _Yp*&>::value, 01091 "deleter expression d(p) is well-formed"); 01092 _M_enable_shared_from_this_with(__p); 01093 } 01094 01095 template<typename _Yp, typename _Deleter, typename _Alloc, 01096 typename = _SafeConv<_Yp>> 01097 __shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a) 01098 : _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a)) 01099 { 01100 static_assert(__is_invocable<_Deleter&, _Yp*&>::value, 01101 "deleter expression d(p) is well-formed"); 01102 _M_enable_shared_from_this_with(__p); 01103 } 01104 01105 template<typename _Deleter> 01106 __shared_ptr(nullptr_t __p, _Deleter __d) 01107 : _M_ptr(0), _M_refcount(__p, std::move(__d)) 01108 { } 01109 01110 template<typename _Deleter, typename _Alloc> 01111 __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a) 01112 : _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a)) 01113 { } 01114 01115 template<typename _Yp> 01116 __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r, 01117 element_type* __p) noexcept 01118 : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws 01119 { } 01120 01121 __shared_ptr(const __shared_ptr&) noexcept = default; 01122 __shared_ptr& operator=(const __shared_ptr&) noexcept = default; 01123 ~__shared_ptr() = default; 01124 01125 template<typename _Yp, typename = _Compatible<_Yp>> 01126 __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept 01127 : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) 01128 { } 01129 01130 __shared_ptr(__shared_ptr&& __r) noexcept 01131 : _M_ptr(__r._M_ptr), _M_refcount() 01132 { 01133 _M_refcount._M_swap(__r._M_refcount); 01134 __r._M_ptr = 0; 01135 } 01136 01137 template<typename _Yp, typename = _Compatible<_Yp>> 01138 __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r) noexcept 01139 : _M_ptr(__r._M_ptr), _M_refcount() 01140 { 01141 _M_refcount._M_swap(__r._M_refcount); 01142 __r._M_ptr = 0; 01143 } 01144 01145 template<typename _Yp, typename = _Compatible<_Yp>> 01146 explicit __shared_ptr(const __weak_ptr<_Yp, _Lp>& __r) 01147 : _M_refcount(__r._M_refcount) // may throw 01148 { 01149 // It is now safe to copy __r._M_ptr, as 01150 // _M_refcount(__r._M_refcount) did not throw. 01151 _M_ptr = __r._M_ptr; 01152 } 01153 01154 // If an exception is thrown this constructor has no effect. 01155 template<typename _Yp, typename _Del, 01156 typename = _UniqCompatible<_Yp, _Del>> 01157 __shared_ptr(unique_ptr<_Yp, _Del>&& __r) 01158 : _M_ptr(__r.get()), _M_refcount() 01159 { 01160 auto __raw = _S_raw_ptr(__r.get()); 01161 _M_refcount = __shared_count<_Lp>(std::move(__r)); 01162 _M_enable_shared_from_this_with(__raw); 01163 } 01164 01165 #if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED 01166 protected: 01167 // If an exception is thrown this constructor has no effect. 01168 template<typename _Tp1, typename _Del, 01169 typename enable_if<__and_< 01170 __not_<is_array<_Tp>>, is_array<_Tp1>, 01171 is_convertible<typename unique_ptr<_Tp1, _Del>::pointer, _Tp*> 01172 >::value, bool>::type = true> 01173 __shared_ptr(unique_ptr<_Tp1, _Del>&& __r, __sp_array_delete) 01174 : _M_ptr(__r.get()), _M_refcount() 01175 { 01176 auto __raw = _S_raw_ptr(__r.get()); 01177 _M_refcount = __shared_count<_Lp>(std::move(__r)); 01178 _M_enable_shared_from_this_with(__raw); 01179 } 01180 public: 01181 #endif 01182 01183 #if _GLIBCXX_USE_DEPRECATED 01184 // Postcondition: use_count() == 1 and __r.get() == 0 01185 template<typename _Yp, typename = _Compatible<_Yp>> 01186 __shared_ptr(auto_ptr<_Yp>&& __r); 01187 #endif 01188 01189 constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { } 01190 01191 template<typename _Yp> 01192 _Assignable<_Yp> 01193 operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept 01194 { 01195 _M_ptr = __r._M_ptr; 01196 _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw 01197 return *this; 01198 } 01199 01200 #if _GLIBCXX_USE_DEPRECATED 01201 template<typename _Yp> 01202 _Assignable<_Yp> 01203 operator=(auto_ptr<_Yp>&& __r) 01204 { 01205 __shared_ptr(std::move(__r)).swap(*this); 01206 return *this; 01207 } 01208 #endif 01209 01210 __shared_ptr& 01211 operator=(__shared_ptr&& __r) noexcept 01212 { 01213 __shared_ptr(std::move(__r)).swap(*this); 01214 return *this; 01215 } 01216 01217 template<class _Yp> 01218 _Assignable<_Yp> 01219 operator=(__shared_ptr<_Yp, _Lp>&& __r) noexcept 01220 { 01221 __shared_ptr(std::move(__r)).swap(*this); 01222 return *this; 01223 } 01224 01225 template<typename _Yp, typename _Del> 01226 _UniqAssignable<_Yp, _Del> 01227 operator=(unique_ptr<_Yp, _Del>&& __r) 01228 { 01229 __shared_ptr(std::move(__r)).swap(*this); 01230 return *this; 01231 } 01232 01233 void 01234 reset() noexcept 01235 { __shared_ptr().swap(*this); } 01236 01237 template<typename _Yp> 01238 _SafeConv<_Yp> 01239 reset(_Yp* __p) // _Yp must be complete. 01240 { 01241 // Catch self-reset errors. 01242 __glibcxx_assert(__p == 0 || __p != _M_ptr); 01243 __shared_ptr(__p).swap(*this); 01244 } 01245 01246 template<typename _Yp, typename _Deleter> 01247 _SafeConv<_Yp> 01248 reset(_Yp* __p, _Deleter __d) 01249 { __shared_ptr(__p, std::move(__d)).swap(*this); } 01250 01251 template<typename _Yp, typename _Deleter, typename _Alloc> 01252 _SafeConv<_Yp> 01253 reset(_Yp* __p, _Deleter __d, _Alloc __a) 01254 { __shared_ptr(__p, std::move(__d), std::move(__a)).swap(*this); } 01255 01256 element_type* 01257 get() const noexcept 01258 { return _M_ptr; } 01259 01260 explicit operator bool() const // never throws 01261 { return _M_ptr == 0 ? false : true; } 01262 01263 bool 01264 unique() const noexcept 01265 { return _M_refcount._M_unique(); } 01266 01267 long 01268 use_count() const noexcept 01269 { return _M_refcount._M_get_use_count(); } 01270 01271 void 01272 swap(__shared_ptr<_Tp, _Lp>& __other) noexcept 01273 { 01274 std::swap(_M_ptr, __other._M_ptr); 01275 _M_refcount._M_swap(__other._M_refcount); 01276 } 01277 01278 template<typename _Tp1> 01279 bool 01280 owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const noexcept 01281 { return _M_refcount._M_less(__rhs._M_refcount); } 01282 01283 template<typename _Tp1> 01284 bool 01285 owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const noexcept 01286 { return _M_refcount._M_less(__rhs._M_refcount); } 01287 01288 #if __cpp_rtti 01289 protected: 01290 // This constructor is non-standard, it is used by allocate_shared. 01291 template<typename _Alloc, typename... _Args> 01292 __shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a, 01293 _Args&&... __args) 01294 : _M_ptr(), _M_refcount(__tag, (_Tp*)0, __a, 01295 std::forward<_Args>(__args)...) 01296 { 01297 // _M_ptr needs to point to the newly constructed object. 01298 // This relies on _Sp_counted_ptr_inplace::_M_get_deleter. 01299 void* __p = _M_refcount._M_get_deleter(typeid(__tag)); 01300 _M_ptr = static_cast<_Tp*>(__p); 01301 _M_enable_shared_from_this_with(_M_ptr); 01302 } 01303 #else 01304 template<typename _Alloc> 01305 struct _Deleter 01306 { 01307 void operator()(typename _Alloc::value_type* __ptr) 01308 { 01309 __allocated_ptr<_Alloc> __guard{ _M_alloc, __ptr }; 01310 allocator_traits<_Alloc>::destroy(_M_alloc, __guard.get()); 01311 } 01312 _Alloc _M_alloc; 01313 }; 01314 01315 template<typename _Alloc, typename... _Args> 01316 __shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a, 01317 _Args&&... __args) 01318 : _M_ptr(), _M_refcount() 01319 { 01320 typedef typename allocator_traits<_Alloc>::template 01321 rebind_traits<typename std::remove_cv<_Tp>::type> __traits; 01322 _Deleter<typename __traits::allocator_type> __del = { __a }; 01323 auto __guard = std::__allocate_guarded(__del._M_alloc); 01324 auto __ptr = __guard.get(); 01325 // _GLIBCXX_RESOLVE_LIB_DEFECTS 01326 // 2070. allocate_shared should use allocator_traits<A>::construct 01327 __traits::construct(__del._M_alloc, __ptr, 01328 std::forward<_Args>(__args)...); 01329 __guard = nullptr; 01330 __shared_count<_Lp> __count(__ptr, __del, __del._M_alloc); 01331 _M_refcount._M_swap(__count); 01332 _M_ptr = __ptr; 01333 _M_enable_shared_from_this_with(_M_ptr); 01334 } 01335 #endif 01336 01337 template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc, 01338 typename... _Args> 01339 friend __shared_ptr<_Tp1, _Lp1> 01340 __allocate_shared(const _Alloc& __a, _Args&&... __args); 01341 01342 // This constructor is used by __weak_ptr::lock() and 01343 // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t). 01344 __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t) 01345 : _M_refcount(__r._M_refcount, std::nothrow) 01346 { 01347 _M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr; 01348 } 01349 01350 friend class __weak_ptr<_Tp, _Lp>; 01351 01352 private: 01353 01354 template<typename _Yp> 01355 using __esft_base_t = decltype(__enable_shared_from_this_base( 01356 std::declval<const __shared_count<_Lp>&>(), 01357 std::declval<_Yp*>())); 01358 01359 // Detect an accessible and unambiguous enable_shared_from_this base. 01360 template<typename _Yp, typename = void> 01361 struct __has_esft_base 01362 : false_type { }; 01363 01364 template<typename _Yp> 01365 struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>> 01366 : __not_<is_array<_Tp>> { }; // No enable shared_from_this for arrays 01367 01368 template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type> 01369 typename enable_if<__has_esft_base<_Yp2>::value>::type 01370 _M_enable_shared_from_this_with(_Yp* __p) noexcept 01371 { 01372 if (auto __base = __enable_shared_from_this_base(_M_refcount, __p)) 01373 __base->_M_weak_assign(const_cast<_Yp2*>(__p), _M_refcount); 01374 } 01375 01376 template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type> 01377 typename enable_if<!__has_esft_base<_Yp2>::value>::type 01378 _M_enable_shared_from_this_with(_Yp*) noexcept 01379 { } 01380 01381 void* 01382 _M_get_deleter(const std::type_info& __ti) const noexcept 01383 { return _M_refcount._M_get_deleter(__ti); } 01384 01385 template<typename _Tp1> 01386 static _Tp1* 01387 _S_raw_ptr(_Tp1* __ptr) 01388 { return __ptr; } 01389 01390 template<typename _Tp1> 01391 static auto 01392 _S_raw_ptr(_Tp1 __ptr) -> decltype(std::__addressof(*__ptr)) 01393 { return std::__addressof(*__ptr); } 01394 01395 template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; 01396 template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; 01397 01398 template<typename _Del, typename _Tp1, _Lock_policy _Lp1> 01399 friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&) noexcept; 01400 01401 element_type* _M_ptr; // Contained pointer. 01402 __shared_count<_Lp> _M_refcount; // Reference counter. 01403 }; 01404 01405 01406 // 20.7.2.2.7 shared_ptr comparisons 01407 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> 01408 inline bool 01409 operator==(const __shared_ptr<_Tp1, _Lp>& __a, 01410 const __shared_ptr<_Tp2, _Lp>& __b) noexcept 01411 { return __a.get() == __b.get(); } 01412 01413 template<typename _Tp, _Lock_policy _Lp> 01414 inline bool 01415 operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept 01416 { return !__a; } 01417 01418 template<typename _Tp, _Lock_policy _Lp> 01419 inline bool 01420 operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept 01421 { return !__a; } 01422 01423 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> 01424 inline bool 01425 operator!=(const __shared_ptr<_Tp1, _Lp>& __a, 01426 const __shared_ptr<_Tp2, _Lp>& __b) noexcept 01427 { return __a.get() != __b.get(); } 01428 01429 template<typename _Tp, _Lock_policy _Lp> 01430 inline bool 01431 operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept 01432 { return (bool)__a; } 01433 01434 template<typename _Tp, _Lock_policy _Lp> 01435 inline bool 01436 operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept 01437 { return (bool)__a; } 01438 01439 template<typename _Tp, typename _Up, _Lock_policy _Lp> 01440 inline bool 01441 operator<(const __shared_ptr<_Tp, _Lp>& __a, 01442 const __shared_ptr<_Up, _Lp>& __b) noexcept 01443 { 01444 using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type; 01445 using _Up_elt = typename __shared_ptr<_Up, _Lp>::element_type; 01446 using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type; 01447 return less<_Vp>()(__a.get(), __b.get()); 01448 } 01449 01450 template<typename _Tp, _Lock_policy _Lp> 01451 inline bool 01452 operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept 01453 { 01454 using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type; 01455 return less<_Tp_elt*>()(__a.get(), nullptr); 01456 } 01457 01458 template<typename _Tp, _Lock_policy _Lp> 01459 inline bool 01460 operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept 01461 { 01462 using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type; 01463 return less<_Tp_elt*>()(nullptr, __a.get()); 01464 } 01465 01466 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> 01467 inline bool 01468 operator<=(const __shared_ptr<_Tp1, _Lp>& __a, 01469 const __shared_ptr<_Tp2, _Lp>& __b) noexcept 01470 { return !(__b < __a); } 01471 01472 template<typename _Tp, _Lock_policy _Lp> 01473 inline bool 01474 operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept 01475 { return !(nullptr < __a); } 01476 01477 template<typename _Tp, _Lock_policy _Lp> 01478 inline bool 01479 operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept 01480 { return !(__a < nullptr); } 01481 01482 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> 01483 inline bool 01484 operator>(const __shared_ptr<_Tp1, _Lp>& __a, 01485 const __shared_ptr<_Tp2, _Lp>& __b) noexcept 01486 { return (__b < __a); } 01487 01488 template<typename _Tp, _Lock_policy _Lp> 01489 inline bool 01490 operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept 01491 { return nullptr < __a; } 01492 01493 template<typename _Tp, _Lock_policy _Lp> 01494 inline bool 01495 operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept 01496 { return __a < nullptr; } 01497 01498 template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> 01499 inline bool 01500 operator>=(const __shared_ptr<_Tp1, _Lp>& __a, 01501 const __shared_ptr<_Tp2, _Lp>& __b) noexcept 01502 { return !(__a < __b); } 01503 01504 template<typename _Tp, _Lock_policy _Lp> 01505 inline bool 01506 operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept 01507 { return !(__a < nullptr); } 01508 01509 template<typename _Tp, _Lock_policy _Lp> 01510 inline bool 01511 operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept 01512 { return !(nullptr < __a); } 01513 01514 template<typename _Sp> 01515 struct _Sp_less : public binary_function<_Sp, _Sp, bool> 01516 { 01517 bool 01518 operator()(const _Sp& __lhs, const _Sp& __rhs) const noexcept 01519 { 01520 typedef typename _Sp::element_type element_type; 01521 return std::less<element_type*>()(__lhs.get(), __rhs.get()); 01522 } 01523 }; 01524 01525 template<typename _Tp, _Lock_policy _Lp> 01526 struct less<__shared_ptr<_Tp, _Lp>> 01527 : public _Sp_less<__shared_ptr<_Tp, _Lp>> 01528 { }; 01529 01530 // 20.7.2.2.8 shared_ptr specialized algorithms. 01531 template<typename _Tp, _Lock_policy _Lp> 01532 inline void 01533 swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept 01534 { __a.swap(__b); } 01535 01536 // 20.7.2.2.9 shared_ptr casts 01537 01538 // The seemingly equivalent code: 01539 // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get())) 01540 // will eventually result in undefined behaviour, attempting to 01541 // delete the same object twice. 01542 /// static_pointer_cast 01543 template<typename _Tp, typename _Tp1, _Lock_policy _Lp> 01544 inline __shared_ptr<_Tp, _Lp> 01545 static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept 01546 { 01547 using _Sp = __shared_ptr<_Tp, _Lp>; 01548 return _Sp(__r, static_cast<typename _Sp::element_type*>(__r.get())); 01549 } 01550 01551 // The seemingly equivalent code: 01552 // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get())) 01553 // will eventually result in undefined behaviour, attempting to 01554 // delete the same object twice. 01555 /// const_pointer_cast 01556 template<typename _Tp, typename _Tp1, _Lock_policy _Lp> 01557 inline __shared_ptr<_Tp, _Lp> 01558 const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept 01559 { 01560 using _Sp = __shared_ptr<_Tp, _Lp>; 01561 return _Sp(__r, const_cast<typename _Sp::element_type*>(__r.get())); 01562 } 01563 01564 // The seemingly equivalent code: 01565 // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get())) 01566 // will eventually result in undefined behaviour, attempting to 01567 // delete the same object twice. 01568 /// dynamic_pointer_cast 01569 template<typename _Tp, typename _Tp1, _Lock_policy _Lp> 01570 inline __shared_ptr<_Tp, _Lp> 01571 dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept 01572 { 01573 using _Sp = __shared_ptr<_Tp, _Lp>; 01574 if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get())) 01575 return _Sp(__r, __p); 01576 return _Sp(); 01577 } 01578 01579 #if __cplusplus > 201402L 01580 template<typename _Tp, typename _Tp1, _Lock_policy _Lp> 01581 inline __shared_ptr<_Tp, _Lp> 01582 reinterpret_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept 01583 { 01584 using _Sp = __shared_ptr<_Tp, _Lp>; 01585 return _Sp(__r, reinterpret_cast<typename _Sp::element_type*>(__r.get())); 01586 } 01587 #endif 01588 01589 template<typename _Tp, _Lock_policy _Lp> 01590 class __weak_ptr 01591 { 01592 template<typename _Yp, typename _Res = void> 01593 using _Compatible = typename 01594 enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type; 01595 01596 // Constraint for assignment from shared_ptr and weak_ptr: 01597 template<typename _Yp> 01598 using _Assignable = _Compatible<_Yp, __weak_ptr&>; 01599 01600 public: 01601 using element_type = typename remove_extent<_Tp>::type; 01602 01603 constexpr __weak_ptr() noexcept 01604 : _M_ptr(nullptr), _M_refcount() 01605 { } 01606 01607 __weak_ptr(const __weak_ptr&) noexcept = default; 01608 01609 ~__weak_ptr() = default; 01610 01611 // The "obvious" converting constructor implementation: 01612 // 01613 // template<typename _Tp1> 01614 // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r) 01615 // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws 01616 // { } 01617 // 01618 // has a serious problem. 01619 // 01620 // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr) 01621 // conversion may require access to *__r._M_ptr (virtual inheritance). 01622 // 01623 // It is not possible to avoid spurious access violations since 01624 // in multithreaded programs __r._M_ptr may be invalidated at any point. 01625 template<typename _Yp, typename = _Compatible<_Yp>> 01626 __weak_ptr(const __weak_ptr<_Yp, _Lp>& __r) noexcept 01627 : _M_refcount(__r._M_refcount) 01628 { _M_ptr = __r.lock().get(); } 01629 01630 template<typename _Yp, typename = _Compatible<_Yp>> 01631 __weak_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept 01632 : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) 01633 { } 01634 01635 __weak_ptr(__weak_ptr&& __r) noexcept 01636 : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount)) 01637 { __r._M_ptr = nullptr; } 01638 01639 template<typename _Yp, typename = _Compatible<_Yp>> 01640 __weak_ptr(__weak_ptr<_Yp, _Lp>&& __r) noexcept 01641 : _M_ptr(__r.lock().get()), _M_refcount(std::move(__r._M_refcount)) 01642 { __r._M_ptr = nullptr; } 01643 01644 __weak_ptr& 01645 operator=(const __weak_ptr& __r) noexcept = default; 01646 01647 template<typename _Yp> 01648 _Assignable<_Yp> 01649 operator=(const __weak_ptr<_Yp, _Lp>& __r) noexcept 01650 { 01651 _M_ptr = __r.lock().get(); 01652 _M_refcount = __r._M_refcount; 01653 return *this; 01654 } 01655 01656 template<typename _Yp> 01657 _Assignable<_Yp> 01658 operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept 01659 { 01660 _M_ptr = __r._M_ptr; 01661 _M_refcount = __r._M_refcount; 01662 return *this; 01663 } 01664 01665 __weak_ptr& 01666 operator=(__weak_ptr&& __r) noexcept 01667 { 01668 _M_ptr = __r._M_ptr; 01669 _M_refcount = std::move(__r._M_refcount); 01670 __r._M_ptr = nullptr; 01671 return *this; 01672 } 01673 01674 template<typename _Yp> 01675 _Assignable<_Yp> 01676 operator=(__weak_ptr<_Yp, _Lp>&& __r) noexcept 01677 { 01678 _M_ptr = __r.lock().get(); 01679 _M_refcount = std::move(__r._M_refcount); 01680 __r._M_ptr = nullptr; 01681 return *this; 01682 } 01683 01684 __shared_ptr<_Tp, _Lp> 01685 lock() const noexcept 01686 { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); } 01687 01688 long 01689 use_count() const noexcept 01690 { return _M_refcount._M_get_use_count(); } 01691 01692 bool 01693 expired() const noexcept 01694 { return _M_refcount._M_get_use_count() == 0; } 01695 01696 template<typename _Tp1> 01697 bool 01698 owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const noexcept 01699 { return _M_refcount._M_less(__rhs._M_refcount); } 01700 01701 template<typename _Tp1> 01702 bool 01703 owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const noexcept 01704 { return _M_refcount._M_less(__rhs._M_refcount); } 01705 01706 void 01707 reset() noexcept 01708 { __weak_ptr().swap(*this); } 01709 01710 void 01711 swap(__weak_ptr& __s) noexcept 01712 { 01713 std::swap(_M_ptr, __s._M_ptr); 01714 _M_refcount._M_swap(__s._M_refcount); 01715 } 01716 01717 private: 01718 // Used by __enable_shared_from_this. 01719 void 01720 _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept 01721 { 01722 if (use_count() == 0) 01723 { 01724 _M_ptr = __ptr; 01725 _M_refcount = __refcount; 01726 } 01727 } 01728 01729 template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; 01730 template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; 01731 friend class __enable_shared_from_this<_Tp, _Lp>; 01732 friend class enable_shared_from_this<_Tp>; 01733 01734 element_type* _M_ptr; // Contained pointer. 01735 __weak_count<_Lp> _M_refcount; // Reference counter. 01736 }; 01737 01738 // 20.7.2.3.6 weak_ptr specialized algorithms. 01739 template<typename _Tp, _Lock_policy _Lp> 01740 inline void 01741 swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept 01742 { __a.swap(__b); } 01743 01744 template<typename _Tp, typename _Tp1> 01745 struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool> 01746 { 01747 bool 01748 operator()(const _Tp& __lhs, const _Tp& __rhs) const noexcept 01749 { return __lhs.owner_before(__rhs); } 01750 01751 bool 01752 operator()(const _Tp& __lhs, const _Tp1& __rhs) const noexcept 01753 { return __lhs.owner_before(__rhs); } 01754 01755 bool 01756 operator()(const _Tp1& __lhs, const _Tp& __rhs) const noexcept 01757 { return __lhs.owner_before(__rhs); } 01758 }; 01759 01760 template<> 01761 struct _Sp_owner_less<void, void> 01762 { 01763 template<typename _Tp, typename _Up> 01764 auto 01765 operator()(const _Tp& __lhs, const _Up& __rhs) const noexcept 01766 -> decltype(__lhs.owner_before(__rhs)) 01767 { return __lhs.owner_before(__rhs); } 01768 01769 using is_transparent = void; 01770 }; 01771 01772 template<typename _Tp, _Lock_policy _Lp> 01773 struct owner_less<__shared_ptr<_Tp, _Lp>> 01774 : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>> 01775 { }; 01776 01777 template<typename _Tp, _Lock_policy _Lp> 01778 struct owner_less<__weak_ptr<_Tp, _Lp>> 01779 : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>> 01780 { }; 01781 01782 01783 template<typename _Tp, _Lock_policy _Lp> 01784 class __enable_shared_from_this 01785 { 01786 protected: 01787 constexpr __enable_shared_from_this() noexcept { } 01788 01789 __enable_shared_from_this(const __enable_shared_from_this&) noexcept { } 01790 01791 __enable_shared_from_this& 01792 operator=(const __enable_shared_from_this&) noexcept 01793 { return *this; } 01794 01795 ~__enable_shared_from_this() { } 01796 01797 public: 01798 __shared_ptr<_Tp, _Lp> 01799 shared_from_this() 01800 { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); } 01801 01802 __shared_ptr<const _Tp, _Lp> 01803 shared_from_this() const 01804 { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); } 01805 01806 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 01807 __weak_ptr<_Tp, _Lp> 01808 weak_from_this() noexcept 01809 { return this->_M_weak_this; } 01810 01811 __weak_ptr<const _Tp, _Lp> 01812 weak_from_this() const noexcept 01813 { return this->_M_weak_this; } 01814 #endif 01815 01816 private: 01817 template<typename _Tp1> 01818 void 01819 _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept 01820 { _M_weak_this._M_assign(__p, __n); } 01821 01822 friend const __enable_shared_from_this* 01823 __enable_shared_from_this_base(const __shared_count<_Lp>&, 01824 const __enable_shared_from_this* __p) 01825 { return __p; } 01826 01827 template<typename, _Lock_policy> 01828 friend class __shared_ptr; 01829 01830 mutable __weak_ptr<_Tp, _Lp> _M_weak_this; 01831 }; 01832 01833 template<typename _Tp, _Lock_policy _Lp, typename _Alloc, typename... _Args> 01834 inline __shared_ptr<_Tp, _Lp> 01835 __allocate_shared(const _Alloc& __a, _Args&&... __args) 01836 { 01837 return __shared_ptr<_Tp, _Lp>(_Sp_make_shared_tag(), __a, 01838 std::forward<_Args>(__args)...); 01839 } 01840 01841 template<typename _Tp, _Lock_policy _Lp, typename... _Args> 01842 inline __shared_ptr<_Tp, _Lp> 01843 __make_shared(_Args&&... __args) 01844 { 01845 typedef typename std::remove_const<_Tp>::type _Tp_nc; 01846 return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(), 01847 std::forward<_Args>(__args)...); 01848 } 01849 01850 /// std::hash specialization for __shared_ptr. 01851 template<typename _Tp, _Lock_policy _Lp> 01852 struct hash<__shared_ptr<_Tp, _Lp>> 01853 : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>> 01854 { 01855 size_t 01856 operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept 01857 { 01858 return hash<typename __shared_ptr<_Tp, _Lp>::element_type*>()( 01859 __s.get()); 01860 } 01861 }; 01862 01863 _GLIBCXX_END_NAMESPACE_VERSION 01864 } // namespace 01865 01866 #endif // _SHARED_PTR_BASE_H