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1 : // shared_ptr and weak_ptr implementation details -*- C++ -*-
2 :
3 : // Copyright (C) 2007-2019 Free Software Foundation, Inc.
4 : //
5 : // This file is part of the GNU ISO C++ Library. This library is free
6 : // software; you can redistribute it and/or modify it under the
7 : // terms of the GNU General Public License as published by the
8 : // Free Software Foundation; either version 3, or (at your option)
9 : // any later version.
10 :
11 : // This library is distributed in the hope that it will be useful,
12 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 : // GNU General Public License for more details.
15 :
16 : // Under Section 7 of GPL version 3, you are granted additional
17 : // permissions described in the GCC Runtime Library Exception, version
18 : // 3.1, as published by the Free Software Foundation.
19 :
20 : // You should have received a copy of the GNU General Public License and
21 : // a copy of the GCC Runtime Library Exception along with this program;
22 : // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 : // <http://www.gnu.org/licenses/>.
24 :
25 : // GCC Note: Based on files from version 1.32.0 of the Boost library.
26 :
27 : // shared_count.hpp
28 : // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
29 :
30 : // shared_ptr.hpp
31 : // Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes.
32 : // Copyright (C) 2001, 2002, 2003 Peter Dimov
33 :
34 : // weak_ptr.hpp
35 : // Copyright (C) 2001, 2002, 2003 Peter Dimov
36 :
37 : // enable_shared_from_this.hpp
38 : // Copyright (C) 2002 Peter Dimov
39 :
40 : // Distributed under the Boost Software License, Version 1.0. (See
41 : // accompanying file LICENSE_1_0.txt or copy at
42 : // http://www.boost.org/LICENSE_1_0.txt)
43 :
44 : /** @file bits/shared_ptr_base.h
45 : * This is an internal header file, included by other library headers.
46 : * Do not attempt to use it directly. @headername{memory}
47 : */
48 :
49 : #ifndef _SHARED_PTR_BASE_H
50 : #define _SHARED_PTR_BASE_H 1
51 :
52 : #include <typeinfo>
53 : #include <bits/allocated_ptr.h>
54 : #include <bits/refwrap.h>
55 : #include <bits/stl_function.h>
56 : #include <ext/aligned_buffer.h>
57 :
58 : namespace std _GLIBCXX_VISIBILITY(default)
59 : {
60 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
61 :
62 : #if _GLIBCXX_USE_DEPRECATED
63 : #pragma GCC diagnostic push
64 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
65 : template<typename> class auto_ptr;
66 : #pragma GCC diagnostic pop
67 : #endif
68 :
69 : /**
70 : * @brief Exception possibly thrown by @c shared_ptr.
71 : * @ingroup exceptions
72 : */
73 : class bad_weak_ptr : public std::exception
74 : {
75 : public:
76 : virtual char const* what() const noexcept;
77 :
78 : virtual ~bad_weak_ptr() noexcept;
79 : };
80 :
81 : // Substitute for bad_weak_ptr object in the case of -fno-exceptions.
82 : inline void
83 : __throw_bad_weak_ptr()
84 : { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); }
85 :
86 : using __gnu_cxx::_Lock_policy;
87 : using __gnu_cxx::__default_lock_policy;
88 : using __gnu_cxx::_S_single;
89 : using __gnu_cxx::_S_mutex;
90 : using __gnu_cxx::_S_atomic;
91 :
92 : // Empty helper class except when the template argument is _S_mutex.
93 : template<_Lock_policy _Lp>
94 : class _Mutex_base
95 : {
96 : protected:
97 : // The atomic policy uses fully-fenced builtins, single doesn't care.
98 : enum { _S_need_barriers = 0 };
99 : };
100 :
101 : template<>
102 : class _Mutex_base<_S_mutex>
103 : : public __gnu_cxx::__mutex
104 : {
105 : protected:
106 : // This policy is used when atomic builtins are not available.
107 : // The replacement atomic operations might not have the necessary
108 : // memory barriers.
109 : enum { _S_need_barriers = 1 };
110 : };
111 :
112 : template<_Lock_policy _Lp = __default_lock_policy>
113 : class _Sp_counted_base
114 : : public _Mutex_base<_Lp>
115 : {
116 : public:
117 955 : _Sp_counted_base() noexcept
118 955 : : _M_use_count(1), _M_weak_count(1) { }
119 :
120 : virtual
121 0 : ~_Sp_counted_base() noexcept
122 : { }
123 :
124 : // Called when _M_use_count drops to zero, to release the resources
125 : // managed by *this.
126 : virtual void
127 : _M_dispose() noexcept = 0;
128 :
129 : // Called when _M_weak_count drops to zero.
130 : virtual void
131 0 : _M_destroy() noexcept
132 0 : { delete this; }
133 :
134 : virtual void*
135 : _M_get_deleter(const std::type_info&) noexcept = 0;
136 :
137 : void
138 : _M_add_ref_copy()
139 : { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); }
140 :
141 : void
142 : _M_add_ref_lock();
143 :
144 : bool
145 : _M_add_ref_lock_nothrow();
146 :
147 : void
148 955 : _M_release() noexcept
149 : {
150 : // Be race-detector-friendly. For more info see bits/c++config.
151 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count);
152 1910 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
153 : {
154 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
155 955 : _M_dispose();
156 : // There must be a memory barrier between dispose() and destroy()
157 : // to ensure that the effects of dispose() are observed in the
158 : // thread that runs destroy().
159 : // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html
160 : if (_Mutex_base<_Lp>::_S_need_barriers)
161 : {
162 : __atomic_thread_fence (__ATOMIC_ACQ_REL);
163 : }
164 :
165 : // Be race-detector-friendly. For more info see bits/c++config.
166 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
167 1910 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count,
168 : -1) == 1)
169 : {
170 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
171 955 : _M_destroy();
172 : }
173 : }
174 955 : }
175 :
176 : void
177 : _M_weak_add_ref() noexcept
178 : { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); }
179 :
180 : void
181 : _M_weak_release() noexcept
182 : {
183 : // Be race-detector-friendly. For more info see bits/c++config.
184 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
185 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1)
186 : {
187 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
188 : if (_Mutex_base<_Lp>::_S_need_barriers)
189 : {
190 : // See _M_release(),
191 : // destroy() must observe results of dispose()
192 : __atomic_thread_fence (__ATOMIC_ACQ_REL);
193 : }
194 : _M_destroy();
195 : }
196 : }
197 :
198 : long
199 : _M_get_use_count() const noexcept
200 : {
201 : // No memory barrier is used here so there is no synchronization
202 : // with other threads.
203 : return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED);
204 : }
205 :
206 : private:
207 : _Sp_counted_base(_Sp_counted_base const&) = delete;
208 : _Sp_counted_base& operator=(_Sp_counted_base const&) = delete;
209 :
210 : _Atomic_word _M_use_count; // #shared
211 : _Atomic_word _M_weak_count; // #weak + (#shared != 0)
212 : };
213 :
214 : template<>
215 : inline void
216 : _Sp_counted_base<_S_single>::
217 : _M_add_ref_lock()
218 : {
219 : if (_M_use_count == 0)
220 : __throw_bad_weak_ptr();
221 : ++_M_use_count;
222 : }
223 :
224 : template<>
225 : inline void
226 : _Sp_counted_base<_S_mutex>::
227 : _M_add_ref_lock()
228 : {
229 : __gnu_cxx::__scoped_lock sentry(*this);
230 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
231 : {
232 : _M_use_count = 0;
233 : __throw_bad_weak_ptr();
234 : }
235 : }
236 :
237 : template<>
238 : inline void
239 : _Sp_counted_base<_S_atomic>::
240 : _M_add_ref_lock()
241 : {
242 : // Perform lock-free add-if-not-zero operation.
243 : _Atomic_word __count = _M_get_use_count();
244 : do
245 : {
246 : if (__count == 0)
247 : __throw_bad_weak_ptr();
248 : // Replace the current counter value with the old value + 1, as
249 : // long as it's not changed meanwhile.
250 : }
251 : while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
252 : true, __ATOMIC_ACQ_REL,
253 : __ATOMIC_RELAXED));
254 : }
255 :
256 : template<>
257 : inline bool
258 : _Sp_counted_base<_S_single>::
259 : _M_add_ref_lock_nothrow()
260 : {
261 : if (_M_use_count == 0)
262 : return false;
263 : ++_M_use_count;
264 : return true;
265 : }
266 :
267 : template<>
268 : inline bool
269 : _Sp_counted_base<_S_mutex>::
270 : _M_add_ref_lock_nothrow()
271 : {
272 : __gnu_cxx::__scoped_lock sentry(*this);
273 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
274 : {
275 : _M_use_count = 0;
276 : return false;
277 : }
278 : return true;
279 : }
280 :
281 : template<>
282 : inline bool
283 : _Sp_counted_base<_S_atomic>::
284 : _M_add_ref_lock_nothrow()
285 : {
286 : // Perform lock-free add-if-not-zero operation.
287 : _Atomic_word __count = _M_get_use_count();
288 : do
289 : {
290 : if (__count == 0)
291 : return false;
292 : // Replace the current counter value with the old value + 1, as
293 : // long as it's not changed meanwhile.
294 : }
295 : while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
296 : true, __ATOMIC_ACQ_REL,
297 : __ATOMIC_RELAXED));
298 : return true;
299 : }
300 :
301 : template<>
302 : inline void
303 : _Sp_counted_base<_S_single>::_M_add_ref_copy()
304 : { ++_M_use_count; }
305 :
306 : template<>
307 : inline void
308 : _Sp_counted_base<_S_single>::_M_release() noexcept
309 : {
310 : if (--_M_use_count == 0)
311 : {
312 : _M_dispose();
313 : if (--_M_weak_count == 0)
314 : _M_destroy();
315 : }
316 : }
317 :
318 : template<>
319 : inline void
320 : _Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept
321 : { ++_M_weak_count; }
322 :
323 : template<>
324 : inline void
325 : _Sp_counted_base<_S_single>::_M_weak_release() noexcept
326 : {
327 : if (--_M_weak_count == 0)
328 : _M_destroy();
329 : }
330 :
331 : template<>
332 : inline long
333 : _Sp_counted_base<_S_single>::_M_get_use_count() const noexcept
334 : { return _M_use_count; }
335 :
336 :
337 : // Forward declarations.
338 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
339 : class __shared_ptr;
340 :
341 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
342 : class __weak_ptr;
343 :
344 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
345 : class __enable_shared_from_this;
346 :
347 : template<typename _Tp>
348 : class shared_ptr;
349 :
350 : template<typename _Tp>
351 : class weak_ptr;
352 :
353 : template<typename _Tp>
354 : struct owner_less;
355 :
356 : template<typename _Tp>
357 : class enable_shared_from_this;
358 :
359 : template<_Lock_policy _Lp = __default_lock_policy>
360 : class __weak_count;
361 :
362 : template<_Lock_policy _Lp = __default_lock_policy>
363 : class __shared_count;
364 :
365 :
366 : // Counted ptr with no deleter or allocator support
367 : template<typename _Ptr, _Lock_policy _Lp>
368 : class _Sp_counted_ptr final : public _Sp_counted_base<_Lp>
369 : {
370 : public:
371 : explicit
372 : _Sp_counted_ptr(_Ptr __p) noexcept
373 : : _M_ptr(__p) { }
374 :
375 : virtual void
376 : _M_dispose() noexcept
377 : { delete _M_ptr; }
378 :
379 : virtual void
380 : _M_destroy() noexcept
381 : { delete this; }
382 :
383 : virtual void*
384 : _M_get_deleter(const std::type_info&) noexcept
385 : { return nullptr; }
386 :
387 : _Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
388 : _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
389 :
390 : private:
391 : _Ptr _M_ptr;
392 : };
393 :
394 : template<>
395 : inline void
396 : _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { }
397 :
398 : template<>
399 : inline void
400 : _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { }
401 :
402 : template<>
403 : inline void
404 0 : _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { }
405 :
406 : template<int _Nm, typename _Tp,
407 : bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
408 : struct _Sp_ebo_helper;
409 :
410 : /// Specialization using EBO.
411 : template<int _Nm, typename _Tp>
412 955 : struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp
413 : {
414 955 : explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { }
415 : explicit _Sp_ebo_helper(_Tp&& __tp) : _Tp(std::move(__tp)) { }
416 :
417 : static _Tp&
418 1910 : _S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); }
419 : };
420 :
421 : /// Specialization not using EBO.
422 : template<int _Nm, typename _Tp>
423 : struct _Sp_ebo_helper<_Nm, _Tp, false>
424 : {
425 : explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { }
426 : explicit _Sp_ebo_helper(_Tp&& __tp) : _M_tp(std::move(__tp)) { }
427 :
428 : static _Tp&
429 : _S_get(_Sp_ebo_helper& __eboh)
430 : { return __eboh._M_tp; }
431 :
432 : private:
433 : _Tp _M_tp;
434 : };
435 :
436 : // Support for custom deleter and/or allocator
437 : template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
438 : class _Sp_counted_deleter final : public _Sp_counted_base<_Lp>
439 : {
440 : class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc>
441 : {
442 : typedef _Sp_ebo_helper<0, _Deleter> _Del_base;
443 : typedef _Sp_ebo_helper<1, _Alloc> _Alloc_base;
444 :
445 : public:
446 : _Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
447 : : _M_ptr(__p), _Del_base(std::move(__d)), _Alloc_base(__a)
448 : { }
449 :
450 : _Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); }
451 : _Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); }
452 :
453 : _Ptr _M_ptr;
454 : };
455 :
456 : public:
457 : using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_deleter>;
458 :
459 : // __d(__p) must not throw.
460 : _Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept
461 : : _M_impl(__p, std::move(__d), _Alloc()) { }
462 :
463 : // __d(__p) must not throw.
464 : _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
465 : : _M_impl(__p, std::move(__d), __a) { }
466 :
467 : ~_Sp_counted_deleter() noexcept { }
468 :
469 : virtual void
470 : _M_dispose() noexcept
471 : { _M_impl._M_del()(_M_impl._M_ptr); }
472 :
473 : virtual void
474 : _M_destroy() noexcept
475 : {
476 : __allocator_type __a(_M_impl._M_alloc());
477 : __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
478 : this->~_Sp_counted_deleter();
479 : }
480 :
481 : virtual void*
482 : _M_get_deleter(const std::type_info& __ti) noexcept
483 : {
484 : #if __cpp_rtti
485 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
486 : // 2400. shared_ptr's get_deleter() should use addressof()
487 : return __ti == typeid(_Deleter)
488 : ? std::__addressof(_M_impl._M_del())
489 : : nullptr;
490 : #else
491 : return nullptr;
492 : #endif
493 : }
494 :
495 : private:
496 : _Impl _M_impl;
497 : };
498 :
499 : // helpers for make_shared / allocate_shared
500 :
501 : struct _Sp_make_shared_tag
502 : {
503 : private:
504 : template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
505 : friend class _Sp_counted_ptr_inplace;
506 :
507 : static const type_info&
508 0 : _S_ti() noexcept _GLIBCXX_VISIBILITY(default)
509 : {
510 0 : alignas(type_info) static constexpr char __tag[sizeof(type_info)] = { };
511 0 : return reinterpret_cast<const type_info&>(__tag);
512 : }
513 :
514 : static bool _S_eq(const type_info&) noexcept;
515 : };
516 :
517 : template<typename _Alloc>
518 : struct _Sp_alloc_shared_tag
519 : {
520 : const _Alloc& _M_a;
521 : };
522 :
523 : template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
524 : class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp>
525 : {
526 955 : class _Impl : _Sp_ebo_helper<0, _Alloc>
527 : {
528 : typedef _Sp_ebo_helper<0, _Alloc> _A_base;
529 :
530 : public:
531 955 : explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { }
532 :
533 1910 : _Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); }
534 :
535 : __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
536 : };
537 :
538 : public:
539 : using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
540 :
541 : // Alloc parameter is not a reference so doesn't alias anything in __args
542 : template<typename... _Args>
543 955 : _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
544 955 : : _M_impl(__a)
545 : {
546 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
547 : // 2070. allocate_shared should use allocator_traits<A>::construct
548 1910 : allocator_traits<_Alloc>::construct(__a, _M_ptr(),
549 : std::forward<_Args>(__args)...); // might throw
550 : }
551 :
552 955 : ~_Sp_counted_ptr_inplace() noexcept { }
553 :
554 : virtual void
555 955 : _M_dispose() noexcept
556 : {
557 955 : allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr());
558 955 : }
559 :
560 : // Override because the allocator needs to know the dynamic type
561 : virtual void
562 955 : _M_destroy() noexcept
563 : {
564 955 : __allocator_type __a(_M_impl._M_alloc());
565 955 : __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
566 955 : this->~_Sp_counted_ptr_inplace();
567 955 : }
568 :
569 : private:
570 : friend class __shared_count<_Lp>; // To be able to call _M_ptr().
571 :
572 : // No longer used, but code compiled against old libstdc++ headers
573 : // might still call it from __shared_ptr ctor to get the pointer out.
574 : virtual void*
575 0 : _M_get_deleter(const std::type_info& __ti) noexcept override
576 : {
577 0 : auto __ptr = const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
578 : // Check for the fake type_info first, so we don't try to access it
579 : // as a real type_info object. Otherwise, check if it's the real
580 : // type_info for this class. With RTTI enabled we can check directly,
581 : // or call a library function to do it.
582 : if (&__ti == &_Sp_make_shared_tag::_S_ti()
583 0 : ||
584 : #if __cpp_rtti
585 0 : __ti == typeid(_Sp_make_shared_tag)
586 : #else
587 : _Sp_make_shared_tag::_S_eq(__ti)
588 : #endif
589 : )
590 0 : return __ptr;
591 : return nullptr;
592 : }
593 :
594 1910 : _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); }
595 :
596 : _Impl _M_impl;
597 : };
598 :
599 : // The default deleter for shared_ptr<T[]> and shared_ptr<T[N]>.
600 : struct __sp_array_delete
601 : {
602 : template<typename _Yp>
603 : void operator()(_Yp* __p) const { delete[] __p; }
604 : };
605 :
606 : template<_Lock_policy _Lp>
607 : class __shared_count
608 : {
609 : template<typename _Tp>
610 : struct __not_alloc_shared_tag { using type = void; };
611 :
612 : template<typename _Tp>
613 : struct __not_alloc_shared_tag<_Sp_alloc_shared_tag<_Tp>> { };
614 :
615 : public:
616 955 : constexpr __shared_count() noexcept : _M_pi(0)
617 : { }
618 :
619 : template<typename _Ptr>
620 : explicit
621 : __shared_count(_Ptr __p) : _M_pi(0)
622 : {
623 : __try
624 : {
625 : _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
626 : }
627 : __catch(...)
628 : {
629 : delete __p;
630 : __throw_exception_again;
631 : }
632 : }
633 :
634 : template<typename _Ptr>
635 : __shared_count(_Ptr __p, /* is_array = */ false_type)
636 : : __shared_count(__p)
637 : { }
638 :
639 : template<typename _Ptr>
640 : __shared_count(_Ptr __p, /* is_array = */ true_type)
641 : : __shared_count(__p, __sp_array_delete{}, allocator<void>())
642 : { }
643 :
644 : template<typename _Ptr, typename _Deleter,
645 : typename = typename __not_alloc_shared_tag<_Deleter>::type>
646 : __shared_count(_Ptr __p, _Deleter __d)
647 : : __shared_count(__p, std::move(__d), allocator<void>())
648 : { }
649 :
650 : template<typename _Ptr, typename _Deleter, typename _Alloc,
651 : typename = typename __not_alloc_shared_tag<_Deleter>::type>
652 : __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
653 : {
654 : typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
655 : __try
656 : {
657 : typename _Sp_cd_type::__allocator_type __a2(__a);
658 : auto __guard = std::__allocate_guarded(__a2);
659 : _Sp_cd_type* __mem = __guard.get();
660 : ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a));
661 : _M_pi = __mem;
662 : __guard = nullptr;
663 : }
664 : __catch(...)
665 : {
666 : __d(__p); // Call _Deleter on __p.
667 : __throw_exception_again;
668 : }
669 : }
670 :
671 : template<typename _Tp, typename _Alloc, typename... _Args>
672 955 : __shared_count(_Tp*& __p, _Sp_alloc_shared_tag<_Alloc> __a,
673 : _Args&&... __args)
674 : {
675 : typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
676 955 : typename _Sp_cp_type::__allocator_type __a2(__a._M_a);
677 1910 : auto __guard = std::__allocate_guarded(__a2);
678 955 : _Sp_cp_type* __mem = __guard.get();
679 955 : auto __pi = ::new (__mem)
680 955 : _Sp_cp_type(__a._M_a, std::forward<_Args>(__args)...);
681 955 : __guard = nullptr;
682 955 : _M_pi = __pi;
683 955 : __p = __pi->_M_ptr();
684 955 : }
685 :
686 : #if _GLIBCXX_USE_DEPRECATED
687 : #pragma GCC diagnostic push
688 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
689 : // Special case for auto_ptr<_Tp> to provide the strong guarantee.
690 : template<typename _Tp>
691 : explicit
692 : __shared_count(std::auto_ptr<_Tp>&& __r);
693 : #pragma GCC diagnostic pop
694 : #endif
695 :
696 : // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
697 : template<typename _Tp, typename _Del>
698 : explicit
699 : __shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0)
700 : {
701 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
702 : // 2415. Inconsistency between unique_ptr and shared_ptr
703 : if (__r.get() == nullptr)
704 : return;
705 :
706 : using _Ptr = typename unique_ptr<_Tp, _Del>::pointer;
707 : using _Del2 = typename conditional<is_reference<_Del>::value,
708 : reference_wrapper<typename remove_reference<_Del>::type>,
709 : _Del>::type;
710 : using _Sp_cd_type
711 : = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>;
712 : using _Alloc = allocator<_Sp_cd_type>;
713 : using _Alloc_traits = allocator_traits<_Alloc>;
714 : _Alloc __a;
715 : _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1);
716 : _Alloc_traits::construct(__a, __mem, __r.release(),
717 : __r.get_deleter()); // non-throwing
718 : _M_pi = __mem;
719 : }
720 :
721 : // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
722 : explicit __shared_count(const __weak_count<_Lp>& __r);
723 :
724 : // Does not throw if __r._M_get_use_count() == 0, caller must check.
725 : explicit __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t);
726 :
727 955 : ~__shared_count() noexcept
728 : {
729 955 : if (_M_pi != nullptr)
730 955 : _M_pi->_M_release();
731 : }
732 :
733 : __shared_count(const __shared_count& __r) noexcept
734 : : _M_pi(__r._M_pi)
735 : {
736 : if (_M_pi != 0)
737 : _M_pi->_M_add_ref_copy();
738 : }
739 :
740 : __shared_count&
741 : operator=(const __shared_count& __r) noexcept
742 : {
743 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
744 : if (__tmp != _M_pi)
745 : {
746 : if (__tmp != 0)
747 : __tmp->_M_add_ref_copy();
748 : if (_M_pi != 0)
749 : _M_pi->_M_release();
750 : _M_pi = __tmp;
751 : }
752 : return *this;
753 : }
754 :
755 : void
756 955 : _M_swap(__shared_count& __r) noexcept
757 : {
758 955 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
759 955 : __r._M_pi = _M_pi;
760 955 : _M_pi = __tmp;
761 : }
762 :
763 : long
764 : _M_get_use_count() const noexcept
765 : { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
766 :
767 : bool
768 : _M_unique() const noexcept
769 : { return this->_M_get_use_count() == 1; }
770 :
771 : void*
772 : _M_get_deleter(const std::type_info& __ti) const noexcept
773 : { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; }
774 :
775 : bool
776 : _M_less(const __shared_count& __rhs) const noexcept
777 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
778 :
779 : bool
780 : _M_less(const __weak_count<_Lp>& __rhs) const noexcept
781 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
782 :
783 : // Friend function injected into enclosing namespace and found by ADL
784 : friend inline bool
785 : operator==(const __shared_count& __a, const __shared_count& __b) noexcept
786 : { return __a._M_pi == __b._M_pi; }
787 :
788 : private:
789 : friend class __weak_count<_Lp>;
790 :
791 : _Sp_counted_base<_Lp>* _M_pi;
792 : };
793 :
794 :
795 : template<_Lock_policy _Lp>
796 : class __weak_count
797 : {
798 : public:
799 : constexpr __weak_count() noexcept : _M_pi(nullptr)
800 : { }
801 :
802 : __weak_count(const __shared_count<_Lp>& __r) noexcept
803 : : _M_pi(__r._M_pi)
804 : {
805 : if (_M_pi != nullptr)
806 : _M_pi->_M_weak_add_ref();
807 : }
808 :
809 : __weak_count(const __weak_count& __r) noexcept
810 : : _M_pi(__r._M_pi)
811 : {
812 : if (_M_pi != nullptr)
813 : _M_pi->_M_weak_add_ref();
814 : }
815 :
816 : __weak_count(__weak_count&& __r) noexcept
817 : : _M_pi(__r._M_pi)
818 : { __r._M_pi = nullptr; }
819 :
820 : ~__weak_count() noexcept
821 : {
822 : if (_M_pi != nullptr)
823 : _M_pi->_M_weak_release();
824 : }
825 :
826 : __weak_count&
827 : operator=(const __shared_count<_Lp>& __r) noexcept
828 : {
829 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
830 : if (__tmp != nullptr)
831 : __tmp->_M_weak_add_ref();
832 : if (_M_pi != nullptr)
833 : _M_pi->_M_weak_release();
834 : _M_pi = __tmp;
835 : return *this;
836 : }
837 :
838 : __weak_count&
839 : operator=(const __weak_count& __r) noexcept
840 : {
841 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
842 : if (__tmp != nullptr)
843 : __tmp->_M_weak_add_ref();
844 : if (_M_pi != nullptr)
845 : _M_pi->_M_weak_release();
846 : _M_pi = __tmp;
847 : return *this;
848 : }
849 :
850 : __weak_count&
851 : operator=(__weak_count&& __r) noexcept
852 : {
853 : if (_M_pi != nullptr)
854 : _M_pi->_M_weak_release();
855 : _M_pi = __r._M_pi;
856 : __r._M_pi = nullptr;
857 : return *this;
858 : }
859 :
860 : void
861 : _M_swap(__weak_count& __r) noexcept
862 : {
863 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
864 : __r._M_pi = _M_pi;
865 : _M_pi = __tmp;
866 : }
867 :
868 : long
869 : _M_get_use_count() const noexcept
870 : { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; }
871 :
872 : bool
873 : _M_less(const __weak_count& __rhs) const noexcept
874 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
875 :
876 : bool
877 : _M_less(const __shared_count<_Lp>& __rhs) const noexcept
878 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
879 :
880 : // Friend function injected into enclosing namespace and found by ADL
881 : friend inline bool
882 : operator==(const __weak_count& __a, const __weak_count& __b) noexcept
883 : { return __a._M_pi == __b._M_pi; }
884 :
885 : private:
886 : friend class __shared_count<_Lp>;
887 :
888 : _Sp_counted_base<_Lp>* _M_pi;
889 : };
890 :
891 : // Now that __weak_count is defined we can define this constructor:
892 : template<_Lock_policy _Lp>
893 : inline
894 : __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r)
895 : : _M_pi(__r._M_pi)
896 : {
897 : if (_M_pi != nullptr)
898 : _M_pi->_M_add_ref_lock();
899 : else
900 : __throw_bad_weak_ptr();
901 : }
902 :
903 : // Now that __weak_count is defined we can define this constructor:
904 : template<_Lock_policy _Lp>
905 : inline
906 : __shared_count<_Lp>::
907 : __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t)
908 : : _M_pi(__r._M_pi)
909 : {
910 : if (_M_pi != nullptr)
911 : if (!_M_pi->_M_add_ref_lock_nothrow())
912 : _M_pi = nullptr;
913 : }
914 :
915 : #define __cpp_lib_shared_ptr_arrays 201611L
916 :
917 : // Helper traits for shared_ptr of array:
918 :
919 : // A pointer type Y* is said to be compatible with a pointer type T* when
920 : // either Y* is convertible to T* or Y is U[N] and T is U cv [].
921 : template<typename _Yp_ptr, typename _Tp_ptr>
922 : struct __sp_compatible_with
923 : : false_type
924 : { };
925 :
926 : template<typename _Yp, typename _Tp>
927 : struct __sp_compatible_with<_Yp*, _Tp*>
928 : : is_convertible<_Yp*, _Tp*>::type
929 : { };
930 :
931 : template<typename _Up, size_t _Nm>
932 : struct __sp_compatible_with<_Up(*)[_Nm], _Up(*)[]>
933 : : true_type
934 : { };
935 :
936 : template<typename _Up, size_t _Nm>
937 : struct __sp_compatible_with<_Up(*)[_Nm], const _Up(*)[]>
938 : : true_type
939 : { };
940 :
941 : template<typename _Up, size_t _Nm>
942 : struct __sp_compatible_with<_Up(*)[_Nm], volatile _Up(*)[]>
943 : : true_type
944 : { };
945 :
946 : template<typename _Up, size_t _Nm>
947 : struct __sp_compatible_with<_Up(*)[_Nm], const volatile _Up(*)[]>
948 : : true_type
949 : { };
950 :
951 : // Test conversion from Y(*)[N] to U(*)[N] without forming invalid type Y[N].
952 : template<typename _Up, size_t _Nm, typename _Yp, typename = void>
953 : struct __sp_is_constructible_arrN
954 : : false_type
955 : { };
956 :
957 : template<typename _Up, size_t _Nm, typename _Yp>
958 : struct __sp_is_constructible_arrN<_Up, _Nm, _Yp, __void_t<_Yp[_Nm]>>
959 : : is_convertible<_Yp(*)[_Nm], _Up(*)[_Nm]>::type
960 : { };
961 :
962 : // Test conversion from Y(*)[] to U(*)[] without forming invalid type Y[].
963 : template<typename _Up, typename _Yp, typename = void>
964 : struct __sp_is_constructible_arr
965 : : false_type
966 : { };
967 :
968 : template<typename _Up, typename _Yp>
969 : struct __sp_is_constructible_arr<_Up, _Yp, __void_t<_Yp[]>>
970 : : is_convertible<_Yp(*)[], _Up(*)[]>::type
971 : { };
972 :
973 : // Trait to check if shared_ptr<T> can be constructed from Y*.
974 : template<typename _Tp, typename _Yp>
975 : struct __sp_is_constructible;
976 :
977 : // When T is U[N], Y(*)[N] shall be convertible to T*;
978 : template<typename _Up, size_t _Nm, typename _Yp>
979 : struct __sp_is_constructible<_Up[_Nm], _Yp>
980 : : __sp_is_constructible_arrN<_Up, _Nm, _Yp>::type
981 : { };
982 :
983 : // when T is U[], Y(*)[] shall be convertible to T*;
984 : template<typename _Up, typename _Yp>
985 : struct __sp_is_constructible<_Up[], _Yp>
986 : : __sp_is_constructible_arr<_Up, _Yp>::type
987 : { };
988 :
989 : // otherwise, Y* shall be convertible to T*.
990 : template<typename _Tp, typename _Yp>
991 : struct __sp_is_constructible
992 : : is_convertible<_Yp*, _Tp*>::type
993 : { };
994 :
995 :
996 : // Define operator* and operator-> for shared_ptr<T>.
997 : template<typename _Tp, _Lock_policy _Lp,
998 : bool = is_array<_Tp>::value, bool = is_void<_Tp>::value>
999 : class __shared_ptr_access
1000 : {
1001 : public:
1002 : using element_type = _Tp;
1003 :
1004 : element_type&
1005 7640 : operator*() const noexcept
1006 : {
1007 : __glibcxx_assert(_M_get() != nullptr);
1008 955 : return *_M_get();
1009 : }
1010 :
1011 : element_type*
1012 11460 : operator->() const noexcept
1013 : {
1014 : _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
1015 11460 : return _M_get();
1016 : }
1017 :
1018 : private:
1019 : element_type*
1020 18145 : _M_get() const noexcept
1021 18145 : { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
1022 : };
1023 :
1024 : // Define operator-> for shared_ptr<cv void>.
1025 : template<typename _Tp, _Lock_policy _Lp>
1026 : class __shared_ptr_access<_Tp, _Lp, false, true>
1027 : {
1028 : public:
1029 : using element_type = _Tp;
1030 :
1031 : element_type*
1032 : operator->() const noexcept
1033 : {
1034 : auto __ptr = static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get();
1035 : _GLIBCXX_DEBUG_PEDASSERT(__ptr != nullptr);
1036 : return __ptr;
1037 : }
1038 : };
1039 :
1040 : // Define operator[] for shared_ptr<T[]> and shared_ptr<T[N]>.
1041 : template<typename _Tp, _Lock_policy _Lp>
1042 : class __shared_ptr_access<_Tp, _Lp, true, false>
1043 : {
1044 : public:
1045 : using element_type = typename remove_extent<_Tp>::type;
1046 :
1047 : #if __cplusplus <= 201402L
1048 : [[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17")]]
1049 : element_type&
1050 : operator*() const noexcept
1051 : {
1052 : __glibcxx_assert(_M_get() != nullptr);
1053 : return *_M_get();
1054 : }
1055 :
1056 : [[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17")]]
1057 : element_type*
1058 : operator->() const noexcept
1059 : {
1060 : _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
1061 : return _M_get();
1062 : }
1063 : #endif
1064 :
1065 : element_type&
1066 : operator[](ptrdiff_t __i) const
1067 : {
1068 : __glibcxx_assert(_M_get() != nullptr);
1069 : __glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value);
1070 : return _M_get()[__i];
1071 : }
1072 :
1073 : private:
1074 : element_type*
1075 : _M_get() const noexcept
1076 : { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
1077 : };
1078 :
1079 : template<typename _Tp, _Lock_policy _Lp>
1080 : class __shared_ptr
1081 : : public __shared_ptr_access<_Tp, _Lp>
1082 : {
1083 : public:
1084 : using element_type = typename remove_extent<_Tp>::type;
1085 :
1086 : private:
1087 : // Constraint for taking ownership of a pointer of type _Yp*:
1088 : template<typename _Yp>
1089 : using _SafeConv
1090 : = typename enable_if<__sp_is_constructible<_Tp, _Yp>::value>::type;
1091 :
1092 : // Constraint for construction from shared_ptr and weak_ptr:
1093 : template<typename _Yp, typename _Res = void>
1094 : using _Compatible = typename
1095 : enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
1096 :
1097 : // Constraint for assignment from shared_ptr and weak_ptr:
1098 : template<typename _Yp>
1099 : using _Assignable = _Compatible<_Yp, __shared_ptr&>;
1100 :
1101 : // Constraint for construction from unique_ptr:
1102 : template<typename _Yp, typename _Del, typename _Res = void,
1103 : typename _Ptr = typename unique_ptr<_Yp, _Del>::pointer>
1104 : using _UniqCompatible = typename enable_if<__and_<
1105 : __sp_compatible_with<_Yp*, _Tp*>, is_convertible<_Ptr, element_type*>
1106 : >::value, _Res>::type;
1107 :
1108 : // Constraint for assignment from unique_ptr:
1109 : template<typename _Yp, typename _Del>
1110 : using _UniqAssignable = _UniqCompatible<_Yp, _Del, __shared_ptr&>;
1111 :
1112 : public:
1113 :
1114 : #if __cplusplus > 201402L
1115 : using weak_type = __weak_ptr<_Tp, _Lp>;
1116 : #endif
1117 :
1118 : constexpr __shared_ptr() noexcept
1119 : : _M_ptr(0), _M_refcount()
1120 : { }
1121 :
1122 : template<typename _Yp, typename = _SafeConv<_Yp>>
1123 : explicit
1124 : __shared_ptr(_Yp* __p)
1125 : : _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type())
1126 : {
1127 : static_assert( !is_void<_Yp>::value, "incomplete type" );
1128 : static_assert( sizeof(_Yp) > 0, "incomplete type" );
1129 : _M_enable_shared_from_this_with(__p);
1130 : }
1131 :
1132 : template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>>
1133 : __shared_ptr(_Yp* __p, _Deleter __d)
1134 : : _M_ptr(__p), _M_refcount(__p, std::move(__d))
1135 : {
1136 : static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
1137 : "deleter expression d(p) is well-formed");
1138 : _M_enable_shared_from_this_with(__p);
1139 : }
1140 :
1141 : template<typename _Yp, typename _Deleter, typename _Alloc,
1142 : typename = _SafeConv<_Yp>>
1143 : __shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a)
1144 : : _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a))
1145 : {
1146 : static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
1147 : "deleter expression d(p) is well-formed");
1148 : _M_enable_shared_from_this_with(__p);
1149 : }
1150 :
1151 : template<typename _Deleter>
1152 : __shared_ptr(nullptr_t __p, _Deleter __d)
1153 : : _M_ptr(0), _M_refcount(__p, std::move(__d))
1154 : { }
1155 :
1156 : template<typename _Deleter, typename _Alloc>
1157 : __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
1158 : : _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a))
1159 : { }
1160 :
1161 : template<typename _Yp>
1162 : __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r,
1163 : element_type* __p) noexcept
1164 : : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
1165 : { }
1166 :
1167 : __shared_ptr(const __shared_ptr&) noexcept = default;
1168 : __shared_ptr& operator=(const __shared_ptr&) noexcept = default;
1169 1910 : ~__shared_ptr() = default;
1170 :
1171 : template<typename _Yp, typename = _Compatible<_Yp>>
1172 : __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1173 : : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1174 : { }
1175 :
1176 : __shared_ptr(__shared_ptr&& __r) noexcept
1177 : : _M_ptr(__r._M_ptr), _M_refcount()
1178 : {
1179 : _M_refcount._M_swap(__r._M_refcount);
1180 : __r._M_ptr = 0;
1181 : }
1182 :
1183 : template<typename _Yp, typename = _Compatible<_Yp>>
1184 955 : __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r) noexcept
1185 955 : : _M_ptr(__r._M_ptr), _M_refcount()
1186 : {
1187 955 : _M_refcount._M_swap(__r._M_refcount);
1188 955 : __r._M_ptr = 0;
1189 : }
1190 :
1191 : template<typename _Yp, typename = _Compatible<_Yp>>
1192 : explicit __shared_ptr(const __weak_ptr<_Yp, _Lp>& __r)
1193 : : _M_refcount(__r._M_refcount) // may throw
1194 : {
1195 : // It is now safe to copy __r._M_ptr, as
1196 : // _M_refcount(__r._M_refcount) did not throw.
1197 : _M_ptr = __r._M_ptr;
1198 : }
1199 :
1200 : // If an exception is thrown this constructor has no effect.
1201 : template<typename _Yp, typename _Del,
1202 : typename = _UniqCompatible<_Yp, _Del>>
1203 : __shared_ptr(unique_ptr<_Yp, _Del>&& __r)
1204 : : _M_ptr(__r.get()), _M_refcount()
1205 : {
1206 : auto __raw = __to_address(__r.get());
1207 : _M_refcount = __shared_count<_Lp>(std::move(__r));
1208 : _M_enable_shared_from_this_with(__raw);
1209 : }
1210 :
1211 : #if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED
1212 : protected:
1213 : // If an exception is thrown this constructor has no effect.
1214 : template<typename _Tp1, typename _Del,
1215 : typename enable_if<__and_<
1216 : __not_<is_array<_Tp>>, is_array<_Tp1>,
1217 : is_convertible<typename unique_ptr<_Tp1, _Del>::pointer, _Tp*>
1218 : >::value, bool>::type = true>
1219 : __shared_ptr(unique_ptr<_Tp1, _Del>&& __r, __sp_array_delete)
1220 : : _M_ptr(__r.get()), _M_refcount()
1221 : {
1222 : auto __raw = __to_address(__r.get());
1223 : _M_refcount = __shared_count<_Lp>(std::move(__r));
1224 : _M_enable_shared_from_this_with(__raw);
1225 : }
1226 : public:
1227 : #endif
1228 :
1229 : #if _GLIBCXX_USE_DEPRECATED
1230 : #pragma GCC diagnostic push
1231 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
1232 : // Postcondition: use_count() == 1 and __r.get() == 0
1233 : template<typename _Yp, typename = _Compatible<_Yp>>
1234 : __shared_ptr(auto_ptr<_Yp>&& __r);
1235 : #pragma GCC diagnostic pop
1236 : #endif
1237 :
1238 : constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { }
1239 :
1240 : template<typename _Yp>
1241 : _Assignable<_Yp>
1242 : operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1243 : {
1244 : _M_ptr = __r._M_ptr;
1245 : _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
1246 : return *this;
1247 : }
1248 :
1249 : #if _GLIBCXX_USE_DEPRECATED
1250 : #pragma GCC diagnostic push
1251 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
1252 : template<typename _Yp>
1253 : _Assignable<_Yp>
1254 : operator=(auto_ptr<_Yp>&& __r)
1255 : {
1256 : __shared_ptr(std::move(__r)).swap(*this);
1257 : return *this;
1258 : }
1259 : #pragma GCC diagnostic pop
1260 : #endif
1261 :
1262 : __shared_ptr&
1263 : operator=(__shared_ptr&& __r) noexcept
1264 : {
1265 : __shared_ptr(std::move(__r)).swap(*this);
1266 : return *this;
1267 : }
1268 :
1269 : template<class _Yp>
1270 : _Assignable<_Yp>
1271 : operator=(__shared_ptr<_Yp, _Lp>&& __r) noexcept
1272 : {
1273 : __shared_ptr(std::move(__r)).swap(*this);
1274 : return *this;
1275 : }
1276 :
1277 : template<typename _Yp, typename _Del>
1278 : _UniqAssignable<_Yp, _Del>
1279 : operator=(unique_ptr<_Yp, _Del>&& __r)
1280 : {
1281 : __shared_ptr(std::move(__r)).swap(*this);
1282 : return *this;
1283 : }
1284 :
1285 : void
1286 : reset() noexcept
1287 : { __shared_ptr().swap(*this); }
1288 :
1289 : template<typename _Yp>
1290 : _SafeConv<_Yp>
1291 : reset(_Yp* __p) // _Yp must be complete.
1292 : {
1293 : // Catch self-reset errors.
1294 : __glibcxx_assert(__p == 0 || __p != _M_ptr);
1295 : __shared_ptr(__p).swap(*this);
1296 : }
1297 :
1298 : template<typename _Yp, typename _Deleter>
1299 : _SafeConv<_Yp>
1300 : reset(_Yp* __p, _Deleter __d)
1301 : { __shared_ptr(__p, std::move(__d)).swap(*this); }
1302 :
1303 : template<typename _Yp, typename _Deleter, typename _Alloc>
1304 : _SafeConv<_Yp>
1305 : reset(_Yp* __p, _Deleter __d, _Alloc __a)
1306 : { __shared_ptr(__p, std::move(__d), std::move(__a)).swap(*this); }
1307 :
1308 : element_type*
1309 14325 : get() const noexcept
1310 : { return _M_ptr; }
1311 :
1312 955 : explicit operator bool() const // never throws
1313 : { return _M_ptr == 0 ? false : true; }
1314 :
1315 : bool
1316 : unique() const noexcept
1317 : { return _M_refcount._M_unique(); }
1318 :
1319 : long
1320 : use_count() const noexcept
1321 : { return _M_refcount._M_get_use_count(); }
1322 :
1323 : void
1324 : swap(__shared_ptr<_Tp, _Lp>& __other) noexcept
1325 : {
1326 : std::swap(_M_ptr, __other._M_ptr);
1327 : _M_refcount._M_swap(__other._M_refcount);
1328 : }
1329 :
1330 : template<typename _Tp1>
1331 : bool
1332 : owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const noexcept
1333 : { return _M_refcount._M_less(__rhs._M_refcount); }
1334 :
1335 : template<typename _Tp1>
1336 : bool
1337 : owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const noexcept
1338 : { return _M_refcount._M_less(__rhs._M_refcount); }
1339 :
1340 : protected:
1341 : // This constructor is non-standard, it is used by allocate_shared.
1342 : template<typename _Alloc, typename... _Args>
1343 955 : __shared_ptr(_Sp_alloc_shared_tag<_Alloc> __tag, _Args&&... __args)
1344 955 : : _M_ptr(), _M_refcount(_M_ptr, __tag, std::forward<_Args>(__args)...)
1345 955 : { _M_enable_shared_from_this_with(_M_ptr); }
1346 :
1347 : template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
1348 : typename... _Args>
1349 : friend __shared_ptr<_Tp1, _Lp1>
1350 : __allocate_shared(const _Alloc& __a, _Args&&... __args);
1351 :
1352 : // This constructor is used by __weak_ptr::lock() and
1353 : // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t).
1354 : __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t)
1355 : : _M_refcount(__r._M_refcount, std::nothrow)
1356 : {
1357 : _M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr;
1358 : }
1359 :
1360 : friend class __weak_ptr<_Tp, _Lp>;
1361 :
1362 : private:
1363 :
1364 : template<typename _Yp>
1365 : using __esft_base_t = decltype(__enable_shared_from_this_base(
1366 : std::declval<const __shared_count<_Lp>&>(),
1367 : std::declval<_Yp*>()));
1368 :
1369 : // Detect an accessible and unambiguous enable_shared_from_this base.
1370 : template<typename _Yp, typename = void>
1371 : struct __has_esft_base
1372 : : false_type { };
1373 :
1374 : template<typename _Yp>
1375 : struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>>
1376 : : __not_<is_array<_Tp>> { }; // No enable shared_from_this for arrays
1377 :
1378 : template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
1379 : typename enable_if<__has_esft_base<_Yp2>::value>::type
1380 : _M_enable_shared_from_this_with(_Yp* __p) noexcept
1381 : {
1382 : if (auto __base = __enable_shared_from_this_base(_M_refcount, __p))
1383 : __base->_M_weak_assign(const_cast<_Yp2*>(__p), _M_refcount);
1384 : }
1385 :
1386 : template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
1387 : typename enable_if<!__has_esft_base<_Yp2>::value>::type
1388 955 : _M_enable_shared_from_this_with(_Yp*) noexcept
1389 : { }
1390 :
1391 : void*
1392 : _M_get_deleter(const std::type_info& __ti) const noexcept
1393 : { return _M_refcount._M_get_deleter(__ti); }
1394 :
1395 : template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1396 : template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1397 :
1398 : template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
1399 : friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&) noexcept;
1400 :
1401 : template<typename _Del, typename _Tp1>
1402 : friend _Del* get_deleter(const shared_ptr<_Tp1>&) noexcept;
1403 :
1404 : element_type* _M_ptr; // Contained pointer.
1405 : __shared_count<_Lp> _M_refcount; // Reference counter.
1406 : };
1407 :
1408 :
1409 : // 20.7.2.2.7 shared_ptr comparisons
1410 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1411 : inline bool
1412 : operator==(const __shared_ptr<_Tp1, _Lp>& __a,
1413 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1414 : { return __a.get() == __b.get(); }
1415 :
1416 : template<typename _Tp, _Lock_policy _Lp>
1417 : inline bool
1418 : operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1419 : { return !__a; }
1420 :
1421 : template<typename _Tp, _Lock_policy _Lp>
1422 : inline bool
1423 : operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1424 : { return !__a; }
1425 :
1426 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1427 : inline bool
1428 : operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
1429 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1430 : { return __a.get() != __b.get(); }
1431 :
1432 : template<typename _Tp, _Lock_policy _Lp>
1433 : inline bool
1434 : operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1435 : { return (bool)__a; }
1436 :
1437 : template<typename _Tp, _Lock_policy _Lp>
1438 : inline bool
1439 : operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1440 : { return (bool)__a; }
1441 :
1442 : template<typename _Tp, typename _Up, _Lock_policy _Lp>
1443 : inline bool
1444 : operator<(const __shared_ptr<_Tp, _Lp>& __a,
1445 : const __shared_ptr<_Up, _Lp>& __b) noexcept
1446 : {
1447 : using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1448 : using _Up_elt = typename __shared_ptr<_Up, _Lp>::element_type;
1449 : using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type;
1450 : return less<_Vp>()(__a.get(), __b.get());
1451 : }
1452 :
1453 : template<typename _Tp, _Lock_policy _Lp>
1454 : inline bool
1455 : operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1456 : {
1457 : using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1458 : return less<_Tp_elt*>()(__a.get(), nullptr);
1459 : }
1460 :
1461 : template<typename _Tp, _Lock_policy _Lp>
1462 : inline bool
1463 : operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1464 : {
1465 : using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1466 : return less<_Tp_elt*>()(nullptr, __a.get());
1467 : }
1468 :
1469 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1470 : inline bool
1471 : operator<=(const __shared_ptr<_Tp1, _Lp>& __a,
1472 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1473 : { return !(__b < __a); }
1474 :
1475 : template<typename _Tp, _Lock_policy _Lp>
1476 : inline bool
1477 : operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1478 : { return !(nullptr < __a); }
1479 :
1480 : template<typename _Tp, _Lock_policy _Lp>
1481 : inline bool
1482 : operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1483 : { return !(__a < nullptr); }
1484 :
1485 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1486 : inline bool
1487 : operator>(const __shared_ptr<_Tp1, _Lp>& __a,
1488 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1489 : { return (__b < __a); }
1490 :
1491 : template<typename _Tp, _Lock_policy _Lp>
1492 : inline bool
1493 : operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1494 : { return nullptr < __a; }
1495 :
1496 : template<typename _Tp, _Lock_policy _Lp>
1497 : inline bool
1498 : operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1499 : { return __a < nullptr; }
1500 :
1501 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1502 : inline bool
1503 : operator>=(const __shared_ptr<_Tp1, _Lp>& __a,
1504 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1505 : { return !(__a < __b); }
1506 :
1507 : template<typename _Tp, _Lock_policy _Lp>
1508 : inline bool
1509 : operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1510 : { return !(__a < nullptr); }
1511 :
1512 : template<typename _Tp, _Lock_policy _Lp>
1513 : inline bool
1514 : operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1515 : { return !(nullptr < __a); }
1516 :
1517 : // 20.7.2.2.8 shared_ptr specialized algorithms.
1518 : template<typename _Tp, _Lock_policy _Lp>
1519 : inline void
1520 : swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept
1521 : { __a.swap(__b); }
1522 :
1523 : // 20.7.2.2.9 shared_ptr casts
1524 :
1525 : // The seemingly equivalent code:
1526 : // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
1527 : // will eventually result in undefined behaviour, attempting to
1528 : // delete the same object twice.
1529 : /// static_pointer_cast
1530 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1531 : inline __shared_ptr<_Tp, _Lp>
1532 : static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1533 : {
1534 : using _Sp = __shared_ptr<_Tp, _Lp>;
1535 : return _Sp(__r, static_cast<typename _Sp::element_type*>(__r.get()));
1536 : }
1537 :
1538 : // The seemingly equivalent code:
1539 : // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
1540 : // will eventually result in undefined behaviour, attempting to
1541 : // delete the same object twice.
1542 : /// const_pointer_cast
1543 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1544 : inline __shared_ptr<_Tp, _Lp>
1545 : const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1546 : {
1547 : using _Sp = __shared_ptr<_Tp, _Lp>;
1548 : return _Sp(__r, const_cast<typename _Sp::element_type*>(__r.get()));
1549 : }
1550 :
1551 : // The seemingly equivalent code:
1552 : // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
1553 : // will eventually result in undefined behaviour, attempting to
1554 : // delete the same object twice.
1555 : /// dynamic_pointer_cast
1556 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1557 : inline __shared_ptr<_Tp, _Lp>
1558 : dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1559 : {
1560 : using _Sp = __shared_ptr<_Tp, _Lp>;
1561 : if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
1562 : return _Sp(__r, __p);
1563 : return _Sp();
1564 : }
1565 :
1566 : #if __cplusplus > 201402L
1567 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1568 : inline __shared_ptr<_Tp, _Lp>
1569 : reinterpret_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1570 : {
1571 : using _Sp = __shared_ptr<_Tp, _Lp>;
1572 : return _Sp(__r, reinterpret_cast<typename _Sp::element_type*>(__r.get()));
1573 : }
1574 : #endif
1575 :
1576 : template<typename _Tp, _Lock_policy _Lp>
1577 : class __weak_ptr
1578 : {
1579 : template<typename _Yp, typename _Res = void>
1580 : using _Compatible = typename
1581 : enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
1582 :
1583 : // Constraint for assignment from shared_ptr and weak_ptr:
1584 : template<typename _Yp>
1585 : using _Assignable = _Compatible<_Yp, __weak_ptr&>;
1586 :
1587 : public:
1588 : using element_type = typename remove_extent<_Tp>::type;
1589 :
1590 : constexpr __weak_ptr() noexcept
1591 : : _M_ptr(nullptr), _M_refcount()
1592 : { }
1593 :
1594 : __weak_ptr(const __weak_ptr&) noexcept = default;
1595 :
1596 : ~__weak_ptr() = default;
1597 :
1598 : // The "obvious" converting constructor implementation:
1599 : //
1600 : // template<typename _Tp1>
1601 : // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
1602 : // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
1603 : // { }
1604 : //
1605 : // has a serious problem.
1606 : //
1607 : // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
1608 : // conversion may require access to *__r._M_ptr (virtual inheritance).
1609 : //
1610 : // It is not possible to avoid spurious access violations since
1611 : // in multithreaded programs __r._M_ptr may be invalidated at any point.
1612 : template<typename _Yp, typename = _Compatible<_Yp>>
1613 : __weak_ptr(const __weak_ptr<_Yp, _Lp>& __r) noexcept
1614 : : _M_refcount(__r._M_refcount)
1615 : { _M_ptr = __r.lock().get(); }
1616 :
1617 : template<typename _Yp, typename = _Compatible<_Yp>>
1618 : __weak_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1619 : : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1620 : { }
1621 :
1622 : __weak_ptr(__weak_ptr&& __r) noexcept
1623 : : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount))
1624 : { __r._M_ptr = nullptr; }
1625 :
1626 : template<typename _Yp, typename = _Compatible<_Yp>>
1627 : __weak_ptr(__weak_ptr<_Yp, _Lp>&& __r) noexcept
1628 : : _M_ptr(__r.lock().get()), _M_refcount(std::move(__r._M_refcount))
1629 : { __r._M_ptr = nullptr; }
1630 :
1631 : __weak_ptr&
1632 : operator=(const __weak_ptr& __r) noexcept = default;
1633 :
1634 : template<typename _Yp>
1635 : _Assignable<_Yp>
1636 : operator=(const __weak_ptr<_Yp, _Lp>& __r) noexcept
1637 : {
1638 : _M_ptr = __r.lock().get();
1639 : _M_refcount = __r._M_refcount;
1640 : return *this;
1641 : }
1642 :
1643 : template<typename _Yp>
1644 : _Assignable<_Yp>
1645 : operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1646 : {
1647 : _M_ptr = __r._M_ptr;
1648 : _M_refcount = __r._M_refcount;
1649 : return *this;
1650 : }
1651 :
1652 : __weak_ptr&
1653 : operator=(__weak_ptr&& __r) noexcept
1654 : {
1655 : _M_ptr = __r._M_ptr;
1656 : _M_refcount = std::move(__r._M_refcount);
1657 : __r._M_ptr = nullptr;
1658 : return *this;
1659 : }
1660 :
1661 : template<typename _Yp>
1662 : _Assignable<_Yp>
1663 : operator=(__weak_ptr<_Yp, _Lp>&& __r) noexcept
1664 : {
1665 : _M_ptr = __r.lock().get();
1666 : _M_refcount = std::move(__r._M_refcount);
1667 : __r._M_ptr = nullptr;
1668 : return *this;
1669 : }
1670 :
1671 : __shared_ptr<_Tp, _Lp>
1672 : lock() const noexcept
1673 : { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); }
1674 :
1675 : long
1676 : use_count() const noexcept
1677 : { return _M_refcount._M_get_use_count(); }
1678 :
1679 : bool
1680 : expired() const noexcept
1681 : { return _M_refcount._M_get_use_count() == 0; }
1682 :
1683 : template<typename _Tp1>
1684 : bool
1685 : owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const noexcept
1686 : { return _M_refcount._M_less(__rhs._M_refcount); }
1687 :
1688 : template<typename _Tp1>
1689 : bool
1690 : owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const noexcept
1691 : { return _M_refcount._M_less(__rhs._M_refcount); }
1692 :
1693 : void
1694 : reset() noexcept
1695 : { __weak_ptr().swap(*this); }
1696 :
1697 : void
1698 : swap(__weak_ptr& __s) noexcept
1699 : {
1700 : std::swap(_M_ptr, __s._M_ptr);
1701 : _M_refcount._M_swap(__s._M_refcount);
1702 : }
1703 :
1704 : private:
1705 : // Used by __enable_shared_from_this.
1706 : void
1707 : _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept
1708 : {
1709 : if (use_count() == 0)
1710 : {
1711 : _M_ptr = __ptr;
1712 : _M_refcount = __refcount;
1713 : }
1714 : }
1715 :
1716 : template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1717 : template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1718 : friend class __enable_shared_from_this<_Tp, _Lp>;
1719 : friend class enable_shared_from_this<_Tp>;
1720 :
1721 : element_type* _M_ptr; // Contained pointer.
1722 : __weak_count<_Lp> _M_refcount; // Reference counter.
1723 : };
1724 :
1725 : // 20.7.2.3.6 weak_ptr specialized algorithms.
1726 : template<typename _Tp, _Lock_policy _Lp>
1727 : inline void
1728 : swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept
1729 : { __a.swap(__b); }
1730 :
1731 : template<typename _Tp, typename _Tp1>
1732 : struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool>
1733 : {
1734 : bool
1735 : operator()(const _Tp& __lhs, const _Tp& __rhs) const noexcept
1736 : { return __lhs.owner_before(__rhs); }
1737 :
1738 : bool
1739 : operator()(const _Tp& __lhs, const _Tp1& __rhs) const noexcept
1740 : { return __lhs.owner_before(__rhs); }
1741 :
1742 : bool
1743 : operator()(const _Tp1& __lhs, const _Tp& __rhs) const noexcept
1744 : { return __lhs.owner_before(__rhs); }
1745 : };
1746 :
1747 : template<>
1748 : struct _Sp_owner_less<void, void>
1749 : {
1750 : template<typename _Tp, typename _Up>
1751 : auto
1752 : operator()(const _Tp& __lhs, const _Up& __rhs) const noexcept
1753 : -> decltype(__lhs.owner_before(__rhs))
1754 : { return __lhs.owner_before(__rhs); }
1755 :
1756 : using is_transparent = void;
1757 : };
1758 :
1759 : template<typename _Tp, _Lock_policy _Lp>
1760 : struct owner_less<__shared_ptr<_Tp, _Lp>>
1761 : : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>
1762 : { };
1763 :
1764 : template<typename _Tp, _Lock_policy _Lp>
1765 : struct owner_less<__weak_ptr<_Tp, _Lp>>
1766 : : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>>
1767 : { };
1768 :
1769 :
1770 : template<typename _Tp, _Lock_policy _Lp>
1771 : class __enable_shared_from_this
1772 : {
1773 : protected:
1774 : constexpr __enable_shared_from_this() noexcept { }
1775 :
1776 : __enable_shared_from_this(const __enable_shared_from_this&) noexcept { }
1777 :
1778 : __enable_shared_from_this&
1779 : operator=(const __enable_shared_from_this&) noexcept
1780 : { return *this; }
1781 :
1782 : ~__enable_shared_from_this() { }
1783 :
1784 : public:
1785 : __shared_ptr<_Tp, _Lp>
1786 : shared_from_this()
1787 : { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
1788 :
1789 : __shared_ptr<const _Tp, _Lp>
1790 : shared_from_this() const
1791 : { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
1792 :
1793 : #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
1794 : __weak_ptr<_Tp, _Lp>
1795 : weak_from_this() noexcept
1796 : { return this->_M_weak_this; }
1797 :
1798 : __weak_ptr<const _Tp, _Lp>
1799 : weak_from_this() const noexcept
1800 : { return this->_M_weak_this; }
1801 : #endif
1802 :
1803 : private:
1804 : template<typename _Tp1>
1805 : void
1806 : _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept
1807 : { _M_weak_this._M_assign(__p, __n); }
1808 :
1809 : friend const __enable_shared_from_this*
1810 : __enable_shared_from_this_base(const __shared_count<_Lp>&,
1811 : const __enable_shared_from_this* __p)
1812 : { return __p; }
1813 :
1814 : template<typename, _Lock_policy>
1815 : friend class __shared_ptr;
1816 :
1817 : mutable __weak_ptr<_Tp, _Lp> _M_weak_this;
1818 : };
1819 :
1820 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy,
1821 : typename _Alloc, typename... _Args>
1822 : inline __shared_ptr<_Tp, _Lp>
1823 : __allocate_shared(const _Alloc& __a, _Args&&... __args)
1824 : {
1825 : return __shared_ptr<_Tp, _Lp>(_Sp_alloc_shared_tag<_Alloc>{__a},
1826 : std::forward<_Args>(__args)...);
1827 : }
1828 :
1829 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy,
1830 : typename... _Args>
1831 : inline __shared_ptr<_Tp, _Lp>
1832 : __make_shared(_Args&&... __args)
1833 : {
1834 : typedef typename std::remove_const<_Tp>::type _Tp_nc;
1835 : return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
1836 : std::forward<_Args>(__args)...);
1837 : }
1838 :
1839 : /// std::hash specialization for __shared_ptr.
1840 : template<typename _Tp, _Lock_policy _Lp>
1841 : struct hash<__shared_ptr<_Tp, _Lp>>
1842 : : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>>
1843 : {
1844 : size_t
1845 : operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept
1846 : {
1847 : return hash<typename __shared_ptr<_Tp, _Lp>::element_type*>()(
1848 : __s.get());
1849 : }
1850 : };
1851 :
1852 : _GLIBCXX_END_NAMESPACE_VERSION
1853 : } // namespace
1854 :
1855 : #endif // _SHARED_PTR_BASE_H
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