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1 : // shared_ptr and weak_ptr implementation details -*- C++ -*-
2 :
3 : // Copyright (C) 2007-2018 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 1460 : _Sp_counted_base() noexcept
118 1460 : : _M_use_count(1), _M_weak_count(1) { }
119 :
120 : virtual
121 1460 : ~_Sp_counted_base() noexcept
122 1460 : { }
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 1410 : _M_add_ref_copy()
139 1410 : { __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 3506 : _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 3506 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
153 : {
154 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
155 1460 : _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 1460 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count,
168 1460 : -1) == 1)
169 : {
170 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
171 1442 : _M_destroy();
172 : }
173 : }
174 3506 : }
175 :
176 : void
177 167 : _M_weak_add_ref() noexcept
178 167 : { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); }
179 :
180 : void
181 167 : _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);
185 167 : 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 18 : _M_destroy();
195 : }
196 167 : }
197 :
198 : long
199 1522 : _M_get_use_count() const noexcept
200 : {
201 : // No memory barrier is used here so there is no synchronization
202 : // with other threads.
203 1522 : 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
283 636 : _Sp_counted_base<_S_atomic>::
284 : _M_add_ref_lock_nothrow()
285 : {
286 : // Perform lock-free add-if-not-zero operation.
287 636 : _Atomic_word __count = _M_get_use_count();
288 0 : do
289 : {
290 636 : if (__count == 0)
291 0 : return false;
292 : // Replace the current counter value with the old value + 1, as
293 : // long as it's not changed meanwhile.
294 : }
295 636 : while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
296 : true, __ATOMIC_ACQ_REL,
297 : __ATOMIC_RELAXED));
298 636 : 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 : _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 : struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp
413 : {
414 1460 : 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 2920 : _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 : alignas(type_info) static constexpr char __tag[sizeof(type_info)] = { };
511 0 : return reinterpret_cast<const type_info&>(__tag);
512 : }
513 : };
514 :
515 : template<typename _Alloc>
516 : struct _Sp_alloc_shared_tag
517 : {
518 : const _Alloc& _M_a;
519 : };
520 :
521 : template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
522 : class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp>
523 : {
524 : class _Impl : _Sp_ebo_helper<0, _Alloc>
525 : {
526 : typedef _Sp_ebo_helper<0, _Alloc> _A_base;
527 :
528 : public:
529 1460 : explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { }
530 :
531 2920 : _Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); }
532 :
533 : __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
534 : };
535 :
536 : public:
537 : using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
538 :
539 : template<typename... _Args>
540 1460 : _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
541 1460 : : _M_impl(__a)
542 : {
543 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
544 : // 2070. allocate_shared should use allocator_traits<A>::construct
545 1460 : allocator_traits<_Alloc>::construct(__a, _M_ptr(),
546 : std::forward<_Args>(__args)...); // might throw
547 1460 : }
548 :
549 1460 : ~_Sp_counted_ptr_inplace() noexcept { }
550 :
551 : virtual void
552 1460 : _M_dispose() noexcept
553 : {
554 1460 : allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr());
555 1460 : }
556 :
557 : // Override because the allocator needs to know the dynamic type
558 : virtual void
559 1460 : _M_destroy() noexcept
560 : {
561 2920 : __allocator_type __a(_M_impl._M_alloc());
562 2920 : __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
563 1460 : this->~_Sp_counted_ptr_inplace();
564 1460 : }
565 :
566 : private:
567 : friend class __shared_count<_Lp>; // To be able to call _M_ptr().
568 :
569 : // No longer used, but code compiled against old libstdc++ headers
570 : // might still call it from __shared_ptr ctor to get the pointer out.
571 : virtual void*
572 0 : _M_get_deleter(const std::type_info& __ti) noexcept override
573 : {
574 : // Check for the fake type_info first, so we don't try to access it
575 : // as a real type_info object.
576 0 : if (&__ti == &_Sp_make_shared_tag::_S_ti())
577 0 : return const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
578 : #if __cpp_rtti
579 : // Callers compiled with old libstdc++ headers and RTTI enabled
580 : // might pass this instead:
581 0 : else if (__ti == typeid(_Sp_make_shared_tag))
582 0 : return const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
583 : #else
584 : // Cannot detect a real type_info object. If the linker keeps a
585 : // definition of this function compiled with -fno-rtti then callers
586 : // that have RTTI enabled and pass a real type_info object will get
587 : // a null pointer returned.
588 : #endif
589 0 : return nullptr;
590 : }
591 :
592 4380 : _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); }
593 :
594 : _Impl _M_impl;
595 : };
596 :
597 : // The default deleter for shared_ptr<T[]> and shared_ptr<T[N]>.
598 : struct __sp_array_delete
599 : {
600 : template<typename _Yp>
601 : void operator()(_Yp* __p) const { delete[] __p; }
602 : };
603 :
604 : template<_Lock_policy _Lp>
605 : class __shared_count
606 : {
607 : template<typename _Tp>
608 : struct __not_alloc_shared_tag { using type = void; };
609 :
610 : template<typename _Tp>
611 : struct __not_alloc_shared_tag<_Sp_alloc_shared_tag<_Tp>> { };
612 :
613 : public:
614 1101 : constexpr __shared_count() noexcept : _M_pi(0)
615 1101 : { }
616 :
617 : template<typename _Ptr>
618 : explicit
619 : __shared_count(_Ptr __p) : _M_pi(0)
620 : {
621 : __try
622 : {
623 : _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
624 : }
625 : __catch(...)
626 : {
627 : delete __p;
628 : __throw_exception_again;
629 : }
630 : }
631 :
632 : template<typename _Ptr>
633 : __shared_count(_Ptr __p, /* is_array = */ false_type)
634 : : __shared_count(__p)
635 : { }
636 :
637 : template<typename _Ptr>
638 : __shared_count(_Ptr __p, /* is_array = */ true_type)
639 : : __shared_count(__p, __sp_array_delete{}, allocator<void>())
640 : { }
641 :
642 : template<typename _Ptr, typename _Deleter,
643 : typename = typename __not_alloc_shared_tag<_Deleter>::type>
644 : __shared_count(_Ptr __p, _Deleter __d)
645 : : __shared_count(__p, std::move(__d), allocator<void>())
646 : { }
647 :
648 : template<typename _Ptr, typename _Deleter, typename _Alloc,
649 : typename = typename __not_alloc_shared_tag<_Deleter>::type>
650 : __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
651 : {
652 : typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
653 : __try
654 : {
655 : typename _Sp_cd_type::__allocator_type __a2(__a);
656 : auto __guard = std::__allocate_guarded(__a2);
657 : _Sp_cd_type* __mem = __guard.get();
658 : ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a));
659 : _M_pi = __mem;
660 : __guard = nullptr;
661 : }
662 : __catch(...)
663 : {
664 : __d(__p); // Call _Deleter on __p.
665 : __throw_exception_again;
666 : }
667 : }
668 :
669 : template<typename _Tp, typename _Alloc, typename... _Args>
670 1460 : __shared_count(_Tp*& __p, _Sp_alloc_shared_tag<_Alloc> __a,
671 : _Args&&... __args)
672 : {
673 : typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
674 2920 : typename _Sp_cp_type::__allocator_type __a2(__a._M_a);
675 1460 : auto __guard = std::__allocate_guarded(__a2);
676 1460 : _Sp_cp_type* __mem = __guard.get();
677 2269 : auto __pi = ::new (__mem)
678 809 : _Sp_cp_type(__a._M_a, std::forward<_Args>(__args)...);
679 1460 : __guard = nullptr;
680 1460 : _M_pi = __pi;
681 1460 : __p = __pi->_M_ptr();
682 1460 : }
683 :
684 : #if _GLIBCXX_USE_DEPRECATED
685 : #pragma GCC diagnostic push
686 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
687 : // Special case for auto_ptr<_Tp> to provide the strong guarantee.
688 : template<typename _Tp>
689 : explicit
690 : __shared_count(std::auto_ptr<_Tp>&& __r);
691 : #pragma GCC diagnostic pop
692 : #endif
693 :
694 : // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
695 : template<typename _Tp, typename _Del>
696 : explicit
697 : __shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0)
698 : {
699 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
700 : // 2415. Inconsistency between unique_ptr and shared_ptr
701 : if (__r.get() == nullptr)
702 : return;
703 :
704 : using _Ptr = typename unique_ptr<_Tp, _Del>::pointer;
705 : using _Del2 = typename conditional<is_reference<_Del>::value,
706 : reference_wrapper<typename remove_reference<_Del>::type>,
707 : _Del>::type;
708 : using _Sp_cd_type
709 : = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>;
710 : using _Alloc = allocator<_Sp_cd_type>;
711 : using _Alloc_traits = allocator_traits<_Alloc>;
712 : _Alloc __a;
713 : _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1);
714 : _Alloc_traits::construct(__a, __mem, __r.release(),
715 : __r.get_deleter()); // non-throwing
716 : _M_pi = __mem;
717 : }
718 :
719 : // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
720 : explicit __shared_count(const __weak_count<_Lp>& __r);
721 :
722 : // Does not throw if __r._M_get_use_count() == 0, caller must check.
723 : explicit __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t);
724 :
725 4255 : ~__shared_count() noexcept
726 : {
727 4255 : if (_M_pi != nullptr)
728 3201 : _M_pi->_M_release();
729 4255 : }
730 :
731 700 : __shared_count(const __shared_count& __r) noexcept
732 700 : : _M_pi(__r._M_pi)
733 : {
734 700 : if (_M_pi != 0)
735 700 : _M_pi->_M_add_ref_copy();
736 700 : }
737 :
738 : __shared_count&
739 724 : operator=(const __shared_count& __r) noexcept
740 : {
741 724 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
742 724 : if (__tmp != _M_pi)
743 : {
744 710 : if (__tmp != 0)
745 710 : __tmp->_M_add_ref_copy();
746 710 : if (_M_pi != 0)
747 305 : _M_pi->_M_release();
748 710 : _M_pi = __tmp;
749 : }
750 724 : return *this;
751 : }
752 :
753 : void
754 1054 : _M_swap(__shared_count& __r) noexcept
755 : {
756 1054 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
757 1054 : __r._M_pi = _M_pi;
758 1054 : _M_pi = __tmp;
759 1054 : }
760 :
761 : long
762 886 : _M_get_use_count() const noexcept
763 886 : { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
764 :
765 : bool
766 83 : _M_unique() const noexcept
767 83 : { return this->_M_get_use_count() == 1; }
768 :
769 : void*
770 : _M_get_deleter(const std::type_info& __ti) const noexcept
771 : { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; }
772 :
773 : bool
774 : _M_less(const __shared_count& __rhs) const noexcept
775 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
776 :
777 : bool
778 : _M_less(const __weak_count<_Lp>& __rhs) const noexcept
779 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
780 :
781 : // Friend function injected into enclosing namespace and found by ADL
782 : friend inline bool
783 : operator==(const __shared_count& __a, const __shared_count& __b) noexcept
784 : { return __a._M_pi == __b._M_pi; }
785 :
786 : private:
787 : friend class __weak_count<_Lp>;
788 :
789 : _Sp_counted_base<_Lp>* _M_pi;
790 : };
791 :
792 :
793 : template<_Lock_policy _Lp>
794 : class __weak_count
795 : {
796 : public:
797 : constexpr __weak_count() noexcept : _M_pi(nullptr)
798 : { }
799 :
800 167 : __weak_count(const __shared_count<_Lp>& __r) noexcept
801 167 : : _M_pi(__r._M_pi)
802 : {
803 167 : if (_M_pi != nullptr)
804 167 : _M_pi->_M_weak_add_ref();
805 167 : }
806 :
807 : __weak_count(const __weak_count& __r) noexcept
808 : : _M_pi(__r._M_pi)
809 : {
810 : if (_M_pi != nullptr)
811 : _M_pi->_M_weak_add_ref();
812 : }
813 :
814 256 : __weak_count(__weak_count&& __r) noexcept
815 256 : : _M_pi(__r._M_pi)
816 256 : { __r._M_pi = nullptr; }
817 :
818 423 : ~__weak_count() noexcept
819 : {
820 423 : if (_M_pi != nullptr)
821 167 : _M_pi->_M_weak_release();
822 423 : }
823 :
824 : __weak_count&
825 : operator=(const __shared_count<_Lp>& __r) noexcept
826 : {
827 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
828 : if (__tmp != nullptr)
829 : __tmp->_M_weak_add_ref();
830 : if (_M_pi != nullptr)
831 : _M_pi->_M_weak_release();
832 : _M_pi = __tmp;
833 : return *this;
834 : }
835 :
836 : __weak_count&
837 : operator=(const __weak_count& __r) noexcept
838 : {
839 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
840 : if (__tmp != nullptr)
841 : __tmp->_M_weak_add_ref();
842 : if (_M_pi != nullptr)
843 : _M_pi->_M_weak_release();
844 : _M_pi = __tmp;
845 : return *this;
846 : }
847 :
848 : __weak_count&
849 92 : operator=(__weak_count&& __r) noexcept
850 : {
851 92 : if (_M_pi != nullptr)
852 0 : _M_pi->_M_weak_release();
853 92 : _M_pi = __r._M_pi;
854 92 : __r._M_pi = nullptr;
855 92 : return *this;
856 : }
857 :
858 : void
859 0 : _M_swap(__weak_count& __r) noexcept
860 : {
861 0 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
862 0 : __r._M_pi = _M_pi;
863 0 : _M_pi = __tmp;
864 0 : }
865 :
866 : long
867 : _M_get_use_count() const noexcept
868 : { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; }
869 :
870 : bool
871 : _M_less(const __weak_count& __rhs) const noexcept
872 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
873 :
874 : bool
875 : _M_less(const __shared_count<_Lp>& __rhs) const noexcept
876 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
877 :
878 : // Friend function injected into enclosing namespace and found by ADL
879 : friend inline bool
880 : operator==(const __weak_count& __a, const __weak_count& __b) noexcept
881 : { return __a._M_pi == __b._M_pi; }
882 :
883 : private:
884 : friend class __shared_count<_Lp>;
885 :
886 : _Sp_counted_base<_Lp>* _M_pi;
887 : };
888 :
889 : // Now that __weak_count is defined we can define this constructor:
890 : template<_Lock_policy _Lp>
891 : inline
892 : __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r)
893 : : _M_pi(__r._M_pi)
894 : {
895 : if (_M_pi != nullptr)
896 : _M_pi->_M_add_ref_lock();
897 : else
898 : __throw_bad_weak_ptr();
899 : }
900 :
901 : // Now that __weak_count is defined we can define this constructor:
902 : template<_Lock_policy _Lp>
903 : inline
904 636 : __shared_count<_Lp>::
905 : __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t)
906 636 : : _M_pi(__r._M_pi)
907 : {
908 636 : if (_M_pi != nullptr)
909 636 : if (!_M_pi->_M_add_ref_lock_nothrow())
910 0 : _M_pi = nullptr;
911 636 : }
912 :
913 : #define __cpp_lib_shared_ptr_arrays 201603
914 :
915 : // Helper traits for shared_ptr of array:
916 :
917 : // A pointer type Y* is said to be compatible with a pointer type T* when
918 : // either Y* is convertible to T* or Y is U[N] and T is U cv [].
919 : template<typename _Yp_ptr, typename _Tp_ptr>
920 : struct __sp_compatible_with
921 : : false_type
922 : { };
923 :
924 : template<typename _Yp, typename _Tp>
925 : struct __sp_compatible_with<_Yp*, _Tp*>
926 : : is_convertible<_Yp*, _Tp*>::type
927 : { };
928 :
929 : template<typename _Up, size_t _Nm>
930 : struct __sp_compatible_with<_Up(*)[_Nm], _Up(*)[]>
931 : : true_type
932 : { };
933 :
934 : template<typename _Up, size_t _Nm>
935 : struct __sp_compatible_with<_Up(*)[_Nm], const _Up(*)[]>
936 : : true_type
937 : { };
938 :
939 : template<typename _Up, size_t _Nm>
940 : struct __sp_compatible_with<_Up(*)[_Nm], volatile _Up(*)[]>
941 : : true_type
942 : { };
943 :
944 : template<typename _Up, size_t _Nm>
945 : struct __sp_compatible_with<_Up(*)[_Nm], const volatile _Up(*)[]>
946 : : true_type
947 : { };
948 :
949 : // Test conversion from Y(*)[N] to U(*)[N] without forming invalid type Y[N].
950 : template<typename _Up, size_t _Nm, typename _Yp, typename = void>
951 : struct __sp_is_constructible_arrN
952 : : false_type
953 : { };
954 :
955 : template<typename _Up, size_t _Nm, typename _Yp>
956 : struct __sp_is_constructible_arrN<_Up, _Nm, _Yp, __void_t<_Yp[_Nm]>>
957 : : is_convertible<_Yp(*)[_Nm], _Up(*)[_Nm]>::type
958 : { };
959 :
960 : // Test conversion from Y(*)[] to U(*)[] without forming invalid type Y[].
961 : template<typename _Up, typename _Yp, typename = void>
962 : struct __sp_is_constructible_arr
963 : : false_type
964 : { };
965 :
966 : template<typename _Up, typename _Yp>
967 : struct __sp_is_constructible_arr<_Up, _Yp, __void_t<_Yp[]>>
968 : : is_convertible<_Yp(*)[], _Up(*)[]>::type
969 : { };
970 :
971 : // Trait to check if shared_ptr<T> can be constructed from Y*.
972 : template<typename _Tp, typename _Yp>
973 : struct __sp_is_constructible;
974 :
975 : // When T is U[N], Y(*)[N] shall be convertible to T*;
976 : template<typename _Up, size_t _Nm, typename _Yp>
977 : struct __sp_is_constructible<_Up[_Nm], _Yp>
978 : : __sp_is_constructible_arrN<_Up, _Nm, _Yp>::type
979 : { };
980 :
981 : // when T is U[], Y(*)[] shall be convertible to T*;
982 : template<typename _Up, typename _Yp>
983 : struct __sp_is_constructible<_Up[], _Yp>
984 : : __sp_is_constructible_arr<_Up, _Yp>::type
985 : { };
986 :
987 : // otherwise, Y* shall be convertible to T*.
988 : template<typename _Tp, typename _Yp>
989 : struct __sp_is_constructible
990 : : is_convertible<_Yp*, _Tp*>::type
991 : { };
992 :
993 :
994 : // Define operator* and operator-> for shared_ptr<T>.
995 : template<typename _Tp, _Lock_policy _Lp,
996 : bool = is_array<_Tp>::value, bool = is_void<_Tp>::value>
997 : class __shared_ptr_access
998 : {
999 : public:
1000 : using element_type = _Tp;
1001 :
1002 : element_type&
1003 740 : operator*() const noexcept
1004 : {
1005 : __glibcxx_assert(_M_get() != nullptr);
1006 740 : return *_M_get();
1007 : }
1008 :
1009 : element_type*
1010 438 : operator->() const noexcept
1011 : {
1012 : _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
1013 438 : return _M_get();
1014 : }
1015 :
1016 : private:
1017 : element_type*
1018 1178 : _M_get() const noexcept
1019 1178 : { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
1020 : };
1021 :
1022 : // Define operator-> for shared_ptr<cv void>.
1023 : template<typename _Tp, _Lock_policy _Lp>
1024 : class __shared_ptr_access<_Tp, _Lp, false, true>
1025 : {
1026 : public:
1027 : using element_type = _Tp;
1028 :
1029 : element_type*
1030 : operator->() const noexcept
1031 : {
1032 : auto __ptr = static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get();
1033 : _GLIBCXX_DEBUG_PEDASSERT(__ptr != nullptr);
1034 : return __ptr;
1035 : }
1036 : };
1037 :
1038 : // Define operator[] for shared_ptr<T[]> and shared_ptr<T[N]>.
1039 : template<typename _Tp, _Lock_policy _Lp>
1040 : class __shared_ptr_access<_Tp, _Lp, true, false>
1041 : {
1042 : public:
1043 : using element_type = typename remove_extent<_Tp>::type;
1044 :
1045 : #if __cplusplus <= 201402L
1046 : [[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17")]]
1047 : element_type&
1048 : operator*() const noexcept
1049 : {
1050 : __glibcxx_assert(_M_get() != nullptr);
1051 : return *_M_get();
1052 : }
1053 :
1054 : [[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17")]]
1055 : element_type*
1056 : operator->() const noexcept
1057 : {
1058 : _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr);
1059 : return _M_get();
1060 : }
1061 : #endif
1062 :
1063 : element_type&
1064 : operator[](ptrdiff_t __i) const
1065 : {
1066 : __glibcxx_assert(_M_get() != nullptr);
1067 : __glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value);
1068 : return _M_get()[__i];
1069 : }
1070 :
1071 : private:
1072 : element_type*
1073 : _M_get() const noexcept
1074 : { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
1075 : };
1076 :
1077 : template<typename _Tp, _Lock_policy _Lp>
1078 724 : class __shared_ptr
1079 : : public __shared_ptr_access<_Tp, _Lp>
1080 : {
1081 : public:
1082 : using element_type = typename remove_extent<_Tp>::type;
1083 :
1084 : private:
1085 : // Constraint for taking ownership of a pointer of type _Yp*:
1086 : template<typename _Yp>
1087 : using _SafeConv
1088 : = typename enable_if<__sp_is_constructible<_Tp, _Yp>::value>::type;
1089 :
1090 : // Constraint for construction from shared_ptr and weak_ptr:
1091 : template<typename _Yp, typename _Res = void>
1092 : using _Compatible = typename
1093 : enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
1094 :
1095 : // Constraint for assignment from shared_ptr and weak_ptr:
1096 : template<typename _Yp>
1097 : using _Assignable = _Compatible<_Yp, __shared_ptr&>;
1098 :
1099 : // Constraint for construction from unique_ptr:
1100 : template<typename _Yp, typename _Del, typename _Res = void,
1101 : typename _Ptr = typename unique_ptr<_Yp, _Del>::pointer>
1102 : using _UniqCompatible = typename enable_if<__and_<
1103 : __sp_compatible_with<_Yp*, _Tp*>, is_convertible<_Ptr, element_type*>
1104 : >::value, _Res>::type;
1105 :
1106 : // Constraint for assignment from unique_ptr:
1107 : template<typename _Yp, typename _Del>
1108 : using _UniqAssignable = _UniqCompatible<_Yp, _Del, __shared_ptr&>;
1109 :
1110 : public:
1111 :
1112 : #if __cplusplus > 201402L
1113 : using weak_type = __weak_ptr<_Tp, _Lp>;
1114 : #endif
1115 :
1116 461 : constexpr __shared_ptr() noexcept
1117 461 : : _M_ptr(0), _M_refcount()
1118 461 : { }
1119 :
1120 : template<typename _Yp, typename = _SafeConv<_Yp>>
1121 : explicit
1122 : __shared_ptr(_Yp* __p)
1123 : : _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type())
1124 : {
1125 : static_assert( !is_void<_Yp>::value, "incomplete type" );
1126 : static_assert( sizeof(_Yp) > 0, "incomplete type" );
1127 : _M_enable_shared_from_this_with(__p);
1128 : }
1129 :
1130 : template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>>
1131 : __shared_ptr(_Yp* __p, _Deleter __d)
1132 : : _M_ptr(__p), _M_refcount(__p, std::move(__d))
1133 : {
1134 : static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
1135 : "deleter expression d(p) is well-formed");
1136 : _M_enable_shared_from_this_with(__p);
1137 : }
1138 :
1139 : template<typename _Yp, typename _Deleter, typename _Alloc,
1140 : typename = _SafeConv<_Yp>>
1141 : __shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a)
1142 : : _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a))
1143 : {
1144 : static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
1145 : "deleter expression d(p) is well-formed");
1146 : _M_enable_shared_from_this_with(__p);
1147 : }
1148 :
1149 : template<typename _Deleter>
1150 : __shared_ptr(nullptr_t __p, _Deleter __d)
1151 : : _M_ptr(0), _M_refcount(__p, std::move(__d))
1152 : { }
1153 :
1154 : template<typename _Deleter, typename _Alloc>
1155 : __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
1156 : : _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a))
1157 : { }
1158 :
1159 : template<typename _Yp>
1160 : __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r,
1161 : element_type* __p) noexcept
1162 : : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
1163 : { }
1164 :
1165 700 : __shared_ptr(const __shared_ptr&) noexcept = default;
1166 : __shared_ptr& operator=(const __shared_ptr&) noexcept = default;
1167 4255 : ~__shared_ptr() = default;
1168 :
1169 : template<typename _Yp, typename = _Compatible<_Yp>>
1170 : __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1171 : : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1172 : { }
1173 :
1174 358 : __shared_ptr(__shared_ptr&& __r) noexcept
1175 358 : : _M_ptr(__r._M_ptr), _M_refcount()
1176 : {
1177 358 : _M_refcount._M_swap(__r._M_refcount);
1178 358 : __r._M_ptr = 0;
1179 358 : }
1180 :
1181 : template<typename _Yp, typename = _Compatible<_Yp>>
1182 282 : __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r) noexcept
1183 282 : : _M_ptr(__r._M_ptr), _M_refcount()
1184 : {
1185 282 : _M_refcount._M_swap(__r._M_refcount);
1186 282 : __r._M_ptr = 0;
1187 282 : }
1188 :
1189 : template<typename _Yp, typename = _Compatible<_Yp>>
1190 : explicit __shared_ptr(const __weak_ptr<_Yp, _Lp>& __r)
1191 : : _M_refcount(__r._M_refcount) // may throw
1192 : {
1193 : // It is now safe to copy __r._M_ptr, as
1194 : // _M_refcount(__r._M_refcount) did not throw.
1195 : _M_ptr = __r._M_ptr;
1196 : }
1197 :
1198 : // If an exception is thrown this constructor has no effect.
1199 : template<typename _Yp, typename _Del,
1200 : typename = _UniqCompatible<_Yp, _Del>>
1201 : __shared_ptr(unique_ptr<_Yp, _Del>&& __r)
1202 : : _M_ptr(__r.get()), _M_refcount()
1203 : {
1204 : auto __raw = __to_address(__r.get());
1205 : _M_refcount = __shared_count<_Lp>(std::move(__r));
1206 : _M_enable_shared_from_this_with(__raw);
1207 : }
1208 :
1209 : #if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED
1210 : protected:
1211 : // If an exception is thrown this constructor has no effect.
1212 : template<typename _Tp1, typename _Del,
1213 : typename enable_if<__and_<
1214 : __not_<is_array<_Tp>>, is_array<_Tp1>,
1215 : is_convertible<typename unique_ptr<_Tp1, _Del>::pointer, _Tp*>
1216 : >::value, bool>::type = true>
1217 : __shared_ptr(unique_ptr<_Tp1, _Del>&& __r, __sp_array_delete)
1218 : : _M_ptr(__r.get()), _M_refcount()
1219 : {
1220 : auto __raw = __to_address(__r.get());
1221 : _M_refcount = __shared_count<_Lp>(std::move(__r));
1222 : _M_enable_shared_from_this_with(__raw);
1223 : }
1224 : public:
1225 : #endif
1226 :
1227 : #if _GLIBCXX_USE_DEPRECATED
1228 : #pragma GCC diagnostic push
1229 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
1230 : // Postcondition: use_count() == 1 and __r.get() == 0
1231 : template<typename _Yp, typename = _Compatible<_Yp>>
1232 : __shared_ptr(auto_ptr<_Yp>&& __r);
1233 : #pragma GCC diagnostic pop
1234 : #endif
1235 :
1236 : constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { }
1237 :
1238 : template<typename _Yp>
1239 : _Assignable<_Yp>
1240 : operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1241 : {
1242 : _M_ptr = __r._M_ptr;
1243 : _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
1244 : return *this;
1245 : }
1246 :
1247 : #if _GLIBCXX_USE_DEPRECATED
1248 : #pragma GCC diagnostic push
1249 : #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
1250 : template<typename _Yp>
1251 : _Assignable<_Yp>
1252 : operator=(auto_ptr<_Yp>&& __r)
1253 : {
1254 : __shared_ptr(std::move(__r)).swap(*this);
1255 : return *this;
1256 : }
1257 : #pragma GCC diagnostic pop
1258 : #endif
1259 :
1260 : __shared_ptr&
1261 358 : operator=(__shared_ptr&& __r) noexcept
1262 : {
1263 358 : __shared_ptr(std::move(__r)).swap(*this);
1264 358 : return *this;
1265 : }
1266 :
1267 : template<class _Yp>
1268 : _Assignable<_Yp>
1269 : operator=(__shared_ptr<_Yp, _Lp>&& __r) noexcept
1270 : {
1271 : __shared_ptr(std::move(__r)).swap(*this);
1272 : return *this;
1273 : }
1274 :
1275 : template<typename _Yp, typename _Del>
1276 : _UniqAssignable<_Yp, _Del>
1277 : operator=(unique_ptr<_Yp, _Del>&& __r)
1278 : {
1279 : __shared_ptr(std::move(__r)).swap(*this);
1280 : return *this;
1281 : }
1282 :
1283 : void
1284 56 : reset() noexcept
1285 56 : { __shared_ptr().swap(*this); }
1286 :
1287 : template<typename _Yp>
1288 : _SafeConv<_Yp>
1289 : reset(_Yp* __p) // _Yp must be complete.
1290 : {
1291 : // Catch self-reset errors.
1292 : __glibcxx_assert(__p == 0 || __p != _M_ptr);
1293 : __shared_ptr(__p).swap(*this);
1294 : }
1295 :
1296 : template<typename _Yp, typename _Deleter>
1297 : _SafeConv<_Yp>
1298 : reset(_Yp* __p, _Deleter __d)
1299 : { __shared_ptr(__p, std::move(__d)).swap(*this); }
1300 :
1301 : template<typename _Yp, typename _Deleter, typename _Alloc>
1302 : _SafeConv<_Yp>
1303 : reset(_Yp* __p, _Deleter __d, _Alloc __a)
1304 : { __shared_ptr(__p, std::move(__d), std::move(__a)).swap(*this); }
1305 :
1306 : element_type*
1307 1706 : get() const noexcept
1308 1706 : { return _M_ptr; }
1309 :
1310 438 : explicit operator bool() const // never throws
1311 438 : { return _M_ptr == 0 ? false : true; }
1312 :
1313 : bool
1314 83 : unique() const noexcept
1315 83 : { return _M_refcount._M_unique(); }
1316 :
1317 : long
1318 167 : use_count() const noexcept
1319 167 : { return _M_refcount._M_get_use_count(); }
1320 :
1321 : void
1322 414 : swap(__shared_ptr<_Tp, _Lp>& __other) noexcept
1323 : {
1324 414 : std::swap(_M_ptr, __other._M_ptr);
1325 414 : _M_refcount._M_swap(__other._M_refcount);
1326 414 : }
1327 :
1328 : template<typename _Tp1>
1329 : bool
1330 : owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const noexcept
1331 : { return _M_refcount._M_less(__rhs._M_refcount); }
1332 :
1333 : template<typename _Tp1>
1334 : bool
1335 : owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const noexcept
1336 : { return _M_refcount._M_less(__rhs._M_refcount); }
1337 :
1338 : protected:
1339 : // This constructor is non-standard, it is used by allocate_shared.
1340 : template<typename _Alloc, typename... _Args>
1341 1460 : __shared_ptr(_Sp_alloc_shared_tag<_Alloc> __tag, _Args&&... __args)
1342 1460 : : _M_ptr(), _M_refcount(_M_ptr, __tag, std::forward<_Args>(__args)...)
1343 1460 : { _M_enable_shared_from_this_with(_M_ptr); }
1344 :
1345 : template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
1346 : typename... _Args>
1347 : friend __shared_ptr<_Tp1, _Lp1>
1348 : __allocate_shared(const _Alloc& __a, _Args&&... __args);
1349 :
1350 : // This constructor is used by __weak_ptr::lock() and
1351 : // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t).
1352 636 : __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t)
1353 636 : : _M_refcount(__r._M_refcount, std::nothrow)
1354 : {
1355 636 : _M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr;
1356 636 : }
1357 :
1358 : friend class __weak_ptr<_Tp, _Lp>;
1359 :
1360 : private:
1361 :
1362 : template<typename _Yp>
1363 : using __esft_base_t = decltype(__enable_shared_from_this_base(
1364 : std::declval<const __shared_count<_Lp>&>(),
1365 : std::declval<_Yp*>()));
1366 :
1367 : // Detect an accessible and unambiguous enable_shared_from_this base.
1368 : template<typename _Yp, typename = void>
1369 : struct __has_esft_base
1370 : : false_type { };
1371 :
1372 : template<typename _Yp>
1373 : struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>>
1374 : : __not_<is_array<_Tp>> { }; // No enable shared_from_this for arrays
1375 :
1376 : template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
1377 : typename enable_if<__has_esft_base<_Yp2>::value>::type
1378 : _M_enable_shared_from_this_with(_Yp* __p) noexcept
1379 : {
1380 : if (auto __base = __enable_shared_from_this_base(_M_refcount, __p))
1381 : __base->_M_weak_assign(const_cast<_Yp2*>(__p), _M_refcount);
1382 : }
1383 :
1384 : template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
1385 : typename enable_if<!__has_esft_base<_Yp2>::value>::type
1386 1460 : _M_enable_shared_from_this_with(_Yp*) noexcept
1387 1460 : { }
1388 :
1389 : void*
1390 : _M_get_deleter(const std::type_info& __ti) const noexcept
1391 : { return _M_refcount._M_get_deleter(__ti); }
1392 :
1393 : template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1394 : template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1395 :
1396 : template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
1397 : friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&) noexcept;
1398 :
1399 : template<typename _Del, typename _Tp1>
1400 : friend _Del* get_deleter(const shared_ptr<_Tp1>&) noexcept;
1401 :
1402 : element_type* _M_ptr; // Contained pointer.
1403 : __shared_count<_Lp> _M_refcount; // Reference counter.
1404 : };
1405 :
1406 :
1407 : // 20.7.2.2.7 shared_ptr comparisons
1408 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1409 : inline bool
1410 : operator==(const __shared_ptr<_Tp1, _Lp>& __a,
1411 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1412 : { return __a.get() == __b.get(); }
1413 :
1414 : template<typename _Tp, _Lock_policy _Lp>
1415 : inline bool
1416 : operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1417 : { return !__a; }
1418 :
1419 : template<typename _Tp, _Lock_policy _Lp>
1420 : inline bool
1421 : operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1422 : { return !__a; }
1423 :
1424 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1425 : inline bool
1426 : operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
1427 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1428 : { return __a.get() != __b.get(); }
1429 :
1430 : template<typename _Tp, _Lock_policy _Lp>
1431 : inline bool
1432 : operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1433 : { return (bool)__a; }
1434 :
1435 : template<typename _Tp, _Lock_policy _Lp>
1436 : inline bool
1437 : operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1438 : { return (bool)__a; }
1439 :
1440 : template<typename _Tp, typename _Up, _Lock_policy _Lp>
1441 : inline bool
1442 : operator<(const __shared_ptr<_Tp, _Lp>& __a,
1443 : const __shared_ptr<_Up, _Lp>& __b) noexcept
1444 : {
1445 : using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1446 : using _Up_elt = typename __shared_ptr<_Up, _Lp>::element_type;
1447 : using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type;
1448 : return less<_Vp>()(__a.get(), __b.get());
1449 : }
1450 :
1451 : template<typename _Tp, _Lock_policy _Lp>
1452 : inline bool
1453 : operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1454 : {
1455 : using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1456 : return less<_Tp_elt*>()(__a.get(), nullptr);
1457 : }
1458 :
1459 : template<typename _Tp, _Lock_policy _Lp>
1460 : inline bool
1461 : operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1462 : {
1463 : using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type;
1464 : return less<_Tp_elt*>()(nullptr, __a.get());
1465 : }
1466 :
1467 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1468 : inline bool
1469 : operator<=(const __shared_ptr<_Tp1, _Lp>& __a,
1470 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1471 : { return !(__b < __a); }
1472 :
1473 : template<typename _Tp, _Lock_policy _Lp>
1474 : inline bool
1475 : operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1476 : { return !(nullptr < __a); }
1477 :
1478 : template<typename _Tp, _Lock_policy _Lp>
1479 : inline bool
1480 : operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1481 : { return !(__a < nullptr); }
1482 :
1483 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1484 : inline bool
1485 : operator>(const __shared_ptr<_Tp1, _Lp>& __a,
1486 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1487 : { return (__b < __a); }
1488 :
1489 : template<typename _Tp, _Lock_policy _Lp>
1490 : inline bool
1491 : operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1492 : { return nullptr < __a; }
1493 :
1494 : template<typename _Tp, _Lock_policy _Lp>
1495 : inline bool
1496 : operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1497 : { return __a < nullptr; }
1498 :
1499 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1500 : inline bool
1501 : operator>=(const __shared_ptr<_Tp1, _Lp>& __a,
1502 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1503 : { return !(__a < __b); }
1504 :
1505 : template<typename _Tp, _Lock_policy _Lp>
1506 : inline bool
1507 : operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1508 : { return !(__a < nullptr); }
1509 :
1510 : template<typename _Tp, _Lock_policy _Lp>
1511 : inline bool
1512 : operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1513 : { return !(nullptr < __a); }
1514 :
1515 : template<typename _Sp>
1516 : struct _Sp_less : public binary_function<_Sp, _Sp, bool>
1517 : {
1518 : bool
1519 : operator()(const _Sp& __lhs, const _Sp& __rhs) const noexcept
1520 : {
1521 : typedef typename _Sp::element_type element_type;
1522 : return std::less<element_type*>()(__lhs.get(), __rhs.get());
1523 : }
1524 : };
1525 :
1526 : template<typename _Tp, _Lock_policy _Lp>
1527 : struct less<__shared_ptr<_Tp, _Lp>>
1528 : : public _Sp_less<__shared_ptr<_Tp, _Lp>>
1529 : { };
1530 :
1531 : // 20.7.2.2.8 shared_ptr specialized algorithms.
1532 : template<typename _Tp, _Lock_policy _Lp>
1533 : inline void
1534 : swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept
1535 : { __a.swap(__b); }
1536 :
1537 : // 20.7.2.2.9 shared_ptr casts
1538 :
1539 : // The seemingly equivalent code:
1540 : // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
1541 : // will eventually result in undefined behaviour, attempting to
1542 : // delete the same object twice.
1543 : /// static_pointer_cast
1544 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1545 : inline __shared_ptr<_Tp, _Lp>
1546 : static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1547 : {
1548 : using _Sp = __shared_ptr<_Tp, _Lp>;
1549 : return _Sp(__r, static_cast<typename _Sp::element_type*>(__r.get()));
1550 : }
1551 :
1552 : // The seemingly equivalent code:
1553 : // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
1554 : // will eventually result in undefined behaviour, attempting to
1555 : // delete the same object twice.
1556 : /// const_pointer_cast
1557 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1558 : inline __shared_ptr<_Tp, _Lp>
1559 : const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1560 : {
1561 : using _Sp = __shared_ptr<_Tp, _Lp>;
1562 : return _Sp(__r, const_cast<typename _Sp::element_type*>(__r.get()));
1563 : }
1564 :
1565 : // The seemingly equivalent code:
1566 : // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
1567 : // will eventually result in undefined behaviour, attempting to
1568 : // delete the same object twice.
1569 : /// dynamic_pointer_cast
1570 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1571 : inline __shared_ptr<_Tp, _Lp>
1572 : dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1573 : {
1574 : using _Sp = __shared_ptr<_Tp, _Lp>;
1575 : if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
1576 : return _Sp(__r, __p);
1577 : return _Sp();
1578 : }
1579 :
1580 : #if __cplusplus > 201402L
1581 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1582 : inline __shared_ptr<_Tp, _Lp>
1583 : reinterpret_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1584 : {
1585 : using _Sp = __shared_ptr<_Tp, _Lp>;
1586 : return _Sp(__r, reinterpret_cast<typename _Sp::element_type*>(__r.get()));
1587 : }
1588 : #endif
1589 :
1590 : template<typename _Tp, _Lock_policy _Lp>
1591 : class __weak_ptr
1592 : {
1593 : template<typename _Yp, typename _Res = void>
1594 : using _Compatible = typename
1595 : enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type;
1596 :
1597 : // Constraint for assignment from shared_ptr and weak_ptr:
1598 : template<typename _Yp>
1599 : using _Assignable = _Compatible<_Yp, __weak_ptr&>;
1600 :
1601 : public:
1602 : using element_type = typename remove_extent<_Tp>::type;
1603 :
1604 : constexpr __weak_ptr() noexcept
1605 : : _M_ptr(nullptr), _M_refcount()
1606 : { }
1607 :
1608 : __weak_ptr(const __weak_ptr&) noexcept = default;
1609 :
1610 423 : ~__weak_ptr() = default;
1611 :
1612 : // The "obvious" converting constructor implementation:
1613 : //
1614 : // template<typename _Tp1>
1615 : // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
1616 : // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
1617 : // { }
1618 : //
1619 : // has a serious problem.
1620 : //
1621 : // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
1622 : // conversion may require access to *__r._M_ptr (virtual inheritance).
1623 : //
1624 : // It is not possible to avoid spurious access violations since
1625 : // in multithreaded programs __r._M_ptr may be invalidated at any point.
1626 : template<typename _Yp, typename = _Compatible<_Yp>>
1627 : __weak_ptr(const __weak_ptr<_Yp, _Lp>& __r) noexcept
1628 : : _M_refcount(__r._M_refcount)
1629 : { _M_ptr = __r.lock().get(); }
1630 :
1631 : template<typename _Yp, typename = _Compatible<_Yp>>
1632 167 : __weak_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1633 167 : : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1634 167 : { }
1635 :
1636 256 : __weak_ptr(__weak_ptr&& __r) noexcept
1637 256 : : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount))
1638 256 : { __r._M_ptr = nullptr; }
1639 :
1640 : template<typename _Yp, typename = _Compatible<_Yp>>
1641 : __weak_ptr(__weak_ptr<_Yp, _Lp>&& __r) noexcept
1642 : : _M_ptr(__r.lock().get()), _M_refcount(std::move(__r._M_refcount))
1643 : { __r._M_ptr = nullptr; }
1644 :
1645 : __weak_ptr&
1646 : operator=(const __weak_ptr& __r) noexcept = default;
1647 :
1648 : template<typename _Yp>
1649 : _Assignable<_Yp>
1650 : operator=(const __weak_ptr<_Yp, _Lp>& __r) noexcept
1651 : {
1652 : _M_ptr = __r.lock().get();
1653 : _M_refcount = __r._M_refcount;
1654 : return *this;
1655 : }
1656 :
1657 : template<typename _Yp>
1658 : _Assignable<_Yp>
1659 : operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept
1660 : {
1661 : _M_ptr = __r._M_ptr;
1662 : _M_refcount = __r._M_refcount;
1663 : return *this;
1664 : }
1665 :
1666 : __weak_ptr&
1667 92 : operator=(__weak_ptr&& __r) noexcept
1668 : {
1669 92 : _M_ptr = __r._M_ptr;
1670 92 : _M_refcount = std::move(__r._M_refcount);
1671 92 : __r._M_ptr = nullptr;
1672 92 : return *this;
1673 : }
1674 :
1675 : template<typename _Yp>
1676 : _Assignable<_Yp>
1677 : operator=(__weak_ptr<_Yp, _Lp>&& __r) noexcept
1678 : {
1679 : _M_ptr = __r.lock().get();
1680 : _M_refcount = std::move(__r._M_refcount);
1681 : __r._M_ptr = nullptr;
1682 : return *this;
1683 : }
1684 :
1685 : __shared_ptr<_Tp, _Lp>
1686 : lock() const noexcept
1687 : { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); }
1688 :
1689 : long
1690 : use_count() const noexcept
1691 : { return _M_refcount._M_get_use_count(); }
1692 :
1693 : bool
1694 : expired() const noexcept
1695 : { return _M_refcount._M_get_use_count() == 0; }
1696 :
1697 : template<typename _Tp1>
1698 : bool
1699 : owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const noexcept
1700 : { return _M_refcount._M_less(__rhs._M_refcount); }
1701 :
1702 : template<typename _Tp1>
1703 : bool
1704 : owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const noexcept
1705 : { return _M_refcount._M_less(__rhs._M_refcount); }
1706 :
1707 : void
1708 : reset() noexcept
1709 : { __weak_ptr().swap(*this); }
1710 :
1711 : void
1712 0 : swap(__weak_ptr& __s) noexcept
1713 : {
1714 0 : std::swap(_M_ptr, __s._M_ptr);
1715 0 : _M_refcount._M_swap(__s._M_refcount);
1716 0 : }
1717 :
1718 : private:
1719 : // Used by __enable_shared_from_this.
1720 : void
1721 : _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept
1722 : {
1723 : if (use_count() == 0)
1724 : {
1725 : _M_ptr = __ptr;
1726 : _M_refcount = __refcount;
1727 : }
1728 : }
1729 :
1730 : template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1731 : template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1732 : friend class __enable_shared_from_this<_Tp, _Lp>;
1733 : friend class enable_shared_from_this<_Tp>;
1734 :
1735 : element_type* _M_ptr; // Contained pointer.
1736 : __weak_count<_Lp> _M_refcount; // Reference counter.
1737 : };
1738 :
1739 : // 20.7.2.3.6 weak_ptr specialized algorithms.
1740 : template<typename _Tp, _Lock_policy _Lp>
1741 : inline void
1742 : swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept
1743 : { __a.swap(__b); }
1744 :
1745 : template<typename _Tp, typename _Tp1>
1746 : struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool>
1747 : {
1748 : bool
1749 : operator()(const _Tp& __lhs, const _Tp& __rhs) const noexcept
1750 : { return __lhs.owner_before(__rhs); }
1751 :
1752 : bool
1753 : operator()(const _Tp& __lhs, const _Tp1& __rhs) const noexcept
1754 : { return __lhs.owner_before(__rhs); }
1755 :
1756 : bool
1757 : operator()(const _Tp1& __lhs, const _Tp& __rhs) const noexcept
1758 : { return __lhs.owner_before(__rhs); }
1759 : };
1760 :
1761 : template<>
1762 : struct _Sp_owner_less<void, void>
1763 : {
1764 : template<typename _Tp, typename _Up>
1765 : auto
1766 : operator()(const _Tp& __lhs, const _Up& __rhs) const noexcept
1767 : -> decltype(__lhs.owner_before(__rhs))
1768 : { return __lhs.owner_before(__rhs); }
1769 :
1770 : using is_transparent = void;
1771 : };
1772 :
1773 : template<typename _Tp, _Lock_policy _Lp>
1774 : struct owner_less<__shared_ptr<_Tp, _Lp>>
1775 : : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>
1776 : { };
1777 :
1778 : template<typename _Tp, _Lock_policy _Lp>
1779 : struct owner_less<__weak_ptr<_Tp, _Lp>>
1780 : : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>>
1781 : { };
1782 :
1783 :
1784 : template<typename _Tp, _Lock_policy _Lp>
1785 : class __enable_shared_from_this
1786 : {
1787 : protected:
1788 : constexpr __enable_shared_from_this() noexcept { }
1789 :
1790 : __enable_shared_from_this(const __enable_shared_from_this&) noexcept { }
1791 :
1792 : __enable_shared_from_this&
1793 : operator=(const __enable_shared_from_this&) noexcept
1794 : { return *this; }
1795 :
1796 : ~__enable_shared_from_this() { }
1797 :
1798 : public:
1799 : __shared_ptr<_Tp, _Lp>
1800 : shared_from_this()
1801 : { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
1802 :
1803 : __shared_ptr<const _Tp, _Lp>
1804 : shared_from_this() const
1805 : { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
1806 :
1807 : #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
1808 : __weak_ptr<_Tp, _Lp>
1809 : weak_from_this() noexcept
1810 : { return this->_M_weak_this; }
1811 :
1812 : __weak_ptr<const _Tp, _Lp>
1813 : weak_from_this() const noexcept
1814 : { return this->_M_weak_this; }
1815 : #endif
1816 :
1817 : private:
1818 : template<typename _Tp1>
1819 : void
1820 : _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept
1821 : { _M_weak_this._M_assign(__p, __n); }
1822 :
1823 : friend const __enable_shared_from_this*
1824 : __enable_shared_from_this_base(const __shared_count<_Lp>&,
1825 : const __enable_shared_from_this* __p)
1826 : { return __p; }
1827 :
1828 : template<typename, _Lock_policy>
1829 : friend class __shared_ptr;
1830 :
1831 : mutable __weak_ptr<_Tp, _Lp> _M_weak_this;
1832 : };
1833 :
1834 : template<typename _Tp, _Lock_policy _Lp, typename _Alloc, typename... _Args>
1835 : inline __shared_ptr<_Tp, _Lp>
1836 : __allocate_shared(const _Alloc& __a, _Args&&... __args)
1837 : {
1838 : return __shared_ptr<_Tp, _Lp>(_Sp_alloc_shared_tag<_Alloc>{__a},
1839 : std::forward<_Args>(__args)...);
1840 : }
1841 :
1842 : template<typename _Tp, _Lock_policy _Lp, typename... _Args>
1843 : inline __shared_ptr<_Tp, _Lp>
1844 : __make_shared(_Args&&... __args)
1845 : {
1846 : typedef typename std::remove_const<_Tp>::type _Tp_nc;
1847 : return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
1848 : std::forward<_Args>(__args)...);
1849 : }
1850 :
1851 : /// std::hash specialization for __shared_ptr.
1852 : template<typename _Tp, _Lock_policy _Lp>
1853 : struct hash<__shared_ptr<_Tp, _Lp>>
1854 : : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>>
1855 : {
1856 : size_t
1857 : operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept
1858 : {
1859 : return hash<typename __shared_ptr<_Tp, _Lp>::element_type*>()(
1860 : __s.get());
1861 : }
1862 : };
1863 :
1864 : _GLIBCXX_END_NAMESPACE_VERSION
1865 : } // namespace
1866 :
1867 : #endif // _SHARED_PTR_BASE_H
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