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1 : // shared_ptr and weak_ptr implementation details -*- C++ -*-
2 :
3 : // Copyright (C) 2007-2016 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 <ext/aligned_buffer.h>
55 :
56 : namespace std _GLIBCXX_VISIBILITY(default)
57 : {
58 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
59 :
60 : #if _GLIBCXX_USE_DEPRECATED
61 : template<typename> class auto_ptr;
62 : #endif
63 :
64 : /**
65 : * @brief Exception possibly thrown by @c shared_ptr.
66 : * @ingroup exceptions
67 : */
68 0 : class bad_weak_ptr : public std::exception
69 : {
70 : public:
71 : virtual char const* what() const noexcept;
72 :
73 : virtual ~bad_weak_ptr() noexcept;
74 : };
75 :
76 : // Substitute for bad_weak_ptr object in the case of -fno-exceptions.
77 : inline void
78 0 : __throw_bad_weak_ptr()
79 0 : { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); }
80 :
81 : using __gnu_cxx::_Lock_policy;
82 : using __gnu_cxx::__default_lock_policy;
83 : using __gnu_cxx::_S_single;
84 : using __gnu_cxx::_S_mutex;
85 : using __gnu_cxx::_S_atomic;
86 :
87 : // Empty helper class except when the template argument is _S_mutex.
88 : template<_Lock_policy _Lp>
89 3715 : class _Mutex_base
90 : {
91 : protected:
92 : // The atomic policy uses fully-fenced builtins, single doesn't care.
93 : enum { _S_need_barriers = 0 };
94 : };
95 :
96 : template<>
97 : class _Mutex_base<_S_mutex>
98 : : public __gnu_cxx::__mutex
99 : {
100 : protected:
101 : // This policy is used when atomic builtins are not available.
102 : // The replacement atomic operations might not have the necessary
103 : // memory barriers.
104 : enum { _S_need_barriers = 1 };
105 : };
106 :
107 : template<_Lock_policy _Lp = __default_lock_policy>
108 : class _Sp_counted_base
109 : : public _Mutex_base<_Lp>
110 : {
111 : public:
112 3715 : _Sp_counted_base() noexcept
113 3715 : : _M_use_count(1), _M_weak_count(1) { }
114 :
115 : virtual
116 3575 : ~_Sp_counted_base() noexcept
117 3575 : { }
118 :
119 : // Called when _M_use_count drops to zero, to release the resources
120 : // managed by *this.
121 : virtual void
122 : _M_dispose() noexcept = 0;
123 :
124 : // Called when _M_weak_count drops to zero.
125 : virtual void
126 0 : _M_destroy() noexcept
127 0 : { delete this; }
128 :
129 : virtual void*
130 : _M_get_deleter(const std::type_info&) noexcept = 0;
131 :
132 : void
133 4118 : _M_add_ref_copy()
134 4118 : { __gnu_cxx::__atomic_add_dispatch(&_M_use_count, 1); }
135 :
136 : void
137 : _M_add_ref_lock();
138 :
139 : bool
140 : _M_add_ref_lock_nothrow();
141 :
142 : void
143 37814 : _M_release() noexcept
144 : {
145 : // Be race-detector-friendly. For more info see bits/c++config.
146 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count);
147 37814 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, -1) == 1)
148 : {
149 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count);
150 3575 : _M_dispose();
151 : // There must be a memory barrier between dispose() and destroy()
152 : // to ensure that the effects of dispose() are observed in the
153 : // thread that runs destroy().
154 : // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html
155 : if (_Mutex_base<_Lp>::_S_need_barriers)
156 : {
157 : __atomic_thread_fence (__ATOMIC_ACQ_REL);
158 : }
159 :
160 : // Be race-detector-friendly. For more info see bits/c++config.
161 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
162 3575 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count,
163 : -1) == 1)
164 : {
165 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
166 3573 : _M_destroy();
167 : }
168 : }
169 37814 : }
170 :
171 : void
172 58114 : _M_weak_add_ref() noexcept
173 58114 : { __gnu_cxx::__atomic_add_dispatch(&_M_weak_count, 1); }
174 :
175 : void
176 57852 : _M_weak_release() noexcept
177 : {
178 : // Be race-detector-friendly. For more info see bits/c++config.
179 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count);
180 57852 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_weak_count, -1) == 1)
181 : {
182 : _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count);
183 : if (_Mutex_base<_Lp>::_S_need_barriers)
184 : {
185 : // See _M_release(),
186 : // destroy() must observe results of dispose()
187 : __atomic_thread_fence (__ATOMIC_ACQ_REL);
188 : }
189 2 : _M_destroy();
190 : }
191 57852 : }
192 :
193 : long
194 144703 : _M_get_use_count() const noexcept
195 : {
196 : // No memory barrier is used here so there is no synchronization
197 : // with other threads.
198 144703 : return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED);
199 : }
200 :
201 : private:
202 : _Sp_counted_base(_Sp_counted_base const&) = delete;
203 : _Sp_counted_base& operator=(_Sp_counted_base const&) = delete;
204 :
205 : _Atomic_word _M_use_count; // #shared
206 : _Atomic_word _M_weak_count; // #weak + (#shared != 0)
207 : };
208 :
209 : template<>
210 : inline void
211 : _Sp_counted_base<_S_single>::
212 : _M_add_ref_lock()
213 : {
214 : if (_M_use_count == 0)
215 : __throw_bad_weak_ptr();
216 : ++_M_use_count;
217 : }
218 :
219 : template<>
220 : inline void
221 : _Sp_counted_base<_S_mutex>::
222 : _M_add_ref_lock()
223 : {
224 : __gnu_cxx::__scoped_lock sentry(*this);
225 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
226 : {
227 : _M_use_count = 0;
228 : __throw_bad_weak_ptr();
229 : }
230 : }
231 :
232 : template<>
233 : inline void
234 621 : _Sp_counted_base<_S_atomic>::
235 : _M_add_ref_lock()
236 : {
237 : // Perform lock-free add-if-not-zero operation.
238 621 : _Atomic_word __count = _M_get_use_count();
239 621 : do
240 : {
241 621 : if (__count == 0)
242 0 : __throw_bad_weak_ptr();
243 : // Replace the current counter value with the old value + 1, as
244 : // long as it's not changed meanwhile.
245 : }
246 621 : while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
247 : true, __ATOMIC_ACQ_REL,
248 : __ATOMIC_RELAXED));
249 621 : }
250 :
251 : template<>
252 : inline bool
253 : _Sp_counted_base<_S_single>::
254 : _M_add_ref_lock_nothrow()
255 : {
256 : if (_M_use_count == 0)
257 : return false;
258 : ++_M_use_count;
259 : return true;
260 : }
261 :
262 : template<>
263 : inline bool
264 : _Sp_counted_base<_S_mutex>::
265 : _M_add_ref_lock_nothrow()
266 : {
267 : __gnu_cxx::__scoped_lock sentry(*this);
268 : if (__gnu_cxx::__exchange_and_add_dispatch(&_M_use_count, 1) == 0)
269 : {
270 : _M_use_count = 0;
271 : return false;
272 : }
273 : return true;
274 : }
275 :
276 : template<>
277 : inline bool
278 29500 : _Sp_counted_base<_S_atomic>::
279 : _M_add_ref_lock_nothrow()
280 : {
281 : // Perform lock-free add-if-not-zero operation.
282 29500 : _Atomic_word __count = _M_get_use_count();
283 29500 : do
284 : {
285 29500 : if (__count == 0)
286 0 : return false;
287 : // Replace the current counter value with the old value + 1, as
288 : // long as it's not changed meanwhile.
289 : }
290 29500 : while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1,
291 : true, __ATOMIC_ACQ_REL,
292 : __ATOMIC_RELAXED));
293 29500 : return true;
294 : }
295 :
296 : template<>
297 : inline void
298 : _Sp_counted_base<_S_single>::_M_add_ref_copy()
299 : { ++_M_use_count; }
300 :
301 : template<>
302 : inline void
303 : _Sp_counted_base<_S_single>::_M_release() noexcept
304 : {
305 : if (--_M_use_count == 0)
306 : {
307 : _M_dispose();
308 : if (--_M_weak_count == 0)
309 : _M_destroy();
310 : }
311 : }
312 :
313 : template<>
314 : inline void
315 : _Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept
316 : { ++_M_weak_count; }
317 :
318 : template<>
319 : inline void
320 : _Sp_counted_base<_S_single>::_M_weak_release() noexcept
321 : {
322 : if (--_M_weak_count == 0)
323 : _M_destroy();
324 : }
325 :
326 : template<>
327 : inline long
328 : _Sp_counted_base<_S_single>::_M_get_use_count() const noexcept
329 : { return _M_use_count; }
330 :
331 :
332 : // Forward declarations.
333 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
334 : class __shared_ptr;
335 :
336 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
337 : class __weak_ptr;
338 :
339 : template<typename _Tp, _Lock_policy _Lp = __default_lock_policy>
340 : class __enable_shared_from_this;
341 :
342 : template<typename _Tp>
343 : class shared_ptr;
344 :
345 : template<typename _Tp>
346 : class weak_ptr;
347 :
348 : template<typename _Tp>
349 : struct owner_less;
350 :
351 : template<typename _Tp>
352 : class enable_shared_from_this;
353 :
354 : template<_Lock_policy _Lp = __default_lock_policy>
355 : class __weak_count;
356 :
357 : template<_Lock_policy _Lp = __default_lock_policy>
358 : class __shared_count;
359 :
360 :
361 : // Counted ptr with no deleter or allocator support
362 : template<typename _Ptr, _Lock_policy _Lp>
363 6496 : class _Sp_counted_ptr final : public _Sp_counted_base<_Lp>
364 : {
365 : public:
366 : explicit
367 3382 : _Sp_counted_ptr(_Ptr __p) noexcept
368 3382 : : _M_ptr(__p) { }
369 :
370 : virtual void
371 3248 : _M_dispose() noexcept
372 3248 : { delete _M_ptr; }
373 :
374 : virtual void
375 3248 : _M_destroy() noexcept
376 3248 : { delete this; }
377 :
378 : virtual void*
379 0 : _M_get_deleter(const std::type_info&) noexcept
380 0 : { return nullptr; }
381 :
382 : _Sp_counted_ptr(const _Sp_counted_ptr&) = delete;
383 : _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete;
384 :
385 : private:
386 : _Ptr _M_ptr;
387 : };
388 :
389 : template<>
390 : inline void
391 : _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { }
392 :
393 : template<>
394 : inline void
395 : _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { }
396 :
397 : template<>
398 : inline void
399 : _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { }
400 :
401 : template<int _Nm, typename _Tp,
402 : bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
403 : struct _Sp_ebo_helper;
404 :
405 : /// Specialization using EBO.
406 : template<int _Nm, typename _Tp>
407 : struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp
408 : {
409 333 : explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { }
410 :
411 : static _Tp&
412 327 : _S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); }
413 : };
414 :
415 : /// Specialization not using EBO.
416 : template<int _Nm, typename _Tp>
417 : struct _Sp_ebo_helper<_Nm, _Tp, false>
418 : {
419 333 : explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { }
420 :
421 : static _Tp&
422 327 : _S_get(_Sp_ebo_helper& __eboh)
423 327 : { return __eboh._M_tp; }
424 :
425 : private:
426 : _Tp _M_tp;
427 : };
428 :
429 : // Support for custom deleter and/or allocator
430 : template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
431 : class _Sp_counted_deleter final : public _Sp_counted_base<_Lp>
432 : {
433 : class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc>
434 : {
435 : typedef _Sp_ebo_helper<0, _Deleter> _Del_base;
436 : typedef _Sp_ebo_helper<1, _Alloc> _Alloc_base;
437 :
438 : public:
439 333 : _Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
440 333 : : _M_ptr(__p), _Del_base(__d), _Alloc_base(__a)
441 333 : { }
442 :
443 327 : _Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); }
444 327 : _Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); }
445 :
446 : _Ptr _M_ptr;
447 : };
448 :
449 : public:
450 : using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_deleter>;
451 :
452 : // __d(__p) must not throw.
453 : _Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept
454 : : _M_impl(__p, __d, _Alloc()) { }
455 :
456 : // __d(__p) must not throw.
457 333 : _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept
458 333 : : _M_impl(__p, __d, __a) { }
459 :
460 327 : ~_Sp_counted_deleter() noexcept { }
461 :
462 : virtual void
463 327 : _M_dispose() noexcept
464 327 : { _M_impl._M_del()(_M_impl._M_ptr); }
465 :
466 : virtual void
467 327 : _M_destroy() noexcept
468 : {
469 654 : __allocator_type __a(_M_impl._M_alloc());
470 654 : __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
471 327 : this->~_Sp_counted_deleter();
472 327 : }
473 :
474 : virtual void*
475 0 : _M_get_deleter(const std::type_info& __ti) noexcept
476 : {
477 : #if __cpp_rtti
478 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
479 : // 2400. shared_ptr's get_deleter() should use addressof()
480 0 : return __ti == typeid(_Deleter)
481 0 : ? std::__addressof(_M_impl._M_del())
482 0 : : nullptr;
483 : #else
484 : return nullptr;
485 : #endif
486 : }
487 :
488 : private:
489 : _Impl _M_impl;
490 : };
491 :
492 : // helpers for make_shared / allocate_shared
493 :
494 : struct _Sp_make_shared_tag { };
495 :
496 : template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
497 : class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp>
498 : {
499 : class _Impl : _Sp_ebo_helper<0, _Alloc>
500 : {
501 : typedef _Sp_ebo_helper<0, _Alloc> _A_base;
502 :
503 : public:
504 : explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { }
505 :
506 : _Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); }
507 :
508 : __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
509 : };
510 :
511 : public:
512 : using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
513 :
514 : template<typename... _Args>
515 : _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
516 : : _M_impl(__a)
517 : {
518 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
519 : // 2070. allocate_shared should use allocator_traits<A>::construct
520 : allocator_traits<_Alloc>::construct(__a, _M_ptr(),
521 : std::forward<_Args>(__args)...); // might throw
522 : }
523 :
524 : ~_Sp_counted_ptr_inplace() noexcept { }
525 :
526 : virtual void
527 : _M_dispose() noexcept
528 : {
529 : allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr());
530 : }
531 :
532 : // Override because the allocator needs to know the dynamic type
533 : virtual void
534 : _M_destroy() noexcept
535 : {
536 : __allocator_type __a(_M_impl._M_alloc());
537 : __allocated_ptr<__allocator_type> __guard_ptr{ __a, this };
538 : this->~_Sp_counted_ptr_inplace();
539 : }
540 :
541 : // Sneaky trick so __shared_ptr can get the managed pointer
542 : virtual void*
543 : _M_get_deleter(const std::type_info& __ti) noexcept
544 : {
545 : #if __cpp_rtti
546 : if (__ti == typeid(_Sp_make_shared_tag))
547 : return const_cast<typename remove_cv<_Tp>::type*>(_M_ptr());
548 : #endif
549 : return nullptr;
550 : }
551 :
552 : private:
553 : _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); }
554 :
555 : _Impl _M_impl;
556 : };
557 :
558 :
559 : template<_Lock_policy _Lp>
560 : class __shared_count
561 : {
562 : public:
563 3626 : constexpr __shared_count() noexcept : _M_pi(0)
564 3626 : { }
565 :
566 : template<typename _Ptr>
567 : explicit
568 3382 : __shared_count(_Ptr __p) : _M_pi(0)
569 : {
570 : __try
571 : {
572 3382 : _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p);
573 : }
574 0 : __catch(...)
575 : {
576 0 : delete __p;
577 0 : __throw_exception_again;
578 : }
579 3382 : }
580 :
581 : template<typename _Ptr, typename _Deleter>
582 333 : __shared_count(_Ptr __p, _Deleter __d)
583 333 : : __shared_count(__p, std::move(__d), allocator<void>())
584 333 : { }
585 :
586 : template<typename _Ptr, typename _Deleter, typename _Alloc>
587 333 : __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
588 : {
589 : typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
590 : __try
591 : {
592 666 : typename _Sp_cd_type::__allocator_type __a2(__a);
593 666 : auto __guard = std::__allocate_guarded(__a2);
594 333 : _Sp_cd_type* __mem = __guard.get();
595 333 : ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a));
596 333 : _M_pi = __mem;
597 333 : __guard = nullptr;
598 : }
599 0 : __catch(...)
600 : {
601 0 : __d(__p); // Call _Deleter on __p.
602 0 : __throw_exception_again;
603 : }
604 333 : }
605 :
606 : template<typename _Tp, typename _Alloc, typename... _Args>
607 : __shared_count(_Sp_make_shared_tag, _Tp*, const _Alloc& __a,
608 : _Args&&... __args)
609 : : _M_pi(0)
610 : {
611 : typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
612 : typename _Sp_cp_type::__allocator_type __a2(__a);
613 : auto __guard = std::__allocate_guarded(__a2);
614 : _Sp_cp_type* __mem = __guard.get();
615 : ::new (__mem) _Sp_cp_type(std::move(__a),
616 : std::forward<_Args>(__args)...);
617 : _M_pi = __mem;
618 : __guard = nullptr;
619 : }
620 :
621 : #if _GLIBCXX_USE_DEPRECATED
622 : // Special case for auto_ptr<_Tp> to provide the strong guarantee.
623 : template<typename _Tp>
624 : explicit
625 : __shared_count(std::auto_ptr<_Tp>&& __r);
626 : #endif
627 :
628 : // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee.
629 : template<typename _Tp, typename _Del>
630 : explicit
631 : __shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0)
632 : {
633 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
634 : // 2415. Inconsistency between unique_ptr and shared_ptr
635 : if (__r.get() == nullptr)
636 : return;
637 :
638 : using _Ptr = typename unique_ptr<_Tp, _Del>::pointer;
639 : using _Del2 = typename conditional<is_reference<_Del>::value,
640 : reference_wrapper<typename remove_reference<_Del>::type>,
641 : _Del>::type;
642 : using _Sp_cd_type
643 : = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>;
644 : using _Alloc = allocator<_Sp_cd_type>;
645 : using _Alloc_traits = allocator_traits<_Alloc>;
646 : _Alloc __a;
647 : _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1);
648 : _Alloc_traits::construct(__a, __mem, __r.release(),
649 : __r.get_deleter()); // non-throwing
650 : _M_pi = __mem;
651 : }
652 :
653 : // Throw bad_weak_ptr when __r._M_get_use_count() == 0.
654 : explicit __shared_count(const __weak_count<_Lp>& __r);
655 :
656 : // Does not throw if __r._M_get_use_count() == 0, caller must check.
657 : explicit __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t);
658 :
659 41786 : ~__shared_count() noexcept
660 : {
661 41786 : if (_M_pi != nullptr)
662 37814 : _M_pi->_M_release();
663 41786 : }
664 :
665 4163 : __shared_count(const __shared_count& __r) noexcept
666 4163 : : _M_pi(__r._M_pi)
667 : {
668 4163 : if (_M_pi != 0)
669 1036 : _M_pi->_M_add_ref_copy();
670 4163 : }
671 :
672 : __shared_count&
673 3082 : operator=(const __shared_count& __r) noexcept
674 : {
675 3082 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
676 3082 : if (__tmp != _M_pi)
677 : {
678 3082 : if (__tmp != 0)
679 3082 : __tmp->_M_add_ref_copy();
680 3082 : if (_M_pi != 0)
681 0 : _M_pi->_M_release();
682 3082 : _M_pi = __tmp;
683 : }
684 3082 : return *this;
685 : }
686 :
687 : void
688 1369 : _M_swap(__shared_count& __r) noexcept
689 : {
690 1369 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
691 1369 : __r._M_pi = _M_pi;
692 1369 : _M_pi = __tmp;
693 1369 : }
694 :
695 : long
696 29525 : _M_get_use_count() const noexcept
697 29525 : { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; }
698 :
699 : bool
700 0 : _M_unique() const noexcept
701 0 : { return this->_M_get_use_count() == 1; }
702 :
703 : void*
704 : _M_get_deleter(const std::type_info& __ti) const noexcept
705 : { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; }
706 :
707 : bool
708 : _M_less(const __shared_count& __rhs) const noexcept
709 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
710 :
711 : bool
712 : _M_less(const __weak_count<_Lp>& __rhs) const noexcept
713 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
714 :
715 : // Friend function injected into enclosing namespace and found by ADL
716 : friend inline bool
717 : operator==(const __shared_count& __a, const __shared_count& __b) noexcept
718 : { return __a._M_pi == __b._M_pi; }
719 :
720 : private:
721 : friend class __weak_count<_Lp>;
722 :
723 : _Sp_counted_base<_Lp>* _M_pi;
724 : };
725 :
726 :
727 : template<_Lock_policy _Lp>
728 : class __weak_count
729 : {
730 : public:
731 138 : constexpr __weak_count() noexcept : _M_pi(nullptr)
732 138 : { }
733 :
734 38357 : __weak_count(const __shared_count<_Lp>& __r) noexcept
735 38357 : : _M_pi(__r._M_pi)
736 : {
737 38357 : if (_M_pi != nullptr)
738 38332 : _M_pi->_M_weak_add_ref();
739 38357 : }
740 :
741 19644 : __weak_count(const __weak_count& __r) noexcept
742 19644 : : _M_pi(__r._M_pi)
743 : {
744 19644 : if (_M_pi != nullptr)
745 19644 : _M_pi->_M_weak_add_ref();
746 19644 : }
747 :
748 4 : __weak_count(__weak_count&& __r) noexcept
749 4 : : _M_pi(__r._M_pi)
750 4 : { __r._M_pi = nullptr; }
751 :
752 57881 : ~__weak_count() noexcept
753 : {
754 57881 : if (_M_pi != nullptr)
755 57852 : _M_pi->_M_weak_release();
756 57881 : }
757 :
758 : __weak_count&
759 138 : operator=(const __shared_count<_Lp>& __r) noexcept
760 : {
761 138 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
762 138 : if (__tmp != nullptr)
763 138 : __tmp->_M_weak_add_ref();
764 138 : if (_M_pi != nullptr)
765 0 : _M_pi->_M_weak_release();
766 138 : _M_pi = __tmp;
767 138 : return *this;
768 : }
769 :
770 : __weak_count&
771 : operator=(const __weak_count& __r) noexcept
772 : {
773 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
774 : if (__tmp != nullptr)
775 : __tmp->_M_weak_add_ref();
776 : if (_M_pi != nullptr)
777 : _M_pi->_M_weak_release();
778 : _M_pi = __tmp;
779 : return *this;
780 : }
781 :
782 : __weak_count&
783 : operator=(__weak_count&& __r) noexcept
784 : {
785 : if (_M_pi != nullptr)
786 : _M_pi->_M_weak_release();
787 : _M_pi = __r._M_pi;
788 : __r._M_pi = nullptr;
789 : return *this;
790 : }
791 :
792 : void
793 : _M_swap(__weak_count& __r) noexcept
794 : {
795 : _Sp_counted_base<_Lp>* __tmp = __r._M_pi;
796 : __r._M_pi = _M_pi;
797 : _M_pi = __tmp;
798 : }
799 :
800 : long
801 85220 : _M_get_use_count() const noexcept
802 85220 : { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; }
803 :
804 : bool
805 : _M_less(const __weak_count& __rhs) const noexcept
806 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
807 :
808 : bool
809 : _M_less(const __shared_count<_Lp>& __rhs) const noexcept
810 : { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); }
811 :
812 : // Friend function injected into enclosing namespace and found by ADL
813 : friend inline bool
814 : operator==(const __weak_count& __a, const __weak_count& __b) noexcept
815 : { return __a._M_pi == __b._M_pi; }
816 :
817 : private:
818 : friend class __shared_count<_Lp>;
819 :
820 : _Sp_counted_base<_Lp>* _M_pi;
821 : };
822 :
823 : // Now that __weak_count is defined we can define this constructor:
824 : template<_Lock_policy _Lp>
825 : inline
826 621 : __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r)
827 621 : : _M_pi(__r._M_pi)
828 : {
829 621 : if (_M_pi != nullptr)
830 621 : _M_pi->_M_add_ref_lock();
831 : else
832 0 : __throw_bad_weak_ptr();
833 621 : }
834 :
835 : // Now that __weak_count is defined we can define this constructor:
836 : template<_Lock_policy _Lp>
837 : inline
838 29525 : __shared_count<_Lp>::
839 : __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t)
840 29525 : : _M_pi(__r._M_pi)
841 : {
842 29525 : if (_M_pi != nullptr)
843 29500 : if (!_M_pi->_M_add_ref_lock_nothrow())
844 0 : _M_pi = nullptr;
845 29525 : }
846 :
847 : // Support for enable_shared_from_this.
848 :
849 : // Friend of __enable_shared_from_this.
850 : template<_Lock_policy _Lp, typename _Tp1, typename _Tp2>
851 : void
852 : __enable_shared_from_this_helper(const __shared_count<_Lp>&,
853 : const __enable_shared_from_this<_Tp1,
854 : _Lp>*, const _Tp2*) noexcept;
855 :
856 : // Friend of enable_shared_from_this.
857 : template<typename _Tp1, typename _Tp2>
858 : void
859 : __enable_shared_from_this_helper(const __shared_count<>&,
860 : const enable_shared_from_this<_Tp1>*,
861 : const _Tp2*) noexcept;
862 :
863 : template<_Lock_policy _Lp>
864 : inline void
865 3577 : __enable_shared_from_this_helper(const __shared_count<_Lp>&, ...) noexcept
866 3577 : { }
867 :
868 :
869 : template<typename _Tp, _Lock_policy _Lp>
870 3082 : class __shared_ptr
871 : {
872 : template<typename _Ptr>
873 : using _Convertible
874 : = typename enable_if<is_convertible<_Ptr, _Tp*>::value>::type;
875 :
876 : public:
877 : typedef _Tp element_type;
878 :
879 3626 : constexpr __shared_ptr() noexcept
880 3626 : : _M_ptr(0), _M_refcount()
881 3626 : { }
882 :
883 : template<typename _Tp1>
884 3382 : explicit __shared_ptr(_Tp1* __p)
885 3382 : : _M_ptr(__p), _M_refcount(__p)
886 : {
887 : __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
888 : static_assert( !is_void<_Tp1>::value, "incomplete type" );
889 : static_assert( sizeof(_Tp1) > 0, "incomplete type" );
890 3382 : __enable_shared_from_this_helper(_M_refcount, __p, __p);
891 3382 : }
892 :
893 : template<typename _Tp1, typename _Deleter>
894 333 : __shared_ptr(_Tp1* __p, _Deleter __d)
895 333 : : _M_ptr(__p), _M_refcount(__p, __d)
896 : {
897 : __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
898 : // TODO requires _Deleter CopyConstructible and __d(__p) well-formed
899 333 : __enable_shared_from_this_helper(_M_refcount, __p, __p);
900 333 : }
901 :
902 : template<typename _Tp1, typename _Deleter, typename _Alloc>
903 : __shared_ptr(_Tp1* __p, _Deleter __d, _Alloc __a)
904 : : _M_ptr(__p), _M_refcount(__p, __d, std::move(__a))
905 : {
906 : __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
907 : // TODO requires _Deleter CopyConstructible and __d(__p) well-formed
908 : __enable_shared_from_this_helper(_M_refcount, __p, __p);
909 : }
910 :
911 : template<typename _Deleter>
912 : __shared_ptr(nullptr_t __p, _Deleter __d)
913 : : _M_ptr(0), _M_refcount(__p, __d)
914 : { }
915 :
916 : template<typename _Deleter, typename _Alloc>
917 : __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
918 : : _M_ptr(0), _M_refcount(__p, __d, std::move(__a))
919 : { }
920 :
921 : template<typename _Tp1>
922 : __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, _Tp* __p) noexcept
923 : : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws
924 : { }
925 :
926 4111 : __shared_ptr(const __shared_ptr&) noexcept = default;
927 : __shared_ptr& operator=(const __shared_ptr&) noexcept = default;
928 41786 : ~__shared_ptr() = default;
929 :
930 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
931 52 : __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
932 52 : : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
933 52 : { }
934 :
935 : __shared_ptr(__shared_ptr&& __r) noexcept
936 : : _M_ptr(__r._M_ptr), _M_refcount()
937 : {
938 : _M_refcount._M_swap(__r._M_refcount);
939 : __r._M_ptr = 0;
940 : }
941 :
942 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
943 : __shared_ptr(__shared_ptr<_Tp1, _Lp>&& __r) noexcept
944 : : _M_ptr(__r._M_ptr), _M_refcount()
945 : {
946 : _M_refcount._M_swap(__r._M_refcount);
947 : __r._M_ptr = 0;
948 : }
949 :
950 : template<typename _Tp1>
951 621 : explicit __shared_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
952 621 : : _M_refcount(__r._M_refcount) // may throw
953 : {
954 : __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
955 :
956 : // It is now safe to copy __r._M_ptr, as
957 : // _M_refcount(__r._M_refcount) did not throw.
958 621 : _M_ptr = __r._M_ptr;
959 621 : }
960 :
961 : // If an exception is thrown this constructor has no effect.
962 : template<typename _Tp1, typename _Del, typename
963 : = _Convertible<typename unique_ptr<_Tp1, _Del>::pointer>>
964 : __shared_ptr(std::unique_ptr<_Tp1, _Del>&& __r)
965 : : _M_ptr(__r.get()), _M_refcount()
966 : {
967 : __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>)
968 : auto __raw = _S_raw_ptr(__r.get());
969 : _M_refcount = __shared_count<_Lp>(std::move(__r));
970 : __enable_shared_from_this_helper(_M_refcount, __raw, __raw);
971 : }
972 :
973 : #if _GLIBCXX_USE_DEPRECATED
974 : // Postcondition: use_count() == 1 and __r.get() == 0
975 : template<typename _Tp1>
976 : __shared_ptr(std::auto_ptr<_Tp1>&& __r);
977 : #endif
978 :
979 : constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { }
980 :
981 : template<typename _Tp1>
982 : __shared_ptr&
983 : operator=(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
984 : {
985 : _M_ptr = __r._M_ptr;
986 : _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw
987 : return *this;
988 : }
989 :
990 : #if _GLIBCXX_USE_DEPRECATED
991 : template<typename _Tp1>
992 : __shared_ptr&
993 : operator=(std::auto_ptr<_Tp1>&& __r)
994 : {
995 : __shared_ptr(std::move(__r)).swap(*this);
996 : return *this;
997 : }
998 : #endif
999 :
1000 : __shared_ptr&
1001 : operator=(__shared_ptr&& __r) noexcept
1002 : {
1003 : __shared_ptr(std::move(__r)).swap(*this);
1004 : return *this;
1005 : }
1006 :
1007 : template<class _Tp1>
1008 : __shared_ptr&
1009 : operator=(__shared_ptr<_Tp1, _Lp>&& __r) noexcept
1010 : {
1011 : __shared_ptr(std::move(__r)).swap(*this);
1012 : return *this;
1013 : }
1014 :
1015 : template<typename _Tp1, typename _Del>
1016 : __shared_ptr&
1017 : operator=(std::unique_ptr<_Tp1, _Del>&& __r)
1018 : {
1019 : __shared_ptr(std::move(__r)).swap(*this);
1020 : return *this;
1021 : }
1022 :
1023 : void
1024 : reset() noexcept
1025 : { __shared_ptr().swap(*this); }
1026 :
1027 : template<typename _Tp1>
1028 : void
1029 755 : reset(_Tp1* __p) // _Tp1 must be complete.
1030 : {
1031 : // Catch self-reset errors.
1032 : __glibcxx_assert(__p == 0 || __p != _M_ptr);
1033 755 : __shared_ptr(__p).swap(*this);
1034 755 : }
1035 :
1036 : template<typename _Tp1, typename _Deleter>
1037 : void
1038 115 : reset(_Tp1* __p, _Deleter __d)
1039 115 : { __shared_ptr(__p, __d).swap(*this); }
1040 :
1041 : template<typename _Tp1, typename _Deleter, typename _Alloc>
1042 : void
1043 : reset(_Tp1* __p, _Deleter __d, _Alloc __a)
1044 : { __shared_ptr(__p, __d, std::move(__a)).swap(*this); }
1045 :
1046 : // Allow class instantiation when _Tp is [cv-qual] void.
1047 : typename std::add_lvalue_reference<_Tp>::type
1048 0 : operator*() const noexcept
1049 : {
1050 : __glibcxx_assert(_M_ptr != 0);
1051 0 : return *_M_ptr;
1052 : }
1053 :
1054 : _Tp*
1055 10928 : operator->() const noexcept
1056 : {
1057 : _GLIBCXX_DEBUG_PEDASSERT(_M_ptr != 0);
1058 10928 : return _M_ptr;
1059 : }
1060 :
1061 : _Tp*
1062 803 : get() const noexcept
1063 803 : { return _M_ptr; }
1064 :
1065 4664 : explicit operator bool() const // never throws
1066 4664 : { return _M_ptr == 0 ? false : true; }
1067 :
1068 : bool
1069 0 : unique() const noexcept
1070 0 : { return _M_refcount._M_unique(); }
1071 :
1072 : long
1073 : use_count() const noexcept
1074 : { return _M_refcount._M_get_use_count(); }
1075 :
1076 : void
1077 1369 : swap(__shared_ptr<_Tp, _Lp>& __other) noexcept
1078 : {
1079 1369 : std::swap(_M_ptr, __other._M_ptr);
1080 1369 : _M_refcount._M_swap(__other._M_refcount);
1081 1369 : }
1082 :
1083 : template<typename _Tp1>
1084 : bool
1085 : owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const
1086 : { return _M_refcount._M_less(__rhs._M_refcount); }
1087 :
1088 : template<typename _Tp1>
1089 : bool
1090 : owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const
1091 : { return _M_refcount._M_less(__rhs._M_refcount); }
1092 :
1093 : #if __cpp_rtti
1094 : protected:
1095 : // This constructor is non-standard, it is used by allocate_shared.
1096 : template<typename _Alloc, typename... _Args>
1097 : __shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,
1098 : _Args&&... __args)
1099 : : _M_ptr(), _M_refcount(__tag, (_Tp*)0, __a,
1100 : std::forward<_Args>(__args)...)
1101 : {
1102 : // _M_ptr needs to point to the newly constructed object.
1103 : // This relies on _Sp_counted_ptr_inplace::_M_get_deleter.
1104 : void* __p = _M_refcount._M_get_deleter(typeid(__tag));
1105 : _M_ptr = static_cast<_Tp*>(__p);
1106 : __enable_shared_from_this_helper(_M_refcount, _M_ptr, _M_ptr);
1107 : }
1108 : #else
1109 : template<typename _Alloc>
1110 : struct _Deleter
1111 : {
1112 : void operator()(typename _Alloc::value_type* __ptr)
1113 : {
1114 : __allocated_ptr<_Alloc> __guard{ _M_alloc, __ptr };
1115 : allocator_traits<_Alloc>::destroy(_M_alloc, __guard.get());
1116 : }
1117 : _Alloc _M_alloc;
1118 : };
1119 :
1120 : template<typename _Alloc, typename... _Args>
1121 : __shared_ptr(_Sp_make_shared_tag __tag, const _Alloc& __a,
1122 : _Args&&... __args)
1123 : : _M_ptr(), _M_refcount()
1124 : {
1125 : typedef typename allocator_traits<_Alloc>::template
1126 : rebind_traits<typename std::remove_cv<_Tp>::type> __traits;
1127 : _Deleter<typename __traits::allocator_type> __del = { __a };
1128 : auto __guard = std::__allocate_guarded(__del._M_alloc);
1129 : auto __ptr = __guard.get();
1130 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
1131 : // 2070. allocate_shared should use allocator_traits<A>::construct
1132 : __traits::construct(__del._M_alloc, __ptr,
1133 : std::forward<_Args>(__args)...);
1134 : __guard = nullptr;
1135 : __shared_count<_Lp> __count(__ptr, __del, __del._M_alloc);
1136 : _M_refcount._M_swap(__count);
1137 : _M_ptr = __ptr;
1138 : __enable_shared_from_this_helper(_M_refcount, _M_ptr, _M_ptr);
1139 : }
1140 : #endif
1141 :
1142 : template<typename _Tp1, _Lock_policy _Lp1, typename _Alloc,
1143 : typename... _Args>
1144 : friend __shared_ptr<_Tp1, _Lp1>
1145 : __allocate_shared(const _Alloc& __a, _Args&&... __args);
1146 :
1147 : // This constructor is used by __weak_ptr::lock() and
1148 : // shared_ptr::shared_ptr(const weak_ptr&, std::nothrow_t).
1149 29525 : __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t)
1150 29525 : : _M_refcount(__r._M_refcount, std::nothrow)
1151 : {
1152 29525 : _M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr;
1153 29525 : }
1154 :
1155 : friend class __weak_ptr<_Tp, _Lp>;
1156 :
1157 : private:
1158 : void*
1159 : _M_get_deleter(const std::type_info& __ti) const noexcept
1160 : { return _M_refcount._M_get_deleter(__ti); }
1161 :
1162 : template<typename _Tp1>
1163 : static _Tp1*
1164 : _S_raw_ptr(_Tp1* __ptr)
1165 : { return __ptr; }
1166 :
1167 : template<typename _Tp1>
1168 : static auto
1169 : _S_raw_ptr(_Tp1 __ptr) -> decltype(std::__addressof(*__ptr))
1170 : { return std::__addressof(*__ptr); }
1171 :
1172 : template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1173 : template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1174 :
1175 : template<typename _Del, typename _Tp1, _Lock_policy _Lp1>
1176 : friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&) noexcept;
1177 :
1178 : _Tp* _M_ptr; // Contained pointer.
1179 : __shared_count<_Lp> _M_refcount; // Reference counter.
1180 : };
1181 :
1182 :
1183 : // 20.7.2.2.7 shared_ptr comparisons
1184 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1185 : inline bool
1186 : operator==(const __shared_ptr<_Tp1, _Lp>& __a,
1187 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1188 : { return __a.get() == __b.get(); }
1189 :
1190 : template<typename _Tp, _Lock_policy _Lp>
1191 : inline bool
1192 : operator==(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1193 : { return !__a; }
1194 :
1195 : template<typename _Tp, _Lock_policy _Lp>
1196 : inline bool
1197 : operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1198 : { return !__a; }
1199 :
1200 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1201 : inline bool
1202 : operator!=(const __shared_ptr<_Tp1, _Lp>& __a,
1203 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1204 : { return __a.get() != __b.get(); }
1205 :
1206 : template<typename _Tp, _Lock_policy _Lp>
1207 : inline bool
1208 : operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1209 : { return (bool)__a; }
1210 :
1211 : template<typename _Tp, _Lock_policy _Lp>
1212 : inline bool
1213 : operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1214 : { return (bool)__a; }
1215 :
1216 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1217 : inline bool
1218 : operator<(const __shared_ptr<_Tp1, _Lp>& __a,
1219 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1220 : {
1221 : typedef typename std::common_type<_Tp1*, _Tp2*>::type _CT;
1222 : return std::less<_CT>()(__a.get(), __b.get());
1223 : }
1224 :
1225 : template<typename _Tp, _Lock_policy _Lp>
1226 : inline bool
1227 : operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1228 : { return std::less<_Tp*>()(__a.get(), nullptr); }
1229 :
1230 : template<typename _Tp, _Lock_policy _Lp>
1231 : inline bool
1232 : operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1233 : { return std::less<_Tp*>()(nullptr, __a.get()); }
1234 :
1235 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1236 : inline bool
1237 : operator<=(const __shared_ptr<_Tp1, _Lp>& __a,
1238 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1239 : { return !(__b < __a); }
1240 :
1241 : template<typename _Tp, _Lock_policy _Lp>
1242 : inline bool
1243 : operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1244 : { return !(nullptr < __a); }
1245 :
1246 : template<typename _Tp, _Lock_policy _Lp>
1247 : inline bool
1248 : operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1249 : { return !(__a < nullptr); }
1250 :
1251 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1252 : inline bool
1253 : operator>(const __shared_ptr<_Tp1, _Lp>& __a,
1254 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1255 : { return (__b < __a); }
1256 :
1257 : template<typename _Tp, _Lock_policy _Lp>
1258 : inline bool
1259 : operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1260 : { return std::less<_Tp*>()(nullptr, __a.get()); }
1261 :
1262 : template<typename _Tp, _Lock_policy _Lp>
1263 : inline bool
1264 : operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1265 : { return std::less<_Tp*>()(__a.get(), nullptr); }
1266 :
1267 : template<typename _Tp1, typename _Tp2, _Lock_policy _Lp>
1268 : inline bool
1269 : operator>=(const __shared_ptr<_Tp1, _Lp>& __a,
1270 : const __shared_ptr<_Tp2, _Lp>& __b) noexcept
1271 : { return !(__a < __b); }
1272 :
1273 : template<typename _Tp, _Lock_policy _Lp>
1274 : inline bool
1275 : operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept
1276 : { return !(__a < nullptr); }
1277 :
1278 : template<typename _Tp, _Lock_policy _Lp>
1279 : inline bool
1280 : operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept
1281 : { return !(nullptr < __a); }
1282 :
1283 : template<typename _Sp>
1284 : struct _Sp_less : public binary_function<_Sp, _Sp, bool>
1285 : {
1286 : bool
1287 : operator()(const _Sp& __lhs, const _Sp& __rhs) const noexcept
1288 : {
1289 : typedef typename _Sp::element_type element_type;
1290 : return std::less<element_type*>()(__lhs.get(), __rhs.get());
1291 : }
1292 : };
1293 :
1294 : template<typename _Tp, _Lock_policy _Lp>
1295 : struct less<__shared_ptr<_Tp, _Lp>>
1296 : : public _Sp_less<__shared_ptr<_Tp, _Lp>>
1297 : { };
1298 :
1299 : // 20.7.2.2.8 shared_ptr specialized algorithms.
1300 : template<typename _Tp, _Lock_policy _Lp>
1301 : inline void
1302 : swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) noexcept
1303 : { __a.swap(__b); }
1304 :
1305 : // 20.7.2.2.9 shared_ptr casts
1306 :
1307 : // The seemingly equivalent code:
1308 : // shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get()))
1309 : // will eventually result in undefined behaviour, attempting to
1310 : // delete the same object twice.
1311 : /// static_pointer_cast
1312 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1313 : inline __shared_ptr<_Tp, _Lp>
1314 : static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1315 : { return __shared_ptr<_Tp, _Lp>(__r, static_cast<_Tp*>(__r.get())); }
1316 :
1317 : // The seemingly equivalent code:
1318 : // shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get()))
1319 : // will eventually result in undefined behaviour, attempting to
1320 : // delete the same object twice.
1321 : /// const_pointer_cast
1322 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1323 : inline __shared_ptr<_Tp, _Lp>
1324 : const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1325 : { return __shared_ptr<_Tp, _Lp>(__r, const_cast<_Tp*>(__r.get())); }
1326 :
1327 : // The seemingly equivalent code:
1328 : // shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get()))
1329 : // will eventually result in undefined behaviour, attempting to
1330 : // delete the same object twice.
1331 : /// dynamic_pointer_cast
1332 : template<typename _Tp, typename _Tp1, _Lock_policy _Lp>
1333 : inline __shared_ptr<_Tp, _Lp>
1334 : dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1335 : {
1336 : if (_Tp* __p = dynamic_cast<_Tp*>(__r.get()))
1337 : return __shared_ptr<_Tp, _Lp>(__r, __p);
1338 : return __shared_ptr<_Tp, _Lp>();
1339 : }
1340 :
1341 :
1342 : template<typename _Tp, _Lock_policy _Lp>
1343 : class __weak_ptr
1344 : {
1345 : template<typename _Ptr>
1346 : using _Convertible
1347 : = typename enable_if<is_convertible<_Ptr, _Tp*>::value>::type;
1348 :
1349 : public:
1350 : typedef _Tp element_type;
1351 :
1352 138 : constexpr __weak_ptr() noexcept
1353 138 : : _M_ptr(nullptr), _M_refcount()
1354 138 : { }
1355 :
1356 19644 : __weak_ptr(const __weak_ptr&) noexcept = default;
1357 :
1358 57881 : ~__weak_ptr() = default;
1359 :
1360 : // The "obvious" converting constructor implementation:
1361 : //
1362 : // template<typename _Tp1>
1363 : // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r)
1364 : // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws
1365 : // { }
1366 : //
1367 : // has a serious problem.
1368 : //
1369 : // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr)
1370 : // conversion may require access to *__r._M_ptr (virtual inheritance).
1371 : //
1372 : // It is not possible to avoid spurious access violations since
1373 : // in multithreaded programs __r._M_ptr may be invalidated at any point.
1374 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
1375 : __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r) noexcept
1376 : : _M_refcount(__r._M_refcount)
1377 : { _M_ptr = __r.lock().get(); }
1378 :
1379 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
1380 38357 : __weak_ptr(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1381 38357 : : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount)
1382 38357 : { }
1383 :
1384 4 : __weak_ptr(__weak_ptr&& __r) noexcept
1385 4 : : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount))
1386 4 : { __r._M_ptr = nullptr; }
1387 :
1388 : template<typename _Tp1, typename = _Convertible<_Tp1*>>
1389 : __weak_ptr(__weak_ptr<_Tp1, _Lp>&& __r) noexcept
1390 : : _M_ptr(__r.lock().get()), _M_refcount(std::move(__r._M_refcount))
1391 : { __r._M_ptr = nullptr; }
1392 :
1393 : __weak_ptr&
1394 : operator=(const __weak_ptr& __r) noexcept = default;
1395 :
1396 : template<typename _Tp1>
1397 : __weak_ptr&
1398 : operator=(const __weak_ptr<_Tp1, _Lp>& __r) noexcept
1399 : {
1400 : _M_ptr = __r.lock().get();
1401 : _M_refcount = __r._M_refcount;
1402 : return *this;
1403 : }
1404 :
1405 : template<typename _Tp1>
1406 : __weak_ptr&
1407 : operator=(const __shared_ptr<_Tp1, _Lp>& __r) noexcept
1408 : {
1409 : _M_ptr = __r._M_ptr;
1410 : _M_refcount = __r._M_refcount;
1411 : return *this;
1412 : }
1413 :
1414 : __weak_ptr&
1415 : operator=(__weak_ptr&& __r) noexcept
1416 : {
1417 : _M_ptr = __r._M_ptr;
1418 : _M_refcount = std::move(__r._M_refcount);
1419 : __r._M_ptr = nullptr;
1420 : return *this;
1421 : }
1422 :
1423 : template<typename _Tp1>
1424 : __weak_ptr&
1425 : operator=(__weak_ptr<_Tp1, _Lp>&& __r) noexcept
1426 : {
1427 : _M_ptr = __r.lock().get();
1428 : _M_refcount = std::move(__r._M_refcount);
1429 : __r._M_ptr = nullptr;
1430 : return *this;
1431 : }
1432 :
1433 : __shared_ptr<_Tp, _Lp>
1434 : lock() const noexcept
1435 : { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); }
1436 :
1437 : long
1438 138 : use_count() const noexcept
1439 138 : { return _M_refcount._M_get_use_count(); }
1440 :
1441 : bool
1442 85082 : expired() const noexcept
1443 85082 : { return _M_refcount._M_get_use_count() == 0; }
1444 :
1445 : template<typename _Tp1>
1446 : bool
1447 : owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const
1448 : { return _M_refcount._M_less(__rhs._M_refcount); }
1449 :
1450 : template<typename _Tp1>
1451 : bool
1452 : owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const
1453 : { return _M_refcount._M_less(__rhs._M_refcount); }
1454 :
1455 : void
1456 : reset() noexcept
1457 : { __weak_ptr().swap(*this); }
1458 :
1459 : void
1460 : swap(__weak_ptr& __s) noexcept
1461 : {
1462 : std::swap(_M_ptr, __s._M_ptr);
1463 : _M_refcount._M_swap(__s._M_refcount);
1464 : }
1465 :
1466 : private:
1467 : // Used by __enable_shared_from_this.
1468 : void
1469 138 : _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept
1470 : {
1471 138 : if (use_count() == 0)
1472 : {
1473 138 : _M_ptr = __ptr;
1474 138 : _M_refcount = __refcount;
1475 : }
1476 138 : }
1477 :
1478 : template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr;
1479 : template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr;
1480 : friend class __enable_shared_from_this<_Tp, _Lp>;
1481 : friend class enable_shared_from_this<_Tp>;
1482 :
1483 : _Tp* _M_ptr; // Contained pointer.
1484 : __weak_count<_Lp> _M_refcount; // Reference counter.
1485 : };
1486 :
1487 : // 20.7.2.3.6 weak_ptr specialized algorithms.
1488 : template<typename _Tp, _Lock_policy _Lp>
1489 : inline void
1490 : swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept
1491 : { __a.swap(__b); }
1492 :
1493 : template<typename _Tp, typename _Tp1>
1494 : struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool>
1495 : {
1496 : bool
1497 : operator()(const _Tp& __lhs, const _Tp& __rhs) const
1498 : { return __lhs.owner_before(__rhs); }
1499 :
1500 : bool
1501 : operator()(const _Tp& __lhs, const _Tp1& __rhs) const
1502 : { return __lhs.owner_before(__rhs); }
1503 :
1504 : bool
1505 : operator()(const _Tp1& __lhs, const _Tp& __rhs) const
1506 : { return __lhs.owner_before(__rhs); }
1507 : };
1508 :
1509 : template<typename _Tp, _Lock_policy _Lp>
1510 : struct owner_less<__shared_ptr<_Tp, _Lp>>
1511 : : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>
1512 : { };
1513 :
1514 : template<typename _Tp, _Lock_policy _Lp>
1515 : struct owner_less<__weak_ptr<_Tp, _Lp>>
1516 : : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>>
1517 : { };
1518 :
1519 :
1520 : template<typename _Tp, _Lock_policy _Lp>
1521 : class __enable_shared_from_this
1522 : {
1523 : protected:
1524 : constexpr __enable_shared_from_this() noexcept { }
1525 :
1526 : __enable_shared_from_this(const __enable_shared_from_this&) noexcept { }
1527 :
1528 : __enable_shared_from_this&
1529 : operator=(const __enable_shared_from_this&) noexcept
1530 : { return *this; }
1531 :
1532 : ~__enable_shared_from_this() { }
1533 :
1534 : public:
1535 : __shared_ptr<_Tp, _Lp>
1536 : shared_from_this()
1537 : { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); }
1538 :
1539 : __shared_ptr<const _Tp, _Lp>
1540 : shared_from_this() const
1541 : { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); }
1542 :
1543 : private:
1544 : template<typename _Tp1>
1545 : void
1546 : _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept
1547 : { _M_weak_this._M_assign(__p, __n); }
1548 :
1549 : template<_Lock_policy _Lp1, typename _Tp1, typename _Tp2>
1550 : friend void
1551 : __enable_shared_from_this_helper(const __shared_count<_Lp1>&,
1552 : const __enable_shared_from_this<_Tp1,
1553 : _Lp1>*, const _Tp2*) noexcept;
1554 :
1555 : mutable __weak_ptr<_Tp, _Lp> _M_weak_this;
1556 : };
1557 :
1558 : template<_Lock_policy _Lp1, typename _Tp1, typename _Tp2>
1559 : inline void
1560 : __enable_shared_from_this_helper(const __shared_count<_Lp1>& __pn,
1561 : const __enable_shared_from_this<_Tp1,
1562 : _Lp1>* __pe,
1563 : const _Tp2* __px) noexcept
1564 : {
1565 : if (__pe != nullptr)
1566 : __pe->_M_weak_assign(const_cast<_Tp2*>(__px), __pn);
1567 : }
1568 :
1569 : template<typename _Tp, _Lock_policy _Lp, typename _Alloc, typename... _Args>
1570 : inline __shared_ptr<_Tp, _Lp>
1571 : __allocate_shared(const _Alloc& __a, _Args&&... __args)
1572 : {
1573 : return __shared_ptr<_Tp, _Lp>(_Sp_make_shared_tag(), __a,
1574 : std::forward<_Args>(__args)...);
1575 : }
1576 :
1577 : template<typename _Tp, _Lock_policy _Lp, typename... _Args>
1578 : inline __shared_ptr<_Tp, _Lp>
1579 : __make_shared(_Args&&... __args)
1580 : {
1581 : typedef typename std::remove_const<_Tp>::type _Tp_nc;
1582 : return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(),
1583 : std::forward<_Args>(__args)...);
1584 : }
1585 :
1586 : /// std::hash specialization for __shared_ptr.
1587 : template<typename _Tp, _Lock_policy _Lp>
1588 : struct hash<__shared_ptr<_Tp, _Lp>>
1589 : : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>>
1590 : {
1591 : size_t
1592 : operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept
1593 : { return std::hash<_Tp*>()(__s.get()); }
1594 : };
1595 :
1596 : _GLIBCXX_END_NAMESPACE_VERSION
1597 : } // namespace
1598 :
1599 : #endif // _SHARED_PTR_BASE_H
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