1 | // shared_ptr and weak_ptr implementation details -*- C++ -*- |
2 | |
3 | // Copyright (C) 2007-2021 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/allocator.h> |
55 | #include <bits/exception_defines.h> |
56 | #include <bits/functional_hash.h> |
57 | #include <bits/refwrap.h> |
58 | #include <bits/stl_function.h> // std::less |
59 | #include <bits/unique_ptr.h> |
60 | #include <ext/aligned_buffer.h> |
61 | #include <ext/atomicity.h> |
62 | #include <ext/concurrence.h> |
63 | #if __cplusplus > 201703L |
64 | # include <compare> |
65 | #endif |
66 | |
67 | namespace std _GLIBCXX_VISIBILITY(default) |
68 | { |
69 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
70 | |
71 | #if _GLIBCXX_USE_DEPRECATED |
72 | #pragma GCC diagnostic push |
73 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
74 | template<typename> class auto_ptr; |
75 | #pragma GCC diagnostic pop |
76 | #endif |
77 | |
78 | /** |
79 | * @brief Exception possibly thrown by @c shared_ptr. |
80 | * @ingroup exceptions |
81 | */ |
82 | class bad_weak_ptr : public std::exception |
83 | { |
84 | public: |
85 | virtual char const* what() const noexcept; |
86 | |
87 | virtual ~bad_weak_ptr() noexcept; |
88 | }; |
89 | |
90 | // Substitute for bad_weak_ptr object in the case of -fno-exceptions. |
91 | inline void |
92 | __throw_bad_weak_ptr() |
93 | { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); } |
94 | |
95 | using __gnu_cxx::_Lock_policy; |
96 | using __gnu_cxx::__default_lock_policy; |
97 | using __gnu_cxx::_S_single; |
98 | using __gnu_cxx::_S_mutex; |
99 | using __gnu_cxx::_S_atomic; |
100 | |
101 | // Empty helper class except when the template argument is _S_mutex. |
102 | template<_Lock_policy _Lp> |
103 | class _Mutex_base |
104 | { |
105 | protected: |
106 | // The atomic policy uses fully-fenced builtins, single doesn't care. |
107 | enum { _S_need_barriers = 0 }; |
108 | }; |
109 | |
110 | template<> |
111 | class _Mutex_base<_S_mutex> |
112 | : public __gnu_cxx::__mutex |
113 | { |
114 | protected: |
115 | // This policy is used when atomic builtins are not available. |
116 | // The replacement atomic operations might not have the necessary |
117 | // memory barriers. |
118 | enum { _S_need_barriers = 1 }; |
119 | }; |
120 | |
121 | template<_Lock_policy _Lp = __default_lock_policy> |
122 | class _Sp_counted_base |
123 | : public _Mutex_base<_Lp> |
124 | { |
125 | public: |
126 | _Sp_counted_base() noexcept |
127 | : _M_use_count(1), _M_weak_count(1) { } |
128 | |
129 | virtual |
130 | ~_Sp_counted_base() noexcept |
131 | { } |
132 | |
133 | // Called when _M_use_count drops to zero, to release the resources |
134 | // managed by *this. |
135 | virtual void |
136 | _M_dispose() noexcept = 0; |
137 | |
138 | // Called when _M_weak_count drops to zero. |
139 | virtual void |
140 | _M_destroy() noexcept |
141 | { delete this; } |
142 | |
143 | virtual void* |
144 | _M_get_deleter(const std::type_info&) noexcept = 0; |
145 | |
146 | void |
147 | _M_add_ref_copy() |
148 | { __gnu_cxx::__atomic_add_dispatch(mem: &_M_use_count, val: 1); } |
149 | |
150 | void |
151 | _M_add_ref_lock() |
152 | { |
153 | if (!_M_add_ref_lock_nothrow()) |
154 | __throw_bad_weak_ptr(); |
155 | } |
156 | |
157 | bool |
158 | _M_add_ref_lock_nothrow() noexcept; |
159 | |
160 | void |
161 | _M_release() noexcept |
162 | { |
163 | // Be race-detector-friendly. For more info see bits/c++config. |
164 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count); |
165 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_use_count, val: -1) == 1) |
166 | { |
167 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count); |
168 | _M_dispose(); |
169 | // There must be a memory barrier between dispose() and destroy() |
170 | // to ensure that the effects of dispose() are observed in the |
171 | // thread that runs destroy(). |
172 | // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html |
173 | if (_Mutex_base<_Lp>::_S_need_barriers) |
174 | { |
175 | __atomic_thread_fence (__ATOMIC_ACQ_REL); |
176 | } |
177 | |
178 | // Be race-detector-friendly. For more info see bits/c++config. |
179 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); |
180 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_weak_count, |
181 | val: -1) == 1) |
182 | { |
183 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); |
184 | _M_destroy(); |
185 | } |
186 | } |
187 | } |
188 | |
189 | void |
190 | _M_weak_add_ref() noexcept |
191 | { __gnu_cxx::__atomic_add_dispatch(mem: &_M_weak_count, val: 1); } |
192 | |
193 | void |
194 | _M_weak_release() noexcept |
195 | { |
196 | // Be race-detector-friendly. For more info see bits/c++config. |
197 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); |
198 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_weak_count, val: -1) == 1) |
199 | { |
200 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); |
201 | if (_Mutex_base<_Lp>::_S_need_barriers) |
202 | { |
203 | // See _M_release(), |
204 | // destroy() must observe results of dispose() |
205 | __atomic_thread_fence (__ATOMIC_ACQ_REL); |
206 | } |
207 | _M_destroy(); |
208 | } |
209 | } |
210 | |
211 | long |
212 | _M_get_use_count() const noexcept |
213 | { |
214 | // No memory barrier is used here so there is no synchronization |
215 | // with other threads. |
216 | return __atomic_load_n(&_M_use_count, __ATOMIC_RELAXED); |
217 | } |
218 | |
219 | private: |
220 | _Sp_counted_base(_Sp_counted_base const&) = delete; |
221 | _Sp_counted_base& operator=(_Sp_counted_base const&) = delete; |
222 | |
223 | _Atomic_word _M_use_count; // #shared |
224 | _Atomic_word _M_weak_count; // #weak + (#shared != 0) |
225 | }; |
226 | |
227 | template<> |
228 | inline bool |
229 | _Sp_counted_base<_S_single>:: |
230 | _M_add_ref_lock_nothrow() noexcept |
231 | { |
232 | if (_M_use_count == 0) |
233 | return false; |
234 | ++_M_use_count; |
235 | return true; |
236 | } |
237 | |
238 | template<> |
239 | inline bool |
240 | _Sp_counted_base<_S_mutex>:: |
241 | _M_add_ref_lock_nothrow() noexcept |
242 | { |
243 | __gnu_cxx::__scoped_lock sentry(*this); |
244 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_use_count, val: 1) == 0) |
245 | { |
246 | _M_use_count = 0; |
247 | return false; |
248 | } |
249 | return true; |
250 | } |
251 | |
252 | template<> |
253 | inline bool |
254 | _Sp_counted_base<_S_atomic>:: |
255 | _M_add_ref_lock_nothrow() noexcept |
256 | { |
257 | // Perform lock-free add-if-not-zero operation. |
258 | _Atomic_word __count = _M_get_use_count(); |
259 | do |
260 | { |
261 | if (__count == 0) |
262 | return false; |
263 | // Replace the current counter value with the old value + 1, as |
264 | // long as it's not changed meanwhile. |
265 | } |
266 | while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1, |
267 | true, __ATOMIC_ACQ_REL, |
268 | __ATOMIC_RELAXED)); |
269 | return true; |
270 | } |
271 | |
272 | template<> |
273 | inline void |
274 | _Sp_counted_base<_S_single>::_M_add_ref_copy() |
275 | { ++_M_use_count; } |
276 | |
277 | template<> |
278 | inline void |
279 | _Sp_counted_base<_S_single>::_M_release() noexcept |
280 | { |
281 | if (--_M_use_count == 0) |
282 | { |
283 | _M_dispose(); |
284 | if (--_M_weak_count == 0) |
285 | _M_destroy(); |
286 | } |
287 | } |
288 | |
289 | template<> |
290 | inline void |
291 | _Sp_counted_base<_S_single>::_M_weak_add_ref() noexcept |
292 | { ++_M_weak_count; } |
293 | |
294 | template<> |
295 | inline void |
296 | _Sp_counted_base<_S_single>::_M_weak_release() noexcept |
297 | { |
298 | if (--_M_weak_count == 0) |
299 | _M_destroy(); |
300 | } |
301 | |
302 | template<> |
303 | inline long |
304 | _Sp_counted_base<_S_single>::_M_get_use_count() const noexcept |
305 | { return _M_use_count; } |
306 | |
307 | |
308 | // Forward declarations. |
309 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> |
310 | class __shared_ptr; |
311 | |
312 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> |
313 | class __weak_ptr; |
314 | |
315 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> |
316 | class __enable_shared_from_this; |
317 | |
318 | template<typename _Tp> |
319 | class shared_ptr; |
320 | |
321 | template<typename _Tp> |
322 | class weak_ptr; |
323 | |
324 | template<typename _Tp> |
325 | struct owner_less; |
326 | |
327 | template<typename _Tp> |
328 | class enable_shared_from_this; |
329 | |
330 | template<_Lock_policy _Lp = __default_lock_policy> |
331 | class __weak_count; |
332 | |
333 | template<_Lock_policy _Lp = __default_lock_policy> |
334 | class __shared_count; |
335 | |
336 | |
337 | // Counted ptr with no deleter or allocator support |
338 | template<typename _Ptr, _Lock_policy _Lp> |
339 | class _Sp_counted_ptr final : public _Sp_counted_base<_Lp> |
340 | { |
341 | public: |
342 | explicit |
343 | _Sp_counted_ptr(_Ptr __p) noexcept |
344 | : _M_ptr(__p) { } |
345 | |
346 | virtual void |
347 | _M_dispose() noexcept |
348 | { delete _M_ptr; } |
349 | |
350 | virtual void |
351 | _M_destroy() noexcept |
352 | { delete this; } |
353 | |
354 | virtual void* |
355 | _M_get_deleter(const std::type_info&) noexcept |
356 | { return nullptr; } |
357 | |
358 | _Sp_counted_ptr(const _Sp_counted_ptr&) = delete; |
359 | _Sp_counted_ptr& operator=(const _Sp_counted_ptr&) = delete; |
360 | |
361 | private: |
362 | _Ptr _M_ptr; |
363 | }; |
364 | |
365 | template<> |
366 | inline void |
367 | _Sp_counted_ptr<nullptr_t, _S_single>::_M_dispose() noexcept { } |
368 | |
369 | template<> |
370 | inline void |
371 | _Sp_counted_ptr<nullptr_t, _S_mutex>::_M_dispose() noexcept { } |
372 | |
373 | template<> |
374 | inline void |
375 | _Sp_counted_ptr<nullptr_t, _S_atomic>::_M_dispose() noexcept { } |
376 | |
377 | template<int _Nm, typename _Tp, |
378 | bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)> |
379 | struct _Sp_ebo_helper; |
380 | |
381 | /// Specialization using EBO. |
382 | template<int _Nm, typename _Tp> |
383 | struct _Sp_ebo_helper<_Nm, _Tp, true> : private _Tp |
384 | { |
385 | explicit _Sp_ebo_helper(const _Tp& __tp) : _Tp(__tp) { } |
386 | explicit _Sp_ebo_helper(_Tp&& __tp) : _Tp(std::move(__tp)) { } |
387 | |
388 | static _Tp& |
389 | _S_get(_Sp_ebo_helper& __eboh) { return static_cast<_Tp&>(__eboh); } |
390 | }; |
391 | |
392 | /// Specialization not using EBO. |
393 | template<int _Nm, typename _Tp> |
394 | struct _Sp_ebo_helper<_Nm, _Tp, false> |
395 | { |
396 | explicit _Sp_ebo_helper(const _Tp& __tp) : _M_tp(__tp) { } |
397 | explicit _Sp_ebo_helper(_Tp&& __tp) : _M_tp(std::move(__tp)) { } |
398 | |
399 | static _Tp& |
400 | _S_get(_Sp_ebo_helper& __eboh) |
401 | { return __eboh._M_tp; } |
402 | |
403 | private: |
404 | _Tp _M_tp; |
405 | }; |
406 | |
407 | // Support for custom deleter and/or allocator |
408 | template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp> |
409 | class _Sp_counted_deleter final : public _Sp_counted_base<_Lp> |
410 | { |
411 | class _Impl : _Sp_ebo_helper<0, _Deleter>, _Sp_ebo_helper<1, _Alloc> |
412 | { |
413 | typedef _Sp_ebo_helper<0, _Deleter> _Del_base; |
414 | typedef _Sp_ebo_helper<1, _Alloc> _Alloc_base; |
415 | |
416 | public: |
417 | _Impl(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept |
418 | : _Del_base(std::move(__d)), _Alloc_base(__a), _M_ptr(__p) |
419 | { } |
420 | |
421 | _Deleter& _M_del() noexcept { return _Del_base::_S_get(*this); } |
422 | _Alloc& _M_alloc() noexcept { return _Alloc_base::_S_get(*this); } |
423 | |
424 | _Ptr _M_ptr; |
425 | }; |
426 | |
427 | public: |
428 | using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_deleter>; |
429 | |
430 | // __d(__p) must not throw. |
431 | _Sp_counted_deleter(_Ptr __p, _Deleter __d) noexcept |
432 | : _M_impl(__p, std::move(__d), _Alloc()) { } |
433 | |
434 | // __d(__p) must not throw. |
435 | _Sp_counted_deleter(_Ptr __p, _Deleter __d, const _Alloc& __a) noexcept |
436 | : _M_impl(__p, std::move(__d), __a) { } |
437 | |
438 | ~_Sp_counted_deleter() noexcept { } |
439 | |
440 | virtual void |
441 | _M_dispose() noexcept |
442 | { _M_impl._M_del()(_M_impl._M_ptr); } |
443 | |
444 | virtual void |
445 | _M_destroy() noexcept |
446 | { |
447 | __allocator_type __a(_M_impl._M_alloc()); |
448 | __allocated_ptr<__allocator_type> __guard_ptr{ __a, this }; |
449 | this->~_Sp_counted_deleter(); |
450 | } |
451 | |
452 | virtual void* |
453 | _M_get_deleter(const type_info& __ti [[__gnu__::__unused__]]) noexcept |
454 | { |
455 | #if __cpp_rtti |
456 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
457 | // 2400. shared_ptr's get_deleter() should use addressof() |
458 | return __ti == typeid(_Deleter) |
459 | ? std::__addressof(_M_impl._M_del()) |
460 | : nullptr; |
461 | #else |
462 | return nullptr; |
463 | #endif |
464 | } |
465 | |
466 | private: |
467 | _Impl _M_impl; |
468 | }; |
469 | |
470 | // helpers for make_shared / allocate_shared |
471 | |
472 | struct _Sp_make_shared_tag |
473 | { |
474 | private: |
475 | template<typename _Tp, typename _Alloc, _Lock_policy _Lp> |
476 | friend class _Sp_counted_ptr_inplace; |
477 | |
478 | static const type_info& |
479 | _S_ti() noexcept _GLIBCXX_VISIBILITY(default) |
480 | { |
481 | alignas(type_info) static constexpr char __tag[sizeof(type_info)] = { }; |
482 | return reinterpret_cast<const type_info&>(__tag); |
483 | } |
484 | |
485 | static bool _S_eq(const type_info&) noexcept; |
486 | }; |
487 | |
488 | template<typename _Alloc> |
489 | struct _Sp_alloc_shared_tag |
490 | { |
491 | const _Alloc& _M_a; |
492 | }; |
493 | |
494 | template<typename _Tp, typename _Alloc, _Lock_policy _Lp> |
495 | class _Sp_counted_ptr_inplace final : public _Sp_counted_base<_Lp> |
496 | { |
497 | class _Impl : _Sp_ebo_helper<0, _Alloc> |
498 | { |
499 | typedef _Sp_ebo_helper<0, _Alloc> _A_base; |
500 | |
501 | public: |
502 | explicit _Impl(_Alloc __a) noexcept : _A_base(__a) { } |
503 | |
504 | _Alloc& _M_alloc() noexcept { return _A_base::_S_get(*this); } |
505 | |
506 | __gnu_cxx::__aligned_buffer<_Tp> _M_storage; |
507 | }; |
508 | |
509 | public: |
510 | using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>; |
511 | |
512 | // Alloc parameter is not a reference so doesn't alias anything in __args |
513 | template<typename... _Args> |
514 | _Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args) |
515 | : _M_impl(__a) |
516 | { |
517 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
518 | // 2070. allocate_shared should use allocator_traits<A>::construct |
519 | allocator_traits<_Alloc>::construct(__a, _M_ptr(), |
520 | std::forward<_Args>(__args)...); // might throw |
521 | } |
522 | |
523 | ~_Sp_counted_ptr_inplace() noexcept { } |
524 | |
525 | virtual void |
526 | _M_dispose() noexcept |
527 | { |
528 | allocator_traits<_Alloc>::destroy(_M_impl._M_alloc(), _M_ptr()); |
529 | } |
530 | |
531 | // Override because the allocator needs to know the dynamic type |
532 | virtual void |
533 | _M_destroy() noexcept |
534 | { |
535 | __allocator_type __a(_M_impl._M_alloc()); |
536 | __allocated_ptr<__allocator_type> __guard_ptr{ __a, this }; |
537 | this->~_Sp_counted_ptr_inplace(); |
538 | } |
539 | |
540 | private: |
541 | friend class __shared_count<_Lp>; // To be able to call _M_ptr(). |
542 | |
543 | // No longer used, but code compiled against old libstdc++ headers |
544 | // might still call it from __shared_ptr ctor to get the pointer out. |
545 | virtual void* |
546 | _M_get_deleter(const std::type_info& __ti) noexcept override |
547 | { |
548 | auto __ptr = const_cast<typename remove_cv<_Tp>::type*>(_M_ptr()); |
549 | // Check for the fake type_info first, so we don't try to access it |
550 | // as a real type_info object. Otherwise, check if it's the real |
551 | // type_info for this class. With RTTI enabled we can check directly, |
552 | // or call a library function to do it. |
553 | if (&__ti == &_Sp_make_shared_tag::_S_ti() |
554 | || |
555 | #if __cpp_rtti |
556 | __ti == typeid(_Sp_make_shared_tag) |
557 | #else |
558 | _Sp_make_shared_tag::_S_eq(__ti) |
559 | #endif |
560 | ) |
561 | return __ptr; |
562 | return nullptr; |
563 | } |
564 | |
565 | _Tp* _M_ptr() noexcept { return _M_impl._M_storage._M_ptr(); } |
566 | |
567 | _Impl _M_impl; |
568 | }; |
569 | |
570 | // The default deleter for shared_ptr<T[]> and shared_ptr<T[N]>. |
571 | struct __sp_array_delete |
572 | { |
573 | template<typename _Yp> |
574 | void operator()(_Yp* __p) const { delete[] __p; } |
575 | }; |
576 | |
577 | template<_Lock_policy _Lp> |
578 | class __shared_count |
579 | { |
580 | template<typename _Tp> |
581 | struct __not_alloc_shared_tag { using type = void; }; |
582 | |
583 | template<typename _Tp> |
584 | struct __not_alloc_shared_tag<_Sp_alloc_shared_tag<_Tp>> { }; |
585 | |
586 | public: |
587 | constexpr __shared_count() noexcept : _M_pi(0) |
588 | { } |
589 | |
590 | template<typename _Ptr> |
591 | explicit |
592 | __shared_count(_Ptr __p) : _M_pi(0) |
593 | { |
594 | __try |
595 | { |
596 | _M_pi = new _Sp_counted_ptr<_Ptr, _Lp>(__p); |
597 | } |
598 | __catch(...) |
599 | { |
600 | delete __p; |
601 | __throw_exception_again; |
602 | } |
603 | } |
604 | |
605 | template<typename _Ptr> |
606 | __shared_count(_Ptr __p, /* is_array = */ false_type) |
607 | : __shared_count(__p) |
608 | { } |
609 | |
610 | template<typename _Ptr> |
611 | __shared_count(_Ptr __p, /* is_array = */ true_type) |
612 | : __shared_count(__p, __sp_array_delete{}, allocator<void>()) |
613 | { } |
614 | |
615 | template<typename _Ptr, typename _Deleter, |
616 | typename = typename __not_alloc_shared_tag<_Deleter>::type> |
617 | __shared_count(_Ptr __p, _Deleter __d) |
618 | : __shared_count(__p, std::move(__d), allocator<void>()) |
619 | { } |
620 | |
621 | template<typename _Ptr, typename _Deleter, typename _Alloc, |
622 | typename = typename __not_alloc_shared_tag<_Deleter>::type> |
623 | __shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0) |
624 | { |
625 | typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type; |
626 | __try |
627 | { |
628 | typename _Sp_cd_type::__allocator_type __a2(__a); |
629 | auto __guard = std::__allocate_guarded(__a2); |
630 | _Sp_cd_type* __mem = __guard.get(); |
631 | ::new (__mem) _Sp_cd_type(__p, std::move(__d), std::move(__a)); |
632 | _M_pi = __mem; |
633 | __guard = nullptr; |
634 | } |
635 | __catch(...) |
636 | { |
637 | __d(__p); // Call _Deleter on __p. |
638 | __throw_exception_again; |
639 | } |
640 | } |
641 | |
642 | template<typename _Tp, typename _Alloc, typename... _Args> |
643 | __shared_count(_Tp*& __p, _Sp_alloc_shared_tag<_Alloc> __a, |
644 | _Args&&... __args) |
645 | { |
646 | typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type; |
647 | typename _Sp_cp_type::__allocator_type __a2(__a._M_a); |
648 | auto __guard = std::__allocate_guarded(__a2); |
649 | _Sp_cp_type* __mem = __guard.get(); |
650 | auto __pi = ::new (__mem) |
651 | _Sp_cp_type(__a._M_a, std::forward<_Args>(__args)...); |
652 | __guard = nullptr; |
653 | _M_pi = __pi; |
654 | __p = __pi->_M_ptr(); |
655 | } |
656 | |
657 | #if _GLIBCXX_USE_DEPRECATED |
658 | #pragma GCC diagnostic push |
659 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
660 | // Special case for auto_ptr<_Tp> to provide the strong guarantee. |
661 | template<typename _Tp> |
662 | explicit |
663 | __shared_count(std::auto_ptr<_Tp>&& __r); |
664 | #pragma GCC diagnostic pop |
665 | #endif |
666 | |
667 | // Special case for unique_ptr<_Tp,_Del> to provide the strong guarantee. |
668 | template<typename _Tp, typename _Del> |
669 | explicit |
670 | __shared_count(std::unique_ptr<_Tp, _Del>&& __r) : _M_pi(0) |
671 | { |
672 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
673 | // 2415. Inconsistency between unique_ptr and shared_ptr |
674 | if (__r.get() == nullptr) |
675 | return; |
676 | |
677 | using _Ptr = typename unique_ptr<_Tp, _Del>::pointer; |
678 | using _Del2 = typename conditional<is_reference<_Del>::value, |
679 | reference_wrapper<typename remove_reference<_Del>::type>, |
680 | _Del>::type; |
681 | using _Sp_cd_type |
682 | = _Sp_counted_deleter<_Ptr, _Del2, allocator<void>, _Lp>; |
683 | using _Alloc = allocator<_Sp_cd_type>; |
684 | using _Alloc_traits = allocator_traits<_Alloc>; |
685 | _Alloc __a; |
686 | _Sp_cd_type* __mem = _Alloc_traits::allocate(__a, 1); |
687 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
688 | // 3548. shared_ptr construction from unique_ptr should move |
689 | // (not copy) the deleter |
690 | _Alloc_traits::construct(__a, __mem, __r.release(), |
691 | std::forward<_Del>(__r.get_deleter())); |
692 | _M_pi = __mem; |
693 | } |
694 | |
695 | // Throw bad_weak_ptr when __r._M_get_use_count() == 0. |
696 | explicit __shared_count(const __weak_count<_Lp>& __r); |
697 | |
698 | // Does not throw if __r._M_get_use_count() == 0, caller must check. |
699 | explicit |
700 | __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t) noexcept; |
701 | |
702 | ~__shared_count() noexcept |
703 | { |
704 | if (_M_pi != nullptr) |
705 | _M_pi->_M_release(); |
706 | } |
707 | |
708 | __shared_count(const __shared_count& __r) noexcept |
709 | : _M_pi(__r._M_pi) |
710 | { |
711 | if (_M_pi != nullptr) |
712 | _M_pi->_M_add_ref_copy(); |
713 | } |
714 | |
715 | __shared_count& |
716 | operator=(const __shared_count& __r) noexcept |
717 | { |
718 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
719 | if (__tmp != _M_pi) |
720 | { |
721 | if (__tmp != nullptr) |
722 | __tmp->_M_add_ref_copy(); |
723 | if (_M_pi != nullptr) |
724 | _M_pi->_M_release(); |
725 | _M_pi = __tmp; |
726 | } |
727 | return *this; |
728 | } |
729 | |
730 | void |
731 | _M_swap(__shared_count& __r) noexcept |
732 | { |
733 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
734 | __r._M_pi = _M_pi; |
735 | _M_pi = __tmp; |
736 | } |
737 | |
738 | long |
739 | _M_get_use_count() const noexcept |
740 | { return _M_pi ? _M_pi->_M_get_use_count() : 0; } |
741 | |
742 | bool |
743 | _M_unique() const noexcept |
744 | { return this->_M_get_use_count() == 1; } |
745 | |
746 | void* |
747 | _M_get_deleter(const std::type_info& __ti) const noexcept |
748 | { return _M_pi ? _M_pi->_M_get_deleter(__ti) : nullptr; } |
749 | |
750 | bool |
751 | _M_less(const __shared_count& __rhs) const noexcept |
752 | { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } |
753 | |
754 | bool |
755 | _M_less(const __weak_count<_Lp>& __rhs) const noexcept |
756 | { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } |
757 | |
758 | // Friend function injected into enclosing namespace and found by ADL |
759 | friend inline bool |
760 | operator==(const __shared_count& __a, const __shared_count& __b) noexcept |
761 | { return __a._M_pi == __b._M_pi; } |
762 | |
763 | private: |
764 | friend class __weak_count<_Lp>; |
765 | |
766 | _Sp_counted_base<_Lp>* _M_pi; |
767 | }; |
768 | |
769 | |
770 | template<_Lock_policy _Lp> |
771 | class __weak_count |
772 | { |
773 | public: |
774 | constexpr __weak_count() noexcept : _M_pi(nullptr) |
775 | { } |
776 | |
777 | __weak_count(const __shared_count<_Lp>& __r) noexcept |
778 | : _M_pi(__r._M_pi) |
779 | { |
780 | if (_M_pi != nullptr) |
781 | _M_pi->_M_weak_add_ref(); |
782 | } |
783 | |
784 | __weak_count(const __weak_count& __r) noexcept |
785 | : _M_pi(__r._M_pi) |
786 | { |
787 | if (_M_pi != nullptr) |
788 | _M_pi->_M_weak_add_ref(); |
789 | } |
790 | |
791 | __weak_count(__weak_count&& __r) noexcept |
792 | : _M_pi(__r._M_pi) |
793 | { __r._M_pi = nullptr; } |
794 | |
795 | ~__weak_count() noexcept |
796 | { |
797 | if (_M_pi != nullptr) |
798 | _M_pi->_M_weak_release(); |
799 | } |
800 | |
801 | __weak_count& |
802 | operator=(const __shared_count<_Lp>& __r) noexcept |
803 | { |
804 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
805 | if (__tmp != nullptr) |
806 | __tmp->_M_weak_add_ref(); |
807 | if (_M_pi != nullptr) |
808 | _M_pi->_M_weak_release(); |
809 | _M_pi = __tmp; |
810 | return *this; |
811 | } |
812 | |
813 | __weak_count& |
814 | operator=(const __weak_count& __r) noexcept |
815 | { |
816 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
817 | if (__tmp != nullptr) |
818 | __tmp->_M_weak_add_ref(); |
819 | if (_M_pi != nullptr) |
820 | _M_pi->_M_weak_release(); |
821 | _M_pi = __tmp; |
822 | return *this; |
823 | } |
824 | |
825 | __weak_count& |
826 | operator=(__weak_count&& __r) noexcept |
827 | { |
828 | if (_M_pi != nullptr) |
829 | _M_pi->_M_weak_release(); |
830 | _M_pi = __r._M_pi; |
831 | __r._M_pi = nullptr; |
832 | return *this; |
833 | } |
834 | |
835 | void |
836 | _M_swap(__weak_count& __r) noexcept |
837 | { |
838 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
839 | __r._M_pi = _M_pi; |
840 | _M_pi = __tmp; |
841 | } |
842 | |
843 | long |
844 | _M_get_use_count() const noexcept |
845 | { return _M_pi != nullptr ? _M_pi->_M_get_use_count() : 0; } |
846 | |
847 | bool |
848 | _M_less(const __weak_count& __rhs) const noexcept |
849 | { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } |
850 | |
851 | bool |
852 | _M_less(const __shared_count<_Lp>& __rhs) const noexcept |
853 | { return std::less<_Sp_counted_base<_Lp>*>()(this->_M_pi, __rhs._M_pi); } |
854 | |
855 | // Friend function injected into enclosing namespace and found by ADL |
856 | friend inline bool |
857 | operator==(const __weak_count& __a, const __weak_count& __b) noexcept |
858 | { return __a._M_pi == __b._M_pi; } |
859 | |
860 | private: |
861 | friend class __shared_count<_Lp>; |
862 | |
863 | _Sp_counted_base<_Lp>* _M_pi; |
864 | }; |
865 | |
866 | // Now that __weak_count is defined we can define this constructor: |
867 | template<_Lock_policy _Lp> |
868 | inline |
869 | __shared_count<_Lp>::__shared_count(const __weak_count<_Lp>& __r) |
870 | : _M_pi(__r._M_pi) |
871 | { |
872 | if (_M_pi == nullptr || !_M_pi->_M_add_ref_lock_nothrow()) |
873 | __throw_bad_weak_ptr(); |
874 | } |
875 | |
876 | // Now that __weak_count is defined we can define this constructor: |
877 | template<_Lock_policy _Lp> |
878 | inline |
879 | __shared_count<_Lp>:: |
880 | __shared_count(const __weak_count<_Lp>& __r, std::nothrow_t) noexcept |
881 | : _M_pi(__r._M_pi) |
882 | { |
883 | if (_M_pi && !_M_pi->_M_add_ref_lock_nothrow()) |
884 | _M_pi = nullptr; |
885 | } |
886 | |
887 | #define __cpp_lib_shared_ptr_arrays 201611L |
888 | |
889 | // Helper traits for shared_ptr of array: |
890 | |
891 | // A pointer type Y* is said to be compatible with a pointer type T* when |
892 | // either Y* is convertible to T* or Y is U[N] and T is U cv []. |
893 | template<typename _Yp_ptr, typename _Tp_ptr> |
894 | struct __sp_compatible_with |
895 | : false_type |
896 | { }; |
897 | |
898 | template<typename _Yp, typename _Tp> |
899 | struct __sp_compatible_with<_Yp*, _Tp*> |
900 | : is_convertible<_Yp*, _Tp*>::type |
901 | { }; |
902 | |
903 | template<typename _Up, size_t _Nm> |
904 | struct __sp_compatible_with<_Up(*)[_Nm], _Up(*)[]> |
905 | : true_type |
906 | { }; |
907 | |
908 | template<typename _Up, size_t _Nm> |
909 | struct __sp_compatible_with<_Up(*)[_Nm], const _Up(*)[]> |
910 | : true_type |
911 | { }; |
912 | |
913 | template<typename _Up, size_t _Nm> |
914 | struct __sp_compatible_with<_Up(*)[_Nm], volatile _Up(*)[]> |
915 | : true_type |
916 | { }; |
917 | |
918 | template<typename _Up, size_t _Nm> |
919 | struct __sp_compatible_with<_Up(*)[_Nm], const volatile _Up(*)[]> |
920 | : true_type |
921 | { }; |
922 | |
923 | // Test conversion from Y(*)[N] to U(*)[N] without forming invalid type Y[N]. |
924 | template<typename _Up, size_t _Nm, typename _Yp, typename = void> |
925 | struct __sp_is_constructible_arrN |
926 | : false_type |
927 | { }; |
928 | |
929 | template<typename _Up, size_t _Nm, typename _Yp> |
930 | struct __sp_is_constructible_arrN<_Up, _Nm, _Yp, __void_t<_Yp[_Nm]>> |
931 | : is_convertible<_Yp(*)[_Nm], _Up(*)[_Nm]>::type |
932 | { }; |
933 | |
934 | // Test conversion from Y(*)[] to U(*)[] without forming invalid type Y[]. |
935 | template<typename _Up, typename _Yp, typename = void> |
936 | struct __sp_is_constructible_arr |
937 | : false_type |
938 | { }; |
939 | |
940 | template<typename _Up, typename _Yp> |
941 | struct __sp_is_constructible_arr<_Up, _Yp, __void_t<_Yp[]>> |
942 | : is_convertible<_Yp(*)[], _Up(*)[]>::type |
943 | { }; |
944 | |
945 | // Trait to check if shared_ptr<T> can be constructed from Y*. |
946 | template<typename _Tp, typename _Yp> |
947 | struct __sp_is_constructible; |
948 | |
949 | // When T is U[N], Y(*)[N] shall be convertible to T*; |
950 | template<typename _Up, size_t _Nm, typename _Yp> |
951 | struct __sp_is_constructible<_Up[_Nm], _Yp> |
952 | : __sp_is_constructible_arrN<_Up, _Nm, _Yp>::type |
953 | { }; |
954 | |
955 | // when T is U[], Y(*)[] shall be convertible to T*; |
956 | template<typename _Up, typename _Yp> |
957 | struct __sp_is_constructible<_Up[], _Yp> |
958 | : __sp_is_constructible_arr<_Up, _Yp>::type |
959 | { }; |
960 | |
961 | // otherwise, Y* shall be convertible to T*. |
962 | template<typename _Tp, typename _Yp> |
963 | struct __sp_is_constructible |
964 | : is_convertible<_Yp*, _Tp*>::type |
965 | { }; |
966 | |
967 | |
968 | // Define operator* and operator-> for shared_ptr<T>. |
969 | template<typename _Tp, _Lock_policy _Lp, |
970 | bool = is_array<_Tp>::value, bool = is_void<_Tp>::value> |
971 | class __shared_ptr_access |
972 | { |
973 | public: |
974 | using element_type = _Tp; |
975 | |
976 | element_type& |
977 | operator*() const noexcept |
978 | { |
979 | __glibcxx_assert(_M_get() != nullptr); |
980 | return *_M_get(); |
981 | } |
982 | |
983 | element_type* |
984 | operator->() const noexcept |
985 | { |
986 | _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr); |
987 | return _M_get(); |
988 | } |
989 | |
990 | private: |
991 | element_type* |
992 | _M_get() const noexcept |
993 | { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); } |
994 | }; |
995 | |
996 | // Define operator-> for shared_ptr<cv void>. |
997 | template<typename _Tp, _Lock_policy _Lp> |
998 | class __shared_ptr_access<_Tp, _Lp, false, true> |
999 | { |
1000 | public: |
1001 | using element_type = _Tp; |
1002 | |
1003 | element_type* |
1004 | operator->() const noexcept |
1005 | { |
1006 | auto __ptr = static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); |
1007 | _GLIBCXX_DEBUG_PEDASSERT(__ptr != nullptr); |
1008 | return __ptr; |
1009 | } |
1010 | }; |
1011 | |
1012 | // Define operator[] for shared_ptr<T[]> and shared_ptr<T[N]>. |
1013 | template<typename _Tp, _Lock_policy _Lp> |
1014 | class __shared_ptr_access<_Tp, _Lp, true, false> |
1015 | { |
1016 | public: |
1017 | using element_type = typename remove_extent<_Tp>::type; |
1018 | |
1019 | #if __cplusplus <= 201402L |
1020 | [[__deprecated__("shared_ptr<T[]>::operator* is absent from C++17" )]] |
1021 | element_type& |
1022 | operator*() const noexcept |
1023 | { |
1024 | __glibcxx_assert(_M_get() != nullptr); |
1025 | return *_M_get(); |
1026 | } |
1027 | |
1028 | [[__deprecated__("shared_ptr<T[]>::operator-> is absent from C++17" )]] |
1029 | element_type* |
1030 | operator->() const noexcept |
1031 | { |
1032 | _GLIBCXX_DEBUG_PEDASSERT(_M_get() != nullptr); |
1033 | return _M_get(); |
1034 | } |
1035 | #endif |
1036 | |
1037 | element_type& |
1038 | operator[](ptrdiff_t __i) const |
1039 | { |
1040 | __glibcxx_assert(_M_get() != nullptr); |
1041 | __glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value); |
1042 | return _M_get()[__i]; |
1043 | } |
1044 | |
1045 | private: |
1046 | element_type* |
1047 | _M_get() const noexcept |
1048 | { return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); } |
1049 | }; |
1050 | |
1051 | template<typename _Tp, _Lock_policy _Lp> |
1052 | class __shared_ptr |
1053 | : public __shared_ptr_access<_Tp, _Lp> |
1054 | { |
1055 | public: |
1056 | using element_type = typename remove_extent<_Tp>::type; |
1057 | |
1058 | private: |
1059 | // Constraint for taking ownership of a pointer of type _Yp*: |
1060 | template<typename _Yp> |
1061 | using _SafeConv |
1062 | = typename enable_if<__sp_is_constructible<_Tp, _Yp>::value>::type; |
1063 | |
1064 | // Constraint for construction from shared_ptr and weak_ptr: |
1065 | template<typename _Yp, typename _Res = void> |
1066 | using _Compatible = typename |
1067 | enable_if<__sp_compatible_with<_Yp*, _Tp*>::value, _Res>::type; |
1068 | |
1069 | // Constraint for assignment from shared_ptr and weak_ptr: |
1070 | template<typename _Yp> |
1071 | using _Assignable = _Compatible<_Yp, __shared_ptr&>; |
1072 | |
1073 | // Constraint for construction from unique_ptr: |
1074 | template<typename _Yp, typename _Del, typename _Res = void, |
1075 | typename _Ptr = typename unique_ptr<_Yp, _Del>::pointer> |
1076 | using _UniqCompatible = __enable_if_t<__and_< |
1077 | __sp_compatible_with<_Yp*, _Tp*>, |
1078 | is_convertible<_Ptr, element_type*>, |
1079 | is_move_constructible<_Del> |
1080 | >::value, _Res>; |
1081 | |
1082 | // Constraint for assignment from unique_ptr: |
1083 | template<typename _Yp, typename _Del> |
1084 | using _UniqAssignable = _UniqCompatible<_Yp, _Del, __shared_ptr&>; |
1085 | |
1086 | public: |
1087 | |
1088 | #if __cplusplus > 201402L |
1089 | using weak_type = __weak_ptr<_Tp, _Lp>; |
1090 | #endif |
1091 | |
1092 | constexpr __shared_ptr() noexcept |
1093 | : _M_ptr(0), _M_refcount() |
1094 | { } |
1095 | |
1096 | template<typename _Yp, typename = _SafeConv<_Yp>> |
1097 | explicit |
1098 | __shared_ptr(_Yp* __p) |
1099 | : _M_ptr(__p), _M_refcount(__p, typename is_array<_Tp>::type()) |
1100 | { |
1101 | static_assert( !is_void<_Yp>::value, "incomplete type" ); |
1102 | static_assert( sizeof(_Yp) > 0, "incomplete type" ); |
1103 | _M_enable_shared_from_this_with(__p); |
1104 | } |
1105 | |
1106 | template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>> |
1107 | __shared_ptr(_Yp* __p, _Deleter __d) |
1108 | : _M_ptr(__p), _M_refcount(__p, std::move(__d)) |
1109 | { |
1110 | static_assert(__is_invocable<_Deleter&, _Yp*&>::value, |
1111 | "deleter expression d(p) is well-formed" ); |
1112 | _M_enable_shared_from_this_with(__p); |
1113 | } |
1114 | |
1115 | template<typename _Yp, typename _Deleter, typename _Alloc, |
1116 | typename = _SafeConv<_Yp>> |
1117 | __shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a) |
1118 | : _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a)) |
1119 | { |
1120 | static_assert(__is_invocable<_Deleter&, _Yp*&>::value, |
1121 | "deleter expression d(p) is well-formed" ); |
1122 | _M_enable_shared_from_this_with(__p); |
1123 | } |
1124 | |
1125 | template<typename _Deleter> |
1126 | __shared_ptr(nullptr_t __p, _Deleter __d) |
1127 | : _M_ptr(0), _M_refcount(__p, std::move(__d)) |
1128 | { } |
1129 | |
1130 | template<typename _Deleter, typename _Alloc> |
1131 | __shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a) |
1132 | : _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a)) |
1133 | { } |
1134 | |
1135 | // Aliasing constructor |
1136 | template<typename _Yp> |
1137 | __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r, |
1138 | element_type* __p) noexcept |
1139 | : _M_ptr(__p), _M_refcount(__r._M_refcount) // never throws |
1140 | { } |
1141 | |
1142 | // Aliasing constructor |
1143 | template<typename _Yp> |
1144 | __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r, |
1145 | element_type* __p) noexcept |
1146 | : _M_ptr(__p), _M_refcount() |
1147 | { |
1148 | _M_refcount._M_swap(__r._M_refcount); |
1149 | __r._M_ptr = nullptr; |
1150 | } |
1151 | |
1152 | __shared_ptr(const __shared_ptr&) noexcept = default; |
1153 | __shared_ptr& operator=(const __shared_ptr&) noexcept = default; |
1154 | ~__shared_ptr() = default; |
1155 | |
1156 | template<typename _Yp, typename = _Compatible<_Yp>> |
1157 | __shared_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept |
1158 | : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) |
1159 | { } |
1160 | |
1161 | __shared_ptr(__shared_ptr&& __r) noexcept |
1162 | : _M_ptr(__r._M_ptr), _M_refcount() |
1163 | { |
1164 | _M_refcount._M_swap(__r._M_refcount); |
1165 | __r._M_ptr = nullptr; |
1166 | } |
1167 | |
1168 | template<typename _Yp, typename = _Compatible<_Yp>> |
1169 | __shared_ptr(__shared_ptr<_Yp, _Lp>&& __r) noexcept |
1170 | : _M_ptr(__r._M_ptr), _M_refcount() |
1171 | { |
1172 | _M_refcount._M_swap(__r._M_refcount); |
1173 | __r._M_ptr = nullptr; |
1174 | } |
1175 | |
1176 | template<typename _Yp, typename = _Compatible<_Yp>> |
1177 | explicit __shared_ptr(const __weak_ptr<_Yp, _Lp>& __r) |
1178 | : _M_refcount(__r._M_refcount) // may throw |
1179 | { |
1180 | // It is now safe to copy __r._M_ptr, as |
1181 | // _M_refcount(__r._M_refcount) did not throw. |
1182 | _M_ptr = __r._M_ptr; |
1183 | } |
1184 | |
1185 | // If an exception is thrown this constructor has no effect. |
1186 | template<typename _Yp, typename _Del, |
1187 | typename = _UniqCompatible<_Yp, _Del>> |
1188 | __shared_ptr(unique_ptr<_Yp, _Del>&& __r) |
1189 | : _M_ptr(__r.get()), _M_refcount() |
1190 | { |
1191 | auto __raw = __to_address(__r.get()); |
1192 | _M_refcount = __shared_count<_Lp>(std::move(__r)); |
1193 | _M_enable_shared_from_this_with(__raw); |
1194 | } |
1195 | |
1196 | #if __cplusplus <= 201402L && _GLIBCXX_USE_DEPRECATED |
1197 | protected: |
1198 | // If an exception is thrown this constructor has no effect. |
1199 | template<typename _Tp1, typename _Del, |
1200 | typename enable_if<__and_< |
1201 | __not_<is_array<_Tp>>, is_array<_Tp1>, |
1202 | is_convertible<typename unique_ptr<_Tp1, _Del>::pointer, _Tp*> |
1203 | >::value, bool>::type = true> |
1204 | __shared_ptr(unique_ptr<_Tp1, _Del>&& __r, __sp_array_delete) |
1205 | : _M_ptr(__r.get()), _M_refcount() |
1206 | { |
1207 | auto __raw = __to_address(__r.get()); |
1208 | _M_refcount = __shared_count<_Lp>(std::move(__r)); |
1209 | _M_enable_shared_from_this_with(__raw); |
1210 | } |
1211 | public: |
1212 | #endif |
1213 | |
1214 | #if _GLIBCXX_USE_DEPRECATED |
1215 | #pragma GCC diagnostic push |
1216 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
1217 | // Postcondition: use_count() == 1 and __r.get() == 0 |
1218 | template<typename _Yp, typename = _Compatible<_Yp>> |
1219 | __shared_ptr(auto_ptr<_Yp>&& __r); |
1220 | #pragma GCC diagnostic pop |
1221 | #endif |
1222 | |
1223 | constexpr __shared_ptr(nullptr_t) noexcept : __shared_ptr() { } |
1224 | |
1225 | template<typename _Yp> |
1226 | _Assignable<_Yp> |
1227 | operator=(const __shared_ptr<_Yp, _Lp>& __r) noexcept |
1228 | { |
1229 | _M_ptr = __r._M_ptr; |
1230 | _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw |
1231 | return *this; |
1232 | } |
1233 | |
1234 | #if _GLIBCXX_USE_DEPRECATED |
1235 | #pragma GCC diagnostic push |
1236 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
1237 | template<typename _Yp> |
1238 | _Assignable<_Yp> |
1239 | operator=(auto_ptr<_Yp>&& __r) |
1240 | { |
1241 | __shared_ptr(std::move(__r)).swap(*this); |
1242 | return *this; |
1243 | } |
1244 | #pragma GCC diagnostic pop |
1245 | #endif |
1246 | |
1247 | __shared_ptr& |
1248 | operator=(__shared_ptr&& __r) noexcept |
1249 | { |
1250 | __shared_ptr(std::move(__r)).swap(*this); |
1251 | return *this; |
1252 | } |
1253 | |
1254 | template<class _Yp> |
1255 | _Assignable<_Yp> |
1256 | operator=(__shared_ptr<_Yp, _Lp>&& __r) noexcept |
1257 | { |
1258 | __shared_ptr(std::move(__r)).swap(*this); |
1259 | return *this; |
1260 | } |
1261 | |
1262 | template<typename _Yp, typename _Del> |
1263 | _UniqAssignable<_Yp, _Del> |
1264 | operator=(unique_ptr<_Yp, _Del>&& __r) |
1265 | { |
1266 | __shared_ptr(std::move(__r)).swap(*this); |
1267 | return *this; |
1268 | } |
1269 | |
1270 | void |
1271 | reset() noexcept |
1272 | { __shared_ptr().swap(*this); } |
1273 | |
1274 | template<typename _Yp> |
1275 | _SafeConv<_Yp> |
1276 | reset(_Yp* __p) // _Yp must be complete. |
1277 | { |
1278 | // Catch self-reset errors. |
1279 | __glibcxx_assert(__p == nullptr || __p != _M_ptr); |
1280 | __shared_ptr(__p).swap(*this); |
1281 | } |
1282 | |
1283 | template<typename _Yp, typename _Deleter> |
1284 | _SafeConv<_Yp> |
1285 | reset(_Yp* __p, _Deleter __d) |
1286 | { __shared_ptr(__p, std::move(__d)).swap(*this); } |
1287 | |
1288 | template<typename _Yp, typename _Deleter, typename _Alloc> |
1289 | _SafeConv<_Yp> |
1290 | reset(_Yp* __p, _Deleter __d, _Alloc __a) |
1291 | { __shared_ptr(__p, std::move(__d), std::move(__a)).swap(*this); } |
1292 | |
1293 | /// Return the stored pointer. |
1294 | element_type* |
1295 | get() const noexcept |
1296 | { return _M_ptr; } |
1297 | |
1298 | /// Return true if the stored pointer is not null. |
1299 | explicit operator bool() const noexcept |
1300 | { return _M_ptr != nullptr; } |
1301 | |
1302 | /// Return true if use_count() == 1. |
1303 | bool |
1304 | unique() const noexcept |
1305 | { return _M_refcount._M_unique(); } |
1306 | |
1307 | /// If *this owns a pointer, return the number of owners, otherwise zero. |
1308 | long |
1309 | use_count() const noexcept |
1310 | { return _M_refcount._M_get_use_count(); } |
1311 | |
1312 | /// Exchange both the owned pointer and the stored pointer. |
1313 | void |
1314 | swap(__shared_ptr<_Tp, _Lp>& __other) noexcept |
1315 | { |
1316 | std::swap(_M_ptr, __other._M_ptr); |
1317 | _M_refcount._M_swap(__other._M_refcount); |
1318 | } |
1319 | |
1320 | /** @brief Define an ordering based on ownership. |
1321 | * |
1322 | * This function defines a strict weak ordering between two shared_ptr |
1323 | * or weak_ptr objects, such that one object is less than the other |
1324 | * unless they share ownership of the same pointer, or are both empty. |
1325 | * @{ |
1326 | */ |
1327 | template<typename _Tp1> |
1328 | bool |
1329 | owner_before(__shared_ptr<_Tp1, _Lp> const& __rhs) const noexcept |
1330 | { return _M_refcount._M_less(__rhs._M_refcount); } |
1331 | |
1332 | template<typename _Tp1> |
1333 | bool |
1334 | owner_before(__weak_ptr<_Tp1, _Lp> const& __rhs) const noexcept |
1335 | { return _M_refcount._M_less(__rhs._M_refcount); } |
1336 | /// @} |
1337 | |
1338 | protected: |
1339 | // This constructor is non-standard, it is used by allocate_shared. |
1340 | template<typename _Alloc, typename... _Args> |
1341 | __shared_ptr(_Sp_alloc_shared_tag<_Alloc> __tag, _Args&&... __args) |
1342 | : _M_ptr(), _M_refcount(_M_ptr, __tag, std::forward<_Args>(__args)...) |
1343 | { _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 | __shared_ptr(const __weak_ptr<_Tp, _Lp>& __r, std::nothrow_t) noexcept |
1353 | : _M_refcount(__r._M_refcount, std::nothrow) |
1354 | { |
1355 | _M_ptr = _M_refcount._M_get_use_count() ? __r._M_ptr : nullptr; |
1356 | } |
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 | _M_enable_shared_from_this_with(_Yp*) noexcept |
1387 | { } |
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 | #ifdef __cpp_lib_three_way_comparison |
1420 | template<typename _Tp, typename _Up, _Lock_policy _Lp> |
1421 | inline strong_ordering |
1422 | operator<=>(const __shared_ptr<_Tp, _Lp>& __a, |
1423 | const __shared_ptr<_Up, _Lp>& __b) noexcept |
1424 | { return compare_three_way()(__a.get(), __b.get()); } |
1425 | |
1426 | template<typename _Tp, _Lock_policy _Lp> |
1427 | inline strong_ordering |
1428 | operator<=>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept |
1429 | { |
1430 | using pointer = typename __shared_ptr<_Tp, _Lp>::element_type*; |
1431 | return compare_three_way()(__a.get(), static_cast<pointer>(nullptr)); |
1432 | } |
1433 | #else |
1434 | template<typename _Tp, _Lock_policy _Lp> |
1435 | inline bool |
1436 | operator==(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept |
1437 | { return !__a; } |
1438 | |
1439 | template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> |
1440 | inline bool |
1441 | operator!=(const __shared_ptr<_Tp1, _Lp>& __a, |
1442 | const __shared_ptr<_Tp2, _Lp>& __b) noexcept |
1443 | { return __a.get() != __b.get(); } |
1444 | |
1445 | template<typename _Tp, _Lock_policy _Lp> |
1446 | inline bool |
1447 | operator!=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept |
1448 | { return (bool)__a; } |
1449 | |
1450 | template<typename _Tp, _Lock_policy _Lp> |
1451 | inline bool |
1452 | operator!=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept |
1453 | { return (bool)__a; } |
1454 | |
1455 | template<typename _Tp, typename _Up, _Lock_policy _Lp> |
1456 | inline bool |
1457 | operator<(const __shared_ptr<_Tp, _Lp>& __a, |
1458 | const __shared_ptr<_Up, _Lp>& __b) noexcept |
1459 | { |
1460 | using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type; |
1461 | using _Up_elt = typename __shared_ptr<_Up, _Lp>::element_type; |
1462 | using _Vp = typename common_type<_Tp_elt*, _Up_elt*>::type; |
1463 | return less<_Vp>()(__a.get(), __b.get()); |
1464 | } |
1465 | |
1466 | template<typename _Tp, _Lock_policy _Lp> |
1467 | inline bool |
1468 | operator<(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept |
1469 | { |
1470 | using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type; |
1471 | return less<_Tp_elt*>()(__a.get(), nullptr); |
1472 | } |
1473 | |
1474 | template<typename _Tp, _Lock_policy _Lp> |
1475 | inline bool |
1476 | operator<(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept |
1477 | { |
1478 | using _Tp_elt = typename __shared_ptr<_Tp, _Lp>::element_type; |
1479 | return less<_Tp_elt*>()(nullptr, __a.get()); |
1480 | } |
1481 | |
1482 | template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> |
1483 | inline bool |
1484 | operator<=(const __shared_ptr<_Tp1, _Lp>& __a, |
1485 | const __shared_ptr<_Tp2, _Lp>& __b) noexcept |
1486 | { return !(__b < __a); } |
1487 | |
1488 | template<typename _Tp, _Lock_policy _Lp> |
1489 | inline bool |
1490 | operator<=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept |
1491 | { return !(nullptr < __a); } |
1492 | |
1493 | template<typename _Tp, _Lock_policy _Lp> |
1494 | inline bool |
1495 | operator<=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept |
1496 | { return !(__a < nullptr); } |
1497 | |
1498 | template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> |
1499 | inline bool |
1500 | operator>(const __shared_ptr<_Tp1, _Lp>& __a, |
1501 | const __shared_ptr<_Tp2, _Lp>& __b) noexcept |
1502 | { return (__b < __a); } |
1503 | |
1504 | template<typename _Tp, _Lock_policy _Lp> |
1505 | inline bool |
1506 | operator>(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept |
1507 | { return nullptr < __a; } |
1508 | |
1509 | template<typename _Tp, _Lock_policy _Lp> |
1510 | inline bool |
1511 | operator>(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept |
1512 | { return __a < nullptr; } |
1513 | |
1514 | template<typename _Tp1, typename _Tp2, _Lock_policy _Lp> |
1515 | inline bool |
1516 | operator>=(const __shared_ptr<_Tp1, _Lp>& __a, |
1517 | const __shared_ptr<_Tp2, _Lp>& __b) noexcept |
1518 | { return !(__a < __b); } |
1519 | |
1520 | template<typename _Tp, _Lock_policy _Lp> |
1521 | inline bool |
1522 | operator>=(const __shared_ptr<_Tp, _Lp>& __a, nullptr_t) noexcept |
1523 | { return !(__a < nullptr); } |
1524 | |
1525 | template<typename _Tp, _Lock_policy _Lp> |
1526 | inline bool |
1527 | operator>=(nullptr_t, const __shared_ptr<_Tp, _Lp>& __a) noexcept |
1528 | { return !(nullptr < __a); } |
1529 | #endif // three-way comparison |
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 | ~__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 | __weak_ptr(const __shared_ptr<_Yp, _Lp>& __r) noexcept |
1633 | : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) |
1634 | { } |
1635 | |
1636 | __weak_ptr(__weak_ptr&& __r) noexcept |
1637 | : _M_ptr(__r._M_ptr), _M_refcount(std::move(__r._M_refcount)) |
1638 | { __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 | operator=(__weak_ptr&& __r) noexcept |
1668 | { |
1669 | __weak_ptr(std::move(__r)).swap(*this); |
1670 | return *this; |
1671 | } |
1672 | |
1673 | template<typename _Yp> |
1674 | _Assignable<_Yp> |
1675 | operator=(__weak_ptr<_Yp, _Lp>&& __r) noexcept |
1676 | { |
1677 | _M_ptr = __r.lock().get(); |
1678 | _M_refcount = std::move(__r._M_refcount); |
1679 | __r._M_ptr = nullptr; |
1680 | return *this; |
1681 | } |
1682 | |
1683 | __shared_ptr<_Tp, _Lp> |
1684 | lock() const noexcept |
1685 | { return __shared_ptr<element_type, _Lp>(*this, std::nothrow); } |
1686 | |
1687 | long |
1688 | use_count() const noexcept |
1689 | { return _M_refcount._M_get_use_count(); } |
1690 | |
1691 | bool |
1692 | expired() const noexcept |
1693 | { return _M_refcount._M_get_use_count() == 0; } |
1694 | |
1695 | template<typename _Tp1> |
1696 | bool |
1697 | owner_before(const __shared_ptr<_Tp1, _Lp>& __rhs) const noexcept |
1698 | { return _M_refcount._M_less(__rhs._M_refcount); } |
1699 | |
1700 | template<typename _Tp1> |
1701 | bool |
1702 | owner_before(const __weak_ptr<_Tp1, _Lp>& __rhs) const noexcept |
1703 | { return _M_refcount._M_less(__rhs._M_refcount); } |
1704 | |
1705 | void |
1706 | reset() noexcept |
1707 | { __weak_ptr().swap(*this); } |
1708 | |
1709 | void |
1710 | swap(__weak_ptr& __s) noexcept |
1711 | { |
1712 | std::swap(_M_ptr, __s._M_ptr); |
1713 | _M_refcount._M_swap(__s._M_refcount); |
1714 | } |
1715 | |
1716 | private: |
1717 | // Used by __enable_shared_from_this. |
1718 | void |
1719 | _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) noexcept |
1720 | { |
1721 | if (use_count() == 0) |
1722 | { |
1723 | _M_ptr = __ptr; |
1724 | _M_refcount = __refcount; |
1725 | } |
1726 | } |
1727 | |
1728 | template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; |
1729 | template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; |
1730 | friend class __enable_shared_from_this<_Tp, _Lp>; |
1731 | friend class enable_shared_from_this<_Tp>; |
1732 | |
1733 | element_type* _M_ptr; // Contained pointer. |
1734 | __weak_count<_Lp> _M_refcount; // Reference counter. |
1735 | }; |
1736 | |
1737 | // 20.7.2.3.6 weak_ptr specialized algorithms. |
1738 | template<typename _Tp, _Lock_policy _Lp> |
1739 | inline void |
1740 | swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) noexcept |
1741 | { __a.swap(__b); } |
1742 | |
1743 | template<typename _Tp, typename _Tp1> |
1744 | struct _Sp_owner_less : public binary_function<_Tp, _Tp, bool> |
1745 | { |
1746 | bool |
1747 | operator()(const _Tp& __lhs, const _Tp& __rhs) const noexcept |
1748 | { return __lhs.owner_before(__rhs); } |
1749 | |
1750 | bool |
1751 | operator()(const _Tp& __lhs, const _Tp1& __rhs) const noexcept |
1752 | { return __lhs.owner_before(__rhs); } |
1753 | |
1754 | bool |
1755 | operator()(const _Tp1& __lhs, const _Tp& __rhs) const noexcept |
1756 | { return __lhs.owner_before(__rhs); } |
1757 | }; |
1758 | |
1759 | template<> |
1760 | struct _Sp_owner_less<void, void> |
1761 | { |
1762 | template<typename _Tp, typename _Up> |
1763 | auto |
1764 | operator()(const _Tp& __lhs, const _Up& __rhs) const noexcept |
1765 | -> decltype(__lhs.owner_before(__rhs)) |
1766 | { return __lhs.owner_before(__rhs); } |
1767 | |
1768 | using is_transparent = void; |
1769 | }; |
1770 | |
1771 | template<typename _Tp, _Lock_policy _Lp> |
1772 | struct owner_less<__shared_ptr<_Tp, _Lp>> |
1773 | : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>> |
1774 | { }; |
1775 | |
1776 | template<typename _Tp, _Lock_policy _Lp> |
1777 | struct owner_less<__weak_ptr<_Tp, _Lp>> |
1778 | : public _Sp_owner_less<__weak_ptr<_Tp, _Lp>, __shared_ptr<_Tp, _Lp>> |
1779 | { }; |
1780 | |
1781 | |
1782 | template<typename _Tp, _Lock_policy _Lp> |
1783 | class __enable_shared_from_this |
1784 | { |
1785 | protected: |
1786 | constexpr __enable_shared_from_this() noexcept { } |
1787 | |
1788 | __enable_shared_from_this(const __enable_shared_from_this&) noexcept { } |
1789 | |
1790 | __enable_shared_from_this& |
1791 | operator=(const __enable_shared_from_this&) noexcept |
1792 | { return *this; } |
1793 | |
1794 | ~__enable_shared_from_this() { } |
1795 | |
1796 | public: |
1797 | __shared_ptr<_Tp, _Lp> |
1798 | shared_from_this() |
1799 | { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); } |
1800 | |
1801 | __shared_ptr<const _Tp, _Lp> |
1802 | shared_from_this() const |
1803 | { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); } |
1804 | |
1805 | #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 |
1806 | __weak_ptr<_Tp, _Lp> |
1807 | weak_from_this() noexcept |
1808 | { return this->_M_weak_this; } |
1809 | |
1810 | __weak_ptr<const _Tp, _Lp> |
1811 | weak_from_this() const noexcept |
1812 | { return this->_M_weak_this; } |
1813 | #endif |
1814 | |
1815 | private: |
1816 | template<typename _Tp1> |
1817 | void |
1818 | _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const noexcept |
1819 | { _M_weak_this._M_assign(__p, __n); } |
1820 | |
1821 | friend const __enable_shared_from_this* |
1822 | __enable_shared_from_this_base(const __shared_count<_Lp>&, |
1823 | const __enable_shared_from_this* __p) |
1824 | { return __p; } |
1825 | |
1826 | template<typename, _Lock_policy> |
1827 | friend class __shared_ptr; |
1828 | |
1829 | mutable __weak_ptr<_Tp, _Lp> _M_weak_this; |
1830 | }; |
1831 | |
1832 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy, |
1833 | typename _Alloc, typename... _Args> |
1834 | inline __shared_ptr<_Tp, _Lp> |
1835 | __allocate_shared(const _Alloc& __a, _Args&&... __args) |
1836 | { |
1837 | static_assert(!is_array<_Tp>::value, "make_shared<T[]> not supported" ); |
1838 | |
1839 | return __shared_ptr<_Tp, _Lp>(_Sp_alloc_shared_tag<_Alloc>{__a}, |
1840 | std::forward<_Args>(__args)...); |
1841 | } |
1842 | |
1843 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy, |
1844 | typename... _Args> |
1845 | inline __shared_ptr<_Tp, _Lp> |
1846 | __make_shared(_Args&&... __args) |
1847 | { |
1848 | typedef typename std::remove_const<_Tp>::type _Tp_nc; |
1849 | return std::__allocate_shared<_Tp, _Lp>(std::allocator<_Tp_nc>(), |
1850 | std::forward<_Args>(__args)...); |
1851 | } |
1852 | |
1853 | /// std::hash specialization for __shared_ptr. |
1854 | template<typename _Tp, _Lock_policy _Lp> |
1855 | struct hash<__shared_ptr<_Tp, _Lp>> |
1856 | : public __hash_base<size_t, __shared_ptr<_Tp, _Lp>> |
1857 | { |
1858 | size_t |
1859 | operator()(const __shared_ptr<_Tp, _Lp>& __s) const noexcept |
1860 | { |
1861 | return hash<typename __shared_ptr<_Tp, _Lp>::element_type*>()( |
1862 | __s.get()); |
1863 | } |
1864 | }; |
1865 | |
1866 | _GLIBCXX_END_NAMESPACE_VERSION |
1867 | } // namespace |
1868 | |
1869 | #endif // _SHARED_PTR_BASE_H |
1870 | |