1 | // <tr1/shared_ptr.h> -*- 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 | // shared_count.hpp |
26 | // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. |
27 | |
28 | // shared_ptr.hpp |
29 | // Copyright (C) 1998, 1999 Greg Colvin and Beman Dawes. |
30 | // Copyright (C) 2001, 2002, 2003 Peter Dimov |
31 | |
32 | // weak_ptr.hpp |
33 | // Copyright (C) 2001, 2002, 2003 Peter Dimov |
34 | |
35 | // enable_shared_from_this.hpp |
36 | // Copyright (C) 2002 Peter Dimov |
37 | |
38 | // Distributed under the Boost Software License, Version 1.0. (See |
39 | // accompanying file LICENSE_1_0.txt or copy at |
40 | // http://www.boost.org/LICENSE_1_0.txt) |
41 | |
42 | // GCC Note: based on version 1.32.0 of the Boost library. |
43 | |
44 | /** @file tr1/shared_ptr.h |
45 | * This is an internal header file, included by other library headers. |
46 | * Do not attempt to use it directly. @headername{tr1/memory} |
47 | */ |
48 | |
49 | #ifndef _TR1_SHARED_PTR_H |
50 | #define _TR1_SHARED_PTR_H 1 |
51 | |
52 | namespace std _GLIBCXX_VISIBILITY(default) |
53 | { |
54 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
55 | |
56 | namespace tr1 |
57 | { |
58 | /** |
59 | * @brief Exception possibly thrown by @c shared_ptr. |
60 | * @ingroup exceptions |
61 | */ |
62 | class bad_weak_ptr : public std::exception |
63 | { |
64 | public: |
65 | virtual char const* |
66 | what() const throw() |
67 | { return "tr1::bad_weak_ptr" ; } |
68 | }; |
69 | |
70 | // Substitute for bad_weak_ptr object in the case of -fno-exceptions. |
71 | inline void |
72 | __throw_bad_weak_ptr() |
73 | { _GLIBCXX_THROW_OR_ABORT(bad_weak_ptr()); } |
74 | |
75 | using __gnu_cxx::_Lock_policy; |
76 | using __gnu_cxx::__default_lock_policy; |
77 | using __gnu_cxx::_S_single; |
78 | using __gnu_cxx::_S_mutex; |
79 | using __gnu_cxx::_S_atomic; |
80 | |
81 | // Empty helper class except when the template argument is _S_mutex. |
82 | template<_Lock_policy _Lp> |
83 | class _Mutex_base |
84 | { |
85 | protected: |
86 | // The atomic policy uses fully-fenced builtins, single doesn't care. |
87 | enum { _S_need_barriers = 0 }; |
88 | }; |
89 | |
90 | template<> |
91 | class _Mutex_base<_S_mutex> |
92 | : public __gnu_cxx::__mutex |
93 | { |
94 | protected: |
95 | // This policy is used when atomic builtins are not available. |
96 | // The replacement atomic operations might not have the necessary |
97 | // memory barriers. |
98 | enum { _S_need_barriers = 1 }; |
99 | }; |
100 | |
101 | template<_Lock_policy _Lp = __default_lock_policy> |
102 | class _Sp_counted_base |
103 | : public _Mutex_base<_Lp> |
104 | { |
105 | public: |
106 | _Sp_counted_base() |
107 | : _M_use_count(1), _M_weak_count(1) { } |
108 | |
109 | virtual |
110 | ~_Sp_counted_base() // nothrow |
111 | { } |
112 | |
113 | // Called when _M_use_count drops to zero, to release the resources |
114 | // managed by *this. |
115 | virtual void |
116 | _M_dispose() = 0; // nothrow |
117 | |
118 | // Called when _M_weak_count drops to zero. |
119 | virtual void |
120 | _M_destroy() // nothrow |
121 | { delete this; } |
122 | |
123 | virtual void* |
124 | _M_get_deleter(const std::type_info&) = 0; |
125 | |
126 | void |
127 | _M_add_ref_copy() |
128 | { __gnu_cxx::__atomic_add_dispatch(mem: &_M_use_count, val: 1); } |
129 | |
130 | void |
131 | _M_add_ref_lock(); |
132 | |
133 | void |
134 | _M_release() // nothrow |
135 | { |
136 | // Be race-detector-friendly. For more info see bits/c++config. |
137 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_use_count); |
138 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_use_count, val: -1) == 1) |
139 | { |
140 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_use_count); |
141 | _M_dispose(); |
142 | // There must be a memory barrier between dispose() and destroy() |
143 | // to ensure that the effects of dispose() are observed in the |
144 | // thread that runs destroy(). |
145 | // See http://gcc.gnu.org/ml/libstdc++/2005-11/msg00136.html |
146 | if (_Mutex_base<_Lp>::_S_need_barriers) |
147 | { |
148 | __atomic_thread_fence (__ATOMIC_ACQ_REL); |
149 | } |
150 | |
151 | // Be race-detector-friendly. For more info see bits/c++config. |
152 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); |
153 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_weak_count, |
154 | val: -1) == 1) |
155 | { |
156 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); |
157 | _M_destroy(); |
158 | } |
159 | } |
160 | } |
161 | |
162 | void |
163 | _M_weak_add_ref() // nothrow |
164 | { __gnu_cxx::__atomic_add_dispatch(mem: &_M_weak_count, val: 1); } |
165 | |
166 | void |
167 | _M_weak_release() // nothrow |
168 | { |
169 | // Be race-detector-friendly. For more info see bits/c++config. |
170 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_M_weak_count); |
171 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_weak_count, val: -1) == 1) |
172 | { |
173 | _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_M_weak_count); |
174 | if (_Mutex_base<_Lp>::_S_need_barriers) |
175 | { |
176 | // See _M_release(), |
177 | // destroy() must observe results of dispose() |
178 | __atomic_thread_fence (__ATOMIC_ACQ_REL); |
179 | } |
180 | _M_destroy(); |
181 | } |
182 | } |
183 | |
184 | long |
185 | _M_get_use_count() const // nothrow |
186 | { |
187 | // No memory barrier is used here so there is no synchronization |
188 | // with other threads. |
189 | return const_cast<const volatile _Atomic_word&>(_M_use_count); |
190 | } |
191 | |
192 | private: |
193 | _Sp_counted_base(_Sp_counted_base const&); |
194 | _Sp_counted_base& operator=(_Sp_counted_base const&); |
195 | |
196 | _Atomic_word _M_use_count; // #shared |
197 | _Atomic_word _M_weak_count; // #weak + (#shared != 0) |
198 | }; |
199 | |
200 | template<> |
201 | inline void |
202 | _Sp_counted_base<_S_single>:: |
203 | _M_add_ref_lock() |
204 | { |
205 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_use_count, val: 1) == 0) |
206 | { |
207 | _M_use_count = 0; |
208 | __throw_bad_weak_ptr(); |
209 | } |
210 | } |
211 | |
212 | template<> |
213 | inline void |
214 | _Sp_counted_base<_S_mutex>:: |
215 | _M_add_ref_lock() |
216 | { |
217 | __gnu_cxx::__scoped_lock sentry(*this); |
218 | if (__gnu_cxx::__exchange_and_add_dispatch(mem: &_M_use_count, val: 1) == 0) |
219 | { |
220 | _M_use_count = 0; |
221 | __throw_bad_weak_ptr(); |
222 | } |
223 | } |
224 | |
225 | template<> |
226 | inline void |
227 | _Sp_counted_base<_S_atomic>:: |
228 | _M_add_ref_lock() |
229 | { |
230 | // Perform lock-free add-if-not-zero operation. |
231 | _Atomic_word __count = _M_use_count; |
232 | do |
233 | { |
234 | if (__count == 0) |
235 | __throw_bad_weak_ptr(); |
236 | // Replace the current counter value with the old value + 1, as |
237 | // long as it's not changed meanwhile. |
238 | } |
239 | while (!__atomic_compare_exchange_n(&_M_use_count, &__count, __count + 1, |
240 | true, __ATOMIC_ACQ_REL, |
241 | __ATOMIC_RELAXED)); |
242 | } |
243 | |
244 | template<typename _Ptr, typename _Deleter, _Lock_policy _Lp> |
245 | class _Sp_counted_base_impl |
246 | : public _Sp_counted_base<_Lp> |
247 | { |
248 | public: |
249 | // Precondition: __d(__p) must not throw. |
250 | _Sp_counted_base_impl(_Ptr __p, _Deleter __d) |
251 | : _M_ptr(__p), _M_del(__d) { } |
252 | |
253 | virtual void |
254 | _M_dispose() // nothrow |
255 | { _M_del(_M_ptr); } |
256 | |
257 | virtual void* |
258 | _M_get_deleter(const std::type_info& __ti) |
259 | { |
260 | #if __cpp_rtti |
261 | return __ti == typeid(_Deleter) ? &_M_del : 0; |
262 | #else |
263 | return 0; |
264 | #endif |
265 | } |
266 | |
267 | private: |
268 | _Sp_counted_base_impl(const _Sp_counted_base_impl&); |
269 | _Sp_counted_base_impl& operator=(const _Sp_counted_base_impl&); |
270 | |
271 | _Ptr _M_ptr; // copy constructor must not throw |
272 | _Deleter _M_del; // copy constructor must not throw |
273 | }; |
274 | |
275 | template<_Lock_policy _Lp = __default_lock_policy> |
276 | class __weak_count; |
277 | |
278 | template<typename _Tp> |
279 | struct _Sp_deleter |
280 | { |
281 | typedef void result_type; |
282 | typedef _Tp* argument_type; |
283 | void operator()(_Tp* __p) const { delete __p; } |
284 | }; |
285 | |
286 | template<_Lock_policy _Lp = __default_lock_policy> |
287 | class __shared_count |
288 | { |
289 | public: |
290 | __shared_count() |
291 | : _M_pi(0) // nothrow |
292 | { } |
293 | |
294 | template<typename _Ptr> |
295 | __shared_count(_Ptr __p) : _M_pi(0) |
296 | { |
297 | __try |
298 | { |
299 | typedef typename std::tr1::remove_pointer<_Ptr>::type _Tp; |
300 | _M_pi = new _Sp_counted_base_impl<_Ptr, _Sp_deleter<_Tp>, _Lp>( |
301 | __p, _Sp_deleter<_Tp>()); |
302 | } |
303 | __catch(...) |
304 | { |
305 | delete __p; |
306 | __throw_exception_again; |
307 | } |
308 | } |
309 | |
310 | template<typename _Ptr, typename _Deleter> |
311 | __shared_count(_Ptr __p, _Deleter __d) : _M_pi(0) |
312 | { |
313 | __try |
314 | { |
315 | _M_pi = new _Sp_counted_base_impl<_Ptr, _Deleter, _Lp>(__p, __d); |
316 | } |
317 | __catch(...) |
318 | { |
319 | __d(__p); // Call _Deleter on __p. |
320 | __throw_exception_again; |
321 | } |
322 | } |
323 | |
324 | #if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED |
325 | #pragma GCC diagnostic push |
326 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
327 | // Special case for auto_ptr<_Tp> to provide the strong guarantee. |
328 | template<typename _Tp> |
329 | explicit |
330 | __shared_count(std::auto_ptr<_Tp>& __r) |
331 | : _M_pi(new _Sp_counted_base_impl<_Tp*, |
332 | _Sp_deleter<_Tp>, _Lp >(__r.get(), _Sp_deleter<_Tp>())) |
333 | { __r.release(); } |
334 | #pragma GCC diagnostic pop |
335 | #endif |
336 | |
337 | // Throw bad_weak_ptr when __r._M_get_use_count() == 0. |
338 | explicit |
339 | __shared_count(const __weak_count<_Lp>& __r); |
340 | |
341 | ~__shared_count() // nothrow |
342 | { |
343 | if (_M_pi != 0) |
344 | _M_pi->_M_release(); |
345 | } |
346 | |
347 | __shared_count(const __shared_count& __r) |
348 | : _M_pi(__r._M_pi) // nothrow |
349 | { |
350 | if (_M_pi != 0) |
351 | _M_pi->_M_add_ref_copy(); |
352 | } |
353 | |
354 | __shared_count& |
355 | operator=(const __shared_count& __r) // nothrow |
356 | { |
357 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
358 | if (__tmp != _M_pi) |
359 | { |
360 | if (__tmp != 0) |
361 | __tmp->_M_add_ref_copy(); |
362 | if (_M_pi != 0) |
363 | _M_pi->_M_release(); |
364 | _M_pi = __tmp; |
365 | } |
366 | return *this; |
367 | } |
368 | |
369 | void |
370 | _M_swap(__shared_count& __r) // nothrow |
371 | { |
372 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
373 | __r._M_pi = _M_pi; |
374 | _M_pi = __tmp; |
375 | } |
376 | |
377 | long |
378 | _M_get_use_count() const // nothrow |
379 | { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; } |
380 | |
381 | bool |
382 | _M_unique() const // nothrow |
383 | { return this->_M_get_use_count() == 1; } |
384 | |
385 | friend inline bool |
386 | operator==(const __shared_count& __a, const __shared_count& __b) |
387 | { return __a._M_pi == __b._M_pi; } |
388 | |
389 | friend inline bool |
390 | operator<(const __shared_count& __a, const __shared_count& __b) |
391 | { return std::less<_Sp_counted_base<_Lp>*>()(__a._M_pi, __b._M_pi); } |
392 | |
393 | void* |
394 | _M_get_deleter(const std::type_info& __ti) const |
395 | { return _M_pi ? _M_pi->_M_get_deleter(__ti) : 0; } |
396 | |
397 | private: |
398 | friend class __weak_count<_Lp>; |
399 | |
400 | _Sp_counted_base<_Lp>* _M_pi; |
401 | }; |
402 | |
403 | |
404 | template<_Lock_policy _Lp> |
405 | class __weak_count |
406 | { |
407 | public: |
408 | __weak_count() |
409 | : _M_pi(0) // nothrow |
410 | { } |
411 | |
412 | __weak_count(const __shared_count<_Lp>& __r) |
413 | : _M_pi(__r._M_pi) // nothrow |
414 | { |
415 | if (_M_pi != 0) |
416 | _M_pi->_M_weak_add_ref(); |
417 | } |
418 | |
419 | __weak_count(const __weak_count<_Lp>& __r) |
420 | : _M_pi(__r._M_pi) // nothrow |
421 | { |
422 | if (_M_pi != 0) |
423 | _M_pi->_M_weak_add_ref(); |
424 | } |
425 | |
426 | ~__weak_count() // nothrow |
427 | { |
428 | if (_M_pi != 0) |
429 | _M_pi->_M_weak_release(); |
430 | } |
431 | |
432 | __weak_count<_Lp>& |
433 | operator=(const __shared_count<_Lp>& __r) // nothrow |
434 | { |
435 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
436 | if (__tmp != 0) |
437 | __tmp->_M_weak_add_ref(); |
438 | if (_M_pi != 0) |
439 | _M_pi->_M_weak_release(); |
440 | _M_pi = __tmp; |
441 | return *this; |
442 | } |
443 | |
444 | __weak_count<_Lp>& |
445 | operator=(const __weak_count<_Lp>& __r) // nothrow |
446 | { |
447 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
448 | if (__tmp != 0) |
449 | __tmp->_M_weak_add_ref(); |
450 | if (_M_pi != 0) |
451 | _M_pi->_M_weak_release(); |
452 | _M_pi = __tmp; |
453 | return *this; |
454 | } |
455 | |
456 | void |
457 | _M_swap(__weak_count<_Lp>& __r) // nothrow |
458 | { |
459 | _Sp_counted_base<_Lp>* __tmp = __r._M_pi; |
460 | __r._M_pi = _M_pi; |
461 | _M_pi = __tmp; |
462 | } |
463 | |
464 | long |
465 | _M_get_use_count() const // nothrow |
466 | { return _M_pi != 0 ? _M_pi->_M_get_use_count() : 0; } |
467 | |
468 | friend inline bool |
469 | operator==(const __weak_count<_Lp>& __a, const __weak_count<_Lp>& __b) |
470 | { return __a._M_pi == __b._M_pi; } |
471 | |
472 | friend inline bool |
473 | operator<(const __weak_count<_Lp>& __a, const __weak_count<_Lp>& __b) |
474 | { return std::less<_Sp_counted_base<_Lp>*>()(__a._M_pi, __b._M_pi); } |
475 | |
476 | private: |
477 | friend class __shared_count<_Lp>; |
478 | |
479 | _Sp_counted_base<_Lp>* _M_pi; |
480 | }; |
481 | |
482 | // now that __weak_count is defined we can define this constructor: |
483 | template<_Lock_policy _Lp> |
484 | inline |
485 | __shared_count<_Lp>:: |
486 | __shared_count(const __weak_count<_Lp>& __r) |
487 | : _M_pi(__r._M_pi) |
488 | { |
489 | if (_M_pi != 0) |
490 | _M_pi->_M_add_ref_lock(); |
491 | else |
492 | __throw_bad_weak_ptr(); |
493 | } |
494 | |
495 | // Forward declarations. |
496 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> |
497 | class __shared_ptr; |
498 | |
499 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> |
500 | class __weak_ptr; |
501 | |
502 | template<typename _Tp, _Lock_policy _Lp = __default_lock_policy> |
503 | class __enable_shared_from_this; |
504 | |
505 | template<typename _Tp> |
506 | class shared_ptr; |
507 | |
508 | template<typename _Tp> |
509 | class weak_ptr; |
510 | |
511 | template<typename _Tp> |
512 | class enable_shared_from_this; |
513 | |
514 | // Support for enable_shared_from_this. |
515 | |
516 | // Friend of __enable_shared_from_this. |
517 | template<_Lock_policy _Lp, typename _Tp1, typename _Tp2> |
518 | void |
519 | __enable_shared_from_this_helper(const __shared_count<_Lp>&, |
520 | const __enable_shared_from_this<_Tp1, |
521 | _Lp>*, const _Tp2*); |
522 | |
523 | // Friend of enable_shared_from_this. |
524 | template<typename _Tp1, typename _Tp2> |
525 | void |
526 | __enable_shared_from_this_helper(const __shared_count<>&, |
527 | const enable_shared_from_this<_Tp1>*, |
528 | const _Tp2*); |
529 | |
530 | template<_Lock_policy _Lp> |
531 | inline void |
532 | __enable_shared_from_this_helper(const __shared_count<_Lp>&, ...) |
533 | { } |
534 | |
535 | |
536 | struct __static_cast_tag { }; |
537 | struct __const_cast_tag { }; |
538 | struct __dynamic_cast_tag { }; |
539 | |
540 | // A smart pointer with reference-counted copy semantics. The |
541 | // object pointed to is deleted when the last shared_ptr pointing to |
542 | // it is destroyed or reset. |
543 | template<typename _Tp, _Lock_policy _Lp> |
544 | class __shared_ptr |
545 | { |
546 | public: |
547 | typedef _Tp element_type; |
548 | |
549 | __shared_ptr() |
550 | : _M_ptr(0), _M_refcount() // never throws |
551 | { } |
552 | |
553 | template<typename _Tp1> |
554 | explicit |
555 | __shared_ptr(_Tp1* __p) |
556 | : _M_ptr(__p), _M_refcount(__p) |
557 | { |
558 | __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) |
559 | typedef int _IsComplete[sizeof(_Tp1)]; |
560 | __enable_shared_from_this_helper(_M_refcount, __p, __p); |
561 | } |
562 | |
563 | template<typename _Tp1, typename _Deleter> |
564 | __shared_ptr(_Tp1* __p, _Deleter __d) |
565 | : _M_ptr(__p), _M_refcount(__p, __d) |
566 | { |
567 | __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) |
568 | // TODO requires _Deleter CopyConstructible and __d(__p) well-formed |
569 | __enable_shared_from_this_helper(_M_refcount, __p, __p); |
570 | } |
571 | |
572 | // generated copy constructor, assignment, destructor are fine. |
573 | |
574 | template<typename _Tp1> |
575 | __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r) |
576 | : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws |
577 | { __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) } |
578 | |
579 | template<typename _Tp1> |
580 | explicit |
581 | __shared_ptr(const __weak_ptr<_Tp1, _Lp>& __r) |
582 | : _M_refcount(__r._M_refcount) // may throw |
583 | { |
584 | __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) |
585 | // It is now safe to copy __r._M_ptr, as _M_refcount(__r._M_refcount) |
586 | // did not throw. |
587 | _M_ptr = __r._M_ptr; |
588 | } |
589 | |
590 | #if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED |
591 | #pragma GCC diagnostic push |
592 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
593 | // Postcondition: use_count() == 1 and __r.get() == 0 |
594 | template<typename _Tp1> |
595 | explicit |
596 | __shared_ptr(std::auto_ptr<_Tp1>& __r) |
597 | : _M_ptr(__r.get()), _M_refcount() |
598 | { // TODO requries delete __r.release() well-formed |
599 | __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) |
600 | typedef int _IsComplete[sizeof(_Tp1)]; |
601 | _Tp1* __tmp = __r.get(); |
602 | _M_refcount = __shared_count<_Lp>(__r); |
603 | __enable_shared_from_this_helper(_M_refcount, __tmp, __tmp); |
604 | } |
605 | #pragma GCC diagnostic pop |
606 | #endif |
607 | |
608 | template<typename _Tp1> |
609 | __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, __static_cast_tag) |
610 | : _M_ptr(static_cast<element_type*>(__r._M_ptr)), |
611 | _M_refcount(__r._M_refcount) |
612 | { } |
613 | |
614 | template<typename _Tp1> |
615 | __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, __const_cast_tag) |
616 | : _M_ptr(const_cast<element_type*>(__r._M_ptr)), |
617 | _M_refcount(__r._M_refcount) |
618 | { } |
619 | |
620 | template<typename _Tp1> |
621 | __shared_ptr(const __shared_ptr<_Tp1, _Lp>& __r, __dynamic_cast_tag) |
622 | : _M_ptr(dynamic_cast<element_type*>(__r._M_ptr)), |
623 | _M_refcount(__r._M_refcount) |
624 | { |
625 | if (_M_ptr == 0) // need to allocate new counter -- the cast failed |
626 | _M_refcount = __shared_count<_Lp>(); |
627 | } |
628 | |
629 | template<typename _Tp1> |
630 | __shared_ptr& |
631 | operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws |
632 | { |
633 | _M_ptr = __r._M_ptr; |
634 | _M_refcount = __r._M_refcount; // __shared_count::op= doesn't throw |
635 | return *this; |
636 | } |
637 | |
638 | #if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED |
639 | #pragma GCC diagnostic push |
640 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
641 | template<typename _Tp1> |
642 | __shared_ptr& |
643 | operator=(std::auto_ptr<_Tp1>& __r) |
644 | { |
645 | __shared_ptr(__r).swap(*this); |
646 | return *this; |
647 | } |
648 | #pragma GCC diagnostic pop |
649 | #endif |
650 | |
651 | void |
652 | reset() // never throws |
653 | { __shared_ptr().swap(*this); } |
654 | |
655 | template<typename _Tp1> |
656 | void |
657 | reset(_Tp1* __p) // _Tp1 must be complete. |
658 | { |
659 | // Catch self-reset errors. |
660 | _GLIBCXX_DEBUG_ASSERT(__p == 0 || __p != _M_ptr); |
661 | __shared_ptr(__p).swap(*this); |
662 | } |
663 | |
664 | template<typename _Tp1, typename _Deleter> |
665 | void |
666 | reset(_Tp1* __p, _Deleter __d) |
667 | { __shared_ptr(__p, __d).swap(*this); } |
668 | |
669 | // Allow class instantiation when _Tp is [cv-qual] void. |
670 | typename std::tr1::add_reference<_Tp>::type |
671 | operator*() const // never throws |
672 | { |
673 | _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); |
674 | return *_M_ptr; |
675 | } |
676 | |
677 | _Tp* |
678 | operator->() const // never throws |
679 | { |
680 | _GLIBCXX_DEBUG_ASSERT(_M_ptr != 0); |
681 | return _M_ptr; |
682 | } |
683 | |
684 | _Tp* |
685 | get() const // never throws |
686 | { return _M_ptr; } |
687 | |
688 | // Implicit conversion to "bool" |
689 | private: |
690 | typedef _Tp* __shared_ptr::*__unspecified_bool_type; |
691 | |
692 | public: |
693 | operator __unspecified_bool_type() const // never throws |
694 | { return _M_ptr == 0 ? 0 : &__shared_ptr::_M_ptr; } |
695 | |
696 | bool |
697 | unique() const // never throws |
698 | { return _M_refcount._M_unique(); } |
699 | |
700 | long |
701 | use_count() const // never throws |
702 | { return _M_refcount._M_get_use_count(); } |
703 | |
704 | void |
705 | swap(__shared_ptr<_Tp, _Lp>& __other) // never throws |
706 | { |
707 | std::swap(_M_ptr, __other._M_ptr); |
708 | _M_refcount._M_swap(__other._M_refcount); |
709 | } |
710 | |
711 | private: |
712 | void* |
713 | _M_get_deleter(const std::type_info& __ti) const |
714 | { return _M_refcount._M_get_deleter(__ti); } |
715 | |
716 | template<typename _Tp1, _Lock_policy _Lp1> |
717 | bool |
718 | _M_less(const __shared_ptr<_Tp1, _Lp1>& __rhs) const |
719 | { return _M_refcount < __rhs._M_refcount; } |
720 | |
721 | template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; |
722 | template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; |
723 | |
724 | template<typename _Del, typename _Tp1, _Lock_policy _Lp1> |
725 | friend _Del* get_deleter(const __shared_ptr<_Tp1, _Lp1>&); |
726 | |
727 | // Friends injected into enclosing namespace and found by ADL: |
728 | template<typename _Tp1> |
729 | friend inline bool |
730 | operator==(const __shared_ptr& __a, const __shared_ptr<_Tp1, _Lp>& __b) |
731 | { return __a.get() == __b.get(); } |
732 | |
733 | template<typename _Tp1> |
734 | friend inline bool |
735 | operator!=(const __shared_ptr& __a, const __shared_ptr<_Tp1, _Lp>& __b) |
736 | { return __a.get() != __b.get(); } |
737 | |
738 | template<typename _Tp1> |
739 | friend inline bool |
740 | operator<(const __shared_ptr& __a, const __shared_ptr<_Tp1, _Lp>& __b) |
741 | { return __a._M_less(__b); } |
742 | |
743 | _Tp* _M_ptr; // Contained pointer. |
744 | __shared_count<_Lp> _M_refcount; // Reference counter. |
745 | }; |
746 | |
747 | // 2.2.3.8 shared_ptr specialized algorithms. |
748 | template<typename _Tp, _Lock_policy _Lp> |
749 | inline void |
750 | swap(__shared_ptr<_Tp, _Lp>& __a, __shared_ptr<_Tp, _Lp>& __b) |
751 | { __a.swap(__b); } |
752 | |
753 | // 2.2.3.9 shared_ptr casts |
754 | /* The seemingly equivalent |
755 | * shared_ptr<_Tp, _Lp>(static_cast<_Tp*>(__r.get())) |
756 | * will eventually result in undefined behaviour, |
757 | * attempting to delete the same object twice. |
758 | */ |
759 | template<typename _Tp, typename _Tp1, _Lock_policy _Lp> |
760 | inline __shared_ptr<_Tp, _Lp> |
761 | static_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) |
762 | { return __shared_ptr<_Tp, _Lp>(__r, __static_cast_tag()); } |
763 | |
764 | /* The seemingly equivalent |
765 | * shared_ptr<_Tp, _Lp>(const_cast<_Tp*>(__r.get())) |
766 | * will eventually result in undefined behaviour, |
767 | * attempting to delete the same object twice. |
768 | */ |
769 | template<typename _Tp, typename _Tp1, _Lock_policy _Lp> |
770 | inline __shared_ptr<_Tp, _Lp> |
771 | const_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) |
772 | { return __shared_ptr<_Tp, _Lp>(__r, __const_cast_tag()); } |
773 | |
774 | /* The seemingly equivalent |
775 | * shared_ptr<_Tp, _Lp>(dynamic_cast<_Tp*>(__r.get())) |
776 | * will eventually result in undefined behaviour, |
777 | * attempting to delete the same object twice. |
778 | */ |
779 | template<typename _Tp, typename _Tp1, _Lock_policy _Lp> |
780 | inline __shared_ptr<_Tp, _Lp> |
781 | dynamic_pointer_cast(const __shared_ptr<_Tp1, _Lp>& __r) |
782 | { return __shared_ptr<_Tp, _Lp>(__r, __dynamic_cast_tag()); } |
783 | |
784 | // 2.2.3.7 shared_ptr I/O |
785 | template<typename _Ch, typename _Tr, typename _Tp, _Lock_policy _Lp> |
786 | std::basic_ostream<_Ch, _Tr>& |
787 | operator<<(std::basic_ostream<_Ch, _Tr>& __os, |
788 | const __shared_ptr<_Tp, _Lp>& __p) |
789 | { |
790 | __os << __p.get(); |
791 | return __os; |
792 | } |
793 | |
794 | // 2.2.3.10 shared_ptr get_deleter (experimental) |
795 | template<typename _Del, typename _Tp, _Lock_policy _Lp> |
796 | inline _Del* |
797 | get_deleter(const __shared_ptr<_Tp, _Lp>& __p) |
798 | { |
799 | #if __cpp_rtti |
800 | return static_cast<_Del*>(__p._M_get_deleter(typeid(_Del))); |
801 | #else |
802 | return 0; |
803 | #endif |
804 | } |
805 | |
806 | |
807 | template<typename _Tp, _Lock_policy _Lp> |
808 | class __weak_ptr |
809 | { |
810 | public: |
811 | typedef _Tp element_type; |
812 | |
813 | __weak_ptr() |
814 | : _M_ptr(0), _M_refcount() // never throws |
815 | { } |
816 | |
817 | // Generated copy constructor, assignment, destructor are fine. |
818 | |
819 | // The "obvious" converting constructor implementation: |
820 | // |
821 | // template<typename _Tp1> |
822 | // __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r) |
823 | // : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws |
824 | // { } |
825 | // |
826 | // has a serious problem. |
827 | // |
828 | // __r._M_ptr may already have been invalidated. The _M_ptr(__r._M_ptr) |
829 | // conversion may require access to *__r._M_ptr (virtual inheritance). |
830 | // |
831 | // It is not possible to avoid spurious access violations since |
832 | // in multithreaded programs __r._M_ptr may be invalidated at any point. |
833 | template<typename _Tp1> |
834 | __weak_ptr(const __weak_ptr<_Tp1, _Lp>& __r) |
835 | : _M_refcount(__r._M_refcount) // never throws |
836 | { |
837 | __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) |
838 | _M_ptr = __r.lock().get(); |
839 | } |
840 | |
841 | template<typename _Tp1> |
842 | __weak_ptr(const __shared_ptr<_Tp1, _Lp>& __r) |
843 | : _M_ptr(__r._M_ptr), _M_refcount(__r._M_refcount) // never throws |
844 | { __glibcxx_function_requires(_ConvertibleConcept<_Tp1*, _Tp*>) } |
845 | |
846 | template<typename _Tp1> |
847 | __weak_ptr& |
848 | operator=(const __weak_ptr<_Tp1, _Lp>& __r) // never throws |
849 | { |
850 | _M_ptr = __r.lock().get(); |
851 | _M_refcount = __r._M_refcount; |
852 | return *this; |
853 | } |
854 | |
855 | template<typename _Tp1> |
856 | __weak_ptr& |
857 | operator=(const __shared_ptr<_Tp1, _Lp>& __r) // never throws |
858 | { |
859 | _M_ptr = __r._M_ptr; |
860 | _M_refcount = __r._M_refcount; |
861 | return *this; |
862 | } |
863 | |
864 | __shared_ptr<_Tp, _Lp> |
865 | lock() const // never throws |
866 | { |
867 | #ifdef __GTHREADS |
868 | // Optimization: avoid throw overhead. |
869 | if (expired()) |
870 | return __shared_ptr<element_type, _Lp>(); |
871 | |
872 | __try |
873 | { |
874 | return __shared_ptr<element_type, _Lp>(*this); |
875 | } |
876 | __catch(const bad_weak_ptr&) |
877 | { |
878 | // Q: How can we get here? |
879 | // A: Another thread may have invalidated r after the |
880 | // use_count test above. |
881 | return __shared_ptr<element_type, _Lp>(); |
882 | } |
883 | |
884 | #else |
885 | // Optimization: avoid try/catch overhead when single threaded. |
886 | return expired() ? __shared_ptr<element_type, _Lp>() |
887 | : __shared_ptr<element_type, _Lp>(*this); |
888 | |
889 | #endif |
890 | } // XXX MT |
891 | |
892 | long |
893 | use_count() const // never throws |
894 | { return _M_refcount._M_get_use_count(); } |
895 | |
896 | bool |
897 | expired() const // never throws |
898 | { return _M_refcount._M_get_use_count() == 0; } |
899 | |
900 | void |
901 | reset() // never throws |
902 | { __weak_ptr().swap(*this); } |
903 | |
904 | void |
905 | swap(__weak_ptr& __s) // never throws |
906 | { |
907 | std::swap(_M_ptr, __s._M_ptr); |
908 | _M_refcount._M_swap(__s._M_refcount); |
909 | } |
910 | |
911 | private: |
912 | // Used by __enable_shared_from_this. |
913 | void |
914 | _M_assign(_Tp* __ptr, const __shared_count<_Lp>& __refcount) |
915 | { |
916 | _M_ptr = __ptr; |
917 | _M_refcount = __refcount; |
918 | } |
919 | |
920 | template<typename _Tp1> |
921 | bool |
922 | _M_less(const __weak_ptr<_Tp1, _Lp>& __rhs) const |
923 | { return _M_refcount < __rhs._M_refcount; } |
924 | |
925 | template<typename _Tp1, _Lock_policy _Lp1> friend class __shared_ptr; |
926 | template<typename _Tp1, _Lock_policy _Lp1> friend class __weak_ptr; |
927 | friend class __enable_shared_from_this<_Tp, _Lp>; |
928 | friend class enable_shared_from_this<_Tp>; |
929 | |
930 | // Friend injected into namespace and found by ADL. |
931 | template<typename _Tp1> |
932 | friend inline bool |
933 | operator<(const __weak_ptr& __lhs, const __weak_ptr<_Tp1, _Lp>& __rhs) |
934 | { return __lhs._M_less(__rhs); } |
935 | |
936 | _Tp* _M_ptr; // Contained pointer. |
937 | __weak_count<_Lp> _M_refcount; // Reference counter. |
938 | }; |
939 | |
940 | // 2.2.4.7 weak_ptr specialized algorithms. |
941 | template<typename _Tp, _Lock_policy _Lp> |
942 | inline void |
943 | swap(__weak_ptr<_Tp, _Lp>& __a, __weak_ptr<_Tp, _Lp>& __b) |
944 | { __a.swap(__b); } |
945 | |
946 | |
947 | template<typename _Tp, _Lock_policy _Lp> |
948 | class __enable_shared_from_this |
949 | { |
950 | protected: |
951 | __enable_shared_from_this() { } |
952 | |
953 | __enable_shared_from_this(const __enable_shared_from_this&) { } |
954 | |
955 | __enable_shared_from_this& |
956 | operator=(const __enable_shared_from_this&) |
957 | { return *this; } |
958 | |
959 | ~__enable_shared_from_this() { } |
960 | |
961 | public: |
962 | __shared_ptr<_Tp, _Lp> |
963 | shared_from_this() |
964 | { return __shared_ptr<_Tp, _Lp>(this->_M_weak_this); } |
965 | |
966 | __shared_ptr<const _Tp, _Lp> |
967 | shared_from_this() const |
968 | { return __shared_ptr<const _Tp, _Lp>(this->_M_weak_this); } |
969 | |
970 | private: |
971 | template<typename _Tp1> |
972 | void |
973 | _M_weak_assign(_Tp1* __p, const __shared_count<_Lp>& __n) const |
974 | { _M_weak_this._M_assign(__p, __n); } |
975 | |
976 | template<typename _Tp1> |
977 | friend void |
978 | __enable_shared_from_this_helper(const __shared_count<_Lp>& __pn, |
979 | const __enable_shared_from_this* __pe, |
980 | const _Tp1* __px) |
981 | { |
982 | if (__pe != 0) |
983 | __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn); |
984 | } |
985 | |
986 | mutable __weak_ptr<_Tp, _Lp> _M_weak_this; |
987 | }; |
988 | |
989 | |
990 | // The actual shared_ptr, with forwarding constructors and |
991 | // assignment operators. |
992 | template<typename _Tp> |
993 | class shared_ptr |
994 | : public __shared_ptr<_Tp> |
995 | { |
996 | public: |
997 | shared_ptr() |
998 | : __shared_ptr<_Tp>() { } |
999 | |
1000 | template<typename _Tp1> |
1001 | explicit |
1002 | shared_ptr(_Tp1* __p) |
1003 | : __shared_ptr<_Tp>(__p) { } |
1004 | |
1005 | template<typename _Tp1, typename _Deleter> |
1006 | shared_ptr(_Tp1* __p, _Deleter __d) |
1007 | : __shared_ptr<_Tp>(__p, __d) { } |
1008 | |
1009 | template<typename _Tp1> |
1010 | shared_ptr(const shared_ptr<_Tp1>& __r) |
1011 | : __shared_ptr<_Tp>(__r) { } |
1012 | |
1013 | template<typename _Tp1> |
1014 | explicit |
1015 | shared_ptr(const weak_ptr<_Tp1>& __r) |
1016 | : __shared_ptr<_Tp>(__r) { } |
1017 | |
1018 | #if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED |
1019 | #pragma GCC diagnostic push |
1020 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
1021 | template<typename _Tp1> |
1022 | explicit |
1023 | shared_ptr(std::auto_ptr<_Tp1>& __r) |
1024 | : __shared_ptr<_Tp>(__r) { } |
1025 | #pragma GCC diagnostic pop |
1026 | #endif |
1027 | |
1028 | template<typename _Tp1> |
1029 | shared_ptr(const shared_ptr<_Tp1>& __r, __static_cast_tag) |
1030 | : __shared_ptr<_Tp>(__r, __static_cast_tag()) { } |
1031 | |
1032 | template<typename _Tp1> |
1033 | shared_ptr(const shared_ptr<_Tp1>& __r, __const_cast_tag) |
1034 | : __shared_ptr<_Tp>(__r, __const_cast_tag()) { } |
1035 | |
1036 | template<typename _Tp1> |
1037 | shared_ptr(const shared_ptr<_Tp1>& __r, __dynamic_cast_tag) |
1038 | : __shared_ptr<_Tp>(__r, __dynamic_cast_tag()) { } |
1039 | |
1040 | template<typename _Tp1> |
1041 | shared_ptr& |
1042 | operator=(const shared_ptr<_Tp1>& __r) // never throws |
1043 | { |
1044 | this->__shared_ptr<_Tp>::operator=(__r); |
1045 | return *this; |
1046 | } |
1047 | |
1048 | #if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED |
1049 | #pragma GCC diagnostic push |
1050 | #pragma GCC diagnostic ignored "-Wdeprecated-declarations" |
1051 | template<typename _Tp1> |
1052 | shared_ptr& |
1053 | operator=(std::auto_ptr<_Tp1>& __r) |
1054 | { |
1055 | this->__shared_ptr<_Tp>::operator=(__r); |
1056 | return *this; |
1057 | } |
1058 | #pragma GCC diagnostic pop |
1059 | #endif |
1060 | }; |
1061 | |
1062 | // 2.2.3.8 shared_ptr specialized algorithms. |
1063 | template<typename _Tp> |
1064 | inline void |
1065 | swap(__shared_ptr<_Tp>& __a, __shared_ptr<_Tp>& __b) |
1066 | { __a.swap(__b); } |
1067 | |
1068 | template<typename _Tp, typename _Tp1> |
1069 | inline shared_ptr<_Tp> |
1070 | static_pointer_cast(const shared_ptr<_Tp1>& __r) |
1071 | { return shared_ptr<_Tp>(__r, __static_cast_tag()); } |
1072 | |
1073 | template<typename _Tp, typename _Tp1> |
1074 | inline shared_ptr<_Tp> |
1075 | const_pointer_cast(const shared_ptr<_Tp1>& __r) |
1076 | { return shared_ptr<_Tp>(__r, __const_cast_tag()); } |
1077 | |
1078 | template<typename _Tp, typename _Tp1> |
1079 | inline shared_ptr<_Tp> |
1080 | dynamic_pointer_cast(const shared_ptr<_Tp1>& __r) |
1081 | { return shared_ptr<_Tp>(__r, __dynamic_cast_tag()); } |
1082 | |
1083 | |
1084 | // The actual weak_ptr, with forwarding constructors and |
1085 | // assignment operators. |
1086 | template<typename _Tp> |
1087 | class weak_ptr |
1088 | : public __weak_ptr<_Tp> |
1089 | { |
1090 | public: |
1091 | weak_ptr() |
1092 | : __weak_ptr<_Tp>() { } |
1093 | |
1094 | template<typename _Tp1> |
1095 | weak_ptr(const weak_ptr<_Tp1>& __r) |
1096 | : __weak_ptr<_Tp>(__r) { } |
1097 | |
1098 | template<typename _Tp1> |
1099 | weak_ptr(const shared_ptr<_Tp1>& __r) |
1100 | : __weak_ptr<_Tp>(__r) { } |
1101 | |
1102 | template<typename _Tp1> |
1103 | weak_ptr& |
1104 | operator=(const weak_ptr<_Tp1>& __r) // never throws |
1105 | { |
1106 | this->__weak_ptr<_Tp>::operator=(__r); |
1107 | return *this; |
1108 | } |
1109 | |
1110 | template<typename _Tp1> |
1111 | weak_ptr& |
1112 | operator=(const shared_ptr<_Tp1>& __r) // never throws |
1113 | { |
1114 | this->__weak_ptr<_Tp>::operator=(__r); |
1115 | return *this; |
1116 | } |
1117 | |
1118 | shared_ptr<_Tp> |
1119 | lock() const // never throws |
1120 | { |
1121 | #ifdef __GTHREADS |
1122 | if (this->expired()) |
1123 | return shared_ptr<_Tp>(); |
1124 | |
1125 | __try |
1126 | { |
1127 | return shared_ptr<_Tp>(*this); |
1128 | } |
1129 | __catch(const bad_weak_ptr&) |
1130 | { |
1131 | return shared_ptr<_Tp>(); |
1132 | } |
1133 | #else |
1134 | return this->expired() ? shared_ptr<_Tp>() |
1135 | : shared_ptr<_Tp>(*this); |
1136 | #endif |
1137 | } |
1138 | }; |
1139 | |
1140 | template<typename _Tp> |
1141 | class enable_shared_from_this |
1142 | { |
1143 | protected: |
1144 | enable_shared_from_this() { } |
1145 | |
1146 | enable_shared_from_this(const enable_shared_from_this&) { } |
1147 | |
1148 | enable_shared_from_this& |
1149 | operator=(const enable_shared_from_this&) |
1150 | { return *this; } |
1151 | |
1152 | ~enable_shared_from_this() { } |
1153 | |
1154 | public: |
1155 | shared_ptr<_Tp> |
1156 | shared_from_this() |
1157 | { return shared_ptr<_Tp>(this->_M_weak_this); } |
1158 | |
1159 | shared_ptr<const _Tp> |
1160 | shared_from_this() const |
1161 | { return shared_ptr<const _Tp>(this->_M_weak_this); } |
1162 | |
1163 | private: |
1164 | template<typename _Tp1> |
1165 | void |
1166 | _M_weak_assign(_Tp1* __p, const __shared_count<>& __n) const |
1167 | { _M_weak_this._M_assign(__p, __n); } |
1168 | |
1169 | template<typename _Tp1> |
1170 | friend void |
1171 | __enable_shared_from_this_helper(const __shared_count<>& __pn, |
1172 | const enable_shared_from_this* __pe, |
1173 | const _Tp1* __px) |
1174 | { |
1175 | if (__pe != 0) |
1176 | __pe->_M_weak_assign(const_cast<_Tp1*>(__px), __pn); |
1177 | } |
1178 | |
1179 | mutable weak_ptr<_Tp> _M_weak_this; |
1180 | }; |
1181 | } |
1182 | |
1183 | _GLIBCXX_END_NAMESPACE_VERSION |
1184 | } |
1185 | |
1186 | #endif // _TR1_SHARED_PTR_H |
1187 | |