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1 | // <tr1/shared_ptr.h> -*- C++ -*- | |
2 | ||
3 | // Copyright (C) 2007-2024 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(&_M_use_count, 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(&_M_use_count, -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(&_M_weak_count, | |
154 | -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(&_M_weak_count, 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(&_M_weak_count, -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(&_M_use_count, 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(&_M_use_count, 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 |