1// unique_ptr implementation -*- C++ -*-
2
3// Copyright (C) 2008-2021 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/** @file bits/unique_ptr.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{memory}
28 */
29
30#ifndef _UNIQUE_PTR_H
31#define _UNIQUE_PTR_H 1
32
33#include <bits/c++config.h>
34#include <debug/assertions.h>
35#include <type_traits>
36#include <utility>
37#include <tuple>
38#include <bits/stl_function.h>
39#include <bits/functional_hash.h>
40#if __cplusplus > 201703L
41# include <compare>
42# include <ostream>
43#endif
44
45namespace std _GLIBCXX_VISIBILITY(default)
46{
47_GLIBCXX_BEGIN_NAMESPACE_VERSION
48
49 /**
50 * @addtogroup pointer_abstractions
51 * @{
52 */
53
54#if _GLIBCXX_USE_DEPRECATED
55#pragma GCC diagnostic push
56#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
57 template<typename> class auto_ptr;
58#pragma GCC diagnostic pop
59#endif
60
61 /// Primary template of default_delete, used by unique_ptr for single objects
62 template<typename _Tp>
63 struct default_delete
64 {
65 /// Default constructor
66 constexpr default_delete() noexcept = default;
67
68 /** @brief Converting constructor.
69 *
70 * Allows conversion from a deleter for objects of another type, `_Up`,
71 * only if `_Up*` is convertible to `_Tp*`.
72 */
73 template<typename _Up,
74 typename = _Require<is_convertible<_Up*, _Tp*>>>
75 default_delete(const default_delete<_Up>&) noexcept { }
76
77 /// Calls `delete __ptr`
78 void
79 operator()(_Tp* __ptr) const
80 {
81 static_assert(!is_void<_Tp>::value,
82 "can't delete pointer to incomplete type");
83 static_assert(sizeof(_Tp)>0,
84 "can't delete pointer to incomplete type");
85 delete __ptr;
86 }
87 };
88
89 // _GLIBCXX_RESOLVE_LIB_DEFECTS
90 // DR 740 - omit specialization for array objects with a compile time length
91
92 /// Specialization of default_delete for arrays, used by `unique_ptr<T[]>`
93 template<typename _Tp>
94 struct default_delete<_Tp[]>
95 {
96 public:
97 /// Default constructor
98 constexpr default_delete() noexcept = default;
99
100 /** @brief Converting constructor.
101 *
102 * Allows conversion from a deleter for arrays of another type, such as
103 * a const-qualified version of `_Tp`.
104 *
105 * Conversions from types derived from `_Tp` are not allowed because
106 * it is undefined to `delete[]` an array of derived types through a
107 * pointer to the base type.
108 */
109 template<typename _Up,
110 typename = _Require<is_convertible<_Up(*)[], _Tp(*)[]>>>
111 default_delete(const default_delete<_Up[]>&) noexcept { }
112
113 /// Calls `delete[] __ptr`
114 template<typename _Up>
115 typename enable_if<is_convertible<_Up(*)[], _Tp(*)[]>::value>::type
116 operator()(_Up* __ptr) const
117 {
118 static_assert(sizeof(_Tp)>0,
119 "can't delete pointer to incomplete type");
120 delete [] __ptr;
121 }
122 };
123
124 /// @cond undocumented
125
126 // Manages the pointer and deleter of a unique_ptr
127 template <typename _Tp, typename _Dp>
128 class __uniq_ptr_impl
129 {
130 template <typename _Up, typename _Ep, typename = void>
131 struct _Ptr
132 {
133 using type = _Up*;
134 };
135
136 template <typename _Up, typename _Ep>
137 struct
138 _Ptr<_Up, _Ep, __void_t<typename remove_reference<_Ep>::type::pointer>>
139 {
140 using type = typename remove_reference<_Ep>::type::pointer;
141 };
142
143 public:
144 using _DeleterConstraint = enable_if<
145 __and_<__not_<is_pointer<_Dp>>,
146 is_default_constructible<_Dp>>::value>;
147
148 using pointer = typename _Ptr<_Tp, _Dp>::type;
149
150 static_assert( !is_rvalue_reference<_Dp>::value,
151 "unique_ptr's deleter type must be a function object type"
152 " or an lvalue reference type" );
153
154 __uniq_ptr_impl() = default;
155 __uniq_ptr_impl(pointer __p) : _M_t() { _M_ptr() = __p; }
156
157 template<typename _Del>
158 __uniq_ptr_impl(pointer __p, _Del&& __d)
159 : _M_t(__p, std::forward<_Del>(__d)) { }
160
161 __uniq_ptr_impl(__uniq_ptr_impl&& __u) noexcept
162 : _M_t(std::move(__u._M_t))
163 { __u._M_ptr() = nullptr; }
164
165 __uniq_ptr_impl& operator=(__uniq_ptr_impl&& __u) noexcept
166 {
167 reset(__u.release());
168 _M_deleter() = std::forward<_Dp>(__u._M_deleter());
169 return *this;
170 }
171
172 pointer& _M_ptr() { return std::get<0>(_M_t); }
173 pointer _M_ptr() const { return std::get<0>(_M_t); }
174 _Dp& _M_deleter() { return std::get<1>(_M_t); }
175 const _Dp& _M_deleter() const { return std::get<1>(_M_t); }
176
177 void reset(pointer __p) noexcept
178 {
179 const pointer __old_p = _M_ptr();
180 _M_ptr() = __p;
181 if (__old_p)
182 _M_deleter()(__old_p);
183 }
184
185 pointer release() noexcept
186 {
187 pointer __p = _M_ptr();
188 _M_ptr() = nullptr;
189 return __p;
190 }
191
192 void
193 swap(__uniq_ptr_impl& __rhs) noexcept
194 {
195 using std::swap;
196 swap(this->_M_ptr(), __rhs._M_ptr());
197 swap(this->_M_deleter(), __rhs._M_deleter());
198 }
199
200 private:
201 tuple<pointer, _Dp> _M_t;
202 };
203
204 // Defines move construction + assignment as either defaulted or deleted.
205 template <typename _Tp, typename _Dp,
206 bool = is_move_constructible<_Dp>::value,
207 bool = is_move_assignable<_Dp>::value>
208 struct __uniq_ptr_data : __uniq_ptr_impl<_Tp, _Dp>
209 {
210 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
211 __uniq_ptr_data(__uniq_ptr_data&&) = default;
212 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = default;
213 };
214
215 template <typename _Tp, typename _Dp>
216 struct __uniq_ptr_data<_Tp, _Dp, true, false> : __uniq_ptr_impl<_Tp, _Dp>
217 {
218 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
219 __uniq_ptr_data(__uniq_ptr_data&&) = default;
220 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = delete;
221 };
222
223 template <typename _Tp, typename _Dp>
224 struct __uniq_ptr_data<_Tp, _Dp, false, true> : __uniq_ptr_impl<_Tp, _Dp>
225 {
226 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
227 __uniq_ptr_data(__uniq_ptr_data&&) = delete;
228 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = default;
229 };
230
231 template <typename _Tp, typename _Dp>
232 struct __uniq_ptr_data<_Tp, _Dp, false, false> : __uniq_ptr_impl<_Tp, _Dp>
233 {
234 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
235 __uniq_ptr_data(__uniq_ptr_data&&) = delete;
236 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = delete;
237 };
238 /// @endcond
239
240 /// 20.7.1.2 unique_ptr for single objects.
241 template <typename _Tp, typename _Dp = default_delete<_Tp>>
242 class unique_ptr
243 {
244 template <typename _Up>
245 using _DeleterConstraint =
246 typename __uniq_ptr_impl<_Tp, _Up>::_DeleterConstraint::type;
247
248 __uniq_ptr_data<_Tp, _Dp> _M_t;
249
250 public:
251 using pointer = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
252 using element_type = _Tp;
253 using deleter_type = _Dp;
254
255 private:
256 // helper template for detecting a safe conversion from another
257 // unique_ptr
258 template<typename _Up, typename _Ep>
259 using __safe_conversion_up = __and_<
260 is_convertible<typename unique_ptr<_Up, _Ep>::pointer, pointer>,
261 __not_<is_array<_Up>>
262 >;
263
264 public:
265 // Constructors.
266
267 /// Default constructor, creates a unique_ptr that owns nothing.
268 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
269 constexpr unique_ptr() noexcept
270 : _M_t()
271 { }
272
273 /** Takes ownership of a pointer.
274 *
275 * @param __p A pointer to an object of @c element_type
276 *
277 * The deleter will be value-initialized.
278 */
279 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
280 explicit
281 unique_ptr(pointer __p) noexcept
282 : _M_t(__p)
283 { }
284
285 /** Takes ownership of a pointer.
286 *
287 * @param __p A pointer to an object of @c element_type
288 * @param __d A reference to a deleter.
289 *
290 * The deleter will be initialized with @p __d
291 */
292 template<typename _Del = deleter_type,
293 typename = _Require<is_copy_constructible<_Del>>>
294 unique_ptr(pointer __p, const deleter_type& __d) noexcept
295 : _M_t(__p, __d) { }
296
297 /** Takes ownership of a pointer.
298 *
299 * @param __p A pointer to an object of @c element_type
300 * @param __d An rvalue reference to a (non-reference) deleter.
301 *
302 * The deleter will be initialized with @p std::move(__d)
303 */
304 template<typename _Del = deleter_type,
305 typename = _Require<is_move_constructible<_Del>>>
306 unique_ptr(pointer __p,
307 __enable_if_t<!is_lvalue_reference<_Del>::value,
308 _Del&&> __d) noexcept
309 : _M_t(__p, std::move(__d))
310 { }
311
312 template<typename _Del = deleter_type,
313 typename _DelUnref = typename remove_reference<_Del>::type>
314 unique_ptr(pointer,
315 __enable_if_t<is_lvalue_reference<_Del>::value,
316 _DelUnref&&>) = delete;
317
318 /// Creates a unique_ptr that owns nothing.
319 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
320 constexpr unique_ptr(nullptr_t) noexcept
321 : _M_t()
322 { }
323
324 // Move constructors.
325
326 /// Move constructor.
327 unique_ptr(unique_ptr&&) = default;
328
329 /** @brief Converting constructor from another type
330 *
331 * Requires that the pointer owned by @p __u is convertible to the
332 * type of pointer owned by this object, @p __u does not own an array,
333 * and @p __u has a compatible deleter type.
334 */
335 template<typename _Up, typename _Ep, typename = _Require<
336 __safe_conversion_up<_Up, _Ep>,
337 typename conditional<is_reference<_Dp>::value,
338 is_same<_Ep, _Dp>,
339 is_convertible<_Ep, _Dp>>::type>>
340 unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
341 : _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
342 { }
343
344#if _GLIBCXX_USE_DEPRECATED
345#pragma GCC diagnostic push
346#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
347 /// Converting constructor from @c auto_ptr
348 template<typename _Up, typename = _Require<
349 is_convertible<_Up*, _Tp*>, is_same<_Dp, default_delete<_Tp>>>>
350 unique_ptr(auto_ptr<_Up>&& __u) noexcept;
351#pragma GCC diagnostic pop
352#endif
353
354 /// Destructor, invokes the deleter if the stored pointer is not null.
355 ~unique_ptr() noexcept
356 {
357 static_assert(__is_invocable<deleter_type&, pointer>::value,
358 "unique_ptr's deleter must be invocable with a pointer");
359 auto& __ptr = _M_t._M_ptr();
360 if (__ptr != nullptr)
361 get_deleter()(std::move(__ptr));
362 __ptr = pointer();
363 }
364
365 // Assignment.
366
367 /** @brief Move assignment operator.
368 *
369 * Invokes the deleter if this object owns a pointer.
370 */
371 unique_ptr& operator=(unique_ptr&&) = default;
372
373 /** @brief Assignment from another type.
374 *
375 * @param __u The object to transfer ownership from, which owns a
376 * convertible pointer to a non-array object.
377 *
378 * Invokes the deleter if this object owns a pointer.
379 */
380 template<typename _Up, typename _Ep>
381 typename enable_if< __and_<
382 __safe_conversion_up<_Up, _Ep>,
383 is_assignable<deleter_type&, _Ep&&>
384 >::value,
385 unique_ptr&>::type
386 operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
387 {
388 reset(__u.release());
389 get_deleter() = std::forward<_Ep>(__u.get_deleter());
390 return *this;
391 }
392
393 /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
394 unique_ptr&
395 operator=(nullptr_t) noexcept
396 {
397 reset();
398 return *this;
399 }
400
401 // Observers.
402
403 /// Dereference the stored pointer.
404 typename add_lvalue_reference<element_type>::type
405 operator*() const
406 {
407 __glibcxx_assert(get() != pointer());
408 return *get();
409 }
410
411 /// Return the stored pointer.
412 pointer
413 operator->() const noexcept
414 {
415 _GLIBCXX_DEBUG_PEDASSERT(get() != pointer());
416 return get();
417 }
418
419 /// Return the stored pointer.
420 pointer
421 get() const noexcept
422 { return _M_t._M_ptr(); }
423
424 /// Return a reference to the stored deleter.
425 deleter_type&
426 get_deleter() noexcept
427 { return _M_t._M_deleter(); }
428
429 /// Return a reference to the stored deleter.
430 const deleter_type&
431 get_deleter() const noexcept
432 { return _M_t._M_deleter(); }
433
434 /// Return @c true if the stored pointer is not null.
435 explicit operator bool() const noexcept
436 { return get() == pointer() ? false : true; }
437
438 // Modifiers.
439
440 /// Release ownership of any stored pointer.
441 pointer
442 release() noexcept
443 { return _M_t.release(); }
444
445 /** @brief Replace the stored pointer.
446 *
447 * @param __p The new pointer to store.
448 *
449 * The deleter will be invoked if a pointer is already owned.
450 */
451 void
452 reset(pointer __p = pointer()) noexcept
453 {
454 static_assert(__is_invocable<deleter_type&, pointer>::value,
455 "unique_ptr's deleter must be invocable with a pointer");
456 _M_t.reset(std::move(__p));
457 }
458
459 /// Exchange the pointer and deleter with another object.
460 void
461 swap(unique_ptr& __u) noexcept
462 {
463 static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
464 _M_t.swap(__u._M_t);
465 }
466
467 // Disable copy from lvalue.
468 unique_ptr(const unique_ptr&) = delete;
469 unique_ptr& operator=(const unique_ptr&) = delete;
470 };
471
472 /// 20.7.1.3 unique_ptr for array objects with a runtime length
473 // [unique.ptr.runtime]
474 // _GLIBCXX_RESOLVE_LIB_DEFECTS
475 // DR 740 - omit specialization for array objects with a compile time length
476 template<typename _Tp, typename _Dp>
477 class unique_ptr<_Tp[], _Dp>
478 {
479 template <typename _Up>
480 using _DeleterConstraint =
481 typename __uniq_ptr_impl<_Tp, _Up>::_DeleterConstraint::type;
482
483 __uniq_ptr_data<_Tp, _Dp> _M_t;
484
485 template<typename _Up>
486 using __remove_cv = typename remove_cv<_Up>::type;
487
488 // like is_base_of<_Tp, _Up> but false if unqualified types are the same
489 template<typename _Up>
490 using __is_derived_Tp
491 = __and_< is_base_of<_Tp, _Up>,
492 __not_<is_same<__remove_cv<_Tp>, __remove_cv<_Up>>> >;
493
494 public:
495 using pointer = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
496 using element_type = _Tp;
497 using deleter_type = _Dp;
498
499 // helper template for detecting a safe conversion from another
500 // unique_ptr
501 template<typename _Up, typename _Ep,
502 typename _UPtr = unique_ptr<_Up, _Ep>,
503 typename _UP_pointer = typename _UPtr::pointer,
504 typename _UP_element_type = typename _UPtr::element_type>
505 using __safe_conversion_up = __and_<
506 is_array<_Up>,
507 is_same<pointer, element_type*>,
508 is_same<_UP_pointer, _UP_element_type*>,
509 is_convertible<_UP_element_type(*)[], element_type(*)[]>
510 >;
511
512 // helper template for detecting a safe conversion from a raw pointer
513 template<typename _Up>
514 using __safe_conversion_raw = __and_<
515 __or_<__or_<is_same<_Up, pointer>,
516 is_same<_Up, nullptr_t>>,
517 __and_<is_pointer<_Up>,
518 is_same<pointer, element_type*>,
519 is_convertible<
520 typename remove_pointer<_Up>::type(*)[],
521 element_type(*)[]>
522 >
523 >
524 >;
525
526 // Constructors.
527
528 /// Default constructor, creates a unique_ptr that owns nothing.
529 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
530 constexpr unique_ptr() noexcept
531 : _M_t()
532 { }
533
534 /** Takes ownership of a pointer.
535 *
536 * @param __p A pointer to an array of a type safely convertible
537 * to an array of @c element_type
538 *
539 * The deleter will be value-initialized.
540 */
541 template<typename _Up,
542 typename _Vp = _Dp,
543 typename = _DeleterConstraint<_Vp>,
544 typename = typename enable_if<
545 __safe_conversion_raw<_Up>::value, bool>::type>
546 explicit
547 unique_ptr(_Up __p) noexcept
548 : _M_t(__p)
549 { }
550
551 /** Takes ownership of a pointer.
552 *
553 * @param __p A pointer to an array of a type safely convertible
554 * to an array of @c element_type
555 * @param __d A reference to a deleter.
556 *
557 * The deleter will be initialized with @p __d
558 */
559 template<typename _Up, typename _Del = deleter_type,
560 typename = _Require<__safe_conversion_raw<_Up>,
561 is_copy_constructible<_Del>>>
562 unique_ptr(_Up __p, const deleter_type& __d) noexcept
563 : _M_t(__p, __d) { }
564
565 /** Takes ownership of a pointer.
566 *
567 * @param __p A pointer to an array of a type safely convertible
568 * to an array of @c element_type
569 * @param __d A reference to a deleter.
570 *
571 * The deleter will be initialized with @p std::move(__d)
572 */
573 template<typename _Up, typename _Del = deleter_type,
574 typename = _Require<__safe_conversion_raw<_Up>,
575 is_move_constructible<_Del>>>
576 unique_ptr(_Up __p,
577 __enable_if_t<!is_lvalue_reference<_Del>::value,
578 _Del&&> __d) noexcept
579 : _M_t(std::move(__p), std::move(__d))
580 { }
581
582 template<typename _Up, typename _Del = deleter_type,
583 typename _DelUnref = typename remove_reference<_Del>::type,
584 typename = _Require<__safe_conversion_raw<_Up>>>
585 unique_ptr(_Up,
586 __enable_if_t<is_lvalue_reference<_Del>::value,
587 _DelUnref&&>) = delete;
588
589 /// Move constructor.
590 unique_ptr(unique_ptr&&) = default;
591
592 /// Creates a unique_ptr that owns nothing.
593 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
594 constexpr unique_ptr(nullptr_t) noexcept
595 : _M_t()
596 { }
597
598 template<typename _Up, typename _Ep, typename = _Require<
599 __safe_conversion_up<_Up, _Ep>,
600 typename conditional<is_reference<_Dp>::value,
601 is_same<_Ep, _Dp>,
602 is_convertible<_Ep, _Dp>>::type>>
603 unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
604 : _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
605 { }
606
607 /// Destructor, invokes the deleter if the stored pointer is not null.
608 ~unique_ptr()
609 {
610 auto& __ptr = _M_t._M_ptr();
611 if (__ptr != nullptr)
612 get_deleter()(__ptr);
613 __ptr = pointer();
614 }
615
616 // Assignment.
617
618 /** @brief Move assignment operator.
619 *
620 * Invokes the deleter if this object owns a pointer.
621 */
622 unique_ptr&
623 operator=(unique_ptr&&) = default;
624
625 /** @brief Assignment from another type.
626 *
627 * @param __u The object to transfer ownership from, which owns a
628 * convertible pointer to an array object.
629 *
630 * Invokes the deleter if this object owns a pointer.
631 */
632 template<typename _Up, typename _Ep>
633 typename
634 enable_if<__and_<__safe_conversion_up<_Up, _Ep>,
635 is_assignable<deleter_type&, _Ep&&>
636 >::value,
637 unique_ptr&>::type
638 operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
639 {
640 reset(__u.release());
641 get_deleter() = std::forward<_Ep>(__u.get_deleter());
642 return *this;
643 }
644
645 /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
646 unique_ptr&
647 operator=(nullptr_t) noexcept
648 {
649 reset();
650 return *this;
651 }
652
653 // Observers.
654
655 /// Access an element of owned array.
656 typename std::add_lvalue_reference<element_type>::type
657 operator[](size_t __i) const
658 {
659 __glibcxx_assert(get() != pointer());
660 return get()[__i];
661 }
662
663 /// Return the stored pointer.
664 pointer
665 get() const noexcept
666 { return _M_t._M_ptr(); }
667
668 /// Return a reference to the stored deleter.
669 deleter_type&
670 get_deleter() noexcept
671 { return _M_t._M_deleter(); }
672
673 /// Return a reference to the stored deleter.
674 const deleter_type&
675 get_deleter() const noexcept
676 { return _M_t._M_deleter(); }
677
678 /// Return @c true if the stored pointer is not null.
679 explicit operator bool() const noexcept
680 { return get() == pointer() ? false : true; }
681
682 // Modifiers.
683
684 /// Release ownership of any stored pointer.
685 pointer
686 release() noexcept
687 { return _M_t.release(); }
688
689 /** @brief Replace the stored pointer.
690 *
691 * @param __p The new pointer to store.
692 *
693 * The deleter will be invoked if a pointer is already owned.
694 */
695 template <typename _Up,
696 typename = _Require<
697 __or_<is_same<_Up, pointer>,
698 __and_<is_same<pointer, element_type*>,
699 is_pointer<_Up>,
700 is_convertible<
701 typename remove_pointer<_Up>::type(*)[],
702 element_type(*)[]
703 >
704 >
705 >
706 >>
707 void
708 reset(_Up __p) noexcept
709 { _M_t.reset(std::move(__p)); }
710
711 void reset(nullptr_t = nullptr) noexcept
712 { reset(pointer()); }
713
714 /// Exchange the pointer and deleter with another object.
715 void
716 swap(unique_ptr& __u) noexcept
717 {
718 static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
719 _M_t.swap(__u._M_t);
720 }
721
722 // Disable copy from lvalue.
723 unique_ptr(const unique_ptr&) = delete;
724 unique_ptr& operator=(const unique_ptr&) = delete;
725 };
726
727 /// @relates unique_ptr @{
728
729 /// Swap overload for unique_ptr
730 template<typename _Tp, typename _Dp>
731 inline
732#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
733 // Constrained free swap overload, see p0185r1
734 typename enable_if<__is_swappable<_Dp>::value>::type
735#else
736 void
737#endif
738 swap(unique_ptr<_Tp, _Dp>& __x,
739 unique_ptr<_Tp, _Dp>& __y) noexcept
740 { __x.swap(__y); }
741
742#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
743 template<typename _Tp, typename _Dp>
744 typename enable_if<!__is_swappable<_Dp>::value>::type
745 swap(unique_ptr<_Tp, _Dp>&,
746 unique_ptr<_Tp, _Dp>&) = delete;
747#endif
748
749 /// Equality operator for unique_ptr objects, compares the owned pointers
750 template<typename _Tp, typename _Dp,
751 typename _Up, typename _Ep>
752 _GLIBCXX_NODISCARD inline bool
753 operator==(const unique_ptr<_Tp, _Dp>& __x,
754 const unique_ptr<_Up, _Ep>& __y)
755 { return __x.get() == __y.get(); }
756
757 /// unique_ptr comparison with nullptr
758 template<typename _Tp, typename _Dp>
759 _GLIBCXX_NODISCARD inline bool
760 operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
761 { return !__x; }
762
763#ifndef __cpp_lib_three_way_comparison
764 /// unique_ptr comparison with nullptr
765 template<typename _Tp, typename _Dp>
766 _GLIBCXX_NODISCARD inline bool
767 operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
768 { return !__x; }
769
770 /// Inequality operator for unique_ptr objects, compares the owned pointers
771 template<typename _Tp, typename _Dp,
772 typename _Up, typename _Ep>
773 _GLIBCXX_NODISCARD inline bool
774 operator!=(const unique_ptr<_Tp, _Dp>& __x,
775 const unique_ptr<_Up, _Ep>& __y)
776 { return __x.get() != __y.get(); }
777
778 /// unique_ptr comparison with nullptr
779 template<typename _Tp, typename _Dp>
780 _GLIBCXX_NODISCARD inline bool
781 operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
782 { return (bool)__x; }
783
784 /// unique_ptr comparison with nullptr
785 template<typename _Tp, typename _Dp>
786 _GLIBCXX_NODISCARD inline bool
787 operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
788 { return (bool)__x; }
789#endif // three way comparison
790
791 /// Relational operator for unique_ptr objects, compares the owned pointers
792 template<typename _Tp, typename _Dp,
793 typename _Up, typename _Ep>
794 _GLIBCXX_NODISCARD inline bool
795 operator<(const unique_ptr<_Tp, _Dp>& __x,
796 const unique_ptr<_Up, _Ep>& __y)
797 {
798 typedef typename
799 std::common_type<typename unique_ptr<_Tp, _Dp>::pointer,
800 typename unique_ptr<_Up, _Ep>::pointer>::type _CT;
801 return std::less<_CT>()(__x.get(), __y.get());
802 }
803
804 /// unique_ptr comparison with nullptr
805 template<typename _Tp, typename _Dp>
806 _GLIBCXX_NODISCARD inline bool
807 operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
808 {
809 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
810 nullptr);
811 }
812
813 /// unique_ptr comparison with nullptr
814 template<typename _Tp, typename _Dp>
815 _GLIBCXX_NODISCARD inline bool
816 operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
817 {
818 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
819 __x.get());
820 }
821
822 /// Relational operator for unique_ptr objects, compares the owned pointers
823 template<typename _Tp, typename _Dp,
824 typename _Up, typename _Ep>
825 _GLIBCXX_NODISCARD inline bool
826 operator<=(const unique_ptr<_Tp, _Dp>& __x,
827 const unique_ptr<_Up, _Ep>& __y)
828 { return !(__y < __x); }
829
830 /// unique_ptr comparison with nullptr
831 template<typename _Tp, typename _Dp>
832 _GLIBCXX_NODISCARD inline bool
833 operator<=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
834 { return !(nullptr < __x); }
835
836 /// unique_ptr comparison with nullptr
837 template<typename _Tp, typename _Dp>
838 _GLIBCXX_NODISCARD inline bool
839 operator<=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
840 { return !(__x < nullptr); }
841
842 /// Relational operator for unique_ptr objects, compares the owned pointers
843 template<typename _Tp, typename _Dp,
844 typename _Up, typename _Ep>
845 _GLIBCXX_NODISCARD inline bool
846 operator>(const unique_ptr<_Tp, _Dp>& __x,
847 const unique_ptr<_Up, _Ep>& __y)
848 { return (__y < __x); }
849
850 /// unique_ptr comparison with nullptr
851 template<typename _Tp, typename _Dp>
852 _GLIBCXX_NODISCARD inline bool
853 operator>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
854 {
855 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
856 __x.get());
857 }
858
859 /// unique_ptr comparison with nullptr
860 template<typename _Tp, typename _Dp>
861 _GLIBCXX_NODISCARD inline bool
862 operator>(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
863 {
864 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
865 nullptr);
866 }
867
868 /// Relational operator for unique_ptr objects, compares the owned pointers
869 template<typename _Tp, typename _Dp,
870 typename _Up, typename _Ep>
871 _GLIBCXX_NODISCARD inline bool
872 operator>=(const unique_ptr<_Tp, _Dp>& __x,
873 const unique_ptr<_Up, _Ep>& __y)
874 { return !(__x < __y); }
875
876 /// unique_ptr comparison with nullptr
877 template<typename _Tp, typename _Dp>
878 _GLIBCXX_NODISCARD inline bool
879 operator>=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
880 { return !(__x < nullptr); }
881
882 /// unique_ptr comparison with nullptr
883 template<typename _Tp, typename _Dp>
884 _GLIBCXX_NODISCARD inline bool
885 operator>=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
886 { return !(nullptr < __x); }
887
888#ifdef __cpp_lib_three_way_comparison
889 template<typename _Tp, typename _Dp, typename _Up, typename _Ep>
890 requires three_way_comparable_with<typename unique_ptr<_Tp, _Dp>::pointer,
891 typename unique_ptr<_Up, _Ep>::pointer>
892 inline
893 compare_three_way_result_t<typename unique_ptr<_Tp, _Dp>::pointer,
894 typename unique_ptr<_Up, _Ep>::pointer>
895 operator<=>(const unique_ptr<_Tp, _Dp>& __x,
896 const unique_ptr<_Up, _Ep>& __y)
897 { return compare_three_way()(__x.get(), __y.get()); }
898
899 template<typename _Tp, typename _Dp>
900 requires three_way_comparable<typename unique_ptr<_Tp, _Dp>::pointer>
901 inline
902 compare_three_way_result_t<typename unique_ptr<_Tp, _Dp>::pointer>
903 operator<=>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
904 {
905 using pointer = typename unique_ptr<_Tp, _Dp>::pointer;
906 return compare_three_way()(__x.get(), static_cast<pointer>(nullptr));
907 }
908#endif
909 /// @} relates unique_ptr
910
911 /// @cond undocumented
912 template<typename _Up, typename _Ptr = typename _Up::pointer,
913 bool = __poison_hash<_Ptr>::__enable_hash_call>
914 struct __uniq_ptr_hash
915#if ! _GLIBCXX_INLINE_VERSION
916 : private __poison_hash<_Ptr>
917#endif
918 {
919 size_t
920 operator()(const _Up& __u) const
921 noexcept(noexcept(std::declval<hash<_Ptr>>()(std::declval<_Ptr>())))
922 { return hash<_Ptr>()(__u.get()); }
923 };
924
925 template<typename _Up, typename _Ptr>
926 struct __uniq_ptr_hash<_Up, _Ptr, false>
927 : private __poison_hash<_Ptr>
928 { };
929 /// @endcond
930
931 /// std::hash specialization for unique_ptr.
932 template<typename _Tp, typename _Dp>
933 struct hash<unique_ptr<_Tp, _Dp>>
934 : public __hash_base<size_t, unique_ptr<_Tp, _Dp>>,
935 public __uniq_ptr_hash<unique_ptr<_Tp, _Dp>>
936 { };
937
938#if __cplusplus >= 201402L
939 /// @relates unique_ptr @{
940#define __cpp_lib_make_unique 201304
941
942 /// @cond undocumented
943
944 template<typename _Tp>
945 struct _MakeUniq
946 { typedef unique_ptr<_Tp> __single_object; };
947
948 template<typename _Tp>
949 struct _MakeUniq<_Tp[]>
950 { typedef unique_ptr<_Tp[]> __array; };
951
952 template<typename _Tp, size_t _Bound>
953 struct _MakeUniq<_Tp[_Bound]>
954 { struct __invalid_type { }; };
955
956 /// @endcond
957
958 /// std::make_unique for single objects
959 template<typename _Tp, typename... _Args>
960 inline typename _MakeUniq<_Tp>::__single_object
961 make_unique(_Args&&... __args)
962 { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
963
964 /// std::make_unique for arrays of unknown bound
965 template<typename _Tp>
966 inline typename _MakeUniq<_Tp>::__array
967 make_unique(size_t __num)
968 { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]()); }
969
970 /// Disable std::make_unique for arrays of known bound
971 template<typename _Tp, typename... _Args>
972 typename _MakeUniq<_Tp>::__invalid_type
973 make_unique(_Args&&...) = delete;
974
975#if __cplusplus > 201703L
976 /// std::make_unique_for_overwrite for single objects
977 template<typename _Tp>
978 inline typename _MakeUniq<_Tp>::__single_object
979 make_unique_for_overwrite()
980 { return unique_ptr<_Tp>(new _Tp); }
981
982 /// std::make_unique_for_overwrite for arrays of unknown bound
983 template<typename _Tp>
984 inline typename _MakeUniq<_Tp>::__array
985 make_unique_for_overwrite(size_t __n)
986 { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__n]); }
987
988 /// Disable std::make_unique_for_overwrite for arrays of known bound
989 template<typename _Tp, typename... _Args>
990 typename _MakeUniq<_Tp>::__invalid_type
991 make_unique_for_overwrite(_Args&&...) = delete;
992#endif // C++20
993
994 /// @} relates unique_ptr
995#endif // C++14
996
997#if __cplusplus > 201703L && __cpp_concepts
998 // _GLIBCXX_RESOLVE_LIB_DEFECTS
999 // 2948. unique_ptr does not define operator<< for stream output
1000 /// Stream output operator for unique_ptr
1001 template<typename _CharT, typename _Traits, typename _Tp, typename _Dp>
1002 inline basic_ostream<_CharT, _Traits>&
1003 operator<<(basic_ostream<_CharT, _Traits>& __os,
1004 const unique_ptr<_Tp, _Dp>& __p)
1005 requires requires { __os << __p.get(); }
1006 {
1007 __os << __p.get();
1008 return __os;
1009 }
1010#endif // C++20
1011
1012 /// @} group pointer_abstractions
1013
1014#if __cplusplus >= 201703L
1015 namespace __detail::__variant
1016 {
1017 template<typename> struct _Never_valueless_alt; // see <variant>
1018
1019 // Provide the strong exception-safety guarantee when emplacing a
1020 // unique_ptr into a variant.
1021 template<typename _Tp, typename _Del>
1022 struct _Never_valueless_alt<std::unique_ptr<_Tp, _Del>>
1023 : std::true_type
1024 { };
1025 } // namespace __detail::__variant
1026#endif // C++17
1027
1028_GLIBCXX_END_NAMESPACE_VERSION
1029} // namespace
1030
1031#endif /* _UNIQUE_PTR_H */
1032