xref: /llvm-project-15.0.7/libcxx/include/future (revision 6adbc83e)
1// -*- C++ -*-
2//===--------------------------- future -----------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_FUTURE
11#define _LIBCPP_FUTURE
12
13/*
14    future synopsis
15
16namespace std
17{
18
19enum class future_errc
20{
21    future_already_retrieved = 1,
22    promise_already_satisfied,
23    no_state,
24    broken_promise
25};
26
27enum class launch
28{
29    async = 1,
30    deferred = 2,
31    any = async | deferred
32};
33
34enum class future_status
35{
36    ready,
37    timeout,
38    deferred
39};
40
41template <> struct is_error_code_enum<future_errc> : public true_type { };
42error_code make_error_code(future_errc e) noexcept;
43error_condition make_error_condition(future_errc e) noexcept;
44
45const error_category& future_category() noexcept;
46
47class future_error
48    : public logic_error
49{
50public:
51    future_error(error_code ec);  // exposition only
52    explicit future_error(future_errc); // C++17
53    const error_code& code() const noexcept;
54    const char*       what() const noexcept;
55};
56
57template <class R>
58class promise
59{
60public:
61    promise();
62    template <class Allocator>
63        promise(allocator_arg_t, const Allocator& a);
64    promise(promise&& rhs) noexcept;
65    promise(const promise& rhs) = delete;
66    ~promise();
67
68    // assignment
69    promise& operator=(promise&& rhs) noexcept;
70    promise& operator=(const promise& rhs) = delete;
71    void swap(promise& other) noexcept;
72
73    // retrieving the result
74    future<R> get_future();
75
76    // setting the result
77    void set_value(const R& r);
78    void set_value(R&& r);
79    void set_exception(exception_ptr p);
80
81    // setting the result with deferred notification
82    void set_value_at_thread_exit(const R& r);
83    void set_value_at_thread_exit(R&& r);
84    void set_exception_at_thread_exit(exception_ptr p);
85};
86
87template <class R>
88class promise<R&>
89{
90public:
91    promise();
92    template <class Allocator>
93        promise(allocator_arg_t, const Allocator& a);
94    promise(promise&& rhs) noexcept;
95    promise(const promise& rhs) = delete;
96    ~promise();
97
98    // assignment
99    promise& operator=(promise&& rhs) noexcept;
100    promise& operator=(const promise& rhs) = delete;
101    void swap(promise& other) noexcept;
102
103    // retrieving the result
104    future<R&> get_future();
105
106    // setting the result
107    void set_value(R& r);
108    void set_exception(exception_ptr p);
109
110    // setting the result with deferred notification
111    void set_value_at_thread_exit(R&);
112    void set_exception_at_thread_exit(exception_ptr p);
113};
114
115template <>
116class promise<void>
117{
118public:
119    promise();
120    template <class Allocator>
121        promise(allocator_arg_t, const Allocator& a);
122    promise(promise&& rhs) noexcept;
123    promise(const promise& rhs) = delete;
124    ~promise();
125
126    // assignment
127    promise& operator=(promise&& rhs) noexcept;
128    promise& operator=(const promise& rhs) = delete;
129    void swap(promise& other) noexcept;
130
131    // retrieving the result
132    future<void> get_future();
133
134    // setting the result
135    void set_value();
136    void set_exception(exception_ptr p);
137
138    // setting the result with deferred notification
139    void set_value_at_thread_exit();
140    void set_exception_at_thread_exit(exception_ptr p);
141};
142
143template <class R> void swap(promise<R>& x, promise<R>& y) noexcept;
144
145template <class R, class Alloc>
146    struct uses_allocator<promise<R>, Alloc> : public true_type {};
147
148template <class R>
149class future
150{
151public:
152    future() noexcept;
153    future(future&&) noexcept;
154    future(const future& rhs) = delete;
155    ~future();
156    future& operator=(const future& rhs) = delete;
157    future& operator=(future&&) noexcept;
158    shared_future<R> share() noexcept;
159
160    // retrieving the value
161    R get();
162
163    // functions to check state
164    bool valid() const noexcept;
165
166    void wait() const;
167    template <class Rep, class Period>
168        future_status
169        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
170    template <class Clock, class Duration>
171        future_status
172        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
173};
174
175template <class R>
176class future<R&>
177{
178public:
179    future() noexcept;
180    future(future&&) noexcept;
181    future(const future& rhs) = delete;
182    ~future();
183    future& operator=(const future& rhs) = delete;
184    future& operator=(future&&) noexcept;
185    shared_future<R&> share() noexcept;
186
187    // retrieving the value
188    R& get();
189
190    // functions to check state
191    bool valid() const noexcept;
192
193    void wait() const;
194    template <class Rep, class Period>
195        future_status
196        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
197    template <class Clock, class Duration>
198        future_status
199        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
200};
201
202template <>
203class future<void>
204{
205public:
206    future() noexcept;
207    future(future&&) noexcept;
208    future(const future& rhs) = delete;
209    ~future();
210    future& operator=(const future& rhs) = delete;
211    future& operator=(future&&) noexcept;
212    shared_future<void> share() noexcept;
213
214    // retrieving the value
215    void get();
216
217    // functions to check state
218    bool valid() const noexcept;
219
220    void wait() const;
221    template <class Rep, class Period>
222        future_status
223        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
224    template <class Clock, class Duration>
225        future_status
226        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
227};
228
229template <class R>
230class shared_future
231{
232public:
233    shared_future() noexcept;
234    shared_future(const shared_future& rhs);
235    shared_future(future<R>&&) noexcept;
236    shared_future(shared_future&& rhs) noexcept;
237    ~shared_future();
238    shared_future& operator=(const shared_future& rhs);
239    shared_future& operator=(shared_future&& rhs) noexcept;
240
241    // retrieving the value
242    const R& get() const;
243
244    // functions to check state
245    bool valid() const noexcept;
246
247    void wait() const;
248    template <class Rep, class Period>
249        future_status
250        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
251    template <class Clock, class Duration>
252        future_status
253        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
254};
255
256template <class R>
257class shared_future<R&>
258{
259public:
260    shared_future() noexcept;
261    shared_future(const shared_future& rhs);
262    shared_future(future<R&>&&) noexcept;
263    shared_future(shared_future&& rhs) noexcept;
264    ~shared_future();
265    shared_future& operator=(const shared_future& rhs);
266    shared_future& operator=(shared_future&& rhs) noexcept;
267
268    // retrieving the value
269    R& get() const;
270
271    // functions to check state
272    bool valid() const noexcept;
273
274    void wait() const;
275    template <class Rep, class Period>
276        future_status
277        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
278    template <class Clock, class Duration>
279        future_status
280        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
281};
282
283template <>
284class shared_future<void>
285{
286public:
287    shared_future() noexcept;
288    shared_future(const shared_future& rhs);
289    shared_future(future<void>&&) noexcept;
290    shared_future(shared_future&& rhs) noexcept;
291    ~shared_future();
292    shared_future& operator=(const shared_future& rhs);
293    shared_future& operator=(shared_future&& rhs) noexcept;
294
295    // retrieving the value
296    void get() const;
297
298    // functions to check state
299    bool valid() const noexcept;
300
301    void wait() const;
302    template <class Rep, class Period>
303        future_status
304        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
305    template <class Clock, class Duration>
306        future_status
307        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
308};
309
310template <class F, class... Args>
311  future<typename result_of<typename decay<F>::type(typename decay<Args>::type...)>::type>
312  async(F&& f, Args&&... args);
313
314template <class F, class... Args>
315  future<typename result_of<typename decay<F>::type(typename decay<Args>::type...)>::type>
316  async(launch policy, F&& f, Args&&... args);
317
318template <class> class packaged_task; // undefined
319
320template <class R, class... ArgTypes>
321class packaged_task<R(ArgTypes...)>
322{
323public:
324    typedef R result_type; // extension
325
326    // construction and destruction
327    packaged_task() noexcept;
328    template <class F>
329        explicit packaged_task(F&& f);
330    template <class F, class Allocator>
331        packaged_task(allocator_arg_t, const Allocator& a, F&& f);
332    ~packaged_task();
333
334    // no copy
335    packaged_task(const packaged_task&) = delete;
336    packaged_task& operator=(const packaged_task&) = delete;
337
338    // move support
339    packaged_task(packaged_task&& other) noexcept;
340    packaged_task& operator=(packaged_task&& other) noexcept;
341    void swap(packaged_task& other) noexcept;
342
343    bool valid() const noexcept;
344
345    // result retrieval
346    future<R> get_future();
347
348    // execution
349    void operator()(ArgTypes... );
350    void make_ready_at_thread_exit(ArgTypes...);
351
352    void reset();
353};
354
355template <class R>
356  void swap(packaged_task<R(ArgTypes...)&, packaged_task<R(ArgTypes...)>&) noexcept;
357
358template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
359
360}  // std
361
362*/
363
364#include <__availability>
365#include <__config>
366#include <__debug>
367#include <__utility/__decay_copy.h>
368#include <__utility/forward.h>
369#include <chrono>
370#include <exception>
371#include <memory>
372#include <mutex>
373#include <system_error>
374#include <thread>
375
376#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
377#pragma GCC system_header
378#endif
379
380#ifdef _LIBCPP_HAS_NO_THREADS
381#error <future> is not supported on this single threaded system
382#else // !_LIBCPP_HAS_NO_THREADS
383
384_LIBCPP_BEGIN_NAMESPACE_STD
385
386//enum class future_errc
387_LIBCPP_DECLARE_STRONG_ENUM(future_errc)
388{
389    future_already_retrieved = 1,
390    promise_already_satisfied,
391    no_state,
392    broken_promise
393};
394_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_errc)
395
396template <>
397struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc> : public true_type {};
398
399#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
400template <>
401struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc::__lx> : public true_type { };
402#endif
403
404//enum class launch
405_LIBCPP_DECLARE_STRONG_ENUM(launch)
406{
407    async = 1,
408    deferred = 2,
409    any = async | deferred
410};
411_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(launch)
412
413#ifndef _LIBCPP_HAS_NO_STRONG_ENUMS
414
415typedef underlying_type<launch>::type __launch_underlying_type;
416
417inline _LIBCPP_INLINE_VISIBILITY
418_LIBCPP_CONSTEXPR
419launch
420operator&(launch __x, launch __y)
421{
422    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) &
423                               static_cast<__launch_underlying_type>(__y));
424}
425
426inline _LIBCPP_INLINE_VISIBILITY
427_LIBCPP_CONSTEXPR
428launch
429operator|(launch __x, launch __y)
430{
431    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) |
432                               static_cast<__launch_underlying_type>(__y));
433}
434
435inline _LIBCPP_INLINE_VISIBILITY
436_LIBCPP_CONSTEXPR
437launch
438operator^(launch __x, launch __y)
439{
440    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) ^
441                               static_cast<__launch_underlying_type>(__y));
442}
443
444inline _LIBCPP_INLINE_VISIBILITY
445_LIBCPP_CONSTEXPR
446launch
447operator~(launch __x)
448{
449    return static_cast<launch>(~static_cast<__launch_underlying_type>(__x) & 3);
450}
451
452inline _LIBCPP_INLINE_VISIBILITY
453launch&
454operator&=(launch& __x, launch __y)
455{
456    __x = __x & __y; return __x;
457}
458
459inline _LIBCPP_INLINE_VISIBILITY
460launch&
461operator|=(launch& __x, launch __y)
462{
463    __x = __x | __y; return __x;
464}
465
466inline _LIBCPP_INLINE_VISIBILITY
467launch&
468operator^=(launch& __x, launch __y)
469{
470    __x = __x ^ __y; return __x;
471}
472
473#endif // !_LIBCPP_HAS_NO_STRONG_ENUMS
474
475//enum class future_status
476_LIBCPP_DECLARE_STRONG_ENUM(future_status)
477{
478    ready,
479    timeout,
480    deferred
481};
482_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_status)
483
484_LIBCPP_FUNC_VIS
485const error_category& future_category() _NOEXCEPT;
486
487inline _LIBCPP_INLINE_VISIBILITY
488error_code
489make_error_code(future_errc __e) _NOEXCEPT
490{
491    return error_code(static_cast<int>(__e), future_category());
492}
493
494inline _LIBCPP_INLINE_VISIBILITY
495error_condition
496make_error_condition(future_errc __e) _NOEXCEPT
497{
498    return error_condition(static_cast<int>(__e), future_category());
499}
500
501class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_FUTURE_ERROR future_error
502    : public logic_error
503{
504    error_code __ec_;
505public:
506    future_error(error_code __ec);
507
508    _LIBCPP_INLINE_VISIBILITY
509    const error_code& code() const _NOEXCEPT {return __ec_;}
510
511    future_error(const future_error&) _NOEXCEPT = default;
512    virtual ~future_error() _NOEXCEPT;
513};
514
515_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
516#ifndef _LIBCPP_NO_EXCEPTIONS
517_LIBCPP_AVAILABILITY_FUTURE_ERROR
518#endif
519void __throw_future_error(future_errc _Ev)
520{
521#ifndef _LIBCPP_NO_EXCEPTIONS
522    throw future_error(make_error_code(_Ev));
523#else
524    ((void)_Ev);
525    _VSTD::abort();
526#endif
527}
528
529class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE __assoc_sub_state
530    : public __shared_count
531{
532protected:
533    exception_ptr __exception_;
534    mutable mutex __mut_;
535    mutable condition_variable __cv_;
536    unsigned __state_;
537
538    virtual void __on_zero_shared() _NOEXCEPT;
539    void __sub_wait(unique_lock<mutex>& __lk);
540public:
541    enum
542    {
543        __constructed = 1,
544        __future_attached = 2,
545        ready = 4,
546        deferred = 8
547    };
548
549    _LIBCPP_INLINE_VISIBILITY
550    __assoc_sub_state() : __state_(0) {}
551
552    _LIBCPP_INLINE_VISIBILITY
553    bool __has_value() const
554        {return (__state_ & __constructed) || (__exception_ != nullptr);}
555
556    _LIBCPP_INLINE_VISIBILITY
557    void __attach_future() {
558        lock_guard<mutex> __lk(__mut_);
559        bool __has_future_attached = (__state_ & __future_attached) != 0;
560        if (__has_future_attached)
561            __throw_future_error(future_errc::future_already_retrieved);
562        this->__add_shared();
563        __state_ |= __future_attached;
564    }
565
566    _LIBCPP_INLINE_VISIBILITY
567    void __set_deferred() {__state_ |= deferred;}
568
569    void __make_ready();
570    _LIBCPP_INLINE_VISIBILITY
571    bool __is_ready() const {return (__state_ & ready) != 0;}
572
573    void set_value();
574    void set_value_at_thread_exit();
575
576    void set_exception(exception_ptr __p);
577    void set_exception_at_thread_exit(exception_ptr __p);
578
579    void copy();
580
581    void wait();
582    template <class _Rep, class _Period>
583        future_status
584        _LIBCPP_INLINE_VISIBILITY
585        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const;
586    template <class _Clock, class _Duration>
587        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
588        future_status
589        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const;
590
591    virtual void __execute();
592};
593
594template <class _Clock, class _Duration>
595future_status
596__assoc_sub_state::wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
597{
598    unique_lock<mutex> __lk(__mut_);
599    if (__state_ & deferred)
600        return future_status::deferred;
601    while (!(__state_ & ready) && _Clock::now() < __abs_time)
602        __cv_.wait_until(__lk, __abs_time);
603    if (__state_ & ready)
604        return future_status::ready;
605    return future_status::timeout;
606}
607
608template <class _Rep, class _Period>
609inline
610future_status
611__assoc_sub_state::wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
612{
613    return wait_until(chrono::steady_clock::now() + __rel_time);
614}
615
616template <class _Rp>
617class _LIBCPP_AVAILABILITY_FUTURE _LIBCPP_HIDDEN __assoc_state
618    : public __assoc_sub_state
619{
620    typedef __assoc_sub_state base;
621    typedef typename aligned_storage<sizeof(_Rp), alignment_of<_Rp>::value>::type _Up;
622protected:
623    _Up __value_;
624
625    virtual void __on_zero_shared() _NOEXCEPT;
626public:
627
628    template <class _Arg>
629    void set_value(_Arg&& __arg);
630
631    template <class _Arg>
632    void set_value_at_thread_exit(_Arg&& __arg);
633
634    _Rp move();
635    typename add_lvalue_reference<_Rp>::type copy();
636};
637
638template <class _Rp>
639void
640__assoc_state<_Rp>::__on_zero_shared() _NOEXCEPT
641{
642    if (this->__state_ & base::__constructed)
643        reinterpret_cast<_Rp*>(&__value_)->~_Rp();
644    delete this;
645}
646
647template <class _Rp>
648template <class _Arg>
649_LIBCPP_AVAILABILITY_FUTURE
650void
651__assoc_state<_Rp>::set_value(_Arg&& __arg)
652{
653    unique_lock<mutex> __lk(this->__mut_);
654    if (this->__has_value())
655        __throw_future_error(future_errc::promise_already_satisfied);
656    ::new ((void*)&__value_) _Rp(_VSTD::forward<_Arg>(__arg));
657    this->__state_ |= base::__constructed | base::ready;
658    __cv_.notify_all();
659}
660
661template <class _Rp>
662template <class _Arg>
663void
664__assoc_state<_Rp>::set_value_at_thread_exit(_Arg&& __arg)
665{
666    unique_lock<mutex> __lk(this->__mut_);
667    if (this->__has_value())
668        __throw_future_error(future_errc::promise_already_satisfied);
669    ::new ((void*)&__value_) _Rp(_VSTD::forward<_Arg>(__arg));
670    this->__state_ |= base::__constructed;
671    __thread_local_data()->__make_ready_at_thread_exit(this);
672}
673
674template <class _Rp>
675_Rp
676__assoc_state<_Rp>::move()
677{
678    unique_lock<mutex> __lk(this->__mut_);
679    this->__sub_wait(__lk);
680    if (this->__exception_ != nullptr)
681        rethrow_exception(this->__exception_);
682    return _VSTD::move(*reinterpret_cast<_Rp*>(&__value_));
683}
684
685template <class _Rp>
686typename add_lvalue_reference<_Rp>::type
687__assoc_state<_Rp>::copy()
688{
689    unique_lock<mutex> __lk(this->__mut_);
690    this->__sub_wait(__lk);
691    if (this->__exception_ != nullptr)
692        rethrow_exception(this->__exception_);
693    return *reinterpret_cast<_Rp*>(&__value_);
694}
695
696template <class _Rp>
697class _LIBCPP_AVAILABILITY_FUTURE __assoc_state<_Rp&>
698    : public __assoc_sub_state
699{
700    typedef __assoc_sub_state base;
701    typedef _Rp* _Up;
702protected:
703    _Up __value_;
704
705    virtual void __on_zero_shared() _NOEXCEPT;
706public:
707
708    void set_value(_Rp& __arg);
709    void set_value_at_thread_exit(_Rp& __arg);
710
711    _Rp& copy();
712};
713
714template <class _Rp>
715void
716__assoc_state<_Rp&>::__on_zero_shared() _NOEXCEPT
717{
718    delete this;
719}
720
721template <class _Rp>
722void
723__assoc_state<_Rp&>::set_value(_Rp& __arg)
724{
725    unique_lock<mutex> __lk(this->__mut_);
726    if (this->__has_value())
727        __throw_future_error(future_errc::promise_already_satisfied);
728    __value_ = _VSTD::addressof(__arg);
729    this->__state_ |= base::__constructed | base::ready;
730    __cv_.notify_all();
731}
732
733template <class _Rp>
734void
735__assoc_state<_Rp&>::set_value_at_thread_exit(_Rp& __arg)
736{
737    unique_lock<mutex> __lk(this->__mut_);
738    if (this->__has_value())
739        __throw_future_error(future_errc::promise_already_satisfied);
740    __value_ = _VSTD::addressof(__arg);
741    this->__state_ |= base::__constructed;
742    __thread_local_data()->__make_ready_at_thread_exit(this);
743}
744
745template <class _Rp>
746_Rp&
747__assoc_state<_Rp&>::copy()
748{
749    unique_lock<mutex> __lk(this->__mut_);
750    this->__sub_wait(__lk);
751    if (this->__exception_ != nullptr)
752        rethrow_exception(this->__exception_);
753    return *__value_;
754}
755
756template <class _Rp, class _Alloc>
757class _LIBCPP_AVAILABILITY_FUTURE __assoc_state_alloc
758    : public __assoc_state<_Rp>
759{
760    typedef __assoc_state<_Rp> base;
761    _Alloc __alloc_;
762
763    virtual void __on_zero_shared() _NOEXCEPT;
764public:
765    _LIBCPP_INLINE_VISIBILITY
766    explicit __assoc_state_alloc(const _Alloc& __a)
767        : __alloc_(__a) {}
768};
769
770template <class _Rp, class _Alloc>
771void
772__assoc_state_alloc<_Rp, _Alloc>::__on_zero_shared() _NOEXCEPT
773{
774    if (this->__state_ & base::__constructed)
775        reinterpret_cast<_Rp*>(_VSTD::addressof(this->__value_))->~_Rp();
776    typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;
777    typedef allocator_traits<_Al> _ATraits;
778    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
779    _Al __a(__alloc_);
780    this->~__assoc_state_alloc();
781    __a.deallocate(_PTraits::pointer_to(*this), 1);
782}
783
784template <class _Rp, class _Alloc>
785class _LIBCPP_AVAILABILITY_FUTURE __assoc_state_alloc<_Rp&, _Alloc>
786    : public __assoc_state<_Rp&>
787{
788    typedef __assoc_state<_Rp&> base;
789    _Alloc __alloc_;
790
791    virtual void __on_zero_shared() _NOEXCEPT;
792public:
793    _LIBCPP_INLINE_VISIBILITY
794    explicit __assoc_state_alloc(const _Alloc& __a)
795        : __alloc_(__a) {}
796};
797
798template <class _Rp, class _Alloc>
799void
800__assoc_state_alloc<_Rp&, _Alloc>::__on_zero_shared() _NOEXCEPT
801{
802    typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;
803    typedef allocator_traits<_Al> _ATraits;
804    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
805    _Al __a(__alloc_);
806    this->~__assoc_state_alloc();
807    __a.deallocate(_PTraits::pointer_to(*this), 1);
808}
809
810template <class _Alloc>
811class _LIBCPP_AVAILABILITY_FUTURE __assoc_sub_state_alloc
812    : public __assoc_sub_state
813{
814    typedef __assoc_sub_state base;
815    _Alloc __alloc_;
816
817    virtual void __on_zero_shared() _NOEXCEPT;
818public:
819    _LIBCPP_INLINE_VISIBILITY
820    explicit __assoc_sub_state_alloc(const _Alloc& __a)
821        : __alloc_(__a) {}
822};
823
824template <class _Alloc>
825void
826__assoc_sub_state_alloc<_Alloc>::__on_zero_shared() _NOEXCEPT
827{
828    typedef typename __allocator_traits_rebind<_Alloc, __assoc_sub_state_alloc>::type _Al;
829    typedef allocator_traits<_Al> _ATraits;
830    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
831    _Al __a(__alloc_);
832    this->~__assoc_sub_state_alloc();
833    __a.deallocate(_PTraits::pointer_to(*this), 1);
834}
835
836template <class _Rp, class _Fp>
837class _LIBCPP_AVAILABILITY_FUTURE __deferred_assoc_state
838    : public __assoc_state<_Rp>
839{
840    typedef __assoc_state<_Rp> base;
841
842    _Fp __func_;
843
844public:
845    _LIBCPP_INLINE_VISIBILITY
846    explicit __deferred_assoc_state(_Fp&& __f);
847
848    virtual void __execute();
849};
850
851template <class _Rp, class _Fp>
852inline
853__deferred_assoc_state<_Rp, _Fp>::__deferred_assoc_state(_Fp&& __f)
854    : __func_(_VSTD::forward<_Fp>(__f))
855{
856    this->__set_deferred();
857}
858
859template <class _Rp, class _Fp>
860void
861__deferred_assoc_state<_Rp, _Fp>::__execute()
862{
863#ifndef _LIBCPP_NO_EXCEPTIONS
864    try
865    {
866#endif // _LIBCPP_NO_EXCEPTIONS
867        this->set_value(__func_());
868#ifndef _LIBCPP_NO_EXCEPTIONS
869    }
870    catch (...)
871    {
872        this->set_exception(current_exception());
873    }
874#endif // _LIBCPP_NO_EXCEPTIONS
875}
876
877template <class _Fp>
878class _LIBCPP_AVAILABILITY_FUTURE __deferred_assoc_state<void, _Fp>
879    : public __assoc_sub_state
880{
881    typedef __assoc_sub_state base;
882
883    _Fp __func_;
884
885public:
886    _LIBCPP_INLINE_VISIBILITY
887    explicit __deferred_assoc_state(_Fp&& __f);
888
889    virtual void __execute();
890};
891
892template <class _Fp>
893inline
894__deferred_assoc_state<void, _Fp>::__deferred_assoc_state(_Fp&& __f)
895    : __func_(_VSTD::forward<_Fp>(__f))
896{
897    this->__set_deferred();
898}
899
900template <class _Fp>
901void
902__deferred_assoc_state<void, _Fp>::__execute()
903{
904#ifndef _LIBCPP_NO_EXCEPTIONS
905    try
906    {
907#endif // _LIBCPP_NO_EXCEPTIONS
908        __func_();
909        this->set_value();
910#ifndef _LIBCPP_NO_EXCEPTIONS
911    }
912    catch (...)
913    {
914        this->set_exception(current_exception());
915    }
916#endif // _LIBCPP_NO_EXCEPTIONS
917}
918
919template <class _Rp, class _Fp>
920class _LIBCPP_AVAILABILITY_FUTURE __async_assoc_state
921    : public __assoc_state<_Rp>
922{
923    typedef __assoc_state<_Rp> base;
924
925    _Fp __func_;
926
927    virtual void __on_zero_shared() _NOEXCEPT;
928public:
929    _LIBCPP_INLINE_VISIBILITY
930    explicit __async_assoc_state(_Fp&& __f);
931
932    virtual void __execute();
933};
934
935template <class _Rp, class _Fp>
936inline
937__async_assoc_state<_Rp, _Fp>::__async_assoc_state(_Fp&& __f)
938    : __func_(_VSTD::forward<_Fp>(__f))
939{
940}
941
942template <class _Rp, class _Fp>
943void
944__async_assoc_state<_Rp, _Fp>::__execute()
945{
946#ifndef _LIBCPP_NO_EXCEPTIONS
947    try
948    {
949#endif // _LIBCPP_NO_EXCEPTIONS
950        this->set_value(__func_());
951#ifndef _LIBCPP_NO_EXCEPTIONS
952    }
953    catch (...)
954    {
955        this->set_exception(current_exception());
956    }
957#endif // _LIBCPP_NO_EXCEPTIONS
958}
959
960template <class _Rp, class _Fp>
961void
962__async_assoc_state<_Rp, _Fp>::__on_zero_shared() _NOEXCEPT
963{
964    this->wait();
965    base::__on_zero_shared();
966}
967
968template <class _Fp>
969class _LIBCPP_AVAILABILITY_FUTURE __async_assoc_state<void, _Fp>
970    : public __assoc_sub_state
971{
972    typedef __assoc_sub_state base;
973
974    _Fp __func_;
975
976    virtual void __on_zero_shared() _NOEXCEPT;
977public:
978    _LIBCPP_INLINE_VISIBILITY
979    explicit __async_assoc_state(_Fp&& __f);
980
981    virtual void __execute();
982};
983
984template <class _Fp>
985inline
986__async_assoc_state<void, _Fp>::__async_assoc_state(_Fp&& __f)
987    : __func_(_VSTD::forward<_Fp>(__f))
988{
989}
990
991template <class _Fp>
992void
993__async_assoc_state<void, _Fp>::__execute()
994{
995#ifndef _LIBCPP_NO_EXCEPTIONS
996    try
997    {
998#endif // _LIBCPP_NO_EXCEPTIONS
999        __func_();
1000        this->set_value();
1001#ifndef _LIBCPP_NO_EXCEPTIONS
1002    }
1003    catch (...)
1004    {
1005        this->set_exception(current_exception());
1006    }
1007#endif // _LIBCPP_NO_EXCEPTIONS
1008}
1009
1010template <class _Fp>
1011void
1012__async_assoc_state<void, _Fp>::__on_zero_shared() _NOEXCEPT
1013{
1014    this->wait();
1015    base::__on_zero_shared();
1016}
1017
1018template <class _Rp> class _LIBCPP_TEMPLATE_VIS promise;
1019template <class _Rp> class _LIBCPP_TEMPLATE_VIS shared_future;
1020
1021// future
1022
1023template <class _Rp> class _LIBCPP_TEMPLATE_VIS future;
1024
1025template <class _Rp, class _Fp>
1026_LIBCPP_INLINE_VISIBILITY future<_Rp>
1027__make_deferred_assoc_state(_Fp&& __f);
1028
1029template <class _Rp, class _Fp>
1030_LIBCPP_INLINE_VISIBILITY future<_Rp>
1031__make_async_assoc_state(_Fp&& __f);
1032
1033template <class _Rp>
1034class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE future
1035{
1036    __assoc_state<_Rp>* __state_;
1037
1038    explicit future(__assoc_state<_Rp>* __state);
1039
1040    template <class> friend class promise;
1041    template <class> friend class shared_future;
1042
1043    template <class _R1, class _Fp>
1044        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
1045    template <class _R1, class _Fp>
1046        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
1047
1048public:
1049    _LIBCPP_INLINE_VISIBILITY
1050    future() _NOEXCEPT : __state_(nullptr) {}
1051    _LIBCPP_INLINE_VISIBILITY
1052    future(future&& __rhs) _NOEXCEPT
1053        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1054    future(const future&) = delete;
1055    future& operator=(const future&) = delete;
1056    _LIBCPP_INLINE_VISIBILITY
1057    future& operator=(future&& __rhs) _NOEXCEPT
1058        {
1059            future(_VSTD::move(__rhs)).swap(*this);
1060            return *this;
1061        }
1062
1063    ~future();
1064    _LIBCPP_INLINE_VISIBILITY
1065    shared_future<_Rp> share() _NOEXCEPT;
1066
1067    // retrieving the value
1068    _Rp get();
1069
1070    _LIBCPP_INLINE_VISIBILITY
1071    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1072
1073    // functions to check state
1074    _LIBCPP_INLINE_VISIBILITY
1075    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
1076
1077    _LIBCPP_INLINE_VISIBILITY
1078    void wait() const {__state_->wait();}
1079    template <class _Rep, class _Period>
1080        _LIBCPP_INLINE_VISIBILITY
1081        future_status
1082        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
1083            {return __state_->wait_for(__rel_time);}
1084    template <class _Clock, class _Duration>
1085        _LIBCPP_INLINE_VISIBILITY
1086        future_status
1087        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
1088            {return __state_->wait_until(__abs_time);}
1089};
1090
1091template <class _Rp>
1092future<_Rp>::future(__assoc_state<_Rp>* __state)
1093    : __state_(__state)
1094{
1095    __state_->__attach_future();
1096}
1097
1098struct __release_shared_count
1099{
1100    void operator()(__shared_count* p) {p->__release_shared();}
1101};
1102
1103template <class _Rp>
1104future<_Rp>::~future()
1105{
1106    if (__state_)
1107        __state_->__release_shared();
1108}
1109
1110template <class _Rp>
1111_Rp
1112future<_Rp>::get()
1113{
1114    unique_ptr<__shared_count, __release_shared_count> __(__state_);
1115    __assoc_state<_Rp>* __s = __state_;
1116    __state_ = nullptr;
1117    return __s->move();
1118}
1119
1120template <class _Rp>
1121class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE future<_Rp&>
1122{
1123    __assoc_state<_Rp&>* __state_;
1124
1125    explicit future(__assoc_state<_Rp&>* __state);
1126
1127    template <class> friend class promise;
1128    template <class> friend class shared_future;
1129
1130    template <class _R1, class _Fp>
1131        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
1132    template <class _R1, class _Fp>
1133        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
1134
1135public:
1136    _LIBCPP_INLINE_VISIBILITY
1137    future() _NOEXCEPT : __state_(nullptr) {}
1138    _LIBCPP_INLINE_VISIBILITY
1139    future(future&& __rhs) _NOEXCEPT
1140        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1141    future(const future&) = delete;
1142    future& operator=(const future&) = delete;
1143    _LIBCPP_INLINE_VISIBILITY
1144    future& operator=(future&& __rhs) _NOEXCEPT
1145        {
1146            future(_VSTD::move(__rhs)).swap(*this);
1147            return *this;
1148        }
1149
1150    ~future();
1151    _LIBCPP_INLINE_VISIBILITY
1152    shared_future<_Rp&> share() _NOEXCEPT;
1153
1154    // retrieving the value
1155    _Rp& get();
1156
1157    _LIBCPP_INLINE_VISIBILITY
1158    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1159
1160    // functions to check state
1161    _LIBCPP_INLINE_VISIBILITY
1162    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
1163
1164    _LIBCPP_INLINE_VISIBILITY
1165    void wait() const {__state_->wait();}
1166    template <class _Rep, class _Period>
1167        _LIBCPP_INLINE_VISIBILITY
1168        future_status
1169        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
1170            {return __state_->wait_for(__rel_time);}
1171    template <class _Clock, class _Duration>
1172        _LIBCPP_INLINE_VISIBILITY
1173        future_status
1174        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
1175            {return __state_->wait_until(__abs_time);}
1176};
1177
1178template <class _Rp>
1179future<_Rp&>::future(__assoc_state<_Rp&>* __state)
1180    : __state_(__state)
1181{
1182    __state_->__attach_future();
1183}
1184
1185template <class _Rp>
1186future<_Rp&>::~future()
1187{
1188    if (__state_)
1189        __state_->__release_shared();
1190}
1191
1192template <class _Rp>
1193_Rp&
1194future<_Rp&>::get()
1195{
1196    unique_ptr<__shared_count, __release_shared_count> __(__state_);
1197    __assoc_state<_Rp&>* __s = __state_;
1198    __state_ = nullptr;
1199    return __s->copy();
1200}
1201
1202template <>
1203class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE future<void>
1204{
1205    __assoc_sub_state* __state_;
1206
1207    explicit future(__assoc_sub_state* __state);
1208
1209    template <class> friend class promise;
1210    template <class> friend class shared_future;
1211
1212    template <class _R1, class _Fp>
1213        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
1214    template <class _R1, class _Fp>
1215        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
1216
1217public:
1218    _LIBCPP_INLINE_VISIBILITY
1219    future() _NOEXCEPT : __state_(nullptr) {}
1220    _LIBCPP_INLINE_VISIBILITY
1221    future(future&& __rhs) _NOEXCEPT
1222        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1223    future(const future&) = delete;
1224    future& operator=(const future&) = delete;
1225    _LIBCPP_INLINE_VISIBILITY
1226    future& operator=(future&& __rhs) _NOEXCEPT
1227        {
1228            future(_VSTD::move(__rhs)).swap(*this);
1229            return *this;
1230        }
1231
1232    ~future();
1233    _LIBCPP_INLINE_VISIBILITY
1234    shared_future<void> share() _NOEXCEPT;
1235
1236    // retrieving the value
1237    void get();
1238
1239    _LIBCPP_INLINE_VISIBILITY
1240    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1241
1242    // functions to check state
1243    _LIBCPP_INLINE_VISIBILITY
1244    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
1245
1246    _LIBCPP_INLINE_VISIBILITY
1247    void wait() const {__state_->wait();}
1248    template <class _Rep, class _Period>
1249        _LIBCPP_INLINE_VISIBILITY
1250        future_status
1251        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
1252            {return __state_->wait_for(__rel_time);}
1253    template <class _Clock, class _Duration>
1254        _LIBCPP_INLINE_VISIBILITY
1255        future_status
1256        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
1257            {return __state_->wait_until(__abs_time);}
1258};
1259
1260template <class _Rp>
1261inline _LIBCPP_INLINE_VISIBILITY
1262void
1263swap(future<_Rp>& __x, future<_Rp>& __y) _NOEXCEPT
1264{
1265    __x.swap(__y);
1266}
1267
1268// promise<R>
1269
1270template <class _Callable> class packaged_task;
1271
1272template <class _Rp>
1273class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE promise
1274{
1275    __assoc_state<_Rp>* __state_;
1276
1277    _LIBCPP_INLINE_VISIBILITY
1278    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
1279
1280    template <class> friend class packaged_task;
1281public:
1282    promise();
1283    template <class _Alloc>
1284        promise(allocator_arg_t, const _Alloc& __a);
1285    _LIBCPP_INLINE_VISIBILITY
1286    promise(promise&& __rhs) _NOEXCEPT
1287        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1288    promise(const promise& __rhs) = delete;
1289    ~promise();
1290
1291    // assignment
1292    _LIBCPP_INLINE_VISIBILITY
1293    promise& operator=(promise&& __rhs) _NOEXCEPT
1294        {
1295            promise(_VSTD::move(__rhs)).swap(*this);
1296            return *this;
1297        }
1298    promise& operator=(const promise& __rhs) = delete;
1299
1300    _LIBCPP_INLINE_VISIBILITY
1301    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1302
1303    // retrieving the result
1304    future<_Rp> get_future();
1305
1306    // setting the result
1307    void set_value(const _Rp& __r);
1308    void set_value(_Rp&& __r);
1309    void set_exception(exception_ptr __p);
1310
1311    // setting the result with deferred notification
1312    void set_value_at_thread_exit(const _Rp& __r);
1313    void set_value_at_thread_exit(_Rp&& __r);
1314    void set_exception_at_thread_exit(exception_ptr __p);
1315};
1316
1317template <class _Rp>
1318promise<_Rp>::promise()
1319    : __state_(new __assoc_state<_Rp>)
1320{
1321}
1322
1323template <class _Rp>
1324template <class _Alloc>
1325promise<_Rp>::promise(allocator_arg_t, const _Alloc& __a0)
1326{
1327    typedef __assoc_state_alloc<_Rp, _Alloc> _State;
1328    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
1329    typedef __allocator_destructor<_A2> _D2;
1330    _A2 __a(__a0);
1331    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
1332    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
1333    __state_ = _VSTD::addressof(*__hold.release());
1334}
1335
1336template <class _Rp>
1337promise<_Rp>::~promise()
1338{
1339    if (__state_)
1340    {
1341        if (!__state_->__has_value() && __state_->use_count() > 1)
1342            __state_->set_exception(make_exception_ptr(
1343                      future_error(make_error_code(future_errc::broken_promise))
1344                                                      ));
1345        __state_->__release_shared();
1346    }
1347}
1348
1349template <class _Rp>
1350future<_Rp>
1351promise<_Rp>::get_future()
1352{
1353    if (__state_ == nullptr)
1354        __throw_future_error(future_errc::no_state);
1355    return future<_Rp>(__state_);
1356}
1357
1358template <class _Rp>
1359void
1360promise<_Rp>::set_value(const _Rp& __r)
1361{
1362    if (__state_ == nullptr)
1363        __throw_future_error(future_errc::no_state);
1364    __state_->set_value(__r);
1365}
1366
1367template <class _Rp>
1368void
1369promise<_Rp>::set_value(_Rp&& __r)
1370{
1371    if (__state_ == nullptr)
1372        __throw_future_error(future_errc::no_state);
1373    __state_->set_value(_VSTD::move(__r));
1374}
1375
1376template <class _Rp>
1377void
1378promise<_Rp>::set_exception(exception_ptr __p)
1379{
1380    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception: received nullptr" );
1381    if (__state_ == nullptr)
1382        __throw_future_error(future_errc::no_state);
1383    __state_->set_exception(__p);
1384}
1385
1386template <class _Rp>
1387void
1388promise<_Rp>::set_value_at_thread_exit(const _Rp& __r)
1389{
1390    if (__state_ == nullptr)
1391        __throw_future_error(future_errc::no_state);
1392    __state_->set_value_at_thread_exit(__r);
1393}
1394
1395template <class _Rp>
1396void
1397promise<_Rp>::set_value_at_thread_exit(_Rp&& __r)
1398{
1399    if (__state_ == nullptr)
1400        __throw_future_error(future_errc::no_state);
1401    __state_->set_value_at_thread_exit(_VSTD::move(__r));
1402}
1403
1404template <class _Rp>
1405void
1406promise<_Rp>::set_exception_at_thread_exit(exception_ptr __p)
1407{
1408    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception_at_thread_exit: received nullptr" );
1409    if (__state_ == nullptr)
1410        __throw_future_error(future_errc::no_state);
1411    __state_->set_exception_at_thread_exit(__p);
1412}
1413
1414// promise<R&>
1415
1416template <class _Rp>
1417class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE promise<_Rp&>
1418{
1419    __assoc_state<_Rp&>* __state_;
1420
1421    _LIBCPP_INLINE_VISIBILITY
1422    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
1423
1424    template <class> friend class packaged_task;
1425
1426public:
1427    promise();
1428    template <class _Allocator>
1429        promise(allocator_arg_t, const _Allocator& __a);
1430    _LIBCPP_INLINE_VISIBILITY
1431    promise(promise&& __rhs) _NOEXCEPT
1432        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1433    promise(const promise& __rhs) = delete;
1434    ~promise();
1435
1436    // assignment
1437    _LIBCPP_INLINE_VISIBILITY
1438    promise& operator=(promise&& __rhs) _NOEXCEPT
1439        {
1440            promise(_VSTD::move(__rhs)).swap(*this);
1441            return *this;
1442        }
1443    promise& operator=(const promise& __rhs) = delete;
1444
1445    _LIBCPP_INLINE_VISIBILITY
1446    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1447
1448    // retrieving the result
1449    future<_Rp&> get_future();
1450
1451    // setting the result
1452    void set_value(_Rp& __r);
1453    void set_exception(exception_ptr __p);
1454
1455    // setting the result with deferred notification
1456    void set_value_at_thread_exit(_Rp&);
1457    void set_exception_at_thread_exit(exception_ptr __p);
1458};
1459
1460template <class _Rp>
1461promise<_Rp&>::promise()
1462    : __state_(new __assoc_state<_Rp&>)
1463{
1464}
1465
1466template <class _Rp>
1467template <class _Alloc>
1468promise<_Rp&>::promise(allocator_arg_t, const _Alloc& __a0)
1469{
1470    typedef __assoc_state_alloc<_Rp&, _Alloc> _State;
1471    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
1472    typedef __allocator_destructor<_A2> _D2;
1473    _A2 __a(__a0);
1474    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
1475    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
1476    __state_ = _VSTD::addressof(*__hold.release());
1477}
1478
1479template <class _Rp>
1480promise<_Rp&>::~promise()
1481{
1482    if (__state_)
1483    {
1484        if (!__state_->__has_value() && __state_->use_count() > 1)
1485            __state_->set_exception(make_exception_ptr(
1486                      future_error(make_error_code(future_errc::broken_promise))
1487                                                      ));
1488        __state_->__release_shared();
1489    }
1490}
1491
1492template <class _Rp>
1493future<_Rp&>
1494promise<_Rp&>::get_future()
1495{
1496    if (__state_ == nullptr)
1497        __throw_future_error(future_errc::no_state);
1498    return future<_Rp&>(__state_);
1499}
1500
1501template <class _Rp>
1502void
1503promise<_Rp&>::set_value(_Rp& __r)
1504{
1505    if (__state_ == nullptr)
1506        __throw_future_error(future_errc::no_state);
1507    __state_->set_value(__r);
1508}
1509
1510template <class _Rp>
1511void
1512promise<_Rp&>::set_exception(exception_ptr __p)
1513{
1514    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception: received nullptr" );
1515    if (__state_ == nullptr)
1516        __throw_future_error(future_errc::no_state);
1517    __state_->set_exception(__p);
1518}
1519
1520template <class _Rp>
1521void
1522promise<_Rp&>::set_value_at_thread_exit(_Rp& __r)
1523{
1524    if (__state_ == nullptr)
1525        __throw_future_error(future_errc::no_state);
1526    __state_->set_value_at_thread_exit(__r);
1527}
1528
1529template <class _Rp>
1530void
1531promise<_Rp&>::set_exception_at_thread_exit(exception_ptr __p)
1532{
1533    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception_at_thread_exit: received nullptr" );
1534    if (__state_ == nullptr)
1535        __throw_future_error(future_errc::no_state);
1536    __state_->set_exception_at_thread_exit(__p);
1537}
1538
1539// promise<void>
1540
1541template <>
1542class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE promise<void>
1543{
1544    __assoc_sub_state* __state_;
1545
1546    _LIBCPP_INLINE_VISIBILITY
1547    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
1548
1549    template <class> friend class packaged_task;
1550
1551public:
1552    promise();
1553    template <class _Allocator>
1554        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
1555        promise(allocator_arg_t, const _Allocator& __a);
1556    _LIBCPP_INLINE_VISIBILITY
1557    promise(promise&& __rhs) _NOEXCEPT
1558        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1559    promise(const promise& __rhs) = delete;
1560    ~promise();
1561
1562    // assignment
1563    _LIBCPP_INLINE_VISIBILITY
1564    promise& operator=(promise&& __rhs) _NOEXCEPT
1565        {
1566            promise(_VSTD::move(__rhs)).swap(*this);
1567            return *this;
1568        }
1569    promise& operator=(const promise& __rhs) = delete;
1570
1571    _LIBCPP_INLINE_VISIBILITY
1572    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1573
1574    // retrieving the result
1575    future<void> get_future();
1576
1577    // setting the result
1578    void set_value();
1579    void set_exception(exception_ptr __p);
1580
1581    // setting the result with deferred notification
1582    void set_value_at_thread_exit();
1583    void set_exception_at_thread_exit(exception_ptr __p);
1584};
1585
1586template <class _Alloc>
1587promise<void>::promise(allocator_arg_t, const _Alloc& __a0)
1588{
1589    typedef __assoc_sub_state_alloc<_Alloc> _State;
1590    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
1591    typedef __allocator_destructor<_A2> _D2;
1592    _A2 __a(__a0);
1593    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
1594    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
1595    __state_ = _VSTD::addressof(*__hold.release());
1596}
1597
1598template <class _Rp>
1599inline _LIBCPP_INLINE_VISIBILITY
1600void
1601swap(promise<_Rp>& __x, promise<_Rp>& __y) _NOEXCEPT
1602{
1603    __x.swap(__y);
1604}
1605
1606template <class _Rp, class _Alloc>
1607    struct _LIBCPP_TEMPLATE_VIS uses_allocator<promise<_Rp>, _Alloc>
1608        : public true_type {};
1609
1610// packaged_task
1611
1612template<class _Fp> class __packaged_task_base;
1613
1614template<class _Rp, class ..._ArgTypes>
1615class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_base<_Rp(_ArgTypes...)>
1616{
1617    __packaged_task_base(const __packaged_task_base&);
1618    __packaged_task_base& operator=(const __packaged_task_base&);
1619public:
1620    _LIBCPP_INLINE_VISIBILITY
1621    __packaged_task_base() {}
1622    _LIBCPP_INLINE_VISIBILITY
1623    virtual ~__packaged_task_base() {}
1624    virtual void __move_to(__packaged_task_base*) _NOEXCEPT = 0;
1625    virtual void destroy() = 0;
1626    virtual void destroy_deallocate() = 0;
1627    virtual _Rp operator()(_ArgTypes&& ...) = 0;
1628};
1629
1630template<class _FD, class _Alloc, class _FB> class __packaged_task_func;
1631
1632template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1633class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>
1634    : public  __packaged_task_base<_Rp(_ArgTypes...)>
1635{
1636    __compressed_pair<_Fp, _Alloc> __f_;
1637public:
1638    _LIBCPP_INLINE_VISIBILITY
1639    explicit __packaged_task_func(const _Fp& __f) : __f_(__f, __default_init_tag()) {}
1640    _LIBCPP_INLINE_VISIBILITY
1641    explicit __packaged_task_func(_Fp&& __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
1642    _LIBCPP_INLINE_VISIBILITY
1643    __packaged_task_func(const _Fp& __f, const _Alloc& __a)
1644        : __f_(__f, __a) {}
1645    _LIBCPP_INLINE_VISIBILITY
1646    __packaged_task_func(_Fp&& __f, const _Alloc& __a)
1647        : __f_(_VSTD::move(__f), __a) {}
1648    virtual void __move_to(__packaged_task_base<_Rp(_ArgTypes...)>*) _NOEXCEPT;
1649    virtual void destroy();
1650    virtual void destroy_deallocate();
1651    virtual _Rp operator()(_ArgTypes&& ... __args);
1652};
1653
1654template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1655void
1656__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__move_to(
1657                              __packaged_task_base<_Rp(_ArgTypes...)>* __p) _NOEXCEPT
1658{
1659    ::new ((void*)__p) __packaged_task_func(_VSTD::move(__f_.first()), _VSTD::move(__f_.second()));
1660}
1661
1662template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1663void
1664__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy()
1665{
1666    __f_.~__compressed_pair<_Fp, _Alloc>();
1667}
1668
1669template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1670void
1671__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate()
1672{
1673    typedef typename __allocator_traits_rebind<_Alloc, __packaged_task_func>::type _Ap;
1674    typedef allocator_traits<_Ap> _ATraits;
1675    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
1676    _Ap __a(__f_.second());
1677    __f_.~__compressed_pair<_Fp, _Alloc>();
1678    __a.deallocate(_PTraits::pointer_to(*this), 1);
1679}
1680
1681template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1682_Rp
1683__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&& ... __arg)
1684{
1685    return _VSTD::__invoke(__f_.first(), _VSTD::forward<_ArgTypes>(__arg)...);
1686}
1687
1688template <class _Callable> class __packaged_task_function;
1689
1690template<class _Rp, class ..._ArgTypes>
1691class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_function<_Rp(_ArgTypes...)>
1692{
1693    typedef __packaged_task_base<_Rp(_ArgTypes...)> __base;
1694
1695    _LIBCPP_INLINE_VISIBILITY _LIBCPP_NO_CFI
1696    __base* __get_buf() { return (__base*)&__buf_; }
1697
1698    typename aligned_storage<3*sizeof(void*)>::type __buf_;
1699    __base* __f_;
1700
1701public:
1702    typedef _Rp result_type;
1703
1704    // construct/copy/destroy:
1705    _LIBCPP_INLINE_VISIBILITY
1706    __packaged_task_function() _NOEXCEPT : __f_(nullptr) {}
1707    template<class _Fp>
1708      __packaged_task_function(_Fp&& __f);
1709    template<class _Fp, class _Alloc>
1710      __packaged_task_function(allocator_arg_t, const _Alloc& __a, _Fp&& __f);
1711
1712    __packaged_task_function(__packaged_task_function&&) _NOEXCEPT;
1713    __packaged_task_function& operator=(__packaged_task_function&&) _NOEXCEPT;
1714
1715    __packaged_task_function(const __packaged_task_function&) =  delete;
1716    __packaged_task_function& operator=(const __packaged_task_function&) =  delete;
1717
1718    ~__packaged_task_function();
1719
1720    void swap(__packaged_task_function&) _NOEXCEPT;
1721
1722    _LIBCPP_INLINE_VISIBILITY
1723    _Rp operator()(_ArgTypes...) const;
1724};
1725
1726template<class _Rp, class ..._ArgTypes>
1727__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(__packaged_task_function&& __f) _NOEXCEPT
1728{
1729    if (__f.__f_ == nullptr)
1730        __f_ = nullptr;
1731    else if (__f.__f_ == __f.__get_buf())
1732    {
1733        __f.__f_->__move_to(__get_buf());
1734        __f_ = (__base*)&__buf_;
1735    }
1736    else
1737    {
1738        __f_ = __f.__f_;
1739        __f.__f_ = nullptr;
1740    }
1741}
1742
1743template<class _Rp, class ..._ArgTypes>
1744template <class _Fp>
1745__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(_Fp&& __f)
1746    : __f_(nullptr)
1747{
1748    typedef typename remove_reference<typename decay<_Fp>::type>::type _FR;
1749    typedef __packaged_task_func<_FR, allocator<_FR>, _Rp(_ArgTypes...)> _FF;
1750    if (sizeof(_FF) <= sizeof(__buf_))
1751    {
1752        ::new ((void*)&__buf_) _FF(_VSTD::forward<_Fp>(__f));
1753        __f_ = (__base*)&__buf_;
1754    }
1755    else
1756    {
1757        typedef allocator<_FF> _Ap;
1758        _Ap __a;
1759        typedef __allocator_destructor<_Ap> _Dp;
1760        unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
1761        ::new ((void*)__hold.get()) _FF(_VSTD::forward<_Fp>(__f), allocator<_FR>(__a));
1762        __f_ = __hold.release();
1763    }
1764}
1765
1766template<class _Rp, class ..._ArgTypes>
1767template <class _Fp, class _Alloc>
1768__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(
1769                                  allocator_arg_t, const _Alloc& __a0, _Fp&& __f)
1770    : __f_(nullptr)
1771{
1772    typedef typename remove_reference<typename decay<_Fp>::type>::type _FR;
1773    typedef __packaged_task_func<_FR, _Alloc, _Rp(_ArgTypes...)> _FF;
1774    if (sizeof(_FF) <= sizeof(__buf_))
1775    {
1776        __f_ = (__base*)&__buf_;
1777        ::new ((void*)__f_) _FF(_VSTD::forward<_Fp>(__f));
1778    }
1779    else
1780    {
1781        typedef typename __allocator_traits_rebind<_Alloc, _FF>::type _Ap;
1782        _Ap __a(__a0);
1783        typedef __allocator_destructor<_Ap> _Dp;
1784        unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
1785        ::new ((void*)_VSTD::addressof(*__hold.get()))
1786            _FF(_VSTD::forward<_Fp>(__f), _Alloc(__a));
1787        __f_ = _VSTD::addressof(*__hold.release());
1788    }
1789}
1790
1791template<class _Rp, class ..._ArgTypes>
1792__packaged_task_function<_Rp(_ArgTypes...)>&
1793__packaged_task_function<_Rp(_ArgTypes...)>::operator=(__packaged_task_function&& __f) _NOEXCEPT
1794{
1795    if (__f_ == __get_buf())
1796        __f_->destroy();
1797    else if (__f_)
1798        __f_->destroy_deallocate();
1799    __f_ = nullptr;
1800    if (__f.__f_ == nullptr)
1801        __f_ = nullptr;
1802    else if (__f.__f_ == __f.__get_buf())
1803    {
1804        __f.__f_->__move_to(__get_buf());
1805        __f_ = __get_buf();
1806    }
1807    else
1808    {
1809        __f_ = __f.__f_;
1810        __f.__f_ = nullptr;
1811    }
1812    return *this;
1813}
1814
1815template<class _Rp, class ..._ArgTypes>
1816__packaged_task_function<_Rp(_ArgTypes...)>::~__packaged_task_function()
1817{
1818    if (__f_ == __get_buf())
1819        __f_->destroy();
1820    else if (__f_)
1821        __f_->destroy_deallocate();
1822}
1823
1824template<class _Rp, class ..._ArgTypes>
1825_LIBCPP_NO_CFI
1826void
1827__packaged_task_function<_Rp(_ArgTypes...)>::swap(__packaged_task_function& __f) _NOEXCEPT
1828{
1829    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
1830    {
1831        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
1832        __base* __t = (__base*)&__tempbuf;
1833        __f_->__move_to(__t);
1834        __f_->destroy();
1835        __f_ = nullptr;
1836        __f.__f_->__move_to((__base*)&__buf_);
1837        __f.__f_->destroy();
1838        __f.__f_ = nullptr;
1839        __f_ = (__base*)&__buf_;
1840        __t->__move_to((__base*)&__f.__buf_);
1841        __t->destroy();
1842        __f.__f_ = (__base*)&__f.__buf_;
1843    }
1844    else if (__f_ == (__base*)&__buf_)
1845    {
1846        __f_->__move_to((__base*)&__f.__buf_);
1847        __f_->destroy();
1848        __f_ = __f.__f_;
1849        __f.__f_ = (__base*)&__f.__buf_;
1850    }
1851    else if (__f.__f_ == (__base*)&__f.__buf_)
1852    {
1853        __f.__f_->__move_to((__base*)&__buf_);
1854        __f.__f_->destroy();
1855        __f.__f_ = __f_;
1856        __f_ = (__base*)&__buf_;
1857    }
1858    else
1859        _VSTD::swap(__f_, __f.__f_);
1860}
1861
1862template<class _Rp, class ..._ArgTypes>
1863inline
1864_Rp
1865__packaged_task_function<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __arg) const
1866{
1867    return (*__f_)(_VSTD::forward<_ArgTypes>(__arg)...);
1868}
1869
1870template<class _Rp, class ..._ArgTypes>
1871class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE packaged_task<_Rp(_ArgTypes...)>
1872{
1873public:
1874    typedef _Rp result_type; // extension
1875
1876private:
1877    __packaged_task_function<result_type(_ArgTypes...)> __f_;
1878    promise<result_type>                                __p_;
1879
1880public:
1881    // construction and destruction
1882    _LIBCPP_INLINE_VISIBILITY
1883    packaged_task() _NOEXCEPT : __p_(nullptr) {}
1884    template <class _Fp,
1885              class = typename enable_if
1886              <
1887                  !is_same<
1888                      typename __uncvref<_Fp>::type,
1889                      packaged_task
1890                      >::value
1891                  >::type
1892             >
1893        _LIBCPP_INLINE_VISIBILITY
1894        explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
1895    template <class _Fp, class _Allocator,
1896              class = typename enable_if
1897              <
1898                  !is_same<
1899                      typename __uncvref<_Fp>::type,
1900                      packaged_task
1901                      >::value
1902                  >::type
1903              >
1904        _LIBCPP_INLINE_VISIBILITY
1905        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
1906             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
1907               __p_(allocator_arg, __a) {}
1908    // ~packaged_task() = default;
1909
1910    // no copy
1911    packaged_task(const packaged_task&) = delete;
1912    packaged_task& operator=(const packaged_task&) = delete;
1913
1914    // move support
1915    _LIBCPP_INLINE_VISIBILITY
1916    packaged_task(packaged_task&& __other) _NOEXCEPT
1917        : __f_(_VSTD::move(__other.__f_)), __p_(_VSTD::move(__other.__p_)) {}
1918    _LIBCPP_INLINE_VISIBILITY
1919    packaged_task& operator=(packaged_task&& __other) _NOEXCEPT
1920    {
1921        __f_ = _VSTD::move(__other.__f_);
1922        __p_ = _VSTD::move(__other.__p_);
1923        return *this;
1924    }
1925    _LIBCPP_INLINE_VISIBILITY
1926    void swap(packaged_task& __other) _NOEXCEPT
1927    {
1928        __f_.swap(__other.__f_);
1929        __p_.swap(__other.__p_);
1930    }
1931
1932    _LIBCPP_INLINE_VISIBILITY
1933    bool valid() const _NOEXCEPT {return __p_.__state_ != nullptr;}
1934
1935    // result retrieval
1936    _LIBCPP_INLINE_VISIBILITY
1937    future<result_type> get_future() {return __p_.get_future();}
1938
1939    // execution
1940    void operator()(_ArgTypes... __args);
1941    void make_ready_at_thread_exit(_ArgTypes... __args);
1942
1943    void reset();
1944};
1945
1946template<class _Rp, class ..._ArgTypes>
1947void
1948packaged_task<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __args)
1949{
1950    if (__p_.__state_ == nullptr)
1951        __throw_future_error(future_errc::no_state);
1952    if (__p_.__state_->__has_value())
1953        __throw_future_error(future_errc::promise_already_satisfied);
1954#ifndef _LIBCPP_NO_EXCEPTIONS
1955    try
1956    {
1957#endif // _LIBCPP_NO_EXCEPTIONS
1958        __p_.set_value(__f_(_VSTD::forward<_ArgTypes>(__args)...));
1959#ifndef _LIBCPP_NO_EXCEPTIONS
1960    }
1961    catch (...)
1962    {
1963        __p_.set_exception(current_exception());
1964    }
1965#endif // _LIBCPP_NO_EXCEPTIONS
1966}
1967
1968template<class _Rp, class ..._ArgTypes>
1969void
1970packaged_task<_Rp(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args)
1971{
1972    if (__p_.__state_ == nullptr)
1973        __throw_future_error(future_errc::no_state);
1974    if (__p_.__state_->__has_value())
1975        __throw_future_error(future_errc::promise_already_satisfied);
1976#ifndef _LIBCPP_NO_EXCEPTIONS
1977    try
1978    {
1979#endif // _LIBCPP_NO_EXCEPTIONS
1980        __p_.set_value_at_thread_exit(__f_(_VSTD::forward<_ArgTypes>(__args)...));
1981#ifndef _LIBCPP_NO_EXCEPTIONS
1982    }
1983    catch (...)
1984    {
1985        __p_.set_exception_at_thread_exit(current_exception());
1986    }
1987#endif // _LIBCPP_NO_EXCEPTIONS
1988}
1989
1990template<class _Rp, class ..._ArgTypes>
1991void
1992packaged_task<_Rp(_ArgTypes...)>::reset()
1993{
1994    if (!valid())
1995        __throw_future_error(future_errc::no_state);
1996    __p_ = promise<result_type>();
1997}
1998
1999template<class ..._ArgTypes>
2000class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE packaged_task<void(_ArgTypes...)>
2001{
2002public:
2003    typedef void result_type; // extension
2004
2005private:
2006    __packaged_task_function<result_type(_ArgTypes...)> __f_;
2007    promise<result_type>                                __p_;
2008
2009public:
2010    // construction and destruction
2011    _LIBCPP_INLINE_VISIBILITY
2012    packaged_task() _NOEXCEPT : __p_(nullptr) {}
2013    template <class _Fp,
2014              class = typename enable_if
2015              <
2016                  !is_same<
2017                      typename __uncvref<_Fp>::type,
2018                      packaged_task
2019                      >::value
2020                  >::type
2021              >
2022        _LIBCPP_INLINE_VISIBILITY
2023        explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
2024    template <class _Fp, class _Allocator,
2025              class = typename enable_if
2026              <
2027                  !is_same<
2028                      typename __uncvref<_Fp>::type,
2029                      packaged_task
2030                      >::value
2031                  >::type
2032              >
2033        _LIBCPP_INLINE_VISIBILITY
2034        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
2035             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
2036               __p_(allocator_arg, __a) {}
2037    // ~packaged_task() = default;
2038
2039    // no copy
2040    packaged_task(const packaged_task&) = delete;
2041    packaged_task& operator=(const packaged_task&) = delete;
2042
2043    // move support
2044    _LIBCPP_INLINE_VISIBILITY
2045    packaged_task(packaged_task&& __other) _NOEXCEPT
2046        : __f_(_VSTD::move(__other.__f_)), __p_(_VSTD::move(__other.__p_)) {}
2047    _LIBCPP_INLINE_VISIBILITY
2048    packaged_task& operator=(packaged_task&& __other) _NOEXCEPT
2049    {
2050        __f_ = _VSTD::move(__other.__f_);
2051        __p_ = _VSTD::move(__other.__p_);
2052        return *this;
2053    }
2054    _LIBCPP_INLINE_VISIBILITY
2055    void swap(packaged_task& __other) _NOEXCEPT
2056    {
2057        __f_.swap(__other.__f_);
2058        __p_.swap(__other.__p_);
2059    }
2060
2061    _LIBCPP_INLINE_VISIBILITY
2062    bool valid() const _NOEXCEPT {return __p_.__state_ != nullptr;}
2063
2064    // result retrieval
2065    _LIBCPP_INLINE_VISIBILITY
2066    future<result_type> get_future() {return __p_.get_future();}
2067
2068    // execution
2069    void operator()(_ArgTypes... __args);
2070    void make_ready_at_thread_exit(_ArgTypes... __args);
2071
2072    void reset();
2073};
2074
2075template<class ..._ArgTypes>
2076void
2077packaged_task<void(_ArgTypes...)>::operator()(_ArgTypes... __args)
2078{
2079    if (__p_.__state_ == nullptr)
2080        __throw_future_error(future_errc::no_state);
2081    if (__p_.__state_->__has_value())
2082        __throw_future_error(future_errc::promise_already_satisfied);
2083#ifndef _LIBCPP_NO_EXCEPTIONS
2084    try
2085    {
2086#endif // _LIBCPP_NO_EXCEPTIONS
2087        __f_(_VSTD::forward<_ArgTypes>(__args)...);
2088        __p_.set_value();
2089#ifndef _LIBCPP_NO_EXCEPTIONS
2090    }
2091    catch (...)
2092    {
2093        __p_.set_exception(current_exception());
2094    }
2095#endif // _LIBCPP_NO_EXCEPTIONS
2096}
2097
2098template<class ..._ArgTypes>
2099void
2100packaged_task<void(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args)
2101{
2102    if (__p_.__state_ == nullptr)
2103        __throw_future_error(future_errc::no_state);
2104    if (__p_.__state_->__has_value())
2105        __throw_future_error(future_errc::promise_already_satisfied);
2106#ifndef _LIBCPP_NO_EXCEPTIONS
2107    try
2108    {
2109#endif // _LIBCPP_NO_EXCEPTIONS
2110        __f_(_VSTD::forward<_ArgTypes>(__args)...);
2111        __p_.set_value_at_thread_exit();
2112#ifndef _LIBCPP_NO_EXCEPTIONS
2113    }
2114    catch (...)
2115    {
2116        __p_.set_exception_at_thread_exit(current_exception());
2117    }
2118#endif // _LIBCPP_NO_EXCEPTIONS
2119}
2120
2121template<class ..._ArgTypes>
2122void
2123packaged_task<void(_ArgTypes...)>::reset()
2124{
2125    if (!valid())
2126        __throw_future_error(future_errc::no_state);
2127    __p_ = promise<result_type>();
2128}
2129
2130template <class _Rp, class... _ArgTypes>
2131inline _LIBCPP_INLINE_VISIBILITY
2132void
2133swap(packaged_task<_Rp(_ArgTypes...)>& __x, packaged_task<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
2134{
2135    __x.swap(__y);
2136}
2137
2138template <class _Callable, class _Alloc>
2139struct _LIBCPP_TEMPLATE_VIS uses_allocator<packaged_task<_Callable>, _Alloc>
2140    : public true_type {};
2141
2142template <class _Rp, class _Fp>
2143_LIBCPP_INLINE_VISIBILITY future<_Rp>
2144__make_deferred_assoc_state(_Fp&& __f)
2145{
2146    unique_ptr<__deferred_assoc_state<_Rp, _Fp>, __release_shared_count>
2147        __h(new __deferred_assoc_state<_Rp, _Fp>(_VSTD::forward<_Fp>(__f)));
2148    return future<_Rp>(__h.get());
2149}
2150
2151template <class _Rp, class _Fp>
2152_LIBCPP_INLINE_VISIBILITY future<_Rp>
2153__make_async_assoc_state(_Fp&& __f)
2154{
2155    unique_ptr<__async_assoc_state<_Rp, _Fp>, __release_shared_count>
2156        __h(new __async_assoc_state<_Rp, _Fp>(_VSTD::forward<_Fp>(__f)));
2157    _VSTD::thread(&__async_assoc_state<_Rp, _Fp>::__execute, __h.get()).detach();
2158    return future<_Rp>(__h.get());
2159}
2160
2161#ifndef _LIBCPP_CXX03_LANG
2162
2163template <class _Fp, class... _Args>
2164class _LIBCPP_HIDDEN __async_func
2165{
2166    tuple<_Fp, _Args...> __f_;
2167
2168public:
2169    typedef typename __invoke_of<_Fp, _Args...>::type _Rp;
2170
2171    _LIBCPP_INLINE_VISIBILITY
2172    explicit __async_func(_Fp&& __f, _Args&&... __args)
2173        : __f_(_VSTD::move(__f), _VSTD::move(__args)...) {}
2174
2175    _LIBCPP_INLINE_VISIBILITY
2176    __async_func(__async_func&& __f) : __f_(_VSTD::move(__f.__f_)) {}
2177
2178    _Rp operator()()
2179    {
2180        typedef typename __make_tuple_indices<1+sizeof...(_Args), 1>::type _Index;
2181        return __execute(_Index());
2182    }
2183private:
2184    template <size_t ..._Indices>
2185    _Rp
2186    __execute(__tuple_indices<_Indices...>)
2187    {
2188        return _VSTD::__invoke(_VSTD::move(_VSTD::get<0>(__f_)), _VSTD::move(_VSTD::get<_Indices>(__f_))...);
2189    }
2190};
2191
2192inline _LIBCPP_INLINE_VISIBILITY bool __does_policy_contain(launch __policy, launch __value )
2193{ return (int(__policy) & int(__value)) != 0; }
2194
2195template <class _Fp, class... _Args>
2196_LIBCPP_NODISCARD_AFTER_CXX17
2197future<typename __invoke_of<typename decay<_Fp>::type, typename decay<_Args>::type...>::type>
2198async(launch __policy, _Fp&& __f, _Args&&... __args)
2199{
2200    typedef __async_func<typename decay<_Fp>::type, typename decay<_Args>::type...> _BF;
2201    typedef typename _BF::_Rp _Rp;
2202
2203#ifndef _LIBCPP_NO_EXCEPTIONS
2204    try
2205    {
2206#endif
2207        if (__does_policy_contain(__policy, launch::async))
2208        return _VSTD::__make_async_assoc_state<_Rp>(_BF(_VSTD::__decay_copy(_VSTD::forward<_Fp>(__f)),
2209                                                     _VSTD::__decay_copy(_VSTD::forward<_Args>(__args))...));
2210#ifndef _LIBCPP_NO_EXCEPTIONS
2211    }
2212    catch ( ... ) { if (__policy == launch::async) throw ; }
2213#endif
2214
2215    if (__does_policy_contain(__policy, launch::deferred))
2216        return _VSTD::__make_deferred_assoc_state<_Rp>(_BF(_VSTD::__decay_copy(_VSTD::forward<_Fp>(__f)),
2217                                                        _VSTD::__decay_copy(_VSTD::forward<_Args>(__args))...));
2218    return future<_Rp>{};
2219}
2220
2221template <class _Fp, class... _Args>
2222_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY
2223future<typename __invoke_of<typename decay<_Fp>::type, typename decay<_Args>::type...>::type>
2224async(_Fp&& __f, _Args&&... __args)
2225{
2226    return _VSTD::async(launch::any, _VSTD::forward<_Fp>(__f),
2227                                    _VSTD::forward<_Args>(__args)...);
2228}
2229
2230#endif // C++03
2231
2232// shared_future
2233
2234template <class _Rp>
2235class _LIBCPP_TEMPLATE_VIS shared_future
2236{
2237    __assoc_state<_Rp>* __state_;
2238
2239public:
2240    _LIBCPP_INLINE_VISIBILITY
2241    shared_future() _NOEXCEPT : __state_(nullptr) {}
2242    _LIBCPP_INLINE_VISIBILITY
2243    shared_future(const shared_future& __rhs)  _NOEXCEPT : __state_(__rhs.__state_)
2244        {if (__state_) __state_->__add_shared();}
2245    _LIBCPP_INLINE_VISIBILITY
2246    shared_future(future<_Rp>&& __f) _NOEXCEPT : __state_(__f.__state_)
2247        {__f.__state_ = nullptr;}
2248    _LIBCPP_INLINE_VISIBILITY
2249    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
2250        {__rhs.__state_ = nullptr;}
2251    ~shared_future();
2252    shared_future& operator=(const shared_future& __rhs) _NOEXCEPT;
2253    _LIBCPP_INLINE_VISIBILITY
2254    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
2255        {
2256            shared_future(_VSTD::move(__rhs)).swap(*this);
2257            return *this;
2258        }
2259
2260    // retrieving the value
2261    _LIBCPP_INLINE_VISIBILITY
2262    const _Rp& get() const {return __state_->copy();}
2263
2264    _LIBCPP_INLINE_VISIBILITY
2265    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
2266
2267    // functions to check state
2268    _LIBCPP_INLINE_VISIBILITY
2269    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
2270
2271    _LIBCPP_INLINE_VISIBILITY
2272    void wait() const {__state_->wait();}
2273    template <class _Rep, class _Period>
2274        _LIBCPP_INLINE_VISIBILITY
2275        future_status
2276        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
2277            {return __state_->wait_for(__rel_time);}
2278    template <class _Clock, class _Duration>
2279        _LIBCPP_INLINE_VISIBILITY
2280        future_status
2281        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
2282            {return __state_->wait_until(__abs_time);}
2283};
2284
2285template <class _Rp>
2286shared_future<_Rp>::~shared_future()
2287{
2288    if (__state_)
2289        __state_->__release_shared();
2290}
2291
2292template <class _Rp>
2293shared_future<_Rp>&
2294shared_future<_Rp>::operator=(const shared_future& __rhs) _NOEXCEPT
2295{
2296    if (__rhs.__state_)
2297        __rhs.__state_->__add_shared();
2298    if (__state_)
2299        __state_->__release_shared();
2300    __state_ = __rhs.__state_;
2301    return *this;
2302}
2303
2304template <class _Rp>
2305class _LIBCPP_TEMPLATE_VIS shared_future<_Rp&>
2306{
2307    __assoc_state<_Rp&>* __state_;
2308
2309public:
2310    _LIBCPP_INLINE_VISIBILITY
2311    shared_future() _NOEXCEPT : __state_(nullptr) {}
2312    _LIBCPP_INLINE_VISIBILITY
2313    shared_future(const shared_future& __rhs) : __state_(__rhs.__state_)
2314        {if (__state_) __state_->__add_shared();}
2315    _LIBCPP_INLINE_VISIBILITY
2316    shared_future(future<_Rp&>&& __f) _NOEXCEPT : __state_(__f.__state_)
2317        {__f.__state_ = nullptr;}
2318    _LIBCPP_INLINE_VISIBILITY
2319    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
2320        {__rhs.__state_ = nullptr;}
2321    ~shared_future();
2322    shared_future& operator=(const shared_future& __rhs);
2323    _LIBCPP_INLINE_VISIBILITY
2324    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
2325        {
2326            shared_future(_VSTD::move(__rhs)).swap(*this);
2327            return *this;
2328        }
2329
2330    // retrieving the value
2331    _LIBCPP_INLINE_VISIBILITY
2332    _Rp& get() const {return __state_->copy();}
2333
2334    _LIBCPP_INLINE_VISIBILITY
2335    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
2336
2337    // functions to check state
2338    _LIBCPP_INLINE_VISIBILITY
2339    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
2340
2341    _LIBCPP_INLINE_VISIBILITY
2342    void wait() const {__state_->wait();}
2343    template <class _Rep, class _Period>
2344        _LIBCPP_INLINE_VISIBILITY
2345        future_status
2346        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
2347            {return __state_->wait_for(__rel_time);}
2348    template <class _Clock, class _Duration>
2349        _LIBCPP_INLINE_VISIBILITY
2350        future_status
2351        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
2352            {return __state_->wait_until(__abs_time);}
2353};
2354
2355template <class _Rp>
2356shared_future<_Rp&>::~shared_future()
2357{
2358    if (__state_)
2359        __state_->__release_shared();
2360}
2361
2362template <class _Rp>
2363shared_future<_Rp&>&
2364shared_future<_Rp&>::operator=(const shared_future& __rhs)
2365{
2366    if (__rhs.__state_)
2367        __rhs.__state_->__add_shared();
2368    if (__state_)
2369        __state_->__release_shared();
2370    __state_ = __rhs.__state_;
2371    return *this;
2372}
2373
2374template <>
2375class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE shared_future<void>
2376{
2377    __assoc_sub_state* __state_;
2378
2379public:
2380    _LIBCPP_INLINE_VISIBILITY
2381    shared_future() _NOEXCEPT : __state_(nullptr) {}
2382    _LIBCPP_INLINE_VISIBILITY
2383    shared_future(const shared_future& __rhs) : __state_(__rhs.__state_)
2384        {if (__state_) __state_->__add_shared();}
2385    _LIBCPP_INLINE_VISIBILITY
2386    shared_future(future<void>&& __f) _NOEXCEPT : __state_(__f.__state_)
2387        {__f.__state_ = nullptr;}
2388    _LIBCPP_INLINE_VISIBILITY
2389    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
2390        {__rhs.__state_ = nullptr;}
2391    ~shared_future();
2392    shared_future& operator=(const shared_future& __rhs);
2393    _LIBCPP_INLINE_VISIBILITY
2394    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
2395        {
2396            shared_future(_VSTD::move(__rhs)).swap(*this);
2397            return *this;
2398        }
2399
2400    // retrieving the value
2401    _LIBCPP_INLINE_VISIBILITY
2402    void get() const {__state_->copy();}
2403
2404    _LIBCPP_INLINE_VISIBILITY
2405    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
2406
2407    // functions to check state
2408    _LIBCPP_INLINE_VISIBILITY
2409    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
2410
2411    _LIBCPP_INLINE_VISIBILITY
2412    void wait() const {__state_->wait();}
2413    template <class _Rep, class _Period>
2414        _LIBCPP_INLINE_VISIBILITY
2415        future_status
2416        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
2417            {return __state_->wait_for(__rel_time);}
2418    template <class _Clock, class _Duration>
2419        _LIBCPP_INLINE_VISIBILITY
2420        future_status
2421        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
2422            {return __state_->wait_until(__abs_time);}
2423};
2424
2425template <class _Rp>
2426inline _LIBCPP_INLINE_VISIBILITY
2427void
2428swap(shared_future<_Rp>& __x, shared_future<_Rp>& __y) _NOEXCEPT
2429{
2430    __x.swap(__y);
2431}
2432
2433template <class _Rp>
2434inline
2435shared_future<_Rp>
2436future<_Rp>::share() _NOEXCEPT
2437{
2438    return shared_future<_Rp>(_VSTD::move(*this));
2439}
2440
2441template <class _Rp>
2442inline
2443shared_future<_Rp&>
2444future<_Rp&>::share() _NOEXCEPT
2445{
2446    return shared_future<_Rp&>(_VSTD::move(*this));
2447}
2448
2449inline
2450shared_future<void>
2451future<void>::share() _NOEXCEPT
2452{
2453    return shared_future<void>(_VSTD::move(*this));
2454}
2455
2456_LIBCPP_END_NAMESPACE_STD
2457
2458#endif // !_LIBCPP_HAS_NO_THREADS
2459
2460#endif // _LIBCPP_FUTURE
2461