xref: /freebsd/contrib/llvm-project/libcxx/include/future (revision d4eeb02986980bf33dd56c41ceb9fc5f180c0d47)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
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 <__memory/allocator_arg_t.h>
368#include <__memory/uses_allocator.h>
369#include <__utility/auto_cast.h>
370#include <__utility/forward.h>
371#include <chrono>
372#include <exception>
373#include <memory>
374#include <mutex>
375#include <system_error>
376#include <thread>
377#include <version>
378
379#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
380#pragma GCC system_header
381#endif
382
383#ifdef _LIBCPP_HAS_NO_THREADS
384#error <future> is not supported on this single threaded system
385#else // !_LIBCPP_HAS_NO_THREADS
386
387_LIBCPP_BEGIN_NAMESPACE_STD
388
389//enum class future_errc
390_LIBCPP_DECLARE_STRONG_ENUM(future_errc)
391{
392    future_already_retrieved = 1,
393    promise_already_satisfied,
394    no_state,
395    broken_promise
396};
397_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_errc)
398
399template <>
400struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc> : public true_type {};
401
402#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
403template <>
404struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc::__lx> : public true_type { };
405#endif
406
407//enum class launch
408_LIBCPP_DECLARE_STRONG_ENUM(launch)
409{
410    async = 1,
411    deferred = 2,
412    any = async | deferred
413};
414_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(launch)
415
416#ifndef _LIBCPP_HAS_NO_STRONG_ENUMS
417
418typedef underlying_type<launch>::type __launch_underlying_type;
419
420inline _LIBCPP_INLINE_VISIBILITY
421_LIBCPP_CONSTEXPR
422launch
423operator&(launch __x, launch __y)
424{
425    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) &
426                               static_cast<__launch_underlying_type>(__y));
427}
428
429inline _LIBCPP_INLINE_VISIBILITY
430_LIBCPP_CONSTEXPR
431launch
432operator|(launch __x, launch __y)
433{
434    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) |
435                               static_cast<__launch_underlying_type>(__y));
436}
437
438inline _LIBCPP_INLINE_VISIBILITY
439_LIBCPP_CONSTEXPR
440launch
441operator^(launch __x, launch __y)
442{
443    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) ^
444                               static_cast<__launch_underlying_type>(__y));
445}
446
447inline _LIBCPP_INLINE_VISIBILITY
448_LIBCPP_CONSTEXPR
449launch
450operator~(launch __x)
451{
452    return static_cast<launch>(~static_cast<__launch_underlying_type>(__x) & 3);
453}
454
455inline _LIBCPP_INLINE_VISIBILITY
456launch&
457operator&=(launch& __x, launch __y)
458{
459    __x = __x & __y; return __x;
460}
461
462inline _LIBCPP_INLINE_VISIBILITY
463launch&
464operator|=(launch& __x, launch __y)
465{
466    __x = __x | __y; return __x;
467}
468
469inline _LIBCPP_INLINE_VISIBILITY
470launch&
471operator^=(launch& __x, launch __y)
472{
473    __x = __x ^ __y; return __x;
474}
475
476#endif // !_LIBCPP_HAS_NO_STRONG_ENUMS
477
478//enum class future_status
479_LIBCPP_DECLARE_STRONG_ENUM(future_status)
480{
481    ready,
482    timeout,
483    deferred
484};
485_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_status)
486
487_LIBCPP_FUNC_VIS
488const error_category& future_category() _NOEXCEPT;
489
490inline _LIBCPP_INLINE_VISIBILITY
491error_code
492make_error_code(future_errc __e) _NOEXCEPT
493{
494    return error_code(static_cast<int>(__e), future_category());
495}
496
497inline _LIBCPP_INLINE_VISIBILITY
498error_condition
499make_error_condition(future_errc __e) _NOEXCEPT
500{
501    return error_condition(static_cast<int>(__e), future_category());
502}
503
504class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_FUTURE_ERROR future_error
505    : public logic_error
506{
507    error_code __ec_;
508public:
509    future_error(error_code __ec);
510
511    _LIBCPP_INLINE_VISIBILITY
512    const error_code& code() const _NOEXCEPT {return __ec_;}
513
514    future_error(const future_error&) _NOEXCEPT = default;
515    virtual ~future_error() _NOEXCEPT;
516};
517
518_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
519#ifndef _LIBCPP_NO_EXCEPTIONS
520_LIBCPP_AVAILABILITY_FUTURE_ERROR
521#endif
522void __throw_future_error(future_errc _Ev)
523{
524#ifndef _LIBCPP_NO_EXCEPTIONS
525    throw future_error(make_error_code(_Ev));
526#else
527    ((void)_Ev);
528    _VSTD::abort();
529#endif
530}
531
532class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE __assoc_sub_state
533    : public __shared_count
534{
535protected:
536    exception_ptr __exception_;
537    mutable mutex __mut_;
538    mutable condition_variable __cv_;
539    unsigned __state_;
540
541    virtual void __on_zero_shared() _NOEXCEPT;
542    void __sub_wait(unique_lock<mutex>& __lk);
543public:
544    enum
545    {
546        __constructed = 1,
547        __future_attached = 2,
548        ready = 4,
549        deferred = 8
550    };
551
552    _LIBCPP_INLINE_VISIBILITY
553    __assoc_sub_state() : __state_(0) {}
554
555    _LIBCPP_INLINE_VISIBILITY
556    bool __has_value() const
557        {return (__state_ & __constructed) || (__exception_ != nullptr);}
558
559    _LIBCPP_INLINE_VISIBILITY
560    void __attach_future() {
561        lock_guard<mutex> __lk(__mut_);
562        bool __has_future_attached = (__state_ & __future_attached) != 0;
563        if (__has_future_attached)
564            __throw_future_error(future_errc::future_already_retrieved);
565        this->__add_shared();
566        __state_ |= __future_attached;
567    }
568
569    _LIBCPP_INLINE_VISIBILITY
570    void __set_deferred() {__state_ |= deferred;}
571
572    void __make_ready();
573    _LIBCPP_INLINE_VISIBILITY
574    bool __is_ready() const {return (__state_ & ready) != 0;}
575
576    void set_value();
577    void set_value_at_thread_exit();
578
579    void set_exception(exception_ptr __p);
580    void set_exception_at_thread_exit(exception_ptr __p);
581
582    void copy();
583
584    void wait();
585    template <class _Rep, class _Period>
586        future_status
587        _LIBCPP_INLINE_VISIBILITY
588        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const;
589    template <class _Clock, class _Duration>
590        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
591        future_status
592        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const;
593
594    virtual void __execute();
595};
596
597template <class _Clock, class _Duration>
598future_status
599__assoc_sub_state::wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
600{
601    unique_lock<mutex> __lk(__mut_);
602    if (__state_ & deferred)
603        return future_status::deferred;
604    while (!(__state_ & ready) && _Clock::now() < __abs_time)
605        __cv_.wait_until(__lk, __abs_time);
606    if (__state_ & ready)
607        return future_status::ready;
608    return future_status::timeout;
609}
610
611template <class _Rep, class _Period>
612inline
613future_status
614__assoc_sub_state::wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
615{
616    return wait_until(chrono::steady_clock::now() + __rel_time);
617}
618
619template <class _Rp>
620class _LIBCPP_AVAILABILITY_FUTURE _LIBCPP_HIDDEN __assoc_state
621    : public __assoc_sub_state
622{
623    typedef __assoc_sub_state base;
624    typedef typename aligned_storage<sizeof(_Rp), alignment_of<_Rp>::value>::type _Up;
625protected:
626    _Up __value_;
627
628    virtual void __on_zero_shared() _NOEXCEPT;
629public:
630
631    template <class _Arg>
632    void set_value(_Arg&& __arg);
633
634    template <class _Arg>
635    void set_value_at_thread_exit(_Arg&& __arg);
636
637    _Rp move();
638    typename add_lvalue_reference<_Rp>::type copy();
639};
640
641template <class _Rp>
642void
643__assoc_state<_Rp>::__on_zero_shared() _NOEXCEPT
644{
645    if (this->__state_ & base::__constructed)
646        reinterpret_cast<_Rp*>(&__value_)->~_Rp();
647    delete this;
648}
649
650template <class _Rp>
651template <class _Arg>
652_LIBCPP_AVAILABILITY_FUTURE
653void
654__assoc_state<_Rp>::set_value(_Arg&& __arg)
655{
656    unique_lock<mutex> __lk(this->__mut_);
657    if (this->__has_value())
658        __throw_future_error(future_errc::promise_already_satisfied);
659    ::new ((void*)&__value_) _Rp(_VSTD::forward<_Arg>(__arg));
660    this->__state_ |= base::__constructed | base::ready;
661    __cv_.notify_all();
662}
663
664template <class _Rp>
665template <class _Arg>
666void
667__assoc_state<_Rp>::set_value_at_thread_exit(_Arg&& __arg)
668{
669    unique_lock<mutex> __lk(this->__mut_);
670    if (this->__has_value())
671        __throw_future_error(future_errc::promise_already_satisfied);
672    ::new ((void*)&__value_) _Rp(_VSTD::forward<_Arg>(__arg));
673    this->__state_ |= base::__constructed;
674    __thread_local_data()->__make_ready_at_thread_exit(this);
675}
676
677template <class _Rp>
678_Rp
679__assoc_state<_Rp>::move()
680{
681    unique_lock<mutex> __lk(this->__mut_);
682    this->__sub_wait(__lk);
683    if (this->__exception_ != nullptr)
684        rethrow_exception(this->__exception_);
685    return _VSTD::move(*reinterpret_cast<_Rp*>(&__value_));
686}
687
688template <class _Rp>
689typename add_lvalue_reference<_Rp>::type
690__assoc_state<_Rp>::copy()
691{
692    unique_lock<mutex> __lk(this->__mut_);
693    this->__sub_wait(__lk);
694    if (this->__exception_ != nullptr)
695        rethrow_exception(this->__exception_);
696    return *reinterpret_cast<_Rp*>(&__value_);
697}
698
699template <class _Rp>
700class _LIBCPP_AVAILABILITY_FUTURE __assoc_state<_Rp&>
701    : public __assoc_sub_state
702{
703    typedef __assoc_sub_state base;
704    typedef _Rp* _Up;
705protected:
706    _Up __value_;
707
708    virtual void __on_zero_shared() _NOEXCEPT;
709public:
710
711    void set_value(_Rp& __arg);
712    void set_value_at_thread_exit(_Rp& __arg);
713
714    _Rp& copy();
715};
716
717template <class _Rp>
718void
719__assoc_state<_Rp&>::__on_zero_shared() _NOEXCEPT
720{
721    delete this;
722}
723
724template <class _Rp>
725void
726__assoc_state<_Rp&>::set_value(_Rp& __arg)
727{
728    unique_lock<mutex> __lk(this->__mut_);
729    if (this->__has_value())
730        __throw_future_error(future_errc::promise_already_satisfied);
731    __value_ = _VSTD::addressof(__arg);
732    this->__state_ |= base::__constructed | base::ready;
733    __cv_.notify_all();
734}
735
736template <class _Rp>
737void
738__assoc_state<_Rp&>::set_value_at_thread_exit(_Rp& __arg)
739{
740    unique_lock<mutex> __lk(this->__mut_);
741    if (this->__has_value())
742        __throw_future_error(future_errc::promise_already_satisfied);
743    __value_ = _VSTD::addressof(__arg);
744    this->__state_ |= base::__constructed;
745    __thread_local_data()->__make_ready_at_thread_exit(this);
746}
747
748template <class _Rp>
749_Rp&
750__assoc_state<_Rp&>::copy()
751{
752    unique_lock<mutex> __lk(this->__mut_);
753    this->__sub_wait(__lk);
754    if (this->__exception_ != nullptr)
755        rethrow_exception(this->__exception_);
756    return *__value_;
757}
758
759template <class _Rp, class _Alloc>
760class _LIBCPP_AVAILABILITY_FUTURE __assoc_state_alloc
761    : public __assoc_state<_Rp>
762{
763    typedef __assoc_state<_Rp> base;
764    _Alloc __alloc_;
765
766    virtual void __on_zero_shared() _NOEXCEPT;
767public:
768    _LIBCPP_INLINE_VISIBILITY
769    explicit __assoc_state_alloc(const _Alloc& __a)
770        : __alloc_(__a) {}
771};
772
773template <class _Rp, class _Alloc>
774void
775__assoc_state_alloc<_Rp, _Alloc>::__on_zero_shared() _NOEXCEPT
776{
777    if (this->__state_ & base::__constructed)
778        reinterpret_cast<_Rp*>(_VSTD::addressof(this->__value_))->~_Rp();
779    typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;
780    typedef allocator_traits<_Al> _ATraits;
781    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
782    _Al __a(__alloc_);
783    this->~__assoc_state_alloc();
784    __a.deallocate(_PTraits::pointer_to(*this), 1);
785}
786
787template <class _Rp, class _Alloc>
788class _LIBCPP_AVAILABILITY_FUTURE __assoc_state_alloc<_Rp&, _Alloc>
789    : public __assoc_state<_Rp&>
790{
791    typedef __assoc_state<_Rp&> base;
792    _Alloc __alloc_;
793
794    virtual void __on_zero_shared() _NOEXCEPT;
795public:
796    _LIBCPP_INLINE_VISIBILITY
797    explicit __assoc_state_alloc(const _Alloc& __a)
798        : __alloc_(__a) {}
799};
800
801template <class _Rp, class _Alloc>
802void
803__assoc_state_alloc<_Rp&, _Alloc>::__on_zero_shared() _NOEXCEPT
804{
805    typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;
806    typedef allocator_traits<_Al> _ATraits;
807    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
808    _Al __a(__alloc_);
809    this->~__assoc_state_alloc();
810    __a.deallocate(_PTraits::pointer_to(*this), 1);
811}
812
813template <class _Alloc>
814class _LIBCPP_AVAILABILITY_FUTURE __assoc_sub_state_alloc
815    : public __assoc_sub_state
816{
817    typedef __assoc_sub_state base;
818    _Alloc __alloc_;
819
820    virtual void __on_zero_shared() _NOEXCEPT;
821public:
822    _LIBCPP_INLINE_VISIBILITY
823    explicit __assoc_sub_state_alloc(const _Alloc& __a)
824        : __alloc_(__a) {}
825};
826
827template <class _Alloc>
828void
829__assoc_sub_state_alloc<_Alloc>::__on_zero_shared() _NOEXCEPT
830{
831    typedef typename __allocator_traits_rebind<_Alloc, __assoc_sub_state_alloc>::type _Al;
832    typedef allocator_traits<_Al> _ATraits;
833    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
834    _Al __a(__alloc_);
835    this->~__assoc_sub_state_alloc();
836    __a.deallocate(_PTraits::pointer_to(*this), 1);
837}
838
839template <class _Rp, class _Fp>
840class _LIBCPP_AVAILABILITY_FUTURE __deferred_assoc_state
841    : public __assoc_state<_Rp>
842{
843    typedef __assoc_state<_Rp> base;
844
845    _Fp __func_;
846
847public:
848    _LIBCPP_INLINE_VISIBILITY
849    explicit __deferred_assoc_state(_Fp&& __f);
850
851    virtual void __execute();
852};
853
854template <class _Rp, class _Fp>
855inline
856__deferred_assoc_state<_Rp, _Fp>::__deferred_assoc_state(_Fp&& __f)
857    : __func_(_VSTD::forward<_Fp>(__f))
858{
859    this->__set_deferred();
860}
861
862template <class _Rp, class _Fp>
863void
864__deferred_assoc_state<_Rp, _Fp>::__execute()
865{
866#ifndef _LIBCPP_NO_EXCEPTIONS
867    try
868    {
869#endif // _LIBCPP_NO_EXCEPTIONS
870        this->set_value(__func_());
871#ifndef _LIBCPP_NO_EXCEPTIONS
872    }
873    catch (...)
874    {
875        this->set_exception(current_exception());
876    }
877#endif // _LIBCPP_NO_EXCEPTIONS
878}
879
880template <class _Fp>
881class _LIBCPP_AVAILABILITY_FUTURE __deferred_assoc_state<void, _Fp>
882    : public __assoc_sub_state
883{
884    typedef __assoc_sub_state base;
885
886    _Fp __func_;
887
888public:
889    _LIBCPP_INLINE_VISIBILITY
890    explicit __deferred_assoc_state(_Fp&& __f);
891
892    virtual void __execute();
893};
894
895template <class _Fp>
896inline
897__deferred_assoc_state<void, _Fp>::__deferred_assoc_state(_Fp&& __f)
898    : __func_(_VSTD::forward<_Fp>(__f))
899{
900    this->__set_deferred();
901}
902
903template <class _Fp>
904void
905__deferred_assoc_state<void, _Fp>::__execute()
906{
907#ifndef _LIBCPP_NO_EXCEPTIONS
908    try
909    {
910#endif // _LIBCPP_NO_EXCEPTIONS
911        __func_();
912        this->set_value();
913#ifndef _LIBCPP_NO_EXCEPTIONS
914    }
915    catch (...)
916    {
917        this->set_exception(current_exception());
918    }
919#endif // _LIBCPP_NO_EXCEPTIONS
920}
921
922template <class _Rp, class _Fp>
923class _LIBCPP_AVAILABILITY_FUTURE __async_assoc_state
924    : public __assoc_state<_Rp>
925{
926    typedef __assoc_state<_Rp> base;
927
928    _Fp __func_;
929
930    virtual void __on_zero_shared() _NOEXCEPT;
931public:
932    _LIBCPP_INLINE_VISIBILITY
933    explicit __async_assoc_state(_Fp&& __f);
934
935    virtual void __execute();
936};
937
938template <class _Rp, class _Fp>
939inline
940__async_assoc_state<_Rp, _Fp>::__async_assoc_state(_Fp&& __f)
941    : __func_(_VSTD::forward<_Fp>(__f))
942{
943}
944
945template <class _Rp, class _Fp>
946void
947__async_assoc_state<_Rp, _Fp>::__execute()
948{
949#ifndef _LIBCPP_NO_EXCEPTIONS
950    try
951    {
952#endif // _LIBCPP_NO_EXCEPTIONS
953        this->set_value(__func_());
954#ifndef _LIBCPP_NO_EXCEPTIONS
955    }
956    catch (...)
957    {
958        this->set_exception(current_exception());
959    }
960#endif // _LIBCPP_NO_EXCEPTIONS
961}
962
963template <class _Rp, class _Fp>
964void
965__async_assoc_state<_Rp, _Fp>::__on_zero_shared() _NOEXCEPT
966{
967    this->wait();
968    base::__on_zero_shared();
969}
970
971template <class _Fp>
972class _LIBCPP_AVAILABILITY_FUTURE __async_assoc_state<void, _Fp>
973    : public __assoc_sub_state
974{
975    typedef __assoc_sub_state base;
976
977    _Fp __func_;
978
979    virtual void __on_zero_shared() _NOEXCEPT;
980public:
981    _LIBCPP_INLINE_VISIBILITY
982    explicit __async_assoc_state(_Fp&& __f);
983
984    virtual void __execute();
985};
986
987template <class _Fp>
988inline
989__async_assoc_state<void, _Fp>::__async_assoc_state(_Fp&& __f)
990    : __func_(_VSTD::forward<_Fp>(__f))
991{
992}
993
994template <class _Fp>
995void
996__async_assoc_state<void, _Fp>::__execute()
997{
998#ifndef _LIBCPP_NO_EXCEPTIONS
999    try
1000    {
1001#endif // _LIBCPP_NO_EXCEPTIONS
1002        __func_();
1003        this->set_value();
1004#ifndef _LIBCPP_NO_EXCEPTIONS
1005    }
1006    catch (...)
1007    {
1008        this->set_exception(current_exception());
1009    }
1010#endif // _LIBCPP_NO_EXCEPTIONS
1011}
1012
1013template <class _Fp>
1014void
1015__async_assoc_state<void, _Fp>::__on_zero_shared() _NOEXCEPT
1016{
1017    this->wait();
1018    base::__on_zero_shared();
1019}
1020
1021template <class _Rp> class _LIBCPP_TEMPLATE_VIS promise;
1022template <class _Rp> class _LIBCPP_TEMPLATE_VIS shared_future;
1023
1024// future
1025
1026template <class _Rp> class _LIBCPP_TEMPLATE_VIS future;
1027
1028template <class _Rp, class _Fp>
1029_LIBCPP_INLINE_VISIBILITY future<_Rp>
1030__make_deferred_assoc_state(_Fp&& __f);
1031
1032template <class _Rp, class _Fp>
1033_LIBCPP_INLINE_VISIBILITY future<_Rp>
1034__make_async_assoc_state(_Fp&& __f);
1035
1036template <class _Rp>
1037class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE future
1038{
1039    __assoc_state<_Rp>* __state_;
1040
1041    explicit future(__assoc_state<_Rp>* __state);
1042
1043    template <class> friend class promise;
1044    template <class> friend class shared_future;
1045
1046    template <class _R1, class _Fp>
1047        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
1048    template <class _R1, class _Fp>
1049        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
1050
1051public:
1052    _LIBCPP_INLINE_VISIBILITY
1053    future() _NOEXCEPT : __state_(nullptr) {}
1054    _LIBCPP_INLINE_VISIBILITY
1055    future(future&& __rhs) _NOEXCEPT
1056        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1057    future(const future&) = delete;
1058    future& operator=(const future&) = delete;
1059    _LIBCPP_INLINE_VISIBILITY
1060    future& operator=(future&& __rhs) _NOEXCEPT
1061        {
1062            future(_VSTD::move(__rhs)).swap(*this);
1063            return *this;
1064        }
1065
1066    ~future();
1067    _LIBCPP_INLINE_VISIBILITY
1068    shared_future<_Rp> share() _NOEXCEPT;
1069
1070    // retrieving the value
1071    _Rp get();
1072
1073    _LIBCPP_INLINE_VISIBILITY
1074    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1075
1076    // functions to check state
1077    _LIBCPP_INLINE_VISIBILITY
1078    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
1079
1080    _LIBCPP_INLINE_VISIBILITY
1081    void wait() const {__state_->wait();}
1082    template <class _Rep, class _Period>
1083        _LIBCPP_INLINE_VISIBILITY
1084        future_status
1085        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
1086            {return __state_->wait_for(__rel_time);}
1087    template <class _Clock, class _Duration>
1088        _LIBCPP_INLINE_VISIBILITY
1089        future_status
1090        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
1091            {return __state_->wait_until(__abs_time);}
1092};
1093
1094template <class _Rp>
1095future<_Rp>::future(__assoc_state<_Rp>* __state)
1096    : __state_(__state)
1097{
1098    __state_->__attach_future();
1099}
1100
1101struct __release_shared_count
1102{
1103    void operator()(__shared_count* p) {p->__release_shared();}
1104};
1105
1106template <class _Rp>
1107future<_Rp>::~future()
1108{
1109    if (__state_)
1110        __state_->__release_shared();
1111}
1112
1113template <class _Rp>
1114_Rp
1115future<_Rp>::get()
1116{
1117    unique_ptr<__shared_count, __release_shared_count> __(__state_);
1118    __assoc_state<_Rp>* __s = __state_;
1119    __state_ = nullptr;
1120    return __s->move();
1121}
1122
1123template <class _Rp>
1124class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE future<_Rp&>
1125{
1126    __assoc_state<_Rp&>* __state_;
1127
1128    explicit future(__assoc_state<_Rp&>* __state);
1129
1130    template <class> friend class promise;
1131    template <class> friend class shared_future;
1132
1133    template <class _R1, class _Fp>
1134        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
1135    template <class _R1, class _Fp>
1136        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
1137
1138public:
1139    _LIBCPP_INLINE_VISIBILITY
1140    future() _NOEXCEPT : __state_(nullptr) {}
1141    _LIBCPP_INLINE_VISIBILITY
1142    future(future&& __rhs) _NOEXCEPT
1143        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1144    future(const future&) = delete;
1145    future& operator=(const future&) = delete;
1146    _LIBCPP_INLINE_VISIBILITY
1147    future& operator=(future&& __rhs) _NOEXCEPT
1148        {
1149            future(_VSTD::move(__rhs)).swap(*this);
1150            return *this;
1151        }
1152
1153    ~future();
1154    _LIBCPP_INLINE_VISIBILITY
1155    shared_future<_Rp&> share() _NOEXCEPT;
1156
1157    // retrieving the value
1158    _Rp& get();
1159
1160    _LIBCPP_INLINE_VISIBILITY
1161    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1162
1163    // functions to check state
1164    _LIBCPP_INLINE_VISIBILITY
1165    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
1166
1167    _LIBCPP_INLINE_VISIBILITY
1168    void wait() const {__state_->wait();}
1169    template <class _Rep, class _Period>
1170        _LIBCPP_INLINE_VISIBILITY
1171        future_status
1172        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
1173            {return __state_->wait_for(__rel_time);}
1174    template <class _Clock, class _Duration>
1175        _LIBCPP_INLINE_VISIBILITY
1176        future_status
1177        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
1178            {return __state_->wait_until(__abs_time);}
1179};
1180
1181template <class _Rp>
1182future<_Rp&>::future(__assoc_state<_Rp&>* __state)
1183    : __state_(__state)
1184{
1185    __state_->__attach_future();
1186}
1187
1188template <class _Rp>
1189future<_Rp&>::~future()
1190{
1191    if (__state_)
1192        __state_->__release_shared();
1193}
1194
1195template <class _Rp>
1196_Rp&
1197future<_Rp&>::get()
1198{
1199    unique_ptr<__shared_count, __release_shared_count> __(__state_);
1200    __assoc_state<_Rp&>* __s = __state_;
1201    __state_ = nullptr;
1202    return __s->copy();
1203}
1204
1205template <>
1206class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE future<void>
1207{
1208    __assoc_sub_state* __state_;
1209
1210    explicit future(__assoc_sub_state* __state);
1211
1212    template <class> friend class promise;
1213    template <class> friend class shared_future;
1214
1215    template <class _R1, class _Fp>
1216        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
1217    template <class _R1, class _Fp>
1218        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
1219
1220public:
1221    _LIBCPP_INLINE_VISIBILITY
1222    future() _NOEXCEPT : __state_(nullptr) {}
1223    _LIBCPP_INLINE_VISIBILITY
1224    future(future&& __rhs) _NOEXCEPT
1225        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1226    future(const future&) = delete;
1227    future& operator=(const future&) = delete;
1228    _LIBCPP_INLINE_VISIBILITY
1229    future& operator=(future&& __rhs) _NOEXCEPT
1230        {
1231            future(_VSTD::move(__rhs)).swap(*this);
1232            return *this;
1233        }
1234
1235    ~future();
1236    _LIBCPP_INLINE_VISIBILITY
1237    shared_future<void> share() _NOEXCEPT;
1238
1239    // retrieving the value
1240    void get();
1241
1242    _LIBCPP_INLINE_VISIBILITY
1243    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1244
1245    // functions to check state
1246    _LIBCPP_INLINE_VISIBILITY
1247    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
1248
1249    _LIBCPP_INLINE_VISIBILITY
1250    void wait() const {__state_->wait();}
1251    template <class _Rep, class _Period>
1252        _LIBCPP_INLINE_VISIBILITY
1253        future_status
1254        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
1255            {return __state_->wait_for(__rel_time);}
1256    template <class _Clock, class _Duration>
1257        _LIBCPP_INLINE_VISIBILITY
1258        future_status
1259        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
1260            {return __state_->wait_until(__abs_time);}
1261};
1262
1263template <class _Rp>
1264inline _LIBCPP_INLINE_VISIBILITY
1265void
1266swap(future<_Rp>& __x, future<_Rp>& __y) _NOEXCEPT
1267{
1268    __x.swap(__y);
1269}
1270
1271// promise<R>
1272
1273template <class _Callable> class packaged_task;
1274
1275template <class _Rp>
1276class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE promise
1277{
1278    __assoc_state<_Rp>* __state_;
1279
1280    _LIBCPP_INLINE_VISIBILITY
1281    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
1282
1283    template <class> friend class packaged_task;
1284public:
1285    promise();
1286    template <class _Alloc>
1287        promise(allocator_arg_t, const _Alloc& __a);
1288    _LIBCPP_INLINE_VISIBILITY
1289    promise(promise&& __rhs) _NOEXCEPT
1290        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1291    promise(const promise& __rhs) = delete;
1292    ~promise();
1293
1294    // assignment
1295    _LIBCPP_INLINE_VISIBILITY
1296    promise& operator=(promise&& __rhs) _NOEXCEPT
1297        {
1298            promise(_VSTD::move(__rhs)).swap(*this);
1299            return *this;
1300        }
1301    promise& operator=(const promise& __rhs) = delete;
1302
1303    _LIBCPP_INLINE_VISIBILITY
1304    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1305
1306    // retrieving the result
1307    future<_Rp> get_future();
1308
1309    // setting the result
1310    void set_value(const _Rp& __r);
1311    void set_value(_Rp&& __r);
1312    void set_exception(exception_ptr __p);
1313
1314    // setting the result with deferred notification
1315    void set_value_at_thread_exit(const _Rp& __r);
1316    void set_value_at_thread_exit(_Rp&& __r);
1317    void set_exception_at_thread_exit(exception_ptr __p);
1318};
1319
1320template <class _Rp>
1321promise<_Rp>::promise()
1322    : __state_(new __assoc_state<_Rp>)
1323{
1324}
1325
1326template <class _Rp>
1327template <class _Alloc>
1328promise<_Rp>::promise(allocator_arg_t, const _Alloc& __a0)
1329{
1330    typedef __assoc_state_alloc<_Rp, _Alloc> _State;
1331    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
1332    typedef __allocator_destructor<_A2> _D2;
1333    _A2 __a(__a0);
1334    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
1335    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
1336    __state_ = _VSTD::addressof(*__hold.release());
1337}
1338
1339template <class _Rp>
1340promise<_Rp>::~promise()
1341{
1342    if (__state_)
1343    {
1344        if (!__state_->__has_value() && __state_->use_count() > 1)
1345            __state_->set_exception(make_exception_ptr(
1346                      future_error(make_error_code(future_errc::broken_promise))
1347                                                      ));
1348        __state_->__release_shared();
1349    }
1350}
1351
1352template <class _Rp>
1353future<_Rp>
1354promise<_Rp>::get_future()
1355{
1356    if (__state_ == nullptr)
1357        __throw_future_error(future_errc::no_state);
1358    return future<_Rp>(__state_);
1359}
1360
1361template <class _Rp>
1362void
1363promise<_Rp>::set_value(const _Rp& __r)
1364{
1365    if (__state_ == nullptr)
1366        __throw_future_error(future_errc::no_state);
1367    __state_->set_value(__r);
1368}
1369
1370template <class _Rp>
1371void
1372promise<_Rp>::set_value(_Rp&& __r)
1373{
1374    if (__state_ == nullptr)
1375        __throw_future_error(future_errc::no_state);
1376    __state_->set_value(_VSTD::move(__r));
1377}
1378
1379template <class _Rp>
1380void
1381promise<_Rp>::set_exception(exception_ptr __p)
1382{
1383    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception: received nullptr" );
1384    if (__state_ == nullptr)
1385        __throw_future_error(future_errc::no_state);
1386    __state_->set_exception(__p);
1387}
1388
1389template <class _Rp>
1390void
1391promise<_Rp>::set_value_at_thread_exit(const _Rp& __r)
1392{
1393    if (__state_ == nullptr)
1394        __throw_future_error(future_errc::no_state);
1395    __state_->set_value_at_thread_exit(__r);
1396}
1397
1398template <class _Rp>
1399void
1400promise<_Rp>::set_value_at_thread_exit(_Rp&& __r)
1401{
1402    if (__state_ == nullptr)
1403        __throw_future_error(future_errc::no_state);
1404    __state_->set_value_at_thread_exit(_VSTD::move(__r));
1405}
1406
1407template <class _Rp>
1408void
1409promise<_Rp>::set_exception_at_thread_exit(exception_ptr __p)
1410{
1411    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception_at_thread_exit: received nullptr" );
1412    if (__state_ == nullptr)
1413        __throw_future_error(future_errc::no_state);
1414    __state_->set_exception_at_thread_exit(__p);
1415}
1416
1417// promise<R&>
1418
1419template <class _Rp>
1420class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE promise<_Rp&>
1421{
1422    __assoc_state<_Rp&>* __state_;
1423
1424    _LIBCPP_INLINE_VISIBILITY
1425    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
1426
1427    template <class> friend class packaged_task;
1428
1429public:
1430    promise();
1431    template <class _Allocator>
1432        promise(allocator_arg_t, const _Allocator& __a);
1433    _LIBCPP_INLINE_VISIBILITY
1434    promise(promise&& __rhs) _NOEXCEPT
1435        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1436    promise(const promise& __rhs) = delete;
1437    ~promise();
1438
1439    // assignment
1440    _LIBCPP_INLINE_VISIBILITY
1441    promise& operator=(promise&& __rhs) _NOEXCEPT
1442        {
1443            promise(_VSTD::move(__rhs)).swap(*this);
1444            return *this;
1445        }
1446    promise& operator=(const promise& __rhs) = delete;
1447
1448    _LIBCPP_INLINE_VISIBILITY
1449    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1450
1451    // retrieving the result
1452    future<_Rp&> get_future();
1453
1454    // setting the result
1455    void set_value(_Rp& __r);
1456    void set_exception(exception_ptr __p);
1457
1458    // setting the result with deferred notification
1459    void set_value_at_thread_exit(_Rp&);
1460    void set_exception_at_thread_exit(exception_ptr __p);
1461};
1462
1463template <class _Rp>
1464promise<_Rp&>::promise()
1465    : __state_(new __assoc_state<_Rp&>)
1466{
1467}
1468
1469template <class _Rp>
1470template <class _Alloc>
1471promise<_Rp&>::promise(allocator_arg_t, const _Alloc& __a0)
1472{
1473    typedef __assoc_state_alloc<_Rp&, _Alloc> _State;
1474    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
1475    typedef __allocator_destructor<_A2> _D2;
1476    _A2 __a(__a0);
1477    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
1478    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
1479    __state_ = _VSTD::addressof(*__hold.release());
1480}
1481
1482template <class _Rp>
1483promise<_Rp&>::~promise()
1484{
1485    if (__state_)
1486    {
1487        if (!__state_->__has_value() && __state_->use_count() > 1)
1488            __state_->set_exception(make_exception_ptr(
1489                      future_error(make_error_code(future_errc::broken_promise))
1490                                                      ));
1491        __state_->__release_shared();
1492    }
1493}
1494
1495template <class _Rp>
1496future<_Rp&>
1497promise<_Rp&>::get_future()
1498{
1499    if (__state_ == nullptr)
1500        __throw_future_error(future_errc::no_state);
1501    return future<_Rp&>(__state_);
1502}
1503
1504template <class _Rp>
1505void
1506promise<_Rp&>::set_value(_Rp& __r)
1507{
1508    if (__state_ == nullptr)
1509        __throw_future_error(future_errc::no_state);
1510    __state_->set_value(__r);
1511}
1512
1513template <class _Rp>
1514void
1515promise<_Rp&>::set_exception(exception_ptr __p)
1516{
1517    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception: received nullptr" );
1518    if (__state_ == nullptr)
1519        __throw_future_error(future_errc::no_state);
1520    __state_->set_exception(__p);
1521}
1522
1523template <class _Rp>
1524void
1525promise<_Rp&>::set_value_at_thread_exit(_Rp& __r)
1526{
1527    if (__state_ == nullptr)
1528        __throw_future_error(future_errc::no_state);
1529    __state_->set_value_at_thread_exit(__r);
1530}
1531
1532template <class _Rp>
1533void
1534promise<_Rp&>::set_exception_at_thread_exit(exception_ptr __p)
1535{
1536    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception_at_thread_exit: received nullptr" );
1537    if (__state_ == nullptr)
1538        __throw_future_error(future_errc::no_state);
1539    __state_->set_exception_at_thread_exit(__p);
1540}
1541
1542// promise<void>
1543
1544template <>
1545class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE promise<void>
1546{
1547    __assoc_sub_state* __state_;
1548
1549    _LIBCPP_INLINE_VISIBILITY
1550    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
1551
1552    template <class> friend class packaged_task;
1553
1554public:
1555    promise();
1556    template <class _Allocator>
1557        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
1558        promise(allocator_arg_t, const _Allocator& __a);
1559    _LIBCPP_INLINE_VISIBILITY
1560    promise(promise&& __rhs) _NOEXCEPT
1561        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
1562    promise(const promise& __rhs) = delete;
1563    ~promise();
1564
1565    // assignment
1566    _LIBCPP_INLINE_VISIBILITY
1567    promise& operator=(promise&& __rhs) _NOEXCEPT
1568        {
1569            promise(_VSTD::move(__rhs)).swap(*this);
1570            return *this;
1571        }
1572    promise& operator=(const promise& __rhs) = delete;
1573
1574    _LIBCPP_INLINE_VISIBILITY
1575    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
1576
1577    // retrieving the result
1578    future<void> get_future();
1579
1580    // setting the result
1581    void set_value();
1582    void set_exception(exception_ptr __p);
1583
1584    // setting the result with deferred notification
1585    void set_value_at_thread_exit();
1586    void set_exception_at_thread_exit(exception_ptr __p);
1587};
1588
1589template <class _Alloc>
1590promise<void>::promise(allocator_arg_t, const _Alloc& __a0)
1591{
1592    typedef __assoc_sub_state_alloc<_Alloc> _State;
1593    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
1594    typedef __allocator_destructor<_A2> _D2;
1595    _A2 __a(__a0);
1596    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
1597    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
1598    __state_ = _VSTD::addressof(*__hold.release());
1599}
1600
1601template <class _Rp>
1602inline _LIBCPP_INLINE_VISIBILITY
1603void
1604swap(promise<_Rp>& __x, promise<_Rp>& __y) _NOEXCEPT
1605{
1606    __x.swap(__y);
1607}
1608
1609template <class _Rp, class _Alloc>
1610    struct _LIBCPP_TEMPLATE_VIS uses_allocator<promise<_Rp>, _Alloc>
1611        : public true_type {};
1612
1613// packaged_task
1614
1615template<class _Fp> class __packaged_task_base;
1616
1617template<class _Rp, class ..._ArgTypes>
1618class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_base<_Rp(_ArgTypes...)>
1619{
1620    __packaged_task_base(const __packaged_task_base&);
1621    __packaged_task_base& operator=(const __packaged_task_base&);
1622public:
1623    _LIBCPP_INLINE_VISIBILITY
1624    __packaged_task_base() {}
1625    _LIBCPP_INLINE_VISIBILITY
1626    virtual ~__packaged_task_base() {}
1627    virtual void __move_to(__packaged_task_base*) _NOEXCEPT = 0;
1628    virtual void destroy() = 0;
1629    virtual void destroy_deallocate() = 0;
1630    virtual _Rp operator()(_ArgTypes&& ...) = 0;
1631};
1632
1633template<class _FD, class _Alloc, class _FB> class __packaged_task_func;
1634
1635template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1636class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>
1637    : public  __packaged_task_base<_Rp(_ArgTypes...)>
1638{
1639    __compressed_pair<_Fp, _Alloc> __f_;
1640public:
1641    _LIBCPP_INLINE_VISIBILITY
1642    explicit __packaged_task_func(const _Fp& __f) : __f_(__f, __default_init_tag()) {}
1643    _LIBCPP_INLINE_VISIBILITY
1644    explicit __packaged_task_func(_Fp&& __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
1645    _LIBCPP_INLINE_VISIBILITY
1646    __packaged_task_func(const _Fp& __f, const _Alloc& __a)
1647        : __f_(__f, __a) {}
1648    _LIBCPP_INLINE_VISIBILITY
1649    __packaged_task_func(_Fp&& __f, const _Alloc& __a)
1650        : __f_(_VSTD::move(__f), __a) {}
1651    virtual void __move_to(__packaged_task_base<_Rp(_ArgTypes...)>*) _NOEXCEPT;
1652    virtual void destroy();
1653    virtual void destroy_deallocate();
1654    virtual _Rp operator()(_ArgTypes&& ... __args);
1655};
1656
1657template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1658void
1659__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__move_to(
1660                              __packaged_task_base<_Rp(_ArgTypes...)>* __p) _NOEXCEPT
1661{
1662    ::new ((void*)__p) __packaged_task_func(_VSTD::move(__f_.first()), _VSTD::move(__f_.second()));
1663}
1664
1665template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1666void
1667__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy()
1668{
1669    __f_.~__compressed_pair<_Fp, _Alloc>();
1670}
1671
1672template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1673void
1674__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate()
1675{
1676    typedef typename __allocator_traits_rebind<_Alloc, __packaged_task_func>::type _Ap;
1677    typedef allocator_traits<_Ap> _ATraits;
1678    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
1679    _Ap __a(__f_.second());
1680    __f_.~__compressed_pair<_Fp, _Alloc>();
1681    __a.deallocate(_PTraits::pointer_to(*this), 1);
1682}
1683
1684template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
1685_Rp
1686__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&& ... __arg)
1687{
1688    return _VSTD::__invoke(__f_.first(), _VSTD::forward<_ArgTypes>(__arg)...);
1689}
1690
1691template <class _Callable> class __packaged_task_function;
1692
1693template<class _Rp, class ..._ArgTypes>
1694class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_function<_Rp(_ArgTypes...)>
1695{
1696    typedef __packaged_task_base<_Rp(_ArgTypes...)> __base;
1697
1698    _LIBCPP_INLINE_VISIBILITY _LIBCPP_NO_CFI
1699    __base* __get_buf() { return (__base*)&__buf_; }
1700
1701    typename aligned_storage<3*sizeof(void*)>::type __buf_;
1702    __base* __f_;
1703
1704public:
1705    typedef _Rp result_type;
1706
1707    // construct/copy/destroy:
1708    _LIBCPP_INLINE_VISIBILITY
1709    __packaged_task_function() _NOEXCEPT : __f_(nullptr) {}
1710    template<class _Fp>
1711      __packaged_task_function(_Fp&& __f);
1712    template<class _Fp, class _Alloc>
1713      __packaged_task_function(allocator_arg_t, const _Alloc& __a, _Fp&& __f);
1714
1715    __packaged_task_function(__packaged_task_function&&) _NOEXCEPT;
1716    __packaged_task_function& operator=(__packaged_task_function&&) _NOEXCEPT;
1717
1718    __packaged_task_function(const __packaged_task_function&) =  delete;
1719    __packaged_task_function& operator=(const __packaged_task_function&) =  delete;
1720
1721    ~__packaged_task_function();
1722
1723    void swap(__packaged_task_function&) _NOEXCEPT;
1724
1725    _LIBCPP_INLINE_VISIBILITY
1726    _Rp operator()(_ArgTypes...) const;
1727};
1728
1729template<class _Rp, class ..._ArgTypes>
1730__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(__packaged_task_function&& __f) _NOEXCEPT
1731{
1732    if (__f.__f_ == nullptr)
1733        __f_ = nullptr;
1734    else if (__f.__f_ == __f.__get_buf())
1735    {
1736        __f.__f_->__move_to(__get_buf());
1737        __f_ = (__base*)&__buf_;
1738    }
1739    else
1740    {
1741        __f_ = __f.__f_;
1742        __f.__f_ = nullptr;
1743    }
1744}
1745
1746template<class _Rp, class ..._ArgTypes>
1747template <class _Fp>
1748__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(_Fp&& __f)
1749    : __f_(nullptr)
1750{
1751    typedef typename remove_reference<typename decay<_Fp>::type>::type _FR;
1752    typedef __packaged_task_func<_FR, allocator<_FR>, _Rp(_ArgTypes...)> _FF;
1753    if (sizeof(_FF) <= sizeof(__buf_))
1754    {
1755        ::new ((void*)&__buf_) _FF(_VSTD::forward<_Fp>(__f));
1756        __f_ = (__base*)&__buf_;
1757    }
1758    else
1759    {
1760        typedef allocator<_FF> _Ap;
1761        _Ap __a;
1762        typedef __allocator_destructor<_Ap> _Dp;
1763        unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
1764        ::new ((void*)__hold.get()) _FF(_VSTD::forward<_Fp>(__f), allocator<_FR>(__a));
1765        __f_ = __hold.release();
1766    }
1767}
1768
1769template<class _Rp, class ..._ArgTypes>
1770template <class _Fp, class _Alloc>
1771__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(
1772                                  allocator_arg_t, const _Alloc& __a0, _Fp&& __f)
1773    : __f_(nullptr)
1774{
1775    typedef typename remove_reference<typename decay<_Fp>::type>::type _FR;
1776    typedef __packaged_task_func<_FR, _Alloc, _Rp(_ArgTypes...)> _FF;
1777    if (sizeof(_FF) <= sizeof(__buf_))
1778    {
1779        __f_ = (__base*)&__buf_;
1780        ::new ((void*)__f_) _FF(_VSTD::forward<_Fp>(__f));
1781    }
1782    else
1783    {
1784        typedef typename __allocator_traits_rebind<_Alloc, _FF>::type _Ap;
1785        _Ap __a(__a0);
1786        typedef __allocator_destructor<_Ap> _Dp;
1787        unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
1788        ::new ((void*)_VSTD::addressof(*__hold.get()))
1789            _FF(_VSTD::forward<_Fp>(__f), _Alloc(__a));
1790        __f_ = _VSTD::addressof(*__hold.release());
1791    }
1792}
1793
1794template<class _Rp, class ..._ArgTypes>
1795__packaged_task_function<_Rp(_ArgTypes...)>&
1796__packaged_task_function<_Rp(_ArgTypes...)>::operator=(__packaged_task_function&& __f) _NOEXCEPT
1797{
1798    if (__f_ == __get_buf())
1799        __f_->destroy();
1800    else if (__f_)
1801        __f_->destroy_deallocate();
1802    __f_ = nullptr;
1803    if (__f.__f_ == nullptr)
1804        __f_ = nullptr;
1805    else if (__f.__f_ == __f.__get_buf())
1806    {
1807        __f.__f_->__move_to(__get_buf());
1808        __f_ = __get_buf();
1809    }
1810    else
1811    {
1812        __f_ = __f.__f_;
1813        __f.__f_ = nullptr;
1814    }
1815    return *this;
1816}
1817
1818template<class _Rp, class ..._ArgTypes>
1819__packaged_task_function<_Rp(_ArgTypes...)>::~__packaged_task_function()
1820{
1821    if (__f_ == __get_buf())
1822        __f_->destroy();
1823    else if (__f_)
1824        __f_->destroy_deallocate();
1825}
1826
1827template<class _Rp, class ..._ArgTypes>
1828_LIBCPP_NO_CFI
1829void
1830__packaged_task_function<_Rp(_ArgTypes...)>::swap(__packaged_task_function& __f) _NOEXCEPT
1831{
1832    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
1833    {
1834        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
1835        __base* __t = (__base*)&__tempbuf;
1836        __f_->__move_to(__t);
1837        __f_->destroy();
1838        __f_ = nullptr;
1839        __f.__f_->__move_to((__base*)&__buf_);
1840        __f.__f_->destroy();
1841        __f.__f_ = nullptr;
1842        __f_ = (__base*)&__buf_;
1843        __t->__move_to((__base*)&__f.__buf_);
1844        __t->destroy();
1845        __f.__f_ = (__base*)&__f.__buf_;
1846    }
1847    else if (__f_ == (__base*)&__buf_)
1848    {
1849        __f_->__move_to((__base*)&__f.__buf_);
1850        __f_->destroy();
1851        __f_ = __f.__f_;
1852        __f.__f_ = (__base*)&__f.__buf_;
1853    }
1854    else if (__f.__f_ == (__base*)&__f.__buf_)
1855    {
1856        __f.__f_->__move_to((__base*)&__buf_);
1857        __f.__f_->destroy();
1858        __f.__f_ = __f_;
1859        __f_ = (__base*)&__buf_;
1860    }
1861    else
1862        _VSTD::swap(__f_, __f.__f_);
1863}
1864
1865template<class _Rp, class ..._ArgTypes>
1866inline
1867_Rp
1868__packaged_task_function<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __arg) const
1869{
1870    return (*__f_)(_VSTD::forward<_ArgTypes>(__arg)...);
1871}
1872
1873template<class _Rp, class ..._ArgTypes>
1874class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE packaged_task<_Rp(_ArgTypes...)>
1875{
1876public:
1877    typedef _Rp result_type; // extension
1878
1879private:
1880    __packaged_task_function<result_type(_ArgTypes...)> __f_;
1881    promise<result_type>                                __p_;
1882
1883public:
1884    // construction and destruction
1885    _LIBCPP_INLINE_VISIBILITY
1886    packaged_task() _NOEXCEPT : __p_(nullptr) {}
1887    template <class _Fp,
1888              class = typename enable_if
1889              <
1890                  !is_same<
1891                      typename __uncvref<_Fp>::type,
1892                      packaged_task
1893                      >::value
1894                  >::type
1895             >
1896        _LIBCPP_INLINE_VISIBILITY
1897        explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
1898    template <class _Fp, class _Allocator,
1899              class = typename enable_if
1900              <
1901                  !is_same<
1902                      typename __uncvref<_Fp>::type,
1903                      packaged_task
1904                      >::value
1905                  >::type
1906              >
1907        _LIBCPP_INLINE_VISIBILITY
1908        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
1909             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
1910               __p_(allocator_arg, __a) {}
1911    // ~packaged_task() = default;
1912
1913    // no copy
1914    packaged_task(const packaged_task&) = delete;
1915    packaged_task& operator=(const packaged_task&) = delete;
1916
1917    // move support
1918    _LIBCPP_INLINE_VISIBILITY
1919    packaged_task(packaged_task&& __other) _NOEXCEPT
1920        : __f_(_VSTD::move(__other.__f_)), __p_(_VSTD::move(__other.__p_)) {}
1921    _LIBCPP_INLINE_VISIBILITY
1922    packaged_task& operator=(packaged_task&& __other) _NOEXCEPT
1923    {
1924        __f_ = _VSTD::move(__other.__f_);
1925        __p_ = _VSTD::move(__other.__p_);
1926        return *this;
1927    }
1928    _LIBCPP_INLINE_VISIBILITY
1929    void swap(packaged_task& __other) _NOEXCEPT
1930    {
1931        __f_.swap(__other.__f_);
1932        __p_.swap(__other.__p_);
1933    }
1934
1935    _LIBCPP_INLINE_VISIBILITY
1936    bool valid() const _NOEXCEPT {return __p_.__state_ != nullptr;}
1937
1938    // result retrieval
1939    _LIBCPP_INLINE_VISIBILITY
1940    future<result_type> get_future() {return __p_.get_future();}
1941
1942    // execution
1943    void operator()(_ArgTypes... __args);
1944    void make_ready_at_thread_exit(_ArgTypes... __args);
1945
1946    void reset();
1947};
1948
1949template<class _Rp, class ..._ArgTypes>
1950void
1951packaged_task<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __args)
1952{
1953    if (__p_.__state_ == nullptr)
1954        __throw_future_error(future_errc::no_state);
1955    if (__p_.__state_->__has_value())
1956        __throw_future_error(future_errc::promise_already_satisfied);
1957#ifndef _LIBCPP_NO_EXCEPTIONS
1958    try
1959    {
1960#endif // _LIBCPP_NO_EXCEPTIONS
1961        __p_.set_value(__f_(_VSTD::forward<_ArgTypes>(__args)...));
1962#ifndef _LIBCPP_NO_EXCEPTIONS
1963    }
1964    catch (...)
1965    {
1966        __p_.set_exception(current_exception());
1967    }
1968#endif // _LIBCPP_NO_EXCEPTIONS
1969}
1970
1971template<class _Rp, class ..._ArgTypes>
1972void
1973packaged_task<_Rp(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args)
1974{
1975    if (__p_.__state_ == nullptr)
1976        __throw_future_error(future_errc::no_state);
1977    if (__p_.__state_->__has_value())
1978        __throw_future_error(future_errc::promise_already_satisfied);
1979#ifndef _LIBCPP_NO_EXCEPTIONS
1980    try
1981    {
1982#endif // _LIBCPP_NO_EXCEPTIONS
1983        __p_.set_value_at_thread_exit(__f_(_VSTD::forward<_ArgTypes>(__args)...));
1984#ifndef _LIBCPP_NO_EXCEPTIONS
1985    }
1986    catch (...)
1987    {
1988        __p_.set_exception_at_thread_exit(current_exception());
1989    }
1990#endif // _LIBCPP_NO_EXCEPTIONS
1991}
1992
1993template<class _Rp, class ..._ArgTypes>
1994void
1995packaged_task<_Rp(_ArgTypes...)>::reset()
1996{
1997    if (!valid())
1998        __throw_future_error(future_errc::no_state);
1999    __p_ = promise<result_type>();
2000}
2001
2002template<class ..._ArgTypes>
2003class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE packaged_task<void(_ArgTypes...)>
2004{
2005public:
2006    typedef void result_type; // extension
2007
2008private:
2009    __packaged_task_function<result_type(_ArgTypes...)> __f_;
2010    promise<result_type>                                __p_;
2011
2012public:
2013    // construction and destruction
2014    _LIBCPP_INLINE_VISIBILITY
2015    packaged_task() _NOEXCEPT : __p_(nullptr) {}
2016    template <class _Fp,
2017              class = typename enable_if
2018              <
2019                  !is_same<
2020                      typename __uncvref<_Fp>::type,
2021                      packaged_task
2022                      >::value
2023                  >::type
2024              >
2025        _LIBCPP_INLINE_VISIBILITY
2026        explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
2027    template <class _Fp, class _Allocator,
2028              class = typename enable_if
2029              <
2030                  !is_same<
2031                      typename __uncvref<_Fp>::type,
2032                      packaged_task
2033                      >::value
2034                  >::type
2035              >
2036        _LIBCPP_INLINE_VISIBILITY
2037        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
2038             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
2039               __p_(allocator_arg, __a) {}
2040    // ~packaged_task() = default;
2041
2042    // no copy
2043    packaged_task(const packaged_task&) = delete;
2044    packaged_task& operator=(const packaged_task&) = delete;
2045
2046    // move support
2047    _LIBCPP_INLINE_VISIBILITY
2048    packaged_task(packaged_task&& __other) _NOEXCEPT
2049        : __f_(_VSTD::move(__other.__f_)), __p_(_VSTD::move(__other.__p_)) {}
2050    _LIBCPP_INLINE_VISIBILITY
2051    packaged_task& operator=(packaged_task&& __other) _NOEXCEPT
2052    {
2053        __f_ = _VSTD::move(__other.__f_);
2054        __p_ = _VSTD::move(__other.__p_);
2055        return *this;
2056    }
2057    _LIBCPP_INLINE_VISIBILITY
2058    void swap(packaged_task& __other) _NOEXCEPT
2059    {
2060        __f_.swap(__other.__f_);
2061        __p_.swap(__other.__p_);
2062    }
2063
2064    _LIBCPP_INLINE_VISIBILITY
2065    bool valid() const _NOEXCEPT {return __p_.__state_ != nullptr;}
2066
2067    // result retrieval
2068    _LIBCPP_INLINE_VISIBILITY
2069    future<result_type> get_future() {return __p_.get_future();}
2070
2071    // execution
2072    void operator()(_ArgTypes... __args);
2073    void make_ready_at_thread_exit(_ArgTypes... __args);
2074
2075    void reset();
2076};
2077
2078template<class ..._ArgTypes>
2079void
2080packaged_task<void(_ArgTypes...)>::operator()(_ArgTypes... __args)
2081{
2082    if (__p_.__state_ == nullptr)
2083        __throw_future_error(future_errc::no_state);
2084    if (__p_.__state_->__has_value())
2085        __throw_future_error(future_errc::promise_already_satisfied);
2086#ifndef _LIBCPP_NO_EXCEPTIONS
2087    try
2088    {
2089#endif // _LIBCPP_NO_EXCEPTIONS
2090        __f_(_VSTD::forward<_ArgTypes>(__args)...);
2091        __p_.set_value();
2092#ifndef _LIBCPP_NO_EXCEPTIONS
2093    }
2094    catch (...)
2095    {
2096        __p_.set_exception(current_exception());
2097    }
2098#endif // _LIBCPP_NO_EXCEPTIONS
2099}
2100
2101template<class ..._ArgTypes>
2102void
2103packaged_task<void(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args)
2104{
2105    if (__p_.__state_ == nullptr)
2106        __throw_future_error(future_errc::no_state);
2107    if (__p_.__state_->__has_value())
2108        __throw_future_error(future_errc::promise_already_satisfied);
2109#ifndef _LIBCPP_NO_EXCEPTIONS
2110    try
2111    {
2112#endif // _LIBCPP_NO_EXCEPTIONS
2113        __f_(_VSTD::forward<_ArgTypes>(__args)...);
2114        __p_.set_value_at_thread_exit();
2115#ifndef _LIBCPP_NO_EXCEPTIONS
2116    }
2117    catch (...)
2118    {
2119        __p_.set_exception_at_thread_exit(current_exception());
2120    }
2121#endif // _LIBCPP_NO_EXCEPTIONS
2122}
2123
2124template<class ..._ArgTypes>
2125void
2126packaged_task<void(_ArgTypes...)>::reset()
2127{
2128    if (!valid())
2129        __throw_future_error(future_errc::no_state);
2130    __p_ = promise<result_type>();
2131}
2132
2133template <class _Rp, class... _ArgTypes>
2134inline _LIBCPP_INLINE_VISIBILITY
2135void
2136swap(packaged_task<_Rp(_ArgTypes...)>& __x, packaged_task<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
2137{
2138    __x.swap(__y);
2139}
2140
2141template <class _Callable, class _Alloc>
2142struct _LIBCPP_TEMPLATE_VIS uses_allocator<packaged_task<_Callable>, _Alloc>
2143    : public true_type {};
2144
2145template <class _Rp, class _Fp>
2146_LIBCPP_INLINE_VISIBILITY future<_Rp>
2147__make_deferred_assoc_state(_Fp&& __f)
2148{
2149    unique_ptr<__deferred_assoc_state<_Rp, _Fp>, __release_shared_count>
2150        __h(new __deferred_assoc_state<_Rp, _Fp>(_VSTD::forward<_Fp>(__f)));
2151    return future<_Rp>(__h.get());
2152}
2153
2154template <class _Rp, class _Fp>
2155_LIBCPP_INLINE_VISIBILITY future<_Rp>
2156__make_async_assoc_state(_Fp&& __f)
2157{
2158    unique_ptr<__async_assoc_state<_Rp, _Fp>, __release_shared_count>
2159        __h(new __async_assoc_state<_Rp, _Fp>(_VSTD::forward<_Fp>(__f)));
2160    _VSTD::thread(&__async_assoc_state<_Rp, _Fp>::__execute, __h.get()).detach();
2161    return future<_Rp>(__h.get());
2162}
2163
2164#ifndef _LIBCPP_CXX03_LANG
2165
2166template <class _Fp, class... _Args>
2167class _LIBCPP_HIDDEN __async_func
2168{
2169    tuple<_Fp, _Args...> __f_;
2170
2171public:
2172    typedef typename __invoke_of<_Fp, _Args...>::type _Rp;
2173
2174    _LIBCPP_INLINE_VISIBILITY
2175    explicit __async_func(_Fp&& __f, _Args&&... __args)
2176        : __f_(_VSTD::move(__f), _VSTD::move(__args)...) {}
2177
2178    _LIBCPP_INLINE_VISIBILITY
2179    __async_func(__async_func&& __f) : __f_(_VSTD::move(__f.__f_)) {}
2180
2181    _Rp operator()()
2182    {
2183        typedef typename __make_tuple_indices<1+sizeof...(_Args), 1>::type _Index;
2184        return __execute(_Index());
2185    }
2186private:
2187    template <size_t ..._Indices>
2188    _Rp
2189    __execute(__tuple_indices<_Indices...>)
2190    {
2191        return _VSTD::__invoke(_VSTD::move(_VSTD::get<0>(__f_)), _VSTD::move(_VSTD::get<_Indices>(__f_))...);
2192    }
2193};
2194
2195inline _LIBCPP_INLINE_VISIBILITY bool __does_policy_contain(launch __policy, launch __value )
2196{ return (int(__policy) & int(__value)) != 0; }
2197
2198template <class _Fp, class... _Args>
2199_LIBCPP_NODISCARD_AFTER_CXX17
2200future<typename __invoke_of<typename decay<_Fp>::type, typename decay<_Args>::type...>::type>
2201async(launch __policy, _Fp&& __f, _Args&&... __args)
2202{
2203    typedef __async_func<typename decay<_Fp>::type, typename decay<_Args>::type...> _BF;
2204    typedef typename _BF::_Rp _Rp;
2205
2206#ifndef _LIBCPP_NO_EXCEPTIONS
2207    try
2208    {
2209#endif
2210        if (__does_policy_contain(__policy, launch::async))
2211        return _VSTD::__make_async_assoc_state<_Rp>(_BF(_LIBCPP_AUTO_CAST(_VSTD::forward<_Fp>(__f)),
2212                                                        _LIBCPP_AUTO_CAST(_VSTD::forward<_Args>(__args))...));
2213#ifndef _LIBCPP_NO_EXCEPTIONS
2214    }
2215    catch ( ... ) { if (__policy == launch::async) throw ; }
2216#endif
2217
2218    if (__does_policy_contain(__policy, launch::deferred))
2219        return _VSTD::__make_deferred_assoc_state<_Rp>(_BF(_LIBCPP_AUTO_CAST(_VSTD::forward<_Fp>(__f)),
2220                                                           _LIBCPP_AUTO_CAST(_VSTD::forward<_Args>(__args))...));
2221    return future<_Rp>{};
2222}
2223
2224template <class _Fp, class... _Args>
2225_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY
2226future<typename __invoke_of<typename decay<_Fp>::type, typename decay<_Args>::type...>::type>
2227async(_Fp&& __f, _Args&&... __args)
2228{
2229    return _VSTD::async(launch::any, _VSTD::forward<_Fp>(__f),
2230                                    _VSTD::forward<_Args>(__args)...);
2231}
2232
2233#endif // C++03
2234
2235// shared_future
2236
2237template <class _Rp>
2238class _LIBCPP_TEMPLATE_VIS shared_future
2239{
2240    __assoc_state<_Rp>* __state_;
2241
2242public:
2243    _LIBCPP_INLINE_VISIBILITY
2244    shared_future() _NOEXCEPT : __state_(nullptr) {}
2245    _LIBCPP_INLINE_VISIBILITY
2246    shared_future(const shared_future& __rhs)  _NOEXCEPT : __state_(__rhs.__state_)
2247        {if (__state_) __state_->__add_shared();}
2248    _LIBCPP_INLINE_VISIBILITY
2249    shared_future(future<_Rp>&& __f) _NOEXCEPT : __state_(__f.__state_)
2250        {__f.__state_ = nullptr;}
2251    _LIBCPP_INLINE_VISIBILITY
2252    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
2253        {__rhs.__state_ = nullptr;}
2254    ~shared_future();
2255    shared_future& operator=(const shared_future& __rhs) _NOEXCEPT;
2256    _LIBCPP_INLINE_VISIBILITY
2257    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
2258        {
2259            shared_future(_VSTD::move(__rhs)).swap(*this);
2260            return *this;
2261        }
2262
2263    // retrieving the value
2264    _LIBCPP_INLINE_VISIBILITY
2265    const _Rp& get() const {return __state_->copy();}
2266
2267    _LIBCPP_INLINE_VISIBILITY
2268    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
2269
2270    // functions to check state
2271    _LIBCPP_INLINE_VISIBILITY
2272    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
2273
2274    _LIBCPP_INLINE_VISIBILITY
2275    void wait() const {__state_->wait();}
2276    template <class _Rep, class _Period>
2277        _LIBCPP_INLINE_VISIBILITY
2278        future_status
2279        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
2280            {return __state_->wait_for(__rel_time);}
2281    template <class _Clock, class _Duration>
2282        _LIBCPP_INLINE_VISIBILITY
2283        future_status
2284        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
2285            {return __state_->wait_until(__abs_time);}
2286};
2287
2288template <class _Rp>
2289shared_future<_Rp>::~shared_future()
2290{
2291    if (__state_)
2292        __state_->__release_shared();
2293}
2294
2295template <class _Rp>
2296shared_future<_Rp>&
2297shared_future<_Rp>::operator=(const shared_future& __rhs) _NOEXCEPT
2298{
2299    if (__rhs.__state_)
2300        __rhs.__state_->__add_shared();
2301    if (__state_)
2302        __state_->__release_shared();
2303    __state_ = __rhs.__state_;
2304    return *this;
2305}
2306
2307template <class _Rp>
2308class _LIBCPP_TEMPLATE_VIS shared_future<_Rp&>
2309{
2310    __assoc_state<_Rp&>* __state_;
2311
2312public:
2313    _LIBCPP_INLINE_VISIBILITY
2314    shared_future() _NOEXCEPT : __state_(nullptr) {}
2315    _LIBCPP_INLINE_VISIBILITY
2316    shared_future(const shared_future& __rhs) : __state_(__rhs.__state_)
2317        {if (__state_) __state_->__add_shared();}
2318    _LIBCPP_INLINE_VISIBILITY
2319    shared_future(future<_Rp&>&& __f) _NOEXCEPT : __state_(__f.__state_)
2320        {__f.__state_ = nullptr;}
2321    _LIBCPP_INLINE_VISIBILITY
2322    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
2323        {__rhs.__state_ = nullptr;}
2324    ~shared_future();
2325    shared_future& operator=(const shared_future& __rhs);
2326    _LIBCPP_INLINE_VISIBILITY
2327    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
2328        {
2329            shared_future(_VSTD::move(__rhs)).swap(*this);
2330            return *this;
2331        }
2332
2333    // retrieving the value
2334    _LIBCPP_INLINE_VISIBILITY
2335    _Rp& get() const {return __state_->copy();}
2336
2337    _LIBCPP_INLINE_VISIBILITY
2338    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
2339
2340    // functions to check state
2341    _LIBCPP_INLINE_VISIBILITY
2342    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
2343
2344    _LIBCPP_INLINE_VISIBILITY
2345    void wait() const {__state_->wait();}
2346    template <class _Rep, class _Period>
2347        _LIBCPP_INLINE_VISIBILITY
2348        future_status
2349        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
2350            {return __state_->wait_for(__rel_time);}
2351    template <class _Clock, class _Duration>
2352        _LIBCPP_INLINE_VISIBILITY
2353        future_status
2354        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
2355            {return __state_->wait_until(__abs_time);}
2356};
2357
2358template <class _Rp>
2359shared_future<_Rp&>::~shared_future()
2360{
2361    if (__state_)
2362        __state_->__release_shared();
2363}
2364
2365template <class _Rp>
2366shared_future<_Rp&>&
2367shared_future<_Rp&>::operator=(const shared_future& __rhs)
2368{
2369    if (__rhs.__state_)
2370        __rhs.__state_->__add_shared();
2371    if (__state_)
2372        __state_->__release_shared();
2373    __state_ = __rhs.__state_;
2374    return *this;
2375}
2376
2377template <>
2378class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE shared_future<void>
2379{
2380    __assoc_sub_state* __state_;
2381
2382public:
2383    _LIBCPP_INLINE_VISIBILITY
2384    shared_future() _NOEXCEPT : __state_(nullptr) {}
2385    _LIBCPP_INLINE_VISIBILITY
2386    shared_future(const shared_future& __rhs) : __state_(__rhs.__state_)
2387        {if (__state_) __state_->__add_shared();}
2388    _LIBCPP_INLINE_VISIBILITY
2389    shared_future(future<void>&& __f) _NOEXCEPT : __state_(__f.__state_)
2390        {__f.__state_ = nullptr;}
2391    _LIBCPP_INLINE_VISIBILITY
2392    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
2393        {__rhs.__state_ = nullptr;}
2394    ~shared_future();
2395    shared_future& operator=(const shared_future& __rhs);
2396    _LIBCPP_INLINE_VISIBILITY
2397    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
2398        {
2399            shared_future(_VSTD::move(__rhs)).swap(*this);
2400            return *this;
2401        }
2402
2403    // retrieving the value
2404    _LIBCPP_INLINE_VISIBILITY
2405    void get() const {__state_->copy();}
2406
2407    _LIBCPP_INLINE_VISIBILITY
2408    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
2409
2410    // functions to check state
2411    _LIBCPP_INLINE_VISIBILITY
2412    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
2413
2414    _LIBCPP_INLINE_VISIBILITY
2415    void wait() const {__state_->wait();}
2416    template <class _Rep, class _Period>
2417        _LIBCPP_INLINE_VISIBILITY
2418        future_status
2419        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
2420            {return __state_->wait_for(__rel_time);}
2421    template <class _Clock, class _Duration>
2422        _LIBCPP_INLINE_VISIBILITY
2423        future_status
2424        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
2425            {return __state_->wait_until(__abs_time);}
2426};
2427
2428template <class _Rp>
2429inline _LIBCPP_INLINE_VISIBILITY
2430void
2431swap(shared_future<_Rp>& __x, shared_future<_Rp>& __y) _NOEXCEPT
2432{
2433    __x.swap(__y);
2434}
2435
2436template <class _Rp>
2437inline
2438shared_future<_Rp>
2439future<_Rp>::share() _NOEXCEPT
2440{
2441    return shared_future<_Rp>(_VSTD::move(*this));
2442}
2443
2444template <class _Rp>
2445inline
2446shared_future<_Rp&>
2447future<_Rp&>::share() _NOEXCEPT
2448{
2449    return shared_future<_Rp&>(_VSTD::move(*this));
2450}
2451
2452inline
2453shared_future<void>
2454future<void>::share() _NOEXCEPT
2455{
2456    return shared_future<void>(_VSTD::move(*this));
2457}
2458
2459_LIBCPP_END_NAMESPACE_STD
2460
2461#endif // !_LIBCPP_HAS_NO_THREADS
2462
2463#endif // _LIBCPP_FUTURE
2464