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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___CXX03_FUTURE11#define _LIBCPP___CXX03_FUTURE12 13/*14    future synopsis15 16namespace std17{18 19enum class future_errc20{21    future_already_retrieved = 1,22    promise_already_satisfied,23    no_state,24    broken_promise25};26 27enum class launch28{29    async = 1,30    deferred = 2,31    any = async | deferred32};33 34enum class future_status35{36    ready,37    timeout,38    deferred39};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 : public logic_error {48public:49    explicit future_error(future_errc e); // since C++1750 51    const error_code& code() const noexcept;52    const char*       what() const noexcept;53 54private:55    error_code ec_;             // exposition only56};57 58template <class R>59class promise60{61public:62    promise();63    template <class Allocator>64        promise(allocator_arg_t, const Allocator& a);65    promise(promise&& rhs) noexcept;66    promise(const promise& rhs) = delete;67    ~promise();68 69    // assignment70    promise& operator=(promise&& rhs) noexcept;71    promise& operator=(const promise& rhs) = delete;72    void swap(promise& other) noexcept;73 74    // retrieving the result75    future<R> get_future();76 77    // setting the result78    void set_value(const R& r);79    void set_value(R&& r);80    void set_exception(exception_ptr p);81 82    // setting the result with deferred notification83    void set_value_at_thread_exit(const R& r);84    void set_value_at_thread_exit(R&& r);85    void set_exception_at_thread_exit(exception_ptr p);86};87 88template <class R>89class promise<R&>90{91public:92    promise();93    template <class Allocator>94        promise(allocator_arg_t, const Allocator& a);95    promise(promise&& rhs) noexcept;96    promise(const promise& rhs) = delete;97    ~promise();98 99    // assignment100    promise& operator=(promise&& rhs) noexcept;101    promise& operator=(const promise& rhs) = delete;102    void swap(promise& other) noexcept;103 104    // retrieving the result105    future<R&> get_future();106 107    // setting the result108    void set_value(R& r);109    void set_exception(exception_ptr p);110 111    // setting the result with deferred notification112    void set_value_at_thread_exit(R&);113    void set_exception_at_thread_exit(exception_ptr p);114};115 116template <>117class promise<void>118{119public:120    promise();121    template <class Allocator>122        promise(allocator_arg_t, const Allocator& a);123    promise(promise&& rhs) noexcept;124    promise(const promise& rhs) = delete;125    ~promise();126 127    // assignment128    promise& operator=(promise&& rhs) noexcept;129    promise& operator=(const promise& rhs) = delete;130    void swap(promise& other) noexcept;131 132    // retrieving the result133    future<void> get_future();134 135    // setting the result136    void set_value();137    void set_exception(exception_ptr p);138 139    // setting the result with deferred notification140    void set_value_at_thread_exit();141    void set_exception_at_thread_exit(exception_ptr p);142};143 144template <class R> void swap(promise<R>& x, promise<R>& y) noexcept;145 146template <class R, class Alloc>147    struct uses_allocator<promise<R>, Alloc> : public true_type {};148 149template <class R>150class future151{152public:153    future() noexcept;154    future(future&&) noexcept;155    future(const future& rhs) = delete;156    ~future();157    future& operator=(const future& rhs) = delete;158    future& operator=(future&&) noexcept;159    shared_future<R> share() noexcept;160 161    // retrieving the value162    R get();163 164    // functions to check state165    bool valid() const noexcept;166 167    void wait() const;168    template <class Rep, class Period>169        future_status170        wait_for(const chrono::duration<Rep, Period>& rel_time) const;171    template <class Clock, class Duration>172        future_status173        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;174};175 176template <class R>177class future<R&>178{179public:180    future() noexcept;181    future(future&&) noexcept;182    future(const future& rhs) = delete;183    ~future();184    future& operator=(const future& rhs) = delete;185    future& operator=(future&&) noexcept;186    shared_future<R&> share() noexcept;187 188    // retrieving the value189    R& get();190 191    // functions to check state192    bool valid() const noexcept;193 194    void wait() const;195    template <class Rep, class Period>196        future_status197        wait_for(const chrono::duration<Rep, Period>& rel_time) const;198    template <class Clock, class Duration>199        future_status200        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;201};202 203template <>204class future<void>205{206public:207    future() noexcept;208    future(future&&) noexcept;209    future(const future& rhs) = delete;210    ~future();211    future& operator=(const future& rhs) = delete;212    future& operator=(future&&) noexcept;213    shared_future<void> share() noexcept;214 215    // retrieving the value216    void get();217 218    // functions to check state219    bool valid() const noexcept;220 221    void wait() const;222    template <class Rep, class Period>223        future_status224        wait_for(const chrono::duration<Rep, Period>& rel_time) const;225    template <class Clock, class Duration>226        future_status227        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;228};229 230template <class R>231class shared_future232{233public:234    shared_future() noexcept;235    shared_future(const shared_future& rhs);236    shared_future(future<R>&&) noexcept;237    shared_future(shared_future&& rhs) noexcept;238    ~shared_future();239    shared_future& operator=(const shared_future& rhs);240    shared_future& operator=(shared_future&& rhs) noexcept;241 242    // retrieving the value243    const R& get() const;244 245    // functions to check state246    bool valid() const noexcept;247 248    void wait() const;249    template <class Rep, class Period>250        future_status251        wait_for(const chrono::duration<Rep, Period>& rel_time) const;252    template <class Clock, class Duration>253        future_status254        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;255};256 257template <class R>258class shared_future<R&>259{260public:261    shared_future() noexcept;262    shared_future(const shared_future& rhs);263    shared_future(future<R&>&&) noexcept;264    shared_future(shared_future&& rhs) noexcept;265    ~shared_future();266    shared_future& operator=(const shared_future& rhs);267    shared_future& operator=(shared_future&& rhs) noexcept;268 269    // retrieving the value270    R& get() const;271 272    // functions to check state273    bool valid() const noexcept;274 275    void wait() const;276    template <class Rep, class Period>277        future_status278        wait_for(const chrono::duration<Rep, Period>& rel_time) const;279    template <class Clock, class Duration>280        future_status281        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;282};283 284template <>285class shared_future<void>286{287public:288    shared_future() noexcept;289    shared_future(const shared_future& rhs);290    shared_future(future<void>&&) noexcept;291    shared_future(shared_future&& rhs) noexcept;292    ~shared_future();293    shared_future& operator=(const shared_future& rhs);294    shared_future& operator=(shared_future&& rhs) noexcept;295 296    // retrieving the value297    void get() const;298 299    // functions to check state300    bool valid() const noexcept;301 302    void wait() const;303    template <class Rep, class Period>304        future_status305        wait_for(const chrono::duration<Rep, Period>& rel_time) const;306    template <class Clock, class Duration>307        future_status308        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;309};310 311template <class F, class... Args>312  future<typename result_of<typename decay<F>::type(typename decay<Args>::type...)>::type>313  async(F&& f, Args&&... args);314 315template <class F, class... Args>316  future<typename result_of<typename decay<F>::type(typename decay<Args>::type...)>::type>317  async(launch policy, F&& f, Args&&... args);318 319template <class> class packaged_task; // undefined320 321template <class R, class... ArgTypes>322class packaged_task<R(ArgTypes...)>323{324public:325    typedef R result_type; // extension326 327    // construction and destruction328    packaged_task() noexcept;329    template <class F>330        explicit packaged_task(F&& f);331    template <class F, class Allocator>332        packaged_task(allocator_arg_t, const Allocator& a, F&& f);333    ~packaged_task();334 335    // no copy336    packaged_task(const packaged_task&) = delete;337    packaged_task& operator=(const packaged_task&) = delete;338 339    // move support340    packaged_task(packaged_task&& other) noexcept;341    packaged_task& operator=(packaged_task&& other) noexcept;342    void swap(packaged_task& other) noexcept;343 344    bool valid() const noexcept;345 346    // result retrieval347    future<R> get_future();348 349    // execution350    void operator()(ArgTypes... );351    void make_ready_at_thread_exit(ArgTypes...);352 353    void reset();354};355 356template <class R>357  void swap(packaged_task<R(ArgTypes...)&, packaged_task<R(ArgTypes...)>&) noexcept;358 359template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;360 361}  // std362 363*/364 365#include <__cxx03/__config>366 367#if !defined(_LIBCPP_HAS_NO_THREADS)368 369#  include <__cxx03/__assert>370#  include <__cxx03/__chrono/duration.h>371#  include <__cxx03/__chrono/time_point.h>372#  include <__cxx03/__exception/exception_ptr.h>373#  include <__cxx03/__memory/addressof.h>374#  include <__cxx03/__memory/allocator.h>375#  include <__cxx03/__memory/allocator_arg_t.h>376#  include <__cxx03/__memory/allocator_destructor.h>377#  include <__cxx03/__memory/allocator_traits.h>378#  include <__cxx03/__memory/compressed_pair.h>379#  include <__cxx03/__memory/pointer_traits.h>380#  include <__cxx03/__memory/shared_ptr.h>381#  include <__cxx03/__memory/unique_ptr.h>382#  include <__cxx03/__memory/uses_allocator.h>383#  include <__cxx03/__system_error/error_category.h>384#  include <__cxx03/__system_error/error_code.h>385#  include <__cxx03/__system_error/error_condition.h>386#  include <__cxx03/__type_traits/aligned_storage.h>387#  include <__cxx03/__type_traits/strip_signature.h>388#  include <__cxx03/__utility/auto_cast.h>389#  include <__cxx03/__utility/forward.h>390#  include <__cxx03/__utility/move.h>391#  include <__cxx03/mutex>392#  include <__cxx03/new>393#  include <__cxx03/stdexcept>394#  include <__cxx03/thread>395#  include <__cxx03/version>396 397#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)398#    pragma GCC system_header399#  endif400 401_LIBCPP_PUSH_MACROS402#  include <__cxx03/__undef_macros>403 404_LIBCPP_BEGIN_NAMESPACE_STD405 406// enum class future_errc407_LIBCPP_DECLARE_STRONG_ENUM(future_errc){408    future_already_retrieved = 1, promise_already_satisfied, no_state, broken_promise};409_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_errc)410 411template <>412struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc> : public true_type {};413 414template <>415struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc::__lx> : public true_type {};416 417// enum class launch418_LIBCPP_DECLARE_STRONG_ENUM(launch){async = 1, deferred = 2, any = async | deferred};419_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(launch)420 421// enum class future_status422_LIBCPP_DECLARE_STRONG_ENUM(future_status){ready, timeout, deferred};423_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_status)424 425_LIBCPP_EXPORTED_FROM_ABI const error_category& future_category() _NOEXCEPT;426 427inline _LIBCPP_HIDE_FROM_ABI error_code make_error_code(future_errc __e) _NOEXCEPT {428  return error_code(static_cast<int>(__e), future_category());429}430 431inline _LIBCPP_HIDE_FROM_ABI error_condition make_error_condition(future_errc __e) _NOEXCEPT {432  return error_condition(static_cast<int>(__e), future_category());433}434 435_LIBCPP_NORETURN inline _LIBCPP_HIDE_FROM_ABI void __throw_future_error(future_errc __ev);436 437class _LIBCPP_EXPORTED_FROM_ABI future_error : public logic_error {438  error_code __ec_;439 440  future_error(error_code);441  friend void __throw_future_error(future_errc);442  template <class>443  friend class promise;444 445public:446  _LIBCPP_HIDE_FROM_ABI const error_code& code() const _NOEXCEPT { return __ec_; }447 448  _LIBCPP_HIDE_FROM_ABI future_error(const future_error&) _NOEXCEPT = default;449  ~future_error() _NOEXCEPT override;450};451 452// Declared above std::future_error453void __throw_future_error(future_errc __ev) {454#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS455  throw future_error(make_error_code(__ev));456#  else457  (void)__ev;458  _LIBCPP_VERBOSE_ABORT("future_error was thrown in -fno-exceptions mode");459#  endif460}461 462class _LIBCPP_EXPORTED_FROM_ABI __assoc_sub_state : public __shared_count {463protected:464  exception_ptr __exception_;465  mutable mutex __mut_;466  mutable condition_variable __cv_;467  unsigned __state_;468 469  void __on_zero_shared() _NOEXCEPT override;470  void __sub_wait(unique_lock<mutex>& __lk);471 472public:473  enum { __constructed = 1, __future_attached = 2, ready = 4, deferred = 8 };474 475  _LIBCPP_HIDE_FROM_ABI __assoc_sub_state() : __state_(0) {}476 477  _LIBCPP_HIDE_FROM_ABI bool __has_value() const { return (__state_ & __constructed) || (__exception_ != nullptr); }478 479  _LIBCPP_HIDE_FROM_ABI void __attach_future() {480    lock_guard<mutex> __lk(__mut_);481    bool __has_future_attached = (__state_ & __future_attached) != 0;482    if (__has_future_attached)483      __throw_future_error(future_errc::future_already_retrieved);484    this->__add_shared();485    __state_ |= __future_attached;486  }487 488  _LIBCPP_HIDE_FROM_ABI void __set_deferred() { __state_ |= deferred; }489 490  void __make_ready();491  _LIBCPP_HIDE_FROM_ABI bool __is_ready() const { return (__state_ & ready) != 0; }492 493  void set_value();494  void set_value_at_thread_exit();495 496  void set_exception(exception_ptr __p);497  void set_exception_at_thread_exit(exception_ptr __p);498 499  void copy();500 501  void wait();502  template <class _Rep, class _Period>503  future_status _LIBCPP_HIDE_FROM_ABI wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const;504  template <class _Clock, class _Duration>505  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS future_status506  wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const;507 508  virtual void __execute();509};510 511template <class _Clock, class _Duration>512future_status __assoc_sub_state::wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {513  unique_lock<mutex> __lk(__mut_);514  if (__state_ & deferred)515    return future_status::deferred;516  while (!(__state_ & ready) && _Clock::now() < __abs_time)517    __cv_.wait_until(__lk, __abs_time);518  if (__state_ & ready)519    return future_status::ready;520  return future_status::timeout;521}522 523template <class _Rep, class _Period>524inline future_status __assoc_sub_state::wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {525  return wait_until(chrono::steady_clock::now() + __rel_time);526}527 528template <class _Rp>529class _LIBCPP_HIDDEN __assoc_state : public __assoc_sub_state {530  typedef __assoc_sub_state base;531  _LIBCPP_SUPPRESS_DEPRECATED_PUSH532  typedef typename aligned_storage<sizeof(_Rp), _LIBCPP_ALIGNOF(_Rp)>::type _Up;533  _LIBCPP_SUPPRESS_DEPRECATED_POP534 535protected:536  _Up __value_;537 538  _LIBCPP_HIDE_FROM_ABI_VIRTUAL void __on_zero_shared() _NOEXCEPT override;539 540public:541  template <class _Arg>542  _LIBCPP_HIDE_FROM_ABI void set_value(_Arg&& __arg);543 544  template <class _Arg>545  _LIBCPP_HIDE_FROM_ABI void set_value_at_thread_exit(_Arg&& __arg);546 547  _LIBCPP_HIDE_FROM_ABI _Rp move();548  _LIBCPP_HIDE_FROM_ABI __add_lvalue_reference_t<_Rp> copy();549};550 551template <class _Rp>552void __assoc_state<_Rp>::__on_zero_shared() _NOEXCEPT {553  if (this->__state_ & base::__constructed)554    reinterpret_cast<_Rp*>(&__value_)->~_Rp();555  delete this;556}557 558template <class _Rp>559template <class _Arg>560void __assoc_state<_Rp>::set_value(_Arg&& __arg) {561  unique_lock<mutex> __lk(this->__mut_);562  if (this->__has_value())563    __throw_future_error(future_errc::promise_already_satisfied);564  ::new ((void*)&__value_) _Rp(std::forward<_Arg>(__arg));565  this->__state_ |= base::__constructed | base::ready;566  __cv_.notify_all();567}568 569template <class _Rp>570template <class _Arg>571void __assoc_state<_Rp>::set_value_at_thread_exit(_Arg&& __arg) {572  unique_lock<mutex> __lk(this->__mut_);573  if (this->__has_value())574    __throw_future_error(future_errc::promise_already_satisfied);575  ::new ((void*)&__value_) _Rp(std::forward<_Arg>(__arg));576  this->__state_ |= base::__constructed;577  __thread_local_data()->__make_ready_at_thread_exit(this);578}579 580template <class _Rp>581_Rp __assoc_state<_Rp>::move() {582  unique_lock<mutex> __lk(this->__mut_);583  this->__sub_wait(__lk);584  if (this->__exception_ != nullptr)585    std::rethrow_exception(this->__exception_);586  return std::move(*reinterpret_cast<_Rp*>(&__value_));587}588 589template <class _Rp>590__add_lvalue_reference_t<_Rp> __assoc_state<_Rp>::copy() {591  unique_lock<mutex> __lk(this->__mut_);592  this->__sub_wait(__lk);593  if (this->__exception_ != nullptr)594    std::rethrow_exception(this->__exception_);595  return *reinterpret_cast<_Rp*>(&__value_);596}597 598template <class _Rp>599class __assoc_state<_Rp&> : public __assoc_sub_state {600  typedef __assoc_sub_state base;601  typedef _Rp* _Up;602 603protected:604  _Up __value_;605 606  _LIBCPP_HIDE_FROM_ABI_VIRTUAL void __on_zero_shared() _NOEXCEPT override;607 608public:609  _LIBCPP_HIDE_FROM_ABI void set_value(_Rp& __arg);610  _LIBCPP_HIDE_FROM_ABI void set_value_at_thread_exit(_Rp& __arg);611 612  _LIBCPP_HIDE_FROM_ABI _Rp& copy();613};614 615template <class _Rp>616void __assoc_state<_Rp&>::__on_zero_shared() _NOEXCEPT {617  delete this;618}619 620template <class _Rp>621void __assoc_state<_Rp&>::set_value(_Rp& __arg) {622  unique_lock<mutex> __lk(this->__mut_);623  if (this->__has_value())624    __throw_future_error(future_errc::promise_already_satisfied);625  __value_ = std::addressof(__arg);626  this->__state_ |= base::__constructed | base::ready;627  __cv_.notify_all();628}629 630template <class _Rp>631void __assoc_state<_Rp&>::set_value_at_thread_exit(_Rp& __arg) {632  unique_lock<mutex> __lk(this->__mut_);633  if (this->__has_value())634    __throw_future_error(future_errc::promise_already_satisfied);635  __value_ = std::addressof(__arg);636  this->__state_ |= base::__constructed;637  __thread_local_data()->__make_ready_at_thread_exit(this);638}639 640template <class _Rp>641_Rp& __assoc_state<_Rp&>::copy() {642  unique_lock<mutex> __lk(this->__mut_);643  this->__sub_wait(__lk);644  if (this->__exception_ != nullptr)645    std::rethrow_exception(this->__exception_);646  return *__value_;647}648 649template <class _Rp, class _Alloc>650class __assoc_state_alloc : public __assoc_state<_Rp> {651  typedef __assoc_state<_Rp> base;652  _Alloc __alloc_;653 654  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void __on_zero_shared() _NOEXCEPT;655 656public:657  _LIBCPP_HIDE_FROM_ABI explicit __assoc_state_alloc(const _Alloc& __a) : __alloc_(__a) {}658};659 660template <class _Rp, class _Alloc>661void __assoc_state_alloc<_Rp, _Alloc>::__on_zero_shared() _NOEXCEPT {662  if (this->__state_ & base::__constructed)663    reinterpret_cast<_Rp*>(std::addressof(this->__value_))->~_Rp();664  typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;665  typedef allocator_traits<_Al> _ATraits;666  typedef pointer_traits<typename _ATraits::pointer> _PTraits;667  _Al __a(__alloc_);668  this->~__assoc_state_alloc();669  __a.deallocate(_PTraits::pointer_to(*this), 1);670}671 672template <class _Rp, class _Alloc>673class __assoc_state_alloc<_Rp&, _Alloc> : public __assoc_state<_Rp&> {674  typedef __assoc_state<_Rp&> base;675  _Alloc __alloc_;676 677  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void __on_zero_shared() _NOEXCEPT;678 679public:680  _LIBCPP_HIDE_FROM_ABI explicit __assoc_state_alloc(const _Alloc& __a) : __alloc_(__a) {}681};682 683template <class _Rp, class _Alloc>684void __assoc_state_alloc<_Rp&, _Alloc>::__on_zero_shared() _NOEXCEPT {685  typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;686  typedef allocator_traits<_Al> _ATraits;687  typedef pointer_traits<typename _ATraits::pointer> _PTraits;688  _Al __a(__alloc_);689  this->~__assoc_state_alloc();690  __a.deallocate(_PTraits::pointer_to(*this), 1);691}692 693template <class _Alloc>694class __assoc_sub_state_alloc : public __assoc_sub_state {695  typedef __assoc_sub_state base;696  _Alloc __alloc_;697 698  _LIBCPP_HIDE_FROM_ABI_VIRTUAL void __on_zero_shared() _NOEXCEPT override;699 700public:701  _LIBCPP_HIDE_FROM_ABI explicit __assoc_sub_state_alloc(const _Alloc& __a) : __alloc_(__a) {}702};703 704template <class _Alloc>705void __assoc_sub_state_alloc<_Alloc>::__on_zero_shared() _NOEXCEPT {706  typedef typename __allocator_traits_rebind<_Alloc, __assoc_sub_state_alloc>::type _Al;707  typedef allocator_traits<_Al> _ATraits;708  typedef pointer_traits<typename _ATraits::pointer> _PTraits;709  _Al __a(__alloc_);710  this->~__assoc_sub_state_alloc();711  __a.deallocate(_PTraits::pointer_to(*this), 1);712}713 714template <class _Rp, class _Fp>715class __deferred_assoc_state : public __assoc_state<_Rp> {716  typedef __assoc_state<_Rp> base;717 718  _Fp __func_;719 720public:721  _LIBCPP_HIDE_FROM_ABI explicit __deferred_assoc_state(_Fp&& __f);722 723  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void __execute();724};725 726template <class _Rp, class _Fp>727inline __deferred_assoc_state<_Rp, _Fp>::__deferred_assoc_state(_Fp&& __f) : __func_(std::forward<_Fp>(__f)) {728  this->__set_deferred();729}730 731template <class _Rp, class _Fp>732void __deferred_assoc_state<_Rp, _Fp>::__execute() {733#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS734  try {735#  endif // _LIBCPP_HAS_NO_EXCEPTIONS736    this->set_value(__func_());737#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS738  } catch (...) {739    this->set_exception(current_exception());740  }741#  endif // _LIBCPP_HAS_NO_EXCEPTIONS742}743 744template <class _Fp>745class __deferred_assoc_state<void, _Fp> : public __assoc_sub_state {746  typedef __assoc_sub_state base;747 748  _Fp __func_;749 750public:751  _LIBCPP_HIDE_FROM_ABI explicit __deferred_assoc_state(_Fp&& __f);752 753  _LIBCPP_HIDE_FROM_ABI_VIRTUAL void __execute() override;754};755 756template <class _Fp>757inline __deferred_assoc_state<void, _Fp>::__deferred_assoc_state(_Fp&& __f) : __func_(std::forward<_Fp>(__f)) {758  this->__set_deferred();759}760 761template <class _Fp>762void __deferred_assoc_state<void, _Fp>::__execute() {763#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS764  try {765#  endif // _LIBCPP_HAS_NO_EXCEPTIONS766    __func_();767    this->set_value();768#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS769  } catch (...) {770    this->set_exception(current_exception());771  }772#  endif // _LIBCPP_HAS_NO_EXCEPTIONS773}774 775template <class _Rp, class _Fp>776class __async_assoc_state : public __assoc_state<_Rp> {777  typedef __assoc_state<_Rp> base;778 779  _Fp __func_;780 781  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void __on_zero_shared() _NOEXCEPT;782 783public:784  _LIBCPP_HIDE_FROM_ABI explicit __async_assoc_state(_Fp&& __f);785 786  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void __execute();787};788 789template <class _Rp, class _Fp>790inline __async_assoc_state<_Rp, _Fp>::__async_assoc_state(_Fp&& __f) : __func_(std::forward<_Fp>(__f)) {}791 792template <class _Rp, class _Fp>793void __async_assoc_state<_Rp, _Fp>::__execute() {794#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS795  try {796#  endif // _LIBCPP_HAS_NO_EXCEPTIONS797    this->set_value(__func_());798#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS799  } catch (...) {800    this->set_exception(current_exception());801  }802#  endif // _LIBCPP_HAS_NO_EXCEPTIONS803}804 805template <class _Rp, class _Fp>806void __async_assoc_state<_Rp, _Fp>::__on_zero_shared() _NOEXCEPT {807  this->wait();808  base::__on_zero_shared();809}810 811template <class _Fp>812class __async_assoc_state<void, _Fp> : public __assoc_sub_state {813  typedef __assoc_sub_state base;814 815  _Fp __func_;816 817  _LIBCPP_HIDE_FROM_ABI_VIRTUAL void __on_zero_shared() _NOEXCEPT override;818 819public:820  _LIBCPP_HIDE_FROM_ABI explicit __async_assoc_state(_Fp&& __f);821 822  _LIBCPP_HIDE_FROM_ABI_VIRTUAL void __execute() override;823};824 825template <class _Fp>826inline __async_assoc_state<void, _Fp>::__async_assoc_state(_Fp&& __f) : __func_(std::forward<_Fp>(__f)) {}827 828template <class _Fp>829void __async_assoc_state<void, _Fp>::__execute() {830#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS831  try {832#  endif // _LIBCPP_HAS_NO_EXCEPTIONS833    __func_();834    this->set_value();835#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS836  } catch (...) {837    this->set_exception(current_exception());838  }839#  endif // _LIBCPP_HAS_NO_EXCEPTIONS840}841 842template <class _Fp>843void __async_assoc_state<void, _Fp>::__on_zero_shared() _NOEXCEPT {844  this->wait();845  base::__on_zero_shared();846}847 848template <class _Rp>849class _LIBCPP_TEMPLATE_VIS promise;850template <class _Rp>851class _LIBCPP_TEMPLATE_VIS shared_future;852 853// future854 855template <class _Rp>856class _LIBCPP_TEMPLATE_VIS future;857 858template <class _Rp, class _Fp>859_LIBCPP_HIDE_FROM_ABI future<_Rp> __make_deferred_assoc_state(_Fp&& __f);860 861template <class _Rp, class _Fp>862_LIBCPP_HIDE_FROM_ABI future<_Rp> __make_async_assoc_state(_Fp&& __f);863 864template <class _Rp>865class _LIBCPP_TEMPLATE_VIS future {866  __assoc_state<_Rp>* __state_;867 868  explicit _LIBCPP_HIDE_FROM_ABI future(__assoc_state<_Rp>* __state);869 870  template <class>871  friend class promise;872  template <class>873  friend class shared_future;874 875  template <class _R1, class _Fp>876  friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);877  template <class _R1, class _Fp>878  friend future<_R1> __make_async_assoc_state(_Fp&& __f);879 880public:881  _LIBCPP_HIDE_FROM_ABI future() _NOEXCEPT : __state_(nullptr) {}882  _LIBCPP_HIDE_FROM_ABI future(future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) { __rhs.__state_ = nullptr; }883  future(const future&)            = delete;884  future& operator=(const future&) = delete;885  _LIBCPP_HIDE_FROM_ABI future& operator=(future&& __rhs) _NOEXCEPT {886    future(std::move(__rhs)).swap(*this);887    return *this;888  }889 890  _LIBCPP_HIDE_FROM_ABI ~future();891  _LIBCPP_HIDE_FROM_ABI shared_future<_Rp> share() _NOEXCEPT;892 893  // retrieving the value894  _LIBCPP_HIDE_FROM_ABI _Rp get();895 896  _LIBCPP_HIDE_FROM_ABI void swap(future& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }897 898  // functions to check state899  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __state_ != nullptr; }900 901  _LIBCPP_HIDE_FROM_ABI void wait() const { __state_->wait(); }902  template <class _Rep, class _Period>903  _LIBCPP_HIDE_FROM_ABI future_status wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {904    return __state_->wait_for(__rel_time);905  }906  template <class _Clock, class _Duration>907  _LIBCPP_HIDE_FROM_ABI future_status wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {908    return __state_->wait_until(__abs_time);909  }910};911 912template <class _Rp>913future<_Rp>::future(__assoc_state<_Rp>* __state) : __state_(__state) {914  __state_->__attach_future();915}916 917struct __release_shared_count {918  _LIBCPP_HIDE_FROM_ABI void operator()(__shared_count* __p) { __p->__release_shared(); }919};920 921template <class _Rp>922future<_Rp>::~future() {923  if (__state_)924    __state_->__release_shared();925}926 927template <class _Rp>928_Rp future<_Rp>::get() {929  unique_ptr<__shared_count, __release_shared_count> __guard(__state_);930  __assoc_state<_Rp>* __s = __state_;931  __state_                = nullptr;932  return __s->move();933}934 935template <class _Rp>936class _LIBCPP_TEMPLATE_VIS future<_Rp&> {937  __assoc_state<_Rp&>* __state_;938 939  explicit _LIBCPP_HIDE_FROM_ABI future(__assoc_state<_Rp&>* __state);940 941  template <class>942  friend class promise;943  template <class>944  friend class shared_future;945 946  template <class _R1, class _Fp>947  friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);948  template <class _R1, class _Fp>949  friend future<_R1> __make_async_assoc_state(_Fp&& __f);950 951public:952  _LIBCPP_HIDE_FROM_ABI future() _NOEXCEPT : __state_(nullptr) {}953  _LIBCPP_HIDE_FROM_ABI future(future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) { __rhs.__state_ = nullptr; }954  future(const future&)            = delete;955  future& operator=(const future&) = delete;956  _LIBCPP_HIDE_FROM_ABI future& operator=(future&& __rhs) _NOEXCEPT {957    future(std::move(__rhs)).swap(*this);958    return *this;959  }960 961  _LIBCPP_HIDE_FROM_ABI ~future();962  _LIBCPP_HIDE_FROM_ABI shared_future<_Rp&> share() _NOEXCEPT;963 964  // retrieving the value965  _LIBCPP_HIDE_FROM_ABI _Rp& get();966 967  _LIBCPP_HIDE_FROM_ABI void swap(future& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }968 969  // functions to check state970  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __state_ != nullptr; }971 972  _LIBCPP_HIDE_FROM_ABI void wait() const { __state_->wait(); }973  template <class _Rep, class _Period>974  _LIBCPP_HIDE_FROM_ABI future_status wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {975    return __state_->wait_for(__rel_time);976  }977  template <class _Clock, class _Duration>978  _LIBCPP_HIDE_FROM_ABI future_status wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {979    return __state_->wait_until(__abs_time);980  }981};982 983template <class _Rp>984future<_Rp&>::future(__assoc_state<_Rp&>* __state) : __state_(__state) {985  __state_->__attach_future();986}987 988template <class _Rp>989future<_Rp&>::~future() {990  if (__state_)991    __state_->__release_shared();992}993 994template <class _Rp>995_Rp& future<_Rp&>::get() {996  unique_ptr<__shared_count, __release_shared_count> __guard(__state_);997  __assoc_state<_Rp&>* __s = __state_;998  __state_                 = nullptr;999  return __s->copy();1000}1001 1002template <>1003class _LIBCPP_EXPORTED_FROM_ABI future<void> {1004  __assoc_sub_state* __state_;1005 1006  explicit future(__assoc_sub_state* __state);1007 1008  template <class>1009  friend class promise;1010  template <class>1011  friend class shared_future;1012 1013  template <class _R1, class _Fp>1014  friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);1015  template <class _R1, class _Fp>1016  friend future<_R1> __make_async_assoc_state(_Fp&& __f);1017 1018public:1019  _LIBCPP_HIDE_FROM_ABI future() _NOEXCEPT : __state_(nullptr) {}1020  _LIBCPP_HIDE_FROM_ABI future(future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) { __rhs.__state_ = nullptr; }1021  future(const future&)            = delete;1022  future& operator=(const future&) = delete;1023  _LIBCPP_HIDE_FROM_ABI future& operator=(future&& __rhs) _NOEXCEPT {1024    future(std::move(__rhs)).swap(*this);1025    return *this;1026  }1027 1028  ~future();1029  _LIBCPP_HIDE_FROM_ABI shared_future<void> share() _NOEXCEPT;1030 1031  // retrieving the value1032  void get();1033 1034  _LIBCPP_HIDE_FROM_ABI void swap(future& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1035 1036  // functions to check state1037  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __state_ != nullptr; }1038 1039  _LIBCPP_HIDE_FROM_ABI void wait() const { __state_->wait(); }1040  template <class _Rep, class _Period>1041  _LIBCPP_HIDE_FROM_ABI future_status wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {1042    return __state_->wait_for(__rel_time);1043  }1044  template <class _Clock, class _Duration>1045  _LIBCPP_HIDE_FROM_ABI future_status wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {1046    return __state_->wait_until(__abs_time);1047  }1048};1049 1050template <class _Rp>1051inline _LIBCPP_HIDE_FROM_ABI void swap(future<_Rp>& __x, future<_Rp>& __y) _NOEXCEPT {1052  __x.swap(__y);1053}1054 1055// promise<R>1056 1057template <class _Callable>1058class packaged_task;1059 1060template <class _Rp>1061class _LIBCPP_TEMPLATE_VIS promise {1062  __assoc_state<_Rp>* __state_;1063 1064  _LIBCPP_HIDE_FROM_ABI explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}1065 1066  template <class>1067  friend class packaged_task;1068 1069public:1070  _LIBCPP_HIDE_FROM_ABI promise();1071  template <class _Alloc>1072  _LIBCPP_HIDE_FROM_ABI promise(allocator_arg_t, const _Alloc& __a);1073  _LIBCPP_HIDE_FROM_ABI promise(promise&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) { __rhs.__state_ = nullptr; }1074  promise(const promise& __rhs) = delete;1075  _LIBCPP_HIDE_FROM_ABI ~promise();1076 1077  // assignment1078  _LIBCPP_HIDE_FROM_ABI promise& operator=(promise&& __rhs) _NOEXCEPT {1079    promise(std::move(__rhs)).swap(*this);1080    return *this;1081  }1082  promise& operator=(const promise& __rhs) = delete;1083 1084  _LIBCPP_HIDE_FROM_ABI void swap(promise& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1085 1086  // retrieving the result1087  _LIBCPP_HIDE_FROM_ABI future<_Rp> get_future();1088 1089  // setting the result1090  _LIBCPP_HIDE_FROM_ABI void set_value(const _Rp& __r);1091  _LIBCPP_HIDE_FROM_ABI void set_value(_Rp&& __r);1092  _LIBCPP_HIDE_FROM_ABI void set_exception(exception_ptr __p);1093 1094  // setting the result with deferred notification1095  _LIBCPP_HIDE_FROM_ABI void set_value_at_thread_exit(const _Rp& __r);1096  _LIBCPP_HIDE_FROM_ABI void set_value_at_thread_exit(_Rp&& __r);1097  _LIBCPP_HIDE_FROM_ABI void set_exception_at_thread_exit(exception_ptr __p);1098};1099 1100template <class _Rp>1101promise<_Rp>::promise() : __state_(new __assoc_state<_Rp>) {}1102 1103template <class _Rp>1104template <class _Alloc>1105promise<_Rp>::promise(allocator_arg_t, const _Alloc& __a0) {1106  typedef __assoc_state_alloc<_Rp, _Alloc> _State;1107  typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;1108  typedef __allocator_destructor<_A2> _D2;1109  _A2 __a(__a0);1110  unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));1111  ::new ((void*)std::addressof(*__hold.get())) _State(__a0);1112  __state_ = std::addressof(*__hold.release());1113}1114 1115template <class _Rp>1116promise<_Rp>::~promise() {1117  if (__state_) {1118    if (!__state_->__has_value() && __state_->use_count() > 1)1119      __state_->set_exception(make_exception_ptr(future_error(make_error_code(future_errc::broken_promise))));1120    __state_->__release_shared();1121  }1122}1123 1124template <class _Rp>1125future<_Rp> promise<_Rp>::get_future() {1126  if (__state_ == nullptr)1127    __throw_future_error(future_errc::no_state);1128  return future<_Rp>(__state_);1129}1130 1131template <class _Rp>1132void promise<_Rp>::set_value(const _Rp& __r) {1133  if (__state_ == nullptr)1134    __throw_future_error(future_errc::no_state);1135  __state_->set_value(__r);1136}1137 1138template <class _Rp>1139void promise<_Rp>::set_value(_Rp&& __r) {1140  if (__state_ == nullptr)1141    __throw_future_error(future_errc::no_state);1142  __state_->set_value(std::move(__r));1143}1144 1145template <class _Rp>1146void promise<_Rp>::set_exception(exception_ptr __p) {1147  _LIBCPP_ASSERT_NON_NULL(__p != nullptr, "promise::set_exception: received nullptr");1148  if (__state_ == nullptr)1149    __throw_future_error(future_errc::no_state);1150  __state_->set_exception(__p);1151}1152 1153template <class _Rp>1154void promise<_Rp>::set_value_at_thread_exit(const _Rp& __r) {1155  if (__state_ == nullptr)1156    __throw_future_error(future_errc::no_state);1157  __state_->set_value_at_thread_exit(__r);1158}1159 1160template <class _Rp>1161void promise<_Rp>::set_value_at_thread_exit(_Rp&& __r) {1162  if (__state_ == nullptr)1163    __throw_future_error(future_errc::no_state);1164  __state_->set_value_at_thread_exit(std::move(__r));1165}1166 1167template <class _Rp>1168void promise<_Rp>::set_exception_at_thread_exit(exception_ptr __p) {1169  _LIBCPP_ASSERT_NON_NULL(__p != nullptr, "promise::set_exception_at_thread_exit: received nullptr");1170  if (__state_ == nullptr)1171    __throw_future_error(future_errc::no_state);1172  __state_->set_exception_at_thread_exit(__p);1173}1174 1175// promise<R&>1176 1177template <class _Rp>1178class _LIBCPP_TEMPLATE_VIS promise<_Rp&> {1179  __assoc_state<_Rp&>* __state_;1180 1181  _LIBCPP_HIDE_FROM_ABI explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}1182 1183  template <class>1184  friend class packaged_task;1185 1186public:1187  _LIBCPP_HIDE_FROM_ABI promise();1188  template <class _Allocator>1189  _LIBCPP_HIDE_FROM_ABI promise(allocator_arg_t, const _Allocator& __a);1190  _LIBCPP_HIDE_FROM_ABI promise(promise&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) { __rhs.__state_ = nullptr; }1191  promise(const promise& __rhs) = delete;1192  _LIBCPP_HIDE_FROM_ABI ~promise();1193 1194  // assignment1195  _LIBCPP_HIDE_FROM_ABI promise& operator=(promise&& __rhs) _NOEXCEPT {1196    promise(std::move(__rhs)).swap(*this);1197    return *this;1198  }1199  promise& operator=(const promise& __rhs) = delete;1200 1201  _LIBCPP_HIDE_FROM_ABI void swap(promise& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1202 1203  // retrieving the result1204  _LIBCPP_HIDE_FROM_ABI future<_Rp&> get_future();1205 1206  // setting the result1207  _LIBCPP_HIDE_FROM_ABI void set_value(_Rp& __r);1208  _LIBCPP_HIDE_FROM_ABI void set_exception(exception_ptr __p);1209 1210  // setting the result with deferred notification1211  _LIBCPP_HIDE_FROM_ABI void set_value_at_thread_exit(_Rp&);1212  _LIBCPP_HIDE_FROM_ABI void set_exception_at_thread_exit(exception_ptr __p);1213};1214 1215template <class _Rp>1216promise<_Rp&>::promise() : __state_(new __assoc_state<_Rp&>) {}1217 1218template <class _Rp>1219template <class _Alloc>1220promise<_Rp&>::promise(allocator_arg_t, const _Alloc& __a0) {1221  typedef __assoc_state_alloc<_Rp&, _Alloc> _State;1222  typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;1223  typedef __allocator_destructor<_A2> _D2;1224  _A2 __a(__a0);1225  unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));1226  ::new ((void*)std::addressof(*__hold.get())) _State(__a0);1227  __state_ = std::addressof(*__hold.release());1228}1229 1230template <class _Rp>1231promise<_Rp&>::~promise() {1232  if (__state_) {1233    if (!__state_->__has_value() && __state_->use_count() > 1)1234      __state_->set_exception(make_exception_ptr(future_error(make_error_code(future_errc::broken_promise))));1235    __state_->__release_shared();1236  }1237}1238 1239template <class _Rp>1240future<_Rp&> promise<_Rp&>::get_future() {1241  if (__state_ == nullptr)1242    __throw_future_error(future_errc::no_state);1243  return future<_Rp&>(__state_);1244}1245 1246template <class _Rp>1247void promise<_Rp&>::set_value(_Rp& __r) {1248  if (__state_ == nullptr)1249    __throw_future_error(future_errc::no_state);1250  __state_->set_value(__r);1251}1252 1253template <class _Rp>1254void promise<_Rp&>::set_exception(exception_ptr __p) {1255  _LIBCPP_ASSERT_NON_NULL(__p != nullptr, "promise::set_exception: received nullptr");1256  if (__state_ == nullptr)1257    __throw_future_error(future_errc::no_state);1258  __state_->set_exception(__p);1259}1260 1261template <class _Rp>1262void promise<_Rp&>::set_value_at_thread_exit(_Rp& __r) {1263  if (__state_ == nullptr)1264    __throw_future_error(future_errc::no_state);1265  __state_->set_value_at_thread_exit(__r);1266}1267 1268template <class _Rp>1269void promise<_Rp&>::set_exception_at_thread_exit(exception_ptr __p) {1270  _LIBCPP_ASSERT_NON_NULL(__p != nullptr, "promise::set_exception_at_thread_exit: received nullptr");1271  if (__state_ == nullptr)1272    __throw_future_error(future_errc::no_state);1273  __state_->set_exception_at_thread_exit(__p);1274}1275 1276// promise<void>1277 1278template <>1279class _LIBCPP_EXPORTED_FROM_ABI promise<void> {1280  __assoc_sub_state* __state_;1281 1282  _LIBCPP_HIDE_FROM_ABI explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}1283 1284  template <class>1285  friend class packaged_task;1286 1287public:1288  promise();1289  template <class _Allocator>1290  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS promise(allocator_arg_t, const _Allocator& __a);1291  _LIBCPP_HIDE_FROM_ABI promise(promise&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) { __rhs.__state_ = nullptr; }1292  promise(const promise& __rhs) = delete;1293  ~promise();1294 1295  // assignment1296  _LIBCPP_HIDE_FROM_ABI promise& operator=(promise&& __rhs) _NOEXCEPT {1297    promise(std::move(__rhs)).swap(*this);1298    return *this;1299  }1300  promise& operator=(const promise& __rhs) = delete;1301 1302  _LIBCPP_HIDE_FROM_ABI void swap(promise& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1303 1304  // retrieving the result1305  future<void> get_future();1306 1307  // setting the result1308  void set_value();1309  void set_exception(exception_ptr __p);1310 1311  // setting the result with deferred notification1312  void set_value_at_thread_exit();1313  void set_exception_at_thread_exit(exception_ptr __p);1314};1315 1316template <class _Alloc>1317promise<void>::promise(allocator_arg_t, const _Alloc& __a0) {1318  typedef __assoc_sub_state_alloc<_Alloc> _State;1319  typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;1320  typedef __allocator_destructor<_A2> _D2;1321  _A2 __a(__a0);1322  unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));1323  ::new ((void*)std::addressof(*__hold.get())) _State(__a0);1324  __state_ = std::addressof(*__hold.release());1325}1326 1327template <class _Rp>1328inline _LIBCPP_HIDE_FROM_ABI void swap(promise<_Rp>& __x, promise<_Rp>& __y) _NOEXCEPT {1329  __x.swap(__y);1330}1331 1332template <class _Rp, class _Alloc>1333struct _LIBCPP_TEMPLATE_VIS uses_allocator<promise<_Rp>, _Alloc> : public true_type {};1334 1335// packaged_task1336 1337template <class _Fp>1338class __packaged_task_base;1339 1340template <class _Rp, class... _ArgTypes>1341class __packaged_task_base<_Rp(_ArgTypes...)> {1342public:1343  _LIBCPP_HIDE_FROM_ABI __packaged_task_base() {}1344  __packaged_task_base(const __packaged_task_base&)            = delete;1345  __packaged_task_base& operator=(const __packaged_task_base&) = delete;1346  _LIBCPP_HIDE_FROM_ABI_VIRTUAL1347  virtual ~__packaged_task_base() {}1348  virtual void __move_to(__packaged_task_base*) _NOEXCEPT = 0;1349  virtual void destroy()                                  = 0;1350  virtual void destroy_deallocate()                       = 0;1351  virtual _Rp operator()(_ArgTypes&&...)                  = 0;1352};1353 1354template <class _FD, class _Alloc, class _FB>1355class __packaged_task_func;1356 1357template <class _Fp, class _Alloc, class _Rp, class... _ArgTypes>1358class __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)> : public __packaged_task_base<_Rp(_ArgTypes...)> {1359  __compressed_pair<_Fp, _Alloc> __f_;1360 1361public:1362  _LIBCPP_HIDE_FROM_ABI explicit __packaged_task_func(const _Fp& __f) : __f_(__f, __default_init_tag()) {}1363  _LIBCPP_HIDE_FROM_ABI explicit __packaged_task_func(_Fp&& __f) : __f_(std::move(__f), __default_init_tag()) {}1364  _LIBCPP_HIDE_FROM_ABI __packaged_task_func(const _Fp& __f, const _Alloc& __a) : __f_(__f, __a) {}1365  _LIBCPP_HIDE_FROM_ABI __packaged_task_func(_Fp&& __f, const _Alloc& __a) : __f_(std::move(__f), __a) {}1366  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void __move_to(__packaged_task_base<_Rp(_ArgTypes...)>*) _NOEXCEPT;1367  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void destroy();1368  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual void destroy_deallocate();1369  _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual _Rp operator()(_ArgTypes&&... __args);1370};1371 1372template <class _Fp, class _Alloc, class _Rp, class... _ArgTypes>1373void __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__move_to(1374    __packaged_task_base<_Rp(_ArgTypes...)>* __p) _NOEXCEPT {1375  ::new ((void*)__p) __packaged_task_func(std::move(__f_.first()), std::move(__f_.second()));1376}1377 1378template <class _Fp, class _Alloc, class _Rp, class... _ArgTypes>1379void __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy() {1380  __f_.~__compressed_pair<_Fp, _Alloc>();1381}1382 1383template <class _Fp, class _Alloc, class _Rp, class... _ArgTypes>1384void __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate() {1385  typedef typename __allocator_traits_rebind<_Alloc, __packaged_task_func>::type _Ap;1386  typedef allocator_traits<_Ap> _ATraits;1387  typedef pointer_traits<typename _ATraits::pointer> _PTraits;1388  _Ap __a(__f_.second());1389  __f_.~__compressed_pair<_Fp, _Alloc>();1390  __a.deallocate(_PTraits::pointer_to(*this), 1);1391}1392 1393template <class _Fp, class _Alloc, class _Rp, class... _ArgTypes>1394_Rp __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&&... __arg) {1395  return std::__invoke(__f_.first(), std::forward<_ArgTypes>(__arg)...);1396}1397 1398template <class _Callable>1399class __packaged_task_function;1400 1401template <class _Rp, class... _ArgTypes>1402class __packaged_task_function<_Rp(_ArgTypes...)> {1403  typedef __packaged_task_base<_Rp(_ArgTypes...)> __base;1404 1405  _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI __base* __get_buf() { return (__base*)&__buf_; }1406 1407  _LIBCPP_SUPPRESS_DEPRECATED_PUSH1408  typename aligned_storage<3 * sizeof(void*)>::type __buf_;1409  _LIBCPP_SUPPRESS_DEPRECATED_POP1410  __base* __f_;1411 1412public:1413  typedef _Rp result_type;1414 1415  // construct/copy/destroy:1416  _LIBCPP_HIDE_FROM_ABI __packaged_task_function() _NOEXCEPT : __f_(nullptr) {}1417  template <class _Fp>1418  _LIBCPP_HIDE_FROM_ABI __packaged_task_function(_Fp&& __f);1419  template <class _Fp, class _Alloc>1420  _LIBCPP_HIDE_FROM_ABI __packaged_task_function(allocator_arg_t, const _Alloc& __a, _Fp&& __f);1421 1422  _LIBCPP_HIDE_FROM_ABI __packaged_task_function(__packaged_task_function&&) _NOEXCEPT;1423  _LIBCPP_HIDE_FROM_ABI __packaged_task_function& operator=(__packaged_task_function&&) _NOEXCEPT;1424 1425  __packaged_task_function(const __packaged_task_function&)            = delete;1426  __packaged_task_function& operator=(const __packaged_task_function&) = delete;1427 1428  _LIBCPP_HIDE_FROM_ABI ~__packaged_task_function();1429 1430  _LIBCPP_HIDE_FROM_ABI void swap(__packaged_task_function&) _NOEXCEPT;1431 1432  _LIBCPP_HIDE_FROM_ABI _Rp operator()(_ArgTypes...) const;1433};1434 1435template <class _Rp, class... _ArgTypes>1436__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(__packaged_task_function&& __f) _NOEXCEPT {1437  if (__f.__f_ == nullptr)1438    __f_ = nullptr;1439  else if (__f.__f_ == __f.__get_buf()) {1440    __f.__f_->__move_to(__get_buf());1441    __f_ = (__base*)&__buf_;1442  } else {1443    __f_     = __f.__f_;1444    __f.__f_ = nullptr;1445  }1446}1447 1448template <class _Rp, class... _ArgTypes>1449template <class _Fp>1450__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(_Fp&& __f) : __f_(nullptr) {1451  typedef __libcpp_remove_reference_t<__decay_t<_Fp> > _FR;1452  typedef __packaged_task_func<_FR, allocator<_FR>, _Rp(_ArgTypes...)> _FF;1453  if (sizeof(_FF) <= sizeof(__buf_)) {1454    ::new ((void*)&__buf_) _FF(std::forward<_Fp>(__f));1455    __f_ = (__base*)&__buf_;1456  } else {1457    typedef allocator<_FF> _Ap;1458    _Ap __a;1459    typedef __allocator_destructor<_Ap> _Dp;1460    unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));1461    ::new ((void*)__hold.get()) _FF(std::forward<_Fp>(__f), allocator<_FR>(__a));1462    __f_ = __hold.release();1463  }1464}1465 1466template <class _Rp, class... _ArgTypes>1467template <class _Fp, class _Alloc>1468__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(allocator_arg_t, const _Alloc& __a0, _Fp&& __f)1469    : __f_(nullptr) {1470  typedef __libcpp_remove_reference_t<__decay_t<_Fp> > _FR;1471  typedef __packaged_task_func<_FR, _Alloc, _Rp(_ArgTypes...)> _FF;1472  if (sizeof(_FF) <= sizeof(__buf_)) {1473    __f_ = (__base*)&__buf_;1474    ::new ((void*)__f_) _FF(std::forward<_Fp>(__f));1475  } else {1476    typedef typename __allocator_traits_rebind<_Alloc, _FF>::type _Ap;1477    _Ap __a(__a0);1478    typedef __allocator_destructor<_Ap> _Dp;1479    unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));1480    ::new ((void*)std::addressof(*__hold.get())) _FF(std::forward<_Fp>(__f), _Alloc(__a));1481    __f_ = std::addressof(*__hold.release());1482  }1483}1484 1485template <class _Rp, class... _ArgTypes>1486__packaged_task_function<_Rp(_ArgTypes...)>&1487__packaged_task_function<_Rp(_ArgTypes...)>::operator=(__packaged_task_function&& __f) _NOEXCEPT {1488  if (__f_ == __get_buf())1489    __f_->destroy();1490  else if (__f_)1491    __f_->destroy_deallocate();1492  __f_ = nullptr;1493  if (__f.__f_ == nullptr)1494    __f_ = nullptr;1495  else if (__f.__f_ == __f.__get_buf()) {1496    __f.__f_->__move_to(__get_buf());1497    __f_ = __get_buf();1498  } else {1499    __f_     = __f.__f_;1500    __f.__f_ = nullptr;1501  }1502  return *this;1503}1504 1505template <class _Rp, class... _ArgTypes>1506__packaged_task_function<_Rp(_ArgTypes...)>::~__packaged_task_function() {1507  if (__f_ == __get_buf())1508    __f_->destroy();1509  else if (__f_)1510    __f_->destroy_deallocate();1511}1512 1513template <class _Rp, class... _ArgTypes>1514_LIBCPP_NO_CFI void __packaged_task_function<_Rp(_ArgTypes...)>::swap(__packaged_task_function& __f) _NOEXCEPT {1515  if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_) {1516    _LIBCPP_SUPPRESS_DEPRECATED_PUSH1517    typename aligned_storage<sizeof(__buf_)>::type __tempbuf;1518    _LIBCPP_SUPPRESS_DEPRECATED_POP1519    __base* __t = (__base*)&__tempbuf;1520    __f_->__move_to(__t);1521    __f_->destroy();1522    __f_ = nullptr;1523    __f.__f_->__move_to((__base*)&__buf_);1524    __f.__f_->destroy();1525    __f.__f_ = nullptr;1526    __f_     = (__base*)&__buf_;1527    __t->__move_to((__base*)&__f.__buf_);1528    __t->destroy();1529    __f.__f_ = (__base*)&__f.__buf_;1530  } else if (__f_ == (__base*)&__buf_) {1531    __f_->__move_to((__base*)&__f.__buf_);1532    __f_->destroy();1533    __f_     = __f.__f_;1534    __f.__f_ = (__base*)&__f.__buf_;1535  } else if (__f.__f_ == (__base*)&__f.__buf_) {1536    __f.__f_->__move_to((__base*)&__buf_);1537    __f.__f_->destroy();1538    __f.__f_ = __f_;1539    __f_     = (__base*)&__buf_;1540  } else1541    std::swap(__f_, __f.__f_);1542}1543 1544template <class _Rp, class... _ArgTypes>1545inline _Rp __packaged_task_function<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __arg) const {1546  return (*__f_)(std::forward<_ArgTypes>(__arg)...);1547}1548 1549template <class _Rp, class... _ArgTypes>1550class _LIBCPP_TEMPLATE_VIS packaged_task<_Rp(_ArgTypes...)> {1551public:1552  typedef _Rp result_type; // extension1553 1554private:1555  __packaged_task_function<result_type(_ArgTypes...)> __f_;1556  promise<result_type> __p_;1557 1558public:1559  // construction and destruction1560  _LIBCPP_HIDE_FROM_ABI packaged_task() _NOEXCEPT : __p_(nullptr) {}1561 1562  template <class _Fp, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, packaged_task>::value, int> = 0>1563  _LIBCPP_HIDE_FROM_ABI explicit packaged_task(_Fp&& __f) : __f_(std::forward<_Fp>(__f)) {}1564 1565  template <class _Fp, class _Allocator, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, packaged_task>::value, int> = 0>1566  _LIBCPP_HIDE_FROM_ABI packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)1567      : __f_(allocator_arg_t(), __a, std::forward<_Fp>(__f)), __p_(allocator_arg_t(), __a) {}1568  // ~packaged_task() = default;1569 1570  // no copy1571  packaged_task(const packaged_task&)            = delete;1572  packaged_task& operator=(const packaged_task&) = delete;1573 1574  // move support1575  _LIBCPP_HIDE_FROM_ABI packaged_task(packaged_task&& __other) _NOEXCEPT1576      : __f_(std::move(__other.__f_)),1577        __p_(std::move(__other.__p_)) {}1578  _LIBCPP_HIDE_FROM_ABI packaged_task& operator=(packaged_task&& __other) _NOEXCEPT {1579    __f_ = std::move(__other.__f_);1580    __p_ = std::move(__other.__p_);1581    return *this;1582  }1583  _LIBCPP_HIDE_FROM_ABI void swap(packaged_task& __other) _NOEXCEPT {1584    __f_.swap(__other.__f_);1585    __p_.swap(__other.__p_);1586  }1587 1588  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __p_.__state_ != nullptr; }1589 1590  // result retrieval1591  _LIBCPP_HIDE_FROM_ABI future<result_type> get_future() { return __p_.get_future(); }1592 1593  // execution1594  _LIBCPP_HIDE_FROM_ABI void operator()(_ArgTypes... __args);1595  _LIBCPP_HIDE_FROM_ABI void make_ready_at_thread_exit(_ArgTypes... __args);1596 1597  _LIBCPP_HIDE_FROM_ABI void reset();1598};1599 1600template <class _Rp, class... _ArgTypes>1601void packaged_task<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __args) {1602  if (__p_.__state_ == nullptr)1603    __throw_future_error(future_errc::no_state);1604  if (__p_.__state_->__has_value())1605    __throw_future_error(future_errc::promise_already_satisfied);1606#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1607  try {1608#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1609    __p_.set_value(__f_(std::forward<_ArgTypes>(__args)...));1610#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1611  } catch (...) {1612    __p_.set_exception(current_exception());1613  }1614#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1615}1616 1617template <class _Rp, class... _ArgTypes>1618void packaged_task<_Rp(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args) {1619  if (__p_.__state_ == nullptr)1620    __throw_future_error(future_errc::no_state);1621  if (__p_.__state_->__has_value())1622    __throw_future_error(future_errc::promise_already_satisfied);1623#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1624  try {1625#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1626    __p_.set_value_at_thread_exit(__f_(std::forward<_ArgTypes>(__args)...));1627#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1628  } catch (...) {1629    __p_.set_exception_at_thread_exit(current_exception());1630  }1631#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1632}1633 1634template <class _Rp, class... _ArgTypes>1635void packaged_task<_Rp(_ArgTypes...)>::reset() {1636  if (!valid())1637    __throw_future_error(future_errc::no_state);1638  __p_ = promise<result_type>();1639}1640 1641template <class... _ArgTypes>1642class _LIBCPP_TEMPLATE_VIS packaged_task<void(_ArgTypes...)> {1643public:1644  typedef void result_type; // extension1645 1646private:1647  __packaged_task_function<result_type(_ArgTypes...)> __f_;1648  promise<result_type> __p_;1649 1650public:1651  // construction and destruction1652  _LIBCPP_HIDE_FROM_ABI packaged_task() _NOEXCEPT : __p_(nullptr) {}1653  template <class _Fp, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, packaged_task>::value, int> = 0>1654  _LIBCPP_HIDE_FROM_ABI explicit packaged_task(_Fp&& __f) : __f_(std::forward<_Fp>(__f)) {}1655  template <class _Fp, class _Allocator, __enable_if_t<!is_same<__remove_cvref_t<_Fp>, packaged_task>::value, int> = 0>1656  _LIBCPP_HIDE_FROM_ABI packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)1657      : __f_(allocator_arg_t(), __a, std::forward<_Fp>(__f)), __p_(allocator_arg_t(), __a) {}1658  // ~packaged_task() = default;1659 1660  // no copy1661  packaged_task(const packaged_task&)            = delete;1662  packaged_task& operator=(const packaged_task&) = delete;1663 1664  // move support1665  _LIBCPP_HIDE_FROM_ABI packaged_task(packaged_task&& __other) _NOEXCEPT1666      : __f_(std::move(__other.__f_)),1667        __p_(std::move(__other.__p_)) {}1668  _LIBCPP_HIDE_FROM_ABI packaged_task& operator=(packaged_task&& __other) _NOEXCEPT {1669    __f_ = std::move(__other.__f_);1670    __p_ = std::move(__other.__p_);1671    return *this;1672  }1673  _LIBCPP_HIDE_FROM_ABI void swap(packaged_task& __other) _NOEXCEPT {1674    __f_.swap(__other.__f_);1675    __p_.swap(__other.__p_);1676  }1677 1678  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __p_.__state_ != nullptr; }1679 1680  // result retrieval1681  _LIBCPP_HIDE_FROM_ABI future<result_type> get_future() { return __p_.get_future(); }1682 1683  // execution1684  _LIBCPP_HIDE_FROM_ABI void operator()(_ArgTypes... __args);1685  _LIBCPP_HIDE_FROM_ABI void make_ready_at_thread_exit(_ArgTypes... __args);1686 1687  _LIBCPP_HIDE_FROM_ABI void reset();1688};1689 1690template <class... _ArgTypes>1691void packaged_task<void(_ArgTypes...)>::operator()(_ArgTypes... __args) {1692  if (__p_.__state_ == nullptr)1693    __throw_future_error(future_errc::no_state);1694  if (__p_.__state_->__has_value())1695    __throw_future_error(future_errc::promise_already_satisfied);1696#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1697  try {1698#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1699    __f_(std::forward<_ArgTypes>(__args)...);1700    __p_.set_value();1701#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1702  } catch (...) {1703    __p_.set_exception(current_exception());1704  }1705#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1706}1707 1708template <class... _ArgTypes>1709void packaged_task<void(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args) {1710  if (__p_.__state_ == nullptr)1711    __throw_future_error(future_errc::no_state);1712  if (__p_.__state_->__has_value())1713    __throw_future_error(future_errc::promise_already_satisfied);1714#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1715  try {1716#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1717    __f_(std::forward<_ArgTypes>(__args)...);1718    __p_.set_value_at_thread_exit();1719#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS1720  } catch (...) {1721    __p_.set_exception_at_thread_exit(current_exception());1722  }1723#  endif // _LIBCPP_HAS_NO_EXCEPTIONS1724}1725 1726template <class... _ArgTypes>1727void packaged_task<void(_ArgTypes...)>::reset() {1728  if (!valid())1729    __throw_future_error(future_errc::no_state);1730  __p_ = promise<result_type>();1731}1732 1733template <class _Rp, class... _ArgTypes>1734inline _LIBCPP_HIDE_FROM_ABI void1735swap(packaged_task<_Rp(_ArgTypes...)>& __x, packaged_task<_Rp(_ArgTypes...)>& __y) _NOEXCEPT {1736  __x.swap(__y);1737}1738 1739template <class _Callable, class _Alloc>1740struct _LIBCPP_TEMPLATE_VIS uses_allocator<packaged_task<_Callable>, _Alloc> : public true_type {};1741 1742template <class _Rp, class _Fp>1743_LIBCPP_HIDE_FROM_ABI future<_Rp> __make_deferred_assoc_state(_Fp&& __f) {1744  unique_ptr<__deferred_assoc_state<_Rp, _Fp>, __release_shared_count> __h(1745      new __deferred_assoc_state<_Rp, _Fp>(std::forward<_Fp>(__f)));1746  return future<_Rp>(__h.get());1747}1748 1749template <class _Rp, class _Fp>1750_LIBCPP_HIDE_FROM_ABI future<_Rp> __make_async_assoc_state(_Fp&& __f) {1751  unique_ptr<__async_assoc_state<_Rp, _Fp>, __release_shared_count> __h(1752      new __async_assoc_state<_Rp, _Fp>(std::forward<_Fp>(__f)));1753  std::thread(&__async_assoc_state<_Rp, _Fp>::__execute, __h.get()).detach();1754  return future<_Rp>(__h.get());1755}1756 1757// shared_future1758 1759template <class _Rp>1760class _LIBCPP_TEMPLATE_VIS shared_future {1761  __assoc_state<_Rp>* __state_;1762 1763public:1764  _LIBCPP_HIDE_FROM_ABI shared_future() _NOEXCEPT : __state_(nullptr) {}1765  _LIBCPP_HIDE_FROM_ABI shared_future(const shared_future& __rhs) _NOEXCEPT : __state_(__rhs.__state_) {1766    if (__state_)1767      __state_->__add_shared();1768  }1769  _LIBCPP_HIDE_FROM_ABI shared_future(future<_Rp>&& __f) _NOEXCEPT : __state_(__f.__state_) { __f.__state_ = nullptr; }1770  _LIBCPP_HIDE_FROM_ABI shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) {1771    __rhs.__state_ = nullptr;1772  }1773  _LIBCPP_HIDE_FROM_ABI ~shared_future();1774  _LIBCPP_HIDE_FROM_ABI shared_future& operator=(const shared_future& __rhs) _NOEXCEPT;1775  _LIBCPP_HIDE_FROM_ABI shared_future& operator=(shared_future&& __rhs) _NOEXCEPT {1776    shared_future(std::move(__rhs)).swap(*this);1777    return *this;1778  }1779 1780  // retrieving the value1781  _LIBCPP_HIDE_FROM_ABI const _Rp& get() const { return __state_->copy(); }1782 1783  _LIBCPP_HIDE_FROM_ABI void swap(shared_future& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1784 1785  // functions to check state1786  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __state_ != nullptr; }1787 1788  _LIBCPP_HIDE_FROM_ABI void wait() const { __state_->wait(); }1789  template <class _Rep, class _Period>1790  _LIBCPP_HIDE_FROM_ABI future_status wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {1791    return __state_->wait_for(__rel_time);1792  }1793  template <class _Clock, class _Duration>1794  _LIBCPP_HIDE_FROM_ABI future_status wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {1795    return __state_->wait_until(__abs_time);1796  }1797};1798 1799template <class _Rp>1800shared_future<_Rp>::~shared_future() {1801  if (__state_)1802    __state_->__release_shared();1803}1804 1805template <class _Rp>1806shared_future<_Rp>& shared_future<_Rp>::operator=(const shared_future& __rhs) _NOEXCEPT {1807  if (__rhs.__state_)1808    __rhs.__state_->__add_shared();1809  if (__state_)1810    __state_->__release_shared();1811  __state_ = __rhs.__state_;1812  return *this;1813}1814 1815template <class _Rp>1816class _LIBCPP_TEMPLATE_VIS shared_future<_Rp&> {1817  __assoc_state<_Rp&>* __state_;1818 1819public:1820  _LIBCPP_HIDE_FROM_ABI shared_future() _NOEXCEPT : __state_(nullptr) {}1821  _LIBCPP_HIDE_FROM_ABI shared_future(const shared_future& __rhs) : __state_(__rhs.__state_) {1822    if (__state_)1823      __state_->__add_shared();1824  }1825  _LIBCPP_HIDE_FROM_ABI shared_future(future<_Rp&>&& __f) _NOEXCEPT : __state_(__f.__state_) { __f.__state_ = nullptr; }1826  _LIBCPP_HIDE_FROM_ABI shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) {1827    __rhs.__state_ = nullptr;1828  }1829  _LIBCPP_HIDE_FROM_ABI ~shared_future();1830  _LIBCPP_HIDE_FROM_ABI shared_future& operator=(const shared_future& __rhs);1831  _LIBCPP_HIDE_FROM_ABI shared_future& operator=(shared_future&& __rhs) _NOEXCEPT {1832    shared_future(std::move(__rhs)).swap(*this);1833    return *this;1834  }1835 1836  // retrieving the value1837  _LIBCPP_HIDE_FROM_ABI _Rp& get() const { return __state_->copy(); }1838 1839  _LIBCPP_HIDE_FROM_ABI void swap(shared_future& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1840 1841  // functions to check state1842  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __state_ != nullptr; }1843 1844  _LIBCPP_HIDE_FROM_ABI void wait() const { __state_->wait(); }1845  template <class _Rep, class _Period>1846  _LIBCPP_HIDE_FROM_ABI future_status wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {1847    return __state_->wait_for(__rel_time);1848  }1849  template <class _Clock, class _Duration>1850  _LIBCPP_HIDE_FROM_ABI future_status wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {1851    return __state_->wait_until(__abs_time);1852  }1853};1854 1855template <class _Rp>1856shared_future<_Rp&>::~shared_future() {1857  if (__state_)1858    __state_->__release_shared();1859}1860 1861template <class _Rp>1862shared_future<_Rp&>& shared_future<_Rp&>::operator=(const shared_future& __rhs) {1863  if (__rhs.__state_)1864    __rhs.__state_->__add_shared();1865  if (__state_)1866    __state_->__release_shared();1867  __state_ = __rhs.__state_;1868  return *this;1869}1870 1871template <>1872class _LIBCPP_EXPORTED_FROM_ABI shared_future<void> {1873  __assoc_sub_state* __state_;1874 1875public:1876  _LIBCPP_HIDE_FROM_ABI shared_future() _NOEXCEPT : __state_(nullptr) {}1877  _LIBCPP_HIDE_FROM_ABI shared_future(const shared_future& __rhs) : __state_(__rhs.__state_) {1878    if (__state_)1879      __state_->__add_shared();1880  }1881  _LIBCPP_HIDE_FROM_ABI shared_future(future<void>&& __f) _NOEXCEPT : __state_(__f.__state_) { __f.__state_ = nullptr; }1882  _LIBCPP_HIDE_FROM_ABI shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_) {1883    __rhs.__state_ = nullptr;1884  }1885  ~shared_future();1886  shared_future& operator=(const shared_future& __rhs);1887  _LIBCPP_HIDE_FROM_ABI shared_future& operator=(shared_future&& __rhs) _NOEXCEPT {1888    shared_future(std::move(__rhs)).swap(*this);1889    return *this;1890  }1891 1892  // retrieving the value1893  _LIBCPP_HIDE_FROM_ABI void get() const { __state_->copy(); }1894 1895  _LIBCPP_HIDE_FROM_ABI void swap(shared_future& __rhs) _NOEXCEPT { std::swap(__state_, __rhs.__state_); }1896 1897  // functions to check state1898  _LIBCPP_HIDE_FROM_ABI bool valid() const _NOEXCEPT { return __state_ != nullptr; }1899 1900  _LIBCPP_HIDE_FROM_ABI void wait() const { __state_->wait(); }1901  template <class _Rep, class _Period>1902  _LIBCPP_HIDE_FROM_ABI future_status wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const {1903    return __state_->wait_for(__rel_time);1904  }1905  template <class _Clock, class _Duration>1906  _LIBCPP_HIDE_FROM_ABI future_status wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const {1907    return __state_->wait_until(__abs_time);1908  }1909};1910 1911template <class _Rp>1912inline _LIBCPP_HIDE_FROM_ABI void swap(shared_future<_Rp>& __x, shared_future<_Rp>& __y) _NOEXCEPT {1913  __x.swap(__y);1914}1915 1916template <class _Rp>1917inline shared_future<_Rp> future<_Rp>::share() _NOEXCEPT {1918  return shared_future<_Rp>(std::move(*this));1919}1920 1921template <class _Rp>1922inline shared_future<_Rp&> future<_Rp&>::share() _NOEXCEPT {1923  return shared_future<_Rp&>(std::move(*this));1924}1925 1926inline shared_future<void> future<void>::share() _NOEXCEPT { return shared_future<void>(std::move(*this)); }1927 1928_LIBCPP_END_NAMESPACE_STD1929 1930_LIBCPP_POP_MACROS1931 1932#endif // !defined(_LIBCPP_HAS_NO_THREADS)1933 1934#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES)1935#  include <__cxx03/chrono>1936#endif1937 1938#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES)1939#  include <__cxx03/atomic>1940#  include <__cxx03/cstdlib>1941#  include <__cxx03/exception>1942#  include <__cxx03/iosfwd>1943#  include <__cxx03/system_error>1944#endif1945 1946#endif // _LIBCPP___CXX03_FUTURE1947