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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___THREAD_JTHREAD_H11#define _LIBCPP___THREAD_JTHREAD_H12 13#include <__config>14#include <__stop_token/stop_source.h>15#include <__stop_token/stop_token.h>16#include <__thread/id.h>17#include <__thread/support.h>18#include <__thread/thread.h>19#include <__type_traits/decay.h>20#include <__type_traits/invoke.h>21#include <__type_traits/is_constructible.h>22#include <__type_traits/is_same.h>23#include <__type_traits/remove_cvref.h>24#include <__utility/forward.h>25#include <__utility/move.h>26#include <__utility/swap.h>27 28#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)29# pragma GCC system_header30#endif31 32_LIBCPP_PUSH_MACROS33#include <__undef_macros>34 35#if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_THREADS36 37_LIBCPP_BEGIN_NAMESPACE_STD38 39class jthread {40public:41 // types42 using id = thread::id;43 using native_handle_type = thread::native_handle_type;44 45 // [thread.jthread.cons], constructors, move, and assignment46 _LIBCPP_HIDE_FROM_ABI jthread() noexcept : __stop_source_(std::nostopstate) {}47 48 template <class _Fun, class... _Args>49 _LIBCPP_HIDE_FROM_ABI explicit jthread(_Fun&& __fun, _Args&&... __args)50 requires(!std::is_same_v<remove_cvref_t<_Fun>, jthread>)51 : __stop_source_(),52 __thread_(__init_thread(__stop_source_, std::forward<_Fun>(__fun), std::forward<_Args>(__args)...)) {53 static_assert(is_constructible_v<decay_t<_Fun>, _Fun>);54 static_assert((is_constructible_v<decay_t<_Args>, _Args> && ...));55 static_assert(is_invocable_v<decay_t<_Fun>, decay_t<_Args>...> ||56 is_invocable_v<decay_t<_Fun>, stop_token, decay_t<_Args>...>);57 }58 59 _LIBCPP_HIDE_FROM_ABI ~jthread() {60 if (joinable()) {61 request_stop();62 join();63 }64 }65 66 jthread(const jthread&) = delete;67 68 _LIBCPP_HIDE_FROM_ABI jthread(jthread&&) noexcept = default;69 70 jthread& operator=(const jthread&) = delete;71 72 _LIBCPP_HIDE_FROM_ABI jthread& operator=(jthread&& __other) noexcept {73 if (this != &__other) {74 if (joinable()) {75 request_stop();76 join();77 }78 __stop_source_ = std::move(__other.__stop_source_);79 __thread_ = std::move(__other.__thread_);80 }81 82 return *this;83 }84 85 // [thread.jthread.mem], members86 _LIBCPP_HIDE_FROM_ABI void swap(jthread& __other) noexcept {87 std::swap(__stop_source_, __other.__stop_source_);88 std::swap(__thread_, __other.__thread_);89 }90 91 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool joinable() const noexcept { return get_id() != id(); }92 93 _LIBCPP_HIDE_FROM_ABI void join() { __thread_.join(); }94 95 _LIBCPP_HIDE_FROM_ABI void detach() { __thread_.detach(); }96 97 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI id get_id() const noexcept { return __thread_.get_id(); }98 99 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return __thread_.native_handle(); }100 101 // [thread.jthread.stop], stop token handling102 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI stop_source get_stop_source() noexcept { return __stop_source_; }103 104 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI stop_token get_stop_token() const noexcept { return __stop_source_.get_token(); }105 106 _LIBCPP_HIDE_FROM_ABI bool request_stop() noexcept { return __stop_source_.request_stop(); }107 108 // [thread.jthread.special], specialized algorithms109 _LIBCPP_HIDE_FROM_ABI friend void swap(jthread& __lhs, jthread& __rhs) noexcept { __lhs.swap(__rhs); }110 111 // [thread.jthread.static], static members112 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static unsigned int hardware_concurrency() noexcept {113 return thread::hardware_concurrency();114 }115 116private:117 template <class _Fun, class... _Args>118 _LIBCPP_HIDE_FROM_ABI static thread __init_thread(const stop_source& __ss, _Fun&& __fun, _Args&&... __args) {119 if constexpr (is_invocable_v<decay_t<_Fun>, stop_token, decay_t<_Args>...>) {120 return thread(std::forward<_Fun>(__fun), __ss.get_token(), std::forward<_Args>(__args)...);121 } else {122 return thread(std::forward<_Fun>(__fun), std::forward<_Args>(__args)...);123 }124 }125 126 stop_source __stop_source_;127 thread __thread_;128};129 130_LIBCPP_END_NAMESPACE_STD131 132#endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_THREADS133 134_LIBCPP_POP_MACROS135 136#endif // _LIBCPP___THREAD_JTHREAD_H137