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___THREAD_JTHREAD_H 11 #define _LIBCPP___THREAD_JTHREAD_H 12 13 #include <__config> 14 #include <__functional/invoke.h> 15 #include <__stop_token/stop_source.h> 16 #include <__stop_token/stop_token.h> 17 #include <__thread/support.h> 18 #include <__thread/thread.h> 19 #include <__type_traits/decay.h> 20 #include <__type_traits/is_constructible.h> 21 #include <__type_traits/is_same.h> 22 #include <__type_traits/remove_cvref.h> 23 #include <__utility/forward.h> 24 #include <__utility/move.h> 25 26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 27 # pragma GCC system_header 28 #endif 29 30 _LIBCPP_PUSH_MACROS 31 #include <__undef_macros> 32 33 #if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 34 35 _LIBCPP_BEGIN_NAMESPACE_STD 36 37 class _LIBCPP_AVAILABILITY_SYNC jthread { 38 public: 39 // types 40 using id = thread::id; 41 using native_handle_type = thread::native_handle_type; 42 43 // [thread.jthread.cons], constructors, move, and assignment 44 _LIBCPP_HIDE_FROM_ABI jthread() noexcept : __stop_source_(std::nostopstate) {} 45 46 template <class _Fun, class... _Args> 47 _LIBCPP_HIDE_FROM_ABI explicit jthread(_Fun&& __fun, _Args&&... __args) 48 requires(!std::is_same_v<remove_cvref_t<_Fun>, jthread>) 49 : __stop_source_(), 50 __thread_(__init_thread(__stop_source_, std::forward<_Fun>(__fun), std::forward<_Args>(__args)...)) { 51 static_assert(is_constructible_v<decay_t<_Fun>, _Fun>); 52 static_assert((is_constructible_v<decay_t<_Args>, _Args> && ...)); 53 static_assert(is_invocable_v<decay_t<_Fun>, decay_t<_Args>...> || 54 is_invocable_v<decay_t<_Fun>, stop_token, decay_t<_Args>...>); 55 } 56 57 _LIBCPP_HIDE_FROM_ABI ~jthread() { 58 if (joinable()) { 59 request_stop(); 60 join(); 61 } 62 } 63 64 jthread(const jthread&) = delete; 65 66 _LIBCPP_HIDE_FROM_ABI jthread(jthread&&) noexcept = default; 67 68 jthread& operator=(const jthread&) = delete; 69 70 _LIBCPP_HIDE_FROM_ABI jthread& operator=(jthread&& __other) noexcept { 71 if (this != &__other) { 72 if (joinable()) { 73 request_stop(); 74 join(); 75 } 76 __stop_source_ = std::move(__other.__stop_source_); 77 __thread_ = std::move(__other.__thread_); 78 } 79 80 return *this; 81 } 82 83 // [thread.jthread.mem], members 84 _LIBCPP_HIDE_FROM_ABI void swap(jthread& __other) noexcept { 85 std::swap(__stop_source_, __other.__stop_source_); 86 std::swap(__thread_, __other.__thread_); 87 } 88 89 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool joinable() const noexcept { return get_id() != id(); } 90 91 _LIBCPP_HIDE_FROM_ABI void join() { __thread_.join(); } 92 93 _LIBCPP_HIDE_FROM_ABI void detach() { __thread_.detach(); } 94 95 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI id get_id() const noexcept { return __thread_.get_id(); } 96 97 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return __thread_.native_handle(); } 98 99 // [thread.jthread.stop], stop token handling 100 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI stop_source get_stop_source() noexcept { return __stop_source_; } 101 102 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI stop_token get_stop_token() const noexcept { return __stop_source_.get_token(); } 103 104 _LIBCPP_HIDE_FROM_ABI bool request_stop() noexcept { return __stop_source_.request_stop(); } 105 106 // [thread.jthread.special], specialized algorithms 107 _LIBCPP_HIDE_FROM_ABI friend void swap(jthread& __lhs, jthread& __rhs) noexcept { __lhs.swap(__rhs); } 108 109 // [thread.jthread.static], static members 110 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static unsigned int hardware_concurrency() noexcept { 111 return thread::hardware_concurrency(); 112 } 113 114 private: 115 template <class _Fun, class... _Args> 116 _LIBCPP_HIDE_FROM_ABI static thread __init_thread(const stop_source& __ss, _Fun&& __fun, _Args&&... __args) { 117 if constexpr (is_invocable_v<decay_t<_Fun>, stop_token, decay_t<_Args>...>) { 118 return thread(std::forward<_Fun>(__fun), __ss.get_token(), std::forward<_Args>(__args)...); 119 } else { 120 return thread(std::forward<_Fun>(__fun), std::forward<_Args>(__args)...); 121 } 122 } 123 124 stop_source __stop_source_; 125 thread __thread_; 126 }; 127 128 _LIBCPP_END_NAMESPACE_STD 129 130 #endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_STOP_TOKEN) 131 132 _LIBCPP_POP_MACROS 133 134 #endif // _LIBCPP___THREAD_JTHREAD_H 135