1*b77e50e6SHui //===----------------------------------------------------------------------===// 2*b77e50e6SHui // 3*b77e50e6SHui // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*b77e50e6SHui // See https://llvm.org/LICENSE.txt for license information. 5*b77e50e6SHui // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*b77e50e6SHui // 7*b77e50e6SHui //===----------------------------------------------------------------------===// 8*b77e50e6SHui // 9*b77e50e6SHui // UNSUPPORTED: no-threads 10*b77e50e6SHui // UNSUPPORTED: c++03, c++11, c++14, c++17 11*b77e50e6SHui // XFAIL: availability-synchronization_library-missing 12*b77e50e6SHui 13*b77e50e6SHui // [[nodiscard]] bool stop_possible() const noexcept; 14*b77e50e6SHui // Returns: false if: 15*b77e50e6SHui // - *this does not have ownership of a stop state, or 16*b77e50e6SHui // - a stop request was not made and there are no associated stop_source objects; 17*b77e50e6SHui // otherwise, true. 18*b77e50e6SHui 19*b77e50e6SHui #include <cassert> 20*b77e50e6SHui #include <concepts> 21*b77e50e6SHui #include <optional> 22*b77e50e6SHui #include <stop_token> 23*b77e50e6SHui #include <type_traits> 24*b77e50e6SHui 25*b77e50e6SHui #include "make_test_thread.h" 26*b77e50e6SHui #include "test_macros.h" 27*b77e50e6SHui 28*b77e50e6SHui template <class T> 29*b77e50e6SHui concept IsStopPossibleNoexcept = requires(const T& t) { 30*b77e50e6SHui { t.stop_possible() } noexcept; 31*b77e50e6SHui }; 32*b77e50e6SHui 33*b77e50e6SHui static_assert(IsStopPossibleNoexcept<std::stop_token>); 34*b77e50e6SHui 35*b77e50e6SHui int main(int, char**) { 36*b77e50e6SHui // no state 37*b77e50e6SHui { 38*b77e50e6SHui const std::stop_token st; 39*b77e50e6SHui assert(!st.stop_possible()); 40*b77e50e6SHui } 41*b77e50e6SHui 42*b77e50e6SHui // a stop request was not made and there are no associated stop_source objects 43*b77e50e6SHui { 44*b77e50e6SHui std::optional<std::stop_source> ss{std::in_place}; 45*b77e50e6SHui const auto st = ss->get_token(); 46*b77e50e6SHui ss.reset(); 47*b77e50e6SHui 48*b77e50e6SHui assert(!st.stop_possible()); 49*b77e50e6SHui } 50*b77e50e6SHui 51*b77e50e6SHui // a stop request was not made, but there is an associated stop_source objects 52*b77e50e6SHui { 53*b77e50e6SHui std::stop_source ss; 54*b77e50e6SHui const auto st = ss.get_token(); 55*b77e50e6SHui assert(st.stop_possible()); 56*b77e50e6SHui } 57*b77e50e6SHui 58*b77e50e6SHui // a stop request was made and there are no associated stop_source objects 59*b77e50e6SHui { 60*b77e50e6SHui std::optional<std::stop_source> ss{std::in_place}; 61*b77e50e6SHui const auto st = ss->get_token(); 62*b77e50e6SHui ss->request_stop(); 63*b77e50e6SHui ss.reset(); 64*b77e50e6SHui 65*b77e50e6SHui assert(st.stop_possible()); 66*b77e50e6SHui } 67*b77e50e6SHui 68*b77e50e6SHui // a stop request was made and there is an associated stop_source objects 69*b77e50e6SHui { 70*b77e50e6SHui std::stop_source ss; 71*b77e50e6SHui const auto st = ss.get_token(); 72*b77e50e6SHui ss.request_stop(); 73*b77e50e6SHui assert(st.stop_possible()); 74*b77e50e6SHui } 75*b77e50e6SHui 76*b77e50e6SHui // a stop request was made on a different thread and 77*b77e50e6SHui // there are no associated stop_source objects 78*b77e50e6SHui { 79*b77e50e6SHui std::optional<std::stop_source> ss{std::in_place}; 80*b77e50e6SHui const auto st = ss->get_token(); 81*b77e50e6SHui 82*b77e50e6SHui std::thread t = support::make_test_thread([&]() { 83*b77e50e6SHui ss->request_stop(); 84*b77e50e6SHui ss.reset(); 85*b77e50e6SHui }); 86*b77e50e6SHui 87*b77e50e6SHui assert(st.stop_possible()); 88*b77e50e6SHui t.join(); 89*b77e50e6SHui assert(st.stop_possible()); 90*b77e50e6SHui 91*b77e50e6SHui } 92*b77e50e6SHui 93*b77e50e6SHui return 0; 94*b77e50e6SHui } 95