94 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// UNSUPPORTED: no-threads10// UNSUPPORTED: c++03, c++11, c++14, c++1711 12// [[nodiscard]] bool stop_possible() const noexcept;13// Returns: false if:14// - *this does not have ownership of a stop state, or15// - a stop request was not made and there are no associated stop_source objects;16// otherwise, true.17 18#include <cassert>19#include <concepts>20#include <optional>21#include <stop_token>22#include <type_traits>23 24#include "make_test_thread.h"25#include "test_macros.h"26 27template <class T>28concept IsStopPossibleNoexcept = requires(const T& t) {29 { t.stop_possible() } noexcept;30};31 32static_assert(IsStopPossibleNoexcept<std::stop_token>);33 34int main(int, char**) {35 // no state36 {37 const std::stop_token st;38 assert(!st.stop_possible());39 }40 41 // a stop request was not made and there are no associated stop_source objects42 {43 std::optional<std::stop_source> ss{std::in_place};44 const auto st = ss->get_token();45 ss.reset();46 47 assert(!st.stop_possible());48 }49 50 // a stop request was not made, but there is an associated stop_source objects51 {52 std::stop_source ss;53 const auto st = ss.get_token();54 assert(st.stop_possible());55 }56 57 // a stop request was made and there are no associated stop_source objects58 {59 std::optional<std::stop_source> ss{std::in_place};60 const auto st = ss->get_token();61 ss->request_stop();62 ss.reset();63 64 assert(st.stop_possible());65 }66 67 // a stop request was made and there is an associated stop_source objects68 {69 std::stop_source ss;70 const auto st = ss.get_token();71 ss.request_stop();72 assert(st.stop_possible());73 }74 75 // a stop request was made on a different thread and76 // there are no associated stop_source objects77 {78 std::optional<std::stop_source> ss{std::in_place};79 const auto st = ss->get_token();80 81 std::thread t = support::make_test_thread([&]() {82 ss->request_stop();83 ss.reset();84 });85 86 assert(st.stop_possible());87 t.join();88 assert(st.stop_possible());89 90 }91 92 return 0;93}94