libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_token_pred.pass.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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // UNSUPPORTED: no-threads
  10 // UNSUPPORTED: c++03, c++11, c++14, c++17
  11 // UNSUPPORTED: libcpp-has-no-experimental-stop_token
  12 // XFAIL: availability-synchronization_library-missing
  13
  14 // <condition_variable>
  15
  16 // class condition_variable_any;
  17
  18 // template<class Lock, class Predicate>
  19 //   bool wait(Lock& lock, stop_token stoken, Predicate pred);
  20
  21 #include <cassert>
  22 #include <concepts>
  23 #include <condition_variable>
  24 #include <functional>
  25 #include <mutex>
  26 #include <shared_mutex>
  27 #include <stop_token>
  28 #include <thread>
  29
  30 #include "make_test_thread.h"
  31 #include "test_macros.h"
  32
  33 template <class Mutex, class Lock>
  34 void test() {
  35   // stop_requested before hand
  36   {
  37     std::stop_source ss;
  38     std::condition_variable_any cv;
  39     Mutex mutex;
  40     Lock lock{mutex};
  41     ss.request_stop();
  42
  43     // [Note 1: The returned value indicates whether the predicate evaluated to true regardless of whether there was a stop request.]
  44     std::same_as<bool> auto r1 = cv.wait(lock, ss.get_token(), []() { return false; });
  45     assert(!r1);
  46
  47     std::same_as<bool> auto r2 = cv.wait(lock, ss.get_token(), []() { return true; });
  48     assert(r2);
  49
  50     // Postconditions: lock is locked by the calling thread.
  51     assert(lock.owns_lock());
  52   }
  53
  54   // no stop request
  55   {
  56     std::stop_source ss;
  57     std::condition_variable_any cv;
  58     Mutex mutex;
  59     Lock lock{mutex};
  60     std::same_as<bool> auto r1 = cv.wait(lock, ss.get_token(), []() { return true; });
  61     assert(r1);
  62
  63     bool flag   = false;
  64     auto thread = support::make_test_thread([&]() {
  65       std::this_thread::sleep_for(std::chrono::milliseconds(2));
  66       Lock lock2{mutex};
  67       flag = true;
  68       cv.notify_all();
  69     });
  70
  71     std::same_as<bool> auto r2 = cv.wait(lock, ss.get_token(), [&]() { return flag; });
  72     assert(flag);
  73     assert(r2);
  74     thread.join();
  75
  76     assert(lock.owns_lock());
  77   }
  78
  79   // stop request comes while waiting
  80   {
  81     std::stop_source ss;
  82     std::condition_variable_any cv;
  83     Mutex mutex;
  84     Lock lock{mutex};
  85
  86     std::atomic_bool start = false;
  87     std::atomic_bool done  = false;
  88     auto thread            = support::make_test_thread([&]() {
  89       start.wait(false);
  90       ss.request_stop();
  91
  92       while (!done) {
  93         cv.notify_all();
  94         std::this_thread::sleep_for(std::chrono::milliseconds(2));
  95       }
  96     });
  97
  98     std::same_as<bool> auto r = cv.wait(lock, ss.get_token(), [&]() {
  99       start.store(true);
 100       start.notify_all();
 101       return false;
 102     });
 103     assert(!r);
 104     done = true;
 105     thread.join();
 106
 107     assert(lock.owns_lock());
 108   }
 109
 110   // #76807 Hangs in std::condition_variable_any when used with std::stop_token
 111   {
 112     class MyThread {
 113     public:
 114       MyThread() {
 115         thread_ = support::make_test_jthread([this](std::stop_token st) {
 116           while (!st.stop_requested()) {
 117             std::unique_lock lock{m_};
 118             cv_.wait(lock, st, [] { return false; });
 119           }
 120         });
 121       }
 122
 123     private:
 124       std::mutex m_;
 125       std::condition_variable_any cv_;
 126       std::jthread thread_;
 127     };
 128
 129     [[maybe_unused]] MyThread my_thread;
 130   }
 131
 132   // request_stop potentially in-between check and wait
 133   {
 134     std::stop_source ss;
 135     std::condition_variable_any cv;
 136     Mutex mutex;
 137     Lock lock{mutex};
 138
 139     std::atomic_bool pred_started        = false;
 140     std::atomic_bool request_stop_called = false;
 141     auto thread                          = support::make_test_thread([&]() {
 142       pred_started.wait(false);
 143       ss.request_stop();
 144       request_stop_called.store(true);
 145       request_stop_called.notify_all();
 146     });
 147
 148     std::same_as<bool> auto r = cv.wait(lock, ss.get_token(), [&]() {
 149       pred_started.store(true);
 150       pred_started.notify_all();
 151       request_stop_called.wait(false);
 152       return false;
 153     });
 154     assert(!r);
 155     thread.join();
 156
 157     assert(lock.owns_lock());
 158   }
 159
 160 #if !defined(TEST_HAS_NO_EXCEPTIONS)
 161   // Throws: Any exception thrown by pred.
 162   {
 163     std::stop_source ss;
 164     std::condition_variable_any cv;
 165     Mutex mutex;
 166     Lock lock{mutex};
 167
 168     try {
 169       cv.wait(lock, ss.get_token(), []() -> bool { throw 5; });
 170       assert(false);
 171     } catch (int i) {
 172       assert(i == 5);
 173     }
 174   }
 175 #endif //!defined(TEST_HAS_NO_EXCEPTIONS)
 176 }
 177
 178 int main(int, char**) {
 179   test<std::mutex, std::unique_lock<std::mutex>>();
 180   test<std::shared_mutex, std::shared_lock<std::shared_mutex>>();
 181
 182   return 0;
 183 }