libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_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 // ALLOW_RETRIES: 2
  11
  12 // <condition_variable>
  13
  14 // class condition_variable;
  15
  16 // template <class Clock, class Duration, class Predicate>
  17 //     bool
  18 //     wait_until(unique_lock<mutex>& lock,
  19 //                const chrono::time_point<Clock, Duration>& abs_time,
  20 //                Predicate pred);
  21
  22 #include <condition_variable>
  23 #include <mutex>
  24 #include <thread>
  25 #include <chrono>
  26 #include <cassert>
  27
  28 #include "make_test_thread.h"
  29 #include "test_macros.h"
  30
  31 struct Clock
  32 {
  33     typedef std::chrono::milliseconds duration;
  34     typedef duration::rep             rep;
  35     typedef duration::period          period;
  36     typedef std::chrono::time_point<Clock> time_point;
  37     static const bool is_steady =  true;
  38
  39     static time_point now()
  40     {
  41         using namespace std::chrono;
  42         return time_point(duration_cast<duration>(
  43                 steady_clock::now().time_since_epoch()
  44                                                  ));
  45     }
  46 };
  47
  48 class Pred
  49 {
  50     int& i_;
  51 public:
  52     explicit Pred(int& i) : i_(i) {}
  53
  54     bool operator()() {return i_ != 0;}
  55 };
  56
  57 std::condition_variable cv;
  58 std::mutex mut;
  59
  60 int test1 = 0;
  61 int test2 = 0;
  62
  63 int runs = 0;
  64
  65 void f()
  66 {
  67     std::unique_lock<std::mutex> lk(mut);
  68     assert(test2 == 0);
  69     test1 = 1;
  70     cv.notify_one();
  71     Clock::time_point t0 = Clock::now();
  72     Clock::time_point t = t0 + Clock::duration(250);
  73     bool r = cv.wait_until(lk, t, Pred(test2));
  74     Clock::time_point t1 = Clock::now();
  75     if (runs == 0)
  76     {
  77         assert(t1 - t0 < Clock::duration(250));
  78         assert(test2 != 0);
  79         assert(r);
  80     }
  81     else
  82     {
  83         assert(t1 - t0 - Clock::duration(250) < Clock::duration(50));
  84         assert(test2 == 0);
  85         assert(!r);
  86     }
  87     ++runs;
  88 }
  89
  90 int main(int, char**)
  91 {
  92     {
  93         std::unique_lock<std::mutex> lk(mut);
  94         std::thread t = support::make_test_thread(f);
  95         assert(test1 == 0);
  96         while (test1 == 0)
  97             cv.wait(lk);
  98         assert(test1 != 0);
  99         test2 = 1;
 100         lk.unlock();
 101         cv.notify_one();
 102         t.join();
 103     }
 104     test1 = 0;
 105     test2 = 0;
 106     {
 107         std::unique_lock<std::mutex> lk(mut);
 108         std::thread t = support::make_test_thread(f);
 109         assert(test1 == 0);
 110         while (test1 == 0)
 111             cv.wait(lk);
 112         assert(test1 != 0);
 113         lk.unlock();
 114         t.join();
 115     }
 116
 117   return 0;
 118 }