libcxx/test/std/thread/futures/futures.unique_future/wait_until.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
  11
  12 // <future>
  13
  14 // class future<R>
  15
  16 // template <class Clock, class Duration>
  17 //   future_status
  18 //   wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
  19
  20 #include <atomic>
  21 #include <cassert>
  22 #include <chrono>
  23 #include <future>
  24
  25 #include "make_test_thread.h"
  26 #include "test_macros.h"
  27
  28 enum class WorkerThreadState { Uninitialized, AllowedToRun, Exiting };
  29 typedef std::chrono::milliseconds ms;
  30
  31 std::atomic<WorkerThreadState> thread_state(WorkerThreadState::Uninitialized);
  32
  33 void set_worker_thread_state(WorkerThreadState state)
  34 {
  35   thread_state.store(state, std::memory_order_relaxed);
  36 }
  37
  38 void wait_for_worker_thread_state(WorkerThreadState state)
  39 {
  40   while (thread_state.load(std::memory_order_relaxed) != state)
  41     std::this_thread::yield();
  42 }
  43
  44 void func1(std::promise<int> p)
  45 {
  46   wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
  47   p.set_value(3);
  48   set_worker_thread_state(WorkerThreadState::Exiting);
  49 }
  50
  51 int j = 0;
  52
  53 void func3(std::promise<int&> p)
  54 {
  55   wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
  56   j = 5;
  57   p.set_value(j);
  58   set_worker_thread_state(WorkerThreadState::Exiting);
  59 }
  60
  61 void func5(std::promise<void> p)
  62 {
  63   wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
  64   p.set_value();
  65   set_worker_thread_state(WorkerThreadState::Exiting);
  66 }
  67
  68 int main(int, char**)
  69 {
  70   typedef std::chrono::high_resolution_clock Clock;
  71   {
  72     typedef int T;
  73     std::promise<T> p;
  74     std::future<T> f = p.get_future();
  75     support::make_test_thread(func1, std::move(p)).detach();
  76     assert(f.valid());
  77     assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
  78     assert(f.valid());
  79
  80     // allow the worker thread to produce the result and wait until the worker is done
  81     set_worker_thread_state(WorkerThreadState::AllowedToRun);
  82     wait_for_worker_thread_state(WorkerThreadState::Exiting);
  83
  84     assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
  85     assert(f.valid());
  86     f.wait();
  87     assert(f.valid());
  88   }
  89   {
  90     typedef int& T;
  91     std::promise<T> p;
  92     std::future<T> f = p.get_future();
  93     support::make_test_thread(func3, std::move(p)).detach();
  94     assert(f.valid());
  95     assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
  96     assert(f.valid());
  97
  98     // allow the worker thread to produce the result and wait until the worker is done
  99     set_worker_thread_state(WorkerThreadState::AllowedToRun);
 100     wait_for_worker_thread_state(WorkerThreadState::Exiting);
 101
 102     assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
 103     assert(f.valid());
 104     f.wait();
 105     assert(f.valid());
 106   }
 107   {
 108     typedef void T;
 109     std::promise<T> p;
 110     std::future<T> f = p.get_future();
 111     support::make_test_thread(func5, std::move(p)).detach();
 112     assert(f.valid());
 113     assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
 114     assert(f.valid());
 115
 116     // allow the worker thread to produce the result and wait until the worker is done
 117     set_worker_thread_state(WorkerThreadState::AllowedToRun);
 118     wait_for_worker_thread_state(WorkerThreadState::Exiting);
 119
 120     assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
 121     assert(f.valid());
 122     f.wait();
 123     assert(f.valid());
 124   }
 125
 126   return 0;
 127 }