Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 1 | //===----------------------------------------------------------------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is dual licensed under the MIT and the University of Illinois Open |
| 6 | // Source Licenses. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // UNSUPPORTED: libcpp-has-no-threads |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 11 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 12 | // <future> |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 13 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 14 | // class shared_future<R> |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 15 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 16 | // template <class Clock, class Duration> |
| 17 | // future_status |
| 18 | // wait_until(const chrono::time_point<Clock, Duration>& abs_time) const; |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 19 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 20 | #include <future> |
| 21 | #include <atomic> |
| 22 | #include <cassert> |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 23 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 24 | enum class WorkerThreadState { Uninitialized, AllowedToRun, Exiting }; |
| 25 | typedef std::chrono::milliseconds ms; |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 26 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 27 | std::atomic<WorkerThreadState> thread_state(WorkerThreadState::Uninitialized); |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 28 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 29 | void set_worker_thread_state(WorkerThreadState state) |
| 30 | { |
| 31 | thread_state.store(state, std::memory_order_relaxed); |
| 32 | } |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 33 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 34 | void wait_for_worker_thread_state(WorkerThreadState state) |
| 35 | { |
| 36 | while (thread_state.load(std::memory_order_relaxed) != state); |
| 37 | } |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 38 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 39 | void func1(std::promise<int> p) |
| 40 | { |
| 41 | wait_for_worker_thread_state(WorkerThreadState::AllowedToRun); |
| 42 | p.set_value(3); |
| 43 | set_worker_thread_state(WorkerThreadState::Exiting); |
| 44 | } |
Howard Hinnant | 99be823 | 2010-09-03 18:39:25 +0000 | [diff] [blame] | 45 | |
Eric Fiselier | 578c9e8 | 2015-02-11 01:25:57 +0000 | [diff] [blame] | 46 | int j = 0; |
| 47 | |
| 48 | void func3(std::promise<int&> p) |
| 49 | { |
| 50 | wait_for_worker_thread_state(WorkerThreadState::AllowedToRun); |
| 51 | j = 5; |
| 52 | p.set_value(j); |
| 53 | set_worker_thread_state(WorkerThreadState::Exiting); |
| 54 | } |
| 55 | |
| 56 | void func5(std::promise<void> p) |
| 57 | { |
| 58 | wait_for_worker_thread_state(WorkerThreadState::AllowedToRun); |
| 59 | p.set_value(); |
| 60 | set_worker_thread_state(WorkerThreadState::Exiting); |
| 61 | } |
| 62 | |
| 63 | int main() |
| 64 | { |
| 65 | typedef std::chrono::high_resolution_clock Clock; |
| 66 | { |
| 67 | typedef int T; |
| 68 | std::promise<T> p; |
| 69 | std::shared_future<T> f = p.get_future(); |
| 70 | std::thread(func1, std::move(p)).detach(); |
| 71 | assert(f.valid()); |
| 72 | assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout); |
| 73 | assert(f.valid()); |
| 74 | |
| 75 | // allow the worker thread to produce the result and wait until the worker is done |
| 76 | set_worker_thread_state(WorkerThreadState::AllowedToRun); |
| 77 | wait_for_worker_thread_state(WorkerThreadState::Exiting); |
| 78 | |
| 79 | assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready); |
| 80 | assert(f.valid()); |
| 81 | Clock::time_point t0 = Clock::now(); |
| 82 | f.wait(); |
| 83 | Clock::time_point t1 = Clock::now(); |
| 84 | assert(f.valid()); |
| 85 | assert(t1-t0 < ms(5)); |
| 86 | } |
| 87 | { |
| 88 | typedef int& T; |
| 89 | std::promise<T> p; |
| 90 | std::shared_future<T> f = p.get_future(); |
| 91 | std::thread(func3, std::move(p)).detach(); |
| 92 | assert(f.valid()); |
| 93 | assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout); |
| 94 | assert(f.valid()); |
| 95 | |
| 96 | // allow the worker thread to produce the result and wait until the worker is done |
| 97 | set_worker_thread_state(WorkerThreadState::AllowedToRun); |
| 98 | wait_for_worker_thread_state(WorkerThreadState::Exiting); |
| 99 | |
| 100 | assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready); |
| 101 | assert(f.valid()); |
| 102 | Clock::time_point t0 = Clock::now(); |
| 103 | f.wait(); |
| 104 | Clock::time_point t1 = Clock::now(); |
| 105 | assert(f.valid()); |
| 106 | assert(t1-t0 < ms(5)); |
| 107 | } |
| 108 | { |
| 109 | typedef void T; |
| 110 | std::promise<T> p; |
| 111 | std::shared_future<T> f = p.get_future(); |
| 112 | std::thread(func5, std::move(p)).detach(); |
| 113 | assert(f.valid()); |
| 114 | assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout); |
| 115 | assert(f.valid()); |
| 116 | |
| 117 | // allow the worker thread to produce the result and wait until the worker is done |
| 118 | set_worker_thread_state(WorkerThreadState::AllowedToRun); |
| 119 | wait_for_worker_thread_state(WorkerThreadState::Exiting); |
| 120 | |
| 121 | assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready); |
| 122 | assert(f.valid()); |
| 123 | Clock::time_point t0 = Clock::now(); |
| 124 | f.wait(); |
| 125 | Clock::time_point t1 = Clock::now(); |
| 126 | assert(f.valid()); |
| 127 | assert(t1-t0 < ms(5)); |
| 128 | } |
| 129 | } |