031a3d203a
Summary: This patch marks *most* tests for `std::promise`, `std::future` and `std::shared_future` as unsupported in C++03. These tests fail in C++03 mode because they attempt to copy a `std::future` even though it is a `MoveOnly` type. AFAIK the missing move-semantics in `std::future` is the only reason these tests fail but without move semantics these classes are useless. For example even though `std::promise::set_value` and `std::promise::set_exception(...)` work in C++03 `std::promise` is still useless because we cannot call `std::promise::get_future(...)`. It might be possible to hack `std::move(...)` like we do for `std::unique_ptr` to make the move semantics work but I don't think it is worth the effort. Instead I think we should leave the `<future>` header as-is and mark the failing tests as `UNSUPPORTED`. I don't believe there are any users of `std::future` or `std::promise` in C++03 because they are so unusable. Therefore I am not concerned about losing test coverage and possibly breaking users. However because there are still parts of `<future>` that work in C++03 it would be wrong to `#ifdef` out the entire header. @mclow.lists Should we take further steps to prevent the use of `std::promise`, `std::future` and `std::shared_future` in C++03? Note: This patch also cleans up the tests and converts them to use `support/test_allocator.h` instead of a duplicate class in `test/std/futures/test_allocator.h`. Reviewers: mclow.lists Subscribers: vsk, mclow.lists, cfe-commits Differential Revision: http://reviews.llvm.org/D12135 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@246271 91177308-0d34-0410-b5e6-96231b3b80d8
131 lines
4.2 KiB
C++
131 lines
4.2 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// UNSUPPORTED: libcpp-has-no-threads
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// UNSUPPORTED: c++98, c++03
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// <future>
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// class shared_future<R>
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// template <class Clock, class Duration>
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// future_status
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// wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
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#include <future>
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#include <atomic>
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#include <cassert>
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enum class WorkerThreadState { Uninitialized, AllowedToRun, Exiting };
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typedef std::chrono::milliseconds ms;
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std::atomic<WorkerThreadState> thread_state(WorkerThreadState::Uninitialized);
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void set_worker_thread_state(WorkerThreadState state)
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{
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thread_state.store(state, std::memory_order_relaxed);
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}
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void wait_for_worker_thread_state(WorkerThreadState state)
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{
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while (thread_state.load(std::memory_order_relaxed) != state);
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}
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void func1(std::promise<int> p)
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{
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wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
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p.set_value(3);
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set_worker_thread_state(WorkerThreadState::Exiting);
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}
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int j = 0;
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void func3(std::promise<int&> p)
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{
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wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
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j = 5;
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p.set_value(j);
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set_worker_thread_state(WorkerThreadState::Exiting);
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}
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void func5(std::promise<void> p)
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{
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wait_for_worker_thread_state(WorkerThreadState::AllowedToRun);
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p.set_value();
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set_worker_thread_state(WorkerThreadState::Exiting);
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}
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int main()
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{
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typedef std::chrono::high_resolution_clock Clock;
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{
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typedef int T;
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std::promise<T> p;
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std::shared_future<T> f = p.get_future();
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std::thread(func1, std::move(p)).detach();
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assert(f.valid());
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
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assert(f.valid());
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// allow the worker thread to produce the result and wait until the worker is done
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set_worker_thread_state(WorkerThreadState::AllowedToRun);
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wait_for_worker_thread_state(WorkerThreadState::Exiting);
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
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assert(f.valid());
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Clock::time_point t0 = Clock::now();
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f.wait();
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Clock::time_point t1 = Clock::now();
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assert(f.valid());
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assert(t1-t0 < ms(5));
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}
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{
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typedef int& T;
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std::promise<T> p;
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std::shared_future<T> f = p.get_future();
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std::thread(func3, std::move(p)).detach();
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assert(f.valid());
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
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assert(f.valid());
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// allow the worker thread to produce the result and wait until the worker is done
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set_worker_thread_state(WorkerThreadState::AllowedToRun);
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wait_for_worker_thread_state(WorkerThreadState::Exiting);
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
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assert(f.valid());
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Clock::time_point t0 = Clock::now();
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f.wait();
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Clock::time_point t1 = Clock::now();
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assert(f.valid());
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assert(t1-t0 < ms(5));
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}
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{
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typedef void T;
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std::promise<T> p;
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std::shared_future<T> f = p.get_future();
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std::thread(func5, std::move(p)).detach();
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assert(f.valid());
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::timeout);
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assert(f.valid());
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// allow the worker thread to produce the result and wait until the worker is done
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set_worker_thread_state(WorkerThreadState::AllowedToRun);
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wait_for_worker_thread_state(WorkerThreadState::Exiting);
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assert(f.wait_until(Clock::now() + ms(10)) == std::future_status::ready);
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assert(f.valid());
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Clock::time_point t0 = Clock::now();
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f.wait();
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Clock::time_point t1 = Clock::now();
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assert(f.valid());
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assert(t1-t0 < ms(5));
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}
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}
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