signal_co_spawn.cc

#include <chrono>
#include <exception>
#include <latch>
#include <thread>
#include <boost/asio.hpp>
#include <gtest/gtest.h>

using namespace std::chrono_literals;
namespace asio = boost::asio;

void callback(std::exception_ptr eptr)
{
  ASSERT_TRUE(eptr);
  try {
    std::rethrow_exception(eptr);
  } catch (const boost::system::system_error& e) {
    EXPECT_EQ(e.code(), std::errc::operation_canceled);
  } catch (const std::exception&) {
    EXPECT_THROW(throw, boost::system::system_error);
  }
}

void thread_entry(asio::cancellation_signal& signal,
                  std::latch& spawned)
{
  asio::io_context ctx;
  asio::co_spawn(ctx,
      [&spawned] () -> asio::awaitable<void> {
        spawned.count_down();
        asio::steady_timer timer{co_await asio::this_coro::executor, 1h};
        co_await timer.async_wait(asio::use_awaitable);
      }, bind_cancellation_slot(signal.slot(), callback));
  ctx.run();
}

TEST(CoSpawn, Cancel)
{
  asio::cancellation_signal signal;
  std::latch spawned{1};

  auto thread = std::thread{thread_entry, std::ref(signal), std::ref(spawned)};
  spawned.wait();
  signal.emit(asio::cancellation_type::terminal);

  thread.join();
}