Class CountDownLatch

include/process/count_down_latch.hpp:24–50

An implementation of a count down latch that returns a Future to signify when it gets triggered.

// An implementation of a count down latch that returns a Future to
// signify when it gets triggered.
class CountDownLatch
{
public:
  CountDownLatch(size_t count = 1) : count(count) {}

  void decrement()
  {
    size_t expected = count.load();
    while (expected > 0) {
      if (count.compare_exchange_strong(expected, expected - 1)) {
        if (expected == 1) {
          promise.set(Nothing());
        }
        break;
      }
    }
  }

  Future<Nothing> triggered()
  {
    return promise.future();
  }

private:
  std::atomic<size_t> count;
  Promise<Nothing> promise;
};

} // namespace process {