Method WaitOrRunTasks

dali/core/exec/thread_pool_base.cc:268–297

template <typename Condition>
bool ThreadPoolBase::WaitOrRunTasks(std::condition_variable &cv, Condition &&condition) {
  // This function waits cooperatively for a condition (e.g. job completion) to be met - while
  // it's not met, the calling thread participates in executing the tasks from this thread pool.

  // This function should be used only from within this thread pool's threads.
  assert(this_thread_pool() == this);

  while (!shutdown_pending_) {
    std::unique_lock lock(mtx_);
    bool ret;
    while (!(ret = condition()) && tasks_.empty())
      cv.wait_for(lock, std::chrono::microseconds(100));

    if (ret || condition())  // re-evaluate the condition after the timeout, just in case
      return true;

    if (shutdown_pending_)
      return condition();

    // The condition was not met in 100µs, let's try to pick up some tasks

    bool acquired = sem_.try_acquire();
    if (!acquired)
      continue;  // no tasks? spin

    assert(!tasks_.empty() && "Semaphore acquired but no tasks present.");
    PopUnlockAndRunTask(lock);
  }
  return condition();
}

}  // namespace dali