Method dequeue

src/ugrep.cpp:2130–2148

pop a job

    // pop a job
    void dequeue(Job& job)
    {
      while (empty())
      {
        // we must lock and wait until the buffer is not empty
        std::unique_lock<std::mutex> lock(queue_mutex);
        queue_data.wait(lock);
        lock.unlock();
      }

      Job *next = head.load() + 1;
      if (next == &ring[DEFAULT_MAX_JOB_QUEUE_SIZE])
        next = ring;

      job = *head.load();
      head.store(next);
      --todo;
      queue_full.notify_one();
    }

    Job                     ring[DEFAULT_MAX_JOB_QUEUE_SIZE];
    std::atomic<Job*>       head;