FollyQueue.hpp

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#ifndef IOMANAGER_INCLUDE_IOMANAGER_FOLLYQUEUE_HPP_
#define IOMANAGER_INCLUDE_IOMANAGER_FOLLYQUEUE_HPP_
 
#include "iomanager/queue/Queue.hpp"
 
#include "folly/concurrency/DynamicBoundedQueue.h"
#include "logging/Logging.hpp"
 
#include <string>
#include <utility> // For std::move
 
namespace dunedaq::iomanager {
 
template<class T, template<typename, bool> class FollyQueueType>
class FollyQueue : public Queue<T>
{
public:
  using value_t = T;
  using duration_t = typename Queue<T>::duration_t;
 
  explicit FollyQueue(const std::string& name, size_t capacity)
    : Queue<T>(name)
    , m_queue(capacity)
    , m_capacity(capacity)
  {}
 
  size_t get_capacity() const noexcept override { return m_capacity; }
 
  size_t get_num_elements() const noexcept override { return m_queue.size(); }
 
  bool can_pop() const noexcept override { return !m_queue.empty(); }
 
  void pop(value_t& val, const duration_t& dur) override
  {
    if (!m_queue.try_dequeue_for(val, dur)) {
      throw QueueTimeoutExpired(
        ERS_HERE, this->get_name(), "pop", std::chrono::duration_cast<std::chrono::milliseconds>(dur).count());
    }
  }
  bool try_pop(value_t& val, const duration_t& dur) override
  {
    if (!m_queue.try_dequeue_for(val, dur)) {
      return false;
    }
    return true;
  }
 
  bool can_push() const noexcept override { return m_queue.size() < this->get_capacity(); }
 
  void push(value_t&& t, const duration_t& dur) override
  {
    if (!m_queue.try_enqueue_for(std::move(t), dur)) {
      throw QueueTimeoutExpired(
        ERS_HERE, this->get_name(), "push", std::chrono::duration_cast<std::chrono::milliseconds>(dur).count());
    }
  }
  bool try_push(value_t&& t, const duration_t& dur) override
  {
    if (!m_queue.try_enqueue_for(std::move(t), dur)) {
      ers::error(QueueTimeoutExpired(
        ERS_HERE, this->get_name(), "push", std::chrono::duration_cast<std::chrono::milliseconds>(dur).count()));
      return false;
    }
    return true;
  }
 
  // Delete the copy and move operations
  FollyQueue(const FollyQueue&) = delete;
  FollyQueue& operator=(const FollyQueue&) = delete;
  FollyQueue(FollyQueue&&) = delete;
  FollyQueue& operator=(FollyQueue&&) = delete;
 
private:
  // The boolean argument is `MayBlock`, where "block" appears to mean
  // "make a system call". With `MayBlock` set to false, the queue
  // just spin-waits, so we want true
  FollyQueueType<T, true> m_queue;
  size_t m_capacity;
};
 
template<typename T>
using FollySPSCQueue = FollyQueue<T, folly::DSPSCQueue>;
 
template<typename T>
using FollyMPMCQueue = FollyQueue<T, folly::DMPMCQueue>;
 
} // namespace dunedaq::iomanager
 
#endif // IOMANAGER_INCLUDE_IOMANAGER_FOLLYQUEUE_HPP_
 
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