output_queue.hpp

Go to the documentation of this file.

 
#ifndef OUTPUT_QUEUE_HPP_INCLUDED
#define OUTPUT_QUEUE_HPP_INCLUDED
 
#include <queue>
#include <cstddef> // std::size_t
#include <optional>
 
#include "net_ip/queue_stats.hpp"
 
namespace chops {
namespace net {
namespace detail {
 
// template parameter E is instantiated as either a shared_buffer or a shared_buffer and 
// endpoint, depending on IO handler; a size() method is expected for E
template <typename E>
class output_queue {
private:
 
  std::queue<E>       m_output_queue;
  std::size_t         m_current_num_bytes;
 
  // std::size_t         m_queue_size;
  // std::size_t         m_total_bufs_sent;
  // std::size_t         m_total_bytes_sent;
 
public:
 
  output_queue() noexcept : m_output_queue(), m_current_num_bytes(0u) { }
 
  // io handlers call this method to get next buffer of data, can be empty
  std::optional<E> get_next_element() {
    if (m_output_queue.empty()) {
      return std::optional<E> { };
    }
    E elem = m_output_queue.front();
    m_output_queue.pop();
    m_current_num_bytes -= elem.size();
    return std::optional<E> {elem};
  }
 
  void add_element(const E& element) {
    m_output_queue.push(element);
    m_current_num_bytes += element.size(); // note - possible integer overflow
  }
 
  chops::net::output_queue_stats get_queue_stats() const noexcept {
    return chops::net::output_queue_stats { m_output_queue.size(), m_current_num_bytes };
  }
 
  void clear() noexcept {
    std::queue<E>().swap(m_output_queue);
    m_current_num_bytes = 0u;
  }
 
};
 
} // end detail namespace
} // end net namespace
} // end chops namespace
 
#endif