cs-policy-priority-fifo.cpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
#include "cs-policy-priority-fifo.hpp"
#include "cs.hpp"
#include <ndn-cxx/util/signal.hpp>

namespace nfd {
namespace cs {
namespace priority_fifo {

const std::string PriorityFifoPolicy::POLICY_NAME = "fifo";

PriorityFifoPolicy::PriorityFifoPolicy()
  : Policy(POLICY_NAME)
{
}

PriorityFifoPolicy::~PriorityFifoPolicy()
{
  for (auto entryInfoMapPair : m_entryInfoMap) {
    delete entryInfoMapPair.second;
  }
}

void
PriorityFifoPolicy::doAfterInsert(iterator i)
{
  this->attachQueue(i);
  this->evictEntries();
}

void
PriorityFifoPolicy::doAfterRefresh(iterator i)
{
  this->detachQueue(i);
  this->attachQueue(i);
}

void
PriorityFifoPolicy::doBeforeErase(iterator i)
{
  this->detachQueue(i);
}

void
PriorityFifoPolicy::doBeforeUse(iterator i)
{
  BOOST_ASSERT(m_entryInfoMap.find(i) != m_entryInfoMap.end());
}

void
PriorityFifoPolicy::evictEntries()
{
  BOOST_ASSERT(this->getCs() != nullptr);

  while (this->getCs()->size() > this->getLimit()) {
    this->evictOne();
  }
}

void
PriorityFifoPolicy::evictOne()
{
  BOOST_ASSERT(!m_queues[QUEUE_UNSOLICITED].empty() ||
               !m_queues[QUEUE_STALE].empty() ||
               !m_queues[QUEUE_FIFO].empty());

  iterator i;
  if (!m_queues[QUEUE_UNSOLICITED].empty()) {
    i = m_queues[QUEUE_UNSOLICITED].front();
  }
  else if (!m_queues[QUEUE_STALE].empty()) {
    i = m_queues[QUEUE_STALE].front();
  }
  else if (!m_queues[QUEUE_FIFO].empty()) {
    i = m_queues[QUEUE_FIFO].front();
  }

  this->detachQueue(i);
  this->emitSignal(beforeEvict, i);
}

void
PriorityFifoPolicy::attachQueue(iterator i)
{
  BOOST_ASSERT(m_entryInfoMap.find(i) == m_entryInfoMap.end());

  EntryInfo* entryInfo = new EntryInfo();
  if (i->isUnsolicited()) {
    entryInfo->queueType = QUEUE_UNSOLICITED;
  }
  else if (i->isStale()) {
    entryInfo->queueType = QUEUE_STALE;
  }
  else {
    entryInfo->queueType = QUEUE_FIFO;

    if (i->canStale()) {
      entryInfo->moveStaleEventId = scheduler::schedule(i->getData().getFreshnessPeriod(),
                                              bind(&PriorityFifoPolicy::moveToStaleQueue, this, i));
    }
  }

  Queue& queue = m_queues[entryInfo->queueType];
  entryInfo->queueIt = queue.insert(queue.end(), i);
  m_entryInfoMap[i] = entryInfo;
}

void
PriorityFifoPolicy::detachQueue(iterator i)
{
  BOOST_ASSERT(m_entryInfoMap.find(i) != m_entryInfoMap.end());

  EntryInfo* entryInfo = m_entryInfoMap[i];
  if (entryInfo->queueType == QUEUE_FIFO) {
    scheduler::cancel(entryInfo->moveStaleEventId);
  }

  m_queues[entryInfo->queueType].erase(entryInfo->queueIt);
  m_entryInfoMap.erase(i);
  delete entryInfo;
}

void
PriorityFifoPolicy::moveToStaleQueue(iterator i)
{
  BOOST_ASSERT(m_entryInfoMap.find(i) != m_entryInfoMap.end());

  EntryInfo* entryInfo = m_entryInfoMap[i];
  BOOST_ASSERT(entryInfo->queueType == QUEUE_FIFO);

  m_queues[QUEUE_FIFO].erase(entryInfo->queueIt);

  entryInfo->queueType = QUEUE_STALE;
  Queue& queue = m_queues[QUEUE_STALE];
  entryInfo->queueIt = queue.insert(queue.end(), i);
  m_entryInfoMap[i] = entryInfo;
}

} // namespace priorityfifo
} // namespace cs
} // namespace nfd