onion-wownero-explorer/ext/vpetrigocaches/fifo_cache_policy.hpp

#ifndef FIFO_CACHE_POLICY_HPP
#define FIFO_CACHE_POLICY_HPP

#include <list>
#include "cache_policy.hpp"

namespace caches
{

template <typename Key>
class FIFOCachePolicy : public ICachePolicy<Key>
{
 public:

  FIFOCachePolicy() = default;
  ~FIFOCachePolicy() = default;

  void Insert(const Key& key) override
  {
    fifo_queue.emplace_front(key);
  }

  // handle request to the key-element in a cache
  void Touch(const Key& key) override
  {
    // nothing to do here in the FIFO strategy
  }

  // handle element deletion from a cache
  void Erase(const Key& key) override
  {
    fifo_queue.pop_back();
  }

  // return a key of a replacement candidate
  const Key& ReplCandidate() const override
  {
    return fifo_queue.back();
  }

  // return a key of a displacement candidate
  void Clear() override
  {
    fifo_queue.clear();
  }

private:

  std::list<Key> fifo_queue;
};
} // namespace caches

#endif // FIFO_CACHE_POLICY_HPP