cs-policy.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2022,  Regents of the University of California,
 *                           Arizona Board of Regents,
 *                           Colorado State University,
 *                           University Pierre & Marie Curie, Sorbonne University,
 *                           Washington University in St. Louis,
 *                           Beijing Institute of Technology,
 *                           The University of Memphis.
 *
 * This file is part of NFD (Named Data Networking Forwarding Daemon).
 * See AUTHORS.md for complete list of NFD authors and contributors.
 *
 * NFD is free software: you can redistribute it and/or modify it under the terms
 * of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef NFD_DAEMON_TABLE_CS_POLICY_HPP
#define NFD_DAEMON_TABLE_CS_POLICY_HPP
 
#include "cs-entry.hpp"
 
namespace nfd::cs {
 
class Cs;
 
class Policy : noncopyable
{
public: // registry
  template<typename P>
  static void
  registerPolicy(const std::string& policyName = P::POLICY_NAME)
  {
    BOOST_ASSERT(!policyName.empty());
    auto r = getRegistry().insert_or_assign(policyName, [] { return make_unique<P>(); });
    BOOST_VERIFY(r.second);
  }
 
  static unique_ptr<Policy>
  create(const std::string& policyName);
 
  static std::set<std::string>
  getPolicyNames();
 
public:
  virtual
  ~Policy() = default;
 
  const std::string&
  getName() const noexcept
  {
    return m_policyName;
  }
 
  Cs*
  getCs() const noexcept
  {
    return m_cs;
  }
 
  void
  setCs(Cs* cs) noexcept
  {
    m_cs = cs;
  }
 
  size_t
  getLimit() const noexcept
  {
    return m_limit;
  }
 
  void
  setLimit(size_t nMaxEntries);
 
public:
  using EntryRef = Table::const_iterator;
 
  signal::Signal<Policy, EntryRef> beforeEvict;
 
  void
  afterInsert(EntryRef i);
 
  void
  afterRefresh(EntryRef i);
 
  void
  beforeErase(EntryRef i);
 
  void
  beforeUse(EntryRef i);
 
protected:
  virtual void
  doAfterInsert(EntryRef i) = 0;
 
  virtual void
  doAfterRefresh(EntryRef i) = 0;
 
  virtual void
  doBeforeErase(EntryRef i) = 0;
 
  virtual void
  doBeforeUse(EntryRef i) = 0;
 
  virtual void
  evictEntries() = 0;
 
protected:
  explicit
  Policy(std::string_view policyName);
 
  DECLARE_SIGNAL_EMIT(beforeEvict)
 
private: // registry
  using CreateFunc = std::function<unique_ptr<Policy>()>;
  using Registry = std::map<std::string, CreateFunc>; // indexed by policy name
 
  static Registry&
  getRegistry();
 
private:
  const std::string m_policyName;
  size_t m_limit;
  Cs* m_cs;
};
 
} // namespace nfd::cs
 
#define NFD_REGISTER_CS_POLICY(P)                      \
static class NfdAuto ## P ## CsPolicyRegistrationClass \
{                                                      \
public:                                                \
  NfdAuto ## P ## CsPolicyRegistrationClass()          \
  {                                                    \
    ::nfd::cs::Policy::registerPolicy<P>();            \
  }                                                    \
} g_nfdAuto ## P ## CsPolicyRegistrationVariable
 
#endif // NFD_DAEMON_TABLE_CS_POLICY_HPP