strategy.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_FW_STRATEGY_HPP
#define NFD_DAEMON_FW_STRATEGY_HPP
 
#include "forwarder.hpp"
#include "table/measurements-accessor.hpp"
 
#include <boost/lexical_cast/try_lexical_convert.hpp>
 
namespace nfd::fw {
 
class StrategyParameters;
 
class Strategy : noncopyable
{
public: // registry
  template<typename S>
  static void
  registerType(const Name& strategyName = S::getStrategyName())
  {
    BOOST_ASSERT(strategyName.size() > 1);
    BOOST_ASSERT(strategyName.at(-1).isVersion());
    auto r = getRegistry().insert_or_assign(strategyName, [] (auto&&... args) {
      return make_unique<S>(std::forward<decltype(args)>(args)...);
    });
    BOOST_VERIFY(r.second);
  }
 
  static bool
  canCreate(const Name& instanceName);
 
  static unique_ptr<Strategy>
  create(const Name& instanceName, Forwarder& forwarder);
 
  static bool
  areSameType(const Name& instanceNameA, const Name& instanceNameB);
 
  [[nodiscard]] static std::set<Name>
  listRegistered();
 
public: // constructor, destructor, strategy info
  explicit
  Strategy(Forwarder& forwarder);
 
  virtual
  ~Strategy();
 
#ifdef DOXYGEN
  static const Name&
  getStrategyName();
#endif
 
  const Name&
  getInstanceName() const noexcept
  {
    return m_name;
  }
 
public: // triggers
  virtual void
  afterReceiveInterest(const Interest& interest, const FaceEndpoint& ingress,
                       const shared_ptr<pit::Entry>& pitEntry) = 0;
 
  virtual void
  afterContentStoreHit(const Data& data, const FaceEndpoint& ingress,
                       const shared_ptr<pit::Entry>& pitEntry);
 
  virtual void
  beforeSatisfyInterest(const Data& data, const FaceEndpoint& ingress,
                        const shared_ptr<pit::Entry>& pitEntry);
 
  virtual void
  afterReceiveData(const Data& data, const FaceEndpoint& ingress,
                   const shared_ptr<pit::Entry>& pitEntry);
 
  virtual void
  afterReceiveNack(const lp::Nack& nack, const FaceEndpoint& ingress,
                   const shared_ptr<pit::Entry>& pitEntry);
 
  virtual void
  onDroppedInterest(const Interest& interest, Face& egress);
 
  virtual void
  afterNewNextHop(const fib::NextHop& nextHop, const shared_ptr<pit::Entry>& pitEntry);
 
protected: // actions
  NFD_VIRTUAL_WITH_TESTS pit::OutRecord*
  sendInterest(const Interest& interest, Face& egress, const shared_ptr<pit::Entry>& pitEntry);
 
  NFD_VIRTUAL_WITH_TESTS bool
  sendData(const Data& data, Face& egress, const shared_ptr<pit::Entry>& pitEntry);
 
  NFD_VIRTUAL_WITH_TESTS void
  sendDataToAll(const Data& data, const shared_ptr<pit::Entry>& pitEntry, const Face& inFace);
 
  NFD_VIRTUAL_WITH_TESTS void
  rejectPendingInterest(const shared_ptr<pit::Entry>& pitEntry)
  {
    this->setExpiryTimer(pitEntry, 0_ms);
  }
 
  NFD_VIRTUAL_WITH_TESTS bool
  sendNack(const lp::NackHeader& header, Face& egress, const shared_ptr<pit::Entry>& pitEntry)
  {
    return m_forwarder.onOutgoingNack(header, egress, pitEntry);
  }
 
  void
  sendNacks(const lp::NackHeader& header, const shared_ptr<pit::Entry>& pitEntry,
            std::initializer_list<const Face*> exceptFaces = {});
 
  void
  setExpiryTimer(const shared_ptr<pit::Entry>& pitEntry, time::milliseconds duration)
  {
    m_forwarder.setExpiryTimer(pitEntry, duration);
  }
 
protected: // accessors
  const fib::Entry&
  lookupFib(const pit::Entry& pitEntry) const;
 
  MeasurementsAccessor&
  getMeasurements() noexcept
  {
    return m_measurements;
  }
 
  Face*
  getFace(FaceId id) const noexcept
  {
    return getFaceTable().get(id);
  }
 
  const FaceTable&
  getFaceTable() const noexcept
  {
    return m_forwarder.m_faceTable;
  }
 
protected: // instance name
  struct ParsedInstanceName
  {
    Name strategyName; 
    std::optional<uint64_t> version; 
    PartialName parameters; 
  };
 
  static ParsedInstanceName
  parseInstanceName(const Name& input);
 
  static Name
  makeInstanceName(const Name& input, const Name& strategyName);
 
  void
  setInstanceName(const Name& name) noexcept
  {
    m_name = name;
  }
 
NFD_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
  static StrategyParameters
  parseParameters(const PartialName& params);
 
private: // registry
  using CreateFunc = std::function<unique_ptr<Strategy>(Forwarder&, const Name& /*strategyName*/)>;
  using Registry = std::map<Name, CreateFunc>; // indexed by strategy name
 
  static Registry&
  getRegistry();
 
  static Registry::const_iterator
  find(const Name& instanceName);
 
protected: // accessors
  signal::Signal<FaceTable, Face>& afterAddFace;
  signal::Signal<FaceTable, Face>& beforeRemoveFace;
 
private: // instance fields
  Name m_name;
  Forwarder& m_forwarder;
  MeasurementsAccessor m_measurements;
};
 
class StrategyParameters : public std::map<std::string, std::string>
{
public:
  // Note: only arithmetic types are supported by getOrDefault() for now
 
  template<typename T>
  std::enable_if_t<std::is_signed_v<T>, T>
  getOrDefault(const key_type& key, const T& defaultVal) const
  {
    auto it = find(key);
    if (it == end()) {
      return defaultVal;
    }
 
    T val{};
    if (!boost::conversion::try_lexical_convert(it->second, val)) {
      NDN_THROW(std::invalid_argument(key + " value is malformed"));
    }
    return val;
  }
 
  template<typename T>
  std::enable_if_t<std::is_unsigned_v<T>, T>
  getOrDefault(const key_type& key, const T& defaultVal) const
  {
    auto it = find(key);
    if (it == end()) {
      return defaultVal;
    }
 
    if (it->second.find('-') != std::string::npos) {
      NDN_THROW(std::invalid_argument(key + " cannot be negative"));
    }
 
    T val{};
    if (!boost::conversion::try_lexical_convert(it->second, val)) {
      NDN_THROW(std::invalid_argument(key + " value is malformed"));
    }
    return val;
  }
};
 
} // namespace nfd::fw
 
#define NFD_REGISTER_STRATEGY(S)                       \
static class NfdAuto ## S ## StrategyRegistrationClass \
{                                                      \
public:                                                \
  NfdAuto ## S ## StrategyRegistrationClass()          \
  {                                                    \
    ::nfd::fw::Strategy::registerType<S>();            \
  }                                                    \
} g_nfdAuto ## S ## StrategyRegistrationVariable
 
#endif // NFD_DAEMON_FW_STRATEGY_HPP