text: //------------------------------------------------------------------------------
  /*
      This file is part of rippled: https://github.com/ripple/rippled
      Copyright (c) 2012, 2013 Ripple Labs Inc.
  
      Permission to use, copy, modify, and/or distribute this software for any
      purpose  with  or without fee is hereby granted, provided that the above
      copyright notice and this permission notice appear in all copies.
  
      THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
      MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
      ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
      WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
      ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
      OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
  //==============================================================================
  
  #ifndef RIPPLE_APP_LEDGER_INBOUNDLEDGER_H_INCLUDED
  #define RIPPLE_APP_LEDGER_INBOUNDLEDGER_H_INCLUDED
  
  #include <ripple/app/ledger/Ledger.h>
  #include <ripple/app/main/Application.h>
  #include <ripple/basics/CountedObject.h>
  #include <ripple/overlay/PeerSet.h>
  #include <mutex>
  #include <set>
  #include <utility>
  
  namespace ripple {
  
  // A ledger we are trying to acquire
  class InboundLedger final : public PeerSet,
                              public std::enable_shared_from_this<InboundLedger>,
                              public CountedObject<InboundLedger>
  {
  public:
      using clock_type = beast::abstract_clock<std::chrono::steady_clock>;
  
      static char const*
      getCountedObjectName()
      {
          return "InboundLedger";
      }
  
      using PeerDataPairType =
          std::pair<std::weak_ptr<Peer>, std::shared_ptr<protocol::TMLedgerData>>;
  
      // These are the reasons we might acquire a ledger
      enum class Reason {
          HISTORY,   // Acquiring past ledger
          SHARD,     // Acquiring for shard
          GENERIC,   // Generic other reasons
          CONSENSUS  // We believe the consensus round requires this ledger
      };
  
      InboundLedger(
          Application& app,
          uint256 const& hash,
          std::uint32_t seq,
          Reason reason,
          clock_type&);
  
      ~InboundLedger();
  
      // Called when another attempt is made to fetch this same ledger
      void
      update(std::uint32_t seq);
  
      /** Returns true if we got all the data. */
      bool
      isComplete() const
      {
          return mComplete;
      }
  
      /** Returns false if we failed to get the data. */
      bool
      isFailed() const
      {
          return mFailed;
      }
  
      std::shared_ptr<Ledger const>
      getLedger() const
      {
          return mLedger;
      }
  
      std::uint32_t
      getSeq() const
      {
          return mSeq;
      }
  
      bool
      checkLocal();
      void
      init(ScopedLockType& collectionLock);
  
      bool
      gotData(
          std::weak_ptr<Peer>,
          std::shared_ptr<protocol::TMLedgerData> const&);
  
      using neededHash_t =
          std::pair<protocol::TMGetObjectByHash::ObjectType, uint256>;
  
      /** Return a Json::objectValue. */
      Json::Value
      getJson(int);
  
      void
      runData();
  
      void
      touch()
      {
          mLastAction = m_clock.now();
      }
  
      clock_type::time_point
      getLastAction() const
      {
          return mLastAction;
      }
  
  private:
      enum class TriggerReason { added, reply, timeout };
  
      void
      filterNodes(
          std::vector<std::pair<SHAMapNodeID, uint256>>& nodes,
          TriggerReason reason);
  
      void
      trigger(std::shared_ptr<Peer> const&, TriggerReason);
  
      std::vector<neededHash_t>
      getNeededHashes();
  
      void
      addPeers();
  
      void
      tryDB(NodeStore::Database& srcDB);
  
      void
      done();
  
      void
      onTimer(bool progress, ScopedLockType& peerSetLock) override;
  
      void
      queueJob() override;
  
      void
      onPeerAdded(std::shared_ptr<Peer> const& peer) override
      {
          // For historical nodes, do not trigger too soon
          // since a fetch pack is probably coming
          if (mReason != Reason::HISTORY)
              trigger(peer, TriggerReason::added);
      }
  
      std::size_t
      getPeerCount() const;
  
      std::weak_ptr<PeerSet>
      pmDowncast() override;
  
      int
      processData(std::shared_ptr<Peer> peer, protocol::TMLedgerData& data);
  
      bool
      takeHeader(std::string const& data);
  
      void
      receiveNode(protocol::TMLedgerData& packet, SHAMapAddNode&);
  
      bool
      takeTxRootNode(Slice const& data, SHAMapAddNode&);
  
      bool
      takeAsRootNode(Slice const& data, SHAMapAddNode&);
  
      std::vector<uint256>
      neededTxHashes(int max, SHAMapSyncFilter* filter) const;
  
      std::vector<uint256>
      neededStateHashes(int max, SHAMapSyncFilter* filter) const;
  
      clock_type& m_clock;
      clock_type::time_point mLastAction;
  
      std::shared_ptr<Ledger> mLedger;
      bool mHaveHeader;
      bool mHaveState;
      bool mHaveTransactions;
      bool mSignaled;
      bool mByHash;
      std::uint32_t mSeq;
      Reason const mReason;
  
      std::set<uint256> mRecentNodes;
  
      SHAMapAddNode mStats;
  
      // Data we have received from peers
      std::mutex mReceivedDataLock;
      std::vector<PeerDataPairType> mReceivedData;
      bool mReceiveDispatched;
  };
  
  /** Deserialize a ledger header from a byte array. */
  LedgerInfo
  deserializeHeader(Slice data);
  
  /** Deserialize a ledger header (prefixed with 4 bytes) from a byte array. */
  LedgerInfo
  deserializePrefixedHeader(Slice data);
  
  }  // namespace ripple
  
  #endif
  