text: // Copyright (c) 2021 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef BGL_TXORPHANAGE_H
  #define BGL_TXORPHANAGE_H
  
  #include <net.h>
  #include <primitives/block.h>
  #include <primitives/transaction.h>
  #include <sync.h>
  
  /** Guards orphan transactions and extra txs for compact blocks */
  extern RecursiveMutex g_cs_orphans;
  
  /** A class to track orphan transactions (failed on TX_MISSING_INPUTS)
   * Since we cannot distinguish orphans from bad transactions with
   * non-existent inputs, we heavily limit the number of orphans
   * we keep and the duration we keep them for.
   */
  class TxOrphanage {
  public:
      /** Add a new orphan transaction */
      bool AddTx(const CTransactionRef& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
  
      /** Check if we already have an orphan transaction (by txid or wtxid) */
      bool HaveTx(const GenTxid& gtxid) const LOCKS_EXCLUDED(::g_cs_orphans);
  
      /** Get an orphan transaction and its originating peer
       * (Transaction ref will be nullptr if not found)
       */
      std::pair<CTransactionRef, NodeId> GetTx(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
  
      /** Erase an orphan by txid */
      int EraseTx(const uint256& txid) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
  
      /** Erase all orphans announced by a peer (eg, after that peer disconnects) */
      void EraseForPeer(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
  
      /** Erase all orphans included in or invalidated by a new block */
      void EraseForBlock(const CBlock& block) LOCKS_EXCLUDED(::g_cs_orphans);
  
      /** Limit the orphanage to the given maximum */
      unsigned int LimitOrphans(unsigned int max_orphans) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
  
      /** Add any orphans that list a particular tx as a parent into a peer's work set
       * (ie orphans that may have found their final missing parent, and so should be reconsidered for the mempool) */
      void AddChildrenToWorkSet(const CTransaction& tx, std::set<uint256>& orphan_work_set) const EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
  
  protected:
      struct OrphanTx {
          CTransactionRef tx;
          NodeId fromPeer;
          int64_t nTimeExpire;
          size_t list_pos;
      };
  
      /** Map from txid to orphan transaction record. Limited by
       *  -maxorphantx/DEFAULT_MAX_ORPHAN_TRANSACTIONS */
      std::map<uint256, OrphanTx> m_orphans GUARDED_BY(g_cs_orphans);
  
      using OrphanMap = decltype(m_orphans);
  
      struct IteratorComparator
      {
          template<typename I>
          bool operator()(const I& a, const I& b) const
          {
              return &(*a) < &(*b);
          }
      };
  
      /** Index from the parents' COutPoint into the m_orphans. Used
       *  to remove orphan transactions from the m_orphans */
      std::map<COutPoint, std::set<OrphanMap::iterator, IteratorComparator>> m_outpoint_to_orphan_it GUARDED_BY(g_cs_orphans);
  
      /** Orphan transactions in vector for quick random eviction */
      std::vector<OrphanMap::iterator> m_orphan_list GUARDED_BY(g_cs_orphans);
  
      /** Index from wtxid into the m_orphans to lookup orphan
       *  transactions using their witness ids. */
      std::map<uint256, OrphanMap::iterator> m_wtxid_to_orphan_it GUARDED_BY(g_cs_orphans);
  };
  
  #endif // BGL_TXORPHANAGE_H
  