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       1                 :            : // Copyright (c) 2021-2022 The Bitcoin Core developers
       2                 :            : // Distributed under the MIT software license, see the accompanying
       3                 :            : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4                 :            : 
       5                 :            : #ifndef BITCOIN_TXORPHANAGE_H
       6                 :            : #define BITCOIN_TXORPHANAGE_H
       7                 :            : 
       8                 :            : #include <net.h>
       9                 :            : #include <primitives/block.h>
      10                 :            : #include <primitives/transaction.h>
      11                 :            : #include <sync.h>
      12                 :            : 
      13                 :            : #include <map>
      14                 :            : #include <set>
      15                 :            : 
      16                 :            : /** A class to track orphan transactions (failed on TX_MISSING_INPUTS)
      17                 :            :  * Since we cannot distinguish orphans from bad transactions with
      18                 :            :  * non-existent inputs, we heavily limit the number of orphans
      19                 :            :  * we keep and the duration we keep them for.
      20                 :            :  */
      21                 :            : class TxOrphanage {
      22                 :            : public:
      23                 :            :     /** Add a new orphan transaction */
      24                 :            :     bool AddTx(const CTransactionRef& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      25                 :            : 
      26                 :            :     /** Check if we already have an orphan transaction (by txid or wtxid) */
      27                 :            :     bool HaveTx(const GenTxid& gtxid) const EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      28                 :            : 
      29                 :            :     /** Extract a transaction from a peer's work set
      30                 :            :      *  Returns nullptr if there are no transactions to work on.
      31                 :            :      *  Otherwise returns the transaction reference, and removes
      32                 :            :      *  it from the work set.
      33                 :            :      */
      34                 :            :     CTransactionRef GetTxToReconsider(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      35                 :            : 
      36                 :            :     /** Erase an orphan by txid */
      37                 :            :     int EraseTx(const uint256& txid) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      38                 :            : 
      39                 :            :     /** Erase all orphans announced by a peer (eg, after that peer disconnects) */
      40                 :            :     void EraseForPeer(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      41                 :            : 
      42                 :            :     /** Erase all orphans included in or invalidated by a new block */
      43                 :            :     void EraseForBlock(const CBlock& block) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      44                 :            : 
      45                 :            :     /** Limit the orphanage to the given maximum */
      46                 :            :     void LimitOrphans(unsigned int max_orphans) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
      47                 :            : 
      48                 :            :     /** Add any orphans that list a particular tx as a parent into the from peer's work set */
      49                 :            :     void AddChildrenToWorkSet(const CTransaction& tx) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);;
      50                 :            : 
      51                 :            :     /** Does this peer have any work to do? */
      52                 :            :     bool HaveTxToReconsider(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);;
      53                 :            : 
      54                 :            :     /** Return how many entries exist in the orphange */
      55                 :       5170 :     size_t Size() EXCLUSIVE_LOCKS_REQUIRED(!m_mutex)
      56                 :            :     {
      57                 :       5170 :         LOCK(m_mutex);
      58                 :       5170 :         return m_orphans.size();
      59                 :       5170 :     }
      60                 :            : 
      61                 :            : protected:
      62                 :            :     /** Guards orphan transactions */
      63                 :            :     mutable Mutex m_mutex;
      64                 :            : 
      65                 :            :     struct OrphanTx {
      66                 :            :         CTransactionRef tx;
      67                 :            :         NodeId fromPeer;
      68                 :            :         int64_t nTimeExpire;
      69                 :            :         size_t list_pos;
      70                 :            :     };
      71                 :            : 
      72                 :            :     /** Map from txid to orphan transaction record. Limited by
      73                 :            :      *  -maxorphantx/DEFAULT_MAX_ORPHAN_TRANSACTIONS */
      74                 :            :     std::map<uint256, OrphanTx> m_orphans GUARDED_BY(m_mutex);
      75                 :            : 
      76                 :            :     /** Which peer provided the orphans that need to be reconsidered */
      77                 :            :     std::map<NodeId, std::set<uint256>> m_peer_work_set GUARDED_BY(m_mutex);
      78                 :            : 
      79                 :            :     using OrphanMap = decltype(m_orphans);
      80                 :            : 
      81                 :            :     struct IteratorComparator
      82                 :            :     {
      83                 :            :         template<typename I>
      84                 :    2021453 :         bool operator()(const I& a, const I& b) const
      85                 :            :         {
      86                 :    2021453 :             return &(*a) < &(*b);
      87                 :            :         }
      88                 :            :     };
      89                 :            : 
      90                 :            :     /** Index from the parents' COutPoint into the m_orphans. Used
      91                 :            :      *  to remove orphan transactions from the m_orphans */
      92                 :            :     std::map<COutPoint, std::set<OrphanMap::iterator, IteratorComparator>> m_outpoint_to_orphan_it GUARDED_BY(m_mutex);
      93                 :            : 
      94                 :            :     /** Orphan transactions in vector for quick random eviction */
      95                 :            :     std::vector<OrphanMap::iterator> m_orphan_list GUARDED_BY(m_mutex);
      96                 :            : 
      97                 :            :     /** Index from wtxid into the m_orphans to lookup orphan
      98                 :            :      *  transactions using their witness ids. */
      99                 :            :     std::map<uint256, OrphanMap::iterator> m_wtxid_to_orphan_it GUARDED_BY(m_mutex);
     100                 :            : 
     101                 :            :     /** Erase an orphan by txid */
     102                 :            :     int EraseTxNoLock(const uint256& txid) EXCLUSIVE_LOCKS_REQUIRED(m_mutex);
     103                 :            : };
     104                 :            : 
     105                 :            : #endif // BITCOIN_TXORPHANAGE_H