Line data    Source code

       1             : // Copyright (c) 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_NODE_MINI_MINER_H
       6             : #define BITCOIN_NODE_MINI_MINER_H
       7             : 
       8             : #include <txmempool.h>
       9             : 
      10             : #include <memory>
      11             : #include <optional>
      12             : #include <stdint.h>
      13             : 
      14             : namespace node {
      15             : 
      16             : // Container for tracking updates to ancestor feerate as we include ancestors in the "block"
      17             : class MiniMinerMempoolEntry
      18             : {
      19             :     const CAmount fee_individual;
      20             :     const CTransactionRef tx;
      21             :     const int64_t vsize_individual;
      22             :     CAmount fee_with_ancestors;
      23             :     int64_t vsize_with_ancestors;
      24             : 
      25             : // This class must be constructed while holding mempool.cs. After construction, the object's
      26             : // methods can be called without holding that lock.
      27             : 
      28             : public:
      29           0 :     explicit MiniMinerMempoolEntry(CTxMemPool::txiter entry) :
      30           0 :         fee_individual{entry->GetModifiedFee()},
      31           0 :         tx{entry->GetSharedTx()},
      32           0 :         vsize_individual(entry->GetTxSize()),
      33           0 :         fee_with_ancestors{entry->GetModFeesWithAncestors()},
      34           0 :         vsize_with_ancestors(entry->GetSizeWithAncestors())
      35           0 :     { }
      36             : 
      37           0 :     CAmount GetModifiedFee() const { return fee_individual; }
      38           0 :     CAmount GetModFeesWithAncestors() const { return fee_with_ancestors; }
      39           0 :     int64_t GetTxSize() const { return vsize_individual; }
      40           0 :     int64_t GetSizeWithAncestors() const { return vsize_with_ancestors; }
      41           0 :     const CTransaction& GetTx() const LIFETIMEBOUND { return *tx; }
      42           0 :     void UpdateAncestorState(int64_t vsize_change, CAmount fee_change) {
      43           0 :         vsize_with_ancestors += vsize_change;
      44           0 :         fee_with_ancestors += fee_change;
      45           0 :     }
      46             : };
      47             : 
      48             : // Comparator needed for std::set<MockEntryMap::iterator>
      49             : struct IteratorComparator
      50             : {
      51             :     template<typename I>
      52           0 :     bool operator()(const I& a, const I& b) const
      53             :     {
      54           0 :         return &(*a) < &(*b);
      55             :     }
      56             : };
      57             : 
      58             : /** A minimal version of BlockAssembler. Allows us to run the mining algorithm on a subset of
      59             :  * mempool transactions, ignoring consensus rules, to calculate mining scores. */
      60             : class MiniMiner
      61             : {
      62             :     // When true, a caller may use CalculateBumpFees(). Becomes false if we failed to retrieve
      63             :     // mempool entries (i.e. cluster size too large) or bump fees have already been calculated.
      64             :     bool m_ready_to_calculate{true};
      65             : 
      66             :     // Set once per lifetime, fill in during initialization.
      67             :     // txids of to-be-replaced transactions
      68             :     std::set<uint256> m_to_be_replaced;
      69             : 
      70             :     // If multiple argument outpoints correspond to the same transaction, cache them together in
      71             :     // a single entry indexed by txid. Then we can just work with txids since all outpoints from
      72             :     // the same tx will have the same bumpfee. Excludes non-mempool transactions.
      73             :     std::map<uint256, std::vector<COutPoint>> m_requested_outpoints_by_txid;
      74             : 
      75             :     // What we're trying to calculate.
      76             :     std::map<COutPoint, CAmount> m_bump_fees;
      77             : 
      78             :     // The constructed block template
      79             :     std::set<uint256> m_in_block;
      80             : 
      81             :     // Information on the current status of the block
      82             :     CAmount m_total_fees{0};
      83             :     int32_t m_total_vsize{0};
      84             : 
      85             :     /** Main data structure holding the entries, can be indexed by txid */
      86             :     std::map<uint256, MiniMinerMempoolEntry> m_entries_by_txid;
      87             :     using MockEntryMap = decltype(m_entries_by_txid);
      88             : 
      89             :     /** Vector of entries, can be sorted by ancestor feerate. */
      90             :     std::vector<MockEntryMap::iterator> m_entries;
      91             : 
      92             :     /** Map of txid to its descendants. Should be inclusive. */
      93             :     std::map<uint256, std::vector<MockEntryMap::iterator>> m_descendant_set_by_txid;
      94             : 
      95             :     /** Consider this ancestor package "mined" so remove all these entries from our data structures. */
      96             :     void DeleteAncestorPackage(const std::set<MockEntryMap::iterator, IteratorComparator>& ancestors);
      97             : 
      98             :     /** Perform some checks. */
      99             :     void SanityCheck() const;
     100             : 
     101             : public:
     102             :     /** Returns true if CalculateBumpFees may be called, false if not. */
     103           0 :     bool IsReadyToCalculate() const { return m_ready_to_calculate; }
     104             : 
     105             :     /** Build a block template until the target feerate is hit. */
     106             :     void BuildMockTemplate(const CFeeRate& target_feerate);
     107             : 
     108             :     /** Returns set of txids in the block template if one has been constructed. */
     109           0 :     std::set<uint256> GetMockTemplateTxids() const { return m_in_block; }
     110             : 
     111             :     MiniMiner(const CTxMemPool& mempool, const std::vector<COutPoint>& outpoints);
     112             : 
     113             :     /** Construct a new block template and, for each outpoint corresponding to a transaction that
     114             :      * did not make it into the block, calculate the cost of bumping those transactions (and their
     115             :      * ancestors) to the minimum feerate. Returns a map from outpoint to bump fee, or an empty map
     116             :      * if they cannot be calculated. */
     117             :     std::map<COutPoint, CAmount> CalculateBumpFees(const CFeeRate& target_feerate);
     118             : 
     119             :     /** Construct a new block template and, calculate the cost of bumping all transactions that did
     120             :      * not make it into the block to the target feerate. Returns the total bump fee, or std::nullopt
     121             :      * if it cannot be calculated. */
     122             :     std::optional<CAmount> CalculateTotalBumpFees(const CFeeRate& target_feerate);
     123             : };
     124             : } // namespace node
     125             : 
     126             : #endif // BITCOIN_NODE_MINI_MINER_H