text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2018 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 BITCOIN_MINER_H
  #define BITCOIN_MINER_H
  
  #include <primitives/block.h>
  #include <txmempool.h>
  #include <validate/validation.h>
  
  #include <stdint.h>
  #include <memory>
  #include <boost/multi_index_container.hpp>
  #include <boost/multi_index/ordered_index.hpp>
  
  class CBlockIndex;
  class CChainParams;
  class CScript;
  
  namespace Consensus { struct Params; };
  
  static const bool DEFAULT_PRINTPRIORITY = false;
  
  struct CBlockTemplate
  {
      CBlock block;
      std::vector<CAmount> vTxFees;
      std::vector<int64_t> vTxSigOpsCost;
      std::vector<unsigned char> vchCoinbaseCommitment;
  };
  
  // Container for tracking updates to ancestor feerate as we include (parent)
  // transactions in a block
  struct CTxMemPoolModifiedEntry {
      explicit CTxMemPoolModifiedEntry(CTxMemPool::txiter entry)
      {
          iter = entry;
          nSizeWithAncestors = entry->GetSizeWithAncestors();
          nModFeesWithAncestors = entry->GetModFeesWithAncestors();
          nSigOpCostWithAncestors = entry->GetSigOpCostWithAncestors();
      }
  
      int64_t GetModifiedFee() const { return iter->GetModifiedFee(); }
      uint64_t GetSizeWithAncestors() const { return nSizeWithAncestors; }
      CAmount GetModFeesWithAncestors() const { return nModFeesWithAncestors; }
      size_t GetTxSize() const { return iter->GetTxSize(); }
      const CTransaction& GetTx() const { return iter->GetTx(); }
  
      CTxMemPool::txiter iter;
      uint64_t nSizeWithAncestors;
      CAmount nModFeesWithAncestors;
      int64_t nSigOpCostWithAncestors;
  };
  
  /** Comparator for CTxMemPool::txiter objects.
   *  It simply compares the internal memory address of the CTxMemPoolEntry object
   *  pointed to. This means it has no meaning, and is only useful for using them
   *  as key in other indexes.
   */
  struct CompareCTxMemPoolIter {
      bool operator()(const CTxMemPool::txiter& a, const CTxMemPool::txiter& b) const
      {
          return &(*a) < &(*b);
      }
  };
  
  struct modifiedentry_iter {
      typedef CTxMemPool::txiter result_type;
      result_type operator() (const CTxMemPoolModifiedEntry &entry) const
      {
          return entry.iter;
      }
  };
  
  // A comparator that sorts transactions based on number of ancestors.
  // This is sufficient to sort an ancestor package in an order that is valid
  // to appear in a block.
  struct CompareTxIterByAncestorCount {
      bool operator()(const CTxMemPool::txiter &a, const CTxMemPool::txiter &b) const
      {
          if (a->GetCountWithAncestors() != b->GetCountWithAncestors())
              return a->GetCountWithAncestors() < b->GetCountWithAncestors();
          return CTxMemPool::CompareIteratorByHash()(a, b);
      }
  };
  
  typedef boost::multi_index_container<
      CTxMemPoolModifiedEntry,
      boost::multi_index::indexed_by<
          boost::multi_index::ordered_unique<
              modifiedentry_iter,
              CompareCTxMemPoolIter
          >,
          // sorted by modified ancestor fee rate
          boost::multi_index::ordered_non_unique<
              // Reuse same tag from CTxMemPool's similar index
              boost::multi_index::tag<ancestor_score>,
              boost::multi_index::identity<CTxMemPoolModifiedEntry>,
              CompareTxMemPoolEntryByAncestorFee
          >
      >
  > indexed_modified_transaction_set;
  
  typedef indexed_modified_transaction_set::nth_index<0>::type::iterator modtxiter;
  typedef indexed_modified_transaction_set::index<ancestor_score>::type::iterator modtxscoreiter;
  
  struct update_for_parent_inclusion
  {
      explicit update_for_parent_inclusion(CTxMemPool::txiter it) : iter(it) {}
  
      void operator() (CTxMemPoolModifiedEntry &e)
      {
          e.nModFeesWithAncestors -= iter->GetFee();
          e.nSizeWithAncestors -= iter->GetTxSize();
          e.nSigOpCostWithAncestors -= iter->GetSigOpCost();
      }
  
      CTxMemPool::txiter iter;
  };
  
  /** Generate a new block, without valid proof-of-work */
  class BlockAssembler
  {
  private:
      // The constructed block template
      std::unique_ptr<CBlockTemplate> pblocktemplate;
      // A convenience pointer that always refers to the CBlock in pblocktemplate
      CBlock* pblock;
  
      // Configuration parameters for the block size
      bool fIncludeWitness;
      unsigned int nBlockMaxWeight;
      CFeeRate blockMinFeeRate;
  
      // Information on the current status of the block
      uint64_t nBlockWeight;
      uint64_t nBlockTx;
      uint64_t nBlockSigOpsCost;
      CAmount nFees;
      CTxMemPool::setEntries inBlock;
  
      // Chain context for the block
      int nHeight;
      int64_t nLockTimeCutoff;
      const CChainParams& chainparams;
  
  public:
      struct Options {
          Options();
          size_t nBlockMaxWeight;
          CFeeRate blockMinFeeRate;
      };
  
      explicit BlockAssembler(const CChainParams& params);
      BlockAssembler(const CChainParams& params, const Options& options);
  
      /** Construct a new block template with coinbase to scriptPubKeyIn */
      std::unique_ptr<CBlockTemplate> CreateNewBlock(const CScript& scriptPubKeyIn, bool fMineWitnessTx=true);
  
  private:
      // utility functions
      /** Clear the block's state and prepare for assembling a new block */
      void resetBlock();
      /** Add a tx to the block */
      void AddToBlock(CTxMemPool::txiter iter);
  
      // Methods for how to add transactions to a block.
      /** Add transactions based on feerate including unconfirmed ancestors
        * Increments nPackagesSelected / nDescendantsUpdated with corresponding
        * statistics from the package selection (for logging statistics). */
      void addPackageTxs(int &nPackagesSelected, int &nDescendantsUpdated) EXCLUSIVE_LOCKS_REQUIRED(mempool.cs);
  
      // helper functions for addPackageTxs()
      /** Remove confirmed (inBlock) entries from given set */
      void onlyUnconfirmed(CTxMemPool::setEntries& testSet);
      /** Test if a new package would "fit" in the block */
      bool TestPackage(uint64_t packageSize, int64_t packageSigOpsCost) const;
      /** Perform checks on each transaction in a package:
        * locktime, premature-witness, serialized size (if necessary)
        * These checks should always succeed, and they're here
        * only as an extra check in case of suboptimal node configuration */
      bool TestPackageTransactions(const CTxMemPool::setEntries& package);
      /** Return true if given transaction from mapTx has already been evaluated,
        * or if the transaction's cached data in mapTx is incorrect. */
      bool SkipMapTxEntry(CTxMemPool::txiter it, indexed_modified_transaction_set &mapModifiedTx, CTxMemPool::setEntries &failedTx) EXCLUSIVE_LOCKS_REQUIRED(mempool.cs);
      /** Sort the package in an order that is valid to appear in a block */
      void SortForBlock(const CTxMemPool::setEntries& package, std::vector<CTxMemPool::txiter>& sortedEntries);
      /** Add descendants of given transactions to mapModifiedTx with ancestor
        * state updated assuming given transactions are inBlock. Returns number
        * of updated descendants. */
      int UpdatePackagesForAdded(const CTxMemPool::setEntries& alreadyAdded, indexed_modified_transaction_set &mapModifiedTx) EXCLUSIVE_LOCKS_REQUIRED(mempool.cs);
  };
  
  /** Modify the extranonce in a block */
  void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned int& nExtraNonce);
  int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev);
  
  #endif // BITCOIN_MINER_H
  