Refactor CreateNewBlock to be a method of the BlockAssembler class

src/miner.h

@@ -7,14 +7,17 @@
 #define BITCOIN_MINER_H
 
 #include "primitives/block.h"
+#include "txmempool.h"
 
 #include <stdint.h>
+#include <memory>
 
 class CBlockIndex;
 class CChainParams;
 class CReserveKey;
 class CScript;
 class CWallet;
+
 namespace Consensus { struct Params; };
 
 static const bool DEFAULT_PRINTPRIORITY = false;
@@ -27,7 +30,58 @@ struct CBlockTemplate
 };
 
 /** Generate a new block, without valid proof-of-work */
-CBlockTemplate* CreateNewBlock(const CChainParams& chainparams, const CScript& scriptPubKeyIn);
+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
+    unsigned int nBlockMaxSize, nBlockMinSize;
+
+    // Information on the current status of the block
+    uint64_t nBlockSize;
+    uint64_t nBlockTx;
+    unsigned int nBlockSigOps;
+    CAmount nFees;
+    CTxMemPool::setEntries inBlock;
+
+    // Chain context for the block
+    int nHeight;
+    int64_t nLockTimeCutoff;
+    const CChainParams& chainparams;
+
+    // Variables used for addScoreTxs and addPriorityTxs
+    int lastFewTxs;
+    bool blockFinished;
+
+public:
+    BlockAssembler(const CChainParams& chainparams);
+    /** Construct a new block template with coinbase to scriptPubKeyIn */
+    CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn);
+
+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 modified feerate */
+    void addScoreTxs();
+    /** Add transactions based on tx "priority" */
+    void addPriorityTxs();
+
+    // helper function for addScoreTxs and addPriorityTxs
+    /** Test if tx will still "fit" in the block */
+    bool TestForBlock(CTxMemPool::txiter iter);
+    /** Test if tx still has unconfirmed parents not yet in block */
+    bool isStillDependent(CTxMemPool::txiter iter);
+};
+
 /** 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);