Add CMutableTransaction and make CTransaction immutable.

In addition, introduce a cached hash inside CTransaction, to prevent
recalculating it over and over again.

1 files changed, 11 insertions, 7 deletions

diff --git a/src/miner.cpp b/src/miner.cpp
index 7efca7cfff..37cdc7d840 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -86,14 +86,14 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
     CBlock *pblock = &pblocktemplate->block; // pointer for convenience
 
     // Create coinbase tx
-    CTransaction txNew;
+    CMutableTransaction txNew;
     txNew.vin.resize(1);
     txNew.vin[0].prevout.SetNull();
     txNew.vout.resize(1);
     txNew.vout[0].scriptPubKey = scriptPubKeyIn;
 
-    // Add our coinbase tx as first transaction
-    pblock->vtx.push_back(txNew);
+    // Add dummy coinbase tx as first transaction
+    pblock->vtx.push_back(CTransaction());
     pblocktemplate->vTxFees.push_back(-1); // updated at end
     pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 
@@ -294,7 +294,10 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
         nLastBlockSize = nBlockSize;
         LogPrintf("CreateNewBlock(): total size %u\n", nBlockSize);
 
-        pblock->vtx[0].vout[0].nValue = GetBlockValue(pindexPrev->nHeight+1, nFees);
+        // Compute final coinbase transaction.
+        txNew.vout[0].nValue = GetBlockValue(pindexPrev->nHeight+1, nFees);
+        txNew.vin[0].scriptSig = CScript() << OP_0 << OP_0;
+        pblock->vtx[0] = txNew;
         pblocktemplate->vTxFees[0] = -nFees;
 
         // Fill in header
@@ -302,7 +305,6 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
         UpdateTime(*pblock, pindexPrev);
         pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock);
         pblock->nNonce         = 0;
-        pblock->vtx[0].vin[0].scriptSig = CScript() << OP_0 << OP_0;
         pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 
         CBlockIndex indexDummy(*pblock);
@@ -328,9 +330,11 @@ void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int&
     }
     ++nExtraNonce;
     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
-    pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
-    assert(pblock->vtx[0].vin[0].scriptSig.size() <= 100);
+    CMutableTransaction txCoinbase(pblock->vtx[0]);
+    txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
+    assert(txCoinbase.vin[0].scriptSig.size() <= 100);
 
+    pblock->vtx[0] = txCoinbase;
     pblock->hashMerkleRoot = pblock->BuildMerkleTree();
 }