PPCoin: coin age; main chain protocol switches to sum(coin age spent)

diff --git a/src/bignum.h b/src/bignum.h
index 1a2406b..5c08c58 100644 (file)
--- a/src/bignum.h
+++ b/src/bignum.h
@@ -182,6 +182,21 @@ public:
         BN_mpi2bn(pch, p - pch, this);
     }
 
+    uint64 getuint64()
+    {
+        unsigned int nSize = BN_bn2mpi(this, NULL);
+        if (nSize < 4)
+            return 0;
+        std::vector<unsigned char> vch(nSize);
+        BN_bn2mpi(this, &vch[0]);
+        if (vch.size() > 4)
+            vch[4] &= 0x7f;
+        uint64 n = 0;
+        for (int i = 0, j = vch.size()-1; i < sizeof(n) && j >= 4; i++, j--)
+            ((unsigned char*)&n)[i] = vch[j];
+        return n;
+    }
+
     void setuint256(uint256 n)
     {
         unsigned char pch[sizeof(n) + 6];

diff --git a/src/db.cpp b/src/db.cpp
index 9ac93b3..bb3c3b0 100644 (file)
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -1,5 +1,6 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2011 The Bitcoin developers
+// Copyright (c) 2011 The PPCoin developers
 // Distributed under the MIT/X11 software license, see the accompanying
 // file license.txt or http://www.opensource.org/licenses/mit-license.php.
 
@@ -458,14 +459,14 @@ bool CTxDB::WriteHashBestChain(uint256 hashBestChain)
     return Write(string("hashBestChain"), hashBestChain);
 }
 
-bool CTxDB::ReadBestInvalidWork(CBigNum& bnBestInvalidWork)
+bool CTxDB::ReadBestInvalidTrust(uint64& nBestInvalidTrust)
 {
-    return Read(string("bnBestInvalidWork"), bnBestInvalidWork);
+    return Read(string("nBestInvalidTrust"), nBestInvalidTrust);
 }
 
-bool CTxDB::WriteBestInvalidWork(CBigNum bnBestInvalidWork)
+bool CTxDB::WriteBestInvalidTrust(uint64 nBestInvalidTrust)
 {
-    return Write(string("bnBestInvalidWork"), bnBestInvalidWork);
+    return Write(string("nBestInvalidTrust"), nBestInvalidTrust);
 }
 
 CBlockIndex static * InsertBlockIndex(uint256 hash)
@@ -525,6 +526,7 @@ bool CTxDB::LoadBlockIndex()
             pindexNew->pnext          = InsertBlockIndex(diskindex.hashNext);
             pindexNew->nFile          = diskindex.nFile;
             pindexNew->nBlockPos      = diskindex.nBlockPos;
+            pindexNew->nChainTrust    = diskindex.nChainTrust;
             pindexNew->nHeight        = diskindex.nHeight;
             pindexNew->nVersion       = diskindex.nVersion;
             pindexNew->hashMerkleRoot = diskindex.hashMerkleRoot;
@@ -546,21 +548,6 @@ bool CTxDB::LoadBlockIndex()
     }
     pcursor->close();
 
-    // Calculate bnChainWork
-    vector<pair<int, CBlockIndex*> > vSortedByHeight;
-    vSortedByHeight.reserve(mapBlockIndex.size());
-    BOOST_FOREACH(const PAIRTYPE(uint256, CBlockIndex*)& item, mapBlockIndex)
-    {
-        CBlockIndex* pindex = item.second;
-        vSortedByHeight.push_back(make_pair(pindex->nHeight, pindex));
-    }
-    sort(vSortedByHeight.begin(), vSortedByHeight.end());
-    BOOST_FOREACH(const PAIRTYPE(int, CBlockIndex*)& item, vSortedByHeight)
-    {
-        CBlockIndex* pindex = item.second;
-        pindex->bnChainWork = (pindex->pprev ? pindex->pprev->bnChainWork : 0) + pindex->GetBlockWork();
-    }
-
     // Load hashBestChain pointer to end of best chain
     if (!ReadHashBestChain(hashBestChain))
     {
@@ -572,11 +559,11 @@ bool CTxDB::LoadBlockIndex()
         return error("CTxDB::LoadBlockIndex() : hashBestChain not found in the block index");
     pindexBest = mapBlockIndex[hashBestChain];
     nBestHeight = pindexBest->nHeight;
-    bnBestChainWork = pindexBest->bnChainWork;
+    nBestChainTrust = pindexBest->nChainTrust;
     printf("LoadBlockIndex(): hashBestChain=%s  height=%d\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight);
 
-    // Load bnBestInvalidWork, OK if it doesn't exist
-    ReadBestInvalidWork(bnBestInvalidWork);
+    // Load nBestInvalidTrust, OK if it doesn't exist
+    ReadBestInvalidTrust(nBestInvalidTrust);
 
     // Verify blocks in the best chain
     CBlockIndex* pindexFork = NULL;

diff --git a/src/db.h b/src/db.h
index 15bfb29..578a497 100644 (file)
--- a/src/db.h
+++ b/src/db.h
@@ -1,5 +1,6 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2011 The Bitcoin developers
+// Copyright (c) 2011 The PPCoin developers
 // Distributed under the MIT/X11 software license, see the accompanying
 // file license.txt or http://www.opensource.org/licenses/mit-license.php.
 #ifndef BITCOIN_DB_H
@@ -288,8 +289,8 @@ public:
     bool EraseBlockIndex(uint256 hash);
     bool ReadHashBestChain(uint256& hashBestChain);
     bool WriteHashBestChain(uint256 hashBestChain);
-    bool ReadBestInvalidWork(CBigNum& bnBestInvalidWork);
-    bool WriteBestInvalidWork(CBigNum bnBestInvalidWork);
+    bool ReadBestInvalidTrust(uint64& nBestInvalidTrust);
+    bool WriteBestInvalidTrust(uint64 nBestInvalidTrust);
     bool LoadBlockIndex();
 };
 

diff --git a/src/main.cpp b/src/main.cpp
index caeb961..9df7584 100644 (file)
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -34,8 +34,8 @@ static CBigNum bnProofOfWorkLimit(~uint256(0) >> 32);
 const int nInitialBlockThreshold = 120; // Regard blocks up until N-threshold as "initial download"
 CBlockIndex* pindexGenesisBlock = NULL;
 int nBestHeight = -1;
-CBigNum bnBestChainWork = 0;
-CBigNum bnBestInvalidWork = 0;
+uint64 nBestChainTrust = 0;
+uint64 nBestInvalidTrust = 0;
 uint256 hashBestChain = 0;
 CBlockIndex* pindexBest = NULL;
 int64 nTimeBestReceived = 0;
@@ -744,15 +744,15 @@ bool IsInitialBlockDownload()
 
 void static InvalidChainFound(CBlockIndex* pindexNew)
 {
-    if (pindexNew->bnChainWork > bnBestInvalidWork)
+    if (pindexNew->nChainTrust > nBestInvalidTrust)
     {
-        bnBestInvalidWork = pindexNew->bnChainWork;
-        CTxDB().WriteBestInvalidWork(bnBestInvalidWork);
+        nBestInvalidTrust = pindexNew->nChainTrust;
+        CTxDB().WriteBestInvalidTrust(nBestInvalidTrust);
         MainFrameRepaint();
     }
-    printf("InvalidChainFound: invalid block=%s  height=%d  work=%s\n", pindexNew->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->nHeight, pindexNew->bnChainWork.ToString().c_str());
-    printf("InvalidChainFound:  current best=%s  height=%d  work=%s\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, bnBestChainWork.ToString().c_str());
-    if (pindexBest && bnBestInvalidWork > bnBestChainWork + pindexBest->GetBlockWork() * 6)
+    printf("InvalidChainFound: invalid block=%s  height=%d  trust=%s\n", pindexNew->GetBlockHash().ToString().substr(0,20).c_str(), pindexNew->nHeight, CBigNum(pindexNew->nChainTrust).ToString().c_str());
+    printf("InvalidChainFound:  current best=%s  height=%d  trust=%s\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, CBigNum(nBestChainTrust).ToString().c_str());
+    if (pindexBest && nBestInvalidTrust > nBestChainTrust + pindexBest->GetBlockTrust() * 6)
         printf("InvalidChainFound: WARNING: Displayed transactions may not be correct!  You may need to upgrade, or other nodes may need to upgrade.\n");
 }
 
@@ -860,6 +860,10 @@ bool CTransaction::ConnectInputs(CTxDB& txdb, map<uint256, CTxIndex>& mapTestPoo
                     if (pindex->nBlockPos == txindex.pos.nBlockPos && pindex->nFile == txindex.pos.nFile)
                         return error("ConnectInputs() : tried to spend coinbase at depth %d", pindexBlock->nHeight - pindex->nHeight);
 
+            // ppcoin: check transaction timestamp
+            if (txPrev.nTime > nTime)
+                return DoS(100, error("ConnectInputs() : transaction timestamp earlier than input transaction"));
+
             // Skip ECDSA signature verification when connecting blocks (fBlock=true) during initial download
             // (before the last blockchain checkpoint). This is safe because block merkle hashes are
             // still computed and checked, and any change will be caught at the next checkpoint.
@@ -1178,15 +1182,59 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
     hashBestChain = hash;
     pindexBest = pindexNew;
     nBestHeight = pindexBest->nHeight;
-    bnBestChainWork = pindexNew->bnChainWork;
+    nBestChainTrust = pindexNew->nChainTrust;
     nTimeBestReceived = GetTime();
     nTransactionsUpdated++;
-    printf("SetBestChain: new best=%s  height=%d  work=%s\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, bnBestChainWork.ToString().c_str());
+    printf("SetBestChain: new best=%s  height=%d  trust=%s\n", hashBestChain.ToString().substr(0,20).c_str(), nBestHeight, CBigNum(nBestChainTrust).ToString().c_str());
 
     return true;
 }
 
 
+// ppcoin: total coin age spent in block, in the unit of coin-days.
+uint64 CBlock::GetBlockCoinAge()
+{
+    uint64 nCoinAge = 0;
+
+    BOOST_FOREACH(const CTransaction& tx, vtx)
+    {
+        if (tx.IsCoinBase())
+            continue;
+
+        BOOST_FOREACH(const CTxIn& txin, tx.vin)
+        {
+            // First try finding the previous transaction in database
+            CTransaction txPrev;
+            if (!txPrev.ReadFromDisk(txin.prevout))
+            {
+                // If database lookup fails try memory pool
+                CRITICAL_BLOCK(cs_mapTransactions)
+                {
+                    if (!mapTransactions.count(txin.prevout.hash))
+                        return 0; // Neither found in database nor memory pool
+                    txPrev = mapTransactions[txin.prevout.hash];
+                }
+            }
+
+            if (tx.nTime < txPrev.nTime)
+                return 0;  // Transaction timestamp violation
+
+            int64 nValueIn = txPrev.vout[txin.prevout.n].nValue;
+            CBigNum bnTxInCoinAge = CBigNum(nValueIn) * (tx.nTime - txPrev.nTime) / COIN / (24 * 60 * 60);
+            nCoinAge += bnTxInCoinAge.getuint64();
+
+            if (fDebug && GetBoolArg("-printcoinage"))
+                printf("coin age     nValueIn=%-12I64d nTimeDiff=%d nCoinAge=%"PRI64d"\n", nValueIn, tx.nTime - txPrev.nTime, nCoinAge);
+        }
+    }
+
+    if (!nCoinAge) 
+        nCoinAge = 1;
+
+    return nCoinAge;
+}
+
+
 bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
 {
     // Check for duplicate
@@ -1206,7 +1254,10 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
         pindexNew->pprev = (*miPrev).second;
         pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
     }
-    pindexNew->bnChainWork = (pindexNew->pprev ? pindexNew->pprev->bnChainWork : 0) + pindexNew->GetBlockWork();
+    uint64 nCoinAge = GetBlockCoinAge();
+    if (!nCoinAge)
+        return error("AddToBlockIndex() : invalid or orphaned transaction in block");
+    pindexNew->nChainTrust = (pindexNew->pprev ? pindexNew->pprev->nChainTrust : 0) + nCoinAge;
 
     CTxDB txdb;
     txdb.TxnBegin();
@@ -1215,7 +1266,7 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
         return false;
 
     // New best
-    if (pindexNew->bnChainWork > bnBestChainWork)
+    if (pindexNew->nChainTrust > nBestChainTrust)
         if (!SetBestChain(txdb, pindexNew))
             return false;
 
@@ -1661,7 +1712,7 @@ string GetWarnings(string strFor)
     }
 
     // Longer invalid proof-of-work chain
-    if (pindexBest && bnBestInvalidWork > bnBestChainWork + pindexBest->GetBlockWork() * 6)
+    if (pindexBest && nBestInvalidTrust > nBestChainTrust + pindexBest->GetBlockTrust() * 6)
     {
         nPriority = 2000;
         strStatusBar = strRPC = "WARNING: Displayed transactions may not be correct!  You may need to upgrade, or other nodes may need to upgrade.";

diff --git a/src/main.h b/src/main.h
index c02b5fb..32fbc39 100644 (file)
--- a/src/main.h
+++ b/src/main.h
@@ -56,8 +56,8 @@ extern std::map<uint256, CBlockIndex*> mapBlockIndex;
 extern uint256 hashGenesisBlock;
 extern CBlockIndex* pindexGenesisBlock;
 extern int nBestHeight;
-extern CBigNum bnBestChainWork;
-extern CBigNum bnBestInvalidWork;
+extern uint64 nBestChainTrust;
+extern uint64 nBestInvalidTrust;
 extern uint256 hashBestChain;
 extern CBlockIndex* pindexBest;
 extern unsigned int nTransactionsUpdated;
@@ -1003,6 +1003,7 @@ public:
     bool AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos);
     bool CheckBlock() const;
     bool AcceptBlock();
+    uint64 GetBlockCoinAge(); // ppcoin: calculate total coin age spent in block
 };
 
 
@@ -1026,8 +1027,8 @@ public:
     CBlockIndex* pnext;
     unsigned int nFile;
     unsigned int nBlockPos;
+    uint64 nChainTrust;// ppcoin: trust score of chain, in the unit of coin-days
     int nHeight;
-    CBigNum bnChainWork;
 
     // block header
     int nVersion;
@@ -1045,7 +1046,7 @@ public:
         nFile = 0;
         nBlockPos = 0;
         nHeight = 0;
-        bnChainWork = 0;
+        nChainTrust = 0;
 
         nVersion       = 0;
         hashMerkleRoot = 0;
@@ -1062,7 +1063,7 @@ public:
         nFile = nFileIn;
         nBlockPos = nBlockPosIn;
         nHeight = 0;
-        bnChainWork = 0;
+        nChainTrust = 0;
 
         nVersion       = block.nVersion;
         hashMerkleRoot = block.hashMerkleRoot;
@@ -1094,13 +1095,9 @@ public:
         return (int64)nTime;
     }
 
-    CBigNum GetBlockWork() const
+    int64 GetBlockTrust() const
     {
-        CBigNum bnTarget;
-        bnTarget.SetCompact(nBits);
-        if (bnTarget <= 0)
-            return 0;
-        return (CBigNum(1)<<256) / (bnTarget+1);
+        return (nChainTrust - pprev->nChainTrust);
     }
 
     bool IsInMainChain() const
@@ -1160,8 +1157,8 @@ public:
 
     std::string ToString() const
     {
-        return strprintf("CBlockIndex(nprev=%08x, pnext=%08x, nFile=%d, nBlockPos=%-6d nHeight=%d, merkle=%s, hashBlock=%s)",
-            pprev, pnext, nFile, nBlockPos, nHeight,
+        return strprintf("CBlockIndex(nprev=%08x, pnext=%08x, nFile=%d, nBlockPos=%-6d nChainTrust=%"PRI64d" nHeight=%d, merkle=%s, hashBlock=%s)",
+            pprev, pnext, nFile, nBlockPos, nChainTrust, nHeight,
             hashMerkleRoot.ToString().substr(0,10).c_str(),
             GetBlockHash().ToString().substr(0,20).c_str());
     }
@@ -1203,6 +1200,7 @@ public:
         READWRITE(hashNext);
         READWRITE(nFile);
         READWRITE(nBlockPos);
+        READWRITE(nChainTrust);
         READWRITE(nHeight);
 
         // block header