assertion in CBlock::SetBestChainInner was too strong

[novacoin.git] / src / main.cpp

diff --git a/src/main.cpp b/src/main.cpp
index 9951952..1209f6e 100644 (file)
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -976,8 +976,10 @@ bool CTransaction::DisconnectInputs(CTxDB& txdb)
     }
 
     // Remove transaction from index
-    if (!txdb.EraseTxIndex(*this))
-        return error("DisconnectInputs() : EraseTxPos failed");
+    // This can fail if a duplicate of this transaction was in a chain that got
+    // reorganized away. This is only possible if this transaction was completely
+    // spent, so erasing it would be a no-op anway.
+    txdb.EraseTxIndex(*this);
 
     return true;
 }
@@ -1256,6 +1258,26 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex)
     if (!CheckBlock())
         return false;
 
+    // Do not allow blocks that contain transactions which 'overwrite' older transactions,
+    // unless those are already completely spent.
+    // If such overwrites are allowed, coinbases and transactions depending upon those
+    // can be duplicated to remove the ability to spend the first instance -- even after
+    // being sent to another address.
+    // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
+    // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
+    // already refuses previously-known transaction id's entirely.
+    // This rule applies to all blocks whose timestamp is after March 15, 2012, 0:00 UTC.
+    // On testnet it is enabled as of februari 20, 2012, 0:00 UTC.
+    if (pindex->nTime > 1331769600 || (fTestNet && pindex->nTime > 1329696000))
+        BOOST_FOREACH(CTransaction& tx, vtx)
+        {
+            CTxIndex txindexOld;
+            if (txdb.ReadTxIndex(tx.GetHash(), txindexOld))
+                BOOST_FOREACH(CDiskTxPos &pos, txindexOld.vSpent)
+                    if (pos.IsNull())
+                        return false;
+        }
+
     // To avoid being on the short end of a block-chain split,
     // don't do secondary validation of pay-to-script-hash transactions
     // until blocks with timestamps after paytoscripthashtime (see init.cpp for default).
@@ -1435,6 +1457,31 @@ runCommand(std::string strCommand)
         printf("runCommand error: system(%s) returned %d\n", strCommand.c_str(), nErr);
 }
 
+// Called from inside SetBestChain: attaches a block to the new best chain being built
+bool CBlock::SetBestChainInner(CTxDB& txdb, CBlockIndex *pindexNew)
+{
+    uint256 hash = GetHash();
+
+    // Adding to current best branch
+    if (!ConnectBlock(txdb, pindexNew) || !txdb.WriteHashBestChain(hash))
+    {
+        txdb.TxnAbort();
+        InvalidChainFound(pindexNew);
+        return false;
+    }
+    if (!txdb.TxnCommit())
+        return error("SetBestChain() : TxnCommit failed");
+
+    // Add to current best branch
+    pindexNew->pprev->pnext = pindexNew;
+
+    // Delete redundant memory transactions
+    BOOST_FOREACH(CTransaction& tx, vtx)
+        tx.RemoveFromMemoryPool();
+
+    return true;
+}
+
 bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
 {
     uint256 hash = GetHash();
@@ -1449,32 +1496,50 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
     }
     else if (hashPrevBlock == hashBestChain)
     {
-        // Adding to current best branch
-        if (!ConnectBlock(txdb, pindexNew) || !txdb.WriteHashBestChain(hash))
+        if (!SetBestChainInner(txdb, pindexNew))
+            return error("SetBestChain() : SetBestChainInner failed");
+    }
+    else
+    {
+        // the first block in the new chain that will cause it to become the new best chain
+        CBlockIndex *pindexIntermediate = pindexNew;
+
+        // list of blocks that need to be connected afterwards
+        std::vector<CBlockIndex*> vpindexSecondary;
+
+        // Reorganize is costly in terms of db load, as it works in a single db transaction.
+        // Try to limit how much needs to be done inside
+        while (pindexIntermediate->pprev && pindexIntermediate->pprev->bnChainWork > pindexBest->bnChainWork)
         {
-            txdb.TxnAbort();
-            InvalidChainFound(pindexNew);
-            return error("SetBestChain() : ConnectBlock failed");
+            vpindexSecondary.push_back(pindexIntermediate);
+            pindexIntermediate = pindexIntermediate->pprev;
         }
-        if (!txdb.TxnCommit())
-            return error("SetBestChain() : TxnCommit failed");
 
-        // Add to current best branch
-        pindexNew->pprev->pnext = pindexNew;
+        if (!vpindexSecondary.empty())
+            printf("Postponing %i reconnects\n", vpindexSecondary.size());
 
-        // Delete redundant memory transactions
-        BOOST_FOREACH(CTransaction& tx, vtx)
-            tx.RemoveFromMemoryPool();
-    }
-    else
-    {
-        // New best branch
-        if (!Reorganize(txdb, pindexNew))
+        // Switch to new best branch
+        if (!Reorganize(txdb, pindexIntermediate))
         {
             txdb.TxnAbort();
             InvalidChainFound(pindexNew);
             return error("SetBestChain() : Reorganize failed");
         }
+
+        // Connect futher blocks
+        BOOST_REVERSE_FOREACH(CBlockIndex *pindex, vpindexSecondary)
+        {
+            CBlock block;
+            if (!block.ReadFromDisk(pindex))
+            {
+                printf("SetBestChain() : ReadFromDisk failed\n");
+                break;
+            }
+            txdb.TxnBegin();
+            // errors now are not fatal, we still did a reorganisation to a new chain in a valid way
+            if (!block.SetBestChainInner(txdb, pindex))
+                break;
+        }
     }
 
     // Update best block in wallet (so we can detect restored wallets)