Make sure that new stake modifier meets fixed generation interval.

[novacoin.git] / src / kernel.cpp

diff --git a/src/kernel.cpp b/src/kernel.cpp
index bd1cdf3..2484c3c 100644 (file)
--- a/src/kernel.cpp
+++ b/src/kernel.cpp
@@ -12,6 +12,15 @@ using namespace std;
 extern int nStakeMaxAge;
 extern int nStakeTargetSpacing;
 
+// Protocol switch time for fixed kernel modifier interval
+unsigned int nModifierSwitchTime  = 1413763200;    // Mon, 20 Oct 2014 00:00:00 GMT
+unsigned int nModifierTestSwitchTime = 1397520000; // Tue, 15 Apr 2014 00:00:00 GMT
+
+// Note: user must upgrade before the protocol switch deadline, otherwise it's required to
+//   re-download the blockchain. The timestamp of upgrade is recorded in the blockchain 
+//   database.
+unsigned int nModifierUpgradeTime = 0;
+
 typedef std::map<int, unsigned int> MapModifierCheckpoints;
 
 // Hard checkpoints of stake modifiers to ensure they are deterministic
@@ -34,6 +43,12 @@ static std::map<int, unsigned int> mapStakeModifierCheckpointsTestNet =
         ( 0, 0x0e00670bu )
     ;
 
+// Whether the given block is subject to new modifier protocol
+bool IsFixedModifierInterval(unsigned int nTimeBlock)
+{
+    return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime));
+}
+
 // Get time weight
 int64 GetWeight(int64 nIntervalBeginning, int64 nIntervalEnd)
 {
@@ -135,15 +150,17 @@ static bool SelectBlockFromCandidates(vector<pair<int64, uint256> >& vSortedByTi
 // block. This is to make it difficult for an attacker to gain control of
 // additional bits in the stake modifier, even after generating a chain of
 // blocks.
-bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64& nStakeModifier, bool& fGeneratedStakeModifier)
+bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64& nStakeModifier, bool& fGeneratedStakeModifier)
 {
     nStakeModifier = 0;
     fGeneratedStakeModifier = false;
+    const CBlockIndex* pindexPrev = pindexCurrent->pprev;
     if (!pindexPrev)
     {
         fGeneratedStakeModifier = true;
         return true;  // genesis block's modifier is 0
     }
+
     // First find current stake modifier and its generation block time
     // if it's not old enough, return the same stake modifier
     int64 nModifierTime = 0;
@@ -151,10 +168,35 @@ bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64& nStakeModif
         return error("ComputeNextStakeModifier: unable to get last modifier");
     if (fDebug)
     {
-        printf("ComputeNextStakeModifier: prev modifier=0x%016"PRI64x" time=%s\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str());
+        printf("ComputeNextStakeModifier: prev modifier=0x%016"PRI64x" time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime);
     }
     if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval)
+    {
+        if (fDebug)
+        {
+            printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime());
+        }
         return true;
+    }
+    if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval)
+    {
+        // fixed interval protocol requires current block timestamp also be in a different modifier interval
+        if (IsFixedModifierInterval(pindexCurrent->nTime))
+        {
+            if (fDebug)
+            {
+                printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
+            }
+            return true;
+        }
+        else
+        {
+            if (fDebug)
+            {
+                printf("ComputeNextStakeModifier: old modifier at block %s not meeting fixed modifier interval: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->GetBlockHash().ToString().c_str(), pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime());
+            }
+        }
+    }
 
     // Sort candidate blocks by timestamp
     vector<pair<int64, uint256> > vSortedByTimestamp;