PPCoin: Automatically select a checkpoint for 'sendcheckpoint'

[novacoin.git] / src / checkpoints.cpp

diff --git a/src/checkpoints.cpp b/src/checkpoints.cpp
index 4560240..097dd87 100644 (file)
--- a/src/checkpoints.cpp
+++ b/src/checkpoints.cpp
@@ -62,37 +62,60 @@ namespace Checkpoints
     CSyncCheckpoint checkpointMessagePending;
     CCriticalSection cs_hashSyncCheckpoint;
 
-    bool CSyncCheckpoint::ProcessSyncCheckpoint()
+    // ppcoin: only descendant of current sync-checkpoint is allowed
+    bool ValidateSyncCheckpoint(uint256 hashCheckpoint)
     {
-        if (!CheckSignature())
+        if (!mapBlockIndex.count(hashSyncCheckpoint))
+            return error("ValidateSyncCheckpoint: block index missing for current sync-checkpoint %s", hashSyncCheckpoint.ToString().c_str());
+        if (!mapBlockIndex.count(hashCheckpoint))
+            return error("ValidateSyncCheckpoint: block index missing for received sync-checkpoint %s", hashCheckpoint.ToString().c_str());
+
+        CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
+        CBlockIndex* pindexCheckpointRecv = mapBlockIndex[hashCheckpoint];
+        if (pindexCheckpointRecv->nHeight <= pindexSyncCheckpoint->nHeight)
+            return false;  // this is an older checkpoint, ignore
+
+        CBlockIndex* pindex = pindexCheckpointRecv;
+        while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
+            pindex = pindex->pprev;
+        if (pindex->GetBlockHash() != hashSyncCheckpoint)
+            return error("ValidateSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
+        return true;
+    }
+
+    bool AcceptPendingSyncCheckpoint(uint256 hashAcceptedBlock)
+    {
+        if (!mapBlockIndex.count(hashAcceptedBlock))
             return false;
 
         CRITICAL_BLOCK(cs_hashSyncCheckpoint)
-        {
-            if (!mapBlockIndex.count(hashCheckpoint))
+            if ((!checkpointMessagePending.IsNull()) && checkpointMessagePending.hashCheckpoint == hashAcceptedBlock)
             {
-                // TODO: we don't have this block yet, so ask for it
-                checkpointMessagePending = *this;
-                return false;
+                if (!ValidateSyncCheckpoint(checkpointMessagePending.hashCheckpoint))
+                {
+                    checkpointMessagePending.SetNull();
+                    return false;
+                }
+                hashSyncCheckpoint = checkpointMessagePending.hashCheckpoint;
+                checkpointMessage = checkpointMessagePending;
+                checkpointMessagePending.SetNull();
+                printf("AcceptPendingSyncCheckpoint : sync-checkpoint at %s\n", hashSyncCheckpoint.ToString().c_str());
+                // relay the checkpoint
+                BOOST_FOREACH(CNode* pnode, vNodes)
+                    checkpointMessage.RelayTo(pnode);
+                return true;
             }
 
-            if (!mapBlockIndex.count(hashSyncCheckpoint))
-                return error("ProcessSyncCheckpoint: block index missing for synchronized checkpoint %s", hashSyncCheckpoint.ToString().c_str());
-
-            CBlockIndex* pindexSyncCheckpoint = mapBlockIndex[hashSyncCheckpoint];
-            CBlockIndex* pindexCheckpointPending = mapBlockIndex[hashCheckpoint];
-            if (pindexCheckpointPending->nHeight <= pindexSyncCheckpoint->nHeight)
-                return false;  // this is an older checkpoint, ignore
+        return false;
+    }
 
-            CBlockIndex* pindex = pindexCheckpointPending;
-            while (pindex->nHeight > pindexSyncCheckpoint->nHeight)
-                pindex = pindex->pprev;
-            if (pindex->GetBlockHash() != hashSyncCheckpoint)
-                return error("ProcessSyncCheckpoint: new sync-checkpoint %s is not a descendant of current sync-checkpoint %s", hashCheckpoint.ToString().c_str(), hashSyncCheckpoint.ToString().c_str());
-            hashSyncCheckpoint = this->hashCheckpoint;
-            checkpointMessage = *this;
-        }
-        return true;
+    uint256 AutoSelectSyncCheckpoint()
+    {
+        // select block roughly 8 hours ago
+        CBlockIndex *pindex = mapBlockIndex[hashSyncCheckpoint];
+        while (pindex->pnext && pindex->pnext->GetBlockTime() + AUTO_CHECKPOINT_MIN_SPAN <= GetAdjustedTime())
+            pindex = pindex->pnext;
+        return pindex->GetBlockHash();
     }
 
     // ppcoin: automatic checkpoint (represented by height of checkpoint)
@@ -212,3 +235,31 @@ namespace Checkpoints
         return true;
     }
 }
+
+// ppcoin: process synchronized checkpoint
+bool CSyncCheckpoint::ProcessSyncCheckpoint(CNode* pfrom)
+{
+    if (!CheckSignature())
+        return false;
+
+    CRITICAL_BLOCK(Checkpoints::cs_hashSyncCheckpoint)
+    {
+        if (!mapBlockIndex.count(hashCheckpoint))
+        {
+            // We haven't accepted this block, keep the checkpoint as pending
+            Checkpoints::checkpointMessagePending = *this;
+            printf("ProcessSyncCheckpoint : pending for sync-checkpoint %s\n", hashCheckpoint.ToString().c_str());
+            // Ask this guy to fill in what we're missing
+            if (pfrom)
+                pfrom->PushGetBlocks(pindexBest, hashCheckpoint);
+            return false;
+        }
+        if (!Checkpoints::ValidateSyncCheckpoint(hashCheckpoint))
+            return false;
+        Checkpoints::hashSyncCheckpoint = this->hashCheckpoint;
+        Checkpoints::checkpointMessage = *this;
+        Checkpoints::checkpointMessagePending.SetNull();
+        printf("ProcessSyncCheckpoint : sync-checkpoint at %s\n", Checkpoints::hashSyncCheckpoint.ToString().c_str());
+    }
+    return true;
+}