Remove network state wipe from UnloadBlockIndex.

UnloadBlockIndex is only used during init if we end up reindexing
to clear our block state so that we can start over. However, at
that time no connections have been brought up as CConnman hasn't
been started yet, so all of the network processing state logic is
empty when its called.

Additionally, the initialization of the recentRejects set is moved
to InitPeerLogic.

src/init.cpp

@@ -1100,6 +1100,10 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
         return false;
 #endif
     // ********************************************************* Step 6: network initialization
+    // Note that we absolutely cannot open any actual connections
+    // until the very end ("start node") as the UTXO/block state
+    // is not yet setup and may end up being set up twice if we
+    // need to reindex later.
 
     assert(!g_connman);
     g_connman = std::unique_ptr<CConnman>(new CConnman(GetRand(std::numeric_limits<uint64_t>::max()), GetRand(std::numeric_limits<uint64_t>::max())));

src/main.cpp

@@ -4272,6 +4272,9 @@ bool RewindBlockIndex(const CChainParams& params)
     return true;
 }
 
+// May NOT be used after any connections are up as much
+// of the peer-processing logic assumes a consistent
+// block index state
 void UnloadBlockIndex()
 {
     LOCK(cs_main);
@@ -4282,18 +4285,12 @@ void UnloadBlockIndex()
     mempool.clear();
     mapOrphanTransactions.clear();
     mapOrphanTransactionsByPrev.clear();
-    nSyncStarted = 0;
     mapBlocksUnlinked.clear();
     vinfoBlockFile.clear();
     nLastBlockFile = 0;
     nBlockSequenceId = 1;
-    mapBlockSource.clear();
-    mapBlocksInFlight.clear();
-    nPreferredDownload = 0;
     setDirtyBlockIndex.clear();
     setDirtyFileInfo.clear();
-    mapNodeState.clear();
-    recentRejects.reset(NULL);
     versionbitscache.Clear();
     for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
         warningcache[b].clear();
@@ -4318,9 +4315,6 @@ bool InitBlockIndex(const CChainParams& chainparams)
 {
     LOCK(cs_main);
 
-    // Initialize global variables that cannot be constructed at startup.
-    recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
-
     // Check whether we're already initialized
     if (chainActive.Genesis() != NULL)
         return true;
@@ -4709,6 +4703,11 @@ std::string GetWarnings(const std::string& strFor)
 // blockchain -> download logic notification
 //
 
+PeerLogicValidation::PeerLogicValidation(CConnman* connmanIn) : connman(connmanIn) {
+    // Initialize global variables that cannot be constructed at startup.
+    recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
+}
+
 void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) {
     const int nNewHeight = pindexNew->nHeight;
     connman->SetBestHeight(nNewHeight);

src/main.h

@@ -542,7 +542,7 @@ class PeerLogicValidation : public CValidationInterface {
     CConnman* connman;
 
 public:
-    PeerLogicValidation(CConnman* connmanIn) : connman(connmanIn) {}
+    PeerLogicValidation(CConnman* connmanIn);
 
     virtual void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload);
     virtual void BlockChecked(const CBlock& block, const CValidationState& state);