getblocktemplate: longpolling support

src/main.cpp

@@ -41,6 +41,8 @@ CCriticalSection cs_main;
 map<uint256, CBlockIndex*> mapBlockIndex;
 CChain chainActive;
 int64_t nTimeBestReceived = 0;
+CWaitableCriticalSection csBestBlock;
+CConditionVariable cvBlockChange;
 int nScriptCheckThreads = 0;
 bool fImporting = false;
 bool fReindex = false;
@@ -1944,11 +1946,14 @@ void static UpdateTip(CBlockIndex *pindexNew) {
     // New best block
     nTimeBestReceived = GetTime();
     mempool.AddTransactionsUpdated(1);
+
     LogPrintf("UpdateTip: new best=%s  height=%d  log2_work=%.8g  tx=%lu  date=%s progress=%f\n",
       chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(), log(chainActive.Tip()->nChainWork.getdouble())/log(2.0), (unsigned long)chainActive.Tip()->nChainTx,
       DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
       Checkpoints::GuessVerificationProgress(chainActive.Tip()));
 
+    cvBlockChange.notify_all();
+
     // Check the version of the last 100 blocks to see if we need to upgrade:
     if (!fIsInitialDownload)
     {