Use a signal to continue init after genesis activation

src/init.cpp

@@ -521,6 +521,21 @@ static void BlockNotifyCallback(bool initialSync, const CBlockIndex *pBlockIndex
     boost::thread t(runCommand, strCmd); // thread runs free
 }
 
+static bool fHaveGenesis = false;
+static boost::mutex cs_GenesisWait;
+static CConditionVariable condvar_GenesisWait;
+
+static void BlockNotifyGenesisWait(bool, const CBlockIndex *pBlockIndex)
+{
+    if (pBlockIndex != NULL) {
+        {
+            boost::unique_lock<boost::mutex> lock_GenesisWait(cs_GenesisWait);
+            fHaveGenesis = true;
+        }
+        condvar_GenesisWait.notify_all();
+    }
+}
+
 struct CImportingNow
 {
     CImportingNow() {
@@ -1454,6 +1469,14 @@ bool AppInit2(Config& config, boost::thread_group& threadGroup, CScheduler& sche
 
     // ********************************************************* Step 10: import blocks
 
+    // Either install a handler to notify us when genesis activates, or set fHaveGenesis directly.
+    // No locking, as this happens before any background thread is started.
+    if (chainActive.Tip() == NULL) {
+        uiInterface.NotifyBlockTip.connect(BlockNotifyGenesisWait);
+    } else {
+        fHaveGenesis = true;
+    }
+
     if (mapArgs.count("-blocknotify"))
         uiInterface.NotifyBlockTip.connect(BlockNotifyCallback);
 
@@ -1463,19 +1486,16 @@ bool AppInit2(Config& config, boost::thread_group& threadGroup, CScheduler& sche
         BOOST_FOREACH(const std::string& strFile, mapMultiArgs["-loadblock"])
             vImportFiles.push_back(strFile);
     }
+
     threadGroup.create_thread(boost::bind(&ThreadImport, vImportFiles));
 
     // Wait for genesis block to be processed
-    bool fHaveGenesis = false;
-    while (!fHaveGenesis && !fRequestShutdown) {
-        {
-            LOCK(cs_main);
-            fHaveGenesis = (chainActive.Tip() != NULL);
-        }
-
-        if (!fHaveGenesis) {
-            MilliSleep(10);
+    {
+        boost::unique_lock<boost::mutex> lock(cs_GenesisWait);
+        while (!fHaveGenesis) {
+            condvar_GenesisWait.wait(lock);
         }
+        uiInterface.NotifyBlockTip.disconnect(BlockNotifyGenesisWait);
     }
 
     // ********************************************************* Step 11: start node