Improve startup performance, shutdown reliability, and Qt5 compatibility

- Defer SecureMsgStart and ReacceptWalletTransactions to background thread
  so GUI appears faster during startup
- Add shutdown checks in wallet scan/reaccept to prevent hanging on exit
- Smart wallet rescan: start from wallet birthday instead of genesis block
- Raise default dbcache from 25 to 128 MB for better performance
- Replace deprecated QDesktopServices with QStandardPaths (Qt5 compat)
- Enforce Qt5+ requirement in build system, remove -fpermissive flag

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/db.cpp

@@ -79,7 +79,7 @@ bool CDBEnv::Open(fs::path pathEnv_)
     if (GetBoolArg("-privdb", true))
         nEnvFlags |= DB_PRIVATE;
 
-    int nDbCache = GetArg("-dbcache", 25);
+    int nDbCache = GetArg("-dbcache", 128);
     dbenv.set_lg_dir(pathLogDir.string().c_str());
     dbenv.set_cachesize(nDbCache / 1024, (nDbCache % 1024)*1048576, 1);
     dbenv.set_lg_bsize(1048576);
@@ -593,4 +593,3 @@ bool CAddrDB::Read(CAddrMan& addr)
 
     return true;
 }
-

src/init.cpp

@@ -38,6 +38,9 @@ unsigned int nDerivationMethodIndex;
 bool fUseFastIndex;
 enum Checkpoints::CPMode CheckpointsMode;
 
+static CCriticalSection cs_DeferredStartup;
+static bool fDeferredStartupRunning = false;
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // Shutdown
@@ -69,6 +72,46 @@ bool ShutdownRequested()
     return fRequestShutdown;
 }
 
+void ThreadDeferredStartup(void* parg)
+{
+    // Make this thread recognisable as the deferred startup worker.
+    RenameThread("Triangles-postinit");
+
+    int64_t nTotalStart = GetTimeMillis();
+    printf("Starting deferred startup tasks...\n");
+    try
+    {
+        if (!fShutdown)
+        {
+            int64_t nStart = GetTimeMillis();
+            SecureMsgStart(fNoSmsg, GetBoolArg("-smsgscanchain"));
+            printf(" securemsg   %15"PRId64"ms\n", GetTimeMillis() - nStart);
+        }
+
+        if (!fShutdown && pwalletMain)
+        {
+            int64_t nStart = GetTimeMillis();
+            pwalletMain->ReacceptWalletTransactions();
+            printf(" reaccept    %15"PRId64"ms\n", GetTimeMillis() - nStart);
+        }
+
+        printf("Deferred startup tasks finished %"PRId64"ms\n", GetTimeMillis() - nTotalStart);
+    }
+    catch (std::exception& e)
+    {
+        PrintExceptionContinue(&e, "ThreadDeferredStartup()");
+    }
+    catch (...)
+    {
+        PrintExceptionContinue(NULL, "ThreadDeferredStartup()");
+    }
+
+    {
+        LOCK(cs_DeferredStartup);
+        fDeferredStartupRunning = false;
+    }
+}
+
 void Shutdown(void* parg)
 {
     static CCriticalSection cs_Shutdown;
@@ -90,7 +133,19 @@ void Shutdown(void* parg)
     if (fFirstThread)
     {
         fShutdown = true;
-        
+        int64_t nDeferredWaitStart = GetTimeMillis();
+        while (true)
+        {
+            bool fDeferredRunning;
+            {
+                LOCK(cs_DeferredStartup);
+                fDeferredRunning = fDeferredStartupRunning;
+            }
+            if (!fDeferredRunning || GetTimeMillis() - nDeferredWaitStart > 5000)
+                break;
+            MilliSleep(50);
+        }
+
         SecureMsgShutdown();
         
         nTransactionsUpdated++;
@@ -921,10 +976,6 @@ bool AppInit2()
            addrman.size(), GetTimeMillis() - nStart);
     
     
-    // ********************************************************* Step 10.1: startup secure messaging
-    
-    SecureMsgStart(fNoSmsg, GetBoolArg("-smsgscanchain"));
-    
     // ********************************************************* Step 11: start node
 
     if (!CheckDiskSpace())
@@ -945,6 +996,16 @@ bool AppInit2()
     if (fServer)
         NewThread(ThreadRPCServer, NULL);
 
+    {
+        LOCK(cs_DeferredStartup);
+        fDeferredStartupRunning = true;
+    }
+    if (!NewThread(ThreadDeferredStartup, NULL))
+    {
+        printf("Warning: deferred startup thread could not be started, running inline\n");
+        ThreadDeferredStartup(NULL);
+    }
+
     // ********************************************************* Step 12: finished
 
     uiInterface.InitMessage(_("Done loading"));
@@ -953,9 +1014,6 @@ bool AppInit2()
     if (!strErrors.str().empty())
         return InitError(strErrors.str());
 
-     // Add wallet transactions that aren't already in a block to mapTransactions
-    pwalletMain->ReacceptWalletTransactions();
-
 #if !defined(QT_GUI)
     // Loop until process is exit()ed from shutdown() function,
     // called from ThreadRPCServer thread when a "stop" command is received.
@@ -965,5 +1023,3 @@ bool AppInit2()
 
     return true;
 }
-
-

src/qt/guiutil.cpp

@@ -16,7 +16,7 @@
 #include <QApplication>
 #include <QClipboard>
 #include <QFileDialog>
-#include <QDesktopServices>
+#include <QStandardPaths>
 #include <QThread>
 
 #include <boost/filesystem.hpp>
@@ -172,7 +172,7 @@ QString getSaveFileName(QWidget *parent, const QString &caption,
     QString myDir;
     if(dir.isEmpty()) // Default to user documents location
     {
-        myDir = QDesktopServices::storageLocation(QDesktopServices::DocumentsLocation);
+        myDir = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
     }
     else
     {

src/qt/trianglesgui.cpp

@@ -64,7 +64,7 @@
 #include <QDateTime>
 #include <QMovie>
 #include <QFileDialog>
-#include <QDesktopServices>
+#include <QStandardPaths>
 #include <QTimer>
 #include <QDragEnterEvent>
 #if QT_VERSION < 0x050000
@@ -1368,7 +1368,7 @@ void TrianglesGUI::encryptWallet(bool status)
 
 void TrianglesGUI::backupWallet()
 {
-    QString saveDir = QDesktopServices::storageLocation(QDesktopServices::DocumentsLocation);
+    QString saveDir = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
     QString filename = QFileDialog::getSaveFileName(this, tr("Backup Wallet"), saveDir, tr("Wallet Data (*.dat)"));
     if(!filename.isEmpty()) {
         if(!walletModel->backupWallet(filename)) {

src/txdb-leveldb.cpp

@@ -28,7 +28,7 @@ leveldb::DB *txdb; // global pointer for LevelDB object instance
 
 static leveldb::Options GetOptions() {
     leveldb::Options options;
-    int nCacheSizeMB = GetArg("-dbcache", 25);
+    int nCacheSizeMB = GetArg("-dbcache", 128);
     options.block_cache = leveldb::NewLRUCache(nCacheSizeMB * 1048576);
     options.filter_policy = leveldb::NewBloomFilterPolicy(10);
     return options;

src/wallet.cpp

@@ -33,6 +33,36 @@ struct CompareValueOnly
     }
 };
 
+static CBlockIndex* GetWalletRescanStart(const CWallet& wallet)
+{
+    CBlockIndex* pindexStart = pindexGenesisBlock;
+
+    if (wallet.fFileBacked)
+    {
+        CWalletDB walletdb(wallet.strWalletFile);
+        CBlockLocator locator;
+        if (walletdb.ReadBestBlock(locator))
+        {
+            CBlockIndex* pindexLocator = locator.GetBlockIndex();
+            if (pindexLocator)
+                pindexStart = pindexLocator;
+        }
+    }
+
+    if (wallet.nTimeFirstKey > 1 && pindexBest)
+    {
+        int64_t nTimeWindowStart = wallet.nTimeFirstKey - 7200;
+        CBlockIndex* pindexBirthday = pindexBest;
+        while (pindexBirthday->pprev && pindexBirthday->GetBlockTime() > nTimeWindowStart)
+            pindexBirthday = pindexBirthday->pprev;
+
+        if (!pindexStart || pindexBirthday->nHeight < pindexStart->nHeight)
+            pindexStart = pindexBirthday;
+    }
+
+    return pindexStart ? pindexStart : pindexGenesisBlock;
+}
+
 CPubKey CWallet::GenerateNewKey()
 {
     bool fCompressed = CanSupportFeature(FEATURE_COMPRPUBKEY); // default to compressed public keys if we want 0.6.0 wallets
@@ -875,6 +905,9 @@ int CWallet::ScanForWalletTransactions(CBlockIndex* pindexStart, bool fUpdate)
         LOCK(cs_wallet);
         while (pindex)
         {
+            if (fShutdown)
+                break;
+
             // no need to read and scan block, if block was created before
             // our wallet birthday (as adjusted for block time variability)
             if (nTimeFirstKey && (pindex->nTime < (nTimeFirstKey - 7200))) {
@@ -910,54 +943,67 @@ void CWallet::ReacceptWalletTransactions()
     bool fRepeat = true;
     while (fRepeat)
     {
-        LOCK(cs_wallet);
+        if (fShutdown)
+            break;
+
         fRepeat = false;
         vector<CDiskTxPos> vMissingTx;
-        BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
         {
-            CWalletTx& wtx = item.second;
-            if ((wtx.IsCoinBase() && wtx.IsSpent(0)) || (wtx.IsCoinStake() && wtx.IsSpent(1)))
-                continue;
-
-            CTxIndex txindex;
-            bool fUpdated = false;
-            if (txdb.ReadTxIndex(wtx.GetHash(), txindex))
+            LOCK(cs_wallet);
+            BOOST_FOREACH(PAIRTYPE(const uint256, CWalletTx)& item, mapWallet)
             {
-                // Update fSpent if a tx got spent somewhere else by a copy of wallet.dat
-                if (txindex.vSpent.size() != wtx.vout.size())
-                {
-                    printf("ERROR: ReacceptWalletTransactions() : txindex.vSpent.size() %"PRIszu" != wtx.vout.size() %"PRIszu"\n", txindex.vSpent.size(), wtx.vout.size());
+                if (fShutdown)
+                    break;
+
+                CWalletTx& wtx = item.second;
+                if ((wtx.IsCoinBase() && wtx.IsSpent(0)) || (wtx.IsCoinStake() && wtx.IsSpent(1)))
                     continue;
-                }
-                for (unsigned int i = 0; i < txindex.vSpent.size(); i++)
+
+                CTxIndex txindex;
+                bool fUpdated = false;
+                if (txdb.ReadTxIndex(wtx.GetHash(), txindex))
                 {
-                    if (wtx.IsSpent(i))
-                        continue;
-                    if (!txindex.vSpent[i].IsNull() && IsMine(wtx.vout[i]))
+                    // Update fSpent if a tx got spent somewhere else by a copy of wallet.dat
+                    if (txindex.vSpent.size() != wtx.vout.size())
                     {
-                        wtx.MarkSpent(i);
-                        fUpdated = true;
-                        vMissingTx.push_back(txindex.vSpent[i]);
+                        printf("ERROR: ReacceptWalletTransactions() : txindex.vSpent.size() %"PRIszu" != wtx.vout.size() %"PRIszu"\n", txindex.vSpent.size(), wtx.vout.size());
+                        continue;
+                    }
+                    for (unsigned int i = 0; i < txindex.vSpent.size(); i++)
+                    {
+                        if (wtx.IsSpent(i))
+                            continue;
+                        if (!txindex.vSpent[i].IsNull() && IsMine(wtx.vout[i]))
+                        {
+                            wtx.MarkSpent(i);
+                            fUpdated = true;
+                            vMissingTx.push_back(txindex.vSpent[i]);
+                        }
+                    }
+                    if (fUpdated)
+                    {
+                        printf("ReacceptWalletTransactions found spent coin %s SUM %s\n", FormatMoney(wtx.GetCredit()).c_str(), wtx.GetHash().ToString().c_str());
+                        wtx.MarkDirty();
+                        wtx.WriteToDisk();
                     }
                 }
-                if (fUpdated)
+                else
                 {
-                    printf("ReacceptWalletTransactions found spent coin %s SUM %s\n", FormatMoney(wtx.GetCredit()).c_str(), wtx.GetHash().ToString().c_str());
-                    wtx.MarkDirty();
-                    wtx.WriteToDisk();
+                    // Re-accept any txes of ours that aren't already in a block
+                    if (!(wtx.IsCoinBase() || wtx.IsCoinStake()))
+                        wtx.AcceptWalletTransaction(txdb);
                 }
             }
-            else
-            {
-                // Re-accept any txes of ours that aren't already in a block
-                if (!(wtx.IsCoinBase() || wtx.IsCoinStake()))
-                    wtx.AcceptWalletTransaction(txdb);
-            }
         }
         if (!vMissingTx.empty())
         {
-            // TODO: optimize this to scan just part of the block chain?
-            if (ScanForWalletTransactions(pindexGenesisBlock))
+            if (fShutdown)
+                break;
+
+            CBlockIndex* pindexStart = GetWalletRescanStart(*this);
+            if (pindexStart)
+                printf("ReacceptWalletTransactions rescanning from block %d\n", pindexStart->nHeight);
+            if (ScanForWalletTransactions(pindexStart))
                 fRepeat = true;  // Found missing transactions: re-do re-accept.
         }
     }

triangles-qt.pro

@@ -7,13 +7,13 @@ DEFINES += QT_GUI BOOST_THREAD_USE_LIB BOOST_SPIRIT_THREADSAFE BOOST_THREAD_PROV
 CONFIG += no_include_pwd
 CONFIG += thread
 
-QMAKE_CXXFLAGS = -fpermissive
-
-greaterThan(QT_MAJOR_VERSION, 4) {
-    QT += widgets
-    DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0
+lessThan(QT_MAJOR_VERSION, 5) {
+    error(Triangles Qt requires Qt 5 or newer)
 }
 
+QT += widgets
+DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0
+
 # UNCOMMENT THIS SECTION TO BUILD ON WINDOWS
 # MSYS2 MinGW64 paths
 win32 {