Improve block database load error reporting

src/init.cpp

@@ -82,6 +82,7 @@ void Shutdown(void* parg)
     if (fFirstThread)
     {
         fShutdown = true;
+        fRequestShutdown = true;
         nTransactionsUpdated++;
         bitdb.Flush(false);
         {
@@ -791,9 +792,21 @@ bool AppInit2()
     nTotalCache -= nCoinDBCache;
     nCoinCacheSize = nTotalCache / 300; // coins in memory require around 300 bytes
 
+    bool fLoaded = false;
+    while (!fLoaded) {
+        bool fReset = fReindex;
+        std::string strLoadError;
+
         uiInterface.InitMessage(_("Loading block index..."));
 
         nStart = GetTimeMillis();
+        do {
+            try {
+                UnloadBlockIndex();
+                delete pcoinsTip;
+                delete pcoinsdbview;
+                delete pblocktree;
+
                 pblocktree = new CBlockTreeDB(nBlockTreeDBCache, false, fReindex);
                 pcoinsdbview = new CCoinsViewDB(nCoinDBCache, false, fReindex);
                 pcoinsTip = new CCoinsViewCache(*pcoinsdbview);
@@ -801,17 +814,47 @@ bool AppInit2()
                 if (fReindex)
                     pblocktree->WriteReindexing(true);
 
-    if (!LoadBlockIndex())
-        return InitError(_("Error loading block database"));
+                if (!LoadBlockIndex()) {
+                    strLoadError = _("Error loading block database");
+                    break;
+                }
 
                 // Initialize the block index (no-op if non-empty database was already loaded)
-    if (!InitBlockIndex())
-        return InitError(_("Error initializing block database"));
+                if (!InitBlockIndex()) {
+                    strLoadError = _("Error initializing block database");
+                    break;
+                }
 
                 uiInterface.InitMessage(_("Verifying block database integrity..."));
+                if (!VerifyDB()) {
+                    strLoadError = _("Corrupted block database detected");
+                    break;
+                }
+            } catch(std::exception &e) {
+                strLoadError = _("Error opening block database");
+                break;
+            }
+
+            fLoaded = true;
+        } while(false);
 
-    if (!VerifyDB())
-        return InitError(_("Corrupted block database detected. Please restart the client with -reindex."));
+        if (!fLoaded) {
+            // first suggest a reindex
+            if (!fReset) {
+                bool fRet = uiInterface.ThreadSafeMessageBox(
+                    strLoadError + ".\n" + _("Do you want to rebuild the block database now?"),
+                    "", CClientUIInterface::MSG_ERROR | CClientUIInterface::BTN_ABORT);
+                if (fRet) {
+                    fReindex = true;
+                    fRequestShutdown = false;
+                } else {
+                    return false;
+                }
+            } else {
+                return InitError(strLoadError);
+            }
+        }
+    }
 
     if (mapArgs.count("-txindex") && fTxIndex != GetBoolArg("-txindex", false))
         return InitError(_("You need to rebuild the databases using -reindex to change -txindex"));

src/main.cpp

@@ -2653,6 +2653,18 @@ bool VerifyDB() {
     return true;
 }
 
+void UnloadBlockIndex()
+{
+    mapBlockIndex.clear();
+    setBlockIndexValid.clear();
+    pindexGenesisBlock = NULL;
+    nBestHeight = 0;
+    bnBestChainWork = 0;
+    bnBestInvalidWork = 0;
+    hashBestChain = 0;
+    pindexBest = NULL;
+}
+
 bool LoadBlockIndex()
 {
     if (fTestNet)

src/main.h

@@ -139,6 +139,8 @@ bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp = NULL);
 bool InitBlockIndex();
 /** Load the block tree and coins database from disk */
 bool LoadBlockIndex();
+/** Unload database information */
+void UnloadBlockIndex();
 /** Verify consistency of the block and coin databases */
 bool VerifyDB();
 /** Print the loaded block tree */

src/noui.cpp

@@ -9,7 +9,7 @@
 
 #include <string>
 
-static int noui_ThreadSafeMessageBox(const std::string& message, const std::string& caption, unsigned int style)
+static bool noui_ThreadSafeMessageBox(const std::string& message, const std::string& caption, unsigned int style)
 {
     std::string strCaption;
     // Check for usage of predefined caption
@@ -29,7 +29,7 @@ static int noui_ThreadSafeMessageBox(const std::string& message, const std::stri
 
     printf("%s: %s\n", strCaption.c_str(), message.c_str());
     fprintf(stderr, "%s: %s\n", strCaption.c_str(), message.c_str());
-    return 4;
+    return false;
 }
 
 static bool noui_ThreadSafeAskFee(int64 /*nFeeRequired*/)

src/qt/bitcoin.cpp

@@ -34,23 +34,27 @@ Q_IMPORT_PLUGIN(qtaccessiblewidgets)
 static BitcoinGUI *guiref;
 static QSplashScreen *splashref;
 
-static void ThreadSafeMessageBox(const std::string& message, const std::string& caption, unsigned int style)
+static bool ThreadSafeMessageBox(const std::string& message, const std::string& caption, unsigned int style)
 {
     // Message from network thread
     if(guiref)
     {
         bool modal = (style & CClientUIInterface::MODAL);
+        bool ret = false;
         // In case of modal message, use blocking connection to wait for user to click a button
         QMetaObject::invokeMethod(guiref, "message",
                                    modal ? GUIUtil::blockingGUIThreadConnection() : Qt::QueuedConnection,
                                    Q_ARG(QString, QString::fromStdString(caption)),
                                    Q_ARG(QString, QString::fromStdString(message)),
-                                   Q_ARG(unsigned int, style));
+                                   Q_ARG(unsigned int, style),
+                                   Q_ARG(bool*, &ret));
+        return ret;
     }
     else
     {
         printf("%s: %s\n", caption.c_str(), message.c_str());
         fprintf(stderr, "%s: %s\n", caption.c_str(), message.c_str());
+        return false;
     }
 }
 

src/qt/bitcoingui.cpp

@@ -606,7 +606,7 @@ void BitcoinGUI::setNumBlocks(int count, int nTotalBlocks)
     progressBar->setToolTip(tooltip);
 }
 
-void BitcoinGUI::message(const QString &title, const QString &message, unsigned int style)
+void BitcoinGUI::message(const QString &title, const QString &message, unsigned int style, bool *ret)
 {
     QString strTitle = tr("Bitcoin") + " - ";
     // Default to information icon
@@ -646,7 +646,9 @@ void BitcoinGUI::message(const QString &title, const QString &message, unsigned
             buttons = QMessageBox::Ok;
 
         QMessageBox mBox((QMessageBox::Icon)nMBoxIcon, strTitle, message, buttons);
-        mBox.exec();
+        int r = mBox.exec();
+        if (ret != NULL)
+            *ret = r == QMessageBox::Ok;
     }
     else
         notificator->notify((Notificator::Class)nNotifyIcon, strTitle, message);

src/qt/bitcoingui.h

@@ -126,8 +126,9 @@ public slots:
        @param[in] message   the displayed text
        @param[in] style     modality and style definitions (icon and used buttons - buttons only for message boxes)
                             @see CClientUIInterface::MessageBoxFlags
+       @param[in] ret       pointer to a bool that will be modified to whether Ok was clicked (modal only)
     */
-    void message(const QString &title, const QString &message, unsigned int style);
+    void message(const QString &title, const QString &message, unsigned int style, bool *ret = NULL);
     /** Asks the user whether to pay the transaction fee or to cancel the transaction.
        It is currently not possible to pass a return value to another thread through
        BlockingQueuedConnection, so an indirected pointer is used.

src/ui_interface.h

@@ -68,7 +68,7 @@ public:
     };
 
     /** Show message box. */
-    boost::signals2::signal<void (const std::string& message, const std::string& caption, unsigned int style)> ThreadSafeMessageBox;
+    boost::signals2::signal<bool (const std::string& message, const std::string& caption, unsigned int style), boost::signals2::last_value<bool> > ThreadSafeMessageBox;
 
     /** Ask the user whether they want to pay a fee or not. */
     boost::signals2::signal<bool (int64 nFeeRequired), boost::signals2::last_value<bool> > ThreadSafeAskFee;