This should fix the racecondition issues with the sqlite backend.
[quassel.git] / src / core / sqlitestorage.cpp
index 1548085..ad610a0 100644 (file)
@@ -1,5 +1,5 @@
 /***************************************************************************
- *   Copyright (C) 2005-07 by the Quassel IRC Team                         *
+ *   Copyright (C) 2005-07 by the Quassel Project                          *
  *   devel@quassel-irc.org                                                 *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
 
 #include <QtSql>
 
+#include "logger.h"
 #include "network.h"
+#include "quassel.h"
+
+int SqliteStorage::_maxRetryCount = 150;
 
 SqliteStorage::SqliteStorage(QObject *parent)
   : AbstractSqlStorage(parent)
@@ -48,6 +52,8 @@ QString SqliteStorage::description() const {
 }
 
 int SqliteStorage::installedSchemaVersion() {
+  // only used when there is a singlethread (during startup)
+  // so we don't need locking here
   QSqlQuery query = logDb().exec("SELECT value FROM coreinfo WHERE key = 'schemaversion'");
   if(query.first())
     return query.value(0).toInt();
@@ -60,708 +66,1714 @@ int SqliteStorage::installedSchemaVersion() {
   return AbstractSqlStorage::installedSchemaVersion();
 }
 
-UserId SqliteStorage::addUser(const QString &user, const QString &password) {
+bool SqliteStorage::updateSchemaVersion(int newVersion) {
+  // only used when there is a singlethread (during startup)
+  // so we don't need locking here
   QSqlQuery query(logDb());
-  query.prepare(queryString("insert_quasseluser"));
-  query.bindValue(":username", user);
-  query.bindValue(":password", cryptedPassword(password));
+  query.prepare("UPDATE coreinfo SET value = :version WHERE key = 'schemaversion'");
+  query.bindValue(":version", newVersion);
   query.exec();
-  if(query.lastError().isValid() && query.lastError().number() == 19) { // user already exists - sadly 19 seems to be the general constraint violation error...
-    return 0;
+
+  bool success = true;
+  if(query.lastError().isValid()) {
+    qCritical() << "SqliteStorage::updateSchemaVersion(int): Updating schema version failed!";
+    success = false;
   }
+  return success;
+}
 
-  query.prepare(queryString("select_userid"));
-  query.bindValue(":username", user);
+bool SqliteStorage::setupSchemaVersion(int version) {
+  // only used when there is a singlethread (during startup)
+  // so we don't need locking here
+  QSqlQuery query(logDb());
+  query.prepare("INSERT INTO coreinfo (key, value) VALUES ('schemaversion', :version)");
+  query.bindValue(":version", version);
   query.exec();
-  query.first();
-  UserId uid = query.value(0).toInt();
-  emit userAdded(uid, user);
+
+  bool success = true;
+  if(query.lastError().isValid()) {
+    qCritical() << "SqliteStorage::setupSchemaVersion(int): Updating schema version failed!";
+    success = false;
+  }
+  return success;
+}
+
+UserId SqliteStorage::addUser(const QString &user, const QString &password) {
+  QSqlDatabase db = logDb();
+  UserId uid;
+
+  db.transaction();
+  // this scope ensures that the query is freed in sqlite before we call unlock()
+  // this ensures that our thread doesn't hold a internal after unlock is called
+  // (see sqlites doc on implicit locking for details)
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("insert_quasseluser"));
+    query.bindValue(":username", user);
+    query.bindValue(":password", cryptedPassword(password));
+    lockForWrite();
+    safeExec(query);
+    if(query.lastError().isValid() && query.lastError().number() == 19) { // user already exists - sadly 19 seems to be the general constraint violation error...
+      db.rollback();
+    } else {
+      uid = query.lastInsertId().toInt();
+      db.commit();
+    }
+  }
+  unlock();
+
+  if(uid.isValid())
+    emit userAdded(uid, user);
   return uid;
 }
 
-void SqliteStorage::updateUser(UserId user, const QString &password) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("update_userpassword"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":password", cryptedPassword(password));
-  query.exec();
+bool SqliteStorage::updateUser(UserId user, const QString &password) {
+  QSqlDatabase db = logDb();
+  bool success = false;
+
+  db.transaction();
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_userpassword"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":password", cryptedPassword(password));
+    lockForWrite();
+    safeExec(query);
+    success = query.numRowsAffected() != 0;
+    db.commit();
+  }
+  unlock();
+  return success;
 }
 
 void SqliteStorage::renameUser(UserId user, const QString &newName) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("update_username"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":username", newName);
-  query.exec();
+  QSqlDatabase db = logDb();
+  db.transaction();
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_username"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":username", newName);
+    lockForWrite();
+    safeExec(query);
+    db.commit();
+  }
+  unlock();
   emit userRenamed(user, newName);
 }
 
 UserId SqliteStorage::validateUser(const QString &user, const QString &password) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_authuser"));
-  query.bindValue(":username", user);
-  query.bindValue(":password", cryptedPassword(password));
-  query.exec();
+  UserId userId;
 
-  if(query.first()) {
-    return query.value(0).toInt();
-  } else {
-    return 0;
+  {
+    QSqlQuery query(logDb());
+    query.prepare(queryString("select_authuser"));
+    query.bindValue(":username", user);
+    query.bindValue(":password", cryptedPassword(password));
+
+    lockForRead();
+    safeExec(query);
+
+    if(query.first()) {
+      userId = query.value(0).toInt();
+    }
   }
+  unlock();
+
+  return userId;
+}
+
+UserId SqliteStorage::getUserId(const QString &username) {
+  UserId userId;
+
+  {
+    QSqlQuery query(logDb());
+    query.prepare(queryString("select_userid"));
+    query.bindValue(":username", username);
+
+    lockForRead();
+    safeExec(query);
+
+    if(query.first()) {
+      userId = query.value(0).toInt();
+    }
+  }
+  unlock();
+
+  return userId;
+}
+
+UserId SqliteStorage::internalUser() {
+  UserId userId;
+
+  {
+    QSqlQuery query(logDb());
+    query.prepare(queryString("select_internaluser"));
+    lockForRead();
+    safeExec(query);
+
+    if(query.first()) {
+      userId = query.value(0).toInt();
+    }
+  }
+  unlock();
+
+  return userId;
 }
 
 void SqliteStorage::delUser(UserId user) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("delete_backlog_by_uid"));
-  query.bindValue(":userid", user.toInt());
-  query.exec();
-  
-  query.prepare(queryString("delete_buffers_by_uid"));
-  query.bindValue(":userid", user.toInt());
-  query.exec();
-  
-  query.prepare(queryString("delete_networks_by_uid"));
-  query.bindValue(":userid", user.toInt());
-  query.exec();
-  
-  query.prepare(queryString("delete_quasseluser"));
-  query.bindValue(":userid", user.toInt());
-  query.exec();
-  // I hate the lack of foreign keys and on delete cascade... :(
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  lockForWrite();
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("delete_backlog_by_uid"));
+    query.bindValue(":userid", user.toInt());
+    safeExec(query);
+
+    query.prepare(queryString("delete_buffers_by_uid"));
+    query.bindValue(":userid", user.toInt());
+    safeExec(query);
+
+    query.prepare(queryString("delete_networks_by_uid"));
+    query.bindValue(":userid", user.toInt());
+    safeExec(query);
+
+    query.prepare(queryString("delete_quasseluser"));
+    query.bindValue(":userid", user.toInt());
+    safeExec(query);
+    // I hate the lack of foreign keys and on delete cascade... :(
+    db.commit();
+  }
+  unlock();
+
   emit userRemoved(user);
 }
 
+void SqliteStorage::setUserSetting(UserId userId, const QString &settingName, const QVariant &data) {
+  QByteArray rawData;
+  QDataStream out(&rawData, QIODevice::WriteOnly);
+  out.setVersion(QDataStream::Qt_4_2);
+  out << data;
+
+  QSqlDatabase db = logDb();
+  db.transaction();
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("insert_user_setting"));
+    query.bindValue(":userid", userId.toInt());
+    query.bindValue(":settingname", settingName);
+    query.bindValue(":settingvalue", rawData);
+    lockForWrite();
+    safeExec(query);
+
+    if(query.lastError().isValid()) {
+      QSqlQuery updateQuery(db);
+      updateQuery.prepare(queryString("update_user_setting"));
+      updateQuery.bindValue(":userid", userId.toInt());
+      updateQuery.bindValue(":settingname", settingName);
+      updateQuery.bindValue(":settingvalue", rawData);
+      safeExec(updateQuery);
+    }
+    db.commit();
+  }
+  unlock();
+}
+
+QVariant SqliteStorage::getUserSetting(UserId userId, const QString &settingName, const QVariant &defaultData) {
+  QVariant data = defaultData;
+  {
+    QSqlQuery query(logDb());
+    query.prepare(queryString("select_user_setting"));
+    query.bindValue(":userid", userId.toInt());
+    query.bindValue(":settingname", settingName);
+    lockForRead();
+    safeExec(query);
+
+    if(query.first()) {
+      QByteArray rawData = query.value(0).toByteArray();
+      QDataStream in(&rawData, QIODevice::ReadOnly);
+      in.setVersion(QDataStream::Qt_4_2);
+      in >> data;
+    }
+  }
+  unlock();
+  return data;
+}
+
+IdentityId SqliteStorage::createIdentity(UserId user, CoreIdentity &identity) {
+  IdentityId identityId;
+
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("insert_identity"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":identityname", identity.identityName());
+    query.bindValue(":realname", identity.realName());
+    query.bindValue(":awaynick", identity.awayNick());
+    query.bindValue(":awaynickenabled", identity.awayNickEnabled() ? 1 : 0);
+    query.bindValue(":awayreason", identity.awayReason());
+    query.bindValue(":awayreasonenabled", identity.awayReasonEnabled() ? 1 : 0);
+    query.bindValue(":autoawayenabled", identity.awayReasonEnabled() ? 1 : 0);
+    query.bindValue(":autoawaytime", identity.autoAwayTime());
+    query.bindValue(":autoawayreason", identity.autoAwayReason());
+    query.bindValue(":autoawayreasonenabled", identity.autoAwayReasonEnabled() ? 1 : 0);
+    query.bindValue(":detachawayenabled", identity.detachAwayEnabled() ? 1 : 0);
+    query.bindValue(":detachawayreason", identity.detachAwayReason());
+    query.bindValue(":detachawayreasonenabled", identity.detachAwayReasonEnabled() ? 1 : 0);
+    query.bindValue(":ident", identity.ident());
+    query.bindValue(":kickreason", identity.kickReason());
+    query.bindValue(":partreason", identity.partReason());
+    query.bindValue(":quitreason", identity.quitReason());
+#ifdef HAVE_SSL
+    query.bindValue(":sslcert", identity.sslCert().toPem());
+    query.bindValue(":sslkey", identity.sslKey().toPem());
+#else
+    query.bindValue(":sslcert", QByteArray());
+    query.bindValue(":sslkey", QByteArray());
+#endif
+
+    lockForWrite();
+    safeExec(query);
+
+    identityId = query.lastInsertId().toInt();
+    if(!identityId.isValid()) {
+      watchQuery(query);
+    } else {
+      QSqlQuery deleteNickQuery(db);
+      deleteNickQuery.prepare(queryString("delete_nicks"));
+      deleteNickQuery.bindValue(":identityid", identityId.toInt());
+      safeExec(deleteNickQuery);
+
+      QSqlQuery insertNickQuery(db);
+      insertNickQuery.prepare(queryString("insert_nick"));
+      foreach(QString nick, identity.nicks()) {
+        insertNickQuery.bindValue(":identityid", identityId.toInt());
+        insertNickQuery.bindValue(":nick", nick);
+        safeExec(insertNickQuery);
+      }
+    }
+    db.commit();
+  }
+  unlock();
+  identity.setId(identityId);
+  return identityId;
+}
+
+bool SqliteStorage::updateIdentity(UserId user, const CoreIdentity &identity) {
+  QSqlDatabase db = logDb();
+  bool error = false;
+  db.transaction();
+
+  {
+    QSqlQuery checkQuery(db);
+    checkQuery.prepare(queryString("select_checkidentity"));
+    checkQuery.bindValue(":identityid", identity.id().toInt());
+    checkQuery.bindValue(":userid", user.toInt());
+    lockForRead();
+    safeExec(checkQuery);
+
+    // there should be exactly one identity for the given id and user
+    error = (!checkQuery.first() || checkQuery.value(0).toInt() != 1);
+  }
+  if(error) {
+    unlock();
+    return false;
+  }
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_identity"));
+    query.bindValue(":identityname", identity.identityName());
+    query.bindValue(":realname", identity.realName());
+    query.bindValue(":awaynick", identity.awayNick());
+    query.bindValue(":awaynickenabled", identity.awayNickEnabled() ? 1 : 0);
+    query.bindValue(":awayreason", identity.awayReason());
+    query.bindValue(":awayreasonenabled", identity.awayReasonEnabled() ? 1 : 0);
+    query.bindValue(":autoawayenabled", identity.awayReasonEnabled() ? 1 : 0);
+    query.bindValue(":autoawaytime", identity.autoAwayTime());
+    query.bindValue(":autoawayreason", identity.autoAwayReason());
+    query.bindValue(":autoawayreasonenabled", identity.autoAwayReasonEnabled() ? 1 : 0);
+    query.bindValue(":detachawayenabled", identity.detachAwayEnabled() ? 1 : 0);
+    query.bindValue(":detachawayreason", identity.detachAwayReason());
+    query.bindValue(":detachawayreasonenabled", identity.detachAwayReasonEnabled() ? 1 : 0);
+    query.bindValue(":ident", identity.ident());
+    query.bindValue(":kickreason", identity.kickReason());
+    query.bindValue(":partreason", identity.partReason());
+    query.bindValue(":quitreason", identity.quitReason());
+#ifdef HAVE_SSL
+    query.bindValue(":sslcert", identity.sslCert().toPem());
+    query.bindValue(":sslkey", identity.sslKey().toPem());
+#else
+    query.bindValue(":sslcert", QByteArray());
+    query.bindValue(":sslkey", QByteArray());
+#endif
+    query.bindValue(":identityid", identity.id().toInt());
+    safeExec(query);
+    watchQuery(query);
+
+    QSqlQuery deleteNickQuery(db);
+    deleteNickQuery.prepare(queryString("delete_nicks"));
+    deleteNickQuery.bindValue(":identityid", identity.id().toInt());
+    safeExec(deleteNickQuery);
+    watchQuery(deleteNickQuery);
+
+    QSqlQuery insertNickQuery(db);
+    insertNickQuery.prepare(queryString("insert_nick"));
+    foreach(QString nick, identity.nicks()) {
+      insertNickQuery.bindValue(":identityid", identity.id().toInt());
+      insertNickQuery.bindValue(":nick", nick);
+      safeExec(insertNickQuery);
+      watchQuery(insertNickQuery);
+    }
+    db.commit();
+  }
+  unlock();
+  return true;
+}
+
+void SqliteStorage::removeIdentity(UserId user, IdentityId identityId) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery checkQuery(db);
+    checkQuery.prepare(queryString("select_checkidentity"));
+    checkQuery.bindValue(":identityid", identityId.toInt());
+    checkQuery.bindValue(":userid", user.toInt());
+    lockForRead();
+    safeExec(checkQuery);
+
+    // there should be exactly one identity for the given id and user
+    error = (!checkQuery.first() || checkQuery.value(0).toInt() != 1);
+  }
+  if(error) {
+    unlock();
+    return;
+  }
+
+  {
+    QSqlQuery deleteNickQuery(db);
+    deleteNickQuery.prepare(queryString("delete_nicks"));
+    deleteNickQuery.bindValue(":identityid", identityId.toInt());
+    safeExec(deleteNickQuery);
+
+    QSqlQuery deleteIdentityQuery(db);
+    deleteIdentityQuery.prepare(queryString("delete_identity"));
+    deleteIdentityQuery.bindValue(":identityid", identityId.toInt());
+    deleteIdentityQuery.bindValue(":userid", user.toInt());
+    safeExec(deleteIdentityQuery);
+    db.commit();
+  }
+  unlock();
+}
+
+QList<CoreIdentity> SqliteStorage::identities(UserId user) {
+  QList<CoreIdentity> identities;
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_identities"));
+    query.bindValue(":userid", user.toInt());
+
+    QSqlQuery nickQuery(db);
+    nickQuery.prepare(queryString("select_nicks"));
+
+    lockForRead();
+    safeExec(query);
+
+    while(query.next()) {
+      CoreIdentity identity(IdentityId(query.value(0).toInt()));
+
+      identity.setIdentityName(query.value(1).toString());
+      identity.setRealName(query.value(2).toString());
+      identity.setAwayNick(query.value(3).toString());
+      identity.setAwayNickEnabled(!!query.value(4).toInt());
+      identity.setAwayReason(query.value(5).toString());
+      identity.setAwayReasonEnabled(!!query.value(6).toInt());
+      identity.setAutoAwayEnabled(!!query.value(7).toInt());
+      identity.setAutoAwayTime(query.value(8).toInt());
+      identity.setAutoAwayReason(query.value(9).toString());
+      identity.setAutoAwayReasonEnabled(!!query.value(10).toInt());
+      identity.setDetachAwayEnabled(!!query.value(11).toInt());
+      identity.setDetachAwayReason(query.value(12).toString());
+      identity.setDetachAwayReasonEnabled(!!query.value(13).toInt());
+      identity.setIdent(query.value(14).toString());
+      identity.setKickReason(query.value(15).toString());
+      identity.setPartReason(query.value(16).toString());
+      identity.setQuitReason(query.value(17).toString());
+#ifdef HAVE_SSL
+      identity.setSslCert(query.value(18).toByteArray());
+      identity.setSslKey(query.value(19).toByteArray());
+#endif
+
+      nickQuery.bindValue(":identityid", identity.id().toInt());
+      QList<QString> nicks;
+      safeExec(nickQuery);
+      watchQuery(nickQuery);
+      while(nickQuery.next()) {
+        nicks << nickQuery.value(0).toString();
+      }
+      identity.setNicks(nicks);
+      identities << identity;
+    }
+    db.commit();
+  }
+  unlock();
+  return identities;
+}
+
 NetworkId SqliteStorage::createNetwork(UserId user, const NetworkInfo &info) {
   NetworkId networkId;
-  QSqlQuery query(logDb());
-  query.prepare(queryString("insert_network"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkname", info.networkName);
-  query.exec();
-  
-  networkId = getNetworkId(user, info.networkName);
-  if(!networkId.isValid()) {
-    watchQuery(&query);
-  } else {
-    updateNetwork(user, info);
+
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("insert_network"));
+    query.bindValue(":userid", user.toInt());
+    bindNetworkInfo(query, info);
+    lockForWrite();
+    safeExec(query);
+    if(!watchQuery(query)) {
+      db.rollback();
+      error = true;
+    } else {
+      networkId = query.lastInsertId().toInt();
+    }
+  }
+  if(error) {
+    unlock();
+    return NetworkId();
+  }
+
+  {
+    QSqlQuery insertServersQuery(db);
+    insertServersQuery.prepare(queryString("insert_server"));
+    foreach(Network::Server server, info.serverList) {
+      insertServersQuery.bindValue(":userid", user.toInt());
+      insertServersQuery.bindValue(":networkid", networkId.toInt());
+      bindServerInfo(insertServersQuery, server);
+      safeExec(insertServersQuery);
+      if(!watchQuery(insertServersQuery)) {
+        db.rollback();
+        error = true;
+        break;
+      }
+    }
+    if(!error)
+      db.commit();
   }
-  return networkId;
+  unlock();
+  if(error)
+    return NetworkId();
+  else
+    return networkId;
+}
+
+void SqliteStorage::bindNetworkInfo(QSqlQuery &query, const NetworkInfo &info) {
+  query.bindValue(":networkname", info.networkName);
+  query.bindValue(":identityid", info.identity.toInt());
+  query.bindValue(":encodingcodec", QString(info.codecForEncoding));
+  query.bindValue(":decodingcodec", QString(info.codecForDecoding));
+  query.bindValue(":servercodec", QString(info.codecForServer));
+  query.bindValue(":userandomserver", info.useRandomServer ? 1 : 0);
+  query.bindValue(":perform", info.perform.join("\n"));
+  query.bindValue(":useautoidentify", info.useAutoIdentify ? 1 : 0);
+  query.bindValue(":autoidentifyservice", info.autoIdentifyService);
+  query.bindValue(":autoidentifypassword", info.autoIdentifyPassword);
+  query.bindValue(":useautoreconnect", info.useAutoReconnect ? 1 : 0);
+  query.bindValue(":autoreconnectinterval", info.autoReconnectInterval);
+  query.bindValue(":autoreconnectretries", info.autoReconnectRetries);
+  query.bindValue(":unlimitedconnectretries", info.unlimitedReconnectRetries ? 1 : 0);
+  query.bindValue(":rejoinchannels", info.rejoinChannels ? 1 : 0);
+  if(info.networkId.isValid())
+    query.bindValue(":networkid", info.networkId.toInt());
+}
+
+void SqliteStorage::bindServerInfo(QSqlQuery &query, const Network::Server &server) {
+  query.bindValue(":hostname", server.host);
+  query.bindValue(":port", server.port);
+  query.bindValue(":password", server.password);
+  query.bindValue(":ssl", server.useSsl ? 1 : 0);
+  query.bindValue(":sslversion", server.sslVersion);
+  query.bindValue(":useproxy", server.useProxy ? 1 : 0);
+  query.bindValue(":proxytype", server.proxyType);
+  query.bindValue(":proxyhost", server.proxyHost);
+  query.bindValue(":proxyport", server.proxyPort);
+  query.bindValue(":proxyuser", server.proxyUser);
+  query.bindValue(":proxypass", server.proxyPass);
 }
 
 bool SqliteStorage::updateNetwork(UserId user, const NetworkInfo &info) {
-  if(!isValidNetwork(user, info.networkId))
-     return false;
-  
-  QSqlQuery updateQuery(logDb());
-  updateQuery.prepare(queryString("update_network"));
-  updateQuery.bindValue(":networkname", info.networkName);
-  updateQuery.bindValue(":identityid", info.identity.toInt());
-  updateQuery.bindValue(":usecustomencoding", info.useCustomEncodings ? 1 : 0);
-  updateQuery.bindValue(":encodingcodec", QString(info.codecForEncoding));
-  updateQuery.bindValue(":decodingcodec", QString(info.codecForDecoding));
-  updateQuery.bindValue(":servercodec", QString(info.codecForServer));
-  updateQuery.bindValue(":userandomserver", info.useRandomServer ? 1 : 0);
-  updateQuery.bindValue(":perform", info.perform.join("\n"));
-  updateQuery.bindValue(":useautoidentify", info.useAutoIdentify ? 1 : 0);
-  updateQuery.bindValue(":autoidentifyservice", info.autoIdentifyService);
-  updateQuery.bindValue(":autoidentifypassword", info.autoIdentifyPassword);
-  updateQuery.bindValue(":useautoreconnect", info.useAutoReconnect ? 1 : 0);
-  updateQuery.bindValue(":autoreconnectinterval", info.autoReconnectInterval);
-  updateQuery.bindValue(":autoreconnectretries", info.autoReconnectRetries);
-  updateQuery.bindValue(":unlimitedconnectretries", info.unlimitedReconnectRetries ? 1 : 0);
-  updateQuery.bindValue(":rejoinchannels", info.rejoinChannels ? 1 : 0);
-  updateQuery.bindValue(":networkid", info.networkId.toInt());
-  updateQuery.exec();
-  if(!watchQuery(&updateQuery))
+  QSqlDatabase db = logDb();
+  bool error = false;
+  db.transaction();
+
+  {
+    QSqlQuery updateQuery(db);
+    updateQuery.prepare(queryString("update_network"));
+    updateQuery.bindValue(":userid", user.toInt());
+    bindNetworkInfo(updateQuery, info);
+
+    lockForWrite();
+    safeExec(updateQuery);
+    if(!watchQuery(updateQuery) || updateQuery.numRowsAffected() != 1) {
+      error = true;
+      db.rollback();
+    }
+  }
+  if(error) {
+    unlock();
     return false;
+  }
 
-  QSqlQuery dropServersQuery(logDb());
-  dropServersQuery.prepare("DELETE FROM ircserver WHERE networkid = :networkid");
-  dropServersQuery.bindValue(":networkid", info.networkId.toInt());
-  dropServersQuery.exec();
-  if(!watchQuery(&dropServersQuery))
+  {
+    QSqlQuery dropServersQuery(db);
+    dropServersQuery.prepare("DELETE FROM ircserver WHERE networkid = :networkid");
+    dropServersQuery.bindValue(":networkid", info.networkId.toInt());
+    safeExec(dropServersQuery);
+    if(!watchQuery(dropServersQuery)) {
+      error = true;
+      db.rollback();
+    }
+  }
+  if(error) {
+    unlock();
     return false;
+  }
 
-  QSqlQuery insertServersQuery(logDb());
-  insertServersQuery.prepare(queryString("insert_server"));
-  foreach(QVariant server_, info.serverList) {
-    QVariantMap server = server_.toMap();
-    insertServersQuery.bindValue(":hostname", server["Host"]);
-    insertServersQuery.bindValue(":port", server["Port"].toInt());
-    insertServersQuery.bindValue(":password", server["Password"]);
-    insertServersQuery.bindValue(":ssl", server["UseSSL"].toBool() ? 1 : 0);
-    insertServersQuery.bindValue(":userid", user.toInt());
-    insertServersQuery.bindValue(":networkid", info.networkId.toInt());
-
-    insertServersQuery.exec();
-    if(!watchQuery(&insertServersQuery))
-      return false;
+  {
+    QSqlQuery insertServersQuery(db);
+    insertServersQuery.prepare(queryString("insert_server"));
+    foreach(Network::Server server, info.serverList) {
+      insertServersQuery.bindValue(":userid", user.toInt());
+      insertServersQuery.bindValue(":networkid", info.networkId.toInt());
+      bindServerInfo(insertServersQuery, server);
+      safeExec(insertServersQuery);
+      if(!watchQuery(insertServersQuery)) {
+        error = true;
+        db.rollback();
+        break;
+      }
+    }
   }
-  
-  return true;
+
+  db.commit();
+  unlock();
+  return !error;
 }
 
 bool SqliteStorage::removeNetwork(UserId user, const NetworkId &networkId) {
-  if(!isValidNetwork(user, networkId))
-     return false;
-
-  bool withTransaction = logDb().driver()->hasFeature(QSqlDriver::Transactions);
-  if(withTransaction) {
-    sync();
-    if(!logDb().transaction()) {
-      qWarning() << "SqliteStorage::removeNetwork(): cannot start transaction. continuing with out rollback support!";
-      withTransaction = false;
-    }
-  }
-  
-  QSqlQuery deleteBacklogQuery(logDb());
-  deleteBacklogQuery.prepare(queryString("delete_backlog_for_network"));
-  deleteBacklogQuery.bindValue(":networkid", networkId.toInt());
-  deleteBacklogQuery.exec();
-  if(!watchQuery(&deleteBacklogQuery)) {
-    if(withTransaction)
-      logDb().rollback();
+  QSqlDatabase db = logDb();
+  bool error = false;
+  db.transaction();
+
+  {
+    QSqlQuery deleteNetworkQuery(db);
+    deleteNetworkQuery.prepare(queryString("delete_network"));
+    deleteNetworkQuery.bindValue(":networkid", networkId.toInt());
+    deleteNetworkQuery.bindValue(":userid", user.toInt());
+    lockForWrite();
+    safeExec(deleteNetworkQuery);
+    if(!watchQuery(deleteNetworkQuery) || deleteNetworkQuery.numRowsAffected() != 1) {
+      error = true;
+      db.rollback();
+    }
+  }
+  if(error) {
+    unlock();
     return false;
   }
-  
-  QSqlQuery deleteBuffersQuery(logDb());
-  deleteBuffersQuery.prepare(queryString("delete_buffers_for_network"));
-  deleteBuffersQuery.bindValue(":networkid", networkId.toInt());
-  deleteBuffersQuery.exec();
-  if(!watchQuery(&deleteBuffersQuery)) {
-    if(withTransaction)
-      logDb().rollback();
+
+  {
+    QSqlQuery deleteBacklogQuery(db);
+    deleteBacklogQuery.prepare(queryString("delete_backlog_for_network"));
+    deleteBacklogQuery.bindValue(":networkid", networkId.toInt());
+    safeExec(deleteBacklogQuery);
+    if(!watchQuery(deleteBacklogQuery)) {
+      db.rollback();
+      error = true;
+    }
+  }
+  if(error) {
+    unlock();
     return false;
   }
-  
-  QSqlQuery deleteServersQuery(logDb());
-  deleteServersQuery.prepare(queryString("delete_ircservers_for_network"));
-  deleteServersQuery.bindValue(":networkid", networkId.toInt());
-  deleteServersQuery.exec();
-  if(!watchQuery(&deleteServersQuery)) {
-    if(withTransaction)
-      logDb().rollback();
+
+  {
+    QSqlQuery deleteBuffersQuery(db);
+    deleteBuffersQuery.prepare(queryString("delete_buffers_for_network"));
+    deleteBuffersQuery.bindValue(":networkid", networkId.toInt());
+    safeExec(deleteBuffersQuery);
+    if(!watchQuery(deleteBuffersQuery)) {
+      db.rollback();
+      error = true;
+    }
+  }
+  if(error) {
+    unlock();
     return false;
   }
-  
-  QSqlQuery deleteNetworkQuery(logDb());
-  deleteNetworkQuery.prepare(queryString("delete_network"));
-  deleteNetworkQuery.bindValue(":networkid", networkId.toInt());
-  deleteNetworkQuery.exec();
-  if(!watchQuery(&deleteNetworkQuery)) {
-    if(withTransaction)
-      logDb().rollback();
+
+  {
+    QSqlQuery deleteServersQuery(db);
+    deleteServersQuery.prepare(queryString("delete_ircservers_for_network"));
+    deleteServersQuery.bindValue(":networkid", networkId.toInt());
+    safeExec(deleteServersQuery);
+    if(!watchQuery(deleteServersQuery)) {
+      db.rollback();
+      error = true;
+    }
+  }
+  if(error) {
+    unlock();
     return false;
   }
 
-  logDb().commit();
+  db.commit();
+  unlock();
   return true;
 }
 
 QList<NetworkInfo> SqliteStorage::networks(UserId user) {
   QList<NetworkInfo> nets;
 
-  QSqlQuery networksQuery(logDb());
-  networksQuery.prepare(queryString("select_networks_for_user"));
-  networksQuery.bindValue(":userid", user.toInt());
-  
-  QSqlQuery serversQuery(logDb());
-  serversQuery.prepare(queryString("select_servers_for_network"));
-
-  networksQuery.exec();
-  if(!watchQuery(&networksQuery))
-    return nets;
-
-  while(networksQuery.next()) {
-    NetworkInfo net;
-    net.networkId = networksQuery.value(0).toInt();
-    net.networkName = networksQuery.value(1).toString();
-    net.identity = networksQuery.value(2).toInt();
-    net.codecForServer = networksQuery.value(3).toString().toAscii();
-    net.codecForEncoding = networksQuery.value(4).toString().toAscii();
-    net.codecForDecoding = networksQuery.value(5).toString().toAscii();
-    net.useRandomServer = networksQuery.value(6).toInt() == 1 ? true : false;
-    net.perform = networksQuery.value(7).toString().split("\n");
-    net.useAutoIdentify = networksQuery.value(8).toInt() == 1 ? true : false;
-    net.autoIdentifyService = networksQuery.value(9).toString();
-    net.autoIdentifyPassword = networksQuery.value(10).toString();
-    net.useAutoReconnect = networksQuery.value(11).toInt() == 1 ? true : false;
-    net.autoReconnectInterval = networksQuery.value(12).toUInt();
-    net.autoReconnectRetries = networksQuery.value(13).toInt();
-    net.unlimitedReconnectRetries = networksQuery.value(14).toInt() == 1 ? true : false;
-    net.rejoinChannels = networksQuery.value(15).toInt() == 1 ? true : false;
-
-    serversQuery.bindValue(":networkid", net.networkId.toInt());
-    serversQuery.exec();
-    if(!watchQuery(&serversQuery))
-      return nets;
-
-    QVariantList servers;
-    while(serversQuery.next()) {
-      QVariantMap server;
-      server["Host"] = serversQuery.value(0).toString();
-      server["Port"] = serversQuery.value(1).toInt();
-      server["Password"] = serversQuery.value(2).toString();
-      server["UseSSL"] = serversQuery.value(3).toInt() == 1 ? true : false;
-      servers << server;
-    }
-    net.serverList = servers;
-    nets << net;
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery networksQuery(db);
+    networksQuery.prepare(queryString("select_networks_for_user"));
+    networksQuery.bindValue(":userid", user.toInt());
+
+    QSqlQuery serversQuery(db);
+    serversQuery.prepare(queryString("select_servers_for_network"));
+
+    lockForRead();
+    safeExec(networksQuery);
+    if(watchQuery(networksQuery)) {
+      while(networksQuery.next()) {
+        NetworkInfo net;
+        net.networkId = networksQuery.value(0).toInt();
+        net.networkName = networksQuery.value(1).toString();
+        net.identity = networksQuery.value(2).toInt();
+        net.codecForServer = networksQuery.value(3).toString().toAscii();
+        net.codecForEncoding = networksQuery.value(4).toString().toAscii();
+        net.codecForDecoding = networksQuery.value(5).toString().toAscii();
+        net.useRandomServer = networksQuery.value(6).toInt() == 1 ? true : false;
+        net.perform = networksQuery.value(7).toString().split("\n");
+        net.useAutoIdentify = networksQuery.value(8).toInt() == 1 ? true : false;
+        net.autoIdentifyService = networksQuery.value(9).toString();
+        net.autoIdentifyPassword = networksQuery.value(10).toString();
+        net.useAutoReconnect = networksQuery.value(11).toInt() == 1 ? true : false;
+        net.autoReconnectInterval = networksQuery.value(12).toUInt();
+        net.autoReconnectRetries = networksQuery.value(13).toInt();
+        net.unlimitedReconnectRetries = networksQuery.value(14).toInt() == 1 ? true : false;
+        net.rejoinChannels = networksQuery.value(15).toInt() == 1 ? true : false;
+
+        serversQuery.bindValue(":networkid", net.networkId.toInt());
+        safeExec(serversQuery);
+        if(!watchQuery(serversQuery)) {
+          nets.clear();
+          break;
+        } else {
+          Network::ServerList servers;
+          while(serversQuery.next()) {
+            Network::Server server;
+            server.host = serversQuery.value(0).toString();
+            server.port = serversQuery.value(1).toUInt();
+            server.password = serversQuery.value(2).toString();
+            server.useSsl = serversQuery.value(3).toInt() == 1 ? true : false;
+            server.sslVersion = serversQuery.value(4).toInt();
+            server.useProxy = serversQuery.value(5).toInt() == 1 ? true : false;
+            server.proxyType = serversQuery.value(6).toInt();
+            server.proxyHost = serversQuery.value(7).toString();
+            server.proxyPort = serversQuery.value(8).toUInt();
+            server.proxyUser = serversQuery.value(9).toString();
+            server.proxyPass = serversQuery.value(10).toString();
+            servers << server;
+          }
+          net.serverList = servers;
+          nets << net;
+        }
+      }
+    }
   }
+  db.commit();
+  unlock();
   return nets;
 }
 
-bool SqliteStorage::isValidNetwork(UserId user, const NetworkId &networkId) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_networkExists"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkid", networkId.toInt());
-  query.exec();
-
-  watchQuery(&query); // there should not occur any errors
-  if(!query.first())
-    return false;
-  
-  Q_ASSERT(!query.next());
-  return true;
-}
-
-bool SqliteStorage::isValidBuffer(const UserId &user, const BufferId &bufferId) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_bufferExists"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":bufferid", bufferId.toInt());
-  query.exec();
-
-  watchQuery(&query);
-  if(!query.first())
-    return false;
-
-  Q_ASSERT(!query.next());
-  return true;
-}
-
-NetworkId SqliteStorage::getNetworkId(UserId user, const QString &network) {
-  QSqlQuery query(logDb());
-  query.prepare("SELECT networkid FROM network "
-               "WHERE userid = :userid AND networkname = :networkname");
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkname", network);
-  query.exec();
-  
-  if(query.first())
-    return query.value(0).toInt();
-  else
-    return NetworkId();
-}
-
 QList<NetworkId> SqliteStorage::connectedNetworks(UserId user) {
   QList<NetworkId> connectedNets;
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_connected_networks"));
-  query.bindValue(":userid", user.toInt());
-  query.exec();
-  watchQuery(&query);
 
-  while(query.next()) {
-    connectedNets << query.value(0).toInt();
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_connected_networks"));
+    query.bindValue(":userid", user.toInt());
+    lockForRead();
+    safeExec(query);
+    watchQuery(query);
+
+    while(query.next()) {
+      connectedNets << query.value(0).toInt();
+    }
+    db.commit();
   }
-  
+  unlock();
   return connectedNets;
 }
 
 void SqliteStorage::setNetworkConnected(UserId user, const NetworkId &networkId, bool isConnected) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("update_network_connected"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkid", networkId.toInt());
-  query.bindValue(":connected", isConnected ? 1 : 0);
-  query.exec();
-  watchQuery(&query);
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_network_connected"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkid", networkId.toInt());
+    query.bindValue(":connected", isConnected ? 1 : 0);
+
+    lockForWrite();
+    safeExec(query);
+    watchQuery(query);
+    db.commit();
+  }
+  unlock();
 }
 
 QHash<QString, QString> SqliteStorage::persistentChannels(UserId user, const NetworkId &networkId) {
   QHash<QString, QString> persistentChans;
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_persistent_channels"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkid", networkId.toInt());
-  query.exec();
-  watchQuery(&query);
 
-  while(query.next()) {
-    persistentChans[query.value(0).toString()] = query.value(1).toString();
+  QSqlDatabase db = logDb();
+  db.transaction();
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_persistent_channels"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkid", networkId.toInt());
+
+    lockForRead();
+    safeExec(query);
+    watchQuery(query);
+    while(query.next()) {
+      persistentChans[query.value(0).toString()] = query.value(1).toString();
+    }
   }
-  
+  unlock();
   return persistentChans;
 }
 
 void SqliteStorage::setChannelPersistent(UserId user, const NetworkId &networkId, const QString &channel, bool isJoined) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("update_buffer_persistent_channel"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkId", networkId.toInt());
-  query.bindValue(":buffercname", channel.toLower());
-  query.bindValue(":joined", isJoined ? 1 : 0);
-  query.exec();
-  watchQuery(&query);
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_buffer_persistent_channel"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkId", networkId.toInt());
+    query.bindValue(":buffercname", channel.toLower());
+    query.bindValue(":joined", isJoined ? 1 : 0);
+
+    lockForWrite();
+    safeExec(query);
+    watchQuery(query);
+    db.commit();
+  }
+  unlock();
 }
 
 void SqliteStorage::setPersistentChannelKey(UserId user, const NetworkId &networkId, const QString &channel, const QString &key) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("update_buffer_set_channel_key"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":networkId", networkId.toInt());
-  query.bindValue(":buffercname", channel.toLower());
-  query.bindValue(":key", key);
-  query.exec();
-  watchQuery(&query);
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_buffer_set_channel_key"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkId", networkId.toInt());
+    query.bindValue(":buffercname", channel.toLower());
+    query.bindValue(":key", key);
+
+    lockForWrite();
+    safeExec(query);
+    watchQuery(query);
+    db.commit();
+  }
+  unlock();
 }
 
+QString SqliteStorage::awayMessage(UserId user, NetworkId networkId) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  QString awayMsg;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_network_awaymsg"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkid", networkId.toInt());
+
+    lockForRead();
+    safeExec(query);
+    watchQuery(query);
+    if(query.first())
+      awayMsg = query.value(0).toString();
+    db.commit();
+  }
+  unlock();
 
-void SqliteStorage::createBuffer(UserId user, const NetworkId &networkId, BufferInfo::Type type, const QString &buffer) {
-  QSqlQuery *query = cachedQuery("insert_buffer");
-  query->bindValue(":userid", user.toInt());
-  query->bindValue(":networkid", networkId.toInt());
-  query->bindValue(":buffertype", (int)type);
-  query->bindValue(":buffername", buffer);
-  query->bindValue(":buffercname", buffer.toLower());
-  query->exec();
-
-  watchQuery(query);
+  return awayMsg;
 }
 
-BufferInfo SqliteStorage::getBufferInfo(UserId user, const NetworkId &networkId, BufferInfo::Type type, const QString &buffer) {
-  QSqlQuery *query = cachedQuery("select_bufferByName");
-  query->bindValue(":networkid", networkId.toInt());
-  query->bindValue(":userid", user.toInt());
-  query->bindValue(":buffercname", buffer.toLower());
-  query->exec();
+void SqliteStorage::setAwayMessage(UserId user, NetworkId networkId, const QString &awayMsg) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_network_set_awaymsg"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkid", networkId.toInt());
+    query.bindValue(":awaymsg", awayMsg);
+
+    lockForWrite();
+    safeExec(query);
+    watchQuery(query);
+    db.commit();
+  }
+  unlock();
+}
 
-  if(!query->first()) {
-    createBuffer(user, networkId, type, buffer);
-    query->exec();
-    if(!query->first()) {
-      watchQuery(query);
-      qWarning() << "unable to create BufferInfo for:" << user << networkId << buffer;
-      return BufferInfo();
-    }
+QString SqliteStorage::userModes(UserId user, NetworkId networkId) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  QString modes;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_network_usermode"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkid", networkId.toInt());
+
+    lockForRead();
+    safeExec(query);
+    watchQuery(query);
+    if(query.first())
+      modes = query.value(0).toString();
+    db.commit();
   }
+  unlock();
+
+  return modes;
+}
 
-  BufferInfo bufferInfo = BufferInfo(query->value(0).toInt(), networkId, (BufferInfo::Type)query->value(1).toInt(), 0, buffer);
-  if(query->next()) {
-    qWarning() << "SqliteStorage::getBufferInfo(): received more then one Buffer!";
-    qWarning() << "         Query:" << query->lastQuery();
-    qWarning() << "  bound Values:" << query->boundValues();
-    Q_ASSERT(false);
+void SqliteStorage::setUserModes(UserId user, NetworkId networkId, const QString &userModes) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_network_set_usermode"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":networkid", networkId.toInt());
+    query.bindValue(":usermode", userModes);
+
+    lockForWrite();
+    safeExec(query);
+    watchQuery(query);
+    db.commit();
   }
+  unlock();
+}
 
+BufferInfo SqliteStorage::bufferInfo(UserId user, const NetworkId &networkId, BufferInfo::Type type, const QString &buffer, bool create) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  BufferInfo bufferInfo;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_bufferByName"));
+    query.bindValue(":networkid", networkId.toInt());
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":buffercname", buffer.toLower());
+
+    lockForRead();
+    safeExec(query);
+
+    if(query.first()) {
+      bufferInfo = BufferInfo(query.value(0).toInt(), networkId, (BufferInfo::Type)query.value(1).toInt(), 0, buffer);
+      if(query.next()) {
+        qCritical() << "SqliteStorage::getBufferInfo(): received more then one Buffer!";
+        qCritical() << "         Query:" << query.lastQuery();
+        qCritical() << "  bound Values:";
+        QList<QVariant> list = query.boundValues().values();
+        for (int i = 0; i < list.size(); ++i)
+          qCritical() << i << ":" << list.at(i).toString().toAscii().data();
+        Q_ASSERT(false);
+      }
+    } else if(create) {
+      // let's create the buffer
+      QSqlQuery createQuery(db);
+      createQuery.prepare(queryString("insert_buffer"));
+      createQuery.bindValue(":userid", user.toInt());
+      createQuery.bindValue(":networkid", networkId.toInt());
+      createQuery.bindValue(":buffertype", (int)type);
+      createQuery.bindValue(":buffername", buffer);
+      createQuery.bindValue(":buffercname", buffer.toLower());
+
+      unlock();
+      lockForWrite();
+      safeExec(createQuery);
+      watchQuery(createQuery);
+      bufferInfo = BufferInfo(createQuery.lastInsertId().toInt(), networkId, type, 0, buffer);
+    }
+  }
+  db.commit();
+  unlock();
   return bufferInfo;
 }
 
 BufferInfo SqliteStorage::getBufferInfo(UserId user, const BufferId &bufferId) {
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_buffer_by_id"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":bufferid", bufferId.toInt());
-  query.exec();
-  if(!watchQuery(&query))
-    return BufferInfo();
-
-  if(!query.first())
-    return BufferInfo();
-
-  BufferInfo bufferInfo(query.value(0).toInt(), query.value(1).toInt(), (BufferInfo::Type)query.value(2).toInt(), 0, query.value(4).toString());
-  Q_ASSERT(!query.next());
-
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  BufferInfo bufferInfo;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_buffer_by_id"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":bufferid", bufferId.toInt());
+
+    lockForRead();
+    safeExec(query);
+
+    if(watchQuery(query) && query.first()) {
+      bufferInfo = BufferInfo(query.value(0).toInt(), query.value(1).toInt(), (BufferInfo::Type)query.value(2).toInt(), 0, query.value(4).toString());
+      Q_ASSERT(!query.next());
+    }
+    db.commit();
+  }
+  unlock();
   return bufferInfo;
 }
 
-QList<BufferInfo> SqliteStorage::requestBuffers(UserId user, QDateTime since) {
-  uint time = 0;
-  if(since.isValid())
-    time = since.toTime_t();
-  
+QList<BufferInfo> SqliteStorage::requestBuffers(UserId user) {
   QList<BufferInfo> bufferlist;
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_buffers"));
-  query.bindValue(":userid", user.toInt());
-  query.bindValue(":time", time);
-  
-  query.exec();
-  watchQuery(&query);
-  while(query.next()) {
-    bufferlist << BufferInfo(query.value(0).toInt(), query.value(1).toInt(), (BufferInfo::Type)query.value(2).toInt(), query.value(3).toInt(), query.value(4).toString());
+
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_buffers"));
+    query.bindValue(":userid", user.toInt());
+
+    lockForRead();
+    safeExec(query);
+    watchQuery(query);
+    while(query.next()) {
+      bufferlist << BufferInfo(query.value(0).toInt(), query.value(1).toInt(), (BufferInfo::Type)query.value(2).toInt(), query.value(3).toInt(), query.value(4).toString());
+    }
+    db.commit();
   }
+  unlock();
+
   return bufferlist;
 }
 
-bool SqliteStorage::removeBuffer(const UserId &user, const BufferId &bufferId) {
-  if(!isValidBuffer(user, bufferId))
-    return false;
+QList<BufferId> SqliteStorage::requestBufferIdsForNetwork(UserId user, NetworkId networkId) {
+  QList<BufferId> bufferList;
 
-  QSqlQuery delBacklogQuery(logDb());
-  delBacklogQuery.prepare(queryString("delete_backlog_for_buffer"));
-  delBacklogQuery.bindValue(":bufferid", bufferId.toInt());
-  delBacklogQuery.exec();
-  if(!watchQuery(&delBacklogQuery))
-    return false;
+  QSqlDatabase db = logDb();
+  db.transaction();
 
-  QSqlQuery delBufferQuery(logDb());
-  delBufferQuery.prepare(queryString("delete_buffer_for_bufferid"));
-  delBufferQuery.bindValue(":bufferid", bufferId.toInt());
-  delBufferQuery.exec();
-  if(!watchQuery(&delBufferQuery))
-    return false;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_buffers_for_network"));
+    query.bindValue(":networkid", networkId.toInt());
+    query.bindValue(":userid", user.toInt());
 
-  return true;
+    lockForRead();
+    safeExec(query);
+    watchQuery(query);
+    while(query.next()) {
+      bufferList << BufferId(query.value(0).toInt());
+    }
+    db.commit();
+  }
+  unlock();
+
+  return bufferList;
 }
 
-BufferId SqliteStorage::renameBuffer(const UserId &user, const NetworkId &networkId, const QString &newName, const QString &oldName) {
-  // check if such a buffer exists...
-  QSqlQuery existsQuery(logDb());
-  existsQuery.prepare(queryString("select_bufferByName"));
-  existsQuery.bindValue(":networkid", networkId.toInt());
-  existsQuery.bindValue(":userid", user.toInt());
-  existsQuery.bindValue(":buffercname", oldName.toLower());
-  existsQuery.exec();
-  if(!watchQuery(&existsQuery))
-    return false;
+bool SqliteStorage::removeBuffer(const UserId &user, const BufferId &bufferId) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery delBufferQuery(db);
+    delBufferQuery.prepare(queryString("delete_buffer_for_bufferid"));
+    delBufferQuery.bindValue(":bufferid", bufferId.toInt());
+    delBufferQuery.bindValue(":userid", user.toInt());
+
+    lockForWrite();
+    safeExec(delBufferQuery);
+
+    error = (!watchQuery(delBufferQuery) || delBufferQuery.numRowsAffected() != 1);
+  }
 
-  if(!existsQuery.first())
+  if(error) {
+    db.rollback();
+    unlock();
     return false;
+  }
 
-  const int bufferid = existsQuery.value(0).toInt();
+  {
+    QSqlQuery delBacklogQuery(db);
+    delBacklogQuery.prepare(queryString("delete_backlog_for_buffer"));
+    delBacklogQuery.bindValue(":bufferid", bufferId.toInt());
 
-  Q_ASSERT(!existsQuery.next());
+    safeExec(delBacklogQuery);
+    error = !watchQuery(delBacklogQuery);
+  }
 
-  // ... and if the new name is still free.
-  existsQuery.bindValue(":networkid", networkId.toInt());
-  existsQuery.bindValue(":userid", user.toInt());
-  existsQuery.bindValue(":buffercname", newName.toLower());
-  existsQuery.exec();
-  if(!watchQuery(&existsQuery))
+  if(error) {
+    db.rollback();
+  } else {
+    db.commit();
+  }
+  unlock();
+  return !error;
+}
+
+bool SqliteStorage::renameBuffer(const UserId &user, const BufferId &bufferId, const QString &newName) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_buffer_name"));
+    query.bindValue(":buffername", newName);
+    query.bindValue(":buffercname", newName.toLower());
+    query.bindValue(":bufferid", bufferId.toInt());
+    query.bindValue(":userid", user.toInt());
+
+    lockForWrite();
+    safeExec(query);
+
+    error = query.lastError().isValid();
+    // unexepcted error occured (19 == constraint violation)
+    if(error && query.lastError().number() != 19) {
+      watchQuery(query);
+    } else {
+      error |= (query.numRowsAffected() != 1);
+    }
+  }
+  if(error) {
+    db.rollback();
+  } else {
+    db.commit();
+  }
+  unlock();
+  return !error;
+}
+
+bool SqliteStorage::mergeBuffersPermanently(const UserId &user, const BufferId &bufferId1, const BufferId &bufferId2) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery checkQuery(db);
+    checkQuery.prepare(queryString("select_buffers_for_merge"));
+    checkQuery.bindValue(":oldbufferid", bufferId2.toInt());
+    checkQuery.bindValue(":newbufferid", bufferId1.toInt());
+    checkQuery.bindValue(":userid", user.toInt());
+
+    lockForRead();
+    safeExec(checkQuery);
+    error = (!checkQuery.first() || checkQuery.value(0).toInt() != 2);
+  }
+  if(error) {
+    db.rollback();
+    unlock();
     return false;
+  }
 
-  if(existsQuery.first())
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_backlog_bufferid"));
+    query.bindValue(":oldbufferid", bufferId2.toInt());
+    query.bindValue(":newbufferid", bufferId1.toInt());
+    safeExec(query);
+    error = !watchQuery(query);
+  }
+  if(error) {
+    db.rollback();
+    unlock();
     return false;
+  }
 
-  QSqlQuery renameBufferQuery(logDb());
-  renameBufferQuery.prepare(queryString("update_buffer_name"));
-  renameBufferQuery.bindValue(":buffername", newName);
-  renameBufferQuery.bindValue(":buffercname", newName.toLower());
-  renameBufferQuery.bindValue(":bufferid", bufferid);
-  renameBufferQuery.exec();
-  if(watchQuery(&existsQuery))
-    return BufferId(bufferid);
-  else
-    return BufferId();
-}
+  {
+    QSqlQuery delBufferQuery(db);
+    delBufferQuery.prepare(queryString("delete_buffer_for_bufferid"));
+    delBufferQuery.bindValue(":bufferid", bufferId2.toInt());
+    delBufferQuery.bindValue(":userid", user.toInt());
+    safeExec(delBufferQuery);
+    error = !watchQuery(delBufferQuery);
+  }
 
-void SqliteStorage::setBufferLastSeen(UserId user, const BufferId &bufferId, const QDateTime &seenDate) {
-  QSqlQuery *query = cachedQuery("update_buffer_lastseen");
-  query->bindValue(":userid", user.toInt());
-  query->bindValue(":bufferid", bufferId.toInt());
-  query->bindValue(":lastseen", seenDate.toTime_t());
-  query->exec();
-  watchQuery(query);
+  if(error) {
+    db.rollback();
+  } else {
+    db.commit();
+  }
+  unlock();
+  return !error;
 }
 
-QHash<BufferId, QDateTime> SqliteStorage::bufferLastSeenDates(UserId user) {
-  QHash<BufferId, QDateTime> lastSeenHash;
-  QSqlQuery query(logDb());
-  query.prepare(queryString("select_buffer_lastseen_dates"));
-  query.bindValue(":userid", user.toInt());
-  query.exec();
-  if(!watchQuery(&query))
-    return lastSeenHash;
+void SqliteStorage::setBufferLastSeenMsg(UserId user, const BufferId &bufferId, const MsgId &msgId) {
+  QSqlDatabase db = logDb();
+  db.transaction();
 
-  while(query.next()) {
-    lastSeenHash[query.value(0).toInt()] = QDateTime::fromTime_t(query.value(1).toUInt());
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("update_buffer_lastseen"));
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":bufferid", bufferId.toInt());
+    query.bindValue(":lastseenmsgid", msgId.toInt());
+
+    lockForWrite();
+    safeExec(query);
+    watchQuery(query);
   }
-  return lastSeenHash;
+  db.commit();
+  unlock();
 }
 
-MsgId SqliteStorage::logMessage(Message msg) {
-  QSqlQuery *logMessageQuery = cachedQuery("insert_message");
-  logMessageQuery->bindValue(":time", msg.timestamp().toTime_t());
-  logMessageQuery->bindValue(":bufferid", msg.bufferInfo().bufferId().toInt());
-  logMessageQuery->bindValue(":type", msg.type());
-  logMessageQuery->bindValue(":flags", msg.flags());
-  logMessageQuery->bindValue(":sender", msg.sender());
-  logMessageQuery->bindValue(":message", msg.text());
-  logMessageQuery->exec();
-  
-  if(logMessageQuery->lastError().isValid()) {
-    // constraint violation - must be NOT NULL constraint - probably the sender is missing...
-    if(logMessageQuery->lastError().number() == 19) {
-      QSqlQuery *addSenderQuery = cachedQuery("insert_sender");
-      addSenderQuery->bindValue(":sender", msg.sender());
-      addSenderQuery->exec();
-      watchQuery(addSenderQuery);
-      logMessageQuery->exec();
-      if(!watchQuery(logMessageQuery))
-       return 0;
-    } else {
-      watchQuery(logMessageQuery);
+QHash<BufferId, MsgId> SqliteStorage::bufferLastSeenMsgIds(UserId user) {
+  QHash<BufferId, MsgId> lastSeenHash;
+
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery query(db);
+    query.prepare(queryString("select_buffer_lastseen_messages"));
+    query.bindValue(":userid", user.toInt());
+
+    lockForRead();
+    safeExec(query);
+    error = !watchQuery(query);
+    if(!error) {
+      while(query.next()) {
+        lastSeenHash[query.value(0).toInt()] = query.value(1).toInt();
+      }
     }
   }
 
-  MsgId msgId = logMessageQuery->lastInsertId().toInt();
-  Q_ASSERT(msgId.isValid());
-  return msgId;
+  db.commit();
+  unlock();
+  return lastSeenHash;
 }
 
-QList<Message> SqliteStorage::requestMsgs(BufferInfo buffer, int lastmsgs, int offset) {
-  QList<Message> messagelist;
-  // we have to determine the real offset first
-  QSqlQuery *offsetQuery = cachedQuery("select_messagesOffset");
-  offsetQuery->bindValue(":bufferid", buffer.bufferId().toInt());
-  offsetQuery->bindValue(":messageid", offset);
-  offsetQuery->exec();
-  offsetQuery->first();
-  offset = offsetQuery->value(0).toInt();
-
-  // now let's select the messages
-  QSqlQuery *msgQuery = cachedQuery("select_messages");
-  msgQuery->bindValue(":bufferid", buffer.bufferId().toInt());
-  msgQuery->bindValue(":limit", lastmsgs);
-  msgQuery->bindValue(":offset", offset);
-  msgQuery->exec();
-  
-  watchQuery(msgQuery);
-  
-  while(msgQuery->next()) {
-    Message msg(QDateTime::fromTime_t(msgQuery->value(1).toInt()),
-                buffer,
-                (Message::Type)msgQuery->value(2).toUInt(),
-                msgQuery->value(5).toString(),
-                msgQuery->value(4).toString(),
-                msgQuery->value(3).toUInt());
-    msg.setMsgId(msgQuery->value(0).toInt());
-    messagelist << msg;
+bool SqliteStorage::logMessage(Message &msg) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  {
+    QSqlQuery logMessageQuery(db);
+    logMessageQuery.prepare(queryString("insert_message"));
+
+    logMessageQuery.bindValue(":time", msg.timestamp().toTime_t());
+    logMessageQuery.bindValue(":bufferid", msg.bufferInfo().bufferId().toInt());
+    logMessageQuery.bindValue(":type", msg.type());
+    logMessageQuery.bindValue(":flags", (int)msg.flags());
+    logMessageQuery.bindValue(":sender", msg.sender());
+    logMessageQuery.bindValue(":message", msg.contents());
+
+    lockForWrite();
+    safeExec(logMessageQuery);
+
+    if(logMessageQuery.lastError().isValid()) {
+      // constraint violation - must be NOT NULL constraint - probably the sender is missing...
+      if(logMessageQuery.lastError().number() == 19) {
+        QSqlQuery addSenderQuery(db);
+        addSenderQuery.prepare(queryString("insert_sender"));
+        addSenderQuery.bindValue(":sender", msg.sender());
+        safeExec(addSenderQuery);
+        safeExec(logMessageQuery);
+        error = !watchQuery(logMessageQuery);
+      } else {
+        watchQuery(logMessageQuery);
+      }
+    }
+    if(!error) {
+      MsgId msgId = logMessageQuery.lastInsertId().toInt();
+      if(msgId.isValid()) {
+        msg.setMsgId(msgId);
+      } else {
+        error = true;
+      }
+    }
   }
-  return messagelist;
+
+  if(error) {
+    db.rollback();
+  } else {
+    db.commit();
+  }
+
+  unlock();
+  return !error;
 }
 
+bool SqliteStorage::logMessages(MessageList &msgs) {
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  {
+    QSet<QString> senders;
+    QSqlQuery addSenderQuery(db);
+    addSenderQuery.prepare(queryString("insert_sender"));
+    lockForWrite();
+    for(int i = 0; i < msgs.count(); i++) {
+      const QString &sender = msgs.at(i).sender();
+      if(senders.contains(sender))
+        continue;
+      senders << sender;
+
+      addSenderQuery.bindValue(":sender", sender);
+      safeExec(addSenderQuery);
+    }
+  }
 
-QList<Message> SqliteStorage::requestMsgs(BufferInfo buffer, QDateTime since, int offset) {
+  bool error = false;
+  {
+    QSqlQuery logMessageQuery(db);
+    logMessageQuery.prepare(queryString("insert_message"));
+    for(int i = 0; i < msgs.count(); i++) {
+      Message &msg = msgs[i];
+
+      logMessageQuery.bindValue(":time", msg.timestamp().toTime_t());
+      logMessageQuery.bindValue(":bufferid", msg.bufferInfo().bufferId().toInt());
+      logMessageQuery.bindValue(":type", msg.type());
+      logMessageQuery.bindValue(":flags", (int)msg.flags());
+      logMessageQuery.bindValue(":sender", msg.sender());
+      logMessageQuery.bindValue(":message", msg.contents());
+
+      safeExec(logMessageQuery);
+      if(!watchQuery(logMessageQuery)) {
+        error = true;
+        break;
+      } else {
+        msg.setMsgId(logMessageQuery.lastInsertId().toInt());
+      }
+    }
+  }
+
+  if(error) {
+    db.rollback();
+    unlock();
+    // we had a rollback in the db so we need to reset all msgIds
+    for(int i = 0; i < msgs.count(); i++) {
+      msgs[i].setMsgId(MsgId());
+    }
+  } else {
+    db.commit();
+    unlock();
+  }
+  return !error;
+}
+
+QList<Message> SqliteStorage::requestMsgs(UserId user, BufferId bufferId, MsgId first, MsgId last, int limit) {
   QList<Message> messagelist;
-  // we have to determine the real offset first
-  QSqlQuery *offsetQuery = cachedQuery("select_messagesSinceOffset");
-  offsetQuery->bindValue(":bufferid", buffer.bufferId().toInt());
-  offsetQuery->bindValue(":since", since.toTime_t());
-  offsetQuery->exec();
-  offsetQuery->first();
-  offset = offsetQuery->value(0).toInt();
-
-  // now let's select the messages
-  QSqlQuery *msgQuery = cachedQuery("select_messagesSince");
-  msgQuery->bindValue(":bufferid", buffer.bufferId().toInt());
-  msgQuery->bindValue(":since", since.toTime_t());
-  msgQuery->bindValue(":offset", offset);
-  msgQuery->exec();
-
-  watchQuery(msgQuery);
-  
-  while(msgQuery->next()) {
-    Message msg(QDateTime::fromTime_t(msgQuery->value(1).toInt()),
-                buffer,
-                (Message::Type)msgQuery->value(2).toUInt(),
-                msgQuery->value(5).toString(),
-                msgQuery->value(4).toString(),
-                msgQuery->value(3).toUInt());
-    msg.setMsgId(msgQuery->value(0).toInt());
-    messagelist << msg;
+
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  bool error = false;
+  BufferInfo bufferInfo;
+  {
+    // code dupication from getBufferInfo:
+    // this is due to the impossibility of nesting transactions and recursive locking
+    QSqlQuery bufferInfoQuery(db);
+    bufferInfoQuery.prepare(queryString("select_buffer_by_id"));
+    bufferInfoQuery.bindValue(":userid", user.toInt());
+    bufferInfoQuery.bindValue(":bufferid", bufferId.toInt());
+
+    lockForRead();
+    safeExec(bufferInfoQuery);
+    error = !watchQuery(bufferInfoQuery) || !bufferInfoQuery.first();
+    if(!error) {
+      bufferInfo = BufferInfo(bufferInfoQuery.value(0).toInt(), bufferInfoQuery.value(1).toInt(), (BufferInfo::Type)bufferInfoQuery.value(2).toInt(), 0, bufferInfoQuery.value(4).toString());
+      error = !bufferInfo.isValid();
+    }
+  }
+  if(error) {
+    db.rollback();
+    unlock();
+    return messagelist;
+  }
+
+  {
+    QSqlQuery query(db);
+    if(last == -1 && first == -1) {
+      query.prepare(queryString("select_messagesNewestK"));
+    } else if(last == -1) {
+      query.prepare(queryString("select_messagesNewerThan"));
+      query.bindValue(":firstmsg", first.toInt());
+    } else {
+      query.prepare(queryString("select_messages"));
+      query.bindValue(":lastmsg", last.toInt());
+      query.bindValue(":firstmsg", first.toInt());
+    }
+    query.bindValue(":bufferid", bufferId.toInt());
+    query.bindValue(":limit", limit);
+
+    safeExec(query);
+    watchQuery(query);
+
+    while(query.next()) {
+      Message msg(QDateTime::fromTime_t(query.value(1).toInt()),
+                  bufferInfo,
+                  (Message::Type)query.value(2).toUInt(),
+                  query.value(5).toString(),
+                  query.value(4).toString(),
+                  (Message::Flags)query.value(3).toUInt());
+      msg.setMsgId(query.value(0).toInt());
+      messagelist << msg;
+    }
   }
+  db.commit();
+  unlock();
 
   return messagelist;
 }
 
-
-QList<Message> SqliteStorage::requestMsgRange(BufferInfo buffer, int first, int last) {
+QList<Message> SqliteStorage::requestAllMsgs(UserId user, MsgId first, MsgId last, int limit) {
   QList<Message> messagelist;
-  QSqlQuery *rangeQuery = cachedQuery("select_messageRange");
-  rangeQuery->bindValue(":bufferid", buffer.bufferId().toInt());
-  rangeQuery->bindValue(":firstmsg", first);
-  rangeQuery->bindValue(":lastmsg", last);
-  rangeQuery->exec();
-
-  watchQuery(rangeQuery);
-  
-  while(rangeQuery->next()) {
-    Message msg(QDateTime::fromTime_t(rangeQuery->value(1).toInt()),
-                buffer,
-                (Message::Type)rangeQuery->value(2).toUInt(),
-                rangeQuery->value(5).toString(),
-                rangeQuery->value(4).toString(),
-                rangeQuery->value(3).toUInt());
-    msg.setMsgId(rangeQuery->value(0).toInt());
-    messagelist << msg;
-  }
 
+  QSqlDatabase db = logDb();
+  db.transaction();
+
+  QHash<BufferId, BufferInfo> bufferInfoHash;
+  {
+    QSqlQuery bufferInfoQuery(db);
+    bufferInfoQuery.prepare(queryString("select_buffers"));
+    bufferInfoQuery.bindValue(":userid", user.toInt());
+
+    lockForRead();
+    safeExec(bufferInfoQuery);
+    watchQuery(bufferInfoQuery);
+    while(bufferInfoQuery.next()) {
+      BufferInfo bufferInfo = BufferInfo(bufferInfoQuery.value(0).toInt(), bufferInfoQuery.value(1).toInt(), (BufferInfo::Type)bufferInfoQuery.value(2).toInt(), bufferInfoQuery.value(3).toInt(), bufferInfoQuery.value(4).toString());
+      bufferInfoHash[bufferInfo.bufferId()] = bufferInfo;
+    }
+
+    QSqlQuery query(db);
+    if(last == -1) {
+      query.prepare(queryString("select_messagesAllNew"));
+    } else {
+      query.prepare(queryString("select_messagesAll"));
+      query.bindValue(":lastmsg", last.toInt());
+    }
+    query.bindValue(":userid", user.toInt());
+    query.bindValue(":firstmsg", first.toInt());
+    query.bindValue(":limit", limit);
+    safeExec(query);
+
+    watchQuery(query);
+
+    while(query.next()) {
+      Message msg(QDateTime::fromTime_t(query.value(2).toInt()),
+                  bufferInfoHash[query.value(1).toInt()],
+                  (Message::Type)query.value(3).toUInt(),
+                  query.value(6).toString(),
+                  query.value(5).toString(),
+                  (Message::Flags)query.value(4).toUInt());
+      msg.setMsgId(query.value(0).toInt());
+      messagelist << msg;
+    }
+  }
+  db.commit();
+  unlock();
   return messagelist;
 }
 
 QString SqliteStorage::backlogFile() {
-  // kinda ugly, but I currently see no other way to do that
-#ifdef Q_OS_WIN32
-  QString quasselDir = QDir::homePath() + qgetenv("APPDATA") + "\\quassel\\";
-#else
-  QString quasselDir = QDir::homePath() + "/.quassel/";
-#endif
+  return Quassel::configDirPath() + "quassel-storage.sqlite";
+}
+
+bool SqliteStorage::safeExec(QSqlQuery &query, int retryCount) {
+  query.exec();
+
+  if(!query.lastError().isValid())
+    return true;
+
+  switch(query.lastError().number()) {
+  case 5: // SQLITE_BUSY         5   /* The database file is locked */
+  case 6: // SQLITE_LOCKED       6   /* A table in the database is locked */
+    if(retryCount < _maxRetryCount)
+      return safeExec(query, retryCount + 1);
+  default:
+    return false;
+  }
+}
+
+
+// ========================================
+//  SqliteMigration
+// ========================================
+SqliteMigrationReader::SqliteMigrationReader()
+  : SqliteStorage(),
+    _maxId(0)
+{
+}
 
-  QDir qDir(quasselDir);
-  if(!qDir.exists(quasselDir))
-    qDir.mkpath(quasselDir);
-  
-  return quasselDir + "quassel-storage.sqlite";  
+void SqliteMigrationReader::setMaxId(MigrationObject mo) {
+  QString queryString;
+  switch(mo) {
+  case Sender:
+    queryString = "SELECT max(senderid) FROM sender";
+    break;
+  case Backlog:
+    queryString = "SELECT max(messageid) FROM backlog";
+    break;
+  default:
+    _maxId = 0;
+    return;
+  }
+  QSqlQuery query = logDb().exec(queryString);
+  query.first();
+  _maxId = query.value(0).toInt();
 }
 
+bool SqliteMigrationReader::prepareQuery(MigrationObject mo) {
+  setMaxId(mo);
+
+  switch(mo) {
+  case QuasselUser:
+    newQuery(queryString("migrate_read_quasseluser"), logDb());
+    break;
+  case Identity:
+    newQuery(queryString("migrate_read_identity"), logDb());
+    break;
+  case IdentityNick:
+    newQuery(queryString("migrate_read_identity_nick"), logDb());
+    break;
+  case Network:
+    newQuery(queryString("migrate_read_network"), logDb());
+    break;
+  case Buffer:
+    newQuery(queryString("migrate_read_buffer"), logDb());
+    break;
+  case Sender:
+    newQuery(queryString("migrate_read_sender"), logDb());
+    bindValue(0, 0);
+    bindValue(1, stepSize());
+    break;
+  case Backlog:
+    newQuery(queryString("migrate_read_backlog"), logDb());
+    bindValue(0, 0);
+    bindValue(1, stepSize());
+    break;
+  case IrcServer:
+    newQuery(queryString("migrate_read_ircserver"), logDb());
+    break;
+  case UserSetting:
+    newQuery(queryString("migrate_read_usersetting"), logDb());
+    break;
+  }
+  return exec();
+}
 
-// ONLY NEEDED FOR MIGRATION
-bool SqliteStorage::init(const QVariantMap &settings) {
-  if(!AbstractSqlStorage::init(settings))
+bool SqliteMigrationReader::readMo(QuasselUserMO &user) {
+  if(!next())
     return false;
 
-  QSqlQuery checkMigratedQuery(logDb());
-  checkMigratedQuery.prepare("SELECT DISTINCT typeOf(password) FROM quasseluser");
-  checkMigratedQuery.exec();
-  if(!watchQuery(&checkMigratedQuery))
+  user.id = value(0).toInt();
+  user.username = value(1).toString();
+  user.password = value(2).toString();
+  return true;
+}
+
+bool SqliteMigrationReader::readMo(IdentityMO &identity) {
+  if(!next())
     return false;
 
-  if(!checkMigratedQuery.first())
+  identity.id = value(0).toInt();
+  identity.userid = value(1).toInt();
+  identity.identityname = value(2).toString();
+  identity.realname = value(3).toString();
+  identity.awayNick = value(4).toString();
+  identity.awayNickEnabled = value(5).toInt() == 1 ? true : false;
+  identity.awayReason = value(6).toString();
+  identity.awayReasonEnabled = value(7).toInt() == 1 ? true : false;
+  identity.autoAwayEnabled = value(8).toInt() == 1 ? true : false;
+  identity.autoAwayTime = value(9).toInt();
+  identity.autoAwayReason = value(10).toString();
+  identity.autoAwayReasonEnabled = value(11).toInt() == 1 ? true : false;
+  identity.detachAwayEnabled = value(12).toInt() == 1 ? true : false;
+  identity.detachAwayReason = value(13).toString();
+  identity.detchAwayReasonEnabled = value(14).toInt() == 1 ? true : false;
+  identity.ident = value(15).toString();
+  identity.kickReason = value(16).toString();
+  identity.partReason = value(17).toString();
+  identity.quitReason = value(18).toString();
+  identity.sslCert = value(19).toByteArray();
+  identity.sslKey = value(20).toByteArray();
+  return true;
+}
+
+bool SqliteMigrationReader::readMo(IdentityNickMO &identityNick) {
+  if(!next())
     return false;
 
-  QString passType = checkMigratedQuery.value(0).toString().toLower();
-  if(passType == "text")
-    return true; // allready migrated
+  identityNick.nickid = value(0).toInt();
+  identityNick.identityId = value(1).toInt();
+  identityNick.nick = value(2).toString();
+  return true;
+}
 
-  Q_ASSERT(passType == "blob");
-  
-  QSqlQuery getPasswordsQuery(logDb());
-  getPasswordsQuery.prepare("SELECT userid, password FROM quasseluser");
-  getPasswordsQuery.exec();
+bool SqliteMigrationReader::readMo(NetworkMO &network) {
+  if(!next())
+    return false;
+
+  network.networkid = value(0).toInt();
+  network.userid = value(1).toInt();
+  network.networkname = value(2).toString();
+  network.identityid = value(3).toInt();
+  network.encodingcodec = value(4).toString();
+  network.decodingcodec = value(5).toString();
+  network.servercodec = value(6).toString();
+  network.userandomserver = value(7).toInt() == 1 ? true : false;
+  network.perform = value(8).toString();
+  network.useautoidentify = value(9).toInt() == 1 ? true : false;
+  network.autoidentifyservice = value(10).toString();
+  network.autoidentifypassword = value(11).toString();
+  network.useautoreconnect = value(12).toInt() == 1 ? true : false;
+  network.autoreconnectinterval = value(13).toInt();
+  network.autoreconnectretries = value(14).toInt();
+  network.unlimitedconnectretries = value(15).toInt() == 1 ? true : false;
+  network.rejoinchannels = value(16).toInt() == 1 ? true : false;
+  network.connected = value(17).toInt() == 1 ? true : false;
+  network.usermode = value(18).toString();
+  network.awaymessage = value(19).toString();
+  network.attachperform = value(20).toString();
+  network.detachperform = value(21).toString();
+  return true;
+}
 
-  if(!watchQuery(&getPasswordsQuery)) {
-    qWarning() << "unable to migrate to new password format!";
+bool SqliteMigrationReader::readMo(BufferMO &buffer) {
+  if(!next())
     return false;
-  }
 
-  QHash<int, QByteArray> passHash;
-  while(getPasswordsQuery.next()) {
-    passHash[getPasswordsQuery.value(0).toInt()] = getPasswordsQuery.value(1).toByteArray();
+  buffer.bufferid = value(0).toInt();
+  buffer.userid = value(1).toInt();
+  buffer.groupid = value(2).toInt();
+  buffer.networkid = value(3).toInt();
+  buffer.buffername = value(4).toString();
+  buffer.buffercname = value(5).toString();
+  buffer.buffertype = value(6).toInt();
+  buffer.lastseenmsgid = value(7).toInt();
+  buffer.key = value(8).toString();
+  buffer.joined = value(9).toInt() == 1 ? true : false;
+  return true;
+}
+
+bool SqliteMigrationReader::readMo(SenderMO &sender) {
+  int skipSteps = 0;
+  while(!next()) {
+    if(sender.senderId < _maxId) {
+      bindValue(0, sender.senderId + (skipSteps * stepSize()));
+      bindValue(1, sender.senderId + ((skipSteps + 1) * stepSize()));
+      skipSteps++;
+      if(!exec())
+       return false;
+    } else {
+      return false;
+    }
   }
 
-  QSqlQuery setPasswordsQuery(logDb());
-  setPasswordsQuery.prepare("UPDATE quasseluser SET password = :password WHERE userid = :userid");
-  foreach(int userId, passHash.keys()) {
-    setPasswordsQuery.bindValue(":password", QString(passHash[userId]));
-    setPasswordsQuery.bindValue(":userid", userId);
-    setPasswordsQuery.exec();
-    watchQuery(&setPasswordsQuery);
+  sender.senderId = value(0).toInt();
+  sender.sender = value(1).toString();
+  return true;
+}
+
+bool SqliteMigrationReader::readMo(BacklogMO &backlog) {
+  int skipSteps = 0;
+  while(!next()) {
+    if(backlog.messageid < _maxId) {
+      bindValue(0, backlog.messageid.toInt() + (skipSteps * stepSize()));
+      bindValue(1, backlog.messageid.toInt() + ((skipSteps + 1) * stepSize()));
+      skipSteps++;
+      if(!exec())
+       return false;
+    } else {
+      return false;
+    }
   }
 
-  qDebug() << "successfully migrated passwords!";
+  backlog.messageid = value(0).toInt();
+  backlog.time = QDateTime::fromTime_t(value(1).toInt()).toUTC();
+  backlog.bufferid = value(2).toInt();
+  backlog.type = value(3).toInt();
+  backlog.flags = value(4).toInt();
+  backlog.senderid = value(5).toInt();
+  backlog.message = value(6).toString();
+  return true;
+}
+
+bool SqliteMigrationReader::readMo(IrcServerMO &ircserver) {
+  if(!next())
+    return false;
+
+  ircserver.serverid = value(0).toInt();
+  ircserver.userid = value(1).toInt();
+  ircserver.networkid = value(2).toInt();
+  ircserver.hostname = value(3).toString();
+  ircserver.port = value(4).toInt();
+  ircserver.password = value(5).toString();
+  ircserver.ssl = value(6).toInt() == 1 ? true : false;
+  ircserver.sslversion = value(7).toInt();
+  ircserver.useproxy = value(8).toInt() == 1 ? true : false;
+  ircserver.proxytype = value(9).toInt();
+  ircserver.proxyhost = value(10).toString();
+  ircserver.proxyport = value(11).toInt();
+  ircserver.proxyuser = value(12).toString();
+  ircserver.proxypass = value(13).toString();
+  return true;
+}
+
+bool SqliteMigrationReader::readMo(UserSettingMO &userSetting) {
+  if(!next())
+    return false;
+
+  userSetting.userid = value(0).toInt();
+  userSetting.settingname = value(1).toString();
+  userSetting.settingvalue = value(2).toByteArray();
+
   return true;
 }