Correctly check for database needs to be updated

* Correctly check for database needs to be updated
* Create index only if not exists
* Double check whether database needs to be updated

PR #18638.

src/base/bittorrent/dbresumedatastorage.cpp

@@ -272,7 +272,7 @@ BitTorrent::DBResumeDataStorage::DBResumeDataStorage(const Path &dbPath, QObject
     else
     {
         const int dbVersion = (!db.record(DB_TABLE_TORRENTS).contains(DB_COLUMN_DOWNLOAD_PATH.name) ? 1 : currentDBVersion());
-        if (dbVersion != DB_VERSION)
+        if (dbVersion < DB_VERSION)
             updateDB(dbVersion);
     }
 
@@ -544,25 +544,35 @@ void BitTorrent::DBResumeDataStorage::updateDB(const int fromVersion) const
     try
     {
         if (fromVersion == 1)
+        {
+            const auto testQuery = u"SELECT COUNT(%1) FROM %2;"_qs
+                    .arg(quoted(DB_COLUMN_DOWNLOAD_PATH.name), quoted(DB_TABLE_TORRENTS));
+            if (!query.exec(testQuery))
             {
                 const auto alterTableTorrentsQuery = u"ALTER TABLE %1 ADD %2"_qs
                         .arg(quoted(DB_TABLE_TORRENTS), makeColumnDefinition(DB_COLUMN_DOWNLOAD_PATH, "TEXT"));
                 if (!query.exec(alterTableTorrentsQuery))
                     throw RuntimeError(query.lastError().text());
             }
+        }
 
         if (fromVersion <= 2)
+        {
+            const auto testQuery = u"SELECT COUNT(%1) FROM %2;"_qs
+                    .arg(quoted(DB_COLUMN_STOP_CONDITION.name), quoted(DB_TABLE_TORRENTS));
+            if (!query.exec(testQuery))
             {
                 const auto alterTableTorrentsQuery = u"ALTER TABLE %1 ADD %2"_qs
                         .arg(quoted(DB_TABLE_TORRENTS), makeColumnDefinition(DB_COLUMN_STOP_CONDITION, "TEXT NOT NULL DEFAULT `None`"));
                 if (!query.exec(alterTableTorrentsQuery))
                     throw RuntimeError(query.lastError().text());
             }
+        }
 
         if (fromVersion <= 3)
         {
             const QString torrentsQueuePositionIndexName = u"%1_%2_INDEX"_qs.arg(DB_TABLE_TORRENTS, DB_COLUMN_QUEUE_POSITION.name);
-            const QString createTorrentsQueuePositionIndexQuery = u"CREATE INDEX %1 ON %2 (%3)"_qs
+            const QString createTorrentsQueuePositionIndexQuery = u"CREATE INDEX IF NOT EXISTS %1 ON %2 (%3)"_qs
                     .arg(quoted(torrentsQueuePositionIndexName), quoted(DB_TABLE_TORRENTS), quoted(DB_COLUMN_QUEUE_POSITION.name));
             if (!query.exec(createTorrentsQueuePositionIndexQuery))
                 throw RuntimeError(query.lastError().text());