- Fix a crash when scanned directory does not exist

src/bittorrent.cpp

@@ -1044,6 +1044,11 @@ void bittorrent::saveTrackerFile(QString hash) {
 // Enable directory scanning
 void bittorrent::enableDirectoryScanning(QString scan_dir) {
   if(!scan_dir.isEmpty()) {
+    QDir newDir(scan_dir);
+    if(!newDir.exists()) {
+      qDebug("Scan dir %s does not exist, create it", scan_dir.toUtf8().data());
+      newDir.mkpath(scan_dir);
+    }
     if(FSWatcher == 0) {
       FSMutex = new QMutex();
       FSWatcher = new QFileSystemWatcher(QStringList(scan_dir), this);
@@ -1051,8 +1056,11 @@ void bittorrent::enableDirectoryScanning(QString scan_dir) {
       // Initial scan
       scanDirectory(scan_dir);
     } else {
-      QString old_scan_dir = FSWatcher->directories().first();
+      QString old_scan_dir = "";
+      if(!FSWatcher->directories().empty())
+        old_scan_dir = FSWatcher->directories().first();
       if(old_scan_dir != scan_dir) {
+        if(!old_scan_dir.isEmpty())
           FSWatcher->removePath(old_scan_dir);
         FSWatcher->addPath(scan_dir);
         // Initial scan