- Fix a possible crash when pausing then deleting a torrent quickly

src/bittorrent.cpp

@@ -1264,6 +1264,7 @@ void bittorrent::readAlerts() {
     else if (save_resume_data_alert* p = dynamic_cast<save_resume_data_alert*>(a.get())) {
       QDir torrentBackup(misc::qBittorrentPath() + "BT_backup");
       QTorrentHandle h(p->handle);
+      if(h.is_valid()) {
         QString file = h.hash()+".fastresume";
         // Delete old fastresume file if necessary
         if(QFile::exists(file))
@@ -1276,6 +1277,7 @@ void bittorrent::readAlerts() {
           bencode(std::ostream_iterator<char>(out), *p->resume_data);
         }
       }
+    }
     else if (metadata_received_alert* p = dynamic_cast<metadata_received_alert*>(a.get())) {
       QTorrentHandle h(p->handle);
       if(h.is_valid()) {
@@ -1290,11 +1292,13 @@ void bittorrent::readAlerts() {
     }
     else if (file_error_alert* p = dynamic_cast<file_error_alert*>(a.get())) {
       QTorrentHandle h(p->handle);
+      if(h.is_valid()) {
         h.auto_managed(false);
         std::cerr << "File Error: " << p->message().c_str() << std::endl;
         if(h.is_valid())
           emit fullDiskError(h, misc::toQString(p->message()));
       }
+    }
     else if (dynamic_cast<listen_failed_alert*>(a.get())) {
       // Level: fatal
       addConsoleMessage(tr("Couldn't listen on any of the given ports."), QString::fromUtf8("red"));