Check that QIODevice::open() is successful, and explicitly call close()

src/playlist/playlist.cpp

@@ -1240,7 +1240,7 @@ QMimeData *Playlist::mimeData(const QModelIndexList &indexes) const {
   }
 
   QBuffer buf;
-  buf.open(QIODevice::WriteOnly);
+  if (!buf.open(QIODevice::WriteOnly)) return nullptr;
   QDataStream stream(&buf);
 
   const Playlist *self = this;

src/playlist/playlistbackend.cpp

@@ -294,6 +294,7 @@ PlaylistItemPtr PlaylistBackend::RestoreCueData(PlaylistItemPtr item, std::share
       if (!cue_file.open(QIODevice::ReadOnly)) return item;
 
       song_list = cue_parser.Load(&cue_file, cue_path, QDir(cue_path.section('/', 0, -2)));
+      cue_file.close();
       state->cached_cues_[cue_path] = song_list;
     }
     else {