Fix libtorrent CMakeLists to always enable DHT mode

Close torrents when SyncWidget is closed

apps/Launcher/ext/libtorrent/CMakeLists.txt

@@ -121,7 +121,7 @@ set(ed25519_sources
 set(includes include ed25519/src)
 
 option(LIBTORRENT_pool-allocators "Uses a pool allocator for disk and piece buffers" ON)
-option(LIBTORRENT_dht "enable support for Mainline DHT" OFF)
+option(LIBTORRENT_dht "enable support for Mainline DHT" ON)
 option(LIBTORRENT_unicode "enable unicode support" ON)
 
 set(CMAKE_CONFIGURATION_TYPES Debug Release RelWithDebInfo)

apps/Launcher/syncwidget.cpp

@@ -138,11 +138,22 @@ SyncWidget::SyncWidget(QWidget* parent, Qt::WindowFlags f)
 }
 
 SyncWidget::~SyncWidget() {
+    libtorrent::entry dht = _session->dht_state();
+    std::string s = dht.to_string();
+
     openspace::DownloadManager::deinitialize();
     ghoul::deinitialize();
     delete _session;
 }
 
+void SyncWidget::closeEvent(QCloseEvent* event) {
+    std::vector<libtorrent::torrent_handle> handles = _session->get_torrents();
+    for (libtorrent::torrent_handle h : handles) {
+        h.flush_cache();
+        _session->remove_torrent(h);
+    }
+}
+
 void SyncWidget::setSceneFiles(QMap<QString, QString> sceneFiles) {
     _sceneFiles = std::move(sceneFiles);
     QStringList keys = _sceneFiles.keys();
@@ -601,3 +612,4 @@ void SyncWidget::handleFileFutureAddition(
     _futuresToAdd.insert(_futuresToAdd.end(), futures.begin(), futures.end());
     _mutex.clear();
 }
+

apps/Launcher/syncwidget.h

@@ -58,6 +58,8 @@ private slots:
     void syncButtonPressed();
     void handleTimer();
 
+    void closeEvent(QCloseEvent* event);
+
 private:
     struct DirectFile {
         QString module;