Import new trackers from magnet link in case of duplicate torrent (closes #111)

src/misc.cpp

@@ -309,7 +309,7 @@ QString misc::bcLinkToMagnet(QString bc_link) {
   return magnet;
 }
 
-QString misc::magnetUriToName(QString magnet_uri) {
+QString misc::magnetUriToName(const QString& magnet_uri) {
   QString name = "";
   QRegExp regHex("dn=([^&]+)");
   const int pos = regHex.indexIn(magnet_uri);
@@ -321,7 +321,23 @@ QString misc::magnetUriToName(QString magnet_uri) {
   return name;
 }
 
-QString misc::magnetUriToHash(QString magnet_uri) {
+QList<QUrl> misc::magnetUriToTrackers(const QString& magnet_uri)
+{
+  QList<QUrl> trackers;
+  QRegExp rx("tr=([^&]+)");
+  int pos = 0;
+
+  while ((pos = rx.indexIn(magnet_uri, pos)) != -1) {
+    const QUrl tracker = QUrl::fromEncoded(rx.cap(1).toUtf8());
+    qDebug() << Q_FUNC_INFO << "Found tracker: " << tracker.toString();
+    trackers << tracker;
+    pos += rx.matchedLength();
+  }
+
+  return trackers;
+}
+
+QString misc::magnetUriToHash(const QString& magnet_uri) {
   QString hash = "";
   QRegExp regHex("urn:btih:([0-9A-Za-z]+)");
   // Hex

src/misc.h

@@ -42,6 +42,7 @@
 #include <QPoint>
 #include <QFile>
 #include <QDir>
+#include <QUrl>
 #include <QCoreApplication>
 #ifndef DISABLE_GUI
 #include <QIcon>
@@ -99,8 +100,9 @@ public:
   // value must be given in bytes
   static QString friendlyUnit(qreal val, bool is_speed = false);
   static bool isPreviewable(QString extension);
-  static QString magnetUriToName(QString magnet_uri);
+  static QString magnetUriToName(const QString& magnet_uri);
-  static QString magnetUriToHash(QString magnet_uri);
+  static QString magnetUriToHash(const QString& magnet_uri);
+  static QList<QUrl> magnetUriToTrackers(const QString& magnet_uri);
   static QString bcLinkToMagnet(QString bc_link);
   // Take a number of seconds and return an user-friendly
   // time duration like "1d 2h 10m".

src/qtlibtorrent/qbtsession.cpp

@@ -921,6 +921,11 @@ QTorrentHandle QBtSession::addMagnetUri(QString magnet_uri, bool resumed, bool f
   if (s->find_torrent(QStringToSha1(hash)).is_valid()) {
     qDebug("/!\\ Torrent is already in download list");
     addConsoleMessage(tr("'%1' is already in download list.", "e.g: 'xxx.avi' is already in download list.").arg(magnet_uri));
+    // Check if the torrent contains trackers or url seeds we don't know about
+    // and add them
+    QTorrentHandle h_ex = getTorrentHandle(hash);
+    mergeTorrents(h_ex, magnet_uri);
+
     return h;
   }
 
@@ -1301,6 +1306,29 @@ void QBtSession::loadTorrentTempData(QTorrentHandle &h, QString savePath, bool m
     TorrentPersistentData::saveTorrentPersistentData(h, savePath, magnet);
 }
 
+void QBtSession::mergeTorrents(QTorrentHandle& h_ex, const QString& magnet_uri)
+{
+  QList<QUrl> new_trackers = misc::magnetUriToTrackers(magnet_uri);
+  bool trackers_added = false;
+  foreach (const QUrl& new_tracker, new_trackers) {
+    bool found = false;
+    std::vector<announce_entry> existing_trackers = h_ex.trackers();
+    foreach (const announce_entry& existing_tracker, existing_trackers) {
+      if (new_tracker == QUrl(existing_tracker.url.c_str())) {
+        found = true;
+        break;
+      }
+    }
+
+    if (!found) {
+      h_ex.add_tracker(announce_entry(new_tracker.toString().toStdString()));
+      trackers_added = true;
+    }
+  }
+  if (trackers_added)
+    addConsoleMessage(tr("Note: new trackers were added to the existing torrent."));
+}
+
 void QBtSession::mergeTorrents(QTorrentHandle &h_ex, boost::intrusive_ptr<torrent_info> t) {
   // Check if the torrent contains trackers or url seeds we don't know about
   // and add them

src/qtlibtorrent/qbtsession.h

@@ -191,7 +191,8 @@ private slots:
   void sendNotificationEmail(const QTorrentHandle &h);
   void autoRunExternalProgram(const QTorrentHandle &h, bool async=true);
   void cleanUpAutoRunProcess(int);
-  void mergeTorrents(QTorrentHandle &h_ex, boost::intrusive_ptr<libtorrent::torrent_info> t);
+  void mergeTorrents(QTorrentHandle& h_ex, boost::intrusive_ptr<libtorrent::torrent_info> t);
+  void mergeTorrents(QTorrentHandle& h_ex, const QString& magnet_uri);
   void exportTorrentFile(const QTorrentHandle &h, TorrentExportFolder folder = RegularTorrentExportFolder);
   void initWebUi();
   void handleIPFilterParsed(int ruleCount);