Resolve song from collection using track with Cue in XSPF

Fixes #1181

src/collection/collectionbackend.cpp

@@ -1210,6 +1210,36 @@ Song CollectionBackend::GetSongByUrl(const QUrl &url, const qint64 beginning) {
 
 }
 
+Song CollectionBackend::GetSongByUrlAndTrack(const QUrl &url, const int track) {
+
+  QMutexLocker l(db_->Mutex());
+  QSqlDatabase db(db_->Connect());
+
+  SqlQuery q(db);
+  q.prepare(QString("SELECT ROWID, %1 FROM %2 WHERE (url = :url1 OR url = :url2 OR url = :url3 OR url = :url4) AND track = :track AND unavailable = 0").arg(Song::kColumnSpec, songs_table_));
+
+  q.BindValue(":url1", url);
+  q.BindValue(":url2", url.toString());
+  q.BindValue(":url3", url.toString(QUrl::FullyEncoded));
+  q.BindValue(":url4", url.toEncoded());
+  q.BindValue(":track", track);
+
+  if (!q.Exec()) {
+    db_->ReportErrors(q);
+    return Song();
+  }
+
+  if (!q.next()) {
+    return Song();
+  }
+
+  Song song(source_);
+  song.InitFromQuery(q, true);
+
+  return song;
+
+}
+
 SongList CollectionBackend::GetSongsByUrl(const QUrl &url, const bool unavailable) {
 
   QMutexLocker l(db_->Mutex());

src/collection/collectionbackend.h

@@ -130,6 +130,7 @@ class CollectionBackendInterface : public QObject {
   // Returns a section of a song with the given filename and beginning. If the section is not present in collection, returns invalid song.
   // Using default beginning value is suitable when searching for single-section songs.
   virtual Song GetSongByUrl(const QUrl &url, const qint64 beginning = 0) = 0;
+  virtual Song GetSongByUrlAndTrack(const QUrl &url, const int track) = 0;
 
   virtual void AddDirectory(const QString &path) = 0;
   virtual void RemoveDirectory(const CollectionDirectory &dir) = 0;
@@ -203,6 +204,7 @@ class CollectionBackend : public CollectionBackendInterface {
 
   SongList GetSongsByUrl(const QUrl &url, const bool unavailable = false) override;
   Song GetSongByUrl(const QUrl &url, qint64 beginning = 0) override;
+  Song GetSongByUrlAndTrack(const QUrl &url, const int track) override;
 
   void AddDirectory(const QString &path) override;
   void RemoveDirectory(const CollectionDirectory &dir) override;