Play the next track in a last.fm stream, and handle the end of stream properly

src/lastfmservice.cpp

@@ -13,7 +13,8 @@ const char* LastFMService::kSettingsGroup = "Last.fm";
 
 LastFMService::LastFMService(QObject* parent)
   : RadioService("Last.fm", parent),
-    tuner_(NULL)
+    tuner_(NULL),
+    initial_tune_(false)
 {
   lastfm::ws::ApiKey = "75d20fb472be99275392aefa2760ea09";
   lastfm::ws::SharedSecret = "d3072b60ae626be12be69448f5c46e70";
@@ -147,13 +148,35 @@ void LastFMService::StartLoading(const QUrl& url) {
   emit LoadingStarted();
 
   delete tuner_;
+
   last_url_ = url;
+  initial_tune_ = true;
   tuner_ = new lastfm::RadioTuner(lastfm::RadioStation(url));
+
   connect(tuner_, SIGNAL(trackAvailable()), SLOT(TunerTrackAvailable()));
   connect(tuner_, SIGNAL(error(lastfm::ws::Error)), SLOT(TunerError(lastfm::ws::Error)));
 }
 
+void LastFMService::LoadNext(const QUrl &) {
+  lastfm::Track track = tuner_->takeNextTrack();
+
+  if (track.isNull()) {
+    emit StreamFinished();
+    return;
+  }
+
+  emit StreamReady(last_url_, track.url());
+
+  Song metadata;
+  metadata.InitFromLastFM(track);
+  emit StreamMetadataFound(last_url_, metadata);
+}
+
 void LastFMService::TunerError(lastfm::ws::Error error) {
+  qDebug() << "Last.fm error" << error;
+  if (!initial_tune_)
+    return;
+
   emit LoadingFinished();
 
   if (error == lastfm::ws::NotEnoughContent) {
@@ -162,7 +185,6 @@ void LastFMService::TunerError(lastfm::ws::Error error) {
   }
 
   emit StreamError(ErrorString(error));
-  qDebug() << "Last.fm error" << error;
 }
 
 QString LastFMService::ErrorString(lastfm::ws::Error error) const {
@@ -195,12 +217,10 @@ QString LastFMService::ErrorString(lastfm::ws::Error error) const {
 }
 
 void LastFMService::TunerTrackAvailable() {
-  emit LoadingFinished();
+  if (initial_tune_) {
+    emit LoadingFinished();
 
-  lastfm::Track track = tuner_->takeNextTrack();
-  emit StreamReady(last_url_, track.url());
-
-  Song metadata;
-  metadata.InitFromLastFM(track);
-  emit StreamMetadataFound(last_url_, metadata);
+    LoadNext(last_url_);
+    initial_tune_ = false;
+  }
 }

src/lastfmservice.h

@@ -27,7 +27,9 @@ class LastFMService : public RadioService {
   RadioItem* CreateRootItem(RadioItem* parent);
   void LazyPopulate(RadioItem *item);
   QList<RadioItem::PlaylistData> DataForItem(RadioItem* item);
+
   void StartLoading(const QUrl& url);
+  void LoadNext(const QUrl& url);
 
   void Authenticate(const QString& username, const QString& password);
 
@@ -49,6 +51,7 @@ class LastFMService : public RadioService {
   LastFMConfig* config_;
   lastfm::RadioTuner* tuner_;
   QUrl last_url_;
+  bool initial_tune_;
 };
 
 #endif // LASTFMSERVICE_H

src/player.cpp

@@ -17,7 +17,7 @@ Player::Player(Playlist* playlist, QObject* parent)
   SetVolume(settings_.value("volume", 50).toInt());
 
   connect(engine_, SIGNAL(stateChanged(Engine::State)), SLOT(EngineStateChanged(Engine::State)));
-  connect(engine_, SIGNAL(trackEnded()), SLOT(Next()));
+  connect(engine_, SIGNAL(trackEnded()), SLOT(TrackEnded()));
 }
 
 void Player::Next() {
@@ -32,6 +32,20 @@ void Player::Next() {
   PlayAt(i);
 }
 
+void Player::TrackEnded() {
+  int i = playlist_->current_item();
+  if (i == -1) {
+    Stop();
+    return;
+  }
+
+  // Is this track a radio station (like Last.fm) that can have another track?
+  if (playlist_->item_at(i)->LoadNext())
+    return;
+
+  Next();
+}
+
 void Player::PlayPause() {
   switch (engine_->state()) {
   case Engine::Paused:

src/player.h

@@ -27,6 +27,7 @@ class Player : public QObject {
   void Stop();
   void SetVolume(int value);
 
+  void TrackEnded();
   void StreamReady(const QUrl& original_url, const QUrl& media_url);
 
  signals:

src/playlistitem.h

@@ -39,6 +39,10 @@ class PlaylistItem {
   virtual bool StartLoading() { return false; }
   virtual QUrl Url() = 0;
 
+  // If the item is a radio station that can play another song after one has
+  // finished then it should do so and return true
+  virtual bool LoadNext() { return false; }
+
   virtual void SetTemporaryMetadata(const Song& metadata) {Q_UNUSED(metadata)}
   virtual void ClearTemporaryMetadata() {}
 };

src/radioplaylistitem.cpp

@@ -65,6 +65,14 @@ bool RadioPlaylistItem::StartLoading() {
   return true;
 }
 
+bool RadioPlaylistItem::LoadNext() {
+  if (service_) {
+    service_->LoadNext(url_);
+    return true;
+  }
+  return false;
+}
+
 QUrl RadioPlaylistItem::Url() {
   return url_;
 }

src/radioplaylistitem.h

@@ -27,6 +27,8 @@ class RadioPlaylistItem : public PlaylistItem {
   bool StartLoading();
   QUrl Url();
 
+  bool LoadNext();
+
   void SetTemporaryMetadata(const Song& metadata);
   void ClearTemporaryMetadata();
 

src/radioservice.h

@@ -22,7 +22,9 @@ class RadioService : public QObject {
   virtual void LazyPopulate(RadioItem* item) = 0;
 
   virtual QList<RadioItem::PlaylistData> DataForItem(RadioItem* item) = 0;
+
   virtual void StartLoading(const QUrl& url) = 0;
+  virtual void LoadNext(const QUrl& url) = 0;
 
  signals:
   void LoadingStarted();