Avoid waiting on a closed TrackHandler

Author: devgianlu

core/src/main/java/xyz/gianlu/librespot/player/Player.java

@@ -315,7 +315,7 @@ public void crossfadeNextTrack(@NotNull TrackHandler handler, @Nullable String u
             if (uri != null && !next.toSpotifyUri().equals(uri))
                 LOGGER.warn(String.format("Fade out track URI is different from next track URI! {next: %s, crossfade: %s}", next, uri));
 
-            if (preloadTrackHandler != null && preloadTrackHandler.isTrack(next)) {
+            if (preloadTrackHandler != null && preloadTrackHandler.isPlayable(next)) {
                 crossfadeHandler = preloadTrackHandler;
             } else {
                 LOGGER.warn("Did not preload crossfade track. That's bad.");
@@ -402,7 +402,7 @@ private void loadTrack(boolean play, @NotNull PushToMixerReason reason) {
         }
 
         PlayableId id = state.getCurrentPlayableOrThrow();
-        if (crossfadeHandler != null && crossfadeHandler.isTrack(id)) {
+        if (crossfadeHandler != null && crossfadeHandler.isPlayable(id)) {
             trackHandler = crossfadeHandler;
             if (preloadTrackHandler == crossfadeHandler) preloadTrackHandler = null;
             crossfadeHandler = null;
@@ -429,7 +429,7 @@ private void loadTrack(boolean play, @NotNull PushToMixerReason reason) {
                 events.dispatchPlaybackResumed();
             }
         } else {
-            if (preloadTrackHandler != null && preloadTrackHandler.isTrack(id)) {
+            if (preloadTrackHandler != null && preloadTrackHandler.isPlayable(id)) {
                 trackHandler = preloadTrackHandler;
                 preloadTrackHandler = null;
 
@@ -732,7 +732,7 @@ void dispatchTrackChanged() {
 
             Metadata.Track track;
             Metadata.Episode episode;
-            if (trackHandler.isTrack(id)) {
+            if (trackHandler.isPlayable(id)) {
                 track = trackHandler.track();
                 episode = trackHandler.episode();
             } else {

core/src/main/java/xyz/gianlu/librespot/player/PlayerRunner.java

@@ -442,11 +442,13 @@ public void run() {
                             handler.clearOut();
                             break;
                         case Stop:
-                            handler = loadedTracks.remove(cmd.id);
+                            handler = loadedTracks.get(cmd.id);
                             if (handler != null) handler.close();
                             break;
                         case Seek:
                             handler = loadedTracks.get(cmd.id);
+                            if (handler == null) break;
+
                             if (!handler.isReady())
                                 handler.waitReady();
 
@@ -546,6 +548,7 @@ private void clearOut() {
         }
 
         boolean isReady() {
+            if (closed) throw new IllegalStateException("The handler is closed!");
             return codec != null;
         }
 
@@ -656,12 +659,13 @@ public void close() {
             try {
                 clearOut();
                 if (codec != null) codec.close();
+                codec = null;
             } catch (IOException ignored) {
             }
         }
 
-        boolean isTrack(@NotNull PlayableId id) {
-            return playable.toSpotifyUri().equals(id.toSpotifyUri());
+        boolean isPlayable(@NotNull PlayableId id) {
+            return !closed && playable.toSpotifyUri().equals(id.toSpotifyUri());
         }
 
         void seek(int pos) {