Better track time for unanalyzed CDJ-3000 tracks.

Author: brunchboy

CHANGELOG.md

@@ -15,6 +15,7 @@ This change log follows the conventions of
 - A setting has been added to the `TimeFinder` to prevent it from using precise position packets sent by CDJ-3000s.
   They help keep tighter synchronization with playback position, but currently seem to exhibit too much jitter for use when synchronizing with audio sources over Ableton Link.
   This setting is a workaround until a smoothing solution is developed.
+- When we are using precise position packets, though, we now do a better job of tracking the position of CDJ-3000s that are playing unanalyzed tracks (and which thus have no beat grids).
 - When we unexpectedly are unable to route a message to a CDJ, we now log extensive troubleshooting information about the address we are trying to send to and the state of the network interfaces at that moment.
 
 ### Fixed

src/main/java/org/deepsymmetry/beatlink/data/TimeFinder.java

@@ -566,8 +566,8 @@ private long timeOfBeat(BeatGrid beatGrid, int beatNumber, DeviceUpdate update)
             updates.put(device, beat);
             // logger.info("Beat: " + beat.getBeatWithinBar());
             final BeatGrid beatGrid = BeatGridFinder.getInstance().getLatestBeatGridFor(beat);
+            TrackPositionUpdate lastPosition = positions.get(device);
             if (beatGrid != null) {
-                TrackPositionUpdate lastPosition = positions.get(device);
                 int beatNumber;
                 if (lastPosition == null || lastPosition.beatGrid != beatGrid) {
                     // We don’t handle beat packets received before any status packets for the player. This will
@@ -594,8 +594,13 @@ private long timeOfBeat(BeatGrid beatGrid, int beatNumber, DeviceUpdate update)
                 positions.put(device, newPosition);
                 updateListenersIfNeeded(device, newPosition, beat);
             } else {
-                positions.remove(device);  // We can't determine where the player is.
-                updateListenersIfNeeded(device, null, beat);
+                // We can't determine where the player is. That's ok if it is sending us precise position packets,
+                // (e.g. a CDJ-3000 playing an unanalyzed track), we will just wait for the next one in that case.
+                // Otherwise, clear our notion of the playback position.
+                if (!lastPosition.precise) {
+                    positions.remove(device);
+                    updateListenersIfNeeded(device, null, beat);
+                }
             }
         }
     };