Fix #42 Delay LevelChunkRegion removals by 20 ticks since last access

Author: PureGero

shreddedpaper-server/src/main/java/io/multipaper/shreddedpaper/region/LevelChunkRegion.java

@@ -2,7 +2,6 @@
 
 import ca.spottedleaf.concurrentutil.executor.queue.PrioritisedTaskQueue;
 import ca.spottedleaf.moonrise.common.list.IteratorSafeOrderedReferenceSet;
-import ca.spottedleaf.moonrise.common.util.TickThread;
 import it.unimi.dsi.fastutil.longs.LongLinkedOpenHashSet;
 import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
 import it.unimi.dsi.fastutil.objects.ObjectArrayList;
@@ -44,11 +43,18 @@ public class LevelChunkRegion {
     public final List<TickingBlockEntity> pendingBlockEntityTickers = new ReferenceArrayList<>();
     private final ObjectOpenHashSet<Mob> navigatingMobs = new ObjectOpenHashSet<>();
     private final ObjectLinkedOpenHashSet<BlockEventData> blockEvents = new ObjectLinkedOpenHashSet<>();
+    private volatile long lastAccessTick;
     public ArrayDeque<RedstoneTorchBlock.Toggle> redstoneUpdateInfos;
 
     public LevelChunkRegion(ServerLevel level, RegionPos regionPos) {
         this.level = level;
         this.regionPos = regionPos;
+
+        this.bumpLastAccess();
+    }
+
+    public void bumpLastAccess() {
+        this.lastAccessTick = this.level.levelData.getGameTime();
     }
 
     public synchronized void add(LevelChunk levelChunk) {
@@ -210,7 +216,8 @@ public synchronized void removeBlockEventsIf(Predicate<BlockEventData> predicate
     }
 
     public boolean isEmpty() {
-        return levelChunks.isEmpty()
+        return this.lastAccessTick < this.level.levelData.getGameTime() - 20
+                && levelChunks.isEmpty()
                 && playerTickingChunkRequests.isEmpty()
                 && tickingEntities.size() == 0
                 && scheduledTasks.isEmpty()

shreddedpaper-server/src/main/java/io/multipaper/shreddedpaper/region/LevelChunkRegionMap.java

@@ -43,7 +43,13 @@ public LevelChunkRegion getOrCreate(RegionPos regionPos) {
     }
 
     public LevelChunkRegion get(RegionPos regionPos) {
-        return regionsLock.optimisticRead(() -> regions.get(regionPos.longKey));
+        return regionsLock.optimisticRead(() -> {
+            LevelChunkRegion levelChunkRegion = regions.get(regionPos.longKey);
+            if (levelChunkRegion != null) {
+                levelChunkRegion.bumpLastAccess();
+            }
+            return levelChunkRegion;
+        });
     }
 
     public void remove(RegionPos regionPos) {