Check for empty dimensions outside of chunk unloading loop, culling worlds without needing chunk unloads to trigger it. (#4704)

patches/minecraft/net/minecraft/world/gen/ChunkProviderServer.java.patch

@@ -72,7 +72,7 @@
                  Iterator<Long> iterator = this.field_73248_b.iterator();
  
                  for (int i = 0; i < 100 && iterator.hasNext(); iterator.remove())
-@@ -234,10 +267,15 @@
+@@ -234,6 +267,7 @@
                      if (chunk != null && chunk.field_189550_d)
                      {
                          chunk.func_76623_d();
@@ -80,11 +80,12 @@
                          this.func_73242_b(chunk);
                          this.func_73243_a(chunk);
                          this.field_73244_f.remove(olong);
-                         ++i;
+@@ -242,6 +276,8 @@
-+                        if (field_73244_f.size() == 0 && net.minecraftforge.common.ForgeChunkManager.getPersistentChunksFor(this.field_73251_h).size() == 0 && !this.field_73251_h.field_73011_w.func_186058_p().shouldLoadSpawn()){
-+                            net.minecraftforge.common.DimensionManager.unloadWorld(this.field_73251_h.field_73011_w.getDimension());
-+                            break;
-+                        }
-                     }
                  }
              }
+ 
++            if (this.field_73244_f.isEmpty()) net.minecraftforge.common.DimensionManager.unloadWorld(this.field_73251_h.field_73011_w.getDimension());
++
+             this.field_73247_e.func_75817_a();
+         }
+ 

src/main/java/net/minecraftforge/common/DimensionManager.java

@@ -32,7 +32,9 @@ import java.util.concurrent.ConcurrentMap;
 
 import it.unimi.dsi.fastutil.ints.IntArrayList;
 import it.unimi.dsi.fastutil.ints.IntListIterator;
-import org.apache.logging.log4j.Level;
+import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
+import it.unimi.dsi.fastutil.ints.IntSet;
+import it.unimi.dsi.fastutil.ints.IntSets;
 
 import com.google.common.collect.HashMultiset;
 import com.google.common.collect.Lists;
@@ -50,7 +52,6 @@ import net.minecraft.world.WorldServer;
 import net.minecraft.world.WorldServerMulti;
 import net.minecraft.world.storage.ISaveHandler;
 import net.minecraftforge.event.world.WorldEvent;
-import net.minecraftforge.fml.common.FMLCommonHandler;
 import net.minecraftforge.fml.common.FMLLog;
 
 import javax.annotation.Nullable;
@@ -68,13 +69,15 @@ public class DimensionManager
         }
     }
 
-    private static Hashtable<Integer, WorldServer> worlds = new Hashtable<Integer, WorldServer>();
     private static boolean hasInit = false;
-    private static Hashtable<Integer, Dimension> dimensions = new Hashtable<Integer, Dimension>();
+
-    private static IntArrayList unloadQueue = new IntArrayList();
+    private static final Hashtable<Integer, WorldServer> worlds = new Hashtable<>();
-    private static BitSet dimensionMap = new BitSet(Long.SIZE << 4);
+    private static final Hashtable<Integer, Dimension> dimensions = new Hashtable<>();
-    private static ConcurrentMap<World, World> weakWorldMap = new MapMaker().weakKeys().weakValues().<World,World>makeMap();
+    private static final IntSet keepLoaded = IntSets.synchronize(new IntOpenHashSet());
-    private static Multiset<Integer> leakedWorlds = HashMultiset.create();
+    private static final IntArrayList unloadQueue = new IntArrayList();
+    private static final BitSet dimensionMap = new BitSet(Long.SIZE << 4);
+    private static final ConcurrentMap<World, World> weakWorldMap = new MapMaker().weakKeys().weakValues().makeMap();
+    private static final Multiset<Integer> leakedWorlds = HashMultiset.create();
 
     /**
      * Returns a list of dimensions associated with this DimensionType.
@@ -299,13 +302,35 @@ public class DimensionManager
     }
 
     /**
-     * Queues a dimension to unload.
+     * Sets if a dimension should stay loaded.
-     * If the dimension is already queued, it will reset the delay to unload
+     * @param dim  the dimension ID
+     * @param keep whether or not the dimension should be kept loaded
+     * @return true iff the dimension's status changed
+     */
+    public static boolean keepDimensionLoaded(int dim, boolean keep)
+    {
+        return keep ? keepLoaded.add(dim) : keepLoaded.remove(dim);
+    }
+
+    private static boolean canUnloadWorld(WorldServer world)
+    {
+        return ForgeChunkManager.getPersistentChunksFor(world).isEmpty()
+                && world.playerEntities.isEmpty()
+                && !world.provider.getDimensionType().shouldLoadSpawn()
+                && !keepLoaded.contains(world.provider.getDimension());
+    }
+
+    /**
+     * Queues a dimension to unload, if it can be unloaded.
+     * If the dimension is already queued, it will reset the delay to unload.
      * @param id The id of the dimension
      */
     public static void unloadWorld(int id)
     {
-        if(!unloadQueue.contains(id))
+        WorldServer world = worlds.get(id);
+        if (world == null || !canUnloadWorld(world)) return;
+
+        if (!unloadQueue.contains(id))
         {
             FMLLog.log.debug("Queueing dimension {} to unload", id);
             unloadQueue.add(id);
@@ -337,7 +362,8 @@ public class DimensionManager
             WorldServer w = worlds.get(id);
             queueIterator.remove();
             dimension.ticksWaited = 0;
-            if (w == null || !ForgeChunkManager.getPersistentChunksFor(w).isEmpty() || !w.playerEntities.isEmpty() || dimension.type.shouldLoadSpawn()) //Don't unload the world if the status changed
+            // Don't unload the world if the status changed
+            if (w == null || !canUnloadWorld(w))
             {
                 FMLLog.log.debug("Aborting unload for dimension {} as status changed", id);
                 continue;

src/main/java/net/minecraftforge/server/command/ChunkGenWorker.java

@@ -41,7 +41,7 @@ public class ChunkGenWorker implements IWorker
     private final int notificationFrequency;
     private int lastNotification = 0;
     private int genned = 0;
-    private Boolean loadSpawn;
+    private Boolean keepingLoaded;
 
     public ChunkGenWorker(ICommandSender listener, BlockPos start, int total, int dim, int interval)
     {
@@ -116,10 +116,9 @@ public class ChunkGenWorker implements IWorker
                 }
             }
             // While we work we don't want to cause world load spam so pause unloading the world.
-            if (loadSpawn == null)
+            if (keepingLoaded == null)
             {
-                loadSpawn = world.provider.getDimensionType().shouldLoadSpawn();
+                keepingLoaded = DimensionManager.keepDimensionLoaded(dim, true);
-                world.provider.getDimensionType().setLoadSpawn(true);
             }
 
             if (++lastNotification >= notificationFrequency)
@@ -159,7 +158,10 @@ public class ChunkGenWorker implements IWorker
         if (queue.size() == 0)
         {
             listener.sendMessage(TextComponentHelper.createComponentTranslation(listener, "commands.forge.gen.complete", genned, total, dim));
-            DimensionManager.getProviderType(dim).setLoadSpawn(loadSpawn);
+            if (keepingLoaded != null && keepingLoaded)
+            {
+                DimensionManager.keepDimensionLoaded(dim, false);
+            }
         }
     }
 }