Various memory leak fixes

Plugins/Mineplex.Core/src/mineplex/core/memory/MemoryFix.java

@@ -1,20 +1,32 @@
 package mineplex.core.memory;
 
 import java.lang.reflect.Field;
+import java.util.HashSet;
 import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
 
 import mineplex.core.MiniPlugin;
 import mineplex.core.updater.UpdateType;
 import mineplex.core.updater.event.UpdateEvent;
 import net.minecraft.server.v1_8_R3.CraftingManager;
+import net.minecraft.server.v1_8_R3.Enchantment;
+import net.minecraft.server.v1_8_R3.EnchantmentManager;
 import net.minecraft.server.v1_8_R3.IInventory;
 
+import net.minecraft.server.v1_8_R3.WorldServer;
 import org.bukkit.Bukkit;
 import org.bukkit.World;
+import org.bukkit.block.Block;
 import org.bukkit.craftbukkit.v1_8_R3.CraftWorld;
 import org.bukkit.craftbukkit.v1_8_R3.entity.CraftPlayer;
+import org.bukkit.entity.Entity;
 import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
+import org.bukkit.event.entity.EntityDamageByBlockEvent;
+import org.bukkit.event.entity.EntityDamageByEntityEvent;
+import org.bukkit.event.entity.EntityDamageEvent;
 import org.bukkit.plugin.java.JavaPlugin;
 
 public class MemoryFix extends MiniPlugin
@@ -28,6 +40,151 @@ public class MemoryFix extends MiniPlugin
 		//_intHashMap = IntHashMap.class.	
 	}
 
+	@EventHandler
+	public void fixLastDamageEventLeaks(UpdateEvent event)
+	{
+		if (event.getType() != UpdateType.SLOW)
+			return;
+
+		List<World> worldList = Bukkit.getWorlds();
+		Set<World> worlds = new HashSet<>(worldList);
+
+		// Sanity check
+		if (worlds.size() != worldList.size())
+			throw new RuntimeException("Error: Duplicated worlds?!?!");
+
+
+		for (World world : worlds)
+		{
+			WorldServer worldServer = ((CraftWorld) world).getHandle();
+
+			for (net.minecraft.server.v1_8_R3.Entity nmsentity : worldServer.entityList)
+			{
+				Entity entity = nmsentity.getBukkitEntity();
+				EntityDamageEvent lastDamageCause = entity.getLastDamageCause();
+				if (lastDamageCause != null)
+				{
+					Entity damaged = lastDamageCause.getEntity();
+					Entity damagerEntity = null;
+					Block damagerBlock = null;
+					if (lastDamageCause instanceof EntityDamageByEntityEvent)
+						damagerEntity = ((EntityDamageByEntityEvent) lastDamageCause).getDamager();
+					if (lastDamageCause instanceof EntityDamageByBlockEvent)
+						damagerBlock = ((EntityDamageByBlockEvent) lastDamageCause).getDamager();
+
+					boolean shouldRemove = false;
+
+					if (!damaged.isValid())
+						shouldRemove = true;
+					else if (damagerEntity != null)
+					{
+						if (!damagerEntity.isValid())
+							shouldRemove = true;
+						else if (!worlds.contains(damagerEntity.getWorld()))
+							shouldRemove = true;
+					}
+					else if (damagerBlock != null)
+					{
+						if (!worlds.contains(damagerBlock.getWorld()))
+							shouldRemove = true;
+					}
+
+					if (shouldRemove)
+						entity.setLastDamageCause(null);
+				}
+			}
+		}
+	}
+
+	private static Object ENCHANTMENTMANAGER_D;
+	private static Field ENCHANTMENT_MODIFIER_THORNS_A;
+	private static Field ENCHANTMENT_MODIFIER_THORNS_B;
+	private static boolean ENCHANTMENTMANAGER_D_SUCCESFUL;
+
+	private static Object ENCHANTMENTMANAGER_E;
+	private static Field ENCHANTMENT_MODIFIER_ARTHROPODS_A;
+	private static Field ENCHANTMENT_MODIFIER_ARTHROPODS_B;
+	private static boolean ENCHANTMENTMANAGER_E_SUCCESFUL;
+
+	static
+	{
+		try
+		{
+			Field field = EnchantmentManager.class.getDeclaredField("d");
+			field.setAccessible(true);
+			ENCHANTMENTMANAGER_D = field.get(null);
+			ENCHANTMENT_MODIFIER_THORNS_A = ENCHANTMENTMANAGER_D.getClass().getDeclaredField("a");
+			ENCHANTMENT_MODIFIER_THORNS_A.setAccessible(true);
+			ENCHANTMENT_MODIFIER_THORNS_B = ENCHANTMENTMANAGER_D.getClass().getDeclaredField("b");
+			ENCHANTMENT_MODIFIER_THORNS_B.setAccessible(true);
+			ENCHANTMENTMANAGER_D_SUCCESFUL = true;
+		}
+		catch (ReflectiveOperationException e)
+		{
+			e.printStackTrace();
+		}
+		try
+		{
+			Field field = EnchantmentManager.class.getDeclaredField("e");
+			field.setAccessible(true);
+			ENCHANTMENTMANAGER_E = field.get(null);
+			ENCHANTMENT_MODIFIER_ARTHROPODS_A = ENCHANTMENTMANAGER_E.getClass().getDeclaredField("a");
+			ENCHANTMENT_MODIFIER_ARTHROPODS_A.setAccessible(true);
+			ENCHANTMENT_MODIFIER_ARTHROPODS_B = ENCHANTMENTMANAGER_E.getClass().getDeclaredField("b");
+			ENCHANTMENT_MODIFIER_ARTHROPODS_B.setAccessible(true);
+			ENCHANTMENTMANAGER_E_SUCCESFUL = true;
+		}
+		catch (ReflectiveOperationException e)
+		{
+			e.printStackTrace();
+		}
+	}
+
+	@EventHandler
+	public void fixEnchantmentManager(UpdateEvent event)
+	{
+		if (event.getType() != UpdateType.SLOW)
+			return;
+
+		if (ENCHANTMENTMANAGER_D_SUCCESFUL)
+		{
+			try
+			{
+				net.minecraft.server.v1_8_R3.Entity a = (net.minecraft.server.v1_8_R3.Entity) ENCHANTMENT_MODIFIER_THORNS_A.get(ENCHANTMENTMANAGER_D);
+				net.minecraft.server.v1_8_R3.Entity b = (net.minecraft.server.v1_8_R3.Entity) ENCHANTMENT_MODIFIER_THORNS_B.get(ENCHANTMENTMANAGER_D);
+
+				if ((a != null && !a.valid) || (b != null && !b.valid))
+				{
+					ENCHANTMENT_MODIFIER_THORNS_A.set(ENCHANTMENTMANAGER_D, null);
+					ENCHANTMENT_MODIFIER_THORNS_B.set(ENCHANTMENTMANAGER_D, null);
+				}
+			}
+			catch (ReflectiveOperationException e)
+			{
+				e.printStackTrace();
+			}
+		}
+
+		if (ENCHANTMENTMANAGER_E_SUCCESFUL)
+		{
+			try
+			{
+				net.minecraft.server.v1_8_R3.Entity a = (net.minecraft.server.v1_8_R3.Entity) ENCHANTMENT_MODIFIER_ARTHROPODS_A.get(ENCHANTMENTMANAGER_E);
+				net.minecraft.server.v1_8_R3.Entity b = (net.minecraft.server.v1_8_R3.Entity) ENCHANTMENT_MODIFIER_ARTHROPODS_B.get(ENCHANTMENTMANAGER_E);
+
+				if ((a != null && !a.valid) || (b != null && !b.valid))
+				{
+					ENCHANTMENT_MODIFIER_ARTHROPODS_A.set(ENCHANTMENTMANAGER_E, null);
+					ENCHANTMENT_MODIFIER_ARTHROPODS_B.set(ENCHANTMENTMANAGER_E, null);
+				}
+			}
+			catch (ReflectiveOperationException e)
+			{
+				e.printStackTrace();
+			}
+		}
+	}
+
 	@EventHandler
 	public void fixInventoryLeaks(UpdateEvent event)
 	{
@@ -36,17 +193,17 @@ public class MemoryFix extends MiniPlugin
 
 		for (World world : Bukkit.getWorlds())
 		{
-			for (Object tileEntity : ((CraftWorld)world).getHandle().tileEntityList)
+			for (Object tileEntity : ((CraftWorld) world).getHandle().tileEntityList)
 			{
 				if (tileEntity instanceof IInventory)
 				{
-					Iterator<HumanEntity> entityIterator = ((IInventory)tileEntity).getViewers().iterator();
+					Iterator<HumanEntity> entityIterator = ((IInventory) tileEntity).getViewers().iterator();
 
 					while (entityIterator.hasNext())
 					{
 						HumanEntity entity = entityIterator.next();
 
-						if (entity instanceof CraftPlayer && !((CraftPlayer)entity).isOnline())
+						if (entity instanceof CraftPlayer && !((CraftPlayer) entity).isOnline())
 						{
 							entityIterator.remove();
 						}