Shared random to world w/ thread safety fixes

sources/src/main/java/io/akarin/api/internal/Akari.java

@@ -70,7 +70,7 @@ public abstract class Akari {
     
     public static boolean isPrimaryThread(boolean assign) {
         Thread current = Thread.currentThread();
-        return current == MinecraftServer.getServer().primaryThread || (assign ? current instanceof AssignableThread : false);
+        return current == MinecraftServer.getServer().primaryThread || (assign ? (current.getClass() == AssignableThread.class) : false);
     }
     
     public static final String EMPTY_STRING = "";

sources/src/main/java/io/akarin/api/internal/mixin/IMixinWorldServer.java

@@ -1,5 +1,6 @@
 package io.akarin.api.internal.mixin;
 
-public interface IMixinLockProvider {
+public interface IMixinWorldServer {
     public Object lock();
+    public Object rand();
 }

sources/src/main/java/io/akarin/server/mixin/core/MixinMinecraftServer.java

@@ -27,7 +27,7 @@ import co.aikar.timings.MinecraftTimings;
 import co.aikar.timings.TimingHandler;
 import io.akarin.api.internal.Akari;
 import io.akarin.api.internal.Akari.AssignableFactory;
-import io.akarin.api.internal.mixin.IMixinLockProvider;
+import io.akarin.api.internal.mixin.IMixinWorldServer;
 import io.akarin.server.core.AkarinGlobalConfig;
 import io.akarin.server.core.AkarinSlackScheduler;
 import net.minecraft.server.BlockPosition;
@@ -241,7 +241,7 @@ public abstract class MixinMinecraftServer {
             entityWorld.timings.tickEntities.startTiming();
             WorldServer fEntityWorld = entityWorld;
 			Akari.STAGE_ENTITY_TICK.submit(() -> {
-				synchronized (((IMixinLockProvider) fEntityWorld).lock()) {
+				synchronized (((IMixinWorldServer) fEntityWorld).lock()) {
 					tickEntities(fEntityWorld);
 					fEntityWorld.getTracker().updatePlayers();
 					fEntityWorld.explosionDensityCache.clear(); // Paper - Optimize explosions
@@ -253,7 +253,7 @@ public abstract class MixinMinecraftServer {
                 WorldServer world = worlds.get(interlaceWorld);
                 world.timings.doTick.startTiming();
                 Akari.STAGE_WORLD_TICK.submit(() -> {
-                    synchronized (((IMixinLockProvider) world).lock()) {
+                    synchronized (((IMixinWorldServer) world).lock()) {
                         tickWorld(world);
                     }
                 }, world);
@@ -262,7 +262,7 @@ public abstract class MixinMinecraftServer {
         
         WorldServer primaryWorld = worlds.get(0);
         primaryWorld.timings.doTick.startTiming();
-        synchronized (((IMixinLockProvider) primaryWorld).lock()) {
+        synchronized (((IMixinWorldServer) primaryWorld).lock()) {
             tickWorld(primaryWorld);
         }
         primaryWorld.timings.doTick.stopTiming();

sources/src/main/java/io/akarin/server/mixin/core/MixinWorldServer.java

@@ -1,15 +1,37 @@
 package io.akarin.server.mixin.core;
 
+import java.util.Random;
+
+import org.apache.logging.log4j.LogManager;
 import org.spongepowered.asm.mixin.Mixin;
-import io.akarin.api.internal.mixin.IMixinLockProvider;
+import io.akarin.api.internal.mixin.IMixinWorldServer;
 import net.minecraft.server.WorldServer;
 
 @Mixin(value = WorldServer.class, remap = false)
-public abstract class MixinWorldServer implements IMixinLockProvider {
+public abstract class MixinWorldServer implements IMixinWorldServer {
     private final Object tickLock = new Object();
 
     @Override
     public Object lock() {
         return tickLock;
     }
+    
+    private final Random sharedRandom = new io.akarin.api.internal.utils.random.LightRandom() {
+        private static final long serialVersionUID = 1L;
+        private boolean locked = false;
+        @Override
+        public synchronized void setSeed(long seed) {
+            if (locked) {
+                LogManager.getLogger().error("Ignoring setSeed on Entity.SHARED_RANDOM", new Throwable());
+            } else {
+                super.setSeed(seed);
+                locked = true;
+            }
+        }
+    };
+    
+    @Override
+    public Random rand() {
+        return sharedRandom;
+    }
 }

sources/src/main/java/net/minecraft/server/Entity.java

@@ -27,6 +27,8 @@ import org.bukkit.entity.LivingEntity;
 import org.bukkit.entity.Vehicle;
 import co.aikar.timings.MinecraftTimings; // Paper
 import co.aikar.timings.Timing; // Paper
+import io.akarin.api.internal.mixin.IMixinWorldServer;
+
 import org.bukkit.event.entity.EntityCombustByEntityEvent;
 import org.bukkit.event.hanging.HangingBreakByEntityEvent;
 import org.bukkit.event.vehicle.VehicleBlockCollisionEvent;
@@ -51,7 +53,7 @@ public abstract class Entity implements ICommandListener, KeyedObject { // Paper
     // CraftBukkit start
     private static final int CURRENT_LEVEL = 2;
     // Paper start
-    public static Random SHARED_RANDOM = new io.akarin.api.internal.utils.random.LightRandom() { // Akarin - LightRNG
+    public static Random SHARED_RANDOM = new java.util.Random() {
         private boolean locked = false;
         @Override
         public synchronized void setSeed(long seed) {
@@ -208,7 +210,7 @@ public abstract class Entity implements ICommandListener, KeyedObject { // Paper
         this.length = 1.8F;
         this.ax = 1;
         this.ay = 1.0F;
-        this.random = SHARED_RANDOM; // Paper
+        this.random = ((IMixinWorldServer) world).rand(); // Paper // Akarin
         this.fireTicks = -this.getMaxFireTicks();
         this.justCreated = true;
         this.uniqueID = MathHelper.a(this.random);

sources/src/main/java/net/minecraft/server/RegistryID.java

@@ -9,7 +9,7 @@ import javax.annotation.Nullable;
 
 /**
  * Akarin Changes Note
- * 1) FastBitSet for faster access (performance)
+ * 1) BitSet for faster access (performance)
  */
 public class RegistryID<K> implements Registry {