Return OptimisticNetworkManager

sources/src/main/java/io/akarin/server/mixin/nsc/OptimisticNetworkManager.java

@@ -0,0 +1,62 @@
+package io.akarin.server.mixin.nsc;
+
+import java.util.Queue;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Shadow;
+
+import com.googlecode.concurentlocks.ReentrantReadWriteUpdateLock;
+
+import io.akarin.api.internal.utils.CheckedConcurrentLinkedQueue;
+import io.netty.channel.Channel;
+import io.netty.util.concurrent.Future;
+import io.netty.util.concurrent.GenericFutureListener;
+import net.minecraft.server.NetworkManager;
+import net.minecraft.server.NetworkManager.QueuedPacket;
+import net.minecraft.server.Packet;
+import net.minecraft.server.PacketPlayOutMapChunk;
+
+@Mixin(value = NetworkManager.class, remap = false)
+public abstract class OptimisticNetworkManager {
+    @Shadow public Channel channel;
+    @Shadow(aliases = "i") @Final private Queue<NetworkManager.QueuedPacket> packets;
+    @Shadow(aliases = "j") @Final private ReentrantReadWriteUpdateLock queueLock;
+    
+    @Shadow public abstract Queue<NetworkManager.QueuedPacket> getPacketQueue();
+    @Shadow public abstract void dispatchPacket(Packet<?> packet, GenericFutureListener<? extends Future<? super Void>>[] genericFutureListeners);
+    
+    @SuppressWarnings("unchecked")
+    private static final QueuedPacket SIGNAL_PACKET = new QueuedPacket(null);
+    
+    @Overwrite // OBFHELPER: trySendQueue
+    private boolean m() {
+        if (this.channel != null && this.channel.isOpen()) {
+            if (this.packets.isEmpty()) { // return if the packet queue is empty so that the write lock by Anti-Xray doesn't affect the vanilla performance at all
+                return true;
+            }
+
+            this.queueLock.updateLock().lock();
+            try {
+                while (!this.packets.isEmpty()) {
+                    NetworkManager.QueuedPacket packet = ((CheckedConcurrentLinkedQueue<QueuedPacket>) getPacketQueue()).poll(item -> {
+                        return item.getPacket() instanceof PacketPlayOutMapChunk && !((PacketPlayOutMapChunk) item.getPacket()).isReady();
+                    }, SIGNAL_PACKET);
+                    
+                    if (packet != null) { // Fix NPE (Spigot bug caused by handleDisconnection())
+                        if (packet == SIGNAL_PACKET) {
+                            return false; // Return false if the peeked packet is a chunk packet which is not ready
+                        } else {
+                            dispatchPacket(packet.getPacket(), packet.getGenericFutureListeners()); // dispatch the packet
+                        }
+                    }
+                }
+            } finally {
+                this.queueLock.updateLock().unlock();
+            }
+            
+        }
+        return true; // Return true if all packets were dispatched
+    }
+    
+}