Async send keep alive packet

sources/src/main/java/io/akarin/server/core/AkarinSlackScheduler.java

@@ -1,9 +1,14 @@
 package io.akarin.server.core;
 
+import org.bukkit.entity.Player;
+
 import io.akarin.api.Akari;
+import net.minecraft.server.ChatMessage;
 import net.minecraft.server.EntityPlayer;
 import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.PacketPlayOutKeepAlive;
 import net.minecraft.server.PacketPlayOutUpdateTime;
+import net.minecraft.server.PlayerConnection;
 
 public class AkarinSlackScheduler extends Thread {
     public static AkarinSlackScheduler get() {
@@ -21,18 +26,47 @@ public class AkarinSlackScheduler extends Thread {
     private static class Singleton {
         private static final AkarinSlackScheduler instance = new AkarinSlackScheduler();
     }
+    
+    private long updateTime;
 
     @Override
     public void run() {
         MinecraftServer server = MinecraftServer.getServer();
         
         // Send time updates to everyone, it will get the right time from the world the player is in.
+        if (++updateTime == 10) {
+            for (EntityPlayer player : server.getPlayerList().players) {
+                player.playerConnection.sendPacket(new PacketPlayOutUpdateTime(player.world.getTime(), player.getPlayerTime(), player.world.getGameRules().getBoolean("doDaylightCycle"))); // Add support for per player time
+            }
+            updateTime = 0;
+        }
+        
         for (EntityPlayer player : server.getPlayerList().players) {
-            player.playerConnection.sendPacket(new PacketPlayOutUpdateTime(player.world.getTime(), player.getPlayerTime(), player.world.getGameRules().getBoolean("doDaylightCycle"))); // Add support for per player time
+            PlayerConnection conn = player.playerConnection;
+            // Paper - give clients a longer time to respond to pings as per pre 1.12.2 timings
+            // This should effectively place the keepalive handling back to "as it was" before 1.12.2
+            long currentTime = System.currentTimeMillis();
+            long elapsedTime = currentTime - conn.getLastPing();
+            if (conn.isPendingPing()) {
+                // We're pending a ping from the client
+                if (!conn.processedDisconnect && elapsedTime >= PlayerConnection.KEEPALIVE_LIMIT) { // check keepalive limit, don't fire if already disconnected
+                    Akari.callbackQueue.add(() -> {
+                        Akari.logger.warn("{} was kicked due to keepalive timeout!", conn.player.getName()); // more info
+                        conn.disconnect("disconnect.timeout");
+                    });
+                }
+            } else {
+                if (elapsedTime >= 15000L) { // 15 seconds
+                    conn.setPendingPing(true);
+                    conn.setLastPing(currentTime);
+                    conn.setKeepAliveID(currentTime);
+                    conn.sendPacket(new PacketPlayOutKeepAlive(conn.getKeepAliveID()));
+                }
+            }
         }
         
         try {
-            Thread.sleep(1000);
+            Thread.sleep(100);
         } catch (InterruptedException ex) {
             Akari.logger.warn("Slack scheduler thread was interrupted unexpectly!");
             ex.printStackTrace();

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

@@ -105,6 +105,11 @@ public class MixinMinecraftServer {
     
     @Overwrite
     public void D() throws InterruptedException {
+        Runnable runnable;
+        Akari.callbackTiming.startTiming();
+        while ((runnable = Akari.callbackQueue.poll()) != null) runnable.run();
+        Akari.callbackTiming.stopTiming();
+        
         MinecraftTimings.bukkitSchedulerTimer.startTiming();
         this.server.getScheduler().mainThreadHeartbeat(this.ticks);
         MinecraftTimings.bukkitSchedulerTimer.stopTiming();
@@ -117,7 +122,6 @@ public class MixinMinecraftServer {
         }
         MinecraftTimings.minecraftSchedulerTimer.stopTiming();
         
-        Runnable runnable;
         MinecraftTimings.processQueueTimer.startTiming();
         while ((runnable = processQueue.poll()) != null) runnable.run();
         MinecraftTimings.processQueueTimer.stopTiming();