Version bump

Manually perform idle updates. Fixed #160 #99

README.md

@@ -1,4 +1,4 @@
-# ViaVersion 0.5.8 
+# ViaVersion 0.6.2
 [![Build Status](https://travis-ci.org/MylesIsCool/ViaVersion.svg?branch=master)](https://travis-ci.org/MylesIsCool/ViaVersion)
 **Allows the connection of 1.9 clients to 1.8**
 
@@ -40,6 +40,8 @@ Contributors:
 
 **fillefilip8**
 
+**lenis0012**
+
 
 
 Releases / Dev Builds:
@@ -55,6 +57,9 @@ You can find unofficial dev builds here:
 
 **fillefilip8's Build Server:** http://build.fillecraft.com:8080/job/ViaVersion
 
+**sgdc3's Build Server:** http://ci.xephi.fr/job/ViaVersion/
+**sgdc3's Maven:** http://ci.xephi.fr/plugin/repository/everything/
+
 License:
 --------
 

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>us.myles</groupId>
     <artifactId>viaversion</artifactId>
-    <version>0.5.9-SNAPSHOT</version>
+    <version>0.6.3-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>ViaVersion</name>

src/main/java/org/spacehq/mc/protocol/util/NetUtil.java

@@ -47,18 +47,21 @@ public class NetUtil {
         // 2 = Get block light.
         // 3 = Get sky light.
         Chunk[] chunks = new Chunk[16];
-
+        int chunkCount = 0;
         for (int pass = 0; pass < 4; pass++) {
+            if(pass == 1){
+                if(chunkCount == 0) return null;
+            }
             for (int ind = 0; ind < 16; ind++) {
                 if ((bitmask & 1 << ind) != 0) {
                     if (pass == 0) {
+                        chunkCount++;
                         // Block length + Blocklight length
                         expected += (4096 * 2) + 2048;
                     }
 
                     if (pass == 1) {
                         chunks[ind] = new Chunk(sky || hasSkyLight);
-
                         buf.position(pos / 2);
                         int buffPos = buf.position();
                         // convert short array to new one

src/main/java/us/myles/ViaVersion/ConnectionInfo.java

@@ -12,6 +12,9 @@ import us.myles.ViaVersion.packets.State;
 @Getter
 @Setter
 public class ConnectionInfo {
+    private static final long IDLE_PACKET_DELAY = 50L; // Update every 50ms (20tps)
+    private static final long IDLE_PACKET_LIMIT = 20; // Max 20 ticks behind
+
     private final SocketChannel channel;
     private Object lastPacket;
     private java.util.UUID UUID;
@@ -22,6 +25,7 @@ public class ConnectionInfo {
     private int entityID;
     private boolean active = true;
     private String username;
+    private long nextIdlePacket = 0L;
 
     public ConnectionInfo(SocketChannel socketChannel) {
         this.channel = socketChannel;
@@ -33,6 +37,7 @@ public class ConnectionInfo {
 
     public void setActive(boolean active) {
         this.active = active;
+        this.nextIdlePacket = System.currentTimeMillis() + IDLE_PACKET_DELAY; // Update every 50 ticks
     }
 
     public void sendRawPacket(final ByteBuf packet, boolean currentThread) {
@@ -56,4 +61,10 @@ public class ConnectionInfo {
     public void closeWindow() {
         this.openWindow = null;
     }
+
+    public void incrementIdlePacket() {
+        // Notify of next update
+        // Allow a maximum lag spike of 1 second (20 ticks/updates)
+        this.nextIdlePacket = Math.max(nextIdlePacket + IDLE_PACKET_DELAY, System.currentTimeMillis() - IDLE_PACKET_DELAY * IDLE_PACKET_LIMIT);
+    }
 }

src/main/java/us/myles/ViaVersion/ViaIdleThread.java

@@ -0,0 +1,42 @@
+package us.myles.ViaVersion;
+
+import org.bukkit.scheduler.BukkitRunnable;
+import us.myles.ViaVersion.api.ViaVersion;
+import us.myles.ViaVersion.util.ReflectionUtil;
+
+import java.util.Map;
+import java.util.UUID;
+
+public class ViaIdleThread extends BukkitRunnable {
+    private final Map<UUID, ConnectionInfo> portedPlayers;
+    private final Class<?> idlePacketClass;
+
+    public ViaIdleThread(Map<UUID, ConnectionInfo> portedPlayers) {
+        this.portedPlayers = portedPlayers;
+        try {
+            this.idlePacketClass = ReflectionUtil.nms("PacketPlayInFlying");
+        } catch(ClassNotFoundException e) {
+            throw new RuntimeException("Couldn't find player idle packet, help!", e);
+        }
+    }
+
+    @Override
+    public void run() {
+        for(ConnectionInfo info : portedPlayers.values()) {
+            long nextIdleUpdate = info.getNextIdlePacket();
+            if(nextIdleUpdate <= System.currentTimeMillis()) {
+                try {
+                    Object packet = idlePacketClass.newInstance();
+                    info.getChannel().pipeline().fireChannelRead(packet);
+                } catch(InstantiationException | IllegalAccessException e) {
+                    System.out.println("Failed to create idle packet.");
+                    if(ViaVersion.getInstance().isDebug()) {
+                        e.printStackTrace();
+                    }
+                } finally {
+                    info.incrementIdlePacket();
+                }
+            }
+        }
+    }
+}

src/main/java/us/myles/ViaVersion/ViaVersionPlugin.java

@@ -4,7 +4,6 @@ import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelPipeline;
 import io.netty.channel.socket.SocketChannel;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
@@ -25,9 +24,11 @@ import us.myles.ViaVersion.handlers.ViaVersionInitializer;
 import us.myles.ViaVersion.listeners.CommandBlockListener;
 import us.myles.ViaVersion.update.UpdateListener;
 import us.myles.ViaVersion.update.UpdateUtil;
+import us.myles.ViaVersion.util.ListWrapper;
 import us.myles.ViaVersion.util.ReflectionUtil;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
@@ -53,8 +54,9 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
                 }
             }).get(10, TimeUnit.SECONDS);
         } catch (Exception e) {
-            System.out.println("Error fetching hand item ");
-            e.printStackTrace();
+            System.out.println("Error fetching hand item: " + e.getClass().getName());
+            if (ViaVersion.getInstance().isDebug())
+                e.printStackTrace();
             return null;
         }
     }
@@ -70,13 +72,10 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
         }
 
         getLogger().info("ViaVersion " + getDescription().getVersion() + " is now enabled, injecting. (Allows 1.8 to be accessed via 1.9)");
-        try {
-            injectPacketHandler();
-            System.setProperty("ViaVersion", getDescription().getVersion());
-        } catch (Exception e) {
-            getLogger().severe("Unable to inject handlers, are you on 1.8? ");
-            e.printStackTrace();
-        }
+        injectPacketHandler();
+        if (getConfig().getBoolean("simulate-pt", true))
+            new ViaIdleThread(portedPlayers).runTaskTimerAsynchronously(this, 1L, 1L); // Updates player's idle status
+
         if (getConfig().getBoolean("checkforupdates"))
             UpdateUtil.sendUpdateMessage(this);
 
@@ -94,39 +93,80 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
         getCommand("viaversion").setExecutor(new ViaVersionCommand(this));
     }
 
-    public void injectPacketHandler() throws Exception {
-        Class<?> serverClazz = ReflectionUtil.nms("MinecraftServer");
-        Object server = ReflectionUtil.invokeStatic(serverClazz, "getServer");
-        Object connection = serverClazz.getDeclaredMethod("getServerConnection").invoke(server);
-        // loop through all fields checking if list
-        boolean injected = false;
-        for (Field field : connection.getClass().getDeclaredFields()) {
-            field.setAccessible(true);
-            Object value = field.get(connection);
-            if (value instanceof List) {
-                for (Object o : (List) value) {
-                    if (o instanceof ChannelFuture) {
-                        ChannelFuture future = (ChannelFuture) o;
-                        ChannelPipeline pipeline = future.channel().pipeline();
-                        ChannelHandler bootstrapAcceptor = pipeline.first();
-                        try {
-                            ChannelInitializer<SocketChannel> oldInit = ReflectionUtil.get(bootstrapAcceptor, "childHandler", ChannelInitializer.class);
-                            ChannelInitializer newInit = new ViaVersionInitializer(oldInit);
-
-                            ReflectionUtil.set(bootstrapAcceptor, "childHandler", newInit);
-                        } catch (NoSuchFieldException e) {
-                            // field not found
-                            throw new Exception("Unable to find childHandler, blame " + bootstrapAcceptor.getClass().getName());
+    public void injectPacketHandler() {
+        try {
+            Class<?> serverClazz = ReflectionUtil.nms("MinecraftServer");
+            Object server = ReflectionUtil.invokeStatic(serverClazz, "getServer");
+            Object connection = serverClazz.getDeclaredMethod("getServerConnection").invoke(server);
+            if (connection == null) {
+                System.out.println("connection is null!!");
+                //try others
+                for (Method m : serverClazz.getDeclaredMethods()) {
+                    if (m.getReturnType() != null && !m.getName().equals("getServerConnection")) {
+                        if (m.getReturnType().getSimpleName().equals("ServerConnection")) {
+                            if (m.getParameterTypes().length == 0) {
+                                connection = m.invoke(server);
+                            }
+                        }
+                    }
+                }
+                if (connection == null) {
+                    getLogger().warning("We failed to find the ServerConnection? :(");
+                    return;
+                }
+            }
+            if (connection != null) {
+                for (Field field : connection.getClass().getDeclaredFields()) {
+                    field.setAccessible(true);
+                    final Object value = field.get(connection);
+                    if (value instanceof List) {
+                        // Inject the list
+                        List wrapper = new ListWrapper((List) value) {
+                            @Override
+                            public synchronized void handleAdd(Object o) {
+                                synchronized (this) {
+                                    if (o instanceof ChannelFuture) {
+                                        inject((ChannelFuture) o);
+                                    }
+                                }
+                            }
+                        };
+                        field.set(connection, wrapper);
+                        // Iterate through current list
+                        synchronized (wrapper) {
+                            for (Object o : (List) value) {
+                                if (o instanceof ChannelFuture) {
+                                    inject((ChannelFuture) o);
+                                } else {
+                                    break; // not the right list.
+                                }
+                            }
                         }
-                        injected = true;
-                    } else {
-                        break; // not the right list.
                     }
                 }
             }
+            System.setProperty("ViaVersion", getDescription().getVersion());
+        } catch (Exception e) {
+            getLogger().severe("Unable to inject handlers, are you on 1.8? ");
+            e.printStackTrace();
         }
-        if (!injected) {
-            throw new Exception("Could not find server to inject (Please ensure late-bind in your spigot.yml is false)");
+    }
+
+    private void inject(ChannelFuture future) {
+        try {
+            ChannelHandler bootstrapAcceptor = future.channel().pipeline().first();
+            try {
+                ChannelInitializer<SocketChannel> oldInit = ReflectionUtil.get(bootstrapAcceptor, "childHandler", ChannelInitializer.class);
+                ChannelInitializer newInit = new ViaVersionInitializer(oldInit);
+
+                ReflectionUtil.set(bootstrapAcceptor, "childHandler", newInit);
+            } catch (NoSuchFieldException e) {
+                // field not found
+                throw new Exception("Unable to find childHandler, blame " + bootstrapAcceptor.getClass().getName());
+            }
+        } catch (Exception e) {
+            getLogger().severe("Have you got late-bind enabled with something else? (ProtocolLib?)");
+            e.printStackTrace();
         }
     }
 
@@ -188,6 +228,18 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
         return getConfig().getBoolean("suppress-metadata-errors", false);
     }
 
+    public boolean isShieldBlocking() {
+        return getConfig().getBoolean("shield-blocking", true);
+    }
+
+    public boolean isHologramPatch() {
+        return getConfig().getBoolean("hologram-patch", false);
+    }
+
+    public double getHologramYOffset() {
+        return getConfig().getDouble("hologram-y", -1D);
+    }
+
     public boolean isAutoTeam() {
         // Collision has to be enabled first
         if (!isPreventCollision()) return false;
@@ -215,8 +267,9 @@ public class ViaVersionPlugin extends JavaPlugin implements ViaVersionAPI {
                 f.get(10, TimeUnit.SECONDS);
             }
         } catch (Exception e) {
-            System.out.println("Failed to run task.");
-            e.printStackTrace();
+            System.out.println("Failed to run task: " + e.getClass().getName());
+            if (ViaVersion.getInstance().isDebug())
+                e.printStackTrace();
         }
     }
 }

src/main/java/us/myles/ViaVersion/api/boss/BossBar.java

@@ -13,6 +13,13 @@ public interface BossBar {
      */
     void setTitle(String title);
 
+    /**
+     * Get the current title
+     *
+     * @return the title
+     */
+    String getTitle();
+
     /**
      * Change the health
      *
@@ -21,11 +28,11 @@ public interface BossBar {
     void setHealth(float health);
 
     /**
-     * Get the bossbar color
+     * Get the health
      *
-     * @return
+     * @return float between 0F - 1F
      */
-    BossColor getColor();
+    float getHealth();
 
     /**
      * Yay colors!
@@ -34,6 +41,13 @@ public interface BossBar {
      */
     void setColor(BossColor color);
 
+    /**
+     * Get the bossbar color
+     *
+     * @return
+     */
+    BossColor getColor();
+
     /**
      * Change the bosbar style
      *
@@ -41,6 +55,13 @@ public interface BossBar {
      */
     void setStyle(BossStyle style);
 
+    /**
+     * Get the bosbar style
+     *
+     * @return BossStyle
+     */
+    BossStyle getStyle();
+
     /**
      * Show the bossbar to a player.
      *

src/main/java/us/myles/ViaVersion/commands/ViaVersionCommand.java

@@ -20,16 +20,11 @@ public class ViaVersionCommand implements CommandExecutor {
 
     private final ViaVersionPlugin plugin;
 
-
     @Override
     public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
         if (sender.hasPermission("viaversion.admin")) {
             if (args.length == 0) {
-                sender.sendMessage(color("&aViaVersion &c" + ViaVersion.getInstance().getVersion()));
-                sender.sendMessage(color("&6Commands:"));
-                sender.sendMessage(color("&2/viaversion list &7- &6Shows lists of all 1.9 clients and 1.8 clients."));
-                sender.sendMessage(color("&2/viaversion autoteam &7- &6Toggle automatically teaming to prevent colliding."));
-                sender.sendMessage(color("&2/viaversion dontbugme &7- &6Toggle checking for updates."));
+                sendHelp(sender);
             } else if (args.length == 1) {
                 if (args[0].equalsIgnoreCase("list")) {
                     List<String> portedPlayers = new ArrayList<>();
@@ -59,11 +54,7 @@ public class ViaVersionCommand implements CommandExecutor {
                     sender.sendMessage(color("&6We will " + (newValue ? "&aautomatically team players" : "&cno longer auto team players")));
                     sender.sendMessage(color("&6All players will need to re-login for the change to take place."));
                 } else {
-                    sender.sendMessage(color("&aViaVersion &c" + ViaVersion.getInstance().getVersion()));
-                    sender.sendMessage(color("&6Commands:"));
-                    sender.sendMessage(color("&2/viaversion list &7- &6Shows lists of all 1.9 clients and 1.8 clients."));
-                    sender.sendMessage(color("&2/viaversion autoteam &7- &6Toggle automatically teaming to prevent colliding."));
-                    sender.sendMessage(color("&2/viaversion dontbugme &7- &6Toggle checking for updates."));
+                    sendHelp(sender);
                 }
             }
 
@@ -71,6 +62,15 @@ public class ViaVersionCommand implements CommandExecutor {
         return false;
     }
 
+    public void sendHelp(CommandSender sender){
+        sender.sendMessage(color("&aViaVersion &c" + ViaVersion.getInstance().getVersion()));
+        sender.sendMessage(color("&6Commands:"));
+        sender.sendMessage(color("&2/viaversion list &7- &6Shows lists of all 1.9 clients and 1.8 clients."));
+        sender.sendMessage(color("&2/viaversion debug &7- &6Toggle debug mode"));
+        sender.sendMessage(color("&2/viaversion autoteam &7- &6Toggle automatically teaming to prevent colliding."));
+        sender.sendMessage(color("&2/viaversion dontbugme &7- &6Toggle checking for updates."));
+    }
+
     public String color(String string) {
         return string.replace("&", "§");
     }

src/main/java/us/myles/ViaVersion/handlers/ViaDecodeHandler.java

@@ -34,7 +34,7 @@ public class ViaDecodeHandler extends ByteToMessageDecoder {
                     incomingTransformer.transform(id, bytebuf, newPacket);
                     bytebuf.clear();
                     bytebuf = newPacket;
-                } catch (CancelException e) {
+                } catch (Exception e) {
                     bytebuf.clear();
                     throw e;
                 }

src/main/java/us/myles/ViaVersion/handlers/ViaEncodeHandler.java

@@ -73,7 +73,7 @@ public class ViaEncodeHandler extends MessageToByteEncoder {
             bytebuf.clear();
             try {
                 outgoingTransformer.transform(id, oldPacket, bytebuf);
-            } catch (CancelException e) {
+            } catch (Exception e) {
                 bytebuf.clear();
                 throw e;
             } finally {

src/main/java/us/myles/ViaVersion/metadata/MetaIndex.java

@@ -33,6 +33,7 @@ public enum MetaIndex {
     PLAYER_HUMAN_BYTE(HumanEntity.class, 16, Type.Byte, NewType.Discontinued), // unused on 1.8
     PLAYER_ADDITIONAL_HEARTS(HumanEntity.class, 17, Type.Float, 10, NewType.Float),
     PLAYER_SCORE(HumanEntity.class, 18, Type.Int, 11, NewType.VarInt),
+    PLAYER_HAND(HumanEntity.class, -1, Type.NonExistent, 5, NewType.Byte), // new in 1.9
     // horse
     HORSE_INFO(Horse.class, 16, Type.Int, 12, NewType.Byte),
     HORSE_TYPE(Horse.class, 19, Type.Byte, 13, NewType.VarInt),

src/main/java/us/myles/ViaVersion/metadata/MetadataRewriter.java

@@ -40,6 +40,16 @@ public class MetadataRewriter {
                             if (metaIndex.getOldType() == Type.Int) {
                                 output.writeByte(((Integer) value).byteValue());
                             }
+                            // After writing the last one
+                            if (metaIndex == MetaIndex.ENTITY_STATUS && type == EntityType.PLAYER) {
+                                output.writeByte(MetaIndex.PLAYER_HAND.getNewIndex());
+                                output.writeByte(MetaIndex.PLAYER_HAND.getNewType().getTypeID());
+                                if ((((Byte) value) & 0x10) == 0x10) { // Player eating/aiming/drinking
+                                    output.writeByte(1); // Using main hand
+                                } else {
+                                    output.writeByte(0); // Not using any hand to stop animation
+                                }
+                            }
                             break;
                         case OptUUID:
                             String owner = (String) value;

src/main/java/us/myles/ViaVersion/metadata/Type.java

@@ -13,7 +13,8 @@ public enum Type {
     String(4),
     Slot(5),
     Position(6),
-    Rotation(7);
+    Rotation(7),
+    NonExistent(-1);
     private final int typeID;
 
     public static Type byId(int id) {

src/main/java/us/myles/ViaVersion/transformers/IncomingTransformer.java

@@ -16,6 +16,7 @@ import us.myles.ViaVersion.util.PacketUtil;
 import java.io.IOException;
 
 public class IncomingTransformer {
+    private final ViaVersionPlugin plugin = (ViaVersionPlugin) ViaVersion.getInstance();
     private final ConnectionInfo info;
     private boolean startedBlocking = false;
 
@@ -34,7 +35,7 @@ public class IncomingTransformer {
         if (packet.getPacketID() != -1) {
             packetID = packet.getPacketID();
         }
-        if (ViaVersion.getInstance().isDebug()) {
+        if (plugin.isDebug()) {
             if (packet != PacketType.PLAY_PLAYER_POSITION_LOOK_REQUEST && packet != PacketType.PLAY_KEEP_ALIVE_REQUEST && packet != PacketType.PLAY_PLAYER_POSITION_REQUEST && packet != PacketType.PLAY_PLAYER_LOOK_REQUEST) {
                 System.out.println("Direction " + packet.getDirection().name() + " Packet Type: " + packet + " New ID: " + packetID + " Original: " + original + " Size: " + input.readableBytes());
             }
@@ -42,6 +43,11 @@ public class IncomingTransformer {
         if (packet == PacketType.PLAY_TP_CONFIRM || packet == PacketType.PLAY_VEHICLE_MOVE_REQUEST) { //TODO handle client-sided horse riding
             throw new CancelException();
         }
+        // Handle movement increment
+        // Update idle status (player, position, look, positionandlook)
+        if(packet == PacketType.PLAY_PLAYER || packet == PacketType.PLAY_PLAYER_POSITION_REQUEST || packet == PacketType.PLAY_PLAYER_LOOK_REQUEST || packet == PacketType.PLAY_PLAYER_POSITION_LOOK_REQUEST) {
+            info.incrementIdlePacket();
+        }
         PacketUtil.writeVarInt(packetID, output);
         if (packet == PacketType.HANDSHAKE) {
             int protVer = PacketUtil.readVarInt(input);
@@ -267,7 +273,7 @@ public class IncomingTransformer {
             output.writeByte(face);
             PacketUtil.readVarInt(input);
 
-            ItemStack inHand = ViaVersionPlugin.getHandItem(info);
+            ItemStack inHand = plugin.getHandItem(info);
             try {
                 ItemSlotRewriter.ItemStack item = ItemSlotRewriter.ItemStack.fromBukkit(inHand);
                 ItemSlotRewriter.fixIdsFrom1_9To1_8(item);
@@ -275,14 +281,13 @@ public class IncomingTransformer {
             } catch (Exception e) {
                 e.printStackTrace();
             }
-
-            short curX = input.readUnsignedByte();
-            output.writeByte(curX);
-            short curY = input.readUnsignedByte();
-            output.writeByte(curY);
-            short curZ = input.readUnsignedByte();
-            output.writeByte(curZ);
-            return;
+	        short curX = input.readUnsignedByte();
+	        output.writeByte(curX);
+	        short curY = input.readUnsignedByte();
+	        output.writeByte(curY);
+	        short curZ = input.readUnsignedByte();
+	        output.writeByte(curZ);
+	        return;
         }
         if (packet == PacketType.PLAY_USE_ITEM) {
             int hand = PacketUtil.readVarInt(input);
@@ -292,8 +297,8 @@ public class IncomingTransformer {
             output.writeLong(-1L);
             output.writeByte(255);
             // write item in hand
-            ItemStack inHand = ViaVersionPlugin.getHandItem(info);
-            if (inHand != null) {
+            ItemStack inHand = plugin.getHandItem(info);
+            if (inHand != null && plugin.isShieldBlocking()) {
                 if (inHand.getType().name().endsWith("SWORD")) {
                     // blocking?
                     if (hand == 0) {
@@ -317,9 +322,9 @@ public class IncomingTransformer {
                 e.printStackTrace();
             }
 
-            output.writeByte(-1);
-            output.writeByte(-1);
-            output.writeByte(-1);
+            output.writeByte(0); //Is zero in 1.8, not -1
+            output.writeByte(0);
+            output.writeByte(0);
             return;
         }
         if (packet == PacketType.PLAY_CREATIVE_INVENTORY_ACTION) {

src/main/java/us/myles/ViaVersion/transformers/OutgoingTransformer.java

@@ -1,6 +1,7 @@
 package us.myles.ViaVersion.transformers;
 
 import io.netty.buffer.ByteBuf;
+import org.bukkit.Material;
 import org.bukkit.entity.EntityType;
 import org.json.simple.JSONObject;
 import org.json.simple.parser.JSONParser;
@@ -37,6 +38,8 @@ public class OutgoingTransformer {
     private final Map<Integer, UUID> uuidMap = new HashMap<>();
     private final Map<Integer, EntityType> clientEntityTypes = new HashMap<>();
     private final Map<Integer, Integer> vehicleMap = new HashMap<>();
+    private final Set<Integer> validBlocking = new HashSet<>();
+    private final Set<Integer> knownHolograms = new HashSet<>();
     private boolean autoTeam = false;
 
     public OutgoingTransformer(ConnectionInfo info) {
@@ -214,13 +217,15 @@ public class OutgoingTransformer {
             return;
         }
         if (packet == PacketType.PLAY_ENTITY_TELEPORT) {
-            // Port this so that it relative moves :P
             int id = PacketUtil.readVarInt(input);
             PacketUtil.writeVarInt(id, output);
 
             int x = input.readInt();
             output.writeDouble(x / 32D);
             int y = input.readInt();
+            if(plugin.isHologramPatch() & knownHolograms.contains(id)){
+                y = (int) ((y) + (plugin.getHologramYOffset() * 32D));
+            }
             output.writeDouble(y / 32D);
             int z = input.readInt();
             output.writeDouble(z / 32D);
@@ -241,6 +246,9 @@ public class OutgoingTransformer {
             int x = input.readByte();
             output.writeShort(x * 128);
             int y = input.readByte();
+            if(plugin.isHologramPatch() & knownHolograms.contains(id)){
+                y = (int) ((y) + plugin.getHologramYOffset());
+            }
             output.writeShort(y * 128);
             int z = input.readByte();
             output.writeShort(z * 128);
@@ -261,12 +269,16 @@ public class OutgoingTransformer {
             short x = (short) (input.readByte());
             output.writeShort(x * 128);
             short y = (short) (input.readByte());
+            if(plugin.isHologramPatch() & knownHolograms.contains(id)){
+                y = (short) (y - 1);
+            }
             output.writeShort(y * 128);
             short z = (short) (input.readByte());
             output.writeShort(z * 128);
 
             boolean onGround = input.readBoolean();
             output.writeBoolean(onGround);
+
             return;
 
         }
@@ -317,7 +329,24 @@ public class OutgoingTransformer {
                 slot += 1; // add 1 so it's now 2-5
             }
             PacketUtil.writeVarInt(slot, output);
-
+            if (slot == 0) {
+                // Read aheat for sword
+                input.markReaderIndex();
+                short itemID = input.readShort();
+                if (itemID != -1) {
+                    Material m = Material.getMaterial(itemID);
+                    if (m != null) {
+                        if (m.name().endsWith("SWORD")) {
+                            validBlocking.add(id);
+                        } else {
+                            validBlocking.remove(id);
+                        }
+                    }
+                } else {
+                    validBlocking.remove(id);
+                }
+                input.resetReaderIndex();
+            }
             ItemSlotRewriter.rewrite1_8To1_9(input, output);
             return;
         }
@@ -353,6 +382,7 @@ public class OutgoingTransformer {
             int[] toDestroy = PacketUtil.readVarInts(count, input);
             for (int entityID : toDestroy) {
                 clientEntityTypes.remove(entityID);
+                knownHolograms.remove(entityID);
                 PacketUtil.writeVarInt(entityID, output);
             }
             return;
@@ -751,6 +781,9 @@ public class OutgoingTransformer {
                 }
             }
             Column read = NetUtil.readOldChunkData(chunkX, chunkZ, groundUp, bitMask, data, true, sk);
+            if (read == null) {
+                throw new CancelException();
+            }
             // Write chunk section array :((
             ByteBuf temp = output.alloc().buffer();
             try {
@@ -808,14 +841,37 @@ public class OutgoingTransformer {
             if (entry.getOldID() == 0) {
                 // Byte
                 byte data = (byte) entry.getValue();
-                if ((data & 0x10) == 0x10) {
-                    ItemSlotRewriter.ItemStack shield = new ItemSlotRewriter.ItemStack();
-                    shield.id = 442;
-                    shield.amount = 1;
-                    shield.data = 0;
-                    sendSecondHandItem(entityID, shield);
-                } else {
-                    sendSecondHandItem(entityID, null);
+                if (entityID != info.getEntityID() && plugin.isShieldBlocking()) {
+                    if ((data & 0x10) == 0x10) {
+                        if (validBlocking.contains(entityID)) {
+                            ItemSlotRewriter.ItemStack shield = new ItemSlotRewriter.ItemStack();
+                            shield.id = 442;
+                            shield.amount = 1;
+                            shield.data = 0;
+                            sendSecondHandItem(entityID, shield);
+                        }
+                    } else {
+                        sendSecondHandItem(entityID, null);
+                    }
+                }
+            }
+        }
+        if(type == EntityType.ARMOR_STAND && plugin.isHologramPatch()){
+            if(entry.getOldID() == 0){
+                byte data = (byte) entry.getValue();
+                if((data & 0x20) == 0x20){
+                    if(!knownHolograms.contains(entityID)) {
+                        knownHolograms.add(entityID);
+                        // Send movement
+                        ByteBuf buf = info.getChannel().alloc().buffer();
+                        PacketUtil.writeVarInt(PacketType.PLAY_ENTITY_RELATIVE_MOVE.getNewPacketID(), buf);
+                        PacketUtil.writeVarInt(entityID, buf);
+                        buf.writeShort(0);
+                        buf.writeShort((short) (128D * (plugin.getHologramYOffset() * 32D)));
+                        buf.writeShort(0);
+                        buf.writeBoolean(true);
+                        info.sendRawPacket(buf, false);
+                    }
                 }
             }
         }

src/main/java/us/myles/ViaVersion/util/ListWrapper.java

@@ -0,0 +1,138 @@
+package us.myles.ViaVersion.util;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+
+public abstract class ListWrapper implements List {
+    private final List list;
+
+    public ListWrapper(List inputList) {
+        this.list = inputList;
+    }
+
+    public abstract void handleAdd(Object o);
+
+    @Override
+    public synchronized int size() {
+        return this.list.size();
+    }
+
+    @Override
+    public synchronized boolean isEmpty() {
+        return this.list.isEmpty();
+    }
+
+    @Override
+    public synchronized boolean contains(Object o) {
+        return this.list.contains(o);
+    }
+
+    @Override
+    public synchronized Iterator iterator() {
+        return this.list.iterator();
+    }
+
+    @Override
+    public synchronized Object[] toArray() {
+        return this.list.toArray();
+    }
+
+    @Override
+    public synchronized boolean add(Object o) {
+        handleAdd(o);
+        return this.list.add(o);
+    }
+
+    @Override
+    public synchronized boolean remove(Object o) {
+        return this.list.remove(o);
+    }
+
+    @Override
+    public synchronized boolean addAll(Collection c) {
+        for (Object o : c) {
+            handleAdd(o);
+        }
+        return this.list.addAll(c);
+    }
+
+    @Override
+    public synchronized boolean addAll(int index, Collection c) {
+        for (Object o : c) {
+            handleAdd(o);
+        }
+        return this.list.addAll(index, c);
+    }
+
+    @Override
+    public synchronized void clear() {
+        this.list.clear();
+    }
+
+    @Override
+    public synchronized Object get(int index) {
+        return this.list.get(index);
+    }
+
+    @Override
+    public synchronized Object set(int index, Object element) {
+        return this.list.set(index, element);
+    }
+
+    @Override
+    public synchronized void add(int index, Object element) {
+        this.list.add(index, element);
+    }
+
+    @Override
+    public synchronized Object remove(int index) {
+        return this.list.remove(index);
+    }
+
+    @Override
+    public synchronized int indexOf(Object o) {
+        return this.list.indexOf(o);
+    }
+
+    @Override
+    public synchronized int lastIndexOf(Object o) {
+        return this.list.lastIndexOf(o);
+    }
+
+    @Override
+    public synchronized ListIterator listIterator() {
+        return this.list.listIterator();
+    }
+
+    @Override
+    public synchronized ListIterator listIterator(int index) {
+        return this.list.listIterator(index);
+    }
+
+    @Override
+    public synchronized List subList(int fromIndex, int toIndex) {
+        return this.list.subList(fromIndex, toIndex);
+    }
+
+    @Override
+    public synchronized boolean retainAll(Collection c) {
+        return this.list.retainAll(c);
+    }
+
+    @Override
+    public synchronized boolean removeAll(Collection c) {
+        return this.list.removeAll(c);
+    }
+
+    @Override
+    public synchronized boolean containsAll(Collection c) {
+        return this.list.containsAll(c);
+    }
+
+    @Override
+    public synchronized Object[] toArray(Object[] a) {
+        return this.list.toArray(a);
+    }
+}

src/main/resources/config.yml

@@ -9,4 +9,13 @@ prevent-collision: true
 # If the above is true, should we automatically team players until you do?
 auto-team: true
 # When enabled if certain metadata can't be read we won't tell you about it
-suppress-metadata-errors: false
+suppress-metadata-errors: false
+# When enabled 1.9 will be able to block by using shields
+shield-blocking: true
+# Should we enable our hologram patch?
+# If they're in the wrong place enable this
+hologram-patch: false
+# This is the offset, should work as default when enabled.
+hologram-y: -1
+# Enable player tick simulation, this fixes eating, drinking, nether portals.
+simulate-pt: true