transform chunk bulk packets

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

@@ -7,6 +7,7 @@ import lombok.Getter;
 import lombok.Setter;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
+import us.myles.ViaVersion.chunks.ChunkManager;
 import us.myles.ViaVersion.packets.State;
 
 @Getter
@@ -16,6 +17,7 @@ public class ConnectionInfo {
     private static final long IDLE_PACKET_LIMIT = 20; // Max 20 ticks behind
 
     private final SocketChannel channel;
+    private final ChunkManager chunkManager;
     private Object lastPacket;
     private java.util.UUID UUID;
     private State state = State.HANDSHAKE;
@@ -29,6 +31,7 @@ public class ConnectionInfo {
 
     public ConnectionInfo(SocketChannel socketChannel) {
         this.channel = socketChannel;
+        this.chunkManager = new ChunkManager(this);
     }
 
     public Player getPlayer() {

src/main/java/us/myles/ViaVersion/chunks/ChunkManager.java

@@ -1,5 +1,6 @@
 package us.myles.ViaVersion.chunks;
 
+import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -7,13 +8,13 @@ import org.bukkit.Bukkit;
 import us.myles.ViaVersion.ConnectionInfo;
 import us.myles.ViaVersion.util.PacketUtil;
 import us.myles.ViaVersion.util.ReflectionUtil;
+import us.myles.ViaVersion.util.ReflectionUtil.ClassReflection;
 
-import java.lang.reflect.Field;
-import java.lang.reflect.Method;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.ShortBuffer;
 import java.util.BitSet;
+import java.util.List;
 import java.util.Set;
 import java.util.logging.Level;
 
@@ -33,21 +34,54 @@ public class ChunkManager {
 
     private final ConnectionInfo info;
     private final Set<Long> loadedChunks = Sets.newConcurrentHashSet();
-    private Method getWorldHandle;
+    private final Set<Long> bulkChunks = Sets.newConcurrentHashSet();
-    private Method getChunkAt;
+
-    private Field getSections;
+    // Reflection
+    private static ClassReflection mapChunkBulkRef;
+    private static ClassReflection mapChunkRef;
+
+    static {
+        try {
+            mapChunkBulkRef = new ClassReflection(ReflectionUtil.nms("PacketPlayOutMapChunkBulk"));
+            mapChunkRef = new ClassReflection(ReflectionUtil.nms("PacketPlayOutMapChunk"));
+        } catch(Exception e) {
+            Bukkit.getLogger().log(Level.WARNING, "Failed to initialise chunk reflection", e);
+        }
+    }
 
     public ChunkManager(ConnectionInfo info) {
         this.info = info;
-
-        try {
-            this.getWorldHandle = ReflectionUtil.obc("CraftWorld").getDeclaredMethod("getHandle");
-            this.getChunkAt = ReflectionUtil.nms("World").getDeclaredMethod("getChunkAt", int.class, int.class);
-            this.getSections = ReflectionUtil.nms("Chunk").getDeclaredField("sections");
-            getSections.setAccessible(true);
-        } catch(Exception e) {
-            Bukkit.getLogger().log(Level.WARNING, "Failed to initialise chunk verification", e);
     }
+
+    /**
+     * Transform a map chunk bulk in to separate map chunk packets.
+     * These packets are registered  so that they will never be seen as unload packets.
+     *
+     * @param packet to transform
+     * @return List of chunk data packets
+     */
+    public List<Object> transformMapChunkBulk(Object packet) {
+        List<Object> list = Lists.newArrayList();
+        try {
+            int[] xcoords = mapChunkBulkRef.getFieldValue("a", packet, int[].class);
+            int[] zcoords = mapChunkBulkRef.getFieldValue("b", packet, int[].class);
+            Object[] chunkMaps = mapChunkBulkRef.getFieldValue("c", packet, Object[].class);
+            for(int i = 0; i < chunkMaps.length; i++) {
+                int x = xcoords[i];
+                int z = zcoords[i];
+                Object chunkMap = chunkMaps[i];
+                Object chunkPacket = mapChunkRef.newInstance();
+                mapChunkRef.setFieldValue("a", chunkPacket, x);
+                mapChunkRef.setFieldValue("b", chunkPacket, z);
+                mapChunkRef.setFieldValue("c", chunkPacket, chunkMap);
+                mapChunkRef.setFieldValue("d", chunkPacket, true); // Chunk bulk chunks are always ground-up
+                bulkChunks.add(toLong(x, z)); // Store for later
+                list.add(chunkPacket);
+            }
+        } catch(Exception e) {
+            Bukkit.getLogger().log(Level.WARNING, "Failed to transform chunk bulk", e);
+        }
+        return list;
     }
 
     /**
@@ -76,35 +110,15 @@ public class ChunkManager {
                 usedSections.set(i);
             }
         }
-
-        // Unloading & empty chunks
         int sectionCount = usedSections.cardinality(); // the amount of sections set
-        if(sectionCount == 0 && groundUp) {
+
-            if(loadedChunks.contains(chunkHash)) {
+        // If the chunk is from a chunk bulk, it is never an unload packet
+        // Other wise, if it has no data, it is :)
+        boolean isBulkPacket = bulkChunks.remove(chunkHash);
+        if(sectionCount == 0 && groundUp && !isBulkPacket && loadedChunks.contains(chunkHash)) {
             // This is a chunk unload packet
             loadedChunks.remove(chunkHash);
             return new Chunk(chunkX, chunkZ);
-            } else {
-                // Check if chunk data is invalid
-                try {
-                    Object nmsWorld = getWorldHandle.invoke(info.getPlayer().getWorld());
-                    Object nmsChunk = getChunkAt.invoke(info.getPlayer().getWorld());
-                    Object[] nmsSections = (Object[]) getSections.get(nmsChunk);
-
-                    // Check if chunk is actually empty
-                    boolean isEmpty = false;
-                    int i = 0;
-                    while(i < nmsSections.length) {
-                        if(!(isEmpty = nmsSections[i++] == null)) break;
-                    }
-                    if(isEmpty) {
-                        // not empty, LOL
-                        return null;
-                    }
-                } catch(Exception e) {
-                    Bukkit.getLogger().log(Level.WARNING, "Failed to verify chunk", e);
-                }
-            }
         }
 
         int startIndex = input.readerIndex();

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

@@ -26,24 +26,7 @@ public class ViaChunkHandler extends MessageToMessageEncoder {
             info.setLastPacket(o);
             /* This transformer is more for fixing issues which we find hard at packet level :) */
             if(o.getClass().getName().endsWith("PacketPlayOutMapChunkBulk") && info.isActive()) {
-                final int[] locX = ReflectionUtil.get(o, "a", int[].class);
+                list.addAll(info.getChunkManager().transformMapChunkBulk(o));
-                final int[] locZ = ReflectionUtil.get(o, "b", int[].class);
-                final Object world = ReflectionUtil.get(o, "world", ReflectionUtil.nms("World"));
-                Class<?> mapChunk = ReflectionUtil.nms("PacketPlayOutMapChunk");
-                final Constructor constructor = mapChunk.getDeclaredConstructor(ReflectionUtil.nms("Chunk"), boolean.class, int.class);
-                for(int i = 0; i < locX.length; i++) {
-                    int x = locX[i];
-                    int z = locZ[i];
-                    // world invoke function
-                    try {
-                        Object chunk = ReflectionUtil.nms("World").getDeclaredMethod("getChunkAt", int.class, int.class).invoke(world, x, z);
-                        Object packet = constructor.newInstance(chunk, true, 65535);
-                        list.add(packet);
-                    } catch(InstantiationException | InvocationTargetException | ClassNotFoundException | IllegalAccessException | NoSuchMethodException e) {
-                        e.printStackTrace();
-                    }
-                }
-
                 return;
             }
         }

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

@@ -42,7 +42,6 @@ public class OutgoingTransformer {
     private final ViaVersionPlugin plugin = (ViaVersionPlugin) ViaVersion.getInstance();
 
     private final ConnectionInfo info;
-    private final ChunkManager chunkManager;
     private final Map<Integer, UUID> uuidMap = new HashMap<>();
     private final Map<Integer, EntityType> clientEntityTypes = new HashMap<>();
     private final Map<Integer, Integer> vehicleMap = new HashMap<>();
@@ -54,7 +53,6 @@ public class OutgoingTransformer {
 
     public OutgoingTransformer(ConnectionInfo info) {
         this.info = info;
-        this.chunkManager = new ChunkManager(info);
     }
 
     public static String fixJson(String line) {
@@ -781,6 +779,7 @@ public class OutgoingTransformer {
         }
         if (packet == PacketType.PLAY_CHUNK_DATA) {
             // Read chunk
+            ChunkManager chunkManager = info.getChunkManager();
             Chunk chunk = chunkManager.readChunk(input);
             if(chunk == null) {
                 throw new CancelException();

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

@@ -1,10 +1,14 @@
 package us.myles.ViaVersion.util;
 
+import com.google.common.collect.Maps;
 import org.bukkit.Bukkit;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
 
 public class ReflectionUtil {
     private static String BASE = Bukkit.getServer().getClass().getPackage().getName();
@@ -50,4 +54,74 @@ public class ReflectionUtil {
         field.setAccessible(true);
         field.set(o, value);
     }
+
+    public static final class ClassReflection {
+        private final Class<?> handle;
+        private final Map<String, Field> fields = Maps.newConcurrentMap();
+        private final Map<String, Method> methods = Maps.newConcurrentMap();
+
+        public ClassReflection(Class<?> handle) {
+            this(handle, true);
+        }
+
+        public ClassReflection(Class<?> handle, boolean recursive) {
+            this.handle = handle;
+            scanFields(handle, recursive);
+            scanMethods(handle, recursive);
+        }
+
+        private void scanFields(Class<?> host, boolean recursive) {
+            if(host.getSuperclass() != null && recursive) {
+                scanFields(host.getSuperclass(), true);
+            }
+
+            for(Field field : host.getDeclaredFields()) {
+                field.setAccessible(true);
+                fields.put(field.getName(), field);
+            }
+        }
+
+        private void scanMethods(Class<?> host, boolean recursive) {
+            if(host.getSuperclass() != null && recursive) {
+                scanMethods(host.getSuperclass(), true);
+            }
+
+            for(Method method : host.getDeclaredMethods()) {
+                method.setAccessible(true);
+                methods.put(method.getName(), method);
+            }
+        }
+
+        public Object newInstance() throws IllegalAccessException, InstantiationException {
+            return handle.newInstance();
+        }
+
+        public Field getField(String name) {
+            return fields.get(name);
+        }
+
+        public void setFieldValue(String fieldName, Object instance, Object value) throws IllegalAccessException {
+            getField(fieldName).set(instance, value);
+        }
+
+        public <T> T getFieldValue(String fieldName, Object instance, Class<T> type) throws IllegalAccessException {
+            return type.cast(getField(fieldName).get(instance));
+        }
+
+        public <T> T invokeMethod(Class<T> type, String methodName, Object instance, Object... args) throws InvocationTargetException, IllegalAccessException {
+            return type.cast(getMethod(methodName).invoke(instance, args));
+        }
+
+        public Method getMethod(String name) {
+            return methods.get(name);
+        }
+
+        public Collection<Field> getFields() {
+            return Collections.unmodifiableCollection(fields.values());
+        }
+
+        public Collection<Method> getMethods() {
+            return Collections.unmodifiableCollection(methods.values());
+        }
+    }
 }