Handle changed block entities. Fixes banners,beds & flowerpots

common/src/main/java/us/myles/ViaVersion/api/minecraft/chunks/ChunkSection.java

@@ -9,6 +9,8 @@ public interface ChunkSection {
 
     void setBlock(int x, int y, int z, int type, int data);
 
+    void setFlatBlock(int x, int y, int z, int type);
+
     int getBlockId(int x, int y, int z);
 
     void writeBlocks(ByteBuf output) throws Exception;

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_9_1_2to1_9_3_4/chunks/ChunkSection1_9_3_4.java

@@ -3,7 +3,6 @@ package us.myles.ViaVersion.protocols.protocol1_9_1_2to1_9_3_4.chunks;
 import com.google.common.collect.Lists;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import lombok.Getter;
 import us.myles.ViaVersion.api.minecraft.chunks.ChunkSection;
 import us.myles.ViaVersion.api.minecraft.chunks.NibbleArray;
 import us.myles.ViaVersion.api.type.Type;
@@ -46,6 +45,25 @@ public class ChunkSection1_9_3_4 implements ChunkSection {
         setBlock(index(x, y, z), type, data);
     }
 
+    /**
+     * Set a flat block in the chunks
+     *
+     * @param x    Block X
+     * @param y    Block Y
+     * @param z    Block Z
+     * @param type The type of the block
+     */
+    @Override
+    public void setFlatBlock(int x, int y, int z, int type) {
+        int index = palette.indexOf(type);
+        if (index == -1) {
+            index = palette.size();
+            palette.add(type);
+        }
+
+        blocks[index(x, y, z)] = index;
+    }
+
     public int getBlockId(int x, int y, int z) {
         return getBlock(x, y, z) >> 4;
     }

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_9_3to1_9_1_2/chunks/ChunkSection1_9_1_2.java

@@ -3,7 +3,7 @@ package us.myles.ViaVersion.protocols.protocol1_9_3to1_9_1_2.chunks;
 import com.google.common.collect.Lists;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import lombok.Getter;
+import sun.reflect.generics.reflectiveObjects.NotImplementedException;
 import us.myles.ViaVersion.api.minecraft.chunks.ChunkSection;
 import us.myles.ViaVersion.api.minecraft.chunks.NibbleArray;
 import us.myles.ViaVersion.api.type.Type;
@@ -46,6 +46,11 @@ public class ChunkSection1_9_1_2 implements ChunkSection {
         setBlock(index(x, y, z), type, data);
     }
 
+    @Override
+    public void setFlatBlock(int x, int y, int z, int type) {
+        throw new NotImplementedException();
+    }
+
     public int getBlockId(int x, int y, int z) {
         return getBlock(x, y, z) >> 4;
     }

common/src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/chunks/ChunkSection1_9to1_8.java

@@ -3,6 +3,7 @@ package us.myles.ViaVersion.protocols.protocol1_9to1_8.chunks;
 import com.google.common.collect.Lists;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
+import sun.reflect.generics.reflectiveObjects.NotImplementedException;
 import us.myles.ViaVersion.api.minecraft.chunks.ChunkSection;
 import us.myles.ViaVersion.api.minecraft.chunks.NibbleArray;
 import us.myles.ViaVersion.api.type.Type;
@@ -46,6 +47,11 @@ public class ChunkSection1_9to1_8 implements ChunkSection {
         setBlock(index(x, y, z), type, data);
     }
 
+    @Override
+    public void setFlatBlock(int x, int y, int z, int type) {
+        throw new NotImplementedException();
+    }
+
     public int getBlockId(int x, int y, int z) {
         return getBlock(x, y, z) >> 4;
     }

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/ProtocolSnapshotTo1_12_2.java

@@ -2,6 +2,7 @@ package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2;
 
 import us.myles.ViaVersion.api.PacketWrapper;
 import us.myles.ViaVersion.api.data.UserConnection;
+import us.myles.ViaVersion.api.platform.providers.ViaProviders;
 import us.myles.ViaVersion.api.protocol.Protocol;
 import us.myles.ViaVersion.api.remapper.PacketHandler;
 import us.myles.ViaVersion.api.remapper.PacketRemapper;
@@ -13,6 +14,8 @@ import us.myles.ViaVersion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
 import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.packets.EntityPackets;
 import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.packets.InventoryPackets;
 import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.packets.WorldPackets;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.BlockEntityProvider;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage.BlockStorage;
 import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage.EntityTracker;
 import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage.TabCompleteTracker;
 
@@ -364,5 +367,11 @@ public class ProtocolSnapshotTo1_12_2 extends Protocol {
         userConnection.put(new TabCompleteTracker(userConnection));
         if (!userConnection.has(ClientWorld.class))
             userConnection.put(new ClientWorld(userConnection));
+        userConnection.put(new BlockStorage(userConnection));
+    }
+
+    @Override
+    protected void register(ViaProviders providers) {
+        providers.register(BlockEntityProvider.class, new BlockEntityProvider());
     }
 }

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/packets/EntityPackets.java

@@ -94,7 +94,6 @@ public class EntityPackets {
                         int entityId = wrapper.get(Type.VAR_INT, 0);
 
                         Entity1_12Types.EntityType entType = Entity1_12Types.EntityType.PLAYER;
-                        System.out.println("REGISTER PLAYER");
                         // Register Type ID
                         wrapper.user().get(EntityTracker.class).addEntity(entityId, entType);
                         MetadataRewriter.handleMetadata(entityId, entType, wrapper.get(Types1_13.METADATA_LIST, 0), wrapper.user());

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/packets/WorldPackets.java

@@ -1,7 +1,11 @@
 package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.packets;
 
+import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
 import us.myles.ViaVersion.api.PacketWrapper;
+import us.myles.ViaVersion.api.Via;
+import us.myles.ViaVersion.api.data.UserConnection;
 import us.myles.ViaVersion.api.minecraft.BlockChangeRecord;
+import us.myles.ViaVersion.api.minecraft.Position;
 import us.myles.ViaVersion.api.minecraft.chunks.Chunk;
 import us.myles.ViaVersion.api.minecraft.chunks.ChunkSection;
 import us.myles.ViaVersion.api.protocol.Protocol;
@@ -12,12 +16,38 @@ import us.myles.ViaVersion.packets.State;
 import us.myles.ViaVersion.protocols.protocol1_9_1_2to1_9_3_4.types.Chunk1_9_3_4Type;
 import us.myles.ViaVersion.protocols.protocol1_9_3to1_9_1_2.storage.ClientWorld;
 import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.MappingData;
-
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.BlockEntityProvider;
-import java.util.List;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage.BlockStorage;
 
 public class WorldPackets {
     public static void register(Protocol protocol) {
         // Outgoing packets
+        // Update Block Entity
+        protocol.registerOutgoing(State.PLAY, 0x09, 0x09, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                map(Type.POSITION); // 0 - Location
+                map(Type.UNSIGNED_BYTE); // 1 - Action
+                map(Type.NBT); // 2 - NBT data
+
+                handler(new PacketHandler() {
+                    @Override
+                    public void handle(PacketWrapper wrapper) throws Exception {
+                        Position position = wrapper.get(Type.POSITION, 0);
+                        CompoundTag tag = wrapper.get(Type.NBT, 0);
+
+                        BlockEntityProvider provider = Via.getManager().getProviders().get(BlockEntityProvider.class);
+                        int newId = provider.transform(wrapper.user(), position, tag, true);
+
+                        if (newId != -1) {
+                            BlockStorage storage = wrapper.user().get(BlockStorage.class);
+                            if (storage.contains(position))
+                                storage.get(position).setReplacement(newId);
+                        }
+                    }
+                });
+            }
+        });
 
         // Block Change
         protocol.registerOutgoing(State.PLAY, 0xB, 0xB, new PacketRemapper() {
@@ -28,7 +58,10 @@ public class WorldPackets {
                 handler(new PacketHandler() {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
-                        wrapper.set(Type.VAR_INT, 0, toNewId(wrapper.get(Type.VAR_INT, 0)));
+                        Position position = wrapper.get(Type.POSITION, 0);
+                        int newId = toNewId(wrapper.get(Type.VAR_INT, 0));
+
+                        wrapper.set(Type.VAR_INT, 0, checkStorage(wrapper.user(), position, newId));
                     }
                 });
             }
@@ -38,15 +71,24 @@ public class WorldPackets {
         protocol.registerOutgoing(State.PLAY, 0x10, 0xF, new PacketRemapper() {
             @Override
             public void registerMap() {
-                map(Type.INT);
+                map(Type.INT); // 0 - Chunk X
-                map(Type.INT);
+                map(Type.INT); // 1 - Chunk Z
-                map(Type.BLOCK_CHANGE_RECORD_ARRAY);
+                map(Type.BLOCK_CHANGE_RECORD_ARRAY); // 2 - Records
                 handler(new PacketHandler() {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
+                        BlockStorage storage = wrapper.user().get(BlockStorage.class);
+                        int chunkX = wrapper.get(Type.INT, 0);
+                        int chunkZ = wrapper.get(Type.INT, 0);
                         // Convert ids
                         for (BlockChangeRecord record : wrapper.get(Type.BLOCK_CHANGE_RECORD_ARRAY, 0)) {
-                            record.setBlockId(toNewId(record.getBlockId()));
+                            int newBlock = toNewId(record.getBlockId());
+                            Position position = new Position(
+                                    (long) (record.getHorizontal() >> 4 & 15) + (chunkX * 16),
+                                    (long) record.getY(),
+                                    (long) ((record.getHorizontal() & 15) + (chunkZ * 16)));
+
+                            record.setBlockId(checkStorage(wrapper.user(), position, newBlock));
                         }
                     }
                 });
@@ -64,17 +106,52 @@ public class WorldPackets {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         ClientWorld clientWorld = wrapper.user().get(ClientWorld.class);
+                        BlockStorage storage = wrapper.user().get(BlockStorage.class);
 
                         Chunk1_9_3_4Type type = new Chunk1_9_3_4Type(clientWorld);
                         Chunk chunk = wrapper.passthrough(type);
 
-                        // Remap palette ids
+                        for (int i = 0; i < chunk.getSections().length; i++) {
-                        for (ChunkSection section : chunk.getSections()) {
+                            ChunkSection section = chunk.getSections()[i];
-                            if (section == null) continue;
+                            if (section == null)
-                            List<Integer> palette = section.getPalette();
+                                continue;
-                            for (int i = 0; i < palette.size(); i++) {
+
-                                int newId = toNewId(palette.get(i));
+                            // TODO improve performance
-                                palette.set(i, newId);
+                            for (int x = 0; x < 16; x++) {
+                                for (int y = 0; y < 16; y++) {
+                                    for (int z = 0; z < 16; z++) {
+                                        int block = section.getBlock(x, y, z);
+
+                                        int newId = toNewId(block);
+                                        section.setFlatBlock(x, y, z, newId);
+
+                                        if (storage.isWelcome(newId)) {
+                                            storage.store(new Position(
+                                                    (long) (x + (chunk.getX() << 4)),
+                                                    (long) (y + (i << 4)),
+                                                    (long) (z + (chunk.getZ() << 4))
+                                            ), newId);
+                                        }
+                                    }
+                                }
+                            }
+                        }
+
+                        // Rewrite BlockEntities to normal blocks
+                        BlockEntityProvider provider = Via.getManager().getProviders().get(BlockEntityProvider.class);
+                        for (CompoundTag tag : chunk.getBlockEntities()) {
+                            int newId = provider.transform(wrapper.user(), null, tag, false);
+                            if (newId != -1) {
+                                int x = (int) tag.get("x").getValue() & 0xF;
+                                int y = (int) tag.get("y").getValue();
+                                int z = (int) tag.get("z").getValue() & 0xF;
+
+                                Position position = new Position((long) x, (long) y, (long) z);
+                                // Store the replacement blocks for blockupdates
+                                if (storage.contains(position))
+                                    storage.get(position).setReplacement(newId);
+
+                                chunk.getSections()[y >> 4].setFlatBlock(x, y, z, newId);
                             }
                         }
                     }
@@ -111,4 +188,23 @@ public class WorldPackets {
         }
     }
 
+    private static int checkStorage(UserConnection user, Position position, int newId) {
+        BlockStorage storage = user.get(BlockStorage.class);
+        if (storage.contains(position)) {
+            BlockStorage.ReplacementData data = storage.get(position);
+
+            if (data.getOriginal() == newId) {
+                if (data.getReplacement() != -1) {
+                    return data.getReplacement();
+                }
+            } else {
+                storage.remove(position);
+                // Check if the new id has to be stored
+                if (storage.isWelcome(newId))
+                    storage.store(position, newId);
+            }
+        } else if (storage.isWelcome(newId))
+            storage.store(position, newId);
+        return newId;
+    }
 }

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/providers/BlockEntityProvider.java

@@ -0,0 +1,68 @@
+package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers;
+
+import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
+import us.myles.ViaVersion.api.PacketWrapper;
+import us.myles.ViaVersion.api.data.UserConnection;
+import us.myles.ViaVersion.api.minecraft.Position;
+import us.myles.ViaVersion.api.platform.providers.Provider;
+import us.myles.ViaVersion.api.type.Type;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.ProtocolSnapshotTo1_12_2;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.blockentities.BannerHandler;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.blockentities.BedHandler;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.blockentities.FlowerPotHandler;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class BlockEntityProvider implements Provider {
+    private final Map<String, BlockEntityHandler> handlers = new ConcurrentHashMap<>();
+
+    public BlockEntityProvider() {
+        handlers.put("minecraft:flower_pot", new FlowerPotHandler());
+        handlers.put("minecraft:bed", new BedHandler());
+        handlers.put("minecraft:banner", new BannerHandler());
+    }
+
+    /**
+     * Transforms the BlockEntities to blocks!
+     *
+     * @param user       UserConnection instance
+     * @param position   Block Position - WARNING: Position is null when called from a chunk
+     * @param tag        BlockEntity NBT
+     * @param sendUpdate send a block change update
+     * @return new block id
+     * @throws Exception Gotta throw that exception
+     */
+    public int transform(UserConnection user, Position position, CompoundTag tag, boolean sendUpdate) throws Exception {
+        if (!tag.contains("id"))
+            return -1;
+
+        String id = (String) tag.get("id").getValue();
+
+        if (!handlers.containsKey(id)) {
+            System.out.println("Unhandled BlockEntity " + id + " full tag: " + tag);
+            return -1;
+        }
+
+        int newBlock = handlers.get(id).transform(user, tag);
+
+        if (sendUpdate && newBlock != -1)
+            sendBlockChange(user, position, newBlock);
+
+        return newBlock;
+    }
+
+    public interface BlockEntityHandler {
+        int transform(UserConnection user, CompoundTag tag);
+    }
+
+    private void sendBlockChange(UserConnection user, Position position, int blockId) throws Exception {
+        PacketWrapper wrapper = new PacketWrapper(0x0B, null, user);
+        wrapper.write(Type.POSITION, position);
+        wrapper.write(Type.VAR_INT, blockId);
+
+        wrapper.send(ProtocolSnapshotTo1_12_2.class);
+    }
+
+
+}

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/providers/blockentities/BannerHandler.java

@@ -0,0 +1,45 @@
+package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.blockentities;
+
+import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
+import com.github.steveice10.opennbt.tag.builtin.Tag;
+import us.myles.ViaVersion.api.data.UserConnection;
+import us.myles.ViaVersion.api.minecraft.Position;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.BlockEntityProvider;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage.BlockStorage;
+
+public class BannerHandler implements BlockEntityProvider.BlockEntityHandler {
+    private final int WALL_BANNER_START = 5633; // 4 each
+    private final int WALL_BANNER_STOP = 5696;
+
+    private final int BANNER_START = 5377; // 16 each
+    private final int BANNER_STOP = 5632;
+
+    @Override
+    public int transform(UserConnection user, CompoundTag tag) {
+        BlockStorage storage = user.get(BlockStorage.class);
+        Position position = new Position(getLong(tag.get("x")), getLong(tag.get("y")), getLong(tag.get("z")));
+
+        if (!storage.contains(position)) {
+            System.out.println("Received an banner color update packet, but there is no banner! O_o " + tag);
+            return -1;
+        }
+
+        int blockId = storage.get(position).getOriginal();
+
+        int color = (int) tag.get("Base").getValue();
+        // Standing banner
+        if (blockId >= BANNER_START && blockId <= BANNER_STOP)
+            blockId += ((15 - color) * 16);
+            // Wall banner
+        else if (blockId >= WALL_BANNER_START && blockId <= WALL_BANNER_STOP)
+            blockId += ((15 - color) * 4);
+        else
+            System.out.println("Why does this block have the banner block entity? :(" + tag);
+
+        return blockId;
+    }
+
+    private long getLong(Tag tag) {
+        return ((Integer) tag.getValue()).longValue();
+    }
+}

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/providers/blockentities/BedHandler.java

@@ -0,0 +1,34 @@
+package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.blockentities;
+
+import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
+import com.github.steveice10.opennbt.tag.builtin.Tag;
+import us.myles.ViaVersion.api.data.UserConnection;
+import us.myles.ViaVersion.api.minecraft.Position;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.BlockEntityProvider;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage.BlockStorage;
+
+public class BedHandler implements BlockEntityProvider.BlockEntityHandler {
+
+    @Override
+    public int transform(UserConnection user, CompoundTag tag) {
+        BlockStorage storage = user.get(BlockStorage.class);
+        Position position = new Position(getLong(tag.get("x")), getLong(tag.get("y")), getLong(tag.get("z")));
+
+        if (!storage.contains(position)) {
+            System.out.println("Received an bed color update packet, but there is no bed! O_o " + tag);
+            return -1;
+        }
+
+        //                                RED_BED + FIRST_BED
+        int blockId = storage.get(position).getOriginal() - 896 + 672;
+
+        int color = (int) tag.get("color").getValue();
+        blockId += (color * 16);
+
+        return blockId;
+    }
+
+    private long getLong(Tag tag) {
+        return ((Integer) tag.getValue()).longValue();
+    }
+}

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/providers/blockentities/FlowerPotHandler.java

@@ -0,0 +1,59 @@
+package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.blockentities;
+
+import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
+import us.myles.ViaVersion.api.Pair;
+import us.myles.ViaVersion.api.data.UserConnection;
+import us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.providers.BlockEntityProvider;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class FlowerPotHandler implements BlockEntityProvider.BlockEntityHandler {
+    private static final Map<Pair<String, Integer>, Integer> flowers = new ConcurrentHashMap<>();
+
+    static {
+        register("minecraft:air", 0, 4466);
+        register("minecraft:sapling", 0, 4467);
+        register("minecraft:sapling", 1, 4468);
+        register("minecraft:sapling", 2, 4469);
+        register("minecraft:sapling", 3, 4470);
+        register("minecraft:sapling", 4, 4471);
+        register("minecraft:sapling", 5, 4472);
+        register("minecraft:tallgrass", 2, 4473);
+        register("minecraft:yellow_flower", 0, 4474);
+        register("minecraft:red_flower", 0, 4475);
+        register("minecraft:red_flower", 1, 4476);
+        register("minecraft:red_flower", 2, 4477);
+        register("minecraft:red_flower", 3, 4478);
+        register("minecraft:red_flower", 4, 4479);
+        register("minecraft:red_flower", 5, 4480);
+        register("minecraft:red_flower", 6, 4481);
+        register("minecraft:red_flower", 7, 4482);
+        register("minecraft:red_flower", 8, 4483);
+        register("minecraft:red_mushroom", 0, 4484);
+        register("minecraft:brown_mushroom", 0, 4485);
+        register("minecraft:deadbush", 0, 4486);
+        register("minecraft:cactus", 0, 4487);
+
+    }
+
+    public static void register(String identifier, int blockData, int newId) {
+        flowers.put(new Pair<>(identifier, blockData), newId);
+    }
+
+    @Override
+    public int transform(UserConnection user, CompoundTag tag) {
+        String item = (String) tag.get("Item").getValue();
+        int data = (int) tag.get("Data").getValue();
+
+        Pair<String, Integer> pair = new Pair<>(item, data);
+
+        if (flowers.containsKey(pair)) {
+            return flowers.get(pair);
+        } else {
+            System.out.println("Could not find flowerpot content " + item + " for " + tag);
+        }
+
+        return -1;
+    }
+}

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/storage/BlockStorage.java

@@ -0,0 +1,79 @@
+package us.myles.ViaVersion.protocols.protocolsnapshotto1_12_2.storage;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import us.myles.ViaVersion.api.data.StoredObject;
+import us.myles.ViaVersion.api.data.UserConnection;
+import us.myles.ViaVersion.api.minecraft.Position;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+public class BlockStorage extends StoredObject {
+    // This BlockStorage is very exclusive (;
+    private static final List<Integer> whitelist = new CopyOnWriteArrayList<>();
+
+    static {
+        // Flower pots
+        whitelist.add(4466);
+
+        // Add those red beds
+        for (int i = 0; i < 16; i++)
+            whitelist.add(896 + i);
+
+        // Add the white banners
+        for (int i = 0; i < 20; i++)
+            whitelist.add(5377 + i);
+
+        // Add the whhite wall banners
+        for (int i = 0; i < 4; i++) {
+            whitelist.add(5633 + i);
+        }
+    }
+
+    private Map<Position, ReplacementData> blocks = new ConcurrentHashMap<>();
+
+    public BlockStorage(UserConnection user) {
+        super(user);
+    }
+
+    public static void main(String[] args) {
+        new BlockStorage(null);
+    }
+
+    public void store(Position position, int block) {
+        store(position, block, -1);
+    }
+
+    public void store(Position position, int block, int replacementId) {
+        if (!whitelist.contains(block))
+            return;
+
+        blocks.put(position, new ReplacementData(block, replacementId));
+    }
+
+    public boolean isWelcome(int block) {
+        return whitelist.contains(block);
+    }
+
+    public boolean contains(Position position) {
+        return blocks.containsKey(position);
+    }
+
+    public ReplacementData get(Position position) {
+        return blocks.get(position);
+    }
+
+    public ReplacementData remove(Position position) {
+        return blocks.remove(position);
+    }
+
+    @Data
+    @AllArgsConstructor
+    public class ReplacementData {
+        private int original;
+        private int replacement;
+    }
+}

common/src/main/resources/assets/viaversion/data/mapping-1.12.json

@@ -894,22 +894,22 @@
     "2208": "minecraft:beacon",
     "2224": "minecraft:cobblestone_wall[east=false,north=false,south=false,up=false,west=false]",
     "2225": "minecraft:mossy_cobblestone_wall[east=false,north=false,south=false,up=false,west=false]",
-    "2240": "minecraft:potted_cactus",
+    "2240": "minecraft:flower_pot",
-    "2241": "minecraft:potted_cactus",
+    "2241": "minecraft:flower_pot",
-    "2242": "minecraft:potted_cactus",
+    "2242": "minecraft:flower_pot",
-    "2243": "minecraft:potted_cactus",
+    "2243": "minecraft:flower_pot",
-    "2244": "minecraft:potted_cactus",
+    "2244": "minecraft:flower_pot",
-    "2245": "minecraft:potted_cactus",
+    "2245": "minecraft:flower_pot",
-    "2246": "minecraft:potted_cactus",
+    "2246": "minecraft:flower_pot",
-    "2247": "minecraft:potted_cactus",
+    "2247": "minecraft:flower_pot",
-    "2248": "minecraft:potted_cactus",
+    "2248": "minecraft:flower_pot",
-    "2249": "minecraft:potted_cactus",
+    "2249": "minecraft:flower_pot",
-    "2250": "minecraft:potted_cactus",
+    "2250": "minecraft:flower_pot",
-    "2251": "minecraft:potted_cactus",
+    "2251": "minecraft:flower_pot",
-    "2252": "minecraft:potted_cactus",
+    "2252": "minecraft:flower_pot",
-    "2253": "minecraft:potted_cactus",
+    "2253": "minecraft:flower_pot",
-    "2254": "minecraft:potted_cactus",
+    "2254": "minecraft:flower_pot",
-    "2255": "minecraft:potted_cactus",
+    "2255": "minecraft:flower_pot",
     "2256": "minecraft:carrots[age=0]",
     "2257": "minecraft:carrots[age=1]",
     "2258": "minecraft:carrots[age=2]",
@@ -2170,6 +2170,22 @@
     "6720": "minecraft:lead",
     "6736": "minecraft:name_tag",
     "6752": "minecraft:command_block_minecart",
+    "6800": "minecraft:black_banner",
+    "6801": "minecraft:red_banner",
+    "6802": "minecraft:green_banner",
+    "6803": "minecraft:brown_banner",
+    "6804": "minecraft:blue_banner",
+    "6805": "minecraft:purple_banner",
+    "6806": "minecraft:cyan_banner",
+    "6807": "minecraft:light_gray_banner",
+    "6808": "minecraft:gray_banner",
+    "6809": "minecraft:pink_banner",
+    "6810": "minecraft:lime_banner",
+    "6811": "minecraft:yellow_banner",
+    "6812": "minecraft:light_blue_banner",
+    "6813": "minecraft:magenta_banner",
+    "6814": "minecraft:orange_banner",
+    "6815": "minecraft:white_banner",
     "36096": "minecraft:music_disc_13",
     "36112": "minecraft:music_disc_cat",
     "36128": "minecraft:music_disc_blocks",