Allow "post processing" of chunks (#658)

* begin allowing "post processing" of chunks
 - restores legacy capability to continue saving edits in the background after sending the chunks
 - speeds up the edit clientside
 - nail in the coffin of the terrible and staticly coded coreedit
 - We should totally make IronGolem work so Core* is no longer used by anyone

* begin allowing background history saving

* Handle post processors in queues properly

* Use futures for postprocessing so we're not waiting for them needlessly

* better use of closed boolean

* Reword

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_15_2/BukkitAdapter_1_15_2.java

@@ -14,6 +14,8 @@ import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockTypesCache;
 import io.papermc.lib.PaperLib;
 import net.jpountz.util.UnsafeUtils;
+import net.minecraft.server.v1_15_R1.BiomeBase;
+import net.minecraft.server.v1_15_R1.BiomeStorage;
 import net.minecraft.server.v1_15_R1.Block;
 import net.minecraft.server.v1_15_R1.Chunk;
 import net.minecraft.server.v1_15_R1.ChunkCoordIntPair;
@@ -61,6 +63,8 @@ public final class BukkitAdapter_1_15_2 extends NMSAdapter {
     private final static Field fieldDirtyCount;
     private final static Field fieldDirtyBits;
 
+    private static final Field fieldBiomeArray;
+
     private final static MethodHandle methodGetVisibleChunk;
 
     public final static MethodHandle methodSetLightNibbleArray;
@@ -91,6 +95,9 @@ public final class BukkitAdapter_1_15_2 extends NMSAdapter {
             fieldDirtyBits = PlayerChunk.class.getDeclaredField("r");
             fieldDirtyBits.setAccessible(true);
 
+            fieldBiomeArray = BiomeStorage.class.getDeclaredField("h");
+            fieldBiomeArray.setAccessible(true);
+
             Method declaredGetVisibleChunk = PlayerChunkMap.class.getDeclaredMethod("getVisibleChunk", long.class);
             declaredGetVisibleChunk.setAccessible(true);
             methodGetVisibleChunk = MethodHandles.lookup().unreflect(declaredGetVisibleChunk);
@@ -307,4 +314,13 @@ public final class BukkitAdapter_1_15_2 extends NMSAdapter {
         fieldTickingBlockCount.setShort(section, (short) tickingBlockCount);
         fieldNonEmptyBlockCount.setShort(section, (short) nonEmptyBlockCount);
     }
+
+    public static BiomeBase[] getBiomeArray(BiomeStorage storage) {
+        try {
+            return (BiomeBase[]) fieldBiomeArray.get(storage);
+        } catch (IllegalAccessException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
 }

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_15_2/BukkitGetBlocks_1_15_2.java

@@ -2,6 +2,7 @@ package com.boydti.fawe.bukkit.adapter.mc1_15_2;
 
 import com.boydti.fawe.Fawe;
 import com.boydti.fawe.FaweCache;
+import com.boydti.fawe.beta.IChunkGet;
 import com.boydti.fawe.beta.IChunkSet;
 import com.boydti.fawe.beta.implementation.blocks.CharBlocks;
 import com.boydti.fawe.beta.implementation.blocks.CharGetBlocks;
@@ -86,6 +87,8 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
     public int X, Z;
     public NibbleArray[] blockLight = new NibbleArray[16];
     public NibbleArray[] skyLight = new NibbleArray[16];
+    private boolean createCopy = false;
+    private BukkitGetBlocks_1_15_2_Copy copy = null;
 
     public BukkitGetBlocks_1_15_2(World world, int X, int Z) {
         this(((CraftWorld) world).getHandle(), X, Z);
@@ -97,6 +100,21 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
         this.Z = Z;
     }
 
+    @Override
+    public void setCreateCopy(boolean createCopy) {
+        this.createCopy = createCopy;
+    }
+
+    @Override
+    public boolean isCreateCopy() {
+        return createCopy;
+    }
+
+    @Override
+    public IChunkGet getCopy() {
+        return copy;
+    }
+
     public int getX() {
         return X;
     }
@@ -292,6 +310,7 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
 
     @Override
     public <T extends Future<T>> T call(IChunkSet set, Runnable finalizer) {
+        copy = createCopy ? new BukkitGetBlocks_1_15_2_Copy(world, getX(), getZ()) : null;
         try {
             WorldServer nmsWorld = world;
             Chunk nmsChunk = ensureLoaded(nmsWorld, X, Z);
@@ -316,6 +335,9 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
                         if (ordinal != 0) {
                             TileEntity tile = entry.getValue();
                             nmsChunk.removeTileEntity(tile.getPosition());
+                            if (createCopy) {
+                                copy.storeTile(tile);
+                            }
                         }
                     }
                 }
@@ -329,6 +351,9 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
                     if (!set.hasSection(layer)){
                         continue;
                     }
+                    if (createCopy) {
+                        copy.storeSection(layer);
+                    }
 
                     bitMask |= 1 << layer;
 
@@ -384,6 +409,9 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
                 if (biomes != null) {
                     // set biomes
                     BiomeStorage currentBiomes = nmsChunk.getBiomeIndex();
+                    if (createCopy) {
+                        copy.storeBiomes(currentBiomes);
+                    }
                     for (int z = 0, i = 0; z < 16; z++) {
                         for (int x = 0; x < 16; x++, i++) {
                             final BiomeType biome = biomes[i];
@@ -446,6 +474,9 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
                                 while (iter.hasNext()) {
                                     final Entity entity = iter.next();
                                     if (entityRemoves.contains(entity.getUniqueID())) {
+                                        if (createCopy) {
+                                            copy.storeEntity(entity);
+                                        }
                                         iter.remove();
                                         removeEntity(entity);
                                     }

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_15_2/BukkitGetBlocks_1_15_2_Copy.java

@@ -0,0 +1,129 @@
+package com.boydti.fawe.bukkit.adapter.mc1_15_2;
+
+
+import com.boydti.fawe.FaweCache;
+import com.boydti.fawe.bukkit.adapter.mc1_15_2.nbt.LazyCompoundTag_1_15_2;
+import com.google.common.base.Suppliers;
+import com.sk89q.jnbt.CompoundTag;
+import com.sk89q.worldedit.bukkit.BukkitAdapter;
+import com.sk89q.worldedit.bukkit.WorldEditPlugin;
+import com.sk89q.worldedit.bukkit.adapter.BukkitImplAdapter;
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.world.biome.BiomeType;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockState;
+import com.sk89q.worldedit.world.block.BlockTypesCache;
+import net.minecraft.server.v1_15_R1.BiomeBase;
+import net.minecraft.server.v1_15_R1.BiomeStorage;
+import net.minecraft.server.v1_15_R1.Entity;
+import net.minecraft.server.v1_15_R1.NBTTagCompound;
+import net.minecraft.server.v1_15_R1.TileEntity;
+import net.minecraft.server.v1_15_R1.WorldServer;
+import org.bukkit.craftbukkit.v1_15_R1.block.CraftBlock;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+public class BukkitGetBlocks_1_15_2_Copy extends BukkitGetBlocks_1_15_2 {
+
+    private final Map<BlockVector3, CompoundTag> tiles = new HashMap<>();
+    private final Set<CompoundTag> entities = new HashSet<>();
+    private BiomeStorage biomeStorage;
+    private final char[][] blocks = new char[16][4096];
+
+    protected BukkitGetBlocks_1_15_2_Copy(WorldServer world, int X, int Z) {
+        super(world, X, Z);
+    }
+
+    protected void storeTile(TileEntity tile) {
+        tiles.put(BlockVector3.at(tile.getPosition().getX(), tile.getPosition().getY(), tile.getPosition().getZ()),
+            new LazyCompoundTag_1_15_2(Suppliers.memoize(() -> tile.save(new NBTTagCompound()))));
+    }
+
+    @Override
+    public Map<BlockVector3, CompoundTag> getTiles() {
+        return tiles;
+    }
+
+    @Override
+    @Nullable
+    public CompoundTag getTile(int x, int y, int z) {
+        return tiles.get(BlockVector3.at(x, y, z));
+    }
+
+    protected void storeEntity(Entity entity) {
+        BukkitImplAdapter adapter = WorldEditPlugin.getInstance().getBukkitImplAdapter();
+        NBTTagCompound tag = new NBTTagCompound();
+        entities.add((CompoundTag) adapter.toNative(entity.save(tag)));
+    }
+
+    @Override
+    public Set<CompoundTag> getEntities() {
+        return this.entities;
+    }
+
+    @Override
+    public CompoundTag getEntity(UUID uuid) {
+        for (CompoundTag tag : entities) {
+            UUID tagUUID;
+            if (tag.containsKey("UUID")) {
+                int[] arr = tag.getIntArray("UUID");
+                tagUUID = new UUID((long) arr[0] << 32 | (arr[1] & 0xFFFFFFFFL), (long) arr[2] << 32 | (arr[3] & 0xFFFFFFFFL));
+            } else if (tag.containsKey("UUIDMost")) {
+                tagUUID = new UUID(tag.getLong("UUIDMost"), tag.getLong("UUIDLeast"));
+            } else if (tag.containsKey("PersistentIDMSB")) {
+                tagUUID = new UUID(tag.getLong("PersistentIDMSB"), tag.getLong("PersistentIDLSB"));
+            } else {
+                return null;
+            }
+            if (uuid.equals(tagUUID)) {
+                return tag;
+            }
+        }
+        return null;
+    }
+
+    protected void storeBiomes(BiomeStorage biomeStorage) {
+        this.biomeStorage = new BiomeStorage(BukkitAdapter_1_15_2.getBiomeArray(biomeStorage).clone());
+    }
+
+    @Override
+    public BiomeType getBiomeType(int x, int y, int z) {
+        BiomeBase base = null;
+        if (y == -1) {
+            for (y = 0; y < FaweCache.IMP.WORLD_HEIGHT; y++) {
+                base = biomeStorage.getBiome(x >> 2, y >> 2, z >> 2);
+                if (base != null) break;
+            }
+        } else {
+            base = biomeStorage.getBiome(x >> 2, y >> 2, z >> 2);
+        }
+        return base != null ? BukkitAdapter.adapt(CraftBlock.biomeBaseToBiome(base)) : null;
+    }
+
+    protected void storeSection(int layer) {
+        update(layer, blocks[layer]);
+    }
+
+    @Override
+    public BaseBlock getFullBlock(int x, int y, int z) {
+        BlockState state = BlockTypesCache.states[get(x, y, z)];
+        return state.toBaseBlock(this, x, y, z);
+    }
+
+    @Override
+    public BlockState getBlock(int x, int y, int z) {
+        return BlockTypesCache.states[get(x, y, z)];
+    }
+
+    @Override
+    public char get(int x, int y, int z) {
+        final int layer = y >> 4;
+        final int index = (y & 15) << 8 | z << 4 | x;
+        return blocks[layer][index];
+    }
+}

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_1/BukkitAdapter_1_16_1.java

@@ -47,6 +47,8 @@ public final class BukkitAdapter_1_16_1 extends NMSAdapter {
     private final static Field fieldDirtyCount;
     private final static Field fieldDirtyBits;
 
+    private static final Field fieldBiomeArray;
+
     private final static MethodHandle methodGetVisibleChunk;
 
     private static final int CHUNKSECTION_BASE;
@@ -78,6 +80,9 @@ public final class BukkitAdapter_1_16_1 extends NMSAdapter {
             fieldDirtyBits = PlayerChunk.class.getDeclaredField("r");
             fieldDirtyBits.setAccessible(true);
 
+            fieldBiomeArray = BiomeStorage.class.getDeclaredField("h");
+            fieldBiomeArray.setAccessible(true);
+
             Method declaredGetVisibleChunk = PlayerChunkMap.class.getDeclaredMethod("getVisibleChunk", long.class);
             declaredGetVisibleChunk.setAccessible(true);
             methodGetVisibleChunk = MethodHandles.lookup().unreflect(declaredGetVisibleChunk);
@@ -291,4 +296,13 @@ public final class BukkitAdapter_1_16_1 extends NMSAdapter {
         fieldTickingBlockCount.setShort(section, (short) tickingBlockCount);
         fieldNonEmptyBlockCount.setShort(section, (short) nonEmptyBlockCount);
     }
+
+    public static BiomeBase[] getBiomeArray(BiomeStorage storage) {
+        try {
+            return (BiomeBase[]) fieldBiomeArray.get(storage);
+        } catch (IllegalAccessException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
 }

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_1/BukkitGetBlocks_1_16_1.java

@@ -2,6 +2,7 @@ package com.boydti.fawe.bukkit.adapter.mc1_16_1;
 
 import com.boydti.fawe.Fawe;
 import com.boydti.fawe.FaweCache;
+import com.boydti.fawe.beta.IChunkGet;
 import com.boydti.fawe.beta.IChunkSet;
 import com.boydti.fawe.beta.implementation.blocks.CharBlocks;
 import com.boydti.fawe.beta.implementation.blocks.CharGetBlocks;
@@ -11,7 +12,6 @@ import com.boydti.fawe.bukkit.adapter.DelegateLock;
 import com.boydti.fawe.bukkit.adapter.mc1_16_1.nbt.LazyCompoundTag_1_16_1;
 import com.boydti.fawe.config.Settings;
 import com.boydti.fawe.object.collection.AdaptedMap;
-import com.boydti.fawe.object.collection.BitArray;
 import com.boydti.fawe.object.collection.BitArrayUnstretched;
 import com.google.common.base.Suppliers;
 import com.google.common.collect.Iterables;
@@ -55,6 +55,8 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
     public int X, Z;
     public NibbleArray[] blockLight = new NibbleArray[16];
     public NibbleArray[] skyLight = new NibbleArray[16];
+    private boolean createCopy = false;
+    private BukkitGetBlocks_1_16_1_Copy copy = null;
 
     public BukkitGetBlocks_1_16_1(World world, int X, int Z) {
         this(((CraftWorld) world).getHandle(), X, Z);
@@ -66,6 +68,21 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
         this.Z = Z;
     }
 
+    @Override
+    public void setCreateCopy(boolean createCopy) {
+        this.createCopy = createCopy;
+    }
+
+    @Override
+    public boolean isCreateCopy() {
+        return createCopy;
+    }
+
+    @Override
+    public IChunkGet getCopy() {
+        return copy;
+    }
+
     public int getX() {
         return X;
     }
@@ -259,6 +276,7 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
 
     @Override
     public <T extends Future<T>> T call(IChunkSet set, Runnable finalizer) {
+        copy = createCopy ? new BukkitGetBlocks_1_16_1_Copy(world, getX(), getZ()) : null;
         try {
             WorldServer nmsWorld = world;
             Chunk nmsChunk = ensureLoaded(nmsWorld, X, Z);
@@ -283,6 +301,9 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
                         if (ordinal != 0) {
                             TileEntity tile = entry.getValue();
                             nmsChunk.removeTileEntity(tile.getPosition());
+                            if (createCopy) {
+                                copy.storeTile(tile);
+                            }
                         }
                     }
                 }
@@ -296,6 +317,9 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
                     if (!set.hasSection(layer)){
                         continue;
                     }
+                    if (createCopy) {
+                        copy.storeSection(layer);
+                    }
 
                     bitMask |= 1 << layer;
 
@@ -353,6 +377,9 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
                 if (biomes != null) {
                     // set biomes
                     BiomeStorage currentBiomes = nmsChunk.getBiomeIndex();
+                    if (createCopy) {
+                        copy.storeBiomes(currentBiomes);
+                    }
                     for (int z = 0, i = 0; z < 16; z++) {
                         for (int x = 0; x < 16; x++, i++) {
                             final BiomeType biome = biomes[i];
@@ -415,6 +442,9 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
                                 while (iter.hasNext()) {
                                     final Entity entity = iter.next();
                                     if (entityRemoves.contains(entity.getUniqueID())) {
+                                        if (createCopy) {
+                                            copy.storeEntity(entity);
+                                        }
                                         iter.remove();
                                         removeEntity(entity);
                                     }

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_1/BukkitGetBlocks_1_16_1_Copy.java

@@ -0,0 +1,130 @@
+package com.boydti.fawe.bukkit.adapter.mc1_16_1;
+
+
+import com.boydti.fawe.FaweCache;
+import com.boydti.fawe.bukkit.adapter.mc1_16_1.nbt.LazyCompoundTag_1_16_1;
+import com.google.common.base.Suppliers;
+import com.sk89q.jnbt.CompoundTag;
+import com.sk89q.worldedit.bukkit.BukkitAdapter;
+import com.sk89q.worldedit.bukkit.WorldEditPlugin;
+import com.sk89q.worldedit.bukkit.adapter.BukkitImplAdapter;
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.world.biome.BiomeType;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockState;
+import com.sk89q.worldedit.world.block.BlockTypesCache;
+import net.minecraft.server.v1_16_R1.BiomeBase;
+import net.minecraft.server.v1_16_R1.BiomeStorage;
+import net.minecraft.server.v1_16_R1.Entity;
+import net.minecraft.server.v1_16_R1.IRegistry;
+import net.minecraft.server.v1_16_R1.NBTTagCompound;
+import net.minecraft.server.v1_16_R1.TileEntity;
+import net.minecraft.server.v1_16_R1.WorldServer;
+import org.bukkit.craftbukkit.v1_16_R1.block.CraftBlock;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+public class BukkitGetBlocks_1_16_1_Copy extends BukkitGetBlocks_1_16_1 {
+
+    private final Map<BlockVector3, CompoundTag> tiles = new HashMap<>();
+    private final Set<CompoundTag> entities = new HashSet<>();
+    private BiomeStorage biomeStorage;
+    private final char[][] blocks = new char[16][4096];
+
+    protected BukkitGetBlocks_1_16_1_Copy(WorldServer world, int X, int Z) {
+        super(world, X, Z);
+    }
+
+    protected void storeTile(TileEntity tile) {
+        tiles.put(BlockVector3.at(tile.getPosition().getX(), tile.getPosition().getY(), tile.getPosition().getZ()),
+            new LazyCompoundTag_1_16_1(Suppliers.memoize(() -> tile.save(new NBTTagCompound()))));
+    }
+
+    @Override
+    public Map<BlockVector3, CompoundTag> getTiles() {
+        return tiles;
+    }
+
+    @Override
+    @Nullable
+    public CompoundTag getTile(int x, int y, int z) {
+        return tiles.get(BlockVector3.at(x, y, z));
+    }
+
+    protected void storeEntity(Entity entity) {
+        BukkitImplAdapter adapter = WorldEditPlugin.getInstance().getBukkitImplAdapter();
+        NBTTagCompound tag = new NBTTagCompound();
+        entities.add((CompoundTag) adapter.toNative(entity.save(tag)));
+    }
+
+    @Override
+    public Set<CompoundTag> getEntities() {
+        return this.entities;
+    }
+
+    @Override
+    public CompoundTag getEntity(UUID uuid) {
+        for (CompoundTag tag : entities) {
+            UUID tagUUID;
+            if (tag.containsKey("UUID")) {
+                int[] arr = tag.getIntArray("UUID");
+                tagUUID = new UUID((long) arr[0] << 32 | (arr[1] & 0xFFFFFFFFL), (long) arr[2] << 32 | (arr[3] & 0xFFFFFFFFL));
+            } else if (tag.containsKey("UUIDMost")) {
+                tagUUID = new UUID(tag.getLong("UUIDMost"), tag.getLong("UUIDLeast"));
+            } else if (tag.containsKey("PersistentIDMSB")) {
+                tagUUID = new UUID(tag.getLong("PersistentIDMSB"), tag.getLong("PersistentIDLSB"));
+            } else {
+                return null;
+            }
+            if (uuid.equals(tagUUID)) {
+                return tag;
+            }
+        }
+        return null;
+    }
+
+    protected void storeBiomes(BiomeStorage biomeStorage) {
+        this.biomeStorage = new BiomeStorage(BukkitAdapter_1_16_1.getBiomeArray(biomeStorage).clone());
+    }
+
+    @Override
+    public BiomeType getBiomeType(int x, int y, int z) {
+        BiomeBase base = null;
+        if (y == -1) {
+            for (y = 0; y < FaweCache.IMP.WORLD_HEIGHT; y++) {
+                base = biomeStorage.getBiome(x >> 2, y >> 2, z >> 2);
+                if (base != null) break;
+            }
+        } else {
+            base = biomeStorage.getBiome(x >> 2, y >> 2, z >> 2);
+        }
+        return base != null ? BukkitAdapter.adapt(CraftBlock.biomeBaseToBiome(base)) : null;
+    }
+
+    protected void storeSection(int layer) {
+        update(layer, blocks[layer]);
+    }
+
+    @Override
+    public BaseBlock getFullBlock(int x, int y, int z) {
+        BlockState state = BlockTypesCache.states[get(x, y, z)];
+        return state.toBaseBlock(this, x, y, z);
+    }
+
+    @Override
+    public BlockState getBlock(int x, int y, int z) {
+        return BlockTypesCache.states[get(x, y, z)];
+    }
+
+    @Override
+    public char get(int x, int y, int z) {
+        final int layer = y >> 4;
+        final int index = (y & 15) << 8 | z << 4 | x;
+        return blocks[layer][index];
+    }
+}

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_2/BukkitAdapter_1_16_2.java

@@ -15,6 +15,8 @@ import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockTypesCache;
 import io.papermc.lib.PaperLib;
 import net.jpountz.util.UnsafeUtils;
+import net.minecraft.server.v1_16_R2.BiomeBase;
+import net.minecraft.server.v1_16_R2.BiomeStorage;
 import net.minecraft.server.v1_16_R2.Block;
 import net.minecraft.server.v1_16_R2.Chunk;
 import net.minecraft.server.v1_16_R2.ChunkCoordIntPair;
@@ -64,6 +66,8 @@ public final class BukkitAdapter_1_16_2 extends NMSAdapter {
     private static final Field fieldDirty;
     private static final Field fieldDirtyBlocks;
 
+    private static final Field fieldBiomeArray;
+
     private static final MethodHandle methodGetVisibleChunk;
 
     private static final int CHUNKSECTION_BASE;
@@ -95,6 +99,9 @@ public final class BukkitAdapter_1_16_2 extends NMSAdapter {
             fieldDirtyBlocks = PlayerChunk.class.getDeclaredField("dirtyBlocks");
             fieldDirtyBlocks.setAccessible(true);
 
+            fieldBiomeArray = BiomeStorage.class.getDeclaredField("h");
+            fieldBiomeArray.setAccessible(true);
+
             Method declaredGetVisibleChunk = PlayerChunkMap.class.getDeclaredMethod("getVisibleChunk", long.class);
             declaredGetVisibleChunk.setAccessible(true);
             methodGetVisibleChunk = MethodHandles.lookup().unreflect(declaredGetVisibleChunk);
@@ -286,7 +293,7 @@ public final class BukkitAdapter_1_16_2 extends NMSAdapter {
                         .setType(pos.getBlockX(), pos.getBlockY(), pos.getBlockZ(),
                             Block.getByCombinedId(ordinal)));
                 }
-            } catch (final IllegalAccessException | NoSuchFieldException e) {
+            } catch (final IllegalAccessException e) {
                 throw new RuntimeException(e);
             }
 
@@ -301,9 +308,18 @@ public final class BukkitAdapter_1_16_2 extends NMSAdapter {
         return new ChunkSection(layer << 4);
     }
 
-    public static void setCount(final int tickingBlockCount, final int nonEmptyBlockCount, final ChunkSection section) throws NoSuchFieldException, IllegalAccessException {
+    public static void setCount(final int tickingBlockCount, final int nonEmptyBlockCount, final ChunkSection section) throws IllegalAccessException {
         fieldFluidCount.setShort(section, (short) 0); // TODO FIXME
         fieldTickingBlockCount.setShort(section, (short) tickingBlockCount);
         fieldNonEmptyBlockCount.setShort(section, (short) nonEmptyBlockCount);
     }
+
+    public static BiomeBase[] getBiomeArray(BiomeStorage storage) {
+        try {
+            return (BiomeBase[]) fieldBiomeArray.get(storage);
+        } catch (IllegalAccessException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
 }

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_2/BukkitGetBlocks_1_16_2.java

@@ -2,6 +2,7 @@ package com.boydti.fawe.bukkit.adapter.mc1_16_2;
 
 import com.boydti.fawe.Fawe;
 import com.boydti.fawe.FaweCache;
+import com.boydti.fawe.beta.IChunkGet;
 import com.boydti.fawe.beta.IChunkSet;
 import com.boydti.fawe.beta.implementation.blocks.CharBlocks;
 import com.boydti.fawe.beta.implementation.blocks.CharGetBlocks;
@@ -11,7 +12,6 @@ import com.boydti.fawe.bukkit.adapter.DelegateLock;
 import com.boydti.fawe.bukkit.adapter.mc1_16_2.nbt.LazyCompoundTag_1_16_2;
 import com.boydti.fawe.config.Settings;
 import com.boydti.fawe.object.collection.AdaptedMap;
-import com.boydti.fawe.object.collection.BitArray;
 import com.boydti.fawe.object.collection.BitArrayUnstretched;
 import com.google.common.base.Suppliers;
 import com.google.common.collect.Iterables;
@@ -55,6 +55,8 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
     public int X, Z;
     public NibbleArray[] blockLight = new NibbleArray[16];
     public NibbleArray[] skyLight = new NibbleArray[16];
+    private boolean createCopy = false;
+    private BukkitGetBlocks_1_16_2_Copy copy = null;
 
     public BukkitGetBlocks_1_16_2(World world, int X, int Z) {
         this(((CraftWorld) world).getHandle(), X, Z);
@@ -66,6 +68,21 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
         this.Z = Z;
     }
 
+    @Override
+    public void setCreateCopy(boolean createCopy) {
+        this.createCopy = createCopy;
+    }
+
+    @Override
+    public boolean isCreateCopy() {
+        return createCopy;
+    }
+
+    @Override
+    public IChunkGet getCopy() {
+        return copy;
+    }
+
     public int getX() {
         return X;
     }
@@ -107,7 +124,8 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
         return AdaptedMap.immutable(nmsTiles, posNms2We, nmsTile2We);
     }
 
-    @Override public int getSkyLight(int x, int y, int z) {
+    @Override
+    public int getSkyLight(int x, int y, int z) {
         int layer = y >> 4;
         if (skyLight[layer] == null) {
             SectionPosition sectionPosition = SectionPosition.a(nmsChunk.getPos(), layer);
@@ -126,7 +144,8 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
         return skyLight[layer].a(SectionPosition.b(BlockPosition.b(l)), SectionPosition.b(BlockPosition.c(l)), SectionPosition.b(BlockPosition.d(l)));
     }
 
-    @Override public int getEmmittedLight(int x, int y, int z) {
+    @Override
+    public int getEmmittedLight(int x, int y, int z) {
         int layer = y >> 4;
         if (blockLight[layer] == null) {
             SectionPosition sectionPosition = SectionPosition.a(nmsChunk.getPos(), layer);
@@ -145,7 +164,8 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
         return blockLight[layer].a(SectionPosition.b(BlockPosition.b(l)), SectionPosition.b(BlockPosition.c(l)), SectionPosition.b(BlockPosition.d(l)));
     }
 
-    @Override public int[] getHeightMap(HeightMapType type) {
+    @Override
+    public int[] getHeightMap(HeightMapType type) {
         long[] longArray = getChunk().heightMap.get(HeightMap.Type.valueOf(type.name())).a();
         BitArrayUnstretched bitArray = new BitArrayUnstretched(9, 256, longArray);
         return bitArray.toRaw(new int[256]);
@@ -259,6 +279,7 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
 
     @Override
     public <T extends Future<T>> T call(IChunkSet set, Runnable finalizer) {
+        copy = createCopy ? new BukkitGetBlocks_1_16_2_Copy(world, getX(), getZ()) : null;
         try {
             WorldServer nmsWorld = world;
             Chunk nmsChunk = ensureLoaded(nmsWorld, X, Z);
@@ -283,6 +304,9 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
                         if (ordinal != 0) {
                             TileEntity tile = entry.getValue();
                             nmsChunk.removeTileEntity(tile.getPosition());
+                            if (createCopy) {
+                                copy.storeTile(tile);
+                            }
                         }
                     }
                 }
@@ -296,6 +320,9 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
                     if (!set.hasSection(layer)){
                         continue;
                     }
+                    if (createCopy) {
+                        copy.storeSection(layer);
+                    }
 
                     bitMask |= 1 << layer;
 
@@ -353,6 +380,9 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
                 if (biomes != null) {
                     // set biomes
                     BiomeStorage currentBiomes = nmsChunk.getBiomeIndex();
+                    if (createCopy) {
+                        copy.storeBiomes(currentBiomes);
+                    }
                     for (int z = 0, i = 0; z < 16; z++) {
                         for (int x = 0; x < 16; x++, i++) {
                             final BiomeType biome = biomes[i];
@@ -415,6 +445,9 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
                                 while (iter.hasNext()) {
                                     final Entity entity = iter.next();
                                     if (entityRemoves.contains(entity.getUniqueID())) {
+                                        if (createCopy) {
+                                            copy.storeEntity(entity);
+                                        }
                                         iter.remove();
                                         removeEntity(entity);
                                     }

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_2/BukkitGetBlocks_1_16_2_Copy.java

@@ -0,0 +1,130 @@
+package com.boydti.fawe.bukkit.adapter.mc1_16_2;
+
+
+import com.boydti.fawe.FaweCache;
+import com.boydti.fawe.bukkit.adapter.mc1_16_2.nbt.LazyCompoundTag_1_16_2;
+import com.google.common.base.Suppliers;
+import com.sk89q.jnbt.CompoundTag;
+import com.sk89q.worldedit.bukkit.BukkitAdapter;
+import com.sk89q.worldedit.bukkit.WorldEditPlugin;
+import com.sk89q.worldedit.bukkit.adapter.BukkitImplAdapter;
+import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.world.biome.BiomeType;
+import com.sk89q.worldedit.world.block.BaseBlock;
+import com.sk89q.worldedit.world.block.BlockState;
+import com.sk89q.worldedit.world.block.BlockTypesCache;
+import net.minecraft.server.v1_16_R2.BiomeBase;
+import net.minecraft.server.v1_16_R2.BiomeStorage;
+import net.minecraft.server.v1_16_R2.Entity;
+import net.minecraft.server.v1_16_R2.IRegistry;
+import net.minecraft.server.v1_16_R2.NBTTagCompound;
+import net.minecraft.server.v1_16_R2.TileEntity;
+import net.minecraft.server.v1_16_R2.WorldServer;
+import org.bukkit.craftbukkit.v1_16_R2.block.CraftBlock;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+public class BukkitGetBlocks_1_16_2_Copy extends BukkitGetBlocks_1_16_2 {
+
+    private final Map<BlockVector3, CompoundTag> tiles = new HashMap<>();
+    private final Set<CompoundTag> entities = new HashSet<>();
+    private BiomeStorage biomeStorage;
+    private final char[][] blocks = new char[16][4096];
+
+    protected BukkitGetBlocks_1_16_2_Copy(WorldServer world, int X, int Z) {
+        super(world, X, Z);
+    }
+
+    protected void storeTile(TileEntity tile) {
+        tiles.put(BlockVector3.at(tile.getPosition().getX(), tile.getPosition().getY(), tile.getPosition().getZ()),
+            new LazyCompoundTag_1_16_2(Suppliers.memoize(() -> tile.save(new NBTTagCompound()))));
+    }
+
+    @Override
+    public Map<BlockVector3, CompoundTag> getTiles() {
+        return tiles;
+    }
+
+    @Override
+    @Nullable
+    public CompoundTag getTile(int x, int y, int z) {
+        return tiles.get(BlockVector3.at(x, y, z));
+    }
+
+    protected void storeEntity(Entity entity) {
+        BukkitImplAdapter adapter = WorldEditPlugin.getInstance().getBukkitImplAdapter();
+        NBTTagCompound tag = new NBTTagCompound();
+        entities.add((CompoundTag) adapter.toNative(entity.save(tag)));
+    }
+
+    @Override
+    public Set<CompoundTag> getEntities() {
+        return this.entities;
+    }
+
+    @Override
+    public CompoundTag getEntity(UUID uuid) {
+        for (CompoundTag tag : entities) {
+            UUID tagUUID;
+            if (tag.containsKey("UUID")) {
+                int[] arr = tag.getIntArray("UUID");
+                tagUUID = new UUID((long) arr[0] << 32 | (arr[1] & 0xFFFFFFFFL), (long) arr[2] << 32 | (arr[3] & 0xFFFFFFFFL));
+            } else if (tag.containsKey("UUIDMost")) {
+                tagUUID = new UUID(tag.getLong("UUIDMost"), tag.getLong("UUIDLeast"));
+            } else if (tag.containsKey("PersistentIDMSB")) {
+                tagUUID = new UUID(tag.getLong("PersistentIDMSB"), tag.getLong("PersistentIDLSB"));
+            } else {
+                return null;
+            }
+            if (uuid.equals(tagUUID)) {
+                return tag;
+            }
+        }
+        return null;
+    }
+
+    protected void storeBiomes(BiomeStorage biomeStorage) {
+        this.biomeStorage = new BiomeStorage(biomeStorage.g, BukkitAdapter_1_16_2.getBiomeArray(biomeStorage).clone());
+    }
+
+    @Override
+    public BiomeType getBiomeType(int x, int y, int z) {
+        BiomeBase base = null;
+        if (y == -1) {
+            for (y = 0; y < FaweCache.IMP.WORLD_HEIGHT; y++) {
+                base = biomeStorage.getBiome(x >> 2, y >> 2, z >> 2);
+                if (base != null) break;
+            }
+        } else {
+            base = biomeStorage.getBiome(x >> 2, y >> 2, z >> 2);
+        }
+        return base != null ? BukkitAdapter.adapt(CraftBlock.biomeBaseToBiome(world.r().b(IRegistry.ay), base)) : null;
+    }
+
+    protected void storeSection(int layer) {
+        update(layer, blocks[layer]);
+    }
+
+    @Override
+    public BaseBlock getFullBlock(int x, int y, int z) {
+        BlockState state = BlockTypesCache.states[get(x, y, z)];
+        return state.toBaseBlock(this, x, y, z);
+    }
+
+    @Override
+    public BlockState getBlock(int x, int y, int z) {
+        return BlockTypesCache.states[get(x, y, z)];
+    }
+
+    @Override
+    public char get(int x, int y, int z) {
+        final int layer = y >> 4;
+        final int index = (y & 15) << 8 | z << 4 | x;
+        return blocks[layer][index];
+    }
+}

worldedit-core/src/main/java/com/boydti/fawe/beta/IBatchProcessor.java

@@ -11,6 +11,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.Future;
 import java.util.function.Function;
 
 public interface IBatchProcessor {
@@ -23,6 +24,8 @@ public interface IBatchProcessor {
      */
     IChunkSet processSet(IChunk chunk, IChunkGet get, IChunkSet set);
 
+    Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set);
+
     default boolean processGet(int chunkX, int chunkZ) {
         return true;
     }
@@ -115,6 +118,10 @@ public interface IBatchProcessor {
         return MultiBatchProcessor.of(this, other);
     }
 
+    default IBatchProcessor joinPost(IBatchProcessor other) {
+        return MultiBatchProcessor.of(this, other);
+    }
+
     default void flush() {}
 
     /**

worldedit-core/src/main/java/com/boydti/fawe/beta/IChunkGet.java

@@ -7,6 +7,7 @@ import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BaseBlock;
 import com.sk89q.worldedit.world.block.BlockState;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.UUID;
 import java.util.concurrent.Future;
@@ -46,4 +47,13 @@ public interface IChunkGet extends IBlocks, Trimable, InputExtent, ITileInput {
     <T extends Future<T>> T call(IChunkSet set, Runnable finalize);
 
     CompoundTag getEntity(UUID uuid);
+
+    void setCreateCopy(boolean createCopy);
+
+    boolean isCreateCopy();
+
+    @Nullable
+    default IChunkGet getCopy() {
+        return null;
+    }
 }

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/FallbackChunkGet.java

@@ -98,6 +98,12 @@ public class FallbackChunkGet implements IChunkGet {
         return null;
     }
 
+    @Override public void setCreateCopy(boolean createCopy) {}
+
+    @Override public boolean isCreateCopy() {
+        return false;
+    }
+
     @Override
     public boolean trim(boolean aggressive) {
         return true;

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/NullChunkGet.java

@@ -63,6 +63,12 @@ public final class NullChunkGet implements IChunkGet {
         return null;
     }
 
+    @Override public void setCreateCopy(boolean createCopy) {}
+
+    @Override public boolean isCreateCopy() {
+        return false;
+    }
+
     public boolean trim(boolean aggressive) {
         return true;
     }

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/chunk/ChunkHolder.java

@@ -9,6 +9,7 @@ import com.boydti.fawe.beta.IQueueChunk;
 import com.boydti.fawe.beta.IQueueExtent;
 import com.boydti.fawe.beta.implementation.filter.block.ChunkFilterBlock;
 import com.boydti.fawe.beta.implementation.lighting.HeightMapType;
+import com.boydti.fawe.beta.implementation.processors.EmptyBatchProcessor;
 import com.boydti.fawe.beta.implementation.queue.Pool;
 import com.boydti.fawe.config.Settings;
 import com.sk89q.jnbt.CompoundTag;
@@ -20,11 +21,11 @@ import com.sk89q.worldedit.world.block.BlockState;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
 import org.jetbrains.annotations.Range;
 
+import javax.annotation.Nullable;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.Future;
-import javax.annotation.Nullable;
 
 /**
  * An abstract {@link IChunk} class that implements basic get/set blocks
@@ -47,6 +48,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
     private boolean fastmode;
     private int bitMask = -1; // Allow forceful setting of bitmask (for lighting)
     private boolean isInit = false; // Lighting handles queue differently. It relies on the chunk cache and not doing init.
+    private boolean createCopy = false;
 
     private ChunkHolder() {
         this.delegate = NULL;
@@ -140,6 +142,14 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         return delegate.get(this).getEntity(uuid);
     }
 
+    @Override public void setCreateCopy(boolean createCopy) {
+        this.createCopy = createCopy;
+    }
+
+    @Override public boolean isCreateCopy() {
+        return createCopy;
+    }
+
     private static final IBlockDelegate BOTH = new IBlockDelegate() {
         @Override
         public IChunkGet get(ChunkHolder chunk) {
@@ -778,9 +788,15 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
         if (set != null) {
             IChunkGet get = getOrCreateGet();
             get.trim(false);
+            boolean postProcess = !(getExtent().getPostProcessor() instanceof EmptyBatchProcessor);
+            get.setCreateCopy(postProcess);
             set = getExtent().processSet(this, get, set);
-            if (set != null) {
+            try {
                 return get.call(set, finalize);
+            } finally {
+                if (postProcess) {
+                    getExtent().postProcessSet(this, get.getCopy(), set);
+                }
             }
         }
         return null;

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/chunk/NullChunk.java

@@ -171,6 +171,12 @@ public final class NullChunk implements IQueueChunk {
         return null;
     }
 
+    @Override public void setCreateCopy(boolean createCopy) {}
+
+    @Override public boolean isCreateCopy() {
+        return false;
+    }
+
     @Nullable
     public <T extends Future<T>> T call(@Nullable IChunkSet set, @Nullable Runnable finalize) {
         return null;

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/BatchProcessorHolder.java

@@ -5,19 +5,32 @@ import com.boydti.fawe.beta.IChunk;
 import com.boydti.fawe.beta.IChunkGet;
 import com.boydti.fawe.beta.IChunkSet;
 
+import java.util.concurrent.Future;
+
 public class BatchProcessorHolder implements IBatchProcessorHolder {
     private IBatchProcessor processor = EmptyBatchProcessor.getInstance();
+    private IBatchProcessor postProcessor = EmptyBatchProcessor.getInstance();
 
     @Override
     public IBatchProcessor getProcessor() {
         return processor;
     }
 
+    @Override
+    public IBatchProcessor getPostProcessor() {
+        return postProcessor;
+    }
+
     @Override
     public IChunkSet processSet(IChunk chunk, IChunkGet get, IChunkSet set) {
         return getProcessor().processSet(chunk, get, set);
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        return getPostProcessor().postProcessSet(chunk, get, set);
+    }
+
     @Override
     public void flush() {
         getProcessor().flush();
@@ -28,6 +41,11 @@ public class BatchProcessorHolder implements IBatchProcessorHolder {
         this.processor = set;
     }
 
+    @Override
+    public void setPostProcessor(IBatchProcessor set) {
+        this.postProcessor = set;
+    }
+
     @Override
     public String toString() {
         IBatchProcessor tmp = getProcessor();

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/ChunkSendProcessor.java

@@ -12,6 +12,8 @@ import com.sk89q.worldedit.extent.Extent;
 import com.sk89q.worldedit.world.World;
 
 import java.util.Collection;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
 import java.util.function.Supplier;
 
 public class ChunkSendProcessor implements IBatchProcessor {
@@ -65,6 +67,12 @@ public class ChunkSendProcessor implements IBatchProcessor {
         return set;
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        // Doesn't need to do anything
+        return CompletableFuture.completedFuture(set);
+    }
+
     public IBlocks combine(IChunk chunk, IChunkGet get, IChunkSet set) {
         return new CombinedBlocks(get, set, 0);
     }

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/EmptyBatchProcessor.java

@@ -9,6 +9,9 @@ import com.sk89q.worldedit.extent.Extent;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
+
 public final class EmptyBatchProcessor implements IBatchProcessor {
     private static final EmptyBatchProcessor instance = new EmptyBatchProcessor();
 
@@ -26,11 +29,23 @@ public final class EmptyBatchProcessor implements IBatchProcessor {
         return set;
     }
 
+    @Override
+    @NotNull
+    public Future<IChunkSet> postProcessSet(@Nullable IChunk chunk, @Nullable IChunkGet get, @Nullable IChunkSet set) {
+        // Doesn't need to do anything
+        return CompletableFuture.completedFuture(set);
+    }
+
     @NotNull
     public IBatchProcessor join(@Nullable IBatchProcessor other) {
         return other;
     }
 
+    @NotNull
+    public IBatchProcessor joinPost(@Nullable IBatchProcessor other) {
+        return other;
+    }
+
     private EmptyBatchProcessor() {
     }
 

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/ExtentBatchProcessorHolder.java

@@ -1,6 +1,7 @@
 package com.boydti.fawe.beta.implementation.processors;
 
 import com.boydti.fawe.beta.IBatchProcessor;
+import com.boydti.fawe.config.Settings;
 import com.boydti.fawe.object.changeset.AbstractChangeSet;
 import com.sk89q.worldedit.extent.Extent;
 
@@ -11,10 +12,20 @@ public abstract class ExtentBatchProcessorHolder extends BatchProcessorHolder im
         return this;
     }
 
+    @Override
+    public Extent addPostProcessor(IBatchProcessor processor) {
+        joinPost(processor);
+        return this;
+    }
+
     @Override
     public Extent enableHistory(AbstractChangeSet changeSet) {
+        if (Settings.IMP.EXPERIMENTAL.SEND_BEFORE_HISTORY) {
+            return this.addPostProcessor(changeSet);
+        } else {
             return this.addProcessor(changeSet);
         }
+    }
 
     @Override
     public Extent disableHistory() {

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/IBatchProcessorHolder.java

@@ -6,6 +6,8 @@ import com.boydti.fawe.beta.IChunkGet;
 import com.boydti.fawe.beta.IChunkSet;
 import com.sk89q.worldedit.extent.Extent;
 
+import java.util.concurrent.Future;
+
 /**
  * Holds a batch processor
  * (Join and remove operations affect the held processor)
@@ -13,17 +15,26 @@ import com.sk89q.worldedit.extent.Extent;
 public interface IBatchProcessorHolder extends IBatchProcessor {
     IBatchProcessor getProcessor();
 
+    IBatchProcessor getPostProcessor();
+
     /**
      * set the held processor
      * @param set
      */
     void setProcessor(IBatchProcessor set);
 
+    void setPostProcessor(IBatchProcessor set);
+
     @Override
     default IChunkSet processSet(IChunk chunk, IChunkGet get, IChunkSet set) {
         return getProcessor().processSet(chunk, get, set);
     }
 
+    @Override
+    default Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        return getPostProcessor().postProcessSet(chunk, get, set);
+    }
+
     @Override
     default boolean processGet(int chunkX, int chunkZ) {
         return getProcessor().processGet(chunkX, chunkZ);
@@ -40,6 +51,12 @@ public interface IBatchProcessorHolder extends IBatchProcessor {
         return this;
     }
 
+    @Override
+    default IBatchProcessor joinPost(IBatchProcessor other) {
+        setPostProcessor(getPostProcessor().joinPost(other));
+        return this;
+    }
+
     @Override
     default <T extends IBatchProcessor> IBatchProcessor remove(Class<T> clazz) {
         setProcessor(getProcessor().remove(clazz));

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/MultiBatchProcessor.java

@@ -14,6 +14,8 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
 import java.util.Map;
 import java.util.function.Supplier;
 
@@ -84,6 +86,23 @@ public class MultiBatchProcessor implements IBatchProcessor {
         }
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        try {
+            for (int i = processors.length - 1 ; i >= 0; i--) {
+                IBatchProcessor processor = processors[i];
+                set = processor.postProcessSet(chunk, get, set).get();
+                if (set == null) {
+                    return null;
+                }
+            }
+            return CompletableFuture.completedFuture(set);
+        } catch (Throwable e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+
     @Override
     public boolean processGet(int chunkX, int chunkZ) {
         for (IBatchProcessor processor : this.processors) {
@@ -121,6 +140,18 @@ public class MultiBatchProcessor implements IBatchProcessor {
         return this;
     }
 
+    @Override
+    public IBatchProcessor joinPost(IBatchProcessor other) {
+        if (other instanceof MultiBatchProcessor) {
+            for (IBatchProcessor processor : ((MultiBatchProcessor) other).processors) {
+                addBatchProcessor(processor);
+            }
+        } else {
+            addBatchProcessor(other);
+        }
+        return this;
+    }
+
     @Override
     public void flush() {
         for (IBatchProcessor processor : this.processors) processor.flush();

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/processors/NullProcessor.java

@@ -9,6 +9,8 @@ import com.sk89q.worldedit.extent.NullExtent;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.concurrent.Future;
+
 public final class NullProcessor implements IBatchProcessor {
     private static final NullProcessor instance = new NullProcessor();
 
@@ -21,6 +23,11 @@ public final class NullProcessor implements IBatchProcessor {
         return null;
     }
 
+    @Nullable
+    public Future<IChunkSet> postProcessSet(@NotNull IChunk chunk, @NotNull IChunkGet get, @NotNull IChunkSet set) {
+        return null;
+    }
+
     @NotNull
     public Extent construct(@NotNull Extent child) {
         return new NullExtent();

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/queue/ParallelQueueExtent.java

@@ -43,14 +43,16 @@ public class ParallelQueueExtent extends PassthroughExtent implements IQueueWrap
     private final World world;
     private final QueueHandler handler;
     private final BatchProcessorHolder processor;
+    private final BatchProcessorHolder postProcessor;
     private int changes;
     private final boolean fastmode;
 
     public ParallelQueueExtent(QueueHandler handler, World world, boolean fastmode) {
-        super(handler.getQueue(world, new BatchProcessorHolder()));
+        super(handler.getQueue(world, new BatchProcessorHolder(), new BatchProcessorHolder()));
         this.world = world;
         this.handler = handler;
         this.processor = (BatchProcessorHolder) getExtent().getProcessor();
+        this.postProcessor = (BatchProcessorHolder) getExtent().getPostProcessor();
         this.fastmode = fastmode;
     }
 
@@ -63,19 +65,21 @@ public class ParallelQueueExtent extends PassthroughExtent implements IQueueWrap
     public boolean cancel() {
         if (super.cancel()) {
             processor.setProcessor(new NullExtent(this, FaweCache.MANUAL));
+            postProcessor.setPostProcessor(new NullExtent(this, FaweCache.MANUAL));
             return true;
         }
         return false;
     }
 
     private IQueueExtent<IQueueChunk> getNewQueue() {
-        return wrapQueue(handler.getQueue(this.world, this.processor));
+        return wrapQueue(handler.getQueue(this.world, this.processor, this.postProcessor));
     }
 
     @Override
     public IQueueExtent<IQueueChunk> wrapQueue(IQueueExtent<IQueueChunk> queue) {
         // TODO wrap
         queue.setProcessor(this.processor);
+        queue.setPostProcessor(this.postProcessor);
         return queue;
     }
 

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/queue/QueueHandler.java

@@ -280,10 +280,10 @@ public abstract class QueueHandler implements Trimable, Runnable {
     public abstract void endSet(boolean parallel);
 
     public IQueueExtent<IQueueChunk> getQueue(World world) {
-        return getQueue(world, null);
+        return getQueue(world, null, null);
     }
 
-    public IQueueExtent<IQueueChunk> getQueue(World world, IBatchProcessor processor) {
+    public IQueueExtent<IQueueChunk> getQueue(World world, IBatchProcessor processor, IBatchProcessor postProcessor) {
         final IQueueExtent<IQueueChunk> queue = pool();
         IChunkCache<IChunkGet> cacheGet = getOrCreateWorldCache(world);
         IChunkCache<IChunkSet> set = null; // TODO cache?
@@ -291,6 +291,9 @@ public abstract class QueueHandler implements Trimable, Runnable {
         if (processor != null) {
             queue.setProcessor(processor);
         }
+        if (postProcessor != null) {
+            queue.setPostProcessor(postProcessor);
+        }
         return queue;
     }
 

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/queue/SingleThreadQueueExtent.java

@@ -113,6 +113,7 @@ public class SingleThreadQueueExtent extends ExtentBatchProcessorHolder implemen
         this.currentThread = null;
         this.initialized = false;
         this.setProcessor(EmptyBatchProcessor.getInstance());
+        this.setPostProcessor(EmptyBatchProcessor.getInstance());
     }
 
     /**
@@ -132,6 +133,7 @@ public class SingleThreadQueueExtent extends ExtentBatchProcessorHolder implemen
         this.cacheGet = get;
         this.cacheSet = set;
         this.setProcessor(EmptyBatchProcessor.getInstance());
+        this.setPostProcessor(EmptyBatchProcessor.getInstance());
         initialized = true;
     }
 

worldedit-core/src/main/java/com/boydti/fawe/config/Settings.java

@@ -393,6 +393,12 @@ public class Settings extends Config {
             "This will increase time taken slightly."
         })
         public boolean ALLOW_TICK_EXISTING = true;
+        @Comment({
+            "Do not wait for a chunk's history to save before sending it",
+            " - Undo/redo commands will wait until the history has been written to disk before executing",
+            " - Requires combine_stages = true"
+        })
+        public boolean SEND_BEFORE_HISTORY = true;
     }
 
     public static class PLOTSQUARED_INTEGRATION {

worldedit-core/src/main/java/com/boydti/fawe/jnbt/anvil/MCAChunk.java

@@ -62,6 +62,8 @@ public class MCAChunk implements IChunk {
     public int chunkX;
     public int chunkZ;
 
+    private boolean createCopy = false;
+
     public MCAChunk() {}
 
     private boolean readLayer(Section section) {
@@ -602,6 +604,14 @@ public class MCAChunk implements IChunk {
         return this.entities.get(uuid);
     }
 
+    @Override public void setCreateCopy(boolean createCopy) {
+        this.createCopy = createCopy;
+    }
+
+    @Override public boolean isCreateCopy() {
+        return createCopy;
+    }
+
     @Override
     public Future call(IChunkSet set, Runnable finalize) {
         return null;

worldedit-core/src/main/java/com/boydti/fawe/object/changeset/AbstractChangeSet.java

@@ -59,7 +59,6 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
         if (closed) {
             return;
         }
-        closed = true;
         waitingAsync.incrementAndGet();
         TaskManager.IMP.async(() -> {
             waitingAsync.decrementAndGet();
@@ -97,8 +96,8 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
     @Override
     public void close() throws IOException {
         if (!closed) {
-            closed = true;
             flush();
+            closed = true;
         }
     }
 
@@ -204,6 +203,11 @@ public abstract class AbstractChangeSet implements ChangeSet, IBatchProcessor {
         return set;
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(final IChunk chunk, final IChunkGet get,final  IChunkSet set) {
+        return (Future<IChunkSet>) addWriteTask(() -> processSet(chunk, get, set));
+    }
+
     public abstract void addTileCreate(CompoundTag tag);
 
     public abstract void addTileRemove(CompoundTag tag);

worldedit-core/src/main/java/com/boydti/fawe/object/extent/HeightBoundExtent.java

@@ -10,6 +10,8 @@ import com.sk89q.worldedit.regions.Region;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
 
 public class HeightBoundExtent extends FaweRegionExtent {
 
@@ -51,4 +53,9 @@ public class HeightBoundExtent extends FaweRegionExtent {
         }
         return null;
     }
+
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        return CompletableFuture.completedFuture(set);
+    }
 }

worldedit-core/src/main/java/com/boydti/fawe/object/extent/MultiRegionExtent.java

@@ -10,6 +10,7 @@ import com.sk89q.worldedit.regions.RegionIntersection;
 
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.concurrent.Future;
 
 public class MultiRegionExtent extends FaweRegionExtent {
 
@@ -86,4 +87,9 @@ public class MultiRegionExtent extends FaweRegionExtent {
     public IChunkSet processSet(IChunk chunk, IChunkGet get, IChunkSet set) {
         return intersection.processSet(chunk, get, set);
     }
+
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        return intersection.postProcessSet(chunk, get, set);
+    }
 }

worldedit-core/src/main/java/com/boydti/fawe/object/extent/NullExtent.java

@@ -37,6 +37,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.Future;
 import javax.annotation.Nullable;
 
 //todo This should be removed in favor of com.sk89q.worldedit.extent.NullExtent
@@ -340,6 +341,11 @@ public class NullExtent extends FaweRegionExtent implements IBatchProcessor {
         throw reason;
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        throw reason;
+    }
+
     @Override
     public boolean processGet(int chunkX, int chunkZ) {
         throw reason;

worldedit-core/src/main/java/com/boydti/fawe/object/extent/SingleRegionExtent.java

@@ -9,6 +9,7 @@ import com.sk89q.worldedit.regions.Region;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.concurrent.Future;
 
 public class SingleRegionExtent extends FaweRegionExtent {
 
@@ -44,6 +45,11 @@ public class SingleRegionExtent extends FaweRegionExtent {
         return region.processSet(chunk, get, set);
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        return region.postProcessSet(chunk, get, set);
+    }
+
     @Override
     public boolean processGet(int chunkX, int chunkZ) {
         return region.containsChunk(chunkX, chunkZ);

worldedit-core/src/main/java/com/sk89q/worldedit/extent/AbstractDelegateExtent.java

@@ -317,6 +317,24 @@ public class AbstractDelegateExtent implements Extent {
         return this;
     }
 
+    @Override
+    public Extent addPostProcessor(IBatchProcessor processor) {
+        if (Settings.IMP.EXPERIMENTAL.OTHER) {
+            logger.info("addPostProcessor Info: \t " + processor.getClass().getName());
+            logger.info("The following is not an error or a crash:");
+            StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
+            for (StackTraceElement stackTraceElement : stackTrace) {
+                logger.info(stackTraceElement.toString());
+            }
+
+        }
+        Extent result = this.extent.addPostProcessor(processor);
+        if (result != this.extent) {
+            new ExtentTraverser<Extent>(this).setNext(result);
+        }
+        return this;
+    }
+
     @Override
     public Extent disableHistory() {
         Extent result = this.extent.disableHistory();

worldedit-core/src/main/java/com/sk89q/worldedit/extent/Extent.java

@@ -23,6 +23,7 @@ import com.boydti.fawe.FaweCache;
 import com.boydti.fawe.beta.Filter;
 import com.boydti.fawe.beta.IBatchProcessor;
 import com.boydti.fawe.beta.implementation.filter.block.ExtentFilterBlock;
+import com.boydti.fawe.config.Settings;
 import com.boydti.fawe.object.changeset.AbstractChangeSet;
 import com.boydti.fawe.object.clipboard.WorldCopyClipboard;
 import com.boydti.fawe.object.exception.FaweException;
@@ -671,9 +672,17 @@ public interface Extent extends InputExtent, OutputExtent {
         return processor.construct(this);
     }
 
+    default Extent addPostProcessor(IBatchProcessor processor) {
+        return processor.construct(this);
+    }
+
     default Extent enableHistory(AbstractChangeSet changeSet) {
+        if (Settings.IMP.EXPERIMENTAL.SEND_BEFORE_HISTORY) {
+            return addPostProcessor(changeSet);
+        } else {
             return addProcessor(changeSet);
         }
+    }
 
     default Extent disableHistory() {
         return this;

worldedit-core/src/main/java/com/sk89q/worldedit/extent/MaskingExtent.java

@@ -36,6 +36,9 @@ import com.sk89q.worldedit.math.BlockVector3;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BlockStateHolder;
 
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
+
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
@@ -106,6 +109,12 @@ public class MaskingExtent extends AbstractDelegateExtent implements IBatchProce
         return filter.filter(chunk, get, set, MaskingExtent.this);
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        // This should not do anything otherwise dangerous...
+        return CompletableFuture.completedFuture(set);
+    }
+
     @Override
     public void applyBlock(final FilterBlock block) {
         if (!this.mask.test(block)) {

worldedit-core/src/main/java/com/sk89q/worldedit/regions/Region.java

@@ -37,6 +37,8 @@ import com.sk89q.worldedit.world.World;
 
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
 import javax.annotation.Nullable;
 
 /**
@@ -350,6 +352,12 @@ public interface Region extends Iterable<BlockVector3>, Cloneable, IBatchProcess
         }
     }
 
+    @Override
+    default Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        // Doesn't need to do anything
+        return CompletableFuture.completedFuture(set);
+    }
+
     @Override
     default Extent construct(Extent child) {
         if (isGlobal()) {

worldedit-core/src/main/java/com/sk89q/worldedit/regions/RegionIntersection.java

@@ -34,6 +34,8 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
@@ -170,6 +172,12 @@ public class RegionIntersection extends AbstractRegion {
         return null;
     }
 
+    @Override
+    public Future<IChunkSet> postProcessSet(IChunk chunk, IChunkGet get, IChunkSet set) {
+        // Doesn't need to do anything
+        return CompletableFuture.completedFuture(set);
+    }
+
     public List<Region> getRegions() {
         return regions;
     }