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-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);