Flush clipboard rather than close on player disconnect

Addresses #1291

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/LazyClipboardHolder.java

@@ -61,4 +61,11 @@ public class LazyClipboardHolder extends URIClipboardHolder {
         clipboard = null;
     }
 
+    @Override
+    public synchronized void flush() {
+        if (clipboard instanceof BlockArrayClipboard) {
+            clipboard.flush();
+        }
+    }
+
 }

worldedit-core/src/main/java/com/fastasyncworldedit/core/extent/clipboard/MultiClipboardHolder.java

@@ -3,6 +3,7 @@ package com.fastasyncworldedit.core.extent.clipboard;
 import com.sk89q.worldedit.extent.clipboard.Clipboard;
 import com.sk89q.worldedit.session.ClipboardHolder;
 
+import java.io.IOException;
 import java.net.URI;
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -183,4 +184,15 @@ public class MultiClipboardHolder extends URIClipboardHolder {
         }
     }
 
+    @Override
+    public void flush() {
+        for (ClipboardHolder holder : holders) {
+            try {
+                holder.flush();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
 }

worldedit-core/src/main/java/com/sk89q/worldedit/LocalSession.java

@@ -840,12 +840,16 @@ public class LocalSession implements TextureHolder {
     }
 
     /**
-     * Ensure the player's clipboard is closed. (will only do something with clipboard-on-disk)
+     * Ensure the player's clipboard is flushed. (will only do something with clipboard-on-disk)
      */
-    public void closeClipboard() {
+    public void flushClipboard() {
         synchronized (clipboardLock) {
             if (this.clipboard != null) {
-                this.clipboard.close();
+                try {
+                    this.clipboard.flush();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
             }
         }
     }

worldedit-core/src/main/java/com/sk89q/worldedit/entity/Player.java

@@ -391,7 +391,7 @@ public interface Player extends Entity, Actor {
      */
     default void unregister() {
         cancel(true);
-        getSession().closeClipboard();
+        getSession().flushClipboard();
         if (Settings.IMP.HISTORY.DELETE_ON_LOGOUT) {
             getSession().clearHistory();
         }

worldedit-core/src/main/java/com/sk89q/worldedit/session/ClipboardHolder.java

@@ -24,6 +24,9 @@ import com.sk89q.worldedit.extent.clipboard.Clipboard;
 import com.sk89q.worldedit.math.transform.Identity;
 import com.sk89q.worldedit.math.transform.Transform;
 
+import java.io.Closeable;
+import java.io.Flushable;
+import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
@@ -32,7 +35,8 @@ import static com.google.common.base.Preconditions.checkNotNull;
 /**
  * Holds the clipboard and the current transform on the clipboard.
  */
-public class ClipboardHolder {
+//FAWE start - closeable and flushable
+public class ClipboardHolder implements Closeable, Flushable {
 
     private Clipboard clipboard;
     private Transform transform = new Identity();
@@ -118,6 +122,7 @@ public class ClipboardHolder {
         return new PasteBuilder(this, targetExtent);
     }
 
+    @Override
     public void close() {
         if (clipboard != null) {
             clipboard.close();
@@ -125,5 +130,11 @@ public class ClipboardHolder {
         clipboard = null;
     }
 
+    @Override
+    public void flush() throws IOException {
+        if (clipboard != null) {
+            clipboard.flush();
+        }
+    }
 
 }