better locking of lighting and use correct method for relight without removing first

Fixes #847

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/lighting/NMSRelighter.java

@@ -71,6 +71,7 @@ public class NMSRelighter implements Relighter {
     private final int maxY;
     private final boolean calculateHeightMaps;
     private final ReentrantLock lightingLock;
+    private final AtomicBoolean finished = new AtomicBoolean(false);
     private boolean removeFirst;
 
     public NMSRelighter(IQueueExtent<IQueueChunk> queue, boolean calculateHeightMaps) {
@@ -99,6 +100,11 @@ public class NMSRelighter implements Relighter {
         return lightingLock;
     }
 
+    @Override
+    public boolean isFinished() {
+        return finished.get();
+    }
+
     @Override public synchronized void removeAndRelight(boolean sky) {
         removeFirst = true;
         fixLightingSafe(sky);
@@ -839,10 +845,12 @@ public class NMSRelighter implements Relighter {
         }
         if (Settings.IMP.LIGHTING.ASYNC) {
             queue.flush();
+            finished.set(true);
         } else {
             TaskManager.IMP.sync(new RunnableVal<Object>() {
                 @Override public void run(Object value) {
                     queue.flush();
+                    finished.set(true);
                 }
             });
         }
@@ -873,6 +881,7 @@ public class NMSRelighter implements Relighter {
                     Fawe.imp().getPlatformAdapter().sendChunk(chunk.getOrCreateGet(), bitMask, true);
                     iter.remove();
                 }
+                finished.set(true);
             }
         };
         if (Settings.IMP.LIGHTING.ASYNC) {

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/lighting/NullRelighter.java

@@ -53,4 +53,9 @@ public class NullRelighter implements Relighter {
     public ReentrantLock getLock() {
         return null;
     }
+
+    @Override
+    public boolean isFinished() {
+        return true;
+    }
 }

worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/lighting/Relighter.java

@@ -70,6 +70,13 @@ public interface Relighter {
 
     ReentrantLock getLock();
 
+    /**
+     * Returns true if the Relighter has been flushed
+     *
+     * @return true if finished
+     */
+    boolean isFinished();
+
     class SkipReason {
         public static final byte NONE = 0;
         public static final byte AIR = 1;

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

@@ -1098,18 +1098,15 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
         limit.set(originalLimit);
         try {
             if (relighter != null && !(relighter instanceof NullRelighter)) {
-                // Only relight once!
-                if (Settings.IMP.LIGHTING.DELAY_PACKET_SENDING && !relighter.getLock().tryLock()) {
-                    relighter.getLock().lock();
-                    relighter.getLock().unlock();
-                } else {
-                    if (Settings.IMP.LIGHTING.REMOVE_FIRST) {
-                        relighter.removeAndRelight(true);
-                    } else {
-                        relighter.fixSkyLighting();
-                        relighter.fixBlockLighting();
-                    }
-                    if (Settings.IMP.LIGHTING.DELAY_PACKET_SENDING) {
+                // Don't relight twice!
+                if (!relighter.isFinished() && relighter.getLock().tryLock()) {
+                    try {
+                        if (Settings.IMP.LIGHTING.REMOVE_FIRST) {
+                            relighter.removeAndRelight(true);
+                        } else {
+                            relighter.fixLightingSafe(true);
+                        }
+                    } finally {
                         relighter.getLock().unlock();
                     }
                 }