From 3f92f12e89a80e38c79e04c74257cf044d23f2fe Mon Sep 17 00:00:00 2001
From: Jesse Boyd <jessepaleg@gmail.com>
Date: Sun, 17 Nov 2019 20:02:33 +0000
Subject: [PATCH] synchronize char blocks

---
 .../adapter/mc1_14/BukkitGetBlocks_1_14.java  |  2 ++
 .../implementation/blocks/CharBlocks.java     | 22 ++++++++++++-------
 .../implementation/blocks/CharGetBlocks.java  |  8 ++++---
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_14/BukkitGetBlocks_1_14.java b/worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_14/BukkitGetBlocks_1_14.java
index 3de8bc89b..a5829ec5b 100644
--- a/worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_14/BukkitGetBlocks_1_14.java
+++ b/worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_14/BukkitGetBlocks_1_14.java
@@ -1,5 +1,6 @@
 package com.boydti.fawe.bukkit.adapter.mc1_14;
 
+import static com.google.common.base.Preconditions.checkNotNull;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import com.boydti.fawe.Fawe;
@@ -210,6 +211,7 @@ public class BukkitGetBlocks_1_14 extends CharGetBlocks {
     }
 
     private void updateGet(BukkitGetBlocks_1_14 get, Chunk nmsChunk, ChunkSection[] sections, ChunkSection section, char[] arr, int layer) {
+        checkNotNull(arr);
         synchronized (get) {
             if (this.nmsChunk != nmsChunk) {
                 this.nmsChunk = nmsChunk;
diff --git a/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharBlocks.java b/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharBlocks.java
index 5cd894008..fe5ec23ad 100644
--- a/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharBlocks.java
+++ b/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharBlocks.java
@@ -16,7 +16,6 @@ public abstract class CharBlocks implements IBlocks {
     public static final Section EMPTY = new Section() {
         @Override
         public final char[] get(CharBlocks blocks, int layer) {
-            blocks.sections[layer] = FULL;
             char[] arr = blocks.blocks[layer];
             if (arr == null) {
                 arr = blocks.blocks[layer] = blocks.update(layer, null);
@@ -25,6 +24,14 @@ public abstract class CharBlocks implements IBlocks {
                 }
             } else {
                 blocks.blocks[layer] = blocks.update(layer, arr);
+                if (blocks.blocks[layer] == null) {
+                    throw new IllegalStateException("Array cannot be null (update): " + blocks.getClass());
+                }
+            }
+            synchronized (this) {
+                if (blocks.blocks[layer] != null) {
+                    blocks.sections[layer] = FULL;
+                }
             }
             return arr;
         }
@@ -32,11 +39,6 @@ public abstract class CharBlocks implements IBlocks {
     public final char[][] blocks;
     public final Section[] sections;
 
-    public CharBlocks(CharBlocks other) {
-        this.blocks = other.blocks;
-        this.sections = other.sections;
-    }
-
     public CharBlocks() {
         blocks = new char[16][];
         sections = new Section[16];
@@ -49,8 +51,12 @@ public abstract class CharBlocks implements IBlocks {
     public boolean trim(boolean aggressive) {
         boolean result = true;
         for (int i = 0; i < 16; i++) {
-            if (sections[i] == EMPTY) {
-                blocks[i] = null;
+            if (sections[i] == EMPTY && blocks[i] != null) {
+                synchronized (this) {
+                    if (sections[i] == EMPTY && blocks[i] != null) {
+                        blocks[i] = null;
+                    }
+                }
             } else {
                 result = false;
             }
diff --git a/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharGetBlocks.java b/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharGetBlocks.java
index 9304969f3..a0ff14a58 100644
--- a/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharGetBlocks.java
+++ b/worldedit-core/src/main/java/com/boydti/fawe/beta/implementation/blocks/CharGetBlocks.java
@@ -21,9 +21,11 @@ public abstract class CharGetBlocks extends CharBlocks implements IChunkGet {
 
     @Override
     public boolean trim(boolean aggressive) {
-        for (int i = 0; i < 16; i++) {
-            sections[i] = EMPTY;
-            blocks[i] = null;
+        synchronized (this) {
+            for (int i = 0; i < 16; i++) {
+                sections[i] = EMPTY;
+                blocks[i] = null;
+            }
         }
         return true;
     }