Add synchronization to CharBlocks (#963)

similar to ChunkHolder, it represents an internal chunk for which operations should not be accepted by multiple threads at once.

Co-authored-by: NotMyFault <mc.cache@web.de>

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

@@ -62,7 +62,7 @@ public abstract class CharBlocks implements IBlocks {
     }
 
     @Override
-    public boolean trim(boolean aggressive) {
+    public synchronized boolean trim(boolean aggressive) {
         boolean result = true;
         for (int i = 0; i < 16; i++) {
             if (!sections[i].isFull() && blocks[i] != null) {
@@ -75,7 +75,7 @@ public abstract class CharBlocks implements IBlocks {
     }
 
     @Override
-    public boolean trim(boolean aggressive, int layer) {
+    public synchronized boolean trim(boolean aggressive, int layer) {
         boolean result = true;
         if (!sections[layer].isFull() && blocks[layer] != null) {
             blocks[layer] = null;
@@ -86,18 +86,18 @@ public abstract class CharBlocks implements IBlocks {
     }
 
     @Override
-    public IChunkSet reset() {
+    public synchronized IChunkSet reset() {
         for (int i = 0; i < 16; i++) {
             sections[i] = EMPTY;
         }
         return null;
     }
 
-    public void reset(@Range(from = 0, to = 15) int layer) {
+    public synchronized void reset(@Range(from = 0, to = 15) int layer) {
         sections[layer] = EMPTY;
     }
 
-    public char[] update(int layer, char[] data) {
+    public synchronized char[] update(int layer, char[] data) {
         if (data == null) {
             return new char[4096];
         }
@@ -107,22 +107,23 @@ public abstract class CharBlocks implements IBlocks {
         return data;
     }
 
+    // Not synchronized as any subsequent methods called from this class will be, or the section shouldn't appear as loaded anyway.
     @Override
     public boolean hasSection(@Range(from = 0, to = 15) int layer) {
         return sections[layer].isFull();
     }
 
     @Override
-    public char[] load(@Range(from = 0, to = 15) int layer) {
+    public synchronized char[] load(@Range(from = 0, to = 15) int layer) {
         return sections[layer].get(this, layer);
     }
 
     @Override
-    public BlockState getBlock(int x, int y, int z) {
+    public synchronized BlockState getBlock(int x, int y, int z) {
         return BlockTypesCache.states[get(x, y, z)];
     }
 
-    public char get(int x, @Range(from = 0, to = 255) int y, int z) {
+    public synchronized char get(int x, @Range(from = 0, to = 255) int y, int z) {
         final int layer = y >> 4;
         final int index = (y & 15) << 8 | z << 4 | x;
         if (layer >= sections.length || layer < 0) {
@@ -131,6 +132,7 @@ public abstract class CharBlocks implements IBlocks {
         return sections[layer].get(this, layer, index);
     }
 
+    // Not synchronized as it refers to a synchronized method and includes nothing that requires synchronization
     public void set(int x, @Range(from = 0, to = 255) int y, int z, char value) {
         final int layer = y >> 4;
         final int index = (y & 15) << 8 | z << 4 | x;
@@ -147,11 +149,11 @@ public abstract class CharBlocks implements IBlocks {
         Section
      */
 
-    public final char get(@Range(from = 0, to = 15)int layer, int index) {
+    public synchronized final char get(@Range(from = 0, to = 15) int layer, int index) {
         return sections[layer].get(this, layer, index);
     }
 
-    public final void set(@Range(from = 0, to = 15) int layer, int index, char value) throws ArrayIndexOutOfBoundsException {
+    public synchronized final void set(@Range(from = 0, to = 15) int layer, int index, char value) throws ArrayIndexOutOfBoundsException {
         sections[layer].set(this, layer, index, value);
     }