Don't synchronise across the entire edit for a single ChunkSection load (speed boost)

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_15_2/BukkitGetBlocks_1_15_2.java

@@ -825,7 +825,7 @@ public class BukkitGetBlocks_1_15_2 extends CharGetBlocks {
             return super.trim(true);
         } else {
             for (int i = 0; i < 16; i++) {
-                if (!hasSection(i) || super.sections[i] == CharBlocks.EMPTY) {
+                if (!hasSection(i) || !super.sections[i].isFull()) {
                     continue;
                 }
                 ChunkSection existing = getSections(true)[i];

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_1/BukkitGetBlocks_1_16_1.java

@@ -827,7 +827,7 @@ public class BukkitGetBlocks_1_16_1 extends CharGetBlocks {
             return super.trim(true);
         } else {
             for (int i = 0; i < 16; i++) {
-                if (!hasSection(i) || super.sections[i] == CharBlocks.EMPTY) {
+                if (!hasSection(i) || !super.sections[i].isFull()) {
                     continue;
                 }
                 ChunkSection existing = getSections(true)[i];

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_2/BukkitGetBlocks_1_16_2.java

@@ -830,7 +830,7 @@ public class BukkitGetBlocks_1_16_2 extends CharGetBlocks {
             return super.trim(true);
         } else {
             for (int i = 0; i < 16; i++) {
-                if (!hasSection(i) || super.sections[i] == CharBlocks.EMPTY) {
+                if (!hasSection(i) || !super.sections[i].isFull()) {
                     continue;
                 }
                 ChunkSection existing = getSections(true)[i];

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/mc1_16_4/BukkitGetBlocks_1_16_4.java

@@ -830,7 +830,7 @@ public class BukkitGetBlocks_1_16_4 extends CharGetBlocks {
             return super.trim(true);
         } else {
             for (int i = 0; i < 16; i++) {
-                if (!hasSection(i) || super.sections[i] == CharBlocks.EMPTY) {
+                if (!hasSection(i) || !super.sections[i].isFull()) {
                     continue;
                 }
                 ChunkSection existing = getSections(true)[i];

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

@@ -9,17 +9,24 @@ import org.jetbrains.annotations.Range;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.Arrays;
+
 public abstract class CharBlocks implements IBlocks {
 
     public static final Logger logger = LoggerFactory.getLogger(CharBlocks.class);
 
-    public static final Section FULL = new Section() {
+    protected final Section FULL = new Section() {
         @Override
         public final char[] get(CharBlocks blocks, int layer) {
             return blocks.blocks[layer];
         }
+
+        @Override
+        public final boolean isFull() {
+            return true;
+        }
     };
-    public static final Section EMPTY = new Section() {
+    protected final Section EMPTY = new Section() {
         @Override
         public final synchronized char[] get(CharBlocks blocks, int layer) {
             char[] arr = blocks.blocks[layer];
@@ -39,15 +46,22 @@ public abstract class CharBlocks implements IBlocks {
             }
             return arr;
         }
+
+        @Override
+        public final boolean isFull() {
+            return false;
+        }
     };
     public final char[][] blocks;
     public final Section[] sections;
+    private final Object[] loadLock = new Object[16];
 
     public CharBlocks() {
         blocks = new char[16][];
         sections = new Section[16];
         for (int i = 0; i < 16; i++) {
             sections[i] = EMPTY;
+            loadLock[i] = new Object();
         }
     }
 
@@ -55,7 +69,7 @@ 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].isFull() && blocks[i] != null) {
                 blocks[i] = null;
             } else {
                 result = false;
@@ -67,7 +81,7 @@ public abstract class CharBlocks implements IBlocks {
     @Override
     public boolean trim(boolean aggressive, int layer) {
         boolean result = true;
-        if (sections[layer] == EMPTY && blocks[layer] != null) {
+        if (!sections[layer].isFull() && blocks[layer] != null) {
             blocks[layer] = null;
         } else {
             result = false;
@@ -99,12 +113,18 @@ public abstract class CharBlocks implements IBlocks {
 
     @Override
     public boolean hasSection(@Range(from = 0, to = 15) int layer) {
-        return sections[layer] == FULL;
+        return sections[layer].isFull();
     }
 
     @Override
     public char[] load(@Range(from = 0, to = 15) int layer) {
-        return sections[layer].get(this, layer);
+        Section section = sections[layer];
+        if (section.isFull()) {
+            return section.get(this, layer);
+        }
+        synchronized (loadLock[layer]) {
+            return sections[layer].get(this, layer);
+        }
     }
 
     @Override
@@ -149,6 +169,8 @@ public abstract class CharBlocks implements IBlocks {
 
         public abstract char[] get(CharBlocks blocks, @Range(from = 0, to = 15) int layer);
 
+        public abstract boolean isFull();
+
         public final char get(CharBlocks blocks, @Range(from = 0, to = 15) int layer, int index) {
             return get(blocks, layer)[index];
         }