From e453a0f9b510b5cf2916f46cbb4702d7ca0b3b7b Mon Sep 17 00:00:00 2001
From: themode <themode@outlook.fr>
Date: Fri, 20 Nov 2020 08:39:06 +0100
Subject: [PATCH] Added Chunk#getLastChangeTime

---
 .../net/minestom/server/instance/Chunk.java   | 11 ++++++
 .../server/instance/DynamicChunk.java         | 34 ++++++++++++++-----
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/src/main/java/net/minestom/server/instance/Chunk.java b/src/main/java/net/minestom/server/instance/Chunk.java
index 7b5cad348..92e37c495 100644
--- a/src/main/java/net/minestom/server/instance/Chunk.java
+++ b/src/main/java/net/minestom/server/instance/Chunk.java
@@ -191,6 +191,17 @@ public abstract class Chunk implements Viewable, DataContainer {
     @NotNull
     public abstract Set<Integer> getBlockEntities();
 
+    /**
+     * Gets the last time that this chunk changed.
+     * <p>
+     * "Change" means here data used in {@link ChunkDataPacket}.
+     * It is necessary to see if the cached version of this chunk can be used
+     * instead of re writing and compressing everything.
+     *
+     * @return the last change time in milliseconds
+     */
+    public abstract long getLastChangeTime();
+
     /**
      * Serializes the chunk into bytes.
      *
diff --git a/src/main/java/net/minestom/server/instance/DynamicChunk.java b/src/main/java/net/minestom/server/instance/DynamicChunk.java
index 4def0f0b1..80929c9e9 100644
--- a/src/main/java/net/minestom/server/instance/DynamicChunk.java
+++ b/src/main/java/net/minestom/server/instance/DynamicChunk.java
@@ -57,6 +57,8 @@ public class DynamicChunk extends Chunk {
     // Block entities
     protected final Set<Integer> blockEntities = new CopyOnWriteArraySet<>();
 
+    private long lastChangeTime;
+
     public DynamicChunk(@Nullable Biome[] biomes, int chunkX, int chunkZ,
                         @NotNull PaletteStorage blockPalette, @NotNull PaletteStorage customBlockPalette) {
         super(biomes, chunkX, chunkZ, true);
@@ -86,8 +88,8 @@ public class DynamicChunk extends Chunk {
         // True if the block is not complete air without any custom block capabilities
         final boolean hasBlock = blockStateId != 0 || customBlockId != 0;
 
-        this.blockPalette.setBlockAt(x, y, z, blockStateId);
-        this.customBlockPalette.setBlockAt(x, y, z, customBlockId);
+        setBlockAt(blockPalette, x, y, z, blockStateId);
+        setBlockAt(customBlockPalette, x, y, z, customBlockId);
 
         if (!hasBlock) {
             // Block has been deleted, clear cache and return
@@ -155,23 +157,23 @@ public class DynamicChunk extends Chunk {
 
     @Override
     public short getBlockStateId(int x, int y, int z) {
-        return this.blockPalette.getBlockAt(x, y, z);
+        return getBlockAt(blockPalette, x, y, z);
     }
 
     @Override
     public short getCustomBlockId(int x, int y, int z) {
-        return customBlockPalette.getBlockAt(x, y, z);
+        return getBlockAt(customBlockPalette, x, y, z);
     }
 
     @Override
     protected void refreshBlockValue(int x, int y, int z, short blockStateId, short customBlockId) {
-        this.blockPalette.setBlockAt(x, y, z, blockStateId);
-        this.customBlockPalette.setBlockAt(x, y, z, customBlockId);
+        setBlockAt(blockPalette, x, y, z, blockStateId);
+        setBlockAt(customBlockPalette, x, y, z, customBlockId);
     }
 
     @Override
     protected void refreshBlockStateId(int x, int y, int z, short blockStateId) {
-        this.blockPalette.setBlockAt(x, y, z, blockStateId);
+        setBlockAt(blockPalette, x, y, z, blockStateId);
     }
 
     @Override
@@ -195,6 +197,11 @@ public class DynamicChunk extends Chunk {
         return blockEntities;
     }
 
+    @Override
+    public long getLastChangeTime() {
+        return lastChangeTime;
+    }
+
     /**
      * Serialize this {@link Chunk} based on {@link #readChunk(BinaryReader, ChunkCallback)}
      * <p>
@@ -242,8 +249,8 @@ public class DynamicChunk extends Chunk {
                     for (byte z = 0; z < CHUNK_SIZE_Z; z++) {
                         final int index = getBlockIndex(x, y, z);
 
-                        final short blockStateId = blockPalette.getBlockAt(x, y, z);
-                        final short customBlockId = customBlockPalette.getBlockAt(x, y, z);
+                        final short blockStateId = getBlockAt(blockPalette, x, y, z);
+                        final short customBlockId = getBlockAt(customBlockPalette, x, y, z);
 
                         // No block at the position
                         if (blockStateId == 0 && customBlockId == 0)
@@ -400,4 +407,13 @@ public class DynamicChunk extends Chunk {
 
         return dynamicChunk;
     }
+
+    private short getBlockAt(@NotNull PaletteStorage paletteStorage, int x, int y, int z) {
+        return paletteStorage.getBlockAt(x, y, z);
+    }
+
+    private void setBlockAt(@NotNull PaletteStorage paletteStorage, int x, int y, int z, short blockId) {
+        paletteStorage.setBlockAt(x, y, z, blockId);
+        this.lastChangeTime = System.currentTimeMillis();
+    }
 }
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