PaperMC/CraftBukkit-Patches/0105-Implement-Threaded-Bulk-Chunk-Compression-and-Cachin.patch

From 7acc085a95961261de6b3e68d46ec46e974a2c3b Mon Sep 17 00:00:00 2001
From: md_5 <git@md-5.net>
Date: Tue, 28 Jan 2014 20:32:07 +1100
Subject: [PATCH] Implement Threaded Bulk Chunk Compression and Caching


diff --git a/src/main/java/net/minecraft/server/PacketPlayOutMapChunkBulk.java b/src/main/java/net/minecraft/server/PacketPlayOutMapChunkBulk.java
index 30bf8a7..e05c870 100644
--- a/src/main/java/net/minecraft/server/PacketPlayOutMapChunkBulk.java
+++ b/src/main/java/net/minecraft/server/PacketPlayOutMapChunkBulk.java
@@ -8,13 +8,13 @@ import java.util.zip.Inflater;
 
 public class PacketPlayOutMapChunkBulk extends Packet {
 
-    private int[] a;
-    private int[] b;
+    public int[] a; // Spigot
+    public int[] b; // Spigot
     private int[] c;
     private int[] d;
-    private byte[] buffer;
+    public byte[] buffer; // Spigot
     private byte[][] inflatedBuffers;
-    private int size;
+    public int size; // Spigot
     private boolean h;
     private byte[] buildBuffer = new byte[0]; // CraftBukkit - remove static
     // CraftBukkit start
@@ -174,7 +174,7 @@ public class PacketPlayOutMapChunkBulk extends Packet {
     }
 
     public void b(PacketDataSerializer packetdataserializer) throws IOException { // CraftBukkit - throws IOException
-        compress(); // CraftBukkit
+        // compress(); // CraftBukkit // Spigot - removed
         packetdataserializer.writeShort(this.a.length);
         packetdataserializer.writeInt(this.size);
         packetdataserializer.writeBoolean(this.h);
diff --git a/src/main/java/net/minecraft/server/ServerConnectionChannel.java b/src/main/java/net/minecraft/server/ServerConnectionChannel.java
index fb95be4..2875c94 100644
--- a/src/main/java/net/minecraft/server/ServerConnectionChannel.java
+++ b/src/main/java/net/minecraft/server/ServerConnectionChannel.java
@@ -1,15 +1,26 @@
 package net.minecraft.server;
 
+import com.google.common.util.concurrent.ThreadFactoryBuilder; // Spigot
 import net.minecraft.util.io.netty.channel.Channel;
 import net.minecraft.util.io.netty.channel.ChannelException;
 import net.minecraft.util.io.netty.channel.ChannelInitializer;
 import net.minecraft.util.io.netty.channel.ChannelOption;
 import net.minecraft.util.io.netty.handler.timeout.ReadTimeoutHandler;
+// Spigot Start
+import net.minecraft.util.io.netty.util.concurrent.DefaultEventExecutorGroup;
+import net.minecraft.util.io.netty.util.concurrent.EventExecutorGroup;
+import org.spigotmc.ChunkCompressor;
+import org.spigotmc.SpigotConfig;
+// Spigot End
 
 class ServerConnectionChannel extends ChannelInitializer {
 
     final ServerConnection a;
-
+    // Spigot Start
+    private static final EventExecutorGroup threadPool = new DefaultEventExecutorGroup( SpigotConfig.compressionThreads, new ThreadFactoryBuilder().setNameFormat( "Chunk Compressor #%d" ).setDaemon( true ).build() );
+    private static final ChunkCompressor chunkCompressor = new ChunkCompressor();
+    // Spigot End
+    
     ServerConnectionChannel(ServerConnection serverconnection) {
         this.a = serverconnection;
     }
@@ -27,7 +38,8 @@ class ServerConnectionChannel extends ChannelInitializer {
             ;
         }
 
-        channel.pipeline().addLast("timeout", new ReadTimeoutHandler(30)).addLast("legacy_query", new LegacyPingHandler(this.a)).addLast("splitter", new PacketSplitter()).addLast("decoder", new PacketDecoder()).addLast("prepender", new PacketPrepender()).addLast("encoder", new PacketEncoder());
+        channel.pipeline().addLast("timeout", new ReadTimeoutHandler(30)).addLast("legacy_query", new LegacyPingHandler(this.a)).addLast("splitter", new PacketSplitter()).addLast("decoder", new PacketDecoder()).addLast("prepender", new PacketPrepender()).addLast("encoder", new PacketEncoder())
+                .addLast( threadPool, "compressor", chunkCompressor ); // Spigot
         NetworkManager networkmanager = new NetworkManager(false);
 
         ServerConnection.a(this.a).add(networkmanager);
diff --git a/src/main/java/org/spigotmc/ChunkCompressor.java b/src/main/java/org/spigotmc/ChunkCompressor.java
new file mode 100644
index 0000000..023900f
--- /dev/null
+++ b/src/main/java/org/spigotmc/ChunkCompressor.java
@@ -0,0 +1,65 @@
+package org.spigotmc;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import net.minecraft.server.PacketPlayOutMapChunkBulk;
+import net.minecraft.util.io.netty.channel.ChannelHandler;
+import net.minecraft.util.io.netty.channel.ChannelHandlerContext;
+import net.minecraft.util.io.netty.channel.ChannelOutboundHandlerAdapter;
+import net.minecraft.util.io.netty.channel.ChannelPromise;
+
+@ChannelHandler.Sharable
+public class ChunkCompressor extends ChannelOutboundHandlerAdapter
+{
+
+    private final LinkedHashMap<Integer, byte[]> cache = new LinkedHashMap<Integer, byte[]>( 16, 0.75f, true ); // Defaults, order by access
+    private volatile int cacheSize;
+
+    @Override
+    public synchronized void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception
+    {
+        long start = System.currentTimeMillis();
+        boolean cached = false;
+        if ( msg instanceof PacketPlayOutMapChunkBulk )
+        {
+            PacketPlayOutMapChunkBulk chunk = (PacketPlayOutMapChunkBulk) msg;
+            // Here we assign a hash to the chunk based on the array of its coordinates: x1, z1, x2, z2, x3, z3 etc etc
+            int[] series = new int[ chunk.a.length * 2 ];
+            int pos = 0; // TODO: Can this be determined mathematically?
+            for ( int i = 0; i < chunk.a.length; i++ )
+            {
+                series[pos++] = chunk.a[i];
+                series[pos++] = chunk.b[i];
+            }
+            int hash = Arrays.hashCode( series );
+
+            byte[] deflated = cache.get( hash );
+            if ( deflated != null )
+            {
+                chunk.buffer = deflated;
+                chunk.size = deflated.length;
+                cached = true;
+            } else
+            {
+                chunk.compress(); // Compress the chunk
+                byte[] buffer = Arrays.copyOf( chunk.buffer, chunk.size ); // Resize the array to correct sizing
+
+                Iterator<Map.Entry<Integer, byte[]>> iter = cache.entrySet().iterator(); // Grab a single iterator reference
+                // Whilst this next entry is too big for us, and we have stuff to remove
+                while ( cacheSize + buffer.length > org.spigotmc.SpigotConfig.chunkCacheBytes && iter.hasNext() )
+                {
+                    Map.Entry<Integer, byte[]> entry = iter.next(); // Grab entry
+                    cacheSize -= entry.getValue().length; // Update size table
+                    iter.remove(); // Remove it alltogether
+                }
+                cacheSize += buffer.length; // Update size table
+                cache.put( hash, buffer ); // Pop the new one in the cache
+            }
+            // System.out.println( "Time: " + ( System.currentTimeMillis() - start ) + " " + cached + " " + cacheSize );
+        }
+
+        super.write( ctx, msg, promise );
+    }
+}
diff --git a/src/main/java/org/spigotmc/SpigotConfig.java b/src/main/java/org/spigotmc/SpigotConfig.java
index 552266b..e6d414a 100755
--- a/src/main/java/org/spigotmc/SpigotConfig.java
+++ b/src/main/java/org/spigotmc/SpigotConfig.java
@@ -266,4 +266,16 @@ public class SpigotConfig
     {
         playerShuffle = getInt( "settings.player-shuffle", 0 );
     }
+
+    public static int compressionThreads;
+    public static int chunkCacheBytes;
+    private static void chunkStuff()
+    {
+        compressionThreads = getInt( "settings.compression-threads", 4 );
+        Bukkit.getLogger().log( Level.INFO, "Using {0} threads for async chunk compression", compressionThreads );
+
+        chunkCacheBytes = getInt( "settings.compressed-chunk-cache", 64 ) << 20;
+        Bukkit.getLogger().log( Level.INFO, "Reserving {0} bytes for compressed chunk cache", chunkCacheBytes );
+
+    }
 }
-- 
1.8.3.2