Paper/Spigot-Server-Patches/0321-Provide-option-to-use-a-versioned-world-folder-for-t.patch

From b33d52f15d20e9c6ba4457eb799b67e32792e595 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 29 Jul 2018 15:48:50 -0400
Subject: [PATCH] Provide option to use a versioned world folder for testing

This should not ever be used in production!!

This setting is intended for testing so you can try out converting your world
without actually modifying the world files.

This will add some additional overhead to your world, but you're
just testing anyways so that's not a big deal :)

Will store in a folder named after the current version.

PlayerData and Data folders are copied on server start, so there
may be some delay there, but region files are only copied on demand.

This is highly experiemental so backup your world before relying on this to not modify it

diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 5a17ce3d22..f7ece47ed9 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -13,6 +13,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
+import java.util.logging.Logger;
 import java.util.regex.Pattern;
 
 import com.google.common.collect.Lists;
@@ -303,4 +304,27 @@ public class PaperConfig {
             Bukkit.getLogger().log(Level.INFO, "Using Aikar's Alternative Luck Formula to apply Luck attribute to all loot pool calculations. See https://luckformula.emc.gs");
         }
     }
+
+    public static boolean useVersionedWorld = false;
+    private static void useVersionedWorld() {
+        useVersionedWorld = getBoolean("settings.use-versioned-world", false);
+        if (useVersionedWorld) {
+            Logger logger = Bukkit.getLogger();
+            String ver = MinecraftServer.getServer().getVersion();
+            logger.log(Level.INFO, "******************************************************");
+            logger.log(Level.INFO, "*** Using a versioned world folder. Your world will be saved");
+            logger.log(Level.INFO, "*** to into the " + ver + " folder, but copied from your current world.");
+            logger.log(Level.INFO, "*** ");
+            logger.log(Level.INFO, "*** This setting should not be used in your real world!!!");
+            logger.log(Level.INFO, "*** If you want to retain the new world, you need to move ");
+            logger.log(Level.INFO, "*** the folders out of the " + ver + " folder and overwrite existing");
+            logger.log(Level.INFO, "*** ");
+            logger.log(Level.INFO, "*** Deleting the " + ver + " folder will cause it to recreate again");
+            logger.log(Level.INFO, "*** from your unversioned world files.");
+            logger.log(Level.INFO, "*** ");
+            logger.log(Level.INFO, "*** You should backup your original world files incase something goes");
+            logger.log(Level.INFO, "*** wrong with this system! This is not a backup system.");
+            logger.log(Level.INFO, "******************************************************");
+        }
+    }
 }
diff --git a/src/main/java/net/minecraft/server/ChunkRegionLoader.java b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
index bd52bf6561..54840851ba 100644
--- a/src/main/java/net/minecraft/server/ChunkRegionLoader.java
+++ b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
@@ -55,8 +55,56 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver {
     private PersistentStructureLegacy e;
     // private boolean f; // CraftBukkit
     private static final double SAVE_QUEUE_TARGET_SIZE = 625; // Spigot
+    // Paper start - support saving to an alternate directory
+    private final File templateWorld;
+    private final File actualWorld;
+    private final boolean useAltWorld;
+
+    private boolean chunkExists0(int x, int z) {
+        copyIfNeeded(x, z);
+        return RegionFileCache.chunkExists(this.actualWorld, x, z);
+    }
+    private synchronized void copyIfNeeded(int x, int z) {
+        if (!useAltWorld) {
+            return;
+        }
+        if (RegionFileCache.hasRegionFile(this.actualWorld, x, z)) {
+            return;
+        }
+        File actual = RegionFileCache.getRegionFileName(this.actualWorld, x, z);
+        File template = RegionFileCache.getRegionFileName(this.templateWorld, x, z);
+        if (!actual.exists() && template.exists()) {
+            try {
+                //a.info("Copying" + template + " to " + actual);
+                java.nio.file.Files.copy(template.toPath(), actual.toPath(), java.nio.file.StandardCopyOption.COPY_ATTRIBUTES);
+            } catch (IOException e1) {
+                LogManager.getLogger().error("Error copying " + template + " to " + actual, e1);
+                MinecraftServer.getServer().safeShutdown();
+                org.spigotmc.SneakyThrow.sneaky(e1);
+            }
+        }
 
+    }
     public ChunkRegionLoader(File file, DataFixer datafixer) {
+        // Paper
+        this.actualWorld = file;
+        if (com.destroystokyo.paper.PaperConfig.useVersionedWorld) {
+            this.useAltWorld = true;
+            String name = file.getName();
+            File container = file.getParentFile().getParentFile();
+            if (name.equals("DIM-1") || name.equals("DIM1")) {
+                container = container.getParentFile();
+            }
+            this.templateWorld = new File(container, name);
+            File region = new File(file, "region");
+            if (!region.exists()) {
+                region.mkdirs();
+            }
+        } else {
+            this.useAltWorld = false;
+            this.templateWorld = file;
+        }
+        // Paper end
         this.c = file;
         this.d = datafixer;
     }
@@ -77,7 +125,7 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver {
             }
         }
 
-        if (RegionFileCache.chunkExists(this.c, x, z)) {
+        if (chunkExists0(x, z)) { // Paper
             NBTTagCompound nbt = RegionFileCache.read(this.c, x, z);
             if (nbt != null) {
                 NBTTagCompound level = nbt.getCompound("Level");
@@ -97,6 +145,7 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver {
 
     @Nullable
     private NBTTagCompound a(DimensionManager dimensionmanager, @Nullable PersistentCollection persistentcollection, int i, int j, @Nullable GeneratorAccess generatoraccess) throws IOException {
+        copyIfNeeded(i, j); // Paper
         NBTTagCompound nbttagcompound = RegionFileCache.read(this.c, i, j);
 
         if (nbttagcompound == null) {
@@ -205,7 +254,7 @@ public class ChunkRegionLoader implements IChunkLoader, IAsyncChunkSaver {
         ChunkCoordIntPair chunkcoordintpair = new ChunkCoordIntPair(i, j);
         Supplier<NBTTagCompound> nbttagcompound = this.b.get(chunkcoordintpair); // Spigot
 
-        return nbttagcompound != null ? true : RegionFileCache.chunkExists(this.c, i, j);
+        return nbttagcompound != null ? true : chunkExists0(i, j); // Paper
     }
 
     @Nullable
diff --git a/src/main/java/net/minecraft/server/RegionFileCache.java b/src/main/java/net/minecraft/server/RegionFileCache.java
index 609d6c3550..f1fa7c7177 100644
--- a/src/main/java/net/minecraft/server/RegionFileCache.java
+++ b/src/main/java/net/minecraft/server/RegionFileCache.java
@@ -74,6 +74,13 @@ public class RegionFileCache {
             itr.remove();
         }
     }
+    public static synchronized File getRegionFileName(File file, int i, int j) {
+        File file1 = new File(file, "region");
+        return new File(file1, "r." + (i >> 5) + "." + (j >> 5) + ".mca");
+    }
+    public static synchronized boolean hasRegionFile(File file, int i, int j) {
+        return RegionFileCache.a.containsKey(getRegionFileName(file, i, j));
+    }
     // Paper End
 
     public static synchronized void a() {
diff --git a/src/main/java/net/minecraft/server/WorldNBTStorage.java b/src/main/java/net/minecraft/server/WorldNBTStorage.java
index 9a243010d0..3fabbe94f9 100644
--- a/src/main/java/net/minecraft/server/WorldNBTStorage.java
+++ b/src/main/java/net/minecraft/server/WorldNBTStorage.java
@@ -33,6 +33,58 @@ public class WorldNBTStorage implements IDataManager, IPlayerFileData {
 
     public WorldNBTStorage(File file, String s, @Nullable MinecraftServer minecraftserver, DataFixer datafixer) {
         this.a = datafixer;
+        // Paper start
+        if (com.destroystokyo.paper.PaperConfig.useVersionedWorld) {
+            File origBaseDir = new File(file, s);
+            final String currentVersion = MinecraftServer.getServer().getVersion();
+            file = new File(file, currentVersion);
+            File baseDir = new File(file, s);
+
+            if (!baseDir.exists() && origBaseDir.exists() && !baseDir.mkdirs()) {
+                LogManager.getLogger().error("Could not create world directory for " + file);
+                System.exit(1);
+            }
+
+            try {
+                boolean printedHeader = false;
+                String[] dirs  = {"advancements", "data", "datapacks", "playerdata", "stats"};
+                for (String dir : dirs) {
+                    File origPlayerData = new File(origBaseDir, dir);
+                    File targetPlayerData = new File(baseDir, dir);
+                    if (origPlayerData.exists() && !targetPlayerData.exists()) {
+                        if (!printedHeader) {
+                            LogManager.getLogger().info("**** VERSIONED WORLD - Copying files");
+                            printedHeader = true;
+                        }
+                        LogManager.getLogger().info("- Copying: " + dir);
+                        org.apache.commons.io.FileUtils.copyDirectory(origPlayerData, targetPlayerData);
+                    }
+                }
+
+                String[] files = {"level.dat", "level.dat_old", "session.lock", "uid.dat"};
+                for (String fileName : files) {
+                    File origPlayerData = new File(origBaseDir, fileName);
+                    File targetPlayerData = new File(baseDir, fileName);
+                    if (origPlayerData.exists() && !targetPlayerData.exists()) {
+                        if (!printedHeader) {
+                            LogManager.getLogger().info("- Copying files");
+                            printedHeader = true;
+                        }
+                        LogManager.getLogger().info("- Copying: " + fileName);
+                        org.apache.commons.io.FileUtils.copyFile(origPlayerData, targetPlayerData);
+
+                    }
+                }
+                if (printedHeader) {
+                    LogManager.getLogger().info("**** VERSIONED WORLD - Copying DONE");
+                }
+            } catch (IOException e) {
+                LogManager.getLogger().error("Error copying versioned world data for " + origBaseDir + " to " + baseDir, e);
+                org.spigotmc.SneakyThrow.sneaky(e);
+            }
+
+        }
+        // Paper end
         this.baseDir = new File(file, s);
         this.baseDir.mkdirs();
         this.playerDir = new File(this.baseDir, "playerdata");
-- 
2.18.0