From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Thu, 20 May 2021 07:02:22 -0700
Subject: [PATCH] Fix and optimise world force upgrading

The WorldUpgrader class was incorrectly modified by
CB. It will store an IChunkLoader instance for all
dimension types in the world, but obviously with how
CB shifts around worlds only one dimension type exists
per world. But this would be OK if CB did this
change correctly. All IChunkLoader instances
will point to the same regionfiles. And all
IChunkLoader instances are going to be read from.

This problem hasn't really been reported because
it relies on the persistent legacy data to be converted
as well to cause corruption. Why? Because the legacy
data is also shared, it will result in different
outputs from conversion (as once conversion for legacy
persistent data takes place, it is REMOVED - so the next
convert will _not_ have the data). Which means different
sizes on disk. Which means different regionfile sector
allocations. Which means there are 3 different possible
regionfile sector allocations in memory, and none of them
are going to be correct.

I've fixed this by writing a world upgrader suited to
CB's changes to world folder format. It was brain dead
easy to add threading, so I did.

== AT ==
public net.minecraft.util.worldupdate.WorldUpgrader REGEX

diff --git a/src/main/java/io/papermc/paper/world/ThreadedWorldUpgrader.java b/src/main/java/io/papermc/paper/world/ThreadedWorldUpgrader.java
new file mode 100644
index 0000000000000000000000000000000000000000..95cac7edae8ac64811fc6a2f6b97dd4a0fceb0b0
--- /dev/null
+++ b/src/main/java/io/papermc/paper/world/ThreadedWorldUpgrader.java
@@ -0,0 +1,209 @@
+package io.papermc.paper.world;
+
+import com.mojang.datafixers.DataFixer;
+import com.mojang.serialization.Codec;
+import net.minecraft.SharedConstants;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.util.worldupdate.WorldUpgrader;
+import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.chunk.ChunkGenerator;
+import net.minecraft.world.level.chunk.storage.ChunkStorage;
+import net.minecraft.world.level.chunk.storage.RegionFileStorage;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.dimension.LevelStem;
+import net.minecraft.world.level.levelgen.WorldGenSettings;
+import net.minecraft.world.level.storage.DimensionDataStorage;
+import net.minecraft.world.level.storage.LevelStorageSource;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import java.io.File;
+import java.io.IOException;
+import java.text.DecimalFormat;
+import java.util.Optional;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Supplier;
+
+public class ThreadedWorldUpgrader {
+
+    private static final Logger LOGGER = LogManager.getLogger();
+
+    private final ResourceKey<LevelStem> dimensionType;
+    private final String worldName;
+    private final File worldDir;
+    private final ExecutorService threadPool;
+    private final DataFixer dataFixer;
+    private final Optional<ResourceKey<Codec<? extends ChunkGenerator>>> generatorKey;
+    private final boolean removeCaches;
+
+    public ThreadedWorldUpgrader(final ResourceKey<LevelStem> dimensionType, final String worldName, final File worldDir, final int threads,
+                                 final DataFixer dataFixer, final Optional<ResourceKey<Codec<? extends ChunkGenerator>>> generatorKey, final boolean removeCaches) {
+        this.dimensionType = dimensionType;
+        this.worldName = worldName;
+        this.worldDir = worldDir;
+        this.threadPool = Executors.newFixedThreadPool(Math.max(1, threads), new ThreadFactory() {
+            private final AtomicInteger threadCounter = new AtomicInteger();
+
+            @Override
+            public Thread newThread(final Runnable run) {
+                final Thread ret = new Thread(run);
+
+                ret.setName("World upgrader thread for world " + ThreadedWorldUpgrader.this.worldName + " #" + this.threadCounter.getAndIncrement());
+                ret.setUncaughtExceptionHandler((thread, throwable) -> {
+                    LOGGER.fatal("Error upgrading world", throwable);
+                });
+
+                return ret;
+            }
+        });
+        this.dataFixer = dataFixer;
+        this.generatorKey = generatorKey;
+        this.removeCaches = removeCaches;
+    }
+
+    public void convert() {
+        final File worldFolder = LevelStorageSource.getStorageFolder(this.worldDir.toPath(), this.dimensionType).toFile();
+        final DimensionDataStorage worldPersistentData = new DimensionDataStorage(new File(worldFolder, "data"), this.dataFixer);
+
+        final File regionFolder = new File(worldFolder, "region");
+
+        LOGGER.info("Force upgrading " + this.worldName);
+        LOGGER.info("Counting regionfiles for " + this.worldName);
+        final File[] regionFiles = regionFolder.listFiles((final File dir, final String name) -> {
+            return WorldUpgrader.REGEX.matcher(name).matches();
+        });
+        if (regionFiles == null) {
+            LOGGER.info("Found no regionfiles to convert for world " + this.worldName);
+            return;
+        }
+        LOGGER.info("Found " + regionFiles.length + " regionfiles to convert");
+        LOGGER.info("Starting conversion now for world " + this.worldName);
+
+        final WorldInfo info = new WorldInfo(() -> worldPersistentData,
+                new ChunkStorage(regionFolder.toPath(), this.dataFixer, false), this.removeCaches, this.dimensionType, this.generatorKey);
+
+        long expectedChunks = (long)regionFiles.length * (32L * 32L);
+
+        for (final File regionFile : regionFiles) {
+            final ChunkPos regionPos = RegionFileStorage.getRegionFileCoordinates(regionFile.toPath());
+            if (regionPos == null) {
+                expectedChunks -= (32L * 32L);
+                continue;
+            }
+
+            this.threadPool.execute(new ConvertTask(info, regionPos.x >> 5, regionPos.z >> 5));
+        }
+        this.threadPool.shutdown();
+
+        final DecimalFormat format = new DecimalFormat("#0.00");
+
+        final long start = System.nanoTime();
+
+        while (!this.threadPool.isTerminated()) {
+            final long current = info.convertedChunks.get();
+
+            LOGGER.info("{}% completed ({} / {} chunks)...", format.format((double)current / (double)expectedChunks * 100.0), current, expectedChunks);
+
+            try {
+                Thread.sleep(1000L);
+            } catch (final InterruptedException ignore) {}
+        }
+
+        final long end = System.nanoTime();
+
+        try {
+            info.loader.close();
+        } catch (final IOException ex) {
+            LOGGER.fatal("Failed to close chunk loader", ex);
+        }
+        LOGGER.info("Completed conversion. Took {}s, {} out of {} chunks needed to be converted/modified ({}%)",
+                (int)Math.ceil((end - start) * 1.0e-9), info.modifiedChunks.get(), expectedChunks, format.format((double)info.modifiedChunks.get() / (double)expectedChunks * 100.0));
+    }
+
+    private static final class WorldInfo {
+
+        public final Supplier<DimensionDataStorage> persistentDataSupplier;
+        public final ChunkStorage loader;
+        public final boolean removeCaches;
+        public final ResourceKey<LevelStem> worldKey;
+        public final Optional<ResourceKey<Codec<? extends ChunkGenerator>>> generatorKey;
+        public final AtomicLong convertedChunks = new AtomicLong();
+        public final AtomicLong modifiedChunks = new AtomicLong();
+
+        private WorldInfo(final Supplier<DimensionDataStorage> persistentDataSupplier, final ChunkStorage loader, final boolean removeCaches,
+                          final ResourceKey<LevelStem> worldKey, Optional<ResourceKey<Codec<? extends ChunkGenerator>>> generatorKey) {
+            this.persistentDataSupplier = persistentDataSupplier;
+            this.loader = loader;
+            this.removeCaches = removeCaches;
+            this.worldKey = worldKey;
+            this.generatorKey = generatorKey;
+        }
+    }
+
+    private static final class ConvertTask implements Runnable {
+
+        private final WorldInfo worldInfo;
+        private final int regionX;
+        private final int regionZ;
+
+        public ConvertTask(final WorldInfo worldInfo, final int regionX, final int regionZ) {
+            this.worldInfo = worldInfo;
+            this.regionX = regionX;
+            this.regionZ = regionZ;
+        }
+
+        @Override
+        public void run() {
+            final int regionCX = this.regionX << 5;
+            final int regionCZ = this.regionZ << 5;
+
+            final Supplier<DimensionDataStorage> persistentDataSupplier = this.worldInfo.persistentDataSupplier;
+            final ChunkStorage loader = this.worldInfo.loader;
+            final boolean removeCaches = this.worldInfo.removeCaches;
+            final ResourceKey<LevelStem> worldKey = this.worldInfo.worldKey;
+
+            for (int cz = regionCZ; cz < (regionCZ + 32); ++cz) {
+                for (int cx = regionCX; cx < (regionCX + 32); ++cx) {
+                    final ChunkPos chunkPos = new ChunkPos(cx, cz);
+                    try {
+                        // no need to check the coordinate of the chunk, the regionfilecache does that for us
+
+                        CompoundTag chunkNBT = (loader.read(chunkPos).join()).orElse(null);
+
+                        if (chunkNBT == null) {
+                            continue;
+                        }
+
+                        final int versionBefore = ChunkStorage.getVersion(chunkNBT);
+
+                        chunkNBT = loader.upgradeChunkTag(worldKey, persistentDataSupplier, chunkNBT, this.worldInfo.generatorKey, chunkPos, null);
+
+                        boolean modified = versionBefore < SharedConstants.getCurrentVersion().getWorldVersion();
+
+                        if (removeCaches) {
+                            final CompoundTag level = chunkNBT.getCompound("Level");
+                            modified |= level.contains("Heightmaps");
+                            level.remove("Heightmaps");
+                            modified |= level.contains("isLightOn");
+                            level.remove("isLightOn");
+                        }
+
+                        if (modified) {
+                            this.worldInfo.modifiedChunks.getAndIncrement();
+                            loader.write(chunkPos, chunkNBT);
+                        }
+                    } catch (final Exception ex) {
+                        LOGGER.error("Error upgrading chunk {}", chunkPos, ex);
+                    } finally {
+                        this.worldInfo.convertedChunks.getAndIncrement();
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/src/main/java/net/minecraft/server/Main.java b/src/main/java/net/minecraft/server/Main.java
index 2dba2853764ca1cff114d3130672fbd596604ea3..6a5698f05a5f839e643e747c21834aacb90feec8 100644
--- a/src/main/java/net/minecraft/server/Main.java
+++ b/src/main/java/net/minecraft/server/Main.java
@@ -15,6 +15,7 @@ import java.nio.file.Paths;
 import java.util.Optional;
 import java.util.UUID;
 import java.util.function.BooleanSupplier;
+import io.papermc.paper.world.ThreadedWorldUpgrader;
 import joptsimple.NonOptionArgumentSpec;
 import joptsimple.OptionParser;
 import joptsimple.OptionSet;
@@ -329,6 +330,15 @@ public class Main {
         return new WorldLoader.InitConfig(worldloader_d, Commands.CommandSelection.DEDICATED, serverPropertiesHandler.functionPermissionLevel);
     }
 
+    // Paper start - fix and optimise world upgrading
+    public static void convertWorldButItWorks(net.minecraft.resources.ResourceKey<net.minecraft.world.level.dimension.LevelStem> dimensionType, net.minecraft.world.level.storage.LevelStorageSource.LevelStorageAccess worldSession,
+                                              DataFixer dataFixer, Optional<net.minecraft.resources.ResourceKey<com.mojang.serialization.Codec<? extends net.minecraft.world.level.chunk.ChunkGenerator>>> generatorKey, boolean removeCaches) {
+        int threads = Runtime.getRuntime().availableProcessors() * 3 / 8;
+        final ThreadedWorldUpgrader worldUpgrader = new ThreadedWorldUpgrader(dimensionType, worldSession.getLevelId(), worldSession.levelDirectory.path().toFile(), threads, dataFixer, generatorKey, removeCaches);
+        worldUpgrader.convert();
+    }
+    // Paper end - fix and optimise world upgrading
+
     public static void forceUpgrade(LevelStorageSource.LevelStorageAccess session, DataFixer dataFixer, boolean eraseCache, BooleanSupplier continueCheck, Registry<LevelStem> dimensionOptionsRegistry) {
         Main.LOGGER.info("Forcing world upgrade! {}", session.getLevelId()); // CraftBukkit
         WorldUpgrader worldupgrader = new WorldUpgrader(session, dataFixer, dimensionOptionsRegistry, eraseCache);
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index d5cd8d540438638268cc26e2fc9be8415950ee22..13f8b4699c5b3a99715fada2d774469fb5c17363 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -551,11 +551,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
                 worlddata = new PrimaryLevelData(worldsettings, worldoptions, worlddimensions_b.specialWorldProperty(), lifecycle);
             }
             worlddata.checkName(name); // CraftBukkit - Migration did not rewrite the level.dat; This forces 1.8 to take the last loaded world as respawn (in this case the end)
-            if (this.options.has("forceUpgrade")) {
-                net.minecraft.server.Main.forceUpgrade(worldSession, DataFixers.getDataFixer(), this.options.has("eraseCache"), () -> {
-                    return true;
-                }, iregistry);
-            }
+            // Paper - move down
 
             PrimaryLevelData iworlddataserver = worlddata;
             boolean flag = worlddata.isDebugWorld();
@@ -570,6 +566,13 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
                 biomeProvider = gen.getDefaultBiomeProvider(worldInfo);
             }
 
+            // Paper start - fix and optimise world upgrading
+            if (options.has("forceUpgrade")) {
+                net.minecraft.server.Main.convertWorldButItWorks(
+                    dimensionKey, worldSession, DataFixers.getDataFixer(), worlddimension.generator().getTypeNameForDataFixer(), options.has("eraseCache")
+                );
+            }
+            // Paper end - fix and optimise world upgrading
             ResourceKey<Level> worldKey = ResourceKey.create(Registries.DIMENSION, dimensionKey.location());
 
             if (dimensionKey == LevelStem.OVERWORLD) {
diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index 7ed5f86f66b49d33952b2cb3dd5ea438284fcbd4..982dc85ea66bf111a01a62df43696ca550e1294d 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -181,6 +181,15 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
     public final Map<Explosion.CacheKey, Float> explosionDensityCache = new HashMap<>(); // Paper - Optimize explosions
     public java.util.ArrayDeque<net.minecraft.world.level.block.RedstoneTorchBlock.Toggle> redstoneUpdateInfos; // Paper - Move from Map in BlockRedstoneTorch to here
 
+    // Paper start - fix and optimise world upgrading
+    // copied from below
+    public static ResourceKey<DimensionType> getDimensionKey(DimensionType manager) {
+        return ((org.bukkit.craftbukkit.CraftServer)org.bukkit.Bukkit.getServer()).getHandle().getServer().registryAccess().registryOrThrow(net.minecraft.core.registries.Registries.DIMENSION_TYPE).getResourceKey(manager).orElseThrow(() -> {
+            return new IllegalStateException("Unregistered dimension type: " + manager);
+        });
+    }
+    // Paper end - fix and optimise world upgrading
+
     public CraftWorld getWorld() {
         return this.world;
     }
diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java b/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java
index b294ef87fb93e7f4651dc04128124f297575860d..65fd57609e45ccd49ebfc1ba80d25243da13ab6e 100644
--- a/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java
+++ b/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java
@@ -32,6 +32,28 @@ public class RegionFileStorage implements AutoCloseable {
     }
 
     // Paper start
+    public static @Nullable ChunkPos getRegionFileCoordinates(Path file) {
+        String fileName = file.getFileName().toString();
+        if (!fileName.startsWith("r.") || !fileName.endsWith(".mca")) {
+            return null;
+        }
+
+        String[] split = fileName.split("\\.");
+
+        if (split.length != 4) {
+            return null;
+        }
+
+        try {
+            int x = Integer.parseInt(split[1]);
+            int z = Integer.parseInt(split[2]);
+
+            return new ChunkPos(x << 5, z << 5);
+        } catch (NumberFormatException ex) {
+            return null;
+        }
+    }
+
     public synchronized RegionFile getRegionFileIfLoaded(ChunkPos chunkcoordintpair) {
         return this.regionCache.getAndMoveToFirst(ChunkPos.asLong(chunkcoordintpair.getRegionX(), chunkcoordintpair.getRegionZ()));
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index f28e588489088e948e70f87951e07728e600f737..e8f7b418b942a6a36e615dbcaf9bb18257c34ee4 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -1232,12 +1232,7 @@ public final class CraftServer implements Server {
         worlddata.customDimensions = iregistry;
         worlddata.checkName(name);
         worlddata.setModdedInfo(this.console.getServerModName(), this.console.getModdedStatus().shouldReportAsModified());
-
-        if (console.options.has("forceUpgrade")) {
-            net.minecraft.server.Main.forceUpgrade(worldSession, DataFixers.getDataFixer(), console.options.has("eraseCache"), () -> {
-                return true;
-            }, iregistry);
-        }
+        // Paper - move down
 
         long j = BiomeManager.obfuscateSeed(creator.seed());
         List<CustomSpawner> list = ImmutableList.of(new PhantomSpawner(), new PatrolSpawner(), new CatSpawner(), new VillageSiege(), new WanderingTraderSpawner(worlddata));
@@ -1248,6 +1243,13 @@ public final class CraftServer implements Server {
             biomeProvider = generator.getDefaultBiomeProvider(worldInfo);
         }
 
+        // Paper start - fix and optimise world upgrading
+        if (console.options.has("forceUpgrade")) {
+            net.minecraft.server.Main.convertWorldButItWorks(
+                actualDimension,  worldSession, DataFixers.getDataFixer(), worlddimension.generator().getTypeNameForDataFixer(), console.options.has("eraseCache")
+            );
+        }
+        // Paper end - fix and optimise world upgrading
         ResourceKey<net.minecraft.world.level.Level> worldKey;
         String levelName = this.getServer().getProperties().levelName;
         if (name.equals(levelName + "_nether")) {
