made stronghold generation thread safe

src/main/java/gregor0410/lazystronghold/ChunkGeneratorInterface.java

@@ -1,5 +1,10 @@
 package gregor0410.lazystronghold;
 
+import net.minecraft.util.math.ChunkPos;
+
+import java.util.List;
+
 public interface ChunkGeneratorInterface {
     StrongholdGen getStrongholdGen();
+    List<ChunkPos> getStrongholds();
 }

src/main/java/gregor0410/lazystronghold/StrongholdGen.java

@@ -5,11 +5,9 @@
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.world.biome.Biome;
-import net.minecraft.world.biome.Biomes;
 import net.minecraft.world.biome.source.BiomeSource;
 import net.minecraft.world.gen.chunk.ChunkGenerator;
 import net.minecraft.world.gen.chunk.StrongholdConfig;
-import net.minecraft.world.gen.chunk.StructuresConfig;
 import net.minecraft.world.gen.feature.StructureFeature;
 import org.apache.logging.log4j.Level;
 
@@ -19,36 +17,36 @@
 
 public class StrongholdGen implements Runnable {
     private final StrongholdConfig config;
-    private ChunkGenerator generator;
-    private Thread thread;
+    private final Thread thread;
     private Random random;
     private int i;
     private int j;
     private int k;
     private double d;
     private int l;
     private int m;
-    private int n;
-    private BiomeSource biomeSource;
-    private long seed;
+    private int n = 0;
+    private final BiomeSource biomeSource;
+    private final long seed;
     private ArrayList<Biome> list;
+    public List<ChunkPos> strongholds;
 
     public StrongholdGen(ChunkGenerator generator){
-        this.generator = generator;
         this.seed = ((ChunkGeneratorAccess)generator).getField_24748();
-        this.biomeSource = generator.getBiomeSource();
+        this.biomeSource = generator.getBiomeSource().withSeed(seed); //create new biome source instance for thread safety
         this.thread = new Thread(this,"Stronghold thread");
-        this.config = this.generator.getConfig().getStronghold();
+        this.config = generator.getConfig().getStronghold();
+        this.strongholds = ((ChunkGeneratorInterface)generator).getStrongholds();
     }
     public void start(){
         this.thread.start();
     }
     @Override
     public void run() {
         Lazystronghold.log(Level.INFO,"Started stronghold gen thread");
-        while(!generateStronghold());
-        if(((ChunkGeneratorAccess)this.generator).getField_24749().size()!=this.config.getCount()){
-            Lazystronghold.log(Level.ERROR,"Only "+((ChunkGeneratorAccess)this.generator).getField_24749().size() +" strongholds generated!");
+        while(!this.generateStronghold());
+        if(this.strongholds.size()!=this.config.getCount()){
+            Lazystronghold.log(Level.ERROR,"Only "+this.strongholds.size() +" strongholds generated!");
         }else{
             Lazystronghold.log(Level.INFO,"Generated "+this.config.getCount() +" strongholds.");
         }
@@ -79,7 +77,7 @@ private boolean generateStronghold(){
                 o = blockPos.getX() >> 4;
                 p = blockPos.getZ() >> 4;
             }
-            ((ChunkGeneratorAccess)this.generator).getField_24749().add(new ChunkPos(o,p));
+            this.strongholds.add(new ChunkPos(o,p));
             d += Math.PI * 2 / (double)k;
             ++l;
             if (l == k) {

src/main/java/gregor0410/lazystronghold/mixin/ChunkGeneratorMixin.java

@@ -2,22 +2,29 @@
 
 import gregor0410.lazystronghold.ChunkGeneratorInterface;
 import gregor0410.lazystronghold.StrongholdGen;
-import net.minecraft.world.biome.source.BiomeSource;
+import net.minecraft.util.math.ChunkPos;
 import net.minecraft.world.gen.chunk.ChunkGenerator;
 import net.minecraft.world.gen.chunk.StructuresConfig;
-import net.minecraft.world.gen.feature.StructureFeature;
+import org.objectweb.asm.Opcodes;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyVariable;
+import org.spongepowered.asm.mixin.injection.Redirect;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
 @Mixin(ChunkGenerator.class)
 public class ChunkGeneratorMixin implements ChunkGeneratorInterface {
-    @Shadow @Final protected BiomeSource biomeSource;
     @Shadow @Final private StructuresConfig config;
     private StrongholdGen strongholdGen = null;
+    private final List<ChunkPos> strongholds = new CopyOnWriteArrayList<>();
+
 
     @Inject(method="method_28509",at=@At("HEAD"),cancellable = true)
     private void genStrongholds(CallbackInfo ci){
@@ -28,9 +35,21 @@ private void genStrongholds(CallbackInfo ci){
         }
         ci.cancel();
     }
-
+    @ModifyVariable(at=@At("STORE"),ordinal = 0,method="locateStructure(Lnet/minecraft/server/world/ServerWorld;Lnet/minecraft/world/gen/feature/StructureFeature;Lnet/minecraft/util/math/BlockPos;IZ)Lnet/minecraft/util/math/BlockPos;")
+    private Iterator<ChunkPos> getStrongholdIterator(Iterator<ChunkPos> i){
+        return this.strongholds.iterator();
+    }
+    @Redirect(method="method_28507(Lnet/minecraft/util/math/ChunkPos;)Z",at=@At(value="FIELD",target="Lnet/minecraft/world/gen/chunk/ChunkGenerator;field_24749:Ljava/util/List;",opcode = Opcodes.GETFIELD))
+    private List<ChunkPos> method_28507_redirect(ChunkGenerator generator){
+        return this.strongholds;
+    }
     @Override
     public StrongholdGen getStrongholdGen() {
         return this.strongholdGen;
     }
+
+    @Override
+    public List<ChunkPos> getStrongholds() {
+        return this.strongholds;
+    }
 }

src/main/java/gregor0410/lazystronghold/mixin/MinecraftServerMixin.java

@@ -1,15 +1,12 @@
 package gregor0410.lazystronghold.mixin;
 
 import gregor0410.lazystronghold.ChunkGeneratorInterface;
-import gregor0410.lazystronghold.Lazystronghold;
 import gregor0410.lazystronghold.StrongholdGen;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.world.ServerWorld;
 import net.minecraft.util.math.ChunkPos;
 import net.minecraft.util.registry.RegistryKey;
-import net.minecraft.world.SaveProperties;
 import net.minecraft.world.World;
-import org.apache.logging.log4j.Level;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
@@ -23,12 +20,12 @@
 public class MinecraftServerMixin {
     @Shadow @Final private Map<RegistryKey<World>, ServerWorld> worlds;
 
-    @Shadow @Final protected SaveProperties saveProperties;
-
     @Inject(method="Lnet/minecraft/server/MinecraftServer;prepareStartRegion(Lnet/minecraft/server/WorldGenerationProgressListener;)V",at=@At("TAIL"))
     private void prepareStartRegion(CallbackInfo ci){
         this.worlds.get(World.OVERWORLD).getChunkManager().getChunkGenerator().method_28507(new ChunkPos(0,0));
         StrongholdGen strongholdGen = ((ChunkGeneratorInterface)this.worlds.get(World.OVERWORLD).getChunkManager().getChunkGenerator()).getStrongholdGen();
-        strongholdGen.start();
+        if(strongholdGen!=null) {
+            strongholdGen.start();
+        }
     }
 }