From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Dreeam <61569423+Dreeam-qwq@users.noreply.github.com>
Date: Tue, 2 Jan 2024 21:13:53 -0500
Subject: [PATCH] Faster sequencing of futures for chunk structure gen

Replace `thenApply` with `thenCompose`. Once one task is completed then the next task starts immediately,
to prevent blocking threads while waiting to complete all tasks. But may cause the sequence of future compose disorder.

diff --git a/src/main/java/net/minecraft/Util.java b/src/main/java/net/minecraft/Util.java
index 0bd367235f80c1f0d319a6aa5130d82ad82d895c..688fae80e8dd9bb917a568f25fd8be6d30684185 100644
--- a/src/main/java/net/minecraft/Util.java
+++ b/src/main/java/net/minecraft/Util.java
@@ -452,13 +452,27 @@ public class Util {
         return object;
     }
 
+    // Leaf start - Faster sequencing of futures for chunk structure gen
     public static <V> CompletableFuture<List<V>> sequence(List<? extends CompletableFuture<V>> futures) {
+        return sequence(futures, false);
+    }
+    // Leaf end - Faster sequencing of futures for chunk structure gen
+
+    public static <V> CompletableFuture<List<V>> sequence(List<? extends CompletableFuture<V>> futures, boolean useFaster) {
         if (futures.isEmpty()) {
             return CompletableFuture.completedFuture(List.of());
         } else if (futures.size() == 1) {
             return futures.get(0).thenApply(List::of);
         } else {
             CompletableFuture<Void> completableFuture = CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]));
+            // Leaf start - Faster sequencing of futures for chunk structure gen
+            if (org.dreeam.leaf.config.modules.opt.FasterStructureGenFutureSequencing.enabled && useFaster) {
+                return completableFuture.thenCompose(void_ ->
+                        CompletableFuture.supplyAsync(() ->
+                                futures.stream().map(CompletableFuture::join).toList()));
+            }
+            // Leaf end
+
             return completableFuture.thenApply(void_ -> futures.stream().map(CompletableFuture::join).toList());
         }
     }
diff --git a/src/main/java/net/minecraft/server/ReloadableServerRegistries.java b/src/main/java/net/minecraft/server/ReloadableServerRegistries.java
index 69682d7be64a2163d574de939f5146f5a7a642ef..4aeddef3aac9b20cfa88419ceb4bd1135908d1f0 100644
--- a/src/main/java/net/minecraft/server/ReloadableServerRegistries.java
+++ b/src/main/java/net/minecraft/server/ReloadableServerRegistries.java
@@ -50,7 +50,7 @@ public class ReloadableServerRegistries {
         List<CompletableFuture<WritableRegistry<?>>> list = LootDataType.values()
             .map(type -> scheduleElementParse((LootDataType<?>)type, registryOps, resourceManager, prepareExecutor))
             .toList();
-        CompletableFuture<List<WritableRegistry<?>>> completableFuture = Util.sequence(list);
+        CompletableFuture<List<WritableRegistry<?>>> completableFuture = Util.sequence(list, false); // Leaf - Faster sequencing of futures for chunk structure gen
         return completableFuture.thenApplyAsync(registries -> apply(dynamicRegistries, (List<WritableRegistry<?>>)registries), prepareExecutor);
     }
 
diff --git a/src/main/java/net/minecraft/world/level/chunk/ChunkGeneratorStructureState.java b/src/main/java/net/minecraft/world/level/chunk/ChunkGeneratorStructureState.java
index a6b6e5ea191c0e2cd7a2e4f01b89d8af40a83c1b..713fced29fbd819ee6f151c7f3e462f58a21d5e6 100644
--- a/src/main/java/net/minecraft/world/level/chunk/ChunkGeneratorStructureState.java
+++ b/src/main/java/net/minecraft/world/level/chunk/ChunkGeneratorStructureState.java
@@ -270,7 +270,7 @@ public class ChunkGeneratorStructureState {
                 }
             }
 
-            return Util.sequence(list).thenApply((list1) -> {
+            return Util.sequence(list, true).thenApply((list1) -> { // Leaf - Faster sequencing of futures for chunk structure gen
                 double d2 = (double) stopwatch.stop().elapsed(TimeUnit.MILLISECONDS) / 1000.0D;
 
                 ChunkGeneratorStructureState.LOGGER.debug("Calculation for {} took {}s", structureSetEntry, d2);
diff --git a/src/main/java/org/dreeam/leaf/config/modules/opt/FasterStructureGenFutureSequencing.java b/src/main/java/org/dreeam/leaf/config/modules/opt/FasterStructureGenFutureSequencing.java
new file mode 100644
index 0000000000000000000000000000000000000000..3368baa899cd514f01b3244a4066fb9d13f069b3
--- /dev/null
+++ b/src/main/java/org/dreeam/leaf/config/modules/opt/FasterStructureGenFutureSequencing.java
@@ -0,0 +1,29 @@
+package org.dreeam.leaf.config.modules.opt;
+
+import com.electronwill.nightconfig.core.file.CommentedFileConfig;
+import org.dreeam.leaf.config.ConfigInfo;
+import org.dreeam.leaf.config.EnumConfigCategory;
+import org.dreeam.leaf.config.IConfigModule;
+
+public class FasterStructureGenFutureSequencing implements IConfigModule {
+
+    @Override
+    public EnumConfigCategory getCategory() {
+        return EnumConfigCategory.PERFORMANCE;
+    }
+
+    @Override
+    public String getBaseName() {
+        return "faster_structure_gen_future_sequencing";
+    }
+
+    @ConfigInfo(baseName = "enabled")
+    public static boolean enabled = true;
+
+    @Override
+    public void onLoaded(CommentedFileConfig config) {
+        config.setComment("performance.faster_structure_gen_future_sequencing", """
+                May cause the inconsistent order of future compose tasls.
+                """);
+    }
+}