45 lines
2.2 KiB
Diff
45 lines
2.2 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: IzzelAliz <csh2001331@126.com>
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Date: Tue, 14 Dec 2021 12:43:03 +0800
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Subject: [PATCH] Optimize Util#sequence
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Original method allocates O(n^2) memory on n-size list.
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diff --git a/src/main/java/net/minecraft/Util.java b/src/main/java/net/minecraft/Util.java
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index 9c111d479bbcc101886c12950c97f10941125ae7..34e571b702684673b89103176838dc246ff9b24d 100644
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--- a/src/main/java/net/minecraft/Util.java
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+++ b/src/main/java/net/minecraft/Util.java
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@@ -390,22 +390,18 @@ public class Util {
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return (Strategy<K>) Util.IdentityStrategy.INSTANCE; // Paper - decompile fix
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}
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+ private static final CompletableFuture<?>[] EMPTY_FUTURE = new CompletableFuture[0]; // Paper
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public static <V> CompletableFuture<List<V>> sequence(List<? extends CompletableFuture<? extends V>> futures) {
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- return futures.stream().reduce(CompletableFuture.completedFuture(Lists.newArrayList()), (completableFuture, completableFuture2) -> {
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- return completableFuture2.thenCombine(completableFuture, (object, list) -> {
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- List<V> list2 = Lists.newArrayListWithCapacity(list.size() + 1);
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- list2.addAll(list);
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- list2.add(object);
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- return list2;
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- });
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- }, (completableFuture, completableFuture2) -> {
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- return completableFuture.thenCombine(completableFuture2, (list, list2) -> {
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- List<V> list3 = Lists.newArrayListWithCapacity(list.size() + list2.size());
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- list3.addAll(list);
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- list3.addAll(list2);
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- return list3;
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+ // Paper start - optimize
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+ return CompletableFuture.allOf(futures.toArray(EMPTY_FUTURE))
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+ .thenApply(v -> {
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+ List<V> list = Lists.newArrayListWithCapacity(futures.size());
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+ for (CompletableFuture<? extends V> future : futures) {
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+ list.add(future.join());
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+ }
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+ return list;
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});
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- });
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+ // Paper end
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}
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public static <V> CompletableFuture<List<V>> sequenceFailFast(List<? extends CompletableFuture<? extends V>> futures) {
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