From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Aikar Date: Tue, 21 Apr 2020 03:51:53 -0400 Subject: [PATCH] Allow multiple callbacks to schedule for Callback Executor ChunkMapDistance polls multiple entries for pendingChunkUpdates Each of these have the potential to move a chunk in and out of "Loaded" state, which will result in multiple callbacks being needed within a single tick of ChunkMapDistance Use an ArrayDeque to store this Queue We make sure to also implement a pattern that is recursion safe too. diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java index 2b4c35d9bd186fd7c3650a7ad791cd67fb64e635..e7c78106aa34d948a77cf72d5716e17d10beae72 100644 --- a/src/main/java/net/minecraft/server/level/ChunkMap.java +++ b/src/main/java/net/minecraft/server/level/ChunkMap.java @@ -178,17 +178,29 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider public final CallbackExecutor callbackExecutor = new CallbackExecutor(); public static final class CallbackExecutor implements java.util.concurrent.Executor, Runnable { - private final java.util.Queue queue = new java.util.ArrayDeque<>(); + // Paper start - replace impl with recursive safe multi entry queue + // it's possible to schedule multiple tasks currently, so it's vital we change this impl + // If we recurse into the executor again, we will append to another queue, ensuring task order consistency + private java.util.Queue queue = new java.util.ArrayDeque<>(); // Paper - remove final @Override public void execute(Runnable runnable) { + if (this.queue == null) { + this.queue = new java.util.ArrayDeque<>(); + } this.queue.add(runnable); } @Override public void run() { + if (this.queue == null) { + return; + } + java.util.Queue queue = this.queue; + this.queue = null; + // Paper end Runnable task; - while ((task = this.queue.poll()) != null) { + while ((task = queue.poll()) != null) { // Paper task.run(); } }