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/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java index 047d6ccdc85363b27f9c7d78c4281fdf4ade1087..f81eeb7e86018d47312170bda1b4b76697943d69 100644 --- a/src/main/java/net/minecraft/server/PlayerChunkMap.java +++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java @@ -87,24 +87,32 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d { public final CallbackExecutor callbackExecutor = new CallbackExecutor(); public static final class CallbackExecutor implements java.util.concurrent.Executor, Runnable { - private Runnable queued; + // 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.ArrayDeque queued = new java.util.ArrayDeque<>(); @Override public void execute(Runnable runnable) { - if (queued != null) { - throw new IllegalStateException("Already queued"); + if (queued == null) { + queued = new java.util.ArrayDeque<>(); } - queued = runnable; + queued.add(runnable); } @Override public void run() { - Runnable task = queued; + if (queued == null) { + return; + } + java.util.ArrayDeque queue = queued; queued = null; - if (task != null) { + Runnable task; + while ((task = queue.pollFirst()) != null) { task.run(); } } + // Paper end }; // CraftBukkit end