Purpur/patches/server/0122-Tuinity-Delay-chunk-unloads.patch

From 3755fa9ef7cb0798f63098b7cc08db5a4bac6b73 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Fri, 25 Oct 2019 02:11:30 -0700
Subject: [PATCH] Tuinity - Delay chunk unloads

Chunk unloads are now delayed by 10s. Specifically, ticket level
reduction is delayed by 10s. This is done to allow players to
teleport and have their pets follow them, as the chunks will no longer
unload or have entity ticking status removed.

It's also targetted to reduce performance regressions when
plugins or edge cases in code do not spam sync loads since chunks
without tickets get unloaded immediately.

Configurable under `delay-chunkunloads-by` in config.
---
 .../java/net/minecraft/server/ChunkMap.java   |  1 +
 .../minecraft/server/ChunkMapDistance.java    | 68 ++++++++++++++++++-
 .../java/net/minecraft/server/Ticket.java     |  6 +-
 .../java/net/minecraft/server/TicketType.java |  1 +
 .../java/net/pl3x/purpur/PurpurConfig.java    |  9 +++
 .../org/bukkit/craftbukkit/CraftWorld.java    |  1 +
 6 files changed, 82 insertions(+), 4 deletions(-)

diff --git a/src/main/java/net/minecraft/server/ChunkMap.java b/src/main/java/net/minecraft/server/ChunkMap.java
index 55f9f4e6e..ac21fdb4c 100644
--- a/src/main/java/net/minecraft/server/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/ChunkMap.java
@@ -68,6 +68,7 @@ public abstract class ChunkMap extends LightEngineGraph {
 
     protected abstract int b(long i);
 
+    public final void update(long coordinate, int level, boolean increaseInLevel) { this.b(coordinate, level, increaseInLevel); } // Purpur - OBFHELPER
     public void b(long i, int j, boolean flag) {
         this.a(ChunkCoordIntPair.a, i, j, flag);
     }
diff --git a/src/main/java/net/minecraft/server/ChunkMapDistance.java b/src/main/java/net/minecraft/server/ChunkMapDistance.java
index 942efe62f..6f710ffa2 100644
--- a/src/main/java/net/minecraft/server/ChunkMapDistance.java
+++ b/src/main/java/net/minecraft/server/ChunkMapDistance.java
@@ -30,7 +30,7 @@ public abstract class ChunkMapDistance {
     private static final int b = 33 + ChunkStatus.a(ChunkStatus.FULL) - 2;
     private final Long2ObjectMap<ObjectSet<EntityPlayer>> c = new Long2ObjectOpenHashMap();
     public final Long2ObjectOpenHashMap<ArraySetSorted<Ticket<?>>> tickets = new Long2ObjectOpenHashMap();
-    private final ChunkMapDistance.a e = new ChunkMapDistance.a();
+    private final ChunkMapDistance.a e = new ChunkMapDistance.a(); final ChunkMapDistance.a getTicketTracker() { return this.e; } // Purpur - OBFHELPER
     public static final int MOB_SPAWN_RANGE = 8; //private final ChunkMapDistance.b f = new ChunkMapDistance.b(8); // Paper - no longer used
     private final ChunkMapDistance.c g = new ChunkMapDistance.c(33);
     private final java.util.Queue<PlayerChunk> pendingChunkUpdates = new java.util.LinkedList<>(); // PAIL pendingChunkUpdates // Paper - use a queue
@@ -42,6 +42,46 @@ public abstract class ChunkMapDistance {
     private long currentTick;
 
     PlayerChunkMap chunkMap; // Paper
+    // Purpur start
+    private long nextUnloadId;
+    private final Long2ObjectOpenHashMap<Ticket<Long>> delayedChunks = new Long2ObjectOpenHashMap<>();
+    public final void removeTickets(long chunk, TicketType<?> type) {
+        ArraySetSorted<Ticket<?>> tickets = this.tickets.get(chunk);
+        if (tickets == null) {
+            return;
+        }
+        if (type == TicketType.DELAYED_UNLOAD) {
+            this.delayedChunks.remove(chunk);
+        }
+        boolean changed = tickets.removeIf((Ticket<?> ticket) -> {
+            return ticket.getTicketType() == type;
+        });
+        if (changed) {
+            this.getTicketTracker().update(chunk, getLowestTicketLevel(tickets), false);
+        }
+    }
+
+    private final java.util.function.LongFunction<Ticket<Long>> computeFuntion = (long key) -> {
+        Ticket<Long> ret = new Ticket<>(TicketType.DELAYED_UNLOAD, -1, ++ChunkMapDistance.this.nextUnloadId);
+        ret.isCached = true;
+        return ret;
+    };
+
+    private void computeDelayedTicketFor(long chunk, int removedLevel, ArraySetSorted<Ticket<?>> tickets) {
+        int lowestLevel = getLowestTicketLevel(tickets);
+        if (removedLevel > lowestLevel) {
+            return;
+        }
+        final Ticket<Long> ticket = this.delayedChunks.computeIfAbsent(chunk, this.computeFuntion);
+        if (ticket.getTicketLevel() != -1) {
+            // since we modify data used in sorting, we need to remove before
+            tickets.remove(ticket);
+        }
+        ticket.setCreationTick(this.currentTick);
+        ticket.setTicketLevel(removedLevel);
+        tickets.add(ticket); // re-add with new expire time and ticket level
+    }
+    // Purpur end
 
     protected ChunkMapDistance(Executor executor, Executor executor1) {
         executor1.getClass();
@@ -58,12 +98,30 @@ public abstract class ChunkMapDistance {
         ++this.currentTick;
         ObjectIterator objectiterator = this.tickets.long2ObjectEntrySet().fastIterator();
 
+        int[] tempLevel = new int[] { PlayerChunkMap.GOLDEN_TICKET + 1 }; // Purpur
         while (objectiterator.hasNext()) {
             Entry<ArraySetSorted<Ticket<?>>> entry = (Entry) objectiterator.next();
 
             if ((entry.getValue()).removeIf((ticket) -> { // CraftBukkit - decompile error
-                return ticket.b(this.currentTick);
+                // Purpur start
+                boolean ret = ticket.isExpired(this.currentTick);
+                if (net.pl3x.purpur.PurpurConfig.delayChunkUnloadsBy <= 0) {
+                    return ret;
+                }
+                if (ret && ticket.getTicketType() != TicketType.DELAYED_UNLOAD && ticket.getTicketLevel() < tempLevel[0]) {
+                    tempLevel[0] = ticket.getTicketLevel();
+                }
+                if (ticket.getTicketType() == TicketType.DELAYED_UNLOAD && ticket.isCached) {
+                    this.delayedChunks.remove(entry.getLongKey(), ticket); // clean up ticket...
+                }
+                return ret;
+                // Purpur end
             })) {
+                // Purpur start
+                if (tempLevel[0] < (PlayerChunkMap.GOLDEN_TICKET + 1)) {
+                    this.computeDelayedTicketFor(entry.getLongKey(), tempLevel[0], entry.getValue());
+                }
+                // Purpur end
                 this.e.b(entry.getLongKey(), a((ArraySetSorted) entry.getValue()), false);
             }
 
@@ -74,6 +132,7 @@ public abstract class ChunkMapDistance {
 
     }
 
+    private static int getLowestTicketLevel(ArraySetSorted<Ticket<?>> arraysetsorted) { return a(arraysetsorted); } // Purpur - OBFHELPER
     private static int a(ArraySetSorted<Ticket<?>> arraysetsorted) {
         return !arraysetsorted.isEmpty() ? ((Ticket) arraysetsorted.b()).b() : PlayerChunkMap.GOLDEN_TICKET + 1;
     }
@@ -156,6 +215,11 @@ public abstract class ChunkMapDistance {
         boolean removed = false; // CraftBukkit
         if (arraysetsorted.remove(ticket)) {
             removed = true; // CraftBukkit
+            // Purpur start
+            if (net.pl3x.purpur.PurpurConfig.delayChunkUnloadsBy > 0 && ticket.getTicketType() != TicketType.DELAYED_UNLOAD) {
+                this.computeDelayedTicketFor(i, ticket.getTicketLevel(), arraysetsorted);
+            }
+            // Purpur end
         }
 
         if (arraysetsorted.isEmpty()) {
diff --git a/src/main/java/net/minecraft/server/Ticket.java b/src/main/java/net/minecraft/server/Ticket.java
index 7a8397815..8aae0b63e 100644
--- a/src/main/java/net/minecraft/server/Ticket.java
+++ b/src/main/java/net/minecraft/server/Ticket.java
@@ -5,9 +5,10 @@ import java.util.Objects;
 public final class Ticket<T> implements Comparable<Ticket<?>> {
 
     private final TicketType<T> a;
-    private final int b;
+    private int b; public final void setTicketLevel(final int value) { this.b = value; } // Purpur - remove final - OBFHELPER
     public final T identifier; public final T getObjectReason() { return this.identifier; } // Paper - OBFHELPER
-    private long d; public final long getCreationTick() { return this.d; } // Paper - OBFHELPER
+    private long d; public final long getCreationTick() { return this.d; } public final void setCreationTick(final long value) { this.d = value; } // Paper - OBFHELPER // Purpur - OBFHELPER
+    boolean isCached; // Purpur - delay chunk unloads, this defends against really stupid plugins
 
     protected Ticket(TicketType<T> tickettype, int i, T t0) {
         this.a = tickettype;
@@ -60,6 +61,7 @@ public final class Ticket<T> implements Comparable<Ticket<?>> {
         this.d = i;
     }
 
+    protected final boolean isExpired(long time) { return this.b(time); } // Purpur - OBFHELPER
     protected boolean b(long i) {
         long j = this.a.b();
 
diff --git a/src/main/java/net/minecraft/server/TicketType.java b/src/main/java/net/minecraft/server/TicketType.java
index 8055f5998..93587068f 100644
--- a/src/main/java/net/minecraft/server/TicketType.java
+++ b/src/main/java/net/minecraft/server/TicketType.java
@@ -23,6 +23,7 @@ public class TicketType<T> {
     public static final TicketType<org.bukkit.plugin.Plugin> PLUGIN_TICKET = a("plugin_ticket", (plugin1, plugin2) -> plugin1.getClass().getName().compareTo(plugin2.getClass().getName())); // CraftBukkit
     public static final TicketType<Long> FUTURE_AWAIT = a("future_await", Long::compareTo); // Paper
     public static final TicketType<Long> ASYNC_LOAD = a("async_load", Long::compareTo); // Paper
+    public static final TicketType<Long> DELAYED_UNLOAD = a("delayed_unload", Long::compareTo); // Purpur
 
     public static <T> TicketType<T> a(String s, Comparator<T> comparator) {
         return new TicketType<>(s, comparator, 0L);
diff --git a/src/main/java/net/pl3x/purpur/PurpurConfig.java b/src/main/java/net/pl3x/purpur/PurpurConfig.java
index ab88636ca..becb13e0e 100644
--- a/src/main/java/net/pl3x/purpur/PurpurConfig.java
+++ b/src/main/java/net/pl3x/purpur/PurpurConfig.java
@@ -4,6 +4,7 @@ import com.google.common.base.Throwables;
 import net.minecraft.server.Enchantment;
 import net.minecraft.server.IRegistry;
 import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.TicketType;
 import net.pl3x.purpur.command.PurpurCommand;
 import org.bukkit.Bukkit;
 import org.bukkit.command.Command;
@@ -206,4 +207,12 @@ public class PurpurConfig {
             enchantment.setMaxLevel(maxLevel);
         }
     }
+
+    public static int delayChunkUnloadsBy;
+    private static void delayChunkUnloadsBy() {
+        delayChunkUnloadsBy = getInt("settings.delay-chunk-unloads-by", 1) * 20;
+        if (delayChunkUnloadsBy >= 0) {
+            TicketType.DELAYED_UNLOAD.loadPeriod = delayChunkUnloadsBy;
+        }
+    }
 }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 6a50d7de3..513e84f76 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -487,6 +487,7 @@ public class CraftWorld implements World {
         net.minecraft.server.IChunkAccess chunk = world.getChunkProvider().getChunkAtIfLoadedImmediately(x, z); // Paper
         if (chunk != null) {
             world.getChunkProvider().removeTicket(TicketType.PLUGIN, chunk.getPos(), 1, Unit.INSTANCE);
+            ((ChunkMapDistance)world.getChunkProvider().playerChunkMap.getChunkMapDistanceManager()).removeTickets(ChunkCoordIntPair.pair(x, z), TicketType.DELAYED_UNLOAD); // Purpur - delay chunk unloads - let plugins override
         }
 
         return true;
-- 
2.24.0