Rewrite chunk system (#8177)

Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.

1 files changed, 143 insertions, 0 deletions

diff --git a/patches/server/0028-Player-affects-spawning-API.patch b/patches/server/0028-Player-affects-spawning-API.patch
new file mode 100644
index 0000000000..db71dd0ac3
--- /dev/null
+++ b/patches/server/0028-Player-affects-spawning-API.patch
@@ -0,0 +1,143 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jedediah Smith <[email protected]>
+Date: Tue, 1 Mar 2016 14:47:52 -0600
+Subject: [PATCH] Player affects spawning API
+
+
+diff --git a/src/main/java/net/minecraft/world/entity/EntitySelector.java b/src/main/java/net/minecraft/world/entity/EntitySelector.java
+index 5c3b11f738c1ea19981cc878aa6c2323497391a0..b91a61be7c4829fce0ff8da290eab580e20bb78d 100644
+--- a/src/main/java/net/minecraft/world/entity/EntitySelector.java
++++ b/src/main/java/net/minecraft/world/entity/EntitySelector.java
+@@ -29,6 +29,11 @@ public final class EntitySelector {
+     public static final Predicate<Entity> CAN_BE_COLLIDED_WITH = EntitySelector.NO_SPECTATORS.and(Entity::canBeCollidedWith);
+ 
+     private EntitySelector() {}
++    // Paper start
++    public static final Predicate<Entity> affectsSpawning = (entity) -> {
++        return !entity.isSpectator() && entity.isAlive() && (entity instanceof net.minecraft.server.level.ServerPlayer) && ((net.minecraft.server.level.ServerPlayer) entity).affectsSpawning;
++    };
++    // Paper end
+ 
+     public static Predicate<Entity> withinDistance(double x, double y, double z, double max) {
+         double d4 = max * max;
+diff --git a/src/main/java/net/minecraft/world/entity/Mob.java b/src/main/java/net/minecraft/world/entity/Mob.java
+index ce04fa5ae8c539fd6f6aa7648a4cdce6b680463e..0b056e65b2efe0f96a6beecfc41709bfa18983ca 100644
+--- a/src/main/java/net/minecraft/world/entity/Mob.java
++++ b/src/main/java/net/minecraft/world/entity/Mob.java
+@@ -790,7 +790,7 @@ public abstract class Mob extends LivingEntity {
+         if (this.level.getDifficulty() == Difficulty.PEACEFUL && this.shouldDespawnInPeaceful()) {
+             this.discard();
+         } else if (!this.isPersistenceRequired() && !this.requiresCustomPersistence()) {
+-            Player entityhuman = this.level.getNearestPlayer(this, -1.0D);
++            Player entityhuman = this.level.findNearbyPlayer(this, -1.0D, EntitySelector.affectsSpawning); // Paper
+ 
+             if (entityhuman != null) {
+                 double d0 = entityhuman.distanceToSqr((Entity) this);
+diff --git a/src/main/java/net/minecraft/world/entity/monster/Silverfish.java b/src/main/java/net/minecraft/world/entity/monster/Silverfish.java
+index 87f66fd33e404367d924137b2d8aac3b06937f43..2dcda3b03796655da443e1b3dd68c6f6bca20d21 100644
+--- a/src/main/java/net/minecraft/world/entity/monster/Silverfish.java
++++ b/src/main/java/net/minecraft/world/entity/monster/Silverfish.java
+@@ -127,7 +127,7 @@ public class Silverfish extends Monster {
+         if (checkAnyLightMonsterSpawnRules(type, world, spawnReason, pos, random)) {
+             Player entityhuman = world.getNearestPlayer((double) pos.getX() + 0.5D, (double) pos.getY() + 0.5D, (double) pos.getZ() + 0.5D, 5.0D, true);
+ 
+-            return entityhuman == null;
++            return !(entityhuman != null && !entityhuman.affectsSpawning) && entityhuman == null; // Paper - Affects Spawning API
+         } else {
+             return false;
+         }
+diff --git a/src/main/java/net/minecraft/world/entity/player/Player.java b/src/main/java/net/minecraft/world/entity/player/Player.java
+index 0232baa005e2839317d7ac2d64c88fb93bc29e5e..08b0b7b9146f58c4eb263d5ce1fee1b08d43fafe 100644
+--- a/src/main/java/net/minecraft/world/entity/player/Player.java
++++ b/src/main/java/net/minecraft/world/entity/player/Player.java
+@@ -184,6 +184,9 @@ public abstract class Player extends LivingEntity {
+     private Optional<GlobalPos> lastDeathLocation;
+     @Nullable
+     public FishingHook fishing;
++    // Paper start
++    public boolean affectsSpawning = true;
++    // Paper end
+ 
+     // CraftBukkit start
+     public boolean fauxSleeping;
+diff --git a/src/main/java/net/minecraft/world/level/BaseSpawner.java b/src/main/java/net/minecraft/world/level/BaseSpawner.java
+index ab22310d5ab4ad7014b88080cbd44a2881002b55..c5b9b19763fd944b4f31c6d3c9b71d372f8403cf 100644
+--- a/src/main/java/net/minecraft/world/level/BaseSpawner.java
++++ b/src/main/java/net/minecraft/world/level/BaseSpawner.java
+@@ -51,7 +51,7 @@ public abstract class BaseSpawner {
+     }
+ 
+     public boolean isNearPlayer(Level world, BlockPos pos) {
+-        return world.hasNearbyAlivePlayer((double) pos.getX() + 0.5D, (double) pos.getY() + 0.5D, (double) pos.getZ() + 0.5D, (double) this.requiredPlayerRange);
++        return world.isAffectsSpawningPlayerNearby((double) pos.getX() + 0.5D, (double) pos.getY() + 0.5D, (double) pos.getZ() + 0.5D, (double) this.requiredPlayerRange); // Paper
+     }
+ 
+     public void clientTick(Level world, BlockPos pos) {
+diff --git a/src/main/java/net/minecraft/world/level/EntityGetter.java b/src/main/java/net/minecraft/world/level/EntityGetter.java
+index f62e4e36dd26bde067e4787fd0da1440b15a57fa..be2ec73b5900354a9c340b0a03affd59dbf55377 100644
+--- a/src/main/java/net/minecraft/world/level/EntityGetter.java
++++ b/src/main/java/net/minecraft/world/level/EntityGetter.java
+@@ -82,8 +82,8 @@ public interface EntityGetter {
+         }
+     }
+ 
+-    @Nullable
+-    default Player getNearestPlayer(double x, double y, double z, double maxDistance, @Nullable Predicate<Entity> targetPredicate) {
++    default Player findNearbyPlayer(Entity entity, double d0, @Nullable Predicate<Entity> predicate) { return this.getNearestPlayer(entity.getX(), entity.getY(), entity.getZ(), d0, predicate); } // Paper
++    @Nullable default Player getNearestPlayer(double x, double y, double z, double maxDistance, @Nullable Predicate<Entity> targetPredicate) { // Paper
+         double d = -1.0D;
+         Player player = null;
+ 
+@@ -111,6 +111,27 @@ public interface EntityGetter {
+         return this.getNearestPlayer(x, y, z, maxDistance, predicate);
+     }
+ 
++    // Paper end
++    default boolean isAffectsSpawningPlayerNearby(double d0, double d1, double d2, double d3) {
++        java.util.Iterator iterator = this.players().iterator();
++        double d4;
++        do {
++            Player entityhuman;
++            do {
++                if (!iterator.hasNext()) {
++                    return false;
++                }
++
++                entityhuman = (Player) iterator.next();
++            } while (!EntitySelector.affectsSpawning.test(entityhuman));
++
++            d4 = entityhuman.distanceToSqr(d0, d1, d2);
++        } while (d3 >= 0.0D && d4 >= d3 * d3);
++
++        return true;
++    }
++    // Paper end
++
+     default boolean hasNearbyAlivePlayer(double x, double y, double z, double range) {
+         for(Player player : this.players()) {
+             if (EntitySelector.NO_SPECTATORS.test(player) && EntitySelector.LIVING_ENTITY_STILL_ALIVE.test(player)) {
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index 6708c2c88251f4e5f623cd785c14b2d3ed2d3de0..182881c867e68e59e89f56f8dc66001b0d2b3add 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -2084,8 +2084,20 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+     @Override
+     public String getLocale() {
+         return this.getHandle().locale;
++
++    }
++
++    // Paper start
++    public void setAffectsSpawning(boolean affects) {
++        this.getHandle().affectsSpawning = affects;
+     }
+ 
++    @Override
++    public boolean getAffectsSpawning() {
++        return this.getHandle().affectsSpawning;
++    }
++    // Paper end
++
+     @Override
+     public void updateCommands() {
+         if (this.getHandle().connection == null) return;