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, 0 insertions, 216 deletions

diff --git a/patches/server/0759-Remove-streams-for-villager-AI.patch b/patches/server/0759-Remove-streams-for-villager-AI.patch
deleted file mode 100644
index 3af840ec77..0000000000
--- a/patches/server/0759-Remove-streams-for-villager-AI.patch
+++ /dev/null
@@ -1,216 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Spottedleaf <[email protected]>
-Date: Thu, 27 Aug 2020 20:51:40 -0700
-Subject: [PATCH] Remove streams for villager AI
-
-
-diff --git a/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java b/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java
-index 5a5d454b5987bb01d03f91c15b7a6bff46f1de71..c545539fc5d20cc69a0e5d2e261ef46a8f6fa4f0 100644
---- a/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java
-+++ b/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java
-@@ -30,11 +30,19 @@ public class GateBehavior<E extends LivingEntity> extends Behavior<E> {
- 
-     @Override
-     protected boolean canStillUse(ServerLevel world, E entity, long time) {
--        return this.behaviors.stream().filter((task) -> {
--            return task.getStatus() == Behavior.Status.RUNNING;
--        }).anyMatch((task) -> {
--            return task.canStillUse(world, entity, time);
--        });
-+        // Paper start - remove streams
-+        List<ShufflingList.WeightedEntry<Behavior<? super E>>> entries = this.behaviors.entries;
-+        for (int i = 0; i < entries.size(); i++) {
-+            ShufflingList.WeightedEntry<Behavior<? super E>> entry = entries.get(i);
-+            Behavior<? super E> behavior = entry.getData();
-+            if (behavior.getStatus() == Status.RUNNING) {
-+                if (behavior.canStillUse(world, entity, time)) {
-+                    return true;
-+                }
-+            }
-+        }
-+        return false;
-+        // Paper end - remove streams
-     }
- 
-     @Override
-@@ -45,25 +53,35 @@ public class GateBehavior<E extends LivingEntity> extends Behavior<E> {
-     @Override
-     protected void start(ServerLevel world, E entity, long time) {
-         this.orderPolicy.apply(this.behaviors);
--        this.runningPolicy.apply(this.behaviors.stream(), world, entity, time);
-+        this.runningPolicy.apply(this.behaviors.entries, world, entity, time); // Paper - remove streams
-     }
- 
-     @Override
-     protected void tick(ServerLevel world, E entity, long time) {
--        this.behaviors.stream().filter((task) -> {
--            return task.getStatus() == Behavior.Status.RUNNING;
--        }).forEach((task) -> {
--            task.tickOrStop(world, entity, time);
--        });
-+        // Paper start - remove streams
-+        List<ShufflingList.WeightedEntry<Behavior<? super E>>> entries = this.behaviors.entries;
-+        for (int i = 0; i < entries.size(); i++) {
-+            ShufflingList.WeightedEntry<Behavior<? super E>> entry = entries.get(i);
-+            Behavior<? super E> behavior = entry.getData();
-+            if (behavior.getStatus() == Status.RUNNING) {
-+                behavior.tickOrStop(world, entity, time);
-+            }
-+        }
-+        // Paper end - remove streams
-     }
- 
-     @Override
-     protected void stop(ServerLevel world, E entity, long time) {
--        this.behaviors.stream().filter((task) -> {
--            return task.getStatus() == Behavior.Status.RUNNING;
--        }).forEach((task) -> {
--            task.doStop(world, entity, time);
--        });
-+        // Paper start - remove streams
-+        List<ShufflingList.WeightedEntry<Behavior<? super E>>> entries = this.behaviors.entries;
-+        for (int i = 0; i < entries.size(); i++) {
-+            ShufflingList.WeightedEntry<Behavior<? super E>> entry = entries.get(i);
-+            Behavior<? super E> behavior = entry.getData();
-+            if (behavior.getStatus() == Status.RUNNING) {
-+                behavior.doStop(world, entity, time);
-+            }
-+        }
-+        // Paper end - remove streams
-         this.exitErasedMemories.forEach(entity.getBrain()::eraseMemory);
-     }
- 
-@@ -94,25 +112,33 @@ public class GateBehavior<E extends LivingEntity> extends Behavior<E> {
-     public static enum RunningPolicy {
-         RUN_ONE {
-             @Override
--            public <E extends LivingEntity> void apply(Stream<Behavior<? super E>> tasks, ServerLevel world, E entity, long time) {
--                tasks.filter((task) -> {
--                    return task.getStatus() == Behavior.Status.STOPPED;
--                }).filter((task) -> {
--                    return task.tryStart(world, entity, time);
--                }).findFirst();
-+            // Paper start - remove streams
-+            public <E extends LivingEntity> void apply(List<ShufflingList.WeightedEntry<Behavior<? super E>>> tasks, ServerLevel world, E entity, long time) {
-+                for (int i = 0; i < tasks.size(); i++) {
-+                    ShufflingList.WeightedEntry<Behavior<? super E>> task = tasks.get(i);
-+                    Behavior<? super E> behavior = task.getData();
-+                    if (behavior.getStatus() == Status.STOPPED && behavior.tryStart(world, entity, time)) {
-+                        break;
-+                    }
-+                }
-+                // Paper end - remove streams
-             }
-         },
-         TRY_ALL {
-             @Override
--            public <E extends LivingEntity> void apply(Stream<Behavior<? super E>> tasks, ServerLevel world, E entity, long time) {
--                tasks.filter((task) -> {
--                    return task.getStatus() == Behavior.Status.STOPPED;
--                }).forEach((task) -> {
--                    task.tryStart(world, entity, time);
--                });
-+            // Paper start - remove streams
-+            public <E extends LivingEntity> void apply(List<ShufflingList.WeightedEntry<Behavior<? super E>>> tasks, ServerLevel world, E entity, long time) {
-+                for (int i = 0; i < tasks.size(); i++) {
-+                    ShufflingList.WeightedEntry<Behavior<? super E>> task = tasks.get(i);
-+                    Behavior<? super E> behavior = task.getData();
-+                    if (behavior.getStatus() == Status.STOPPED) {
-+                        behavior.tryStart(world, entity, time);
-+                    }
-+                }
-+                // Paper end - remove streams
-             }
-         };
- 
--        public abstract <E extends LivingEntity> void apply(Stream<Behavior<? super E>> tasks, ServerLevel world, E entity, long time);
-+        public abstract <E extends LivingEntity> void apply(List<ShufflingList.WeightedEntry<Behavior<? super E>>> tasks, ServerLevel world, E entity, long time); // Paper - remove streams
-     }
- }
-diff --git a/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java b/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java
-index 090bba46b6ecd7d0e1415feb678b9b23264fe5e9..ca771d60283d94c00aa65d06ef93071e412357e8 100644
---- a/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java
-+++ b/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java
-@@ -12,7 +12,7 @@ import java.util.stream.Stream;
- import net.minecraft.util.RandomSource;
- 
- public class ShufflingList<U> {
--    protected final List<ShufflingList.WeightedEntry<U>> entries;
-+    public final List<ShufflingList.WeightedEntry<U>> entries; // Paper - public
-     private final RandomSource random = RandomSource.create();
-     private final boolean isUnsafe; // Paper
- 
-diff --git a/src/main/java/net/minecraft/world/entity/ai/sensing/NearestItemSensor.java b/src/main/java/net/minecraft/world/entity/ai/sensing/NearestItemSensor.java
-index 1dfcc5cba6ffb463acf161a23fff1ca452184290..2c4517850a9692f1c2b1332b58e8312fe1166772 100644
---- a/src/main/java/net/minecraft/world/entity/ai/sensing/NearestItemSensor.java
-+++ b/src/main/java/net/minecraft/world/entity/ai/sensing/NearestItemSensor.java
-@@ -25,13 +25,16 @@ public class NearestItemSensor extends Sensor<Mob> {
-     protected void doTick(ServerLevel world, Mob entity) {
-         Brain<?> brain = entity.getBrain();
-         List<ItemEntity> list = world.getEntitiesOfClass(ItemEntity.class, entity.getBoundingBox().inflate(32.0D, 16.0D, 32.0D), (itemEntity) -> {
--            return true;
-+            return itemEntity.closerThan(entity, 9.0D) && entity.wantsToPickUp(itemEntity.getItem()); // Paper - move predicate into getEntities
-         });
--        list.sort(Comparator.comparingDouble(entity::distanceToSqr));
-+        list.sort((e1, e2) -> Double.compare(entity.distanceToSqr(e1), entity.distanceToSqr(e2))); // better to take the sort perf hit than using line of sight more than we need to.
-+        // Paper start - remove streams
-         // Paper start - remove streams in favour of lists
-         ItemEntity nearest = null;
--        for (ItemEntity entityItem : list) {
--            if (entity.wantsToPickUp(entityItem.getItem()) && entityItem.closerThan(entity, 32.0D) && entity.hasLineOfSight(entityItem)) {
-+        for (int i = 0; i < list.size(); i++) {
-+            ItemEntity entityItem = list.get(i);
-+            if (entity.hasLineOfSight(entityItem)) {
-+                // Paper end - remove streams
-                 nearest = entityItem;
-                 break;
-             }
-diff --git a/src/main/java/net/minecraft/world/entity/ai/sensing/PlayerSensor.java b/src/main/java/net/minecraft/world/entity/ai/sensing/PlayerSensor.java
-index 312775d0430f793720211dc29bb293503e799d11..75d9c4f011b5a97def215784c92bb57bbb35d06b 100644
---- a/src/main/java/net/minecraft/world/entity/ai/sensing/PlayerSensor.java
-+++ b/src/main/java/net/minecraft/world/entity/ai/sensing/PlayerSensor.java
-@@ -21,25 +21,30 @@ public class PlayerSensor extends Sensor<LivingEntity> {
- 
-     @Override
-     protected void doTick(ServerLevel world, LivingEntity entity) {
--        List<Player> players = new java.util.ArrayList<>(world.players());
--        players.removeIf(player -> !EntitySelector.NO_SPECTATORS.test(player) || !entity.closerThan(player, 16.0D));
--        players.sort(Comparator.comparingDouble(entity::distanceTo));
-+        // Paper start - remove streams
-+        List<Player> players = (List)world.getNearbyPlayers(entity, entity.getX(), entity.getY(), entity.getZ(), 16.0D, EntitySelector.NO_SPECTATORS);
-+        players.sort((e1, e2) -> Double.compare(entity.distanceToSqr(e1), entity.distanceToSqr(e2)));
-         Brain<?> brain = entity.getBrain();
- 
-         brain.setMemory(MemoryModuleType.NEAREST_PLAYERS, players);
- 
--        Player nearest = null, nearestTargetable = null;
--        for (Player player : players) {
--            if (Sensor.isEntityTargetable(entity, player)) {
--                if (nearest == null) nearest = player;
--                if (Sensor.isEntityAttackable(entity, player)) {
--                    nearestTargetable = player;
--                    break; // Both variables are assigned, no reason to loop further
--                }
-+        Player firstTargetable = null;
-+        Player firstAttackable = null;
-+        for (int index = 0, len = players.size(); index < len; ++index) {
-+            Player player = players.get(index);
-+            if (firstTargetable == null && isEntityTargetable(entity, player)) {
-+                firstTargetable = player;
-+            }
-+            if (firstAttackable == null && isEntityAttackable(entity, player)) {
-+                firstAttackable = player;
-+            }
-+
-+            if (firstAttackable != null && firstTargetable != null) {
-+                break;
-             }
-         }
--        brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_PLAYER, nearest);
--        brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_ATTACKABLE_PLAYER, nearestTargetable);
--        // Paper end
-+        brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_PLAYER, firstTargetable);
-+        brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_ATTACKABLE_PLAYER, Optional.ofNullable(firstAttackable));
-+        // Paper end - remove streams
-     }
- }