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, 57 insertions, 0 deletions

diff --git a/patches/server/0137-Item-canEntityPickup.patch b/patches/server/0137-Item-canEntityPickup.patch
new file mode 100644
index 0000000000..07b208cc78
--- /dev/null
+++ b/patches/server/0137-Item-canEntityPickup.patch
@@ -0,0 +1,57 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: BillyGalbreath <[email protected]>
+Date: Fri, 5 May 2017 03:57:17 -0500
+Subject: [PATCH] Item#canEntityPickup
+
+
+diff --git a/src/main/java/net/minecraft/world/entity/Mob.java b/src/main/java/net/minecraft/world/entity/Mob.java
+index 0b056e65b2efe0f96a6beecfc41709bfa18983ca..6d0d194aaababd91a26dffc07f547d60eadd098e 100644
+--- a/src/main/java/net/minecraft/world/entity/Mob.java
++++ b/src/main/java/net/minecraft/world/entity/Mob.java
+@@ -635,6 +635,11 @@ public abstract class Mob extends LivingEntity {
+                 ItemEntity entityitem = (ItemEntity) iterator.next();
+ 
+                 if (!entityitem.isRemoved() && !entityitem.getItem().isEmpty() && !entityitem.hasPickUpDelay() && this.wantsToPickUp(entityitem.getItem())) {
++                    // Paper Start
++                    if (!entityitem.canMobPickup) {
++                        continue;
++                    }
++                    // Paper End
+                     this.pickUpItem(entityitem);
+                 }
+             }
+diff --git a/src/main/java/net/minecraft/world/entity/item/ItemEntity.java b/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
+index a938d75e229ce77973182c9dd25c995a16ef17f6..581725ab12f6bea1216dbf62d5cf3923d4340844 100644
+--- a/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
++++ b/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
+@@ -52,6 +52,7 @@ public class ItemEntity extends Entity {
+     private UUID owner;
+     public final float bobOffs;
+     private int lastTick = MinecraftServer.currentTick - 1; // CraftBukkit
++    public boolean canMobPickup = true; // Paper
+ 
+     public ItemEntity(EntityType<? extends ItemEntity> type, Level world) {
+         super(type, world);
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java
+index 4ca76a7530f8679567d887cdf1491d110e7465ec..30c954efba587d69ff55df509339f03e7d5a476e 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java
+@@ -66,6 +66,18 @@ public class CraftItem extends CraftEntity implements Item {
+         }
+     }
+ 
++    // Paper Start
++    @Override
++    public boolean canMobPickup() {
++        return item.canMobPickup;
++    }
++
++    @Override
++    public void setCanMobPickup(boolean canMobPickup) {
++        item.canMobPickup = canMobPickup;
++    }
++    // Paper End
++
+     @Override
+     public void setOwner(UUID uuid) {
+         this.item.setOwner(uuid);