Paper/patches/server/0168-API-to-get-a-BlockState-without-a-snapshot.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 6 Nov 2017 21:08:22 -0500
Subject: [PATCH] API to get a BlockState without a snapshot

This allows you to get a BlockState without creating a snapshot, operating
on the real tile entity.

This is useful for where performance is needed

also Avoid NPE during CraftBlockEntityState load if could not get TE

If Tile Entity was null, correct Sign to return empty lines instead of null

diff --git a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
index 77645019c88d61dde28b7598d8a29b7d0c23c209..8a079ee3ed243fd19b1dd7eed2de1dd33785faa1 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
@@ -42,6 +42,7 @@ public abstract class BlockEntity implements net.minecraft.server.KeyedObject {
         this.type = type;
         this.worldPosition = pos.immutable();
         this.blockState = state;
+        persistentDataContainer = new CraftPersistentDataContainer(DATA_TYPE_REGISTRY); // Paper - always init
     }
 
     // Paper start
@@ -79,7 +80,7 @@ public abstract class BlockEntity implements net.minecraft.server.KeyedObject {
 
     // CraftBukkit start - read container
     public void load(CompoundTag nbt) {
-        this.persistentDataContainer = new CraftPersistentDataContainer(BlockEntity.DATA_TYPE_REGISTRY);
+        this.persistentDataContainer.clear();
 
         net.minecraft.nbt.Tag persistentDataTag = nbt.get("PublicBukkitValues");
         if (persistentDataTag instanceof CompoundTag) {
@@ -221,8 +222,13 @@ public abstract class BlockEntity implements net.minecraft.server.KeyedObject {
     }
 
     // CraftBukkit start - add method
+    // Paper start
     public InventoryHolder getOwner() {
-        if (this.level == null) return null;
+        return getOwner(true);
+    }
+    public InventoryHolder getOwner(boolean useSnapshot) {
+        // Paper end
+        if (level == null) return null;
         // Spigot start
         org.bukkit.block.Block block = this.level.getWorld().getBlockAt(this.worldPosition.getX(), this.worldPosition.getY(), this.worldPosition.getZ());
         if (block == null) {
@@ -230,7 +236,7 @@ public abstract class BlockEntity implements net.minecraft.server.KeyedObject {
             return null;
         }
         // Spigot end
-        org.bukkit.block.BlockState state = block.getState();
+        org.bukkit.block.BlockState state = block.getState(useSnapshot); // Paper
         if (state instanceof InventoryHolder) return (InventoryHolder) state;
         return null;
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
index 923948e7fc63a778ca126c99e1189357bb490dee..bf12cb6a1f991372206e462e46f2686decff11a6 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
@@ -316,7 +316,21 @@ public class CraftBlock implements Block {
 
     @Override
     public BlockState getState() {
-        Material material = this.getType();
+        // Paper start - allow disabling the use of snapshots
+        return getState(true);
+    }
+    public BlockState getState(boolean useSnapshot) {
+        boolean prev = CraftBlockEntityState.DISABLE_SNAPSHOT;
+        CraftBlockEntityState.DISABLE_SNAPSHOT = !useSnapshot;
+        try {
+            return getState0();
+        } finally {
+            CraftBlockEntityState.DISABLE_SNAPSHOT = prev;
+        }
+    }
+    public BlockState getState0() {
+        // Paper end
+        Material material = getType();
 
         switch (material) {
             case ACACIA_SIGN:
diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
index fd5b5287d67af364f149d4e284001fd319986bd5..972d4aa11a0a119e8e6703af99d93bcd3cddc6d8 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
@@ -26,20 +26,40 @@ public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockStat
         this.tileEntity = tileEntityClass.cast(world.getHandle().getBlockEntity(this.getPosition()));
         Preconditions.checkState(this.tileEntity != null, "Tile is null, asynchronous access? %s", block);
 
+        // Paper start
+        this.snapshotDisabled = DISABLE_SNAPSHOT;
+        if (DISABLE_SNAPSHOT) {
+            this.snapshot = this.tileEntity;
+        } else {
+            this.snapshot = this.createSnapshot(this.tileEntity);
+        }
         // copy tile entity data:
-        this.snapshot = this.createSnapshot(tileEntity);
-        this.load(snapshot);
+        if(this.snapshot != null) {
+            this.load(this.snapshot);
+        }
+        // Paper end
     }
 
+    public final boolean snapshotDisabled; // Paper
+    public static boolean DISABLE_SNAPSHOT = false; // Paper
+
     public CraftBlockEntityState(Material material, T tileEntity) {
         super(material);
 
         this.tileEntityClass = (Class<T>) tileEntity.getClass();
         this.tileEntity = tileEntity;
-
+        // Paper start
+        this.snapshotDisabled = DISABLE_SNAPSHOT;
+        if (DISABLE_SNAPSHOT) {
+            this.snapshot = this.tileEntity;
+        } else {
+            this.snapshot = this.createSnapshot(this.tileEntity);
+        }
         // copy tile entity data:
-        this.snapshot = this.createSnapshot(tileEntity);
-        this.load(snapshot);
+        if(this.snapshot != null) {
+            this.load(this.snapshot);
+        }
+        // Paper end
     }
 
     private T createSnapshot(T tileEntity) {
diff --git a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
index ddd7b63f0452042baa3fca04bb9fbdb42fcecbfd..b638351581fa09c488425a2318b782a5812140ce 100644
--- a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
+++ b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
@@ -155,4 +155,10 @@ public final class CraftPersistentDataContainer implements PersistentDataContain
     public Map<String, Object> serialize() {
         return (Map<String, Object>) CraftNBTTagConfigSerializer.serialize(this.toTagCompound());
     }
+
+    // Paper start
+    public void clear() {
+        this.customDataTags.clear();
+    }
+    // Paper end
 }