PaperMC/patches/server/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 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 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
@@ -0,0 +0,0 @@ public abstract class BlockEntity {
         this.worldPosition = pos.immutable();
         this.validateBlockState(state);
         this.blockState = state;
+        this.persistentDataContainer = new CraftPersistentDataContainer(DATA_TYPE_REGISTRY); // Paper - always init
     }
 
     private void validateBlockState(BlockState state) {
@@ -0,0 +0,0 @@ public abstract class BlockEntity {
 
     // CraftBukkit start - read container
     protected void loadAdditional(CompoundTag nbt, HolderLookup.Provider registries) {
-        this.persistentDataContainer = new CraftPersistentDataContainer(BlockEntity.DATA_TYPE_REGISTRY);
+        this.persistentDataContainer.clear(); // Paper - clear instead of init
 
         net.minecraft.nbt.Tag persistentDataTag = nbt.get("PublicBukkitValues");
         if (persistentDataTag instanceof CompoundTag) {
@@ -0,0 +0,0 @@ public abstract class BlockEntity {
 
     // CraftBukkit start - add method
     public InventoryHolder getOwner() {
+        // Paper start
+        return getOwner(true);
+    }
+    public InventoryHolder getOwner(boolean useSnapshot) {
+        // Paper end
         if (this.level == null) return null;
-        org.bukkit.block.BlockState state = this.level.getWorld().getBlockAt(this.worldPosition.getX(), this.worldPosition.getY(), this.worldPosition.getZ()).getState();
+        org.bukkit.block.Block block = this.level.getWorld().getBlockAt(this.worldPosition.getX(), this.worldPosition.getY(), this.worldPosition.getZ());
+        if (block.getType() == org.bukkit.Material.AIR) return null;
+        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 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
@@ -0,0 +0,0 @@ public class CraftBlock implements Block {
         return CraftBlockStates.getBlockState(this);
     }
 
+    // Paper start
+    @Override
+    public BlockState getState(boolean useSnapshot) {
+        return CraftBlockStates.getBlockState(this, useSnapshot);
+    }
+    // Paper end
+
     @Override
     public Biome getBiome() {
         return this.getWorld().getBiome(this.getX(), this.getY(), this.getZ());
diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
@@ -0,0 +0,0 @@ public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockStat
 
     private final T tileEntity;
     private final T snapshot;
+    public boolean snapshotDisabled; // Paper
+    public static boolean DISABLE_SNAPSHOT = false; // Paper
 
     public CraftBlockEntityState(World world, T tileEntity) {
         super(world, tileEntity.getBlockPos(), tileEntity.getBlockState());
 
         this.tileEntity = tileEntity;
 
+        // Paper start
+        this.snapshotDisabled = DISABLE_SNAPSHOT;
+        if (DISABLE_SNAPSHOT) {
+            this.snapshot = this.tileEntity;
+        } else {
+            this.snapshot = this.createSnapshot(tileEntity);
+        }
         // copy tile entity data:
-        this.snapshot = this.createSnapshot(tileEntity);
-        this.load(this.snapshot);
+        if (this.snapshot != null) {
+            this.load(this.snapshot);
+        }
+        // Paper end
     }
 
     protected CraftBlockEntityState(CraftBlockEntityState<T> state, Location location) {
@@ -0,0 +0,0 @@ public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockStat
     public CraftBlockEntityState<T> copy(Location location) {
         return new CraftBlockEntityState<>(this, location);
     }
+
+    // Paper start
+    @Override
+    public boolean isSnapshot() {
+        return !this.snapshotDisabled;
+    }
+    // Paper end
 }
diff --git a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
@@ -0,0 +0,0 @@ public final class CraftBlockStates {
     }
 
     public static BlockState getBlockState(Block block) {
+        // Paper start
+        return CraftBlockStates.getBlockState(block, true);
+    }
+    public static BlockState getBlockState(Block block, boolean useSnapshot) {
+        // Paper end
         Preconditions.checkNotNull(block, "block is null");
         CraftBlock craftBlock = (CraftBlock) block;
         CraftWorld world = (CraftWorld) block.getWorld();
         BlockPos blockPosition = craftBlock.getPosition();
         net.minecraft.world.level.block.state.BlockState blockData = craftBlock.getNMS();
         BlockEntity tileEntity = craftBlock.getHandle().getBlockEntity(blockPosition);
+        // Paper start - block state snapshots
+        boolean prev = CraftBlockEntityState.DISABLE_SNAPSHOT;
+        CraftBlockEntityState.DISABLE_SNAPSHOT = !useSnapshot;
+        try {
+        // Paper end
         CraftBlockState blockState = CraftBlockStates.getBlockState(world, blockPosition, blockData, tileEntity);
         blockState.setWorldHandle(craftBlock.getHandle()); // Inject the block's generator access
         return blockState;
+        // Paper start
+        } finally {
+            CraftBlockEntityState.DISABLE_SNAPSHOT = prev;
+        }
+        // Paper end
     }
 
     @Deprecated
diff --git a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
+++ b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
@@ -0,0 +0,0 @@ public class CraftPersistentDataContainer implements PersistentDataContainer {
     public String serialize() {
         return CraftNBTTagConfigSerializer.serialize(this.toTagCompound());
     }
+
+    // Paper start
+    public void clear() {
+        this.customDataTags.clear();
+    }
+    // Paper end
 }