Paper/patches/server/0164-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 63acd109a79ed752a05df3d4f1b99309297c2055..d156f7cc71050f13b2feca00c52ca6b64572b60e 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
@@ -44,6 +44,7 @@ public abstract class BlockEntity {
         this.type = type;
         this.worldPosition = pos.immutable();
         this.blockState = state;
+        this.persistentDataContainer = new CraftPersistentDataContainer(DATA_TYPE_REGISTRY); // Paper - always init
     }
 
     public static BlockPos getPosFromTag(CompoundTag nbt) {
@@ -65,7 +66,7 @@ public abstract class BlockEntity {
 
     // CraftBukkit start - read container
     public void load(CompoundTag nbt) {
-        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) {
@@ -239,8 +240,15 @@ 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 61d696a59d7bea0b1908fe4fb63e4143bb1e218d..29bbd44a0d15d78e13d91003fea1460efdf19e88 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
@@ -328,6 +328,13 @@ 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 22af1b41eec06d660dbe47c463014bcdd96fc5b6..f046f507a095e0cb8f839b9b4b06add3a671486b 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
@@ -17,15 +17,26 @@ 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) {
@@ -136,4 +147,11 @@ public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockStat
     public CraftBlockEntityState<T> copy() {
         return new CraftBlockEntityState<>(this);
     }
+
+    // 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 183d6146dec231629b4892fcb2fe96d88cc74b4c..2fe8f7dfefd6e1f9b06f1d4821894091a8e6400e 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
@@ -383,15 +383,30 @@ 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
     }
 
     public static BlockState getBlockState(Material material, @Nullable CompoundTag blockEntityTag) {
diff --git a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
index cf9f0a8a8d2582e17e9b54269966bbfd4d9ae2a0..268563389077f92921411e866ec26e312e33ee23 100644
--- a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
+++ b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
@@ -173,4 +173,10 @@ public class CraftPersistentDataContainer implements PersistentDataContainer {
     public String serialize() {
         return CraftNBTTagConfigSerializer.serialize(this.toTagCompound());
     }
+
+    // Paper start
+    public void clear() {
+        this.customDataTags.clear();
+    }
+    // Paper end
 }