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 148e79ae4e24fe16dbbb17550c3f258d4362c266..06beb18e5e1950aeb6cb427876fcc4c5ea95adb2 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
@@ -45,6 +45,7 @@ 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) {
@@ -66,7 +67,7 @@ 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) {
@@ -240,8 +241,15 @@ 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 52fc42050d5df0882586c8f4bb4890ef1dbf979e..ba8f9ffed49bf377be8b37532d4f2bdcb8c44d82 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java
@@ -329,6 +329,13 @@ 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 7629a51ec284cab0db7e9238027d6acfa4f3083c..a76cce199acdcecfdd8b998ec08974c2ed0751cf 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockEntityState.java
@@ -10,15 +10,26 @@ public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockStat
 
     private final T tileEntity;
     private final T snapshot;
+    public final 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(snapshot);
+        if (this.snapshot != null) {
+            this.load(this.snapshot);
+        }
+        // Paper end
     }
 
     public void refreshSnapshot() {
@@ -105,4 +116,11 @@ public class CraftBlockEntityState<T extends BlockEntity> extends CraftBlockStat
     public PersistentDataContainer getPersistentDataContainer() {
         return this.getSnapshot().persistentDataContainer;
     }
+
+    // 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 521d981e72955b1e2c96427882e336b034456678..e609cfeaf5aa6807f57360dde9b0dccf40a23eb1 100644
--- a/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
+++ b/src/main/java/org/bukkit/craftbukkit/block/CraftBlockStates.java
@@ -336,15 +336,30 @@ 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 3fc3907172f12ee24ea70bd6a1ffbbc6084ed971..2c59f09a9261a1690951161fd856a5848d9885b7 100644
--- a/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
+++ b/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java
@@ -156,4 +156,10 @@ public class CraftPersistentDataContainer implements PersistentDataContainer {
     public Map<String, Object> serialize() {
         return (Map<String, Object>) CraftNBTTagConfigSerializer.serialize(this.toTagCompound());
     }
+
+    // Paper start
+    public void clear() {
+        this.customDataTags.clear();
+    }
+    // Paper end
 }