From 370f3c18ba4e014a8894627da9a2ae662c791b3d Mon Sep 17 00:00:00 2001
From: Camotoy <20743703+Camotoy@users.noreply.github.com>
Date: Wed, 10 Mar 2021 13:54:09 -0500
Subject: [PATCH] Use compute for determining if a lectern if present

Reduces having to call both containsKey and get.
---
 .../world/block/BlockStateValues.java         |  9 ++++-
 .../geysermc/connector/utils/ChunkUtils.java  | 37 ++++++++++---------
 2 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/connector/src/main/java/org/geysermc/connector/network/translators/world/block/BlockStateValues.java b/connector/src/main/java/org/geysermc/connector/network/translators/world/block/BlockStateValues.java
index ebc90b722..ff51562b9 100644
--- a/connector/src/main/java/org/geysermc/connector/network/translators/world/block/BlockStateValues.java
+++ b/connector/src/main/java/org/geysermc/connector/network/translators/world/block/BlockStateValues.java
@@ -29,6 +29,7 @@ import com.fasterxml.jackson.databind.JsonNode;
 import it.unimi.dsi.fastutil.ints.*;
 
 import java.util.Map;
+import java.util.function.BiFunction;
 
 /**
  * Used for block entities if the Java block state contains Bedrock block information.
@@ -199,7 +200,13 @@ public class BlockStateValues {
         return FLOWER_POT_VALUES;
     }
 
-    public static Int2BooleanMap getLecternBookStates() {
+    /**
+     * This returns a Map interface so IntelliJ doesn't complain about {@link Int2BooleanMap#compute(int, BiFunction)}
+     * not returning null.
+     *
+     * @return the lectern book state map pointing to book present state
+     */
+    public static Map<Integer, Boolean> getLecternBookStates() {
         return LECTERN_BOOK_STATES;
     }
 
diff --git a/connector/src/main/java/org/geysermc/connector/utils/ChunkUtils.java b/connector/src/main/java/org/geysermc/connector/utils/ChunkUtils.java
index b3a31e1ab..7d5b56615 100644
--- a/connector/src/main/java/org/geysermc/connector/utils/ChunkUtils.java
+++ b/connector/src/main/java/org/geysermc/connector/utils/ChunkUtils.java
@@ -372,27 +372,30 @@ public class ChunkUtils {
         }
         session.sendUpstreamPacket(waterPacket);
 
-        if (BlockStateValues.getLecternBookStates().containsKey(blockState)) {
-            boolean lecternCachedHasBook = session.getLecternCache().contains(position);
-            boolean newLecternHasBook = BlockStateValues.getLecternBookStates().get(blockState);
-            if (!session.getConnector().getWorldManager().shouldExpectLecternHandled() && lecternCachedHasBook != newLecternHasBook) {
-                // Refresh the block entirely - it either has a book or no longer has a book
-                NbtMap newLecternTag;
-                if (newLecternHasBook) {
-                    newLecternTag = session.getConnector().getWorldManager().getLecternDataAt(session, position.getX(), position.getY(), position.getZ(), false);
+        BlockStateValues.getLecternBookStates().compute(blockState, (key, newLecternHasBook) -> {
+            // Determine if this block is a lectern
+            if (newLecternHasBook != null) {
+                boolean lecternCachedHasBook = session.getLecternCache().contains(position);
+                if (!session.getConnector().getWorldManager().shouldExpectLecternHandled() && lecternCachedHasBook != newLecternHasBook) {
+                    // Refresh the block entirely - it either has a book or no longer has a book
+                    NbtMap newLecternTag;
+                    if (newLecternHasBook) {
+                        newLecternTag = session.getConnector().getWorldManager().getLecternDataAt(session, position.getX(), position.getY(), position.getZ(), false);
+                    } else {
+                        session.getLecternCache().remove(position);
+                        newLecternTag = LecternInventoryTranslator.getBaseLecternTag(position.getX(), position.getY(), position.getZ(), 0).build();
+                    }
+                    BlockEntityUtils.updateBlockEntity(session, newLecternTag, position);
                 } else {
-                    session.getLecternCache().remove(position);
-                    newLecternTag = LecternInventoryTranslator.getBaseLecternTag(position.getX(), position.getY(), position.getZ(), 0).build();
+                    // As of right now, no tag can be added asynchronously
+                    session.getConnector().getWorldManager().getLecternDataAt(session, position.getX(), position.getY(), position.getZ(), false);
                 }
-                BlockEntityUtils.updateBlockEntity(session, newLecternTag, position);
             } else {
-                // As of right now, no tag can be added asynchronously
-                session.getConnector().getWorldManager().getLecternDataAt(session, position.getX(), position.getY(), position.getZ(), false);
+                // Lectern has been destroyed, if it existed
+                session.getLecternCache().remove(position);
             }
-        } else {
-            // Lectern has been destroyed, if it existed
-            session.getLecternCache().remove(position);
-        }
+            return newLecternHasBook;
+        });
 
         // Since Java stores bed colors/skull information as part of the namespaced ID and Bedrock stores it as a tag
         // This is the only place I could find that interacts with the Java block state and block updates