Limit item frame cursors on maps (#5730)

Fixes an issue where you can have thousands of these and lag clients.

Spigot-Server-Patches/0747-Limit-item-frame-cursors-on-maps.patch

@@ -0,0 +1,37 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Yive <admin@yive.me>
+Date: Wed, 26 May 2021 15:09:33 -0700
+Subject: [PATCH] Limit item frame cursors on maps
+
+
+diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+index 921253a06daa414aed7dc6824effc65db09ea7a5..37f866629b7eed39ced4352c94e56c8de8ccfeb9 100644
+--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
++++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+@@ -815,4 +815,9 @@ public class PaperWorldConfig {
+     private void allowUsingSignsInsideSpawnProtection() {
+         allowUsingSignsInsideSpawnProtection = getBoolean("allow-using-signs-inside-spawn-protection", allowUsingSignsInsideSpawnProtection);
+     }
++
++    public int mapItemFrameCursorLimit = 128;
++    private void mapItemFrameCursorLimit() {
++        mapItemFrameCursorLimit = getInt("map-item-frame-cursor-limit", mapItemFrameCursorLimit);
++    }
+ }
+diff --git a/src/main/java/net/minecraft/world/level/saveddata/maps/WorldMap.java b/src/main/java/net/minecraft/world/level/saveddata/maps/WorldMap.java
+index 1f9b710f2af3c5067b3c2b73bebb11f8e22c403e..97fe61dcd066ec0ee05e81fc22409d6aa6b3a6d5 100644
+--- a/src/main/java/net/minecraft/world/level/saveddata/maps/WorldMap.java
++++ b/src/main/java/net/minecraft/world/level/saveddata/maps/WorldMap.java
+@@ -279,8 +279,12 @@ public class WorldMap extends PersistentBase {
+ 
+             WorldMapFrame worldmapframe1 = new WorldMapFrame(blockposition, entityitemframe.getDirection().get2DRotationValue() * 90, entityitemframe.getId());
+ 
++            // Paper start
++            if (this.decorations.size() < entityhuman.world.paperConfig.mapItemFrameCursorLimit) {
+             this.a(MapIcon.Type.FRAME, entityhuman.world, "frame-" + entityitemframe.getId(), (double) blockposition.getX(), (double) blockposition.getZ(), (double) (entityitemframe.getDirection().get2DRotationValue() * 90), (IChatBaseComponent) null);
+             this.n.put(worldmapframe1.e(), worldmapframe1);
++            }
++            // Paper end
+         }
+ 
+         NBTTagCompound nbttagcompound = itemstack.getTag();