Add PersistentDataContainerView#getSize (#13157)

Author: zBinFinn

paper-api/src/main/java/io/papermc/paper/persistence/PersistentDataContainerView.java

@@ -157,4 +157,9 @@ public interface PersistentDataContainerView {
      * @throws java.io.IOException if we fail to write this container to a byte array
      */
     byte[] serializeToBytes() throws java.io.IOException;
+
+    /**
+     * {@return the size of the data container}
+     */
+    int getSize();
 }

paper-server/src/main/java/org/bukkit/craftbukkit/CraftOfflinePlayer.java

@@ -320,6 +320,11 @@ public CompoundTag toTagCompound() {
                 public net.minecraft.nbt.Tag getTag(String key) {
                     return net.minecraft.Optionull.map(this.getPersistentTag(), tag -> tag.get(key));
                 }
+
+                @Override
+                public int getSize() {
+                    return this.getPersistentTag().size();
+                }
             };
         }
         return this.persistentDataContainerView;

paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemStack.java

@@ -496,6 +496,11 @@ private net.minecraft.nbt.CompoundTag getPdcTag() {
     private static final org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry REGISTRY = new org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry();
     private final io.papermc.paper.persistence.PaperPersistentDataContainerView pdcView = new io.papermc.paper.persistence.PaperPersistentDataContainerView(REGISTRY) {
 
+        @Override
+        public int getSize() {
+            return CraftItemStack.this.getPdcTag().size();
+        }
+
         @Override
         public net.minecraft.nbt.CompoundTag toTagCompound() {
             return CraftItemStack.this.getPdcTag();

paper-server/src/main/java/org/bukkit/craftbukkit/persistence/CraftPersistentDataContainer.java

@@ -170,4 +170,9 @@ public static Codec<CraftPersistentDataContainer> createCodec(final CraftPersist
             return container;
         }, CraftPersistentDataContainer::toTagCompound);
     }
+
+    @Override
+    public int getSize() {
+        return this.customDataTags.size();
+    }
 }