Proposer serialization of itemStack and other Serializable stuff in Bukkit API

pandalib-paper/src/main/java/fr/pandacube/lib/paper/json/ConfigurationSerializableAdapter.java

@@ -0,0 +1,49 @@
+package fr.pandacube.lib.paper.json;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.internal.bind.TreeTypeAdapter;
+import com.google.gson.reflect.TypeToken;
+import org.bukkit.configuration.serialization.ConfigurationSerializable;
+import org.bukkit.configuration.serialization.ConfigurationSerialization;
+import org.bukkit.inventory.ItemStack;
+
+import java.lang.reflect.Type;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/* package */ class ConfigurationSerializableAdapter implements JsonSerializer<ConfigurationSerializable>, JsonDeserializer<ConfigurationSerializable> {
+
+    public static final TypeAdapterFactory FACTORY = TreeTypeAdapter.newTypeHierarchyFactory(ConfigurationSerializable.class, new ConfigurationSerializableAdapter());
+
+    private static final TypeToken<Map<String, Object>> MAP_STR_OBJ_TYPE = new TypeToken<>() { };
+
+
+    private boolean isItemStack(Map<String, Object> deserializedMap) {
+        return deserializedMap.containsKey(ConfigurationSerialization.SERIALIZED_TYPE_KEY)
+                && deserializedMap.get(ConfigurationSerialization.SERIALIZED_TYPE_KEY) instanceof String serializedType
+                && ItemStack.class.equals(ConfigurationSerialization.getClassByAlias(serializedType));
+    }
+
+    @Override
+    public ConfigurationSerializable deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
+        Map<String, Object> deserializedMap = context.deserialize(json, MAP_STR_OBJ_TYPE.getType());
+        if (isItemStack(deserializedMap)) {
+            ItemStackAdapter.fixDeserializationVersion(deserializedMap);
+        }
+        return ConfigurationSerialization.deserializeObject(deserializedMap);
+    }
+
+    @Override
+    public JsonElement serialize(ConfigurationSerializable src, Type typeOfSrc, JsonSerializationContext context) {
+        Map<String, Object> values = new LinkedHashMap<>();
+        values.put(ConfigurationSerialization.SERIALIZED_TYPE_KEY, ConfigurationSerialization.getAlias(src.getClass()));
+        values.putAll(src.serialize());
+        return context.serialize(values, MAP_STR_OBJ_TYPE.getType());
+    }
+}

pandalib-paper/src/main/java/fr/pandacube/lib/paper/json/ItemStackAdapter.java

@@ -25,21 +25,7 @@ import java.util.Map;
     @Override
     public ItemStack deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
         Map<String, Object> deserializedMap = context.deserialize(json, MAP_STR_OBJ_TYPE.getType());
-        int itemStackVersion = deserializedMap.containsKey("v") ? ((Number)deserializedMap.get("v")).intValue() : -1;
+        fixDeserializationVersion(deserializedMap);
-        if (itemStackVersion >= 0) {
-            @SuppressWarnings("deprecation")
-            int currentDataVersion = Bukkit.getUnsafe().getDataVersion();
-            if (itemStackVersion > currentDataVersion) {
-                /* The itemStack we are deserializing is from a newer MC version, so Bukkit will refuse it.
-                 * We decide to ignore the provided version and consider that the received item stack is from current
-                 * version. We let Bukkit handles the deserialization with the data it can interpret, throwing an error
-                 * only if it can't.
-                 */
-                deserializedMap.put("v", currentDataVersion);
-                return ItemStack.deserialize(deserializedMap);
-            }
-        }
-
         return ItemStack.deserialize(deserializedMap);
     }
 
@@ -47,4 +33,24 @@ import java.util.Map;
     public JsonElement serialize(ItemStack src, Type typeOfSrc, JsonSerializationContext context) {
         return context.serialize(src.serialize(), MAP_STR_OBJ_TYPE.getType());
     }
+
+
+
+    /* package */ static void fixDeserializationVersion(Map<String, Object> deserializedMap) {
+        if (!deserializedMap.containsKey("v"))
+            return;
+        int itemStackVersion = ((Number)deserializedMap.get("v")).intValue();
+        if (itemStackVersion >= 0) {
+            @SuppressWarnings("deprecation")
+            int currentDataVersion = Bukkit.getUnsafe().getDataVersion();
+            if (itemStackVersion > currentDataVersion) {
+                /* Here, the itemStack we are deserializing is from a newer MC version, so Bukkit will refuse it.
+                 * We decide to ignore the provided version and consider that the received item stack is from current
+                 * version. We let Bukkit handles the deserialization with the data it can interpret, throwing an error
+                 * only if it can't.
+                 */
+                deserializedMap.put("v", currentDataVersion);
+            }
+        }
+    }
 }

pandalib-paper/src/main/java/fr/pandacube/lib/paper/json/PaperJson.java

@@ -12,5 +12,6 @@ public class PaperJson {
      */
     public static void init() {
         Json.registerTypeAdapterFactory(ItemStackAdapter.FACTORY);
+        Json.registerTypeAdapterFactory(ConfigurationSerializableAdapter.FACTORY);
     }
 }