1 files changed, 36 insertions, 0 deletions
diff --git a/src/main/kotlin/moe/nea/firmament/util/json/SingletonSerializableList.kt b/src/main/kotlin/moe/nea/firmament/util/json/SingletonSerializableList.kt
new file mode 100644
index 0000000..5474b35
--- /dev/null
+++ b/src/main/kotlin/moe/nea/firmament/util/json/SingletonSerializableList.kt
@@ -0,0 +1,36 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.util.json
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.builtins.ListSerializer
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.json.JsonArray
+import kotlinx.serialization.json.JsonDecoder
+import kotlinx.serialization.json.JsonElement
+
+class SingletonSerializableList<T>(val child: KSerializer<T>) : KSerializer<List<T>> {
+    override val descriptor: SerialDescriptor
+        get() = JsonElement.serializer().descriptor
+
+    override fun deserialize(decoder: Decoder): List<T> {
+        decoder as JsonDecoder
+        val list = JsonElement.serializer().deserialize(decoder)
+        if (list is JsonArray) {
+            return list.map {
+                decoder.json.decodeFromJsonElement(child, it)
+            }
+        }
+        return listOf(decoder.json.decodeFromJsonElement(child, list))
+    }
+
+    override fun serialize(encoder: Encoder, value: List<T>) {
+        ListSerializer(child).serialize(encoder, value)
+    }
+}