New Meta serializer

dataforge-io/src/commonTest/kotlin/hep/dataforge/io/MetaSerializerTest.kt

@@ -27,6 +27,7 @@ class MetaSerializerTest {
     @Test
     fun testMetaSerialization() {
         val string = JSON_PRETTY.encodeToString(MetaSerializer, meta)
+        println(string)
         val restored = JSON_PLAIN.decodeFromString(MetaSerializer, string)
         assertEquals(meta, restored)
     }
@@ -35,7 +36,7 @@ class MetaSerializerTest {
     @Test
     fun testCborSerialization() {
         val bytes = Cbor.encodeToByteArray(MetaSerializer, meta)
-        println(bytes.contentToString())
+        println(bytes.decodeToString())
         val restored = Cbor.decodeFromByteArray(MetaSerializer, bytes)
         assertEquals(meta, restored)
     }

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Config.kt

@@ -28,8 +28,8 @@ public interface ObservableMeta : Meta {
 /**
  * Mutable meta representing object state
  */
-@Serializable
+@Serializable(Config.Companion::class)
-public class Config : AbstractMutableMeta<Config>(), ObservableMeta {
+public class Config() : AbstractMutableMeta<Config>(), ObservableMeta {
 
     private val listeners = HashSet<MetaListener>()
 

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Meta.kt

@@ -4,14 +4,11 @@ import hep.dataforge.meta.Meta.Companion.VALUE_KEY
 import hep.dataforge.meta.MetaItem.NodeItem
 import hep.dataforge.meta.MetaItem.ValueItem
 import hep.dataforge.names.*
-import hep.dataforge.values.*
+import hep.dataforge.values.EnumValue
-import kotlinx.serialization.ExperimentalSerializationApi
+import hep.dataforge.values.Null
-import kotlinx.serialization.KSerializer
+import hep.dataforge.values.Value
+import hep.dataforge.values.boolean
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.Serializer
-import kotlinx.serialization.descriptors.SerialDescriptor
-import kotlinx.serialization.encoding.Decoder
-import kotlinx.serialization.encoding.Encoder
 import kotlinx.serialization.json.Json
 
 
@@ -20,29 +17,17 @@ import kotlinx.serialization.json.Json
  * * a [ValueItem] (leaf)
  * * a [NodeItem] (node)
  */
-@Serializable
+@Serializable(MetaItemSerializer::class)
-public sealed class MetaItem<out M : Meta> {
+public sealed class MetaItem<out M : Meta>() {
 
     abstract override fun equals(other: Any?): Boolean
 
     abstract override fun hashCode(): Int
 
-    @Serializable
+    @Serializable(MetaItemSerializer::class)
     public class ValueItem(public val value: Value) : MetaItem<Nothing>() {
         override fun toString(): String = value.toString()
 
-        @OptIn(ExperimentalSerializationApi::class)
-        @Serializer(ValueItem::class)
-        public companion object : KSerializer<ValueItem> {
-            override val descriptor: SerialDescriptor get() = ValueSerializer.descriptor
-
-            override fun deserialize(decoder: Decoder): ValueItem = ValueItem(ValueSerializer.deserialize(decoder))
-
-            override fun serialize(encoder: Encoder, value: ValueItem) {
-                ValueSerializer.serialize(encoder, value.value)
-            }
-        }
-
         override fun equals(other: Any?): Boolean {
             return this.value == (other as? ValueItem)?.value
         }
@@ -52,23 +37,11 @@ public sealed class MetaItem<out M : Meta> {
         }
     }
 
-    @Serializable
+    @Serializable(MetaItemSerializer::class)
-    public class NodeItem<M : Meta>(@Serializable(MetaSerializer::class) public val node: M) : MetaItem<M>() {
+    public class NodeItem<M : Meta>(public val node: M) : MetaItem<M>() {
         //Fixing serializer for node could cause class cast problems, but it should not since Meta descendants are not serializeable
         override fun toString(): String = node.toString()
 
-        @OptIn(ExperimentalSerializationApi::class)
-        @Serializer(NodeItem::class)
-        public companion object : KSerializer<NodeItem<out Meta>> {
-            override val descriptor: SerialDescriptor get() = MetaSerializer.descriptor
-
-            override fun deserialize(decoder: Decoder): NodeItem<*> = NodeItem(MetaSerializer.deserialize(decoder))
-
-            override fun serialize(encoder: Encoder, value: NodeItem<*>) {
-                MetaSerializer.serialize(encoder, value.node)
-            }
-        }
-
         override fun equals(other: Any?): Boolean = node == (other as? NodeItem<*>)?.node
 
         override fun hashCode(): Int = node.hashCode()
@@ -112,7 +85,6 @@ public fun interface ItemProvider {
  *
  *   * Same name siblings are supported via elements with the same [Name] but different queries
  */
-@Serializable(MetaSerializer::class)
 public interface Meta : MetaRepr, ItemProvider {
     /**
      * Top level items of meta tree

dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaSerializer.kt

@@ -1,17 +1,54 @@
 package hep.dataforge.meta
 
 import hep.dataforge.names.NameToken
+import hep.dataforge.values.ValueSerializer
 import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.InternalSerializationApi
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializer
 import kotlinx.serialization.builtins.MapSerializer
-import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.descriptors.*
-import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.*
-import kotlinx.serialization.encoding.Encoder
 import kotlinx.serialization.json.JsonDecoder
 import kotlinx.serialization.json.JsonEncoder
 import kotlinx.serialization.json.JsonObject
 
+@OptIn(ExperimentalSerializationApi::class)
+public object MetaItemSerializer : KSerializer<MetaItem<*>> {
+
+    @OptIn(InternalSerializationApi::class)
+    override val descriptor: SerialDescriptor = buildClassSerialDescriptor("hep.dataforge.meta.MetaItem") {
+        element<Boolean>("isNode")
+        element("content", buildSerialDescriptor("MetaItem.content", PolymorphicKind.SEALED))
+    }
+
+    override fun deserialize(decoder: Decoder): MetaItem<*> {
+        decoder.decodeStructure(descriptor) {
+            //Force strict serialization order
+            require(decodeElementIndex(descriptor) == 0) { "Node flag must be first item serialized" }
+            val isNode = decodeBooleanElement(descriptor, 0)
+            require(decodeElementIndex(descriptor) == 1) { "Missing MetaItem content" }
+            val item = if (isNode) {
+                decodeSerializableElement(descriptor,1, MetaSerializer).asMetaItem()
+            } else {
+                decodeSerializableElement(descriptor,1,ValueSerializer).asMetaItem()
+            }
+            require(decodeElementIndex(descriptor) == CompositeDecoder.DECODE_DONE){"Serialized MetaItem contains additional fields"}
+            return  item
+        }
+    }
+
+    override fun serialize(encoder: Encoder, value: MetaItem<*>) {
+        encoder.encodeStructure(descriptor) {
+            encodeBooleanElement(descriptor, 0, value is MetaItem.NodeItem)
+            when (value) {
+                is MetaItem.ValueItem -> encodeSerializableElement(descriptor, 1, ValueSerializer, value.value)
+                is MetaItem.NodeItem -> encodeSerializableElement(descriptor, 1, MetaSerializer, value.node)
+            }
+        }
+    }
+}
+
 /**
  * Serialized for meta
  */
@@ -19,9 +56,9 @@ import kotlinx.serialization.json.JsonObject
 @Serializer(Meta::class)
 public object MetaSerializer : KSerializer<Meta> {
 
-    private val mapSerializer = MapSerializer(
+    private val mapSerializer: KSerializer<Map<NameToken, MetaItem<Meta>>> = MapSerializer(
-        NameToken.serializer(),
+        NameToken,
-        MetaItem.serializer(MetaSerializer)
+        MetaItemSerializer//MetaItem.serializer(MetaSerializer)
     )
 
     override val descriptor: SerialDescriptor get() = mapSerializer.descriptor

dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/Value.kt

@@ -19,7 +19,6 @@ public enum class ValueType {
  *
  * Value can represent a list of value objects.
  */
-@Serializable(ValueSerializer::class)
 public interface Value {
     /**
      * Get raw value of this value