Fix Scheme special meta implementation

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/MutableMeta.kt

@@ -265,14 +265,7 @@ public operator fun <M : MutableTypedMeta<M>> MutableTypedMeta<M>.set(name: Name
 private class MutableMetaImpl(
     value: Value?,
     children: Map<NameToken, Meta> = emptyMap()
-) : ObservableMutableMeta {
+) : AbstractObservableMeta(), ObservableMutableMeta {
-
-    private val listeners = HashSet<MetaListener>()
-
-    override fun invalidate(name: Name) {
-        listeners.forEach { it.callback(this, name) }
-    }
-
     override var value = value
         @Synchronized set(value) {
             val oldValue = field
@@ -289,17 +282,6 @@ private class MutableMetaImpl(
 
     override val items: Map<NameToken, ObservableMutableMeta> get() = children
 
-
-    @Synchronized
-    override fun onChange(owner: Any?, callback: Meta.(name: Name) -> Unit) {
-        listeners.add(MetaListener(owner, callback))
-    }
-
-    @Synchronized
-    override fun removeListener(owner: Any?) {
-        listeners.removeAll { it.owner === owner }
-    }
-
     private fun ObservableMeta.adoptBy(parent: MutableMetaImpl, key: NameToken) {
         onChange(parent) { name ->
             parent.invalidate(key + name)
@@ -377,10 +359,6 @@ private class MutableMetaImpl(
             invalidate(name)
         }
     }
-
-    override fun toString(): String = Meta.toString(this)
-    override fun equals(other: Any?): Boolean = Meta.equals(this, other as? Meta)
-    override fun hashCode(): Int = Meta.hashCode(this)
 }
 
 /**

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableMeta.kt

@@ -1,8 +1,6 @@
 package space.kscience.dataforge.meta
 
-import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.*
-import space.kscience.dataforge.values.Value
 import kotlin.jvm.Synchronized
 import kotlin.reflect.KProperty1
 
@@ -38,7 +36,6 @@ public interface ObservableMeta : Meta {
 public interface ObservableMutableMeta : ObservableMeta, MutableMeta, MutableTypedMeta<ObservableMutableMeta> {
     override fun getOrCreate(name: Name): ObservableMutableMeta
 
-
     override fun getMeta(name: Name): ObservableMutableMeta? {
         tailrec fun ObservableMutableMeta.find(name: Name): ObservableMutableMeta? = if (name.isEmpty()) {
             this
@@ -50,10 +47,7 @@ public interface ObservableMutableMeta : ObservableMeta, MutableMeta, MutableTyp
     }
 }
 
-private class ObservableMetaWrapper(
+internal abstract class AbstractObservableMeta : ObservableMeta {
-    val origin: MutableMeta,
-) : ObservableMutableMeta, Meta by origin {
-
     private val listeners = HashSet<MetaListener>()
 
     override fun invalidate(name: Name) {
@@ -70,58 +64,11 @@ private class ObservableMetaWrapper(
         listeners.removeAll { it.owner === owner }
     }
 
-    override val items: Map<NameToken, ObservableMetaWrapper>
+    override fun toString(): String = Meta.toString(this)
-        get() = origin.items.mapValues { ObservableMetaWrapper(it.value) }
+    override fun equals(other: Any?): Boolean = Meta.equals(this, other as? Meta)
-
+    override fun hashCode(): Int = Meta.hashCode(this)
-    override fun getMeta(name: Name): ObservableMetaWrapper? = origin.getMeta(name)?.let{ObservableMetaWrapper(it)}
-
-    override var value: Value?
-        get() = origin.value
-        set(value) {
-            origin.value = value
-            invalidate(Name.EMPTY)
 }
 
-    override fun getOrCreate(name: Name): ObservableMutableMeta =
-        get(name) ?: ObservableMetaWrapper(origin.getOrCreate(name))
-
-    override fun setMeta(name: Name, node: Meta?) {
-        val oldMeta = get(name)
-        origin.setMeta(name, node)
-        //
-        // if meta is observable propagate changes from it
-        if (node is ObservableMeta) {
-
-            node.onChange(this) { changeName ->
-                setMeta(name + changeName, node[changeName])
-            }
-        }
-        if (oldMeta != node) {
-            invalidate(name)
-        }
-    }
-
-    override fun toMeta(): Meta {
-        return origin.toMeta()
-    }
-
-    @DFExperimental
-    override fun attach(name: Name, node: ObservableMutableMeta) {
-        set(name, node)
-        node.onChange(this) { changeName ->
-            setMeta(name + changeName, node[changeName])
-        }
-    }
-}
-
-/**
- * Cast this [MutableMeta] to [ObservableMutableMeta] or create an observable wrapper. Only changes made to the result
- * are guaranteed to be observed.
- */
-public fun MutableMeta.asObservable(): ObservableMutableMeta =
-    (this as? ObservableMutableMeta) ?: ObservableMetaWrapper(this)
-
-
 /**
  * Use the value of the property in a [callBack].
  * The callback is called once immediately after subscription to pass the initial value.

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableMetaWrapper.kt

@@ -0,0 +1,82 @@
+package space.kscience.dataforge.meta
+
+import space.kscience.dataforge.misc.DFExperimental
+import space.kscience.dataforge.names.*
+import space.kscience.dataforge.values.Value
+import kotlin.jvm.Synchronized
+
+/**
+ * A class that takes [MutableMeta] provider and adds obsevability on top of that
+ */
+private class ObservableMetaWrapper(
+    val root: MutableMeta,
+    val absoluteName: Name,
+    val listeners: MutableSet<MetaListener>
+) : ObservableMutableMeta {
+    override val items: Map<NameToken, ObservableMutableMeta>
+        get() = root.items.mapValues {
+            ObservableMetaWrapper(root, absoluteName + it.key, listeners)
+        }
+
+    override fun getMeta(name: Name): ObservableMutableMeta? =
+        root.getMeta(name)?.let { ObservableMetaWrapper(root, this.absoluteName + name, listeners) }
+
+    @Synchronized
+    override fun onChange(owner: Any?, callback: Meta.(name: Name) -> Unit) {
+        listeners.add(
+            MetaListener(Pair(owner, absoluteName)) { name ->
+                if (name.startsWith(absoluteName)) {
+                    (this[absoluteName] ?: Meta.EMPTY).callback(name.removeHeadOrNull(absoluteName)!!)
+                }
+            }
+        )
+    }
+
+    override fun removeListener(owner: Any?) {
+        listeners.removeAll { it.owner === Pair(owner, absoluteName) }
+    }
+
+    override fun invalidate(name: Name) {
+        listeners.forEach { it.callback(this, name) }
+    }
+
+    override var value: Value?
+        get() = root.value
+        set(value) {
+            root.value = value
+            invalidate(Name.EMPTY)
+        }
+
+    override fun getOrCreate(name: Name): ObservableMutableMeta =
+        ObservableMetaWrapper(root, this.absoluteName + name, listeners)
+
+    override fun setMeta(name: Name, node: Meta?) {
+        val oldMeta = get(name)
+        root.setMeta(absoluteName + name, node)
+        if (oldMeta != node) {
+            invalidate(name)
+        }
+    }
+
+    override fun toMeta(): Meta = root[absoluteName]?.toMeta() ?: Meta.EMPTY
+
+    override fun toString(): String = Meta.toString(this)
+    override fun equals(other: Any?): Boolean = Meta.equals(this, other as? Meta)
+    override fun hashCode(): Int = Meta.hashCode(this)
+
+    @DFExperimental
+    override fun attach(name: Name, node: ObservableMutableMeta) {
+        set(name, node)
+        node.onChange(this) { changeName ->
+            setMeta(name + changeName, node[changeName])
+        }
+    }
+}
+
+
+/**
+ * Cast this [MutableMeta] to [ObservableMutableMeta] or create an observable wrapper. Only changes made to the result
+ * are guaranteed to be observed.
+ */
+public fun MutableMeta.asObservable(): ObservableMutableMeta =
+    (this as? ObservableMutableMeta) ?: ObservableMetaWrapper(this, Name.EMPTY, hashSetOf())

dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt

@@ -1,8 +1,10 @@
 package space.kscience.dataforge.meta
 
 import space.kscience.dataforge.meta.descriptors.*
-import space.kscience.dataforge.names.Name
+import space.kscience.dataforge.misc.DFExperimental
+import space.kscience.dataforge.names.*
 import space.kscience.dataforge.values.Value
+import kotlin.jvm.Synchronized
 
 /**
  * A base for delegate-based or descriptor-based scheme. [Scheme] has an empty constructor to simplify usage from [Specification].
@@ -10,19 +12,23 @@ import space.kscience.dataforge.values.Value
  */
 public open class Scheme : Described, MetaRepr, MutableMetaProvider, Configurable {
 
-    private var _meta = MutableMeta()
+    private var targetMeta: MutableMeta = MutableMeta()
 
-    final override val meta: ObservableMutableMeta get() = _meta
+    private var defaultMeta: Meta? = null
 
-    internal var metaDescriptor: MetaDescriptor? = null
+    final override val meta: ObservableMutableMeta = SchemeMeta(Name.EMPTY)
 
-    final override val descriptor: MetaDescriptor? get() = metaDescriptor
+    final override var descriptor: MetaDescriptor? = null
+        internal set
 
     internal fun wrap(
-        items: MutableMeta,
+        newMeta: MutableMeta,
         preserveDefault: Boolean = false
     ) {
-        _meta = (if (preserveDefault) items.withDefault(meta.seal()) else items).asObservable()
+        if(preserveDefault){
+            defaultMeta = targetMeta.seal()
+        }
+        targetMeta = newMeta
     }
 
     /**
@@ -44,11 +50,70 @@ public open class Scheme : Described, MetaRepr, MutableMetaProvider, Configurabl
     }
 
     override fun setValue(name: Name, value: Value?) {
-        //TODO add validation
+        val valueDescriptor = descriptor?.get(name)
+        if (valueDescriptor?.validate(value) != false) {
             meta.setValue(name, value)
+        } else error("Value $value is not validated by $valueDescriptor")
     }
 
     override fun toMeta(): Laminate = Laminate(meta, descriptor?.defaultNode)
+
+    private val listeners = HashSet<MetaListener>()
+
+    private inner class SchemeMeta(val pathName: Name) : ObservableMutableMeta {
+        override var value: Value?
+            get() = targetMeta[pathName]?.value ?: defaultMeta?.get(pathName)?.value
+            set(value) {
+                val oldValue = targetMeta[pathName]?.value
+                targetMeta[pathName] = value
+                if (oldValue != value) {
+                    invalidate(pathName)
+                }
+            }
+
+        override val items: Map<NameToken, ObservableMutableMeta>
+            get() {
+                val targetKeys = targetMeta[pathName]?.items?.keys ?: emptySet()
+                val defaultKeys = defaultMeta?.get(pathName)?.items?.keys ?: emptySet()
+                return (targetKeys + defaultKeys).associateWith { SchemeMeta(pathName + it) }
+            }
+
+        override fun invalidate(name: Name) {
+            listeners.forEach { it.callback(this@Scheme.meta, pathName + name) }
+        }
+
+        @Synchronized
+        override fun onChange(owner: Any?, callback: Meta.(name: Name) -> Unit) {
+            listeners.add(MetaListener(owner) { changedeName ->
+                if (changedeName.startsWith(pathName)) {
+                    this@Scheme.meta.callback(changedeName.removeHeadOrNull(pathName)!!)
+                }
+            })
+        }
+
+        @Synchronized
+        override fun removeListener(owner: Any?) {
+            listeners.removeAll { it.owner === owner }
+        }
+
+        override fun toString(): String = Meta.toString(this)
+        override fun equals(other: Any?): Boolean = Meta.equals(this, other as? Meta)
+        override fun hashCode(): Int = Meta.hashCode(this)
+
+        override fun setMeta(name: Name, node: Meta?) {
+            targetMeta.setMeta(name, node)
+            invalidate(name)
+        }
+
+        override fun getOrCreate(name: Name): ObservableMutableMeta = SchemeMeta(pathName + name)
+
+        @DFExperimental
+        override fun attach(name: Name, node: ObservableMutableMeta) {
+            TODO("Not yet implemented")
+        }
+
+
+    }
 }
 
 /**
@@ -83,7 +148,7 @@ public open class SchemeSpec<out T : Scheme>(
     override val descriptor: MetaDescriptor? get() = null
 
     override fun empty(): T = builder().also {
-        it.metaDescriptor = descriptor
+        it.descriptor = descriptor
     }
 
     @Suppress("OVERRIDE_BY_INLINE")