[WIP] initial Fabric port

major package refactoring

src/main/kotlin/mods/betterfoliage/util/Caching.kt

@@ -0,0 +1,60 @@
+package mods.betterfoliage.util
+
+import java.lang.ref.WeakReference
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+interface Invalidator {
+    fun invalidate() {
+        val iterator = callbacks.iterator()
+        while(iterator.hasNext()) iterator.next().let { callback ->
+            callback.get()?.invoke() ?: iterator.remove()
+        }
+    }
+    val callbacks: MutableList<WeakReference<()->Unit>>
+    fun onInvalidate(callback: ()->Unit) {
+        callbacks.add(WeakReference(callback))
+    }
+}
+
+class LazyInvalidatable<V>(invalidator: Invalidator, val valueFactory: ()->V): ReadOnlyProperty<Any, V> {
+    init { invalidator.onInvalidate { value = null } }
+
+    var value: V? = null
+
+    override fun getValue(thisRef: Any, property: KProperty<*>): V {
+        value?.let { return it }
+        return synchronized(this) {
+            value?.let { return it }
+            valueFactory().apply { value = this }
+        }
+    }
+}
+
+class LazyMap<K, V>(val invalidator: Invalidator, val valueFactory: (K)->V) {
+    init { invalidator.onInvalidate { values.clear() } }
+
+    val values = mutableMapOf<K, V>()
+
+    operator fun get(key: K): V {
+        values[key]?.let { return it }
+        return synchronized(values) {
+            values[key]?.let { return it }
+            valueFactory(key).apply { values[key] = this }
+        }
+    }
+    operator fun set(key: K, value: V) { values[key] = value }
+
+    fun delegate(key: K) = Delegate(key)
+
+    inner class Delegate(val key: K) : ReadOnlyProperty<Any, V> {
+        init { invalidator.onInvalidate { cached = null } }
+
+        private var cached: V? = null
+
+        override fun getValue(thisRef: Any, property: KProperty<*>): V {
+            cached?.let { return it }
+            get(key).let { cached = it; return it }
+        }
+    }
+}