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