| /* |
| * Copyright 2019 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.compose |
| |
| /** |
| * A StaticValueHolder holds a value that will never change. |
| */ |
| internal data class StaticValueHolder<T>(override val value: T) : State<T> |
| |
| /** |
| * A lazy value holder is static value holder for which the value is produced by the valueProducer |
| * parameter which is called once and the result is remembered for the life of LazyValueHolder. |
| */ |
| internal class LazyValueHolder<T>(valueProducer: (() -> T)?) : State<T> { |
| @Suppress("UNCHECKED_CAST") |
| private val current by lazy { |
| val fn = valueProducer |
| if (fn == null) null as T |
| else fn() |
| } |
| |
| override val value: T get() = current |
| } |