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Compose components that allow saving and restoring the local ui state

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/*
 * Copyright 2021 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.runtime.saveable

/**
 * The [Saver] implementation which allows to represent your [Original] class as a list of
 * [Saveable] values.
 *
 * What types can be saved is defined by [SaveableStateRegistry], by default everything which can be
 * stored in the Bundle class can be saved.
 *
 * You can use it as a parameter for [rememberSaveable].
 *
 * @sample androidx.compose.runtime.saveable.samples.ListSaverSample
 */
fun  listSaver(
    save: SaverScope.(value: Original) -> List,
    restore: (list: List) -> Original?
): Saver =
    @Suppress("UNCHECKED_CAST")
    Saver(
        save = {
            val list = save(it)
            for (index in list.indices) {
                val item = list[index]
                if (item != null) {
                    require(canBeSaved(item)) { "item can't be saved" }
                }
            }
            if (list.isNotEmpty()) ArrayList(list) else null
        },
        restore = restore as (Any) -> Original?
    )