ReplaceFileCorruptionHandler.kt

/*
 * Copyright 2020 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.datastore.core.handlers

import androidx.datastore.core.CorruptionException
import androidx.datastore.core.CorruptionHandler
import java.io.IOException
import kotlin.jvm.Throws

/**
 * A corruption handler that attempts to replace the on-disk data with data from produceNewData.
 *
 * If the handler successfully replaces the data, the original exception is swallowed.
 * If the handler encounters an exception when attempting to replace data, the new exception is
 * added as a suppressed exception to the original exception and the original exception is thrown.
 *
 * @param produceNewData The provided callback returns the data to be written to disk. If the
 * callback fails, nothing will be written to disk. Since the exception will be swallowed after
 * writing the data, this is a good place to log the exception.
 */
public class ReplaceFileCorruptionHandler<T>(
    private val produceNewData: (CorruptionException) -> T
) : CorruptionHandler<T> {

    @Throws(IOException::class)
    override suspend fun handleCorruption(ex: CorruptionException): T {
        return produceNewData(ex)
    }
}