1 /*
2  * Copyright 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package androidx.datastore.core
18 
19 /**
20  * The initializer API allows changes to be made to store before data is accessed through data or
21  * updateData.
22  *
23  * Initializers are executed in the order in which they are added. They must be idempotent since
24  * they are run each time the DataStore starts, and they may be run multiple times by a single
25  * instance if a downstream initializer fails.
26  *
27  * Note: Initializers are internal only. Instead, see [DataMigration].
28  */
29 internal interface InitializerApi<T> {
updateDatanull30     suspend fun updateData(transform: suspend (t: T) -> T): T
31 }
32