1 /*
<lambda>null2  * 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.rxjava3
18 
19 import android.annotation.SuppressLint
20 import android.content.Context
21 import androidx.datastore.core.DataMigration
22 import androidx.datastore.migrations.SharedPreferencesMigration
23 import androidx.datastore.migrations.SharedPreferencesView
24 import io.reactivex.rxjava3.core.Single
25 import kotlinx.coroutines.rx3.await
26 
27 @JvmDefaultWithCompatibility
28 /** Client implemented migration interface. */
29 public interface RxSharedPreferencesMigration<T> {
30     /**
31      * Whether or not the migration should be run. This can be used to skip a read from the
32      * SharedPreferences.
33      *
34      * @param currentData the most recently persisted data
35      * @return a Single indicating whether or not the migration should be run.
36      */
37     public fun shouldMigrate(currentData: T): Single<Boolean> {
38         return Single.just(true)
39     }
40 
41     /**
42      * Maps SharedPreferences into T. Implementations should be idempotent since this may be called
43      * multiple times. See [DataMigration.migrate] for more information. The method accepts a
44      * SharedPreferencesView which is the view of the SharedPreferences to migrate from (limited to
45      * [keysToMigrate]) and a T which represent the current data. The function must return the
46      * migrated data.
47      *
48      * If SharedPreferences is empty or does not contain any keys which you specified, this callback
49      * will not run.
50      *
51      * @param sharedPreferencesView the current state of the SharedPreferences
52      * @param currentData the most recently persisted data
53      * @return a Single of the updated data
54      */
55     public fun migrate(
56         sharedPreferencesView: SharedPreferencesView,
57         currentData: T
58     ): Single<T & Any>
59 }
60 
61 /** RxSharedPreferencesMigrationBuilder for the RxSharedPreferencesMigration. */
62 @SuppressLint("TopLevelBuilder")
63 public class RxSharedPreferencesMigrationBuilder<T>
64 /**
65  * Construct a RxSharedPreferencesMigrationBuilder.
66  *
67  * @param context the Context used for getting the SharedPreferences.
68  * @param sharedPreferencesName the name of the SharedPreference from which to migrate.
69  * @param rxSharedPreferencesMigration the user implemented migration for this SharedPreference.
70  */
71 constructor(
72     private val context: Context,
73     private val sharedPreferencesName: String,
74     private val rxSharedPreferencesMigration: RxSharedPreferencesMigration<T>
75 ) {
76 
77     private var keysToMigrate: Set<String>? = null
78 
79     /**
80      * Set the list of keys to migrate. The keys will be mapped to datastore.Preferences with their
81      * same values. If the key is already present in the new Preferences, the key will not be
82      * migrated again. If the key is not present in the SharedPreferences it will not be migrated.
83      *
84      * This method is optional and if keysToMigrate is not set, all keys will be migrated from the
85      * existing SharedPreferences.
86      *
87      * @param keys the keys to migrate
88      * @return this
89      */
90     @Suppress("MissingGetterMatchingBuilder")
setKeysToMigratenull91     public fun setKeysToMigrate(vararg keys: String): RxSharedPreferencesMigrationBuilder<T> =
92         apply {
93             keysToMigrate = setOf(*keys)
94         }
95 
96     /**
97      * Build and return the DataMigration instance.
98      *
99      * @return the DataMigration.
100      */
buildnull101     public fun build(): DataMigration<T> {
102         return if (keysToMigrate == null) {
103             SharedPreferencesMigration(
104                 context = context,
105                 sharedPreferencesName = sharedPreferencesName,
106                 migrate = { spView, curData ->
107                     rxSharedPreferencesMigration.migrate(spView, curData).await()
108                 },
109                 shouldRunMigration = { curData ->
110                     rxSharedPreferencesMigration.shouldMigrate(curData).await()
111                 }
112             )
113         } else {
114             SharedPreferencesMigration(
115                 context = context,
116                 sharedPreferencesName = sharedPreferencesName,
117                 migrate = { spView, curData ->
118                     rxSharedPreferencesMigration.migrate(spView, curData).await()
119                 },
120                 keysToMigrate = keysToMigrate!!,
121                 shouldRunMigration = { curData ->
122                     rxSharedPreferencesMigration.shouldMigrate(curData).await()
123                 }
124             )
125         }
126     }
127 }
128