| rohitsat13 | 5fe0a26 | 2021-02-19 09:28:47 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2021 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.preferences.rxjava2 |
| 18 | |
| 19 | import android.content.Context |
| 20 | import androidx.annotation.GuardedBy |
| 21 | import androidx.datastore.core.DataMigration |
| 22 | import androidx.datastore.core.handlers.ReplaceFileCorruptionHandler |
| 23 | import androidx.datastore.preferences.core.Preferences |
| 24 | import androidx.datastore.rxjava2.RxDataStore |
| 25 | import io.reactivex.Scheduler |
| 26 | import io.reactivex.schedulers.Schedulers |
| 27 | import kotlin.properties.ReadOnlyProperty |
| 28 | import kotlin.reflect.KProperty |
| 29 | |
| 30 | /** |
| 31 | * Creates a property delegate for a single process Preferences DataStore. This should only be |
| 32 | * called once |
| 33 | * in a file (at the top level), and all usages of the DataStore should use a reference the same |
| 34 | * Instance. The receiver type for the property delegate must be an instance of [Context]. |
| 35 | * |
| 36 | * Example usage: |
| 37 | * ``` |
| 38 | * val Context.myRxDataStore by rxPreferencesDataStore("filename", serializer) |
| 39 | * |
| 40 | * class SomeClass(val context: Context) { |
| 41 | * fun update(): Single<Preferences> = context.myRxDataStore.updateDataAsync {...} |
| 42 | * } |
| 43 | * ``` |
| 44 | * |
| 45 | * |
| 46 | * @param name The name of the preferences. The preferences will be stored in a file obtained |
| 47 | * by calling: File(context.filesDir, "datastore/" + name + ".preferences_pb") |
| 48 | * @param corruptionHandler The corruptionHandler is invoked if DataStore encounters a |
| 49 | * [androidx.datastore.core.CorruptionException] when attempting to read data. CorruptionExceptions |
| 50 | * are thrown by serializers when data can not be de-serialized. |
| 51 | * @param migrations are run before any access to data can occur. Each producer and migration |
| 52 | * may be run more than once whether or not it already succeeded (potentially because another |
| 53 | * migration failed or a write to disk failed.) |
| 54 | * @param scheduler The scope in which IO operations and transform functions will execute. |
| 55 | * |
| 56 | * @return a property delegate that manages a datastore as a singleton. |
| 57 | */ |
| 58 | @JvmOverloads |
| 59 | public fun rxPreferencesDataStore( |
| 60 | name: String, |
| 61 | corruptionHandler: ReplaceFileCorruptionHandler<Preferences>? = null, |
| 62 | migrations: List<DataMigration<Preferences>> = listOf(), |
| 63 | scheduler: Scheduler = Schedulers.io() |
| 64 | ): ReadOnlyProperty<Context, RxDataStore<Preferences>> { |
| 65 | return RxDataStoreSingletonDelegate(name, corruptionHandler, migrations, scheduler) |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * Delegate class to manage DataStore as a singleton. |
| 70 | */ |
| 71 | internal class RxDataStoreSingletonDelegate internal constructor( |
| 72 | private val fileName: String, |
| 73 | private val corruptionHandler: ReplaceFileCorruptionHandler<Preferences>?, |
| 74 | private val migrations: List<DataMigration<Preferences>>, |
| 75 | private val scheduler: Scheduler |
| 76 | ) : ReadOnlyProperty<Context, RxDataStore<Preferences>> { |
| 77 | |
| 78 | private val lock = Any() |
| 79 | |
| 80 | @GuardedBy("lock") |
| 81 | @Volatile |
| 82 | private var INSTANCE: RxDataStore<Preferences>? = null |
| 83 | |
| 84 | /** |
| 85 | * Gets the instance of the DataStore. |
| 86 | * |
| 87 | * @param thisRef must be an instance of [Context] |
| 88 | * @param property not used |
| 89 | */ |
| 90 | override fun getValue(thisRef: Context, property: KProperty<*>): RxDataStore<Preferences> { |
| 91 | return INSTANCE ?: synchronized(lock) { |
| 92 | if (INSTANCE == null) { |
| 93 | INSTANCE = with(RxPreferenceDataStoreBuilder(thisRef, fileName)) { |
| 94 | setIoScheduler(scheduler) |
| 95 | migrations.forEach { addDataMigration(it) } |
| 96 | corruptionHandler?.let { setCorruptionHandler(it) } |
| 97 | build() |
| 98 | } |
| 99 | } |
| 100 | INSTANCE!! |
| 101 | } |
| 102 | } |
| 103 | } |