Add KeyValueStore interface

/*

 * Copyright (C) 2024 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 com.android.settingslib.datastore

import android.content.SharedPreferences

/** Interface of key-value store. */

interface KeyValueStore {

    /** Returns if the storage contains persistent value of given key. */

    fun contains(key: String): Boolean

    /** Gets default value of given key. */

    fun <T : Any> getDefaultValue(key: String, valueType: Class<T>): T? =

        when (valueType) {

            Boolean::class.javaObjectType -> false

            Float::class.javaObjectType -> 0f

            Int::class.javaObjectType -> 0

            Long::class.javaObjectType -> 0

            else -> null

        }

            as T?

    /** Gets value of given key. */

    fun <T : Any> getValue(key: String, valueType: Class<T>): T?

    /**

     * Sets value for given key.

     *

     * @param key key

     * @param valueType value type

     * @param value value to set, null means remove

     */

    fun <T : Any> setValue(key: String, valueType: Class<T>, value: T?)

}

/** [SharedPreferences] based [KeyValueStore]. */

interface SharedPreferencesKeyValueStore : KeyValueStore {

    /** [SharedPreferences] of the key-value store. */

    val sharedPreferences: SharedPreferences

    override fun contains(key: String): Boolean = sharedPreferences.contains(key)

    override fun <T : Any> getValue(key: String, valueType: Class<T>): T? =

        when (valueType) {

            Boolean::class.javaObjectType -> sharedPreferences.getBoolean(key, false)

            Float::class.javaObjectType -> sharedPreferences.getFloat(key, 0f)

            Int::class.javaObjectType -> sharedPreferences.getInt(key, 0)

            Long::class.javaObjectType -> sharedPreferences.getLong(key, 0)

            String::class.javaObjectType -> sharedPreferences.getString(key, null)

            Set::class.javaObjectType -> sharedPreferences.getStringSet(key, null)

            else -> null

        }

            as T?

    override fun <T : Any> setValue(key: String, valueType: Class<T>, value: T?) {

        if (value == null) {

            sharedPreferences.edit().remove(key).apply()

            return

        }

        val edit = sharedPreferences.edit()

        when (valueType) {

            Boolean::class.javaObjectType -> edit.putBoolean(key, value as Boolean)

            Float::class.javaObjectType -> edit.putFloat(key, value as Float)

            Int::class.javaObjectType -> edit.putInt(key, value as Int)

            Long::class.javaObjectType -> edit.putLong(key, value as Long)

            String::class.javaObjectType -> edit.putString(key, value as String)

            Set::class.javaObjectType -> edit.putStringSet(key, value as Set<String>)

            else -> {}

        }

        edit.apply()

    }

}