1 /*
2  * Copyright (C) 2022 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 com.android.settingslib.spa.framework.util
18 
19 import androidx.compose.runtime.Composable
20 import androidx.compose.runtime.LaunchedEffect
21 import kotlinx.coroutines.flow.MutableStateFlow
22 import kotlinx.coroutines.flow.filterNotNull
23 
24 /** A StateFlow holder which value could be set or sync from callback. */
25 class StateFlowBridge<T> {
26     private val stateFlow = MutableStateFlow<T?>(null)
27     val flow = stateFlow.filterNotNull()
28 
setIfAbsentnull29     fun setIfAbsent(value: T) {
30         if (stateFlow.value == null) {
31             stateFlow.value = value
32         }
33     }
34 
35     @Composable
Syncnull36     fun Sync(callback: () -> T) {
37         val value = callback()
38         LaunchedEffect(value) {
39             stateFlow.value = value
40         }
41     }
42 }
43