1 /* 2 * Copyright (C) 2024 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.systemui.kairos.internal 18 19 import com.android.systemui.kairos.util.Just 20 import kotlin.coroutines.CoroutineContext 21 import kotlin.coroutines.EmptyCoroutineContext 22 23 internal class Output<A>( 24 val context: CoroutineContext = EmptyCoroutineContext, <lambda>null25 val onDeath: suspend () -> Unit = {}, 26 val onEmit: suspend EvalScope.(A) -> Unit, 27 ) { 28 29 val schedulable = Schedulable.O(this) 30 31 @Volatile var upstream: NodeConnection<A>? = null 32 @Volatile var result: Any? = NoResult 33 34 private object NoResult 35 36 // invoked by network visitnull37 suspend fun visit(evalScope: EvalScope) { 38 val upstreamResult = result 39 check(upstreamResult !== NoResult) { "output visited with null upstream result" } 40 result = null 41 @Suppress("UNCHECKED_CAST") evalScope.onEmit(upstreamResult as A) 42 } 43 killnull44 suspend fun kill() { 45 onDeath() 46 } 47 schedulenull48 suspend fun schedule(evalScope: EvalScope) { 49 val upstreamResult = 50 checkNotNull(upstream) { "output scheduled with null upstream" }.getPushEvent(evalScope) 51 if (upstreamResult is Just) { 52 result = upstreamResult.value 53 evalScope.scheduleOutput(this) 54 } 55 } 56 } 57 OneShotnull58internal inline fun OneShot(crossinline onEmit: suspend EvalScope.() -> Unit): Output<Unit> = 59 Output<Unit>(onEmit = { onEmit() }).apply { result = Unit } 60