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 package com.example.tracing.demo.experiments 17 18 import com.android.app.tracing.coroutines.flow.collectTraced as collect 19 import com.android.app.tracing.coroutines.flow.collectTraced 20 import com.android.app.tracing.coroutines.flow.filterTraced as filter 21 import com.android.app.tracing.coroutines.flow.flowName 22 import com.android.app.tracing.coroutines.flow.mapTraced as map 23 import com.android.app.tracing.coroutines.flow.stateInTraced 24 import com.android.app.tracing.coroutines.launchTraced as launch 25 import com.android.app.tracing.coroutines.traceCoroutine 26 import com.example.tracing.demo.FixedThread1 27 import com.example.tracing.demo.FixedThread2 28 import com.example.tracing.demo.FixedThread3 29 import com.example.tracing.demo.FixedThread4 30 import javax.inject.Inject 31 import javax.inject.Singleton 32 import kotlinx.coroutines.CoroutineDispatcher 33 import kotlinx.coroutines.coroutineScope 34 import kotlinx.coroutines.flow.SharingStarted 35 import kotlinx.coroutines.flow.flow 36 import kotlinx.coroutines.flow.flowOn 37 38 @Singleton 39 class SharedFlowUsage 40 @Inject 41 constructor( 42 @FixedThread1 private var dispatcher1: CoroutineDispatcher, 43 @FixedThread2 private var dispatcher2: CoroutineDispatcher, 44 @FixedThread3 private var dispatcher3: CoroutineDispatcher, 45 @FixedThread4 private var dispatcher4: CoroutineDispatcher, 46 ) : TracedExperiment() { 47 48 override val description: String = "Create a shared flow and collect from it" 49 50 private val coldFlow = <lambda>null51 flow { 52 var n = 0 53 while (n < 20) { 54 emit(n++) 55 forceSuspend(timeMillis = 5) 56 } 57 } <lambda>null58 .map("pow2") { 59 val rv = it * it 60 forceSuspend("map($it) -> $rv", 50) 61 rv 62 } 63 // this trace name is used here because the dispatcher changed 64 .flowOn(dispatcher3) <lambda>null65 .filter("mod4") { 66 val rv = it % 4 == 0 67 forceSuspend("filter($it) -> $rv", 50) 68 rv 69 } 70 .flowName("COLD_FLOW") 71 <lambda>null72 override suspend fun runExperiment(): Unit = coroutineScope { 73 val stateFlow = coldFlow.stateInTraced("My-StateFlow", this, SharingStarted.Eagerly, 10) 74 launch("launchAAAA", dispatcher1) { 75 stateFlow.collect("collectAAAA") { 76 traceCoroutine("AAAA collected: $it") { forceSuspend("AAAA", 15) } 77 } 78 } 79 launch("launchBBBB", dispatcher2) { 80 // Don't pass a string. Instead, rely on default behavior to walk the stack for the 81 // name. This results in trace sections like: 82 // `collect:SharedFlowUsage$start$1$2:emit` 83 // NOTE: `Flow.collect` is a member function and takes precedence, so we need 84 // to invoke `collectTraced` using its original name instead of its `collect` alias 85 stateFlow.collectTraced { 86 traceCoroutine("BBBB collected: $it") { forceSuspend("BBBB", 30) } 87 } 88 } 89 launch("launchCCCC", dispatcher3) { 90 stateFlow.collect("collectCCCC") { 91 traceCoroutine("CCCC collected: $it") { forceSuspend("CCCC", 60) } 92 } 93 } 94 launch("launchDDDD", dispatcher4) { 95 // Uses Flow.collect member function instead of collectTraced: 96 stateFlow.collect { traceCoroutine("DDDD collected: $it") { forceSuspend("DDDD", 90) } } 97 } 98 } 99 } 100