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Commit ce250df3 authored by Steve Elliott's avatar Steve Elliott
Browse files

[kairos] simplify scope lifetime tracking 

This effectively reverts ag/32952237

The issue here is that it's far too easy to accidentally leak upstream
events, and the benefit isn't that great.

Flag: com.android.systemui.status_bar_mobile_icon_kairos
Bug: 383172066
Test: atest
Change-Id: Ic58e841c2d4f1d1cae27578ca7dbd085925a452b
parent c06ca2ca

packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/KairosNetwork.kt

+9 −3
Original line number Diff line number Diff line
@@ -167,7 +167,7 @@ internal class LocalNetwork( 
    val nameData: NameData,

    private val network: Network,

    private val scope: CoroutineScope,

    private val aliveLazy: Lazy<State<Boolean>>,

    private val deathSignalLazy: Lazy<Events<Any>>,

) : KairosNetwork {



    init {
@@ -208,7 +208,13 @@ internal class LocalNetwork( 
        BuildScopeImpl(

            nameData,

            epoch,

            stateScope = StateScopeImpl(nameData, epoch, evalScope = this, aliveLazy = aliveLazy),

            stateScope =

                StateScopeImpl(

                    nameData,

                    epoch,

                    evalScope = this,

                    deathSignalLazy = deathSignalLazy,

                ),

            coroutineScope = coroutineScope,

        )
@@ -276,7 +282,7 @@ internal constructor(private val network: Network, private val scope: CoroutineS 
        FullNameTag(lazyOf("root"), "launchKairosNetwork"),

        network,

        scope,

        lazyOf(stateOf(true)),

        lazyOf(emptyEvents),

    )



/** Constructs a new [RootKairosNetwork] in the given [CoroutineScope] and [CoalescingPolicy]. */

packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/BuildScopeImpl.kt

+5 −8
Original line number Diff line number Diff line
@@ -39,7 +39,6 @@ import com.android.systemui.kairos.internal.util.childScope 
import com.android.systemui.kairos.internal.util.invokeOnCancel

import com.android.systemui.kairos.internal.util.launchImmediate

import com.android.systemui.kairos.launchEffect

import com.android.systemui.kairos.observeSync

import com.android.systemui.kairos.skipNext

import com.android.systemui.kairos.takeUntil

import com.android.systemui.kairos.util.Maybe
@@ -81,7 +80,7 @@ internal class BuildScopeImpl( 
        get() = coroutineScope.coroutineContext.job



    override val kairosNetwork: LocalNetwork by lazy {

        LocalNetwork(nameData, network, coroutineScope, stateScope.aliveLazy)

        LocalNetwork(nameData, network, coroutineScope, stateScope.deathSignalLazy)

    }



    override fun <T> events(
@@ -312,7 +311,7 @@ internal class BuildScopeImpl( 
                            asyncNameData,

                            network = this@BuildScopeImpl.network,

                            scope = this@newScope,

                            aliveLazy = childStateScope.aliveLazy,

                            deathSignalLazy = childStateScope.deathSignalLazy,

                        )

                    val scope =

                        object : KairosCoroutineScope, CoroutineScope by this@newScope {
@@ -327,7 +326,7 @@ internal class BuildScopeImpl( 
                    nameData,

                    network = this@BuildScopeImpl.network,

                    scope = childScope,

                    aliveLazy = this@BuildScopeImpl.stateScope.aliveLazy,

                    deathSignalLazy = this@BuildScopeImpl.stateScope.deathSignalLazy,

                )

        }
@@ -401,9 +400,7 @@ internal class BuildScopeImpl( 
                        (newCoroutineScope.coroutineContext.job as CompletableJob).complete()

                    }

                )

                observeSync(nameData + "observeLifetime", alive) {

                    if (!it) newCoroutineScope.cancel()

                }

                deathSignal.observeSync(nameData + "observeLifetime") { newCoroutineScope.cancel() }

            }

    }
@@ -437,7 +434,7 @@ private fun EvalScope.reenterBuildScope( 
                outerScope.stateScope.nameData,

                outerScope.stateScope.createdEpoch,

                evalScope = this,

                aliveLazy = outerScope.stateScope.aliveLazy,

                deathSignalLazy = outerScope.stateScope.deathSignalLazy,

            ),

        coroutineScope,

    )

packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/InternalScopes.kt

+1 −2
Original line number Diff line number Diff line
@@ -18,7 +18,6 @@ package com.android.systemui.kairos.internal 


import com.android.systemui.kairos.BuildScope

import com.android.systemui.kairos.Events

import com.android.systemui.kairos.State

import com.android.systemui.kairos.StateScope

import com.android.systemui.kairos.TransactionScope

import com.android.systemui.kairos.util.NameData
@@ -31,7 +30,7 @@ internal interface InitScope { 
internal interface EvalScope : NetworkScope, DeferScope, TransactionScope



internal interface InternalStateScope : EvalScope, StateScope {

    val alive: State<Boolean>

    val deathSignal: Events<Any>



    fun <A> truncateToScope(events: Events<A>, nameData: NameData): Events<A>

}

packages/SystemUI/utils/kairos/src/com/android/systemui/kairos/internal/StateScopeImpl.kt

+17 −37
Original line number Diff line number Diff line
@@ -27,16 +27,13 @@ import com.android.systemui.kairos.State 
import com.android.systemui.kairos.StateInit

import com.android.systemui.kairos.StateScope

import com.android.systemui.kairos.Stateful

import com.android.systemui.kairos.changes

import com.android.systemui.kairos.emptyEvents

import com.android.systemui.kairos.groupByKey

import com.android.systemui.kairos.init

import com.android.systemui.kairos.map

import com.android.systemui.kairos.mapCheap

import com.android.systemui.kairos.mapCheapUnsafe

import com.android.systemui.kairos.mergeLeft

import com.android.systemui.kairos.skipNext

import com.android.systemui.kairos.switchEvents

import com.android.systemui.kairos.switchEventsPromptly

import com.android.systemui.kairos.util.Maybe

import com.android.systemui.kairos.util.NameData

import com.android.systemui.kairos.util.NameTag
@@ -50,14 +47,14 @@ internal class StateScopeImpl( 
    val nameData: NameData,

    val createdEpoch: Long,

    val evalScope: EvalScope,

    val aliveLazy: Lazy<State<Boolean>>,

    val deathSignalLazy: Lazy<Events<Any>>,

) : InternalStateScope, EvalScope by evalScope {



    init {

        nameData.forceInit()

    }



    override val alive: State<Boolean> by aliveLazy

    override val deathSignal: Events<Any> by deathSignalLazy



    override fun <A> deferredStateScope(block: StateScope.() -> A): DeferredValue<A> =

        DeferredValue(deferAsync { block() })
@@ -69,7 +66,7 @@ internal class StateScopeImpl( 
        val nameData = name.toNameData("Events.holdStateDeferred")

        // Ensure state is only collected until the end of this scope

        return truncateToScope(this@holdStateDeferred, nameData + "truncatedChanges")

            .holdStateInternalDeferred(nameData, this@StateScopeImpl, initialValue.unwrapped)

            .holdStateDeferredUnsafe(nameData, this@StateScopeImpl, initialValue.unwrapped)

    }



    override fun <K, V> Events<Map<K, Maybe<V>>>.foldStateMapIncrementally(
@@ -153,34 +150,17 @@ internal class StateScopeImpl( 
            nameData,

            epoch,

            evalScope,

            aliveLazy =

            deathSignalLazy =

                lazy {

                    alive

                        .changes(nameData + "parentAliveChanges")

                        .mapCheap { now }

                        .holdStateInternalDeferred(

                            nameData + "deathSignalInner",

                            this,

                            deferAsync {

                                if (alive.sample()) {

                                    childEndSignal.nextOnlyInternal(

                                        nameData + "firstEndSignal",

                                        this,

                                    )

                                } else {

                                    now

                                }

                            },

                        )

                        .switchEventsPromptly(nameData + "deathSignal")

                        .mapCheap(nameData + "mapFalse") { false }

                        .holdStateInternal(nameData + "isAlive", this, true)

                    mergeLeft(nameData + "mergedDeathSignal", deathSignal, childEndSignal)

                        .nextOnlyUnsafe(nameData + "firstEndSignal", this)

                },

        )



    override fun <A> truncateToScope(events: Events<A>, nameData: NameData): Events<A> =

        alive

            .mapCheapUnsafe(nameData + "mapCheapSwitchOff") { if (it) events else emptyEvents }

        deathSignal

            .mapCheap(nameData + "switchOff") { emptyEvents }

            .holdStateUnsafe(nameData + "switchedIn", this, events)

            .switchEvents(nameData)



    override fun toString(): String = "${super.toString()}[$nameData]"
@@ -191,33 +171,33 @@ private fun EvalScope.reenterStateScope(outerScope: StateScopeImpl) = 
        outerScope.nameData,

        outerScope.createdEpoch,

        evalScope = this,

        aliveLazy = outerScope.aliveLazy,

        deathSignalLazy = outerScope.deathSignalLazy,

    )



private fun <A> Events<A>.nextOnlyInternal(nameData: NameData, evalScope: EvalScope): Events<A> =

private fun <A> Events<A>.nextOnlyUnsafe(nameData: NameData, evalScope: EvalScope): Events<A> =

    if (this === emptyEvents) {

        this

    } else {

        EventsLoop<A>().apply {

            loopback =

                mapCheap(nameData + "shutoffEvent") { emptyEvents }

                    .holdStateInternal(nameData + "state", evalScope, this@nextOnlyInternal)

                    .holdStateUnsafe(nameData + "state", evalScope, this@nextOnlyUnsafe)

                    .switchEvents(nameData)

        }

    }



private fun <A> Events<A>.holdStateInternal(

private fun <A> Events<A>.holdStateUnsafe(

    nameData: NameData,

    evalScope: EvalScope,

    initialValue: A,

): State<A> = holdStateInternalDeferred(nameData, evalScope, lazyOf(initialValue))

): State<A> = holdStateDeferredUnsafe(nameData, evalScope, lazyOf(initialValue))



private fun <A> Events<A>.holdStateInternalDeferred(

private fun <A> Events<A>.holdStateDeferredUnsafe(

    nameData: NameData,

    evalScope: EvalScope,

    initialValue: Lazy<A>,

): State<A> {

    val changes = this@holdStateInternalDeferred

    val changes = this@holdStateDeferredUnsafe

    val impl =

        activatedStateSource(

            nameData,