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Commit d57efdf2 authored by Chris Göllner's avatar Chris Göllner
Browse files

DisplayRepository: tweak to implementation of displayAdditionEvent 

- Change it so that it only emits after `displays` has emitted. This
  guarantees that calls to `getDisplay` with the newly added display id
  will always be non-null.
- This also allows us to reuse an existing `Display` instance, without
  having to do another call to `DisplayManager`

Test: DisplayRepositoryTest
Bug: 367592591
Flag: EXEMPT small implementation tweak covered with tests
Change-Id: Ic5d6f877d8ab77f13e239632f6dee1deecdf97eb
parent 92be35f8

packages/SystemUI/multivalentTests/src/com/android/systemui/display/data/repository/DisplayRepositoryTest.kt

+22 −0
Original line number Diff line number Diff line
@@ -439,6 +439,28 @@ class DisplayRepositoryTest : SysuiTestCase() { 
            assertThat(display!!.type).isEqualTo(TYPE_EXTERNAL)

        }



    @Test

    fun displayAdditionEvent_emptyByDefault() =

        testScope.runTest {

            setDisplays(1, 2, 3)



            val lastAddedDisplay by lastDisplayAdditionEvent()



            assertThat(lastAddedDisplay).isNull()

        }



    @Test

    fun displayAdditionEvent_displaysAdded_doesNotReplayEventsToNewSubscribers() =

        testScope.runTest {

            val priorDisplayAdded by lastDisplayAdditionEvent()

            setDisplays(1)

            sendOnDisplayAdded(1)

            assertThat(priorDisplayAdded?.displayId).isEqualTo(1)



            val lastAddedDisplay by collectLastValue(displayRepository.displayAdditionEvent)

            assertThat(lastAddedDisplay).isNull()

        }



    @Test

    fun defaultDisplayOff_changes() =

        testScope.runTest {

packages/SystemUI/src/com/android/systemui/display/data/repository/DisplayRepository.kt

+14 −6
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ import com.android.systemui.dagger.SysUISingleton 
import com.android.systemui.dagger.qualifiers.Background

import com.android.systemui.display.data.DisplayEvent

import com.android.systemui.util.Compile

import com.android.systemui.util.kotlin.pairwiseBy

import javax.inject.Inject

import kotlinx.coroutines.CoroutineDispatcher

import kotlinx.coroutines.CoroutineScope
@@ -41,11 +42,12 @@ import kotlinx.coroutines.flow.Flow 
import kotlinx.coroutines.flow.MutableStateFlow

import kotlinx.coroutines.flow.SharingStarted

import kotlinx.coroutines.flow.StateFlow

import kotlinx.coroutines.flow.asFlow

import kotlinx.coroutines.flow.combine

import kotlinx.coroutines.flow.distinctUntilChanged

import kotlinx.coroutines.flow.filter

import kotlinx.coroutines.flow.filterIsInstance

import kotlinx.coroutines.flow.first

import kotlinx.coroutines.flow.flatMapLatest

import kotlinx.coroutines.flow.flowOn

import kotlinx.coroutines.flow.map

import kotlinx.coroutines.flow.onEach
@@ -146,11 +148,6 @@ constructor( 
    override val displayChangeEvent: Flow<Int> =

        allDisplayEvents.filterIsInstance<DisplayEvent.Changed>().map { event -> event.displayId }



    override val displayAdditionEvent: Flow<Display?> =

        allDisplayEvents.filterIsInstance<DisplayEvent.Added>().map {

            getDisplayFromDisplayManager(it.displayId)

        }



    override val displayRemovalEvent: Flow<Int> =

        allDisplayEvents.filterIsInstance<DisplayEvent.Removed>().map { it.displayId }
@@ -212,6 +209,17 @@ constructor( 
     */

    override val displays: StateFlow<Set<Display>> = enabledDisplays



    /**

     * Implementation that maps from [displays], instead of [allDisplayEvents] for 2 reasons:

     * 1. Guarantee that it emits __after__ [displays] emitted. This way it is guaranteed that

     *    calling [getDisplay] for the newly added display will be non-null.

     * 2. Reuse the existing instance of [Display] without a new call to [DisplayManager].

     */

    override val displayAdditionEvent: Flow<Display?> =

        displays

            .pairwiseBy { previousDisplays, currentDisplays -> currentDisplays - previousDisplays }

            .flatMapLatest { it.asFlow() }



    val _ignoredDisplayIds = MutableStateFlow<Set<Int>>(emptySet())

    private val ignoredDisplayIds: Flow<Set<Int>> = _ignoredDisplayIds.debugLog("ignoredDisplayIds")