Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2dd8bf53 authored by Jordan Demeulenaere's avatar Jordan Demeulenaere
Browse files

Ensure that transitions are started only once 

This CL ensures that a single transition can not be started multiple
times.

This uncovered a bug introduced in ag/29024667: linked transitions would
run() their originalTransition rather than simply awaiting for them.
This later unveiled that we were using an incorrect coroutineScope {}
for linked transitions, as we would wait for all linked transitions to
finish before actually re-running the transition again in the original
STLState.

I didn't add more tests for linked transitions because I plan to remove
them in ag/30320655 anyways.

Bug: 376438969
Test: atest SceneTransitionLayoutStateTest
Flag: com.android.systemui.scene_container
Change-Id: Ie91771bea7e2d1db869b302305093283a2604943
parent a33c539a

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutState.kt

+5 −5
Original line number Diff line number Diff line
@@ -372,12 +372,12 @@ internal class MutableSceneTransitionLayoutStateImpl( 


            // Handle transition links.

            previousTransition?.let { cancelActiveTransitionLinks(it) }

            if (stateLinks.isNotEmpty()) {

                coroutineScope { setupTransitionLinks(transition) }

            }

            coroutineScope {

                setupTransitionLinks(transition)



                // Run the transition until it is finished.

            transition.run()

                transition.runInternal()

            }

        } finally {

            finishTransition(transition)

        }

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/content/state/TransitionState.kt

+22 −1
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ import com.android.compose.animation.scene.TransformationSpecImpl 
import com.android.compose.animation.scene.TransitionKey

import com.android.compose.animation.scene.transition.link.LinkedTransition

import com.android.compose.animation.scene.transition.link.StateLink

import kotlinx.coroutines.CompletableDeferred

import kotlinx.coroutines.launch



/** The state associated to a [SceneTransitionLayout] at some specific point in time. */
@@ -283,6 +284,12 @@ sealed interface TransitionState { 
        /** The map of active links that connects this transition to other transitions. */

        internal val activeTransitionLinks = mutableMapOf<StateLink, LinkedTransition>()



        /** Whether this transition was already started. */

        private var wasStarted = false



        /** A completable to [await] this transition. */

        private val completable = CompletableDeferred<Unit>()



        init {

            check(fromContent != toContent)

            check(
@@ -328,7 +335,7 @@ sealed interface TransitionState { 
        }



        /** Run this transition and return once it is finished. */

        abstract suspend fun run()

        protected abstract suspend fun run()



        /**

         * Freeze this transition state so that neither [currentScene] nor [currentOverlays] will
@@ -341,6 +348,20 @@ sealed interface TransitionState { 
         */

        abstract fun freezeAndAnimateToCurrentState()



        /** Wait for this transition to finish. */

        internal suspend fun await() = completable.await()



        internal suspend fun runInternal() {

            check(!wasStarted) { "A Transition can be started only once." }

            wasStarted = true



            try {

                run()

            } finally {

                completable.complete(Unit)

            }

        }



        internal fun updateOverscrollSpecs(

            fromSpec: OverscrollSpecImpl?,

            toSpec: OverscrollSpecImpl?,

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/transition/link/LinkedTransition.kt

+1 −1
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ internal class LinkedTransition( 
        get() = originalTransition.progressVelocity



    override suspend fun run() {

        originalTransition.run()

        originalTransition.await()

    }



    override fun freezeAndAnimateToCurrentState() {

packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/SceneTransitionLayoutStateTest.kt

+12 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ import kotlinx.coroutines.cancelAndJoin 
import kotlinx.coroutines.channels.Channel

import kotlinx.coroutines.flow.consumeAsFlow

import kotlinx.coroutines.launch

import kotlinx.coroutines.runBlocking

import kotlinx.coroutines.test.runTest

import org.junit.Assert.assertThrows

import org.junit.Rule
@@ -777,4 +778,15 @@ class SceneTransitionLayoutStateTest { 
        assertThat(transition.progressTo(SceneA)).isEqualTo(1f - 0.2f)

        assertThrows(IllegalArgumentException::class.java) { transition.progressTo(SceneC) }

    }



    @Test

    fun transitionCanBeStartedOnlyOnce() = runTest {

        val state = MutableSceneTransitionLayoutState(SceneA)

        val transition = transition(from = SceneA, to = SceneB)



        state.startTransitionImmediately(backgroundScope, transition)

        assertThrows(IllegalStateException::class.java) {

            runBlocking { state.startTransition(transition) }

        }

    }

}