Introduce ComposeWorkflow.

benchmarks/performance-poetry/complex-poetry/src/main/java/com/squareup/benchmarks/performance/complex/poetry/instrumentation/PerformanceTracingInterceptor.kt

@@ -1,9 +1,12 @@
 package com.squareup.benchmarks.performance.complex.poetry.instrumentation
 
+import androidx.compose.runtime.Composable
 import androidx.tracing.Trace
 import com.squareup.benchmarks.performance.complex.poetry.PerformancePoemWorkflow
 import com.squareup.benchmarks.performance.complex.poetry.PerformancePoemsBrowserWorkflow
+import com.squareup.benchmarks.performance.complex.poetry.instrumentation.PerformanceTracingInterceptor.Companion.NODES_TO_TRACE
 import com.squareup.workflow1.BaseRenderContext
+import com.squareup.workflow1.WorkflowExperimentalApi
 import com.squareup.workflow1.WorkflowInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.RenderContextInterceptor
 import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
@@ -27,6 +30,24 @@ class PerformanceTracingInterceptor(
     context: BaseRenderContext<P, S, O>,
     proceed: (P, S, RenderContextInterceptor<P, S, O>?) -> R,
     session: WorkflowSession
+  ): R = traceRender(session) {
+    proceed(renderProps, renderState, null)
+  }
+
+  @OptIn(WorkflowExperimentalApi::class)
+  @Composable
+  override fun <P, O, R> onRenderComposeWorkflow(
+    renderProps: P,
+    emitOutput: (O) -> Unit,
+    proceed: @Composable (P, (O) -> Unit) -> R,
+    session: WorkflowSession
+  ): R = traceRender(session) {
+    proceed(renderProps, emitOutput)
+  }
+
+  private inline fun <R> traceRender(
+    session: WorkflowSession,
+    render: () -> R
   ): R {
     val isRoot = session.parent == null
     val traceIdIndex = NODES_TO_TRACE.indexOfFirst { it.second == session.identifier }
@@ -45,7 +66,7 @@ class PerformanceTracingInterceptor(
       Trace.beginSection(sectionName)
     }
 
-    return proceed(renderProps, renderState, null).also {
+    return render().also {
       if (traceIdIndex > -1 && !sample) {
         Trace.endSection()
       }

samples/compose-samples/src/main/java/com/squareup/sample/compose/nestedrenderings/NestedRenderingsActivity.kt

@@ -10,6 +10,7 @@ import androidx.compose.ui.graphics.Color
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.squareup.workflow1.SimpleLoggingWorkflowInterceptor
 import com.squareup.workflow1.WorkflowExperimentalRuntime
 import com.squareup.workflow1.config.AndroidRuntimeConfigTools
 import com.squareup.workflow1.mapRendering
@@ -47,7 +48,8 @@ class NestedRenderingsActivity : AppCompatActivity() {
         workflow = RecursiveWorkflow.mapRendering { it.withEnvironment(viewEnvironment) },
         scope = viewModelScope,
         savedStateHandle = savedState,
-        runtimeConfig = AndroidRuntimeConfigTools.getAppWorkflowRuntimeConfig()
+        runtimeConfig = AndroidRuntimeConfigTools.getAppWorkflowRuntimeConfig(),
+        interceptors = listOf(SimpleLoggingWorkflowInterceptor())
       )
     }
   }

samples/compose-samples/src/main/java/com/squareup/sample/compose/nestedrenderings/RecursiveViewFactory.kt

@@ -2,6 +2,14 @@
 
 package com.squareup.sample.compose.nestedrenderings
 
+import androidx.compose.animation.Animatable
+import androidx.compose.animation.core.FastOutLinearInEasing
+import androidx.compose.animation.core.LinearOutSlowInEasing
+import androidx.compose.animation.core.keyframes
+import androidx.compose.foundation.gestures.awaitEachGesture
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.PressInteraction
 import androidx.compose.foundation.layout.Arrangement.SpaceEvenly
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
@@ -13,12 +21,17 @@ import androidx.compose.material.Card
 import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment.Companion.CenterHorizontally
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.compositeOver
+import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.res.dimensionResource
 import androidx.compose.ui.tooling.preview.Preview
 import com.squareup.sample.compose.R
@@ -27,6 +40,7 @@ import com.squareup.workflow1.ui.Screen
 import com.squareup.workflow1.ui.compose.ScreenComposableFactory
 import com.squareup.workflow1.ui.compose.WorkflowRendering
 import com.squareup.workflow1.ui.compose.tooling.Preview
+import kotlin.time.DurationUnit.MILLISECONDS
 
 /**
  * Composition local of [Color] to use as the background color for a [RecursiveComposableFactory].
@@ -44,7 +58,26 @@ val RecursiveComposableFactory = ScreenComposableFactory<Rendering> { rendering
       .compositeOver(Color.Black)
   }
 
-  Card(backgroundColor = color) {
+  var lastFlashedTrigger by remember { mutableIntStateOf(rendering.flashTrigger) }
+  val flashAlpha = remember { Animatable(Color(0x00FFFFFF)) }
+
+  // Flash the card white when asked.
+  LaunchedEffect(rendering.flashTrigger) {
+    if (rendering.flashTrigger != 0) {
+      lastFlashedTrigger = rendering.flashTrigger
+      flashAlpha.animateTo(Color(0x00FFFFFF), animationSpec = keyframes {
+        Color.White at (rendering.flashTime / 7).toInt(MILLISECONDS) using FastOutLinearInEasing
+        Color(0x00FFFFFF) at rendering.flashTime.toInt(MILLISECONDS) using LinearOutSlowInEasing
+      })
+    }
+  }
+
+  Card(
+    backgroundColor = flashAlpha.value.compositeOver(color),
+    modifier = Modifier.pointerInput(rendering) {
+      detectTapGestures(onPress = { rendering.onSelfClicked() })
+    }
+  ) {
     Column(
       Modifier
         .padding(dimensionResource(R.dimen.recursive_padding))
@@ -76,10 +109,14 @@ fun RecursiveViewFactoryPreview() {
           StringRendering("foo"),
           Rendering(
             children = listOf(StringRendering("bar")),
+            flashTrigger = 0,
+            onSelfClicked = {},
             onAddChildClicked = {},
             onResetClicked = {}
           )
         ),
+        flashTrigger = 0,
+        onSelfClicked = {},
         onAddChildClicked = {},
         onResetClicked = {}
       ),

samples/compose-samples/src/main/java/com/squareup/sample/compose/nestedrenderings/RecursiveWorkflow.kt

@@ -1,16 +1,30 @@
 package com.squareup.sample.compose.nestedrenderings
 
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
 import com.squareup.sample.compose.databinding.LegacyViewBinding
 import com.squareup.sample.compose.nestedrenderings.RecursiveWorkflow.LegacyRendering
 import com.squareup.sample.compose.nestedrenderings.RecursiveWorkflow.Rendering
-import com.squareup.sample.compose.nestedrenderings.RecursiveWorkflow.State
-import com.squareup.workflow1.Snapshot
-import com.squareup.workflow1.StatefulWorkflow
-import com.squareup.workflow1.action
-import com.squareup.workflow1.renderChild
+import com.squareup.workflow1.WorkflowExperimentalApi
+import com.squareup.workflow1.compose.ComposeWorkflow
+import com.squareup.workflow1.compose.renderChild
 import com.squareup.workflow1.ui.AndroidScreen
 import com.squareup.workflow1.ui.Screen
 import com.squareup.workflow1.ui.ScreenViewFactory
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.ZERO
+import kotlin.time.Duration.Companion.seconds
 
 /**
  * A simple workflow that produces [Rendering]s of zero or more children.
@@ -20,9 +34,8 @@ import com.squareup.workflow1.ui.ScreenViewFactory
  * to force it to go through the legacy view layer. This way this sample both demonstrates pass-
  * through Composable renderings as well as adapting in both directions.
  */
-object RecursiveWorkflow : StatefulWorkflow<Unit, State, Nothing, Screen>() {
-
-  data class State(val children: Int = 0)
+@OptIn(WorkflowExperimentalApi::class)
+object RecursiveWorkflow : ComposeWorkflow<Unit, Unit, Screen>() {
 
   /**
    * A rendering from a [RecursiveWorkflow].
@@ -33,8 +46,11 @@ object RecursiveWorkflow : StatefulWorkflow<Unit, State, Nothing, Screen>() {
    */
   data class Rendering(
     val children: List<Screen>,
-    val onAddChildClicked: () -> Unit,
-    val onResetClicked: () -> Unit
+    val flashTrigger: Int = 0,
+    val flashTime: Duration = ZERO,
+    val onSelfClicked: () -> Unit = {},
+    val onAddChildClicked: () -> Unit = {},
+    val onResetClicked: () -> Unit = {}
   ) : Screen
 
   /**
@@ -49,33 +65,45 @@ object RecursiveWorkflow : StatefulWorkflow<Unit, State, Nothing, Screen>() {
     )
   }
 
-  override fun initialState(
+  @OptIn(ExperimentalStdlibApi::class)
+  @Composable override fun produceRendering(
     props: Unit,
-    snapshot: Snapshot?
-  ): State = State()
+    emitOutput: (Unit) -> Unit
+  ): Screen {
+    var children by rememberSaveable { mutableStateOf(0) }
+    var flashTrigger by remember { mutableIntStateOf(0) }
+    val coroutineScope = rememberCoroutineScope()
+
+    DisposableEffect(Unit) {
+      println("OMG coroutineScope dispatcher: ${coroutineScope.coroutineContext[CoroutineDispatcher]}")
+      onDispose {}
+    }
+
+    LaunchedEffect(Unit) {
+      println("OMG LaunchedEffect dispatcher: ${coroutineScope.coroutineContext[CoroutineDispatcher]}")
+    }
 
-  override fun render(
-    renderProps: Unit,
-    renderState: State,
-    context: RenderContext<Unit, State, Nothing>
-  ): Rendering {
     return Rendering(
-      children = List(renderState.children) { i ->
-        val child = context.renderChild(RecursiveWorkflow, key = i.toString())
+      children = List(children) { i ->
+        val child = renderChild(RecursiveWorkflow, onOutput = {
+          // When a child is clicked, cascade the flash up.
+          coroutineScope.launch {
+            delay(0.1.seconds)
+            flashTrigger++
+            emitOutput(Unit)
+          }
+        })
         if (i % 2 == 0) child else LegacyRendering(child)
       },
-      onAddChildClicked = { context.actionSink.send(addChild()) },
-      onResetClicked = { context.actionSink.send(reset()) }
+      flashTrigger = flashTrigger,
+      flashTime = 0.5.seconds,
+      // Trigger a cascade of flashes when clicked.
+      onSelfClicked = {
+        flashTrigger++
+        emitOutput(Unit)
+      },
+      onAddChildClicked = { children++ },
+      onResetClicked = { children = 0 }
     )
   }
-
-  override fun snapshotState(state: State): Snapshot? = null
-
-  private fun addChild() = action("addChild") {
-    state = state.copy(children = state.children + 1)
-  }
-
-  private fun reset() = action("reset") {
-    state = State()
-  }
 }

samples/hello-compose-workflow/build.gradle.kts

@@ -0,0 +1,26 @@
+plugins {
+  id("com.android.application")
+  id("kotlin-android")
+  id("android-sample-app")
+  id("android-ui-tests")
+  alias(libs.plugins.compose.compiler)
+}
+
+android {
+  defaultConfig {
+    applicationId = "com.squareup.sample.hellocomposeworkflow"
+  }
+  namespace = "com.squareup.sample.hellocomposeworkflow"
+}
+
+dependencies {
+  debugImplementation(libs.squareup.leakcanary.android)
+
+  implementation(libs.androidx.activity.ktx)
+  implementation(libs.androidx.lifecycle.viewmodel.ktx)
+  implementation(libs.androidx.lifecycle.viewmodel.savedstate)
+  implementation(libs.androidx.viewbinding)
+
+  implementation(project(":workflow-ui:core-android"))
+  implementation(project(":workflow-ui:core-common"))
+}

samples/hello-compose-workflow/lint-baseline.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<issues format="6" by="lint 7.4.1" type="baseline" client="gradle" dependencies="false" name="AGP (7.4.1)" variant="all" version="7.4.1">
+
+    <issue
+        id="DataExtractionRules"
+        message="The attribute `android:allowBackup` is deprecated from Android 12 and higher and may be removed in future versions. Consider adding the attribute `android:dataExtractionRules` specifying an `@xml` resource which configures cloud backups and device transfers on Android 12 and higher."
+        errorLine1="      android:allowBackup=&quot;false&quot;"
+        errorLine2="                           ~~~~~">
+        <location
+            file="src/main/AndroidManifest.xml"
+            line="6"
+            column="28"/>
+    </issue>
+
+</issues>

samples/hello-compose-workflow/src/androidTest/java/com/squareup/sample/hellocomposeworkflow/HelloComposeWorkflowAppTest.kt

@@ -0,0 +1,38 @@
+package com.squareup.sample.hellocomposeworkflow
+
+import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.action.ViewActions.click
+import androidx.test.espresso.assertion.ViewAssertions.matches
+import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
+import androidx.test.espresso.matcher.ViewMatchers.withText
+import androidx.test.ext.junit.rules.ActivityScenarioRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.squareup.workflow1.ui.internal.test.IdlingDispatcherRule
+import leakcanary.DetectLeaksAfterTestSuccess
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.RuleChain
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class HelloComposeWorkflowAppTest {
+
+  private val scenarioRule = ActivityScenarioRule(HelloComposeWorkflowActivity::class.java)
+
+  @get:Rule val rules: RuleChain = RuleChain.outerRule(DetectLeaksAfterTestSuccess())
+    .around(scenarioRule)
+    .around(IdlingDispatcherRule)
+
+  @Test fun togglesHelloAndGoodbye() {
+    onView(withText("Hello"))
+      .check(matches(isDisplayed()))
+      .perform(click())
+
+    onView(withText("Goodbye"))
+      .check(matches(isDisplayed()))
+      .perform(click())
+
+    onView(withText("Hello"))
+      .check(matches(isDisplayed()))
+  }
+}

samples/hello-compose-workflow/src/main/AndroidManifest.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+  <application
+      android:allowBackup="false"
+      android:label="@string/app_name"
+      android:theme="@style/AppTheme"
+      tools:ignore="GoogleAppIndexingWarning,MissingApplicationIcon"
+      >
+
+    <activity android:name="com.squareup.sample.hellocomposeworkflow.HelloComposeWorkflowActivity"
+        android:exported="true">
+
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN" />
+        <category android:name="android.intent.category.LAUNCHER" />
+      </intent-filter>
+
+    </activity>
+
+  </application>
+</manifest>