Overhaul of Compose support.

I had originally thought about creating a new `ScreenComposableFactory : ViewRegistry.Entry`, but that did nothing but introduce complexity. The existing system has the elegant property that every `ViewFactory` can produce either a `@Composable` or a `View` as needed. That's a great invariant, and it's most easily maintained by teaching the same trick to `ScreenViewFactory`.

Where possible, existing tests are copied into new files with a `Legacy` prefix and otherwise unchanged, so that diffs of the original tests will be reviewable.

Author: rjrjr

gradle.properties

@@ -8,7 +8,7 @@ android.useAndroidX=true
 systemProp.org.gradle.internal.publish.checksums.insecure=true
 
 GROUP=com.squareup.workflow1
-VERSION_NAME=1.7.0-uiUpdate01-SNAPSHOT
+VERSION_NAME=1.7.0-uiUpdate02-SNAPSHOT
 
 POM_DESCRIPTION=Square Workflow
 

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocompose/App.kt

@@ -1,4 +1,5 @@
 @file:OptIn(WorkflowUiExperimentalApi::class)
+@file:Suppress("FunctionName")
 
 package com.squareup.sample.compose.hellocompose
 

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocompose/HelloBinding.kt

@@ -8,10 +8,10 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import com.squareup.sample.compose.hellocompose.HelloWorkflow.Rendering
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
-import com.squareup.workflow1.ui.compose.composeViewFactory
+import com.squareup.workflow1.ui.compose.composeScreenViewFactory
 
 @OptIn(WorkflowUiExperimentalApi::class)
-val HelloBinding = composeViewFactory<Rendering> { rendering, _ ->
+val HelloBinding = composeScreenViewFactory<Rendering> { rendering, _ ->
   Text(
     rendering.message,
     modifier = Modifier

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocompose/HelloWorkflow.kt

@@ -8,6 +8,8 @@ import com.squareup.workflow1.Snapshot
 import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.action
 import com.squareup.workflow1.parse
+import com.squareup.workflow1.ui.Screen
+import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 
 object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, Rendering>() {
   enum class State {
@@ -20,10 +22,11 @@ object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, Rendering>() {
     }
   }
 
+  @OptIn(WorkflowUiExperimentalApi::class)
   data class Rendering(
     val message: String,
     val onClick: () -> Unit
-  )
+  ) : Screen
 
   private val helloAction = action {
     state = state.theOtherState()

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposebinding/HelloBinding.kt

@@ -9,11 +9,11 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
 import com.squareup.sample.compose.hellocomposebinding.HelloWorkflow.Rendering
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
-import com.squareup.workflow1.ui.compose.composeViewFactory
+import com.squareup.workflow1.ui.compose.composeScreenViewFactory
 import com.squareup.workflow1.ui.compose.tooling.Preview
 
 @OptIn(WorkflowUiExperimentalApi::class)
-val HelloBinding = composeViewFactory<Rendering> { rendering, _ ->
+val HelloBinding = composeScreenViewFactory<Rendering> { rendering, _ ->
   Text(
     rendering.message,
     modifier = Modifier
@@ -23,6 +23,7 @@ val HelloBinding = composeViewFactory<Rendering> { rendering, _ ->
   )
 }
 
+@Suppress("FunctionName")
 @OptIn(WorkflowUiExperimentalApi::class)
 @Preview(heightDp = 150, showBackground = true)
 @Composable fun DrawHelloRenderingPreview() {

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposebinding/HelloWorkflow.kt

@@ -8,6 +8,8 @@ import com.squareup.workflow1.Snapshot
 import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.action
 import com.squareup.workflow1.parse
+import com.squareup.workflow1.ui.Screen
+import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 
 object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, Rendering>() {
   enum class State {
@@ -20,10 +22,11 @@ object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, Rendering>() {
     }
   }
 
+  @OptIn(WorkflowUiExperimentalApi::class)
   data class Rendering(
     val message: String,
     val onClick: () -> Unit
-  )
+  ) : Screen
 
   private val helloAction = action {
     state = state.theOtherState()

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposeworkflow/ComposeWorkflow.kt

@@ -1,3 +1,5 @@
+@file:Suppress("FunctionName")
+
 package com.squareup.sample.compose.hellocomposeworkflow
 
 import androidx.compose.runtime.Composable
@@ -7,11 +9,11 @@ import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.Workflow
 import com.squareup.workflow1.ui.ViewEnvironment
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
-import com.squareup.workflow1.ui.compose.ComposeRendering
+import com.squareup.workflow1.ui.compose.ComposeScreen
 
 /**
  * A stateless [Workflow] that [renders][RenderingContent] itself as a [Composable] function.
- * Effectively defines an inline [ComposeRendering].
+ * Effectively defines an inline [ComposeScreen].
  *
  * This workflow does not have access to a [RenderContext] since render contexts are only valid
  * during render passes, and this workflow's [RenderingContent] method is invoked after the render
@@ -28,8 +30,8 @@ import com.squareup.workflow1.ui.compose.ComposeRendering
  * comes up.
  */
 @WorkflowUiExperimentalApi
-public abstract class ComposeWorkflow<in PropsT, out OutputT : Any> :
-  Workflow<PropsT, OutputT, ComposeRendering> {
+abstract class ComposeWorkflow<in PropsT, out OutputT : Any> :
+  Workflow<PropsT, OutputT, ComposeScreen> {
 
   /**
    * Renders [props] by emitting Compose UI. This function will be called to update the UI whenever
@@ -40,21 +42,21 @@ public abstract class ComposeWorkflow<in PropsT, out OutputT : Any> :
    * workflow's parent.
    * @param viewEnvironment The [ViewEnvironment] passed down through the `ViewBinding` pipeline.
    */
-  @Composable public abstract fun RenderingContent(
+  @Composable abstract fun RenderingContent(
     props: PropsT,
     outputSink: Sink<OutputT>,
     viewEnvironment: ViewEnvironment
   )
 
-  override fun asStatefulWorkflow(): StatefulWorkflow<PropsT, *, OutputT, ComposeRendering> =
+  override fun asStatefulWorkflow(): StatefulWorkflow<PropsT, *, OutputT, ComposeScreen> =
     ComposeWorkflowImpl(this)
 }
 
 /**
  * Returns a [ComposeWorkflow] that renders itself using the given [render] function.
  */
 @WorkflowUiExperimentalApi
-public inline fun <PropsT, OutputT : Any> Workflow.Companion.composed(
+inline fun <PropsT, OutputT : Any> Workflow.Companion.composed(
   crossinline render: @Composable (
     props: PropsT,
     outputSink: Sink<OutputT>,

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposeworkflow/ComposeWorkflowImpl.kt

@@ -12,20 +12,20 @@ import com.squareup.workflow1.action
 import com.squareup.workflow1.contraMap
 import com.squareup.workflow1.ui.ViewEnvironment
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
-import com.squareup.workflow1.ui.compose.ComposeRendering
+import com.squareup.workflow1.ui.compose.ComposeScreen
 
 @WorkflowUiExperimentalApi
 internal class ComposeWorkflowImpl<PropsT, OutputT : Any>(
   private val workflow: ComposeWorkflow<PropsT, OutputT>
-) : StatefulWorkflow<PropsT, State<PropsT, OutputT>, OutputT, ComposeRendering>() {
+) : StatefulWorkflow<PropsT, State<PropsT, OutputT>, OutputT, ComposeScreen>() {
 
   // This doesn't need to be a @Model, it only gets set once, before the composable ever runs.
   class SinkHolder<OutputT>(var sink: Sink<OutputT>? = null)
 
   data class State<PropsT, OutputT>(
     val propsHolder: MutableState<PropsT>,
     val sinkHolder: SinkHolder<OutputT>,
-    val rendering: ComposeRendering
+    val rendering: ComposeScreen
   )
 
   override fun initialState(
@@ -38,7 +38,7 @@ internal class ComposeWorkflowImpl<PropsT, OutputT : Any>(
     return State(
       propsHolder,
       sinkHolder,
-      object : ComposeRendering {
+      object : ComposeScreen {
         @Composable override fun Content(viewEnvironment: ViewEnvironment) {
           // The sink will get set on the first render pass, which must happen before this is first
           // composed, so it should never be null.
@@ -63,7 +63,7 @@ internal class ComposeWorkflowImpl<PropsT, OutputT : Any>(
     renderProps: PropsT,
     renderState: State<PropsT, OutputT>,
     context: RenderContext
-  ): ComposeRendering {
+  ): ComposeScreen {
     // The first render pass needs to cache the sink. The sink is reusable, so we can just pass the
     // same one every time.
     if (renderState.sinkHolder.sink == null) {

samples/compose-samples/src/main/java/com/squareup/sample/compose/hellocomposeworkflow/HelloWorkflow.kt

@@ -8,14 +8,14 @@ import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.action
 import com.squareup.workflow1.parse
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
-import com.squareup.workflow1.ui.compose.ComposeRendering
+import com.squareup.workflow1.ui.compose.ComposeScreen
 
 /**
  * The root workflow of this sample. Manges the current toggle state and passes it to
  * [HelloComposeWorkflow].
  */
 @OptIn(WorkflowUiExperimentalApi::class)
-object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, ComposeRendering>() {
+object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, ComposeScreen>() {
   enum class State {
     Hello,
     Goodbye;
@@ -40,7 +40,7 @@ object HelloWorkflow : StatefulWorkflow<Unit, State, Nothing, ComposeRendering>(
     renderProps: Unit,
     renderState: State,
     context: RenderContext
-  ): ComposeRendering =
+  ): ComposeScreen =
     context.renderChild(HelloComposeWorkflow, renderState.name) { helloAction }
 
   override fun snapshotState(state: State): Snapshot = Snapshot.of(if (state == Hello) 1 else 0)

samples/compose-samples/src/main/java/com/squareup/sample/compose/inlinerendering/InlineRenderingWorkflow.kt

@@ -1,5 +1,5 @@
-@file:Suppress("DEPRECATION", "FunctionName")
 @file:OptIn(WorkflowUiExperimentalApi::class)
+@file:Suppress("FunctionName")
 
 package com.squareup.sample.compose.inlinerendering
 
@@ -20,14 +20,14 @@ import androidx.compose.ui.tooling.preview.Preview
 import com.squareup.workflow1.Snapshot
 import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.parse
-import com.squareup.workflow1.ui.AndroidViewRendering
+import com.squareup.workflow1.ui.AndroidScreen
 import com.squareup.workflow1.ui.ViewEnvironment
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
-import com.squareup.workflow1.ui.compose.ComposeRendering
+import com.squareup.workflow1.ui.compose.ComposeScreen
 import com.squareup.workflow1.ui.compose.WorkflowRendering
 import com.squareup.workflow1.ui.compose.renderAsState
 
-object InlineRenderingWorkflow : StatefulWorkflow<Unit, Int, Nothing, AndroidViewRendering<*>>() {
+object InlineRenderingWorkflow : StatefulWorkflow<Unit, Int, Nothing, AndroidScreen<*>>() {
 
   override fun initialState(
     props: Unit,
@@ -38,7 +38,7 @@ object InlineRenderingWorkflow : StatefulWorkflow<Unit, Int, Nothing, AndroidVie
     renderProps: Unit,
     renderState: Int,
     context: RenderContext
-  ): AndroidViewRendering<*> = ComposeRendering {
+  ): AndroidScreen<*> = ComposeScreen {
     Box {
       Button(onClick = context.eventHandler { state += 1 }) {
         Text("Counter: ")

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

@@ -8,18 +8,18 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
 import com.squareup.sample.compose.databinding.LegacyViewBinding
 import com.squareup.sample.compose.nestedrenderings.RecursiveWorkflow.LegacyRendering
-import com.squareup.workflow1.ui.LayoutRunner
-import com.squareup.workflow1.ui.LayoutRunner.Companion.bind
+import com.squareup.workflow1.ui.ScreenViewFactory
+import com.squareup.workflow1.ui.ScreenViewRunner
+import com.squareup.workflow1.ui.ScreenViewRunner.Companion.bind
 import com.squareup.workflow1.ui.ViewEnvironment
-import com.squareup.workflow1.ui.ViewFactory
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import com.squareup.workflow1.ui.compose.tooling.Preview
 
 /**
- * A [LayoutRunner] that renders [LegacyRendering]s using the legacy view framework.
+ * A [ScreenViewRunner] that renders [LegacyRendering]s using the legacy view framework.
  */
 @OptIn(WorkflowUiExperimentalApi::class)
-class LegacyRunner(private val binding: LegacyViewBinding) : LayoutRunner<LegacyRendering> {
+class LegacyRunner(private val binding: LegacyViewBinding) : ScreenViewRunner<LegacyRendering> {
 
   override fun showRendering(
     rendering: LegacyRendering,
@@ -28,16 +28,17 @@ class LegacyRunner(private val binding: LegacyViewBinding) : LayoutRunner<Legacy
     binding.stub.update(rendering.rendering, viewEnvironment)
   }
 
-  companion object : ViewFactory<LegacyRendering> by bind(
+  companion object : ScreenViewFactory<LegacyRendering> by bind(
     LegacyViewBinding::inflate, ::LegacyRunner
   )
 }
 
+@Suppress("FunctionName")
 @OptIn(WorkflowUiExperimentalApi::class)
 @Preview(widthDp = 200, heightDp = 150, showBackground = true)
 @Composable private fun LegacyRunnerPreview() {
   LegacyRunner.Preview(
-    rendering = LegacyRendering("child"),
+    rendering = LegacyRendering(StringRendering("child")),
     placeholderModifier = Modifier.fillMaxSize()
   )
 }

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

@@ -1,4 +1,4 @@
-@file:Suppress("RemoveEmptyParenthesesFromAnnotationEntry")
+@file:Suppress("RemoveEmptyParenthesesFromAnnotationEntry", "FunctionName")
 
 package com.squareup.sample.compose.nestedrenderings
 
@@ -23,10 +23,11 @@ import androidx.compose.ui.res.dimensionResource
 import androidx.compose.ui.tooling.preview.Preview
 import com.squareup.sample.compose.R
 import com.squareup.sample.compose.nestedrenderings.RecursiveWorkflow.Rendering
+import com.squareup.workflow1.ui.Screen
 import com.squareup.workflow1.ui.ViewEnvironment
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import com.squareup.workflow1.ui.compose.WorkflowRendering
-import com.squareup.workflow1.ui.compose.composeViewFactory
+import com.squareup.workflow1.ui.compose.composeScreenViewFactory
 import com.squareup.workflow1.ui.compose.tooling.Preview
 
 /**
@@ -38,7 +39,7 @@ val LocalBackgroundColor = compositionLocalOf<Color> { error("No background colo
  * A `ViewFactory` that renders [RecursiveWorkflow.Rendering]s.
  */
 @OptIn(WorkflowUiExperimentalApi::class)
-val RecursiveViewFactory = composeViewFactory<Rendering> { rendering, viewEnvironment ->
+val RecursiveViewFactory = composeScreenViewFactory<Rendering> { rendering, viewEnvironment ->
   // Every child should be drawn with a slightly-darker background color.
   val color = LocalBackgroundColor.current
   val childColor = remember(color) {
@@ -75,9 +76,9 @@ val RecursiveViewFactory = composeViewFactory<Rendering> { rendering, viewEnviro
     RecursiveViewFactory.Preview(
       Rendering(
         children = listOf(
-          "foo",
+          StringRendering("foo"),
           Rendering(
-            children = listOf("bar"),
+            children = listOf(StringRendering("bar")),
             onAddChildClicked = {}, onResetClicked = {}
           )
         ),
@@ -90,7 +91,7 @@ val RecursiveViewFactory = composeViewFactory<Rendering> { rendering, viewEnviro
 
 @OptIn(WorkflowUiExperimentalApi::class)
 @Composable private fun Children(
-  children: List<Any>,
+  children: List<Screen>,
   viewEnvironment: ViewEnvironment,
   modifier: Modifier
 ) {

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

@@ -7,6 +7,8 @@ import com.squareup.workflow1.Snapshot
 import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.action
 import com.squareup.workflow1.renderChild
+import com.squareup.workflow1.ui.Screen
+import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 
 /**
  * A simple workflow that produces [Rendering]s of zero or more children.
@@ -16,7 +18,8 @@ import com.squareup.workflow1.renderChild
  * 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, Any>() {
+@OptIn(WorkflowUiExperimentalApi::class)
+object RecursiveWorkflow : StatefulWorkflow<Unit, State, Nothing, Screen>() {
 
   data class State(val children: Int = 0)
 
@@ -28,15 +31,15 @@ object RecursiveWorkflow : StatefulWorkflow<Unit, State, Nothing, Any>() {
    * @param onResetClicked Resets [children] to an empty list.
    */
   data class Rendering(
-    val children: List<Any>,
+    val children: List<Screen>,
     val onAddChildClicked: () -> Unit,
     val onResetClicked: () -> Unit
-  )
+  ) : Screen
 
   /**
    * Wrapper around a [Rendering] that will be implemented using a legacy view.
    */
-  data class LegacyRendering(val rendering: Any)
+  data class LegacyRendering(val rendering: Screen) : Screen
 
   override fun initialState(
     props: Unit,

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

@@ -0,0 +1,7 @@
+package com.squareup.sample.compose.nestedrenderings
+
+import com.squareup.workflow1.ui.Screen
+import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
+
+@OptIn(WorkflowUiExperimentalApi::class)
+data class StringRendering(val value: String) : Screen