Renames ComposeViewFactoryRoot to CompositionRoot and decouples the implementation.

The root is now applied via a `ViewRegistry` wrapper that wraps individual factories
to apply the root, instead of having this logic hard-coded inside `ComposeViewFactory`.

This approach is more flexible in general (could be used to do other tricks), and decouples
the rooting feature from the rest of the code.

Author: zach-klippenstein

core-compose/api/core-compose.api

@@ -15,24 +15,6 @@ public final class com/squareup/workflow/ui/compose/ComposeViewFactory : com/squ
 	public fun getType ()Lkotlin/reflect/KClass;
 }
 
-public abstract interface class com/squareup/workflow/ui/compose/ComposeViewFactoryRoot {
-	public static final field Companion Lcom/squareup/workflow/ui/compose/ComposeViewFactoryRoot$Companion;
-	public static fun <clinit> ()V
-	public abstract fun wrap (Lkotlin/jvm/functions/Function1;Landroidx/compose/Composer;)V
-}
-
-public final class com/squareup/workflow/ui/compose/ComposeViewFactoryRoot$Companion : com/squareup/workflow/ui/ViewEnvironmentKey {
-	public static final fun <clinit> ()V
-	public fun getDefault ()Lcom/squareup/workflow/ui/compose/ComposeViewFactoryRoot;
-	public synthetic fun getDefault ()Ljava/lang/Object;
-}
-
-public final class com/squareup/workflow/ui/compose/ComposeViewFactoryRootKt {
-	public static final fun <clinit> ()V
-	public static final fun ComposeViewFactoryRoot (Lkotlin/jvm/functions/Function2;)Lcom/squareup/workflow/ui/compose/ComposeViewFactoryRoot;
-	public static final fun withComposeViewFactoryRoot (Lcom/squareup/workflow/ui/ViewEnvironment;Lkotlin/jvm/functions/Function2;)Lcom/squareup/workflow/ui/ViewEnvironment;
-}
-
 public abstract class com/squareup/workflow/ui/compose/ComposeWorkflow : com/squareup/workflow/Workflow {
 	public fun <init> ()V
 	public fun asStatefulWorkflow ()Lcom/squareup/workflow/StatefulWorkflow;
@@ -43,6 +25,12 @@ public final class com/squareup/workflow/ui/compose/ComposeWorkflowKt {
 	public static final fun composed (Lcom/squareup/workflow/Workflow$Companion;Lkotlin/jvm/functions/Function4;)Lcom/squareup/workflow/ui/compose/ComposeWorkflow;
 }
 
+public final class com/squareup/workflow/ui/compose/CompositionRootKt {
+	public static final fun <clinit> ()V
+	public static final fun withCompositionRoot (Lcom/squareup/workflow/ui/ViewEnvironment;Lkotlin/jvm/functions/Function2;)Lcom/squareup/workflow/ui/ViewEnvironment;
+	public static final fun withCompositionRoot (Lcom/squareup/workflow/ui/ViewRegistry;Lkotlin/jvm/functions/Function2;)Lcom/squareup/workflow/ui/ViewRegistry;
+}
+
 public final class com/squareup/workflow/ui/compose/ViewEnvironmentsKt {
 	public static final fun WorkflowRendering (Ljava/lang/Object;Lcom/squareup/workflow/ui/ViewEnvironment;Landroidx/ui/core/Modifier;Landroidx/compose/Composer;)V
 	public static synthetic fun WorkflowRendering$default (Ljava/lang/Object;Lcom/squareup/workflow/ui/ViewEnvironment;Landroidx/ui/core/Modifier;Landroidx/compose/Composer;ILjava/lang/Object;)V

core-compose/src/androidTest/java/com/squareup/workflow/ui/compose/ComposeViewFactoryTest.kt

@@ -40,7 +40,7 @@ class ComposeViewFactoryTest {
   @Test fun wrapsFactoryWithRoot() {
     val wrapperText = mutableStateOf("one")
     val viewEnvironment = ViewEnvironment(ViewRegistry(TestFactory))
-        .withComposeViewFactoryRoot { content ->
+        .withCompositionRoot { content ->
           Column {
             Text(wrapperText.value)
             content()

core-compose/src/androidTest/java/com/squareup/workflow/ui/compose/internal/SafeComposeViewFactoryRootTest.kt renamed to core-compose/src/androidTest/java/com/squareup/workflow/ui/compose/CompositionRootTest.kt

@@ -13,8 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.squareup.workflow.ui.compose.internal
+package com.squareup.workflow.ui.compose
 
+import androidx.compose.FrameManager
+import androidx.compose.mutableStateOf
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.ui.foundation.Text
 import androidx.ui.layout.Column
@@ -23,28 +25,114 @@ import androidx.ui.test.assertIsDisplayed
 import androidx.ui.test.createComposeRule
 import androidx.ui.test.findByText
 import com.google.common.truth.Truth.assertThat
-import com.squareup.workflow.ui.compose.ComposeViewFactoryRoot
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import kotlin.test.assertFailsWith
 
 @RunWith(AndroidJUnit4::class)
-class SafeComposeViewFactoryRootTest {
+class CompositionRootTest {
 
   @Rule @JvmField val composeRule = createComposeRule()
 
+  @Test fun wrapWithRootIfNecessary_wrapsWhenNecessary() {
+    val root: CompositionRoot = { content ->
+      Column {
+        Text("one")
+        content()
+      }
+    }
+
+    composeRule.setContent {
+      wrapWithRootIfNecessary(root) {
+        Text("two")
+      }
+    }
+
+    findByText("one\ntwo").assertIsDisplayed()
+  }
+
+  @Test fun wrapWithRootIfNecessary_onlyWrapsOnce() {
+    val root: CompositionRoot = { content ->
+      Column {
+        Text("one")
+        content()
+      }
+    }
+
+    composeRule.setContent {
+      wrapWithRootIfNecessary(root) {
+        Text("two")
+        wrapWithRootIfNecessary(root) {
+          Text("three")
+        }
+      }
+    }
+
+    findByText("one\ntwo\nthree").assertIsDisplayed()
+  }
+
+  @Test fun wrapWithRootIfNecessary_seesUpdatesFromRootWrapper() {
+    val wrapperText = mutableStateOf("one")
+    val root: CompositionRoot = { content ->
+      Column {
+        Text(wrapperText.value)
+        content()
+      }
+    }
+
+    composeRule.setContent {
+      wrapWithRootIfNecessary(root) {
+        Text("two")
+      }
+    }
+
+    findByText("one\ntwo").assertIsDisplayed()
+    FrameManager.framed {
+      wrapperText.value = "ENO"
+    }
+    findByText("ENO\ntwo").assertIsDisplayed()
+  }
+
+  @Test fun wrapWithRootIfNecessary_rewrapsWhenDifferentRoot() {
+    val root1: CompositionRoot = { content ->
+      Column {
+        Text("one")
+        content()
+      }
+    }
+    val root2: CompositionRoot = { content ->
+      Column {
+        Text("ENO")
+        content()
+      }
+    }
+    val viewEnvironment = mutableStateOf(root1)
+
+    composeRule.setContent {
+      wrapWithRootIfNecessary(viewEnvironment.value) {
+        Text("two")
+      }
+    }
+
+    findByText("one\ntwo").assertIsDisplayed()
+    FrameManager.framed {
+      viewEnvironment.value = root2
+    }
+    findByText("ENO\ntwo").assertIsDisplayed()
+  }
+
   @Test fun safeComposeViewFactoryRoot_wraps_content() {
-    val wrapped = ComposeViewFactoryRoot { content ->
+    val wrapped: CompositionRoot = { content ->
       Column {
         Text("Parent")
         content()
       }
     }
-    val safeRoot = SafeComposeViewFactoryRoot(wrapped)
+    val safeRoot = safeCompositionRoot(wrapped)
 
     composeRule.setContent {
-      safeRoot.wrap {
+      safeRoot {
         // Need an explicit semantics container, otherwise both Texts will be merged into a single
         // Semantics object with the text "Parent\nChild".
         Semantics(container = true) {
@@ -58,12 +146,12 @@ class SafeComposeViewFactoryRootTest {
   }
 
   @Test fun safeComposeViewFactoryRoot_throws_whenChildrenNotInvoked() {
-    val wrapped = ComposeViewFactoryRoot { }
-    val safeRoot = SafeComposeViewFactoryRoot(wrapped)
+    val wrapped: CompositionRoot = { }
+    val safeRoot = safeCompositionRoot(wrapped)
 
     val error = assertFailsWith<IllegalStateException> {
       composeRule.setContent {
-        safeRoot.wrap {}
+        safeRoot {}
       }
     }
 
@@ -74,15 +162,15 @@ class SafeComposeViewFactoryRootTest {
   }
 
   @Test fun safeComposeViewFactoryRoot_throws_whenChildrenInvokedMultipleTimes() {
-    val wrapped = ComposeViewFactoryRoot { children ->
+    val wrapped: CompositionRoot = { children ->
       children()
       children()
     }
-    val safeRoot = SafeComposeViewFactoryRoot(wrapped)
+    val safeRoot = safeCompositionRoot(wrapped)
 
     val error = assertFailsWith<IllegalStateException> {
       composeRule.setContent {
-        safeRoot.wrap {
+        safeRoot {
           Text("Hello")
         }
       }

core-compose/src/androidTest/java/com/squareup/workflow/ui/compose/internal/ComposeViewFactoryRootTest.kt

@@ -25,7 +25,7 @@ import com.squareup.workflow.ui.ViewEnvironment
 import com.squareup.workflow.ui.ViewRegistry
 import com.squareup.workflow.ui.compose.composedViewFactory
 import com.squareup.workflow.ui.compose.WorkflowRendering
-import com.squareup.workflow.ui.compose.withComposeViewFactoryRoot
+import com.squareup.workflow.ui.compose.withCompositionRoot
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -37,7 +37,7 @@ class ViewFactoriesTest {
 
   @Test fun WorkflowRendering_wrapsFactoryWithRoot_whenAlreadyInComposition() {
     val viewEnvironment = ViewEnvironment(ViewRegistry(TestFactory))
-        .withComposeViewFactoryRoot { content ->
+        .withCompositionRoot { content ->
           Column {
             Text("one")
             content()