Move SnapshotParcels.kt to workflow-core.

This gives workflow-core an android source set and moves the Parcelable-related
Snapshot helpers to it. This makes more sense since the other Snapshot helpers
are in the core module, and Parcelable isn't a UI thing it's just an android thing.

This also paves the way for go/compose-based-workflow to use these helpers to
support `rememberSaveable`.

Author: zach-klippenstein

samples/containers/hello-back-button/src/main/java/com/squareup/sample/hellobackbutton/AreYouSureWorkflow.kt

@@ -10,6 +10,8 @@ import com.squareup.workflow1.Snapshot
 import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.WorkflowAction.Companion.noAction
 import com.squareup.workflow1.action
+import com.squareup.workflow1.toParcelable
+import com.squareup.workflow1.toSnapshot
 import com.squareup.workflow1.ui.AndroidScreen
 import com.squareup.workflow1.ui.Screen
 import com.squareup.workflow1.ui.ScreenViewFactory
@@ -22,8 +24,6 @@ import com.squareup.workflow1.ui.navigation.AlertOverlay.Event.ButtonClicked
 import com.squareup.workflow1.ui.navigation.AlertOverlay.Event.Canceled
 import com.squareup.workflow1.ui.navigation.BackButtonScreen
 import com.squareup.workflow1.ui.navigation.BodyAndOverlaysScreen
-import com.squareup.workflow1.ui.toParcelable
-import com.squareup.workflow1.ui.toSnapshot
 import kotlinx.parcelize.Parcelize
 
 /**

samples/containers/hello-back-button/src/main/java/com/squareup/sample/hellobackbutton/HelloBackButtonWorkflow.kt

@@ -7,8 +7,8 @@ import com.squareup.sample.hellobackbutton.HelloBackButtonWorkflow.State.Baker
 import com.squareup.sample.hellobackbutton.HelloBackButtonWorkflow.State.Charlie
 import com.squareup.workflow1.Snapshot
 import com.squareup.workflow1.StatefulWorkflow
-import com.squareup.workflow1.ui.toParcelable
-import com.squareup.workflow1.ui.toSnapshot
+import com.squareup.workflow1.toParcelable
+import com.squareup.workflow1.toSnapshot
 import kotlinx.parcelize.Parcelize
 
 object HelloBackButtonWorkflow : StatefulWorkflow<Unit, State, Nothing, HelloBackButtonScreen>() {

workflow-core/api/workflow-core.api renamed to workflow-core/api/jvm/workflow-core.api

@@ -386,7 +386,7 @@ public final class com/squareup/workflow1/WorkflowIdentifier$Companion {
 	public final fun parse (Lokio/ByteString;)Lcom/squareup/workflow1/WorkflowIdentifier;
 }
 
-public final class com/squareup/workflow1/WorkflowIdentifierExKt {
+public final class com/squareup/workflow1/WorkflowIdentifierEx_jvmKt {
 	public static final fun getWorkflowIdentifier (Lkotlin/reflect/KClass;)Lcom/squareup/workflow1/WorkflowIdentifier;
 }
 

workflow-core/build.gradle.kts

@@ -2,6 +2,7 @@ import com.squareup.workflow1.buildsrc.iosWithSimulatorArm64
 
 plugins {
   id("kotlin-multiplatform")
+  id("com.android.kotlin.multiplatform.library")
   id("published")
 }
 
@@ -13,18 +14,63 @@ kotlin {
   if (targets == "kmp" || targets == "jvm") {
     jvm { withJava() }
   }
+  // The default KMP
+  // ["hierarchy template"](https://www.jetbrains.com/help/kotlin-multiplatform-dev/multiplatform-hierarchy.html#see-the-full-hierarchy-template)
+  // configures `androidMain` and `jvmMain` to be entirely separate targets, even though Android
+  // *can* be made to be a child of JVM. Changing this requires completely wiring up all targets
+  // ourselves though, so for now we've left them separate to simplify gradle config. If there ends
+  // up being too much code duplication, we can either make `androidMain` a child of `jvmMain`, or
+  // introduce a new shared target that includes both of them. Compose, for example, uses a
+  // structure where `jvm` is the shared parent of both `android` and `desktop`.
+  if (targets == "kmp" || targets == "android") {
+    androidLibrary {
+      namespace = "com.squareup.workflow1.android"
+      testNamespace = "$namespace.test"
+
+      compileSdk = libs.versions.compileSdk.get().toInt()
+      minSdk = libs.versions.minSdk.get().toInt()
+
+      withHostTestBuilder {
+      }.configure {
+      }
+
+      withDeviceTestBuilder {
+        sourceSetTreeName = "test"
+      }.configure {
+        instrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+
+        // Disable transition and rotation animations.
+        animationsDisabled = true
+      }
+    }
+  }
   if (targets == "kmp" || targets == "js") {
     js(IR) { browser() }
   }
-}
 
-dependencies {
-  commonMainApi(libs.kotlin.jdk6)
-  commonMainApi(libs.kotlinx.coroutines.core)
-  // For Snapshot.
-  commonMainApi(libs.squareup.okio)
+  sourceSets {
+    commonMain {
+      dependencies {
+        api(libs.kotlin.jdk6)
+        api(libs.kotlinx.coroutines.core)
+        // For Snapshot.
+        api(libs.squareup.okio)
+      }
+    }
 
-  commonTestImplementation(libs.kotlinx.atomicfu)
-  commonTestImplementation(libs.kotlinx.coroutines.test.common)
-  commonTestImplementation(libs.kotlin.test.core)
+    commonTest {
+      dependencies {
+        implementation(libs.kotlinx.atomicfu)
+        implementation(libs.kotlinx.coroutines.test.common)
+        implementation(libs.kotlin.test.core)
+      }
+    }
+
+    getByName("androidHostTest") {
+      dependencies {
+        implementation(libs.robolectric)
+        implementation(libs.robolectric.annotations)
+      }
+    }
+  }
 }

workflow-core/dependencies/androidRuntimeClasspath.txt

@@ -0,0 +1,11 @@
+com.squareup.okio:okio-jvm:3.3.0
+com.squareup.okio:okio:3.3.0
+org.jetbrains.kotlin:kotlin-bom:2.0.21
+org.jetbrains.kotlin:kotlin-stdlib-common:2.0.21
+org.jetbrains.kotlin:kotlin-stdlib-jdk7:2.0.21
+org.jetbrains.kotlin:kotlin-stdlib-jdk8:2.0.21
+org.jetbrains.kotlin:kotlin-stdlib:2.0.21
+org.jetbrains.kotlinx:kotlinx-coroutines-bom:1.7.3
+org.jetbrains.kotlinx:kotlinx-coroutines-core-jvm:1.7.3
+org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3
+org.jetbrains:annotations:23.0.0

workflow-core/src/androidHostTest/kotlin/com/squareup/workflow1/SnapshotParcelsTest.kt

@@ -0,0 +1,24 @@
+package com.squareup.workflow1
+
+import android.os.Bundle
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+
+@RunWith(RobolectricTestRunner::class)
+class SnapshotParcelsTest {
+
+  @Test fun parcelableToSnapshot_savesAndRestores() {
+    val snapshot = Bundle().apply {
+      putString("key", "value")
+    }.toSnapshot()
+    val restored = snapshot.toParcelable<Bundle>()
+
+    assertNotNull(restored)
+    assertTrue(restored.containsKey("key"))
+    assertEquals("value", restored.getString("key"))
+  }
+}

workflow-core/src/jvmMain/kotlin/com/squareup/workflow1/CommonUniqueClassName.kt renamed to workflow-core/src/androidMain/kotlin/com/squareup/workflow1/CommonUniqueClassName.android.kt

@@ -0,0 +1,48 @@
+package com.squareup.workflow1
+
+import android.os.Build.VERSION
+import android.os.Build.VERSION_CODES
+import android.os.Parcel
+import android.os.Parcelable
+import okio.ByteString
+
+/**
+ * Wraps receiver in a [Snapshot] suitable for use with [StatefulWorkflow].
+ * Intended to allow use of `@Parcelize`.
+ *
+ * Read the [Parcelable] back with [toParcelable].
+ */
+public fun Parcelable.toSnapshot(): Snapshot = Snapshot.write { bufferedSink ->
+  val parcel = Parcel.obtain()
+  parcel.writeParcelable(this, 0)
+  val byteArray = parcel.marshall()
+  bufferedSink.write(byteArray)
+  parcel.recycle()
+}
+
+/**
+ * Returns a [Parcelable] previously wrapped with [toSnapshot], or `null` if the receiver is empty.
+ */
+public inline fun <reified T : Parcelable> Snapshot.toParcelable(): T? =
+  bytes.toParcelable<T>()
+
+public inline fun <reified T : Parcelable> ByteString.toParcelable(): T? =
+  toParcelable(T::class.java)
+
+@PublishedApi
+internal fun <T : Parcelable> ByteString.toParcelable(targetClass: Class<T>): T? {
+  if (size == 0) return null
+
+  val parcel = Parcel.obtain()
+  val byteArray = toByteArray()
+  parcel.unmarshall(byteArray, 0, byteArray.size)
+  parcel.setDataPosition(0)
+  val rtn = if (VERSION.SDK_INT >= VERSION_CODES.TIRAMISU) {
+    parcel.readParcelable(Snapshot::class.java.classLoader, targetClass)!!
+  } else {
+    @Suppress("DEPRECATION")
+    parcel.readParcelable(Snapshot::class.java.classLoader)!!
+  }
+  parcel.recycle()
+  return rtn
+}

workflow-core/src/androidMain/kotlin/com/squareup/workflow1/SnapshotParcels.kt

@@ -0,0 +1,7 @@
+package com.squareup.workflow1
+
+import kotlin.reflect.KClass
+
+internal actual fun commonUniqueClassName(kClass: KClass<*>): String {
+  return kClass.qualifiedName ?: kClass.toString()
+}