Cache identifier

gradle.properties

@@ -8,7 +8,7 @@ android.useAndroidX=true
 systemProp.org.gradle.internal.publish.checksums.insecure=true
 
 GROUP=com.squareup.workflow1
-VERSION_NAME=1.8.0-beta13-SNAPSHOT
+VERSION_NAME=1.8.0-beta13-cache2-SNAPSHOT
 
 POM_DESCRIPTION=Square Workflow
 

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

@@ -1,13 +1,17 @@
 package com.squareup.sample.compose.hellocomposeworkflow
 
 import androidx.compose.runtime.Composable
+import com.squareup.workflow1.IdCacheable
 import com.squareup.workflow1.RenderContext
 import com.squareup.workflow1.Sink
 import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.Workflow
+import com.squareup.workflow1.WorkflowIdentifier
+import com.squareup.workflow1.computeIdentifier
 import com.squareup.workflow1.ui.ViewEnvironment
 import com.squareup.workflow1.ui.WorkflowUiExperimentalApi
 import com.squareup.workflow1.ui.compose.ComposeScreen
+import kotlin.LazyThreadSafetyMode.NONE
 
 /**
  * A stateless [Workflow] that [renders][RenderingContent] itself as a [Composable] function.
@@ -29,7 +33,7 @@ import com.squareup.workflow1.ui.compose.ComposeScreen
  */
 @WorkflowUiExperimentalApi
 abstract class ComposeWorkflow<in PropsT, out OutputT : Any> :
-  Workflow<PropsT, OutputT, ComposeScreen> {
+  Workflow<PropsT, OutputT, ComposeScreen>, IdCacheable {
 
   /**
    * Renders [props] by emitting Compose UI. This function will be called to update the UI whenever
@@ -48,6 +52,12 @@ abstract class ComposeWorkflow<in PropsT, out OutputT : Any> :
 
   override fun asStatefulWorkflow(): StatefulWorkflow<PropsT, *, OutputT, ComposeScreen> =
     ComposeWorkflowImpl(this)
+
+  override val cachedIdentifier: WorkflowIdentifier by lazy(
+    mode = NONE
+  ) {
+    computeIdentifier()
+  }
 }
 
 /**

workflow-core/api/workflow-core.api

@@ -48,6 +48,10 @@ public final class com/squareup/workflow1/BaseRenderContext$DefaultImpls {
 	public static synthetic fun renderChild$default (Lcom/squareup/workflow1/BaseRenderContext;Lcom/squareup/workflow1/Workflow;Ljava/lang/Object;Ljava/lang/String;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Ljava/lang/Object;
 }
 
+public abstract interface class com/squareup/workflow1/IdCacheable {
+	public abstract fun getCachedIdentifier ()Lcom/squareup/workflow1/WorkflowIdentifier;
+}
+
 public abstract interface class com/squareup/workflow1/ImpostorWorkflow {
 	public abstract fun describeRealIdentifier ()Ljava/lang/String;
 	public abstract fun getRealIdentifier ()Lcom/squareup/workflow1/WorkflowIdentifier;
@@ -115,9 +119,10 @@ public final class com/squareup/workflow1/Snapshots {
 	public static final fun writeUtf8WithLength (Lokio/BufferedSink;Ljava/lang/String;)Lokio/BufferedSink;
 }
 
-public abstract class com/squareup/workflow1/StatefulWorkflow : com/squareup/workflow1/Workflow {
+public abstract class com/squareup/workflow1/StatefulWorkflow : com/squareup/workflow1/IdCacheable, com/squareup/workflow1/Workflow {
 	public fun <init> ()V
 	public final fun asStatefulWorkflow ()Lcom/squareup/workflow1/StatefulWorkflow;
+	public fun getCachedIdentifier ()Lcom/squareup/workflow1/WorkflowIdentifier;
 	public abstract fun initialState (Ljava/lang/Object;Lcom/squareup/workflow1/Snapshot;)Ljava/lang/Object;
 	public fun onPropsChanged (Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
 	public abstract fun render (Ljava/lang/Object;Ljava/lang/Object;Lcom/squareup/workflow1/StatefulWorkflow$RenderContext;)Ljava/lang/Object;
@@ -141,9 +146,10 @@ public final class com/squareup/workflow1/StatefulWorkflow$RenderContext : com/s
 	public fun runningSideEffect (Ljava/lang/String;Lkotlin/jvm/functions/Function2;)V
 }
 
-public abstract class com/squareup/workflow1/StatelessWorkflow : com/squareup/workflow1/Workflow {
+public abstract class com/squareup/workflow1/StatelessWorkflow : com/squareup/workflow1/IdCacheable, com/squareup/workflow1/Workflow {
 	public fun <init> ()V
 	public final fun asStatefulWorkflow ()Lcom/squareup/workflow1/StatefulWorkflow;
+	public fun getCachedIdentifier ()Lcom/squareup/workflow1/WorkflowIdentifier;
 	public abstract fun render (Ljava/lang/Object;Lcom/squareup/workflow1/StatelessWorkflow$RenderContext;)Ljava/lang/Object;
 }
 
@@ -283,6 +289,7 @@ public final class com/squareup/workflow1/Workflows {
 	public static synthetic fun action$default (Lcom/squareup/workflow1/StatelessWorkflow;Ljava/lang/String;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lcom/squareup/workflow1/WorkflowAction;
 	public static synthetic fun action$default (Ljava/lang/String;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lcom/squareup/workflow1/WorkflowAction;
 	public static final fun applyTo (Lcom/squareup/workflow1/WorkflowAction;Ljava/lang/Object;Ljava/lang/Object;)Lkotlin/Pair;
+	public static final fun computeIdentifier (Lcom/squareup/workflow1/Workflow;)Lcom/squareup/workflow1/WorkflowIdentifier;
 	public static final fun contraMap (Lcom/squareup/workflow1/Sink;Lkotlin/jvm/functions/Function1;)Lcom/squareup/workflow1/Sink;
 	public static final fun getIdentifier (Lcom/squareup/workflow1/Workflow;)Lcom/squareup/workflow1/WorkflowIdentifier;
 	public static final fun mapRendering (Lcom/squareup/workflow1/Workflow;Lkotlin/jvm/functions/Function1;)Lcom/squareup/workflow1/Workflow;

workflow-core/src/commonMain/kotlin/com/squareup/workflow1/IdCacheable.kt

@@ -0,0 +1,14 @@
+package com.squareup.workflow1
+
+/**
+ * If your Workflow caches its [WorkflowIdentifier] (to avoid frequent lookups) then implement
+ * this interface. Note that [StatefulWorkflow] and [StatelessWorkflow] already implement this,
+ * so you only need to do so if you do not extend one of those classes.
+ *
+ * If your Workflow is an [ImpostorWorkflow] use the lazy delegate pattern that [StatefulWorkflow]
+ * and [StatelessWorkflow] do in order to initialize everything in the proper order.
+ */
+public interface IdCacheable {
+
+  public val cachedIdentifier: WorkflowIdentifier
+}

workflow-core/src/commonMain/kotlin/com/squareup/workflow1/ImpostorWorkflow.kt

@@ -18,7 +18,7 @@ import kotlin.jvm.JvmName
 public interface ImpostorWorkflow {
   /**
    * The [WorkflowIdentifier] of another workflow to be combined with the identifier of this
-   * workflow, as obtained by [Workflow.identifier].
+   * workflow, as obtained by [Workflow.computeIdentifier].
    *
    * For workflows that implement operators, this should be the identifier of the upstream
    * [Workflow] that this workflow wraps.

workflow-core/src/commonMain/kotlin/com/squareup/workflow1/StatefulWorkflow.kt

@@ -6,6 +6,7 @@ package com.squareup.workflow1
 
 import com.squareup.workflow1.StatefulWorkflow.RenderContext
 import com.squareup.workflow1.WorkflowAction.Companion.toString
+import kotlin.LazyThreadSafetyMode.NONE
 import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName
 
@@ -69,7 +70,7 @@ public abstract class StatefulWorkflow<
   StateT,
   out OutputT,
   out RenderingT
-  > : Workflow<PropsT, OutputT, RenderingT> {
+  > : Workflow<PropsT, OutputT, RenderingT>, IdCacheable {
 
   public inner class RenderContext internal constructor(
     baseContext: BaseRenderContext<PropsT, StateT, OutputT>
@@ -129,6 +130,18 @@ public abstract class StatefulWorkflow<
     context: RenderContext
   ): RenderingT
 
+  /**
+   * Use a lazy delegate so that any [ImpostorWorkflow.realIdentifier] will have been computed
+   * before this is initialized and cached.
+   *
+   * We use [LazyThreadSafetyMode.NONE] because access to these identifiers is thread-confined.
+   */
+  override val cachedIdentifier: WorkflowIdentifier by lazy(
+    mode = NONE
+  ) {
+    computeIdentifier()
+  }
+
   /**
    * Called whenever the state changes to generate a new [Snapshot] of the state.
    *

workflow-core/src/commonMain/kotlin/com/squareup/workflow1/StatelessWorkflow.kt

@@ -3,6 +3,7 @@
 
 package com.squareup.workflow1
 
+import kotlin.LazyThreadSafetyMode.NONE
 import kotlin.jvm.JvmMultifileClass
 import kotlin.jvm.JvmName
 
@@ -24,7 +25,7 @@ import kotlin.jvm.JvmName
  * @see StatefulWorkflow
  */
 public abstract class StatelessWorkflow<in PropsT, out OutputT, out RenderingT> :
-  Workflow<PropsT, OutputT, RenderingT> {
+  Workflow<PropsT, OutputT, RenderingT>, IdCacheable {
 
   @Suppress("UNCHECKED_CAST")
   public inner class RenderContext internal constructor(
@@ -57,6 +58,18 @@ public abstract class StatelessWorkflow<in PropsT, out OutputT, out RenderingT>
     context: RenderContext
   ): RenderingT
 
+  /**
+   * Use a lazy delegate so that any [ImpostorWorkflow.realIdentifier] will have been computed
+   * before this is initialized and cached.
+   *
+   * We use [LazyThreadSafetyMode.NONE] because access to these identifiers is thread-confined.
+   */
+  override val cachedIdentifier: WorkflowIdentifier by lazy(
+    mode = NONE
+  ) {
+    computeIdentifier()
+  }
+
   /**
    * Satisfies the [Workflow] interface by wrapping `this` in a [StatefulWorkflow] with `Unit`
    * state.

workflow-core/src/commonMain/kotlin/com/squareup/workflow1/Workflow.kt

@@ -120,7 +120,7 @@ Workflow<PropsT, OutputT, FromRenderingT>.mapRendering(
   transform: (FromRenderingT) -> ToRenderingT
 ): Workflow<PropsT, OutputT, ToRenderingT> =
   object : StatelessWorkflow<PropsT, OutputT, ToRenderingT>(), ImpostorWorkflow {
-    override val realIdentifier: WorkflowIdentifier get() = [email protected]
+    override val realIdentifier: WorkflowIdentifier = [email protected]
 
     override fun render(
       renderProps: PropsT,

workflow-core/src/commonMain/kotlin/com/squareup/workflow1/WorkflowIdentifier.kt

@@ -145,17 +145,32 @@ public class WorkflowIdentifier internal constructor(
 
 /**
  * The [WorkflowIdentifier] that identifies this [Workflow].
+ *
+ * This can carry some cost if the Workflow class does not implement [IdCacheable]. Note that
+ * [StatelessWorkflow] and [StatefulWorkflow] do implement the caching.
  */
-public val Workflow<*, *, *>.identifier: WorkflowIdentifier
+public inline val Workflow<*, *, *>.identifier: WorkflowIdentifier
   get() {
-    val maybeImpostor = this as? ImpostorWorkflow
-    return WorkflowIdentifier(
-      type = Snapshottable(this::class),
-      proxiedIdentifier = maybeImpostor?.realIdentifier,
-      description = maybeImpostor?.let { it::describeRealIdentifier }
-    )
+    return when (this) {
+      is IdCacheable -> cachedIdentifier
+      else -> computeIdentifier()
+    }
   }
 
+/**
+ * Compute the [WorkflowIdentifier] for this Workflow. Any [IdCacheable] Workflow should call this
+ * and then store the value in the cachedIdentifier property so as to prevent
+ * the extra work needed to create the [WorkflowIdentifier] and look up the class name each time.
+ */
+public fun Workflow<*, *, *>.computeIdentifier(): WorkflowIdentifier {
+  val maybeImpostor = this as? ImpostorWorkflow
+  return WorkflowIdentifier(
+    type = Snapshottable(this::class),
+    proxiedIdentifier = maybeImpostor?.realIdentifier,
+    description = maybeImpostor?.let { it::describeRealIdentifier }
+  )
+}
+
 /**
  * Creates a [WorkflowIdentifier] that is not capable of being snapshotted and will cause any
  * [ImpostorWorkflow] workflow identified by it to also not be snapshotted.

workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/WorkflowInterceptorTest.kt

@@ -212,7 +212,8 @@ internal class WorkflowInterceptorTest {
 
   private val Workflow<*, *, *>.session: WorkflowSession
     get() = object : WorkflowSession {
-      override val identifier: WorkflowIdentifier = [email protected]
+      override val identifier: WorkflowIdentifier
+        get() = [email protected]
       override val renderKey: String = ""
       override val sessionId: Long = 0
       override val parent: WorkflowSession? = null

workflow-testing/src/test/java/com/squareup/workflow1/testing/RealRenderTesterTest.kt

@@ -14,6 +14,7 @@ import com.squareup.workflow1.WorkflowIdentifier
 import com.squareup.workflow1.WorkflowOutput
 import com.squareup.workflow1.action
 import com.squareup.workflow1.asWorker
+import com.squareup.workflow1.computeIdentifier
 import com.squareup.workflow1.contraMap
 import com.squareup.workflow1.identifier
 import com.squareup.workflow1.renderChild
@@ -1473,32 +1474,32 @@ internal class RealRenderTesterTest {
 
   @Test fun `realTypeMatchesExpectation() matches mockito mock of expected interface`() {
     val expected = TestWorkflowInterface::class.workflowIdentifier
-    val actual = mock<TestWorkflowInterface>().identifier
+    val actual = mock<TestWorkflowInterface>().computeIdentifier()
     assertTrue(actual.realTypeMatchesExpectation(expected))
   }
 
   @Test fun `realTypeMatchesExpectation() matches mockito mock of expected abstract class`() {
     val expected = ExpectedWorkflowClass::class.workflowIdentifier
-    val actual = mock<ExpectedWorkflowClass>().identifier
+    val actual = mock<ExpectedWorkflowClass>().computeIdentifier()
     assertTrue(actual.realTypeMatchesExpectation(expected))
   }
 
   @Test fun `realTypeMatchesExpectation() doesn't match mockito mock of unexpected interface`() {
     val expected = TestWorkflowInterface::class.workflowIdentifier
-    val actual = mock<Workflow<Unit, Nothing, Unit>>().identifier
+    val actual = mock<Workflow<Unit, Nothing, Unit>>().computeIdentifier()
     assertFalse(actual.realTypeMatchesExpectation(expected))
   }
 
   @Test
   fun `realTypeMatchesExpectation() doesn't match mockito mock of unexpected abstract class`() {
     val expected = ExpectedWorkflowClass::class.workflowIdentifier
-    val actual = mock<UnexpectedWorkflowClass>().identifier
+    val actual = mock<UnexpectedWorkflowClass>().computeIdentifier()
     assertFalse(actual.realTypeMatchesExpectation(expected))
   }
 
   @Test fun `realTypeMatchesExpectation() handles mockk mocks`() {
     val expected = TestWorkflowInterface::class.workflowIdentifier
-    val actual = mockk<TestWorkflowInterface>().identifier
+    val actual = mockk<TestWorkflowInterface>().computeIdentifier()
     assertTrue(actual.realTypeMatchesExpectation(expected))
   }