Fixed Serialization Issue #9

navigation-compose/build.gradle.kts

@@ -41,9 +41,8 @@ kotlin {
                 implementation(compose.ui)
                 implementation(compose.foundation)
 
-                implementation(KotlinX.serialization.core)
-                implementation("com.chrynan.parcelable:parcelable-core:_")
-                implementation("com.chrynan.parcelable:parcelable-compose:_")
+                api("com.chrynan.parcelable:parcelable-core:_")
+                api("com.chrynan.parcelable:parcelable-compose:_")
             }
         }
         if (isBuildingOnOSX()) {

navigation-compose/src/commonMain/kotlin/com.chrynan.navigation.compose/RememberComposeNavigatorUtils.kt

@@ -147,7 +147,7 @@ fun <Destination : NavigationDestination, Context : NavigationContext<Destinatio
 inline fun <reified Destination : NavigationDestination> rememberSavableNavigator(
     initialDestination: Destination,
     parcelable: Parcelable = Parcelable.Default,
-    destinationSerializer: KSerializer<Destination> = Parcelable.serializersModule.serializer(),
+    destinationSerializer: KSerializer<Destination> = parcelable.serializersModule.serializer(),
     duplicateDestinationStrategy: NavigationStrategy.DuplicateDestination = NavigationStrategy.DuplicateDestination.ALLOW_DUPLICATES,
     backwardsNavigationStrategy: NavigationStrategy.BackwardsNavigation = NavigationStrategy.BackwardsNavigation.IN_CONTEXT,
     destinationRetentionStrategy: NavigationStrategy.DestinationRetention = NavigationStrategy.DestinationRetention.RETAIN
@@ -210,8 +210,8 @@ inline fun <reified Destination : NavigationDestination> rememberSavableNavigato
 inline fun <reified Destination : NavigationDestination, reified Context : NavigationContext<Destination>> rememberSavableNavigator(
     initialContext: Context,
     parcelable: Parcelable = Parcelable.Default,
-    destinationSerializer: KSerializer<Destination> = Parcelable.serializersModule.serializer(),
-    contextSerializer: KSerializer<Context> = Parcelable.serializersModule.serializer(),
+    destinationSerializer: KSerializer<Destination> = parcelable.serializersModule.serializer(),
+    contextSerializer: KSerializer<Context> = parcelable.serializersModule.serializer(),
     duplicateDestinationStrategy: NavigationStrategy.DuplicateDestination = NavigationStrategy.DuplicateDestination.ALLOW_DUPLICATES,
     backwardsNavigationStrategy: NavigationStrategy.BackwardsNavigation = NavigationStrategy.BackwardsNavigation.IN_CONTEXT,
     destinationRetentionStrategy: NavigationStrategy.DestinationRetention = NavigationStrategy.DestinationRetention.RETAIN

navigation-core/build.gradle.kts

@@ -49,7 +49,7 @@ kotlin {
                 implementation(Kotlin.stdlib.common)
 
                 implementation(KotlinX.coroutines.core)
-                implementation(KotlinX.serialization.core)
+                api(KotlinX.serialization.core)
             }
         }
 

navigation-core/src/commonMain/kotlin/com.chrynan.navigation/NavigationEvent.kt

@@ -2,8 +2,10 @@
 
 package com.chrynan.navigation
 
-import kotlinx.serialization.SerialName
-import kotlinx.serialization.Serializable
+import kotlinx.serialization.*
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 
 /**
  * Represents a navigation event that is sent to a [Navigator] to coordinate the navigation between UI components, such
@@ -14,7 +16,7 @@ import kotlinx.serialization.Serializable
  *
  * @see [Navigator.dispatch]
  */
-@Serializable
+@Serializable(with = NavigationEventSerializer::class)
 sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>> private constructor() {
 
     /**
@@ -29,6 +31,16 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
      */
     abstract val direction: Direction
 
+    /**
+     * The type of [NavigationEvent] that occurred.
+     */
+    abstract val type: Type
+
+    /**
+     * Creates a serializable [Snapshot] instance of this [NavigationEvent].
+     */
+    internal abstract fun toSnapshot(): Snapshot<D, C>
+
     /**
      * Represents a direction for a [NavigationEvent]. A [NavigationEvent] can either be a [FORWARDS] direction event,
      * meaning the change is added to a [Stack], or a [BACKWARDS] direction event, meaning the change causes a removal
@@ -50,6 +62,28 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
         FORWARDS(serialName = "forwards")
     }
 
+    @Serializable
+    enum class Type(val serialName: String) {
+
+        /**
+         * Corresponds to the [NavigationEvent.Backward] type.
+         */
+        @SerialName(value = "backwards")
+        BACKWARDS(serialName = "backwards"),
+
+        /**
+         * Corresponds to the [NavigationEvent.Forward.Context] type.
+         */
+        @SerialName(value = "context")
+        CONTEXT(serialName = "context"),
+
+        /**
+         * Corresponds to the [NavigationEvent.Forward.Destination] type.
+         */
+        @SerialName(value = "destination")
+        DESTINATION(serialName = "destination")
+    }
+
     /**
      * A [NavigationEvent] that represents a reversal of a previous navigation event. A [Backward] navigation event can be
      * used to go to the previous [NavigationDestination] within the current [NavigationContext], or going back to a
@@ -59,13 +93,22 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
      * occurred. **Note:** This is not safe to persist or use between system reboots.
      */
     @Serializable
-    @SerialName(value = "back")
+    @SerialName(value = "backwards")
     class Backward<D : NavigationDestination, C : NavigationContext<D>> internal constructor(
         @SerialName(value = "instant") override val elapsedMilliseconds: Long = elapsedSystemTime().inWholeMilliseconds
     ) : NavigationEvent<D, C>() {
 
         override val direction: Direction = Direction.BACKWARDS
 
+        @Transient
+        override val type: Type = Type.BACKWARDS
+
+        override fun toSnapshot(): Snapshot<D, C> = Snapshot(
+            type = type,
+            direction = direction,
+            elapsedMilliseconds = elapsedMilliseconds
+        )
+
         override fun equals(other: Any?): Boolean {
             if (this === other) return true
             if (other !is Backward<*, *>) return false
@@ -85,7 +128,7 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
      * reversed by a [Backward] event. There are two forward navigation events: [Destination] representing a change in
      * destination on the current context stack, and [Context] representing a change in the context.
      */
-    @Serializable
+    @Serializable(with = NavigationEventForwardSerializer::class)
     @SerialName(value = "forward")
     sealed class Forward<D : NavigationDestination, C : NavigationContext<D>> private constructor() :
         NavigationEvent<D, C>() {
@@ -107,6 +150,16 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
             @SerialName(value = "destination") val destination: D
         ) : Forward<D, C>() {
 
+            @Transient
+            override val type: Type = Type.DESTINATION
+
+            override fun toSnapshot(): Snapshot<D, C> = Snapshot(
+                type = type,
+                direction = direction,
+                elapsedMilliseconds = elapsedMilliseconds,
+                destination = destination
+            )
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) return true
                 if (other !is Destination<*, *>) return false
@@ -140,6 +193,16 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
             @SerialName(value = "context") val context: C
         ) : Forward<D, C>() {
 
+            @Transient
+            override val type: Type = Type.CONTEXT
+
+            override fun toSnapshot(): Snapshot<D, C> = Snapshot(
+                type = type,
+                direction = direction,
+                elapsedMilliseconds = elapsedMilliseconds,
+                context = context
+            )
+
             override fun equals(other: Any?): Boolean {
                 if (this === other) return true
                 if (other !is Context<*, *>) return false
@@ -160,5 +223,161 @@ sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>
         }
     }
 
+    @Serializable
+    internal class Snapshot<Destination : NavigationDestination, Context : NavigationContext<Destination>>(
+        @SerialName(value = "type") val type: Type,
+        @SerialName(value = "direction") val direction: Direction,
+        @SerialName(value = "elapsed_milliseconds") val elapsedMilliseconds: Long,
+        @SerialName(value = "destination") val destination: Destination? = null,
+        @SerialName(value = "context") val context: Context? = null
+    ) {
+
+        override fun equals(other: Any?): Boolean {
+            if (this === other) return true
+            if (other !is Snapshot<*, *>) return false
+
+            if (type != other.type) return false
+            if (direction != other.direction) return false
+            if (elapsedMilliseconds != other.elapsedMilliseconds) return false
+            if (destination != other.destination) return false
+
+            return context == other.context
+        }
+
+        override fun hashCode(): Int {
+            var result = type.hashCode()
+            result = 31 * result + direction.hashCode()
+            result = 31 * result + elapsedMilliseconds.hashCode()
+            result = 31 * result + (destination?.hashCode() ?: 0)
+            result = 31 * result + (context?.hashCode() ?: 0)
+            return result
+        }
+
+        override fun toString(): String =
+            "Snapshot(" +
+                    "type=$type, " +
+                    "direction=$direction, " +
+                    "elapsedMilliseconds=$elapsedMilliseconds, " +
+                    "destination=$destination, " +
+                    "context=$context)"
+    }
+
     companion object
 }
+
+/**
+ * Creates a [NavigationEvent] instance with the provided [NavigationEvent.Snapshot].
+ */
+internal fun <Destination : NavigationDestination, Context : NavigationContext<Destination>> NavigationEvent(
+    snapshot: NavigationEvent.Snapshot<Destination, Context>
+): NavigationEvent<Destination, Context> =
+    when (snapshot.type) {
+        NavigationEvent.Type.BACKWARDS -> NavigationEvent.Backward(elapsedMilliseconds = snapshot.elapsedMilliseconds)
+        NavigationEvent.Type.DESTINATION -> NavigationEvent.Forward.Destination(
+            elapsedMilliseconds = snapshot.elapsedMilliseconds,
+            destination = snapshot.destination!!
+        )
+
+        NavigationEvent.Type.CONTEXT -> NavigationEvent.Forward.Context(
+            elapsedMilliseconds = snapshot.elapsedMilliseconds,
+            context = snapshot.context!!
+        )
+    }
+
+internal class NavigationEventSerializer<Destination : NavigationDestination, Context : NavigationContext<Destination>>(
+    destinationSerializer: KSerializer<Destination>,
+    contextSerializer: KSerializer<Context>
+) : KSerializer<NavigationEvent<Destination, Context>> {
+
+    private val delegateSerializer = NavigationEvent.Snapshot.serializer(
+        destinationSerializer,
+        contextSerializer
+    )
+
+    override val descriptor: SerialDescriptor = destinationSerializer.descriptor
+
+    override fun serialize(encoder: Encoder, value: NavigationEvent<Destination, Context>) {
+        encoder.encodeSerializableValue(
+            serializer = delegateSerializer,
+            value = value.toSnapshot()
+        )
+    }
+
+    override fun deserialize(decoder: Decoder): NavigationEvent<Destination, Context> {
+        val snapshot = decoder.decodeSerializableValue(deserializer = delegateSerializer)
+
+        return NavigationEvent(snapshot = snapshot)
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is NavigationEventSerializer<*, *>) return false
+
+        if (delegateSerializer != other.delegateSerializer) return false
+
+        return descriptor == other.descriptor
+    }
+
+    override fun hashCode(): Int {
+        var result = delegateSerializer.hashCode()
+        result = 31 * result + descriptor.hashCode()
+        return result
+    }
+
+    override fun toString(): String =
+        "NavigationEventSerializer(" +
+                "delegateSerializer=$delegateSerializer, " +
+                "descriptor=$descriptor)"
+}
+
+internal class NavigationEventForwardSerializer<Destination : NavigationDestination, Context : NavigationContext<Destination>>(
+    destinationSerializer: KSerializer<Destination>,
+    contextSerializer: KSerializer<Context>
+) : KSerializer<NavigationEvent.Forward<Destination, Context>> {
+
+    private val delegateSerializer = NavigationEvent.Snapshot.serializer(
+        destinationSerializer,
+        contextSerializer
+    )
+
+    override val descriptor: SerialDescriptor = destinationSerializer.descriptor
+
+    override fun serialize(encoder: Encoder, value: NavigationEvent.Forward<Destination, Context>) {
+        encoder.encodeSerializableValue(
+            serializer = delegateSerializer,
+            value = value.toSnapshot()
+        )
+    }
+
+    override fun deserialize(decoder: Decoder): NavigationEvent.Forward<Destination, Context> {
+        val snapshot = decoder.decodeSerializableValue(deserializer = delegateSerializer)
+
+        val event = NavigationEvent(snapshot = snapshot)
+
+        if (event !is NavigationEvent.Forward) {
+            throw SerializationException("${this::class.simpleName} only works for ${NavigationEvent.Forward::class.simpleName} types.")
+        }
+
+        return event
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is NavigationEventForwardSerializer<*, *>) return false
+
+        if (delegateSerializer != other.delegateSerializer) return false
+
+        return descriptor == other.descriptor
+    }
+
+    override fun hashCode(): Int {
+        var result = delegateSerializer.hashCode()
+        result = 31 * result + descriptor.hashCode()
+        return result
+    }
+
+    override fun toString(): String =
+        "NavigationEventForwardSerializer(" +
+                "delegateSerializer=$delegateSerializer, " +
+                "descriptor=$descriptor)"
+}