Created NavigationStateStore

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

@@ -0,0 +1,15 @@
+package com.chrynan.navigation.compose
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.State
+import androidx.compose.runtime.collectAsState
+import com.chrynan.navigation.NavigationState
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Converts the [NavigationState.changes] of this [NavigationState] to a Jetpack Compose [State] so that every change
+ * causes a recomposition of the calling [Composable] function.
+ */
+@Composable
+fun <T> NavigationState<T>.collectAsState(): State<T> =
+ (this.changes as? StateFlow<T>)?.collectAsState() ?: this.changes.collectAsState(initial = this.initial)

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

@@ -16,7 +16,7 @@ import kotlinx.serialization.Serializable
  * @see [Navigator.navigate]
  */
 @Serializable
-sealed class NavigationEvent private constructor() {
+sealed class NavigationEvent<D : NavigationDestination, C : NavigationContext<D>> private constructor() {
 
  /**
  * The [Instant] that the event occurred.
@@ -35,14 +35,14 @@ sealed class NavigationEvent private constructor() {
  */
  @Serializable
  @SerialName(value = "back")
- class Back internal constructor(
+ class Back<D : NavigationDestination, C : NavigationContext<D>> internal constructor(
  @SerialName(value = "instant") override val instant: Instant = Clock.System.now(),
  @SerialName(value = "kind") val kind: Kind
- ) : NavigationEvent() {
+ ) : NavigationEvent<D, C>() {
 
  override fun equals(other: Any?): Boolean {
  if (this === other) return true
- if (other !is Back) return false
+ if (other !is Back<*, *>) return false
 
  if (instant != other.instant) return false
 
@@ -96,14 +96,14 @@ sealed class NavigationEvent private constructor() {
  */
  @Serializable
  @SerialName(value = "destination")
- class Destination<D : NavigationDestination> internal constructor(
+ class Destination<D : NavigationDestination, C : NavigationContext<D>> internal constructor(
  @SerialName(value = "instant") override val instant: Instant = Clock.System.now(),
  @SerialName(value = "destination") val destination: D
- ) : NavigationEvent() {
+ ) : NavigationEvent<D, C>() {
 
  override fun equals(other: Any?): Boolean {
  if (this === other) return true
- if (other !is Destination<*>) return false
+ if (other !is Destination<*, *>) return false
 
  if (instant != other.instant) return false
 
@@ -131,7 +131,7 @@ sealed class NavigationEvent private constructor() {
  class Context<D : NavigationDestination, C : NavigationContext<D>> internal constructor(
  @SerialName(value = "instant") override val instant: Instant = Clock.System.now(),
  @SerialName(value = "context") val context: C
- ) : NavigationEvent() {
+ ) : NavigationEvent<D, C>() {
 
  override fun equals(other: Any?): Boolean {
  if (this === other) return true

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

@@ -34,6 +34,8 @@ sealed interface NavigationState<T> {
  * purposes of listening to state changes.
  */
  val changes: Flow<T>
+
+ companion object
 }
 
 /**
@@ -51,12 +53,14 @@ internal sealed interface MutableNavigationState<T> : NavigationState<T> {
  * Resets the state back to its [initial] value. This will cause the [initial] value to be emitted to [changes].
  */
  fun reset()
+
+ companion object
 }
 
 /**
  * Creates a [MutableNavigationState] instance.
  */
-internal fun <T> mutableNavigationStateOf(initial: T): NavigationState<T> =
+internal fun <T> mutableNavigationStateOf(initial: T): MutableNavigationState<T> =
  StateFlowMutableNavigationState(initial = initial)
 
 /**

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

@@ -0,0 +1,79 @@
+@file:Suppress("unused")
+
+package com.chrynan.navigation
+
+/**
+ * Represents a store of navigation state information that is useful for a [Navigator].
+ */
+interface NavigationStateStore<Destination : NavigationDestination, Context : NavigationContext<Destination>> {
+
+ /**
+ * A [NavigationState] of [NavigationEvent]s.
+ */
+ val event: NavigationState<NavigationEvent<Destination, Context>?>
+
+ /**
+ * A [NavigationState] of [NavigationDestination]s.
+ */
+ val destination: NavigationState<Destination>
+
+ /**
+ * A [NavigationState] of [NavigationContext]s.
+ */
+ val context: NavigationState<Context>
+}
+
+/**
+ * A mutable version of a [NavigationStateStore].
+ */
+internal interface MutableNavigationStateStore<Destination : NavigationDestination, Context : NavigationContext<Destination>> :
+ NavigationStateStore<Destination, Context> {
+
+ /**
+ * Dispatches the provided navigation [event] which mutates the underlying state values.
+ */
+ fun dispatch(event: NavigationEvent<Destination, Context>)
+
+ /**
+ * Resets the underlying state values back to their initial values.
+ */
+ fun reset()
+}
+
+/**
+ * Creates a [MutableNavigationStateStore] instance with the provided [initialContext] value.
+ */
+internal fun <Destination : NavigationDestination, Context : NavigationContext<Destination>> mutableNavigationStateStoreOf(
+ initialContext: Context
+): MutableNavigationStateStore<Destination, Context> =
+ MapBasedMutableNavigationStateStore(initialContext = initialContext)
+
+/**
+ * A [MutableNavigationStateStore] implementation that stores [NavigationContext]s and their associated
+ * [NavigationDestination] [Stack]s in an in-memory [Map].
+ */
+internal class MapBasedMutableNavigationStateStore<Destination : NavigationDestination, Context : NavigationContext<Destination>> internal constructor(
+ initialContext: Context
+) : MutableNavigationStateStore<Destination, Context> {
+
+ override val event = mutableNavigationStateOf<NavigationEvent<Destination, Context>?>(initial = null)
+ override val destination = mutableNavigationStateOf(initial = initialContext.initialDestination)
+ override val context = mutableNavigationStateOf(initial = initialContext)
+
+ private val map = mutableMapOf(initialContext to mutableStackOf(initialContext.initialDestination))
+
+ override fun dispatch(event: NavigationEvent<Destination, Context>) {
+ this.event.update(event)
+
+ TODO("Not yet implemented")
+ }
+
+ override fun reset() {
+ event.reset()
+ destination.reset()
+ context.reset()
+
+ map.clear()
+ map[context.initial] = mutableStackOf(context.initial.initialDestination)
+ }
+}