Implement hierarchy helper functions

compose-destinations-codegen/src/main/java/com/ramcosta/composedestinations/codegen/templates/NavGraphsObjectTemplate.kt

@@ -9,6 +9,7 @@ import com.ramcosta.composedestinations.codegen.templates.core.FileTemplate
 import com.ramcosta.composedestinations.codegen.templates.core.setOfImportable
 
 const val NAV_GRAPHS_PLACEHOLDER = "[NAV_GRAPHS_PLACEHOLDER]"
+const val NAV_GRAPHS_LIST_PLACEHOLDER = "[NAV_GRAPHS_LIST_PLACEHOLDER]"
 
 val navGraphsObjectTemplate = FileTemplate(
     packageStatement = "package $codeGenBasePackageName",
@@ -24,6 +25,8 @@ val navGraphsObjectTemplate = FileTemplate(
 object $GENERATED_NAV_GRAPHS_OBJECT {
 
 $NAV_GRAPHS_PLACEHOLDER
+
+$NAV_GRAPHS_LIST_PLACEHOLDER
 }
 """.trimIndent()
 )

compose-destinations-codegen/src/main/java/com/ramcosta/composedestinations/codegen/templates/SingleModuleExtensionsTemplate.kt

@@ -44,6 +44,35 @@ data class $GENERATED_NAV_GRAPH(
     override val destinationsByRoute: Map<String, $typeAliasDestination> = destinations.associateBy { it.route }
 }
 
+/**
+ * Return the parent of this [Destination][DestinationSpec] by searching through the [NavGraph]s in
+ * the [NavGraphs] object.
+ *
+ * This variable should **NEVER** be null. If `first { ... }` throws a [NoSuchElementException], it
+ * means this [Destination][DestinationSpec] somehow isn't part of a [NavGraph].
+ */
+val $CORE_DESTINATION_SPEC<*>.parent: $GENERATED_NAV_GRAPH
+    get() = $GENERATED_NAV_GRAPHS_OBJECT.all.first {
+        it.destinations.contains(this)
+    }
+
+/**
+ * Return the parent of this [NavGraphSpec] by searching through the [NavGraph]s'
+ * [NavGraph.nestedNavGraphs] in the [NavGraphs] object.
+ */
+val $CORE_NAV_GRAPH_SPEC.parent: $GENERATED_NAV_GRAPH?
+    get() = $GENERATED_NAV_GRAPHS_OBJECT.all.find {
+        it.nestedNavGraphs.contains(this)
+    }
+
+/**
+ * Provides a sequence of the [DestinationSpec]'s hierarchy. The hierarchy starts with this
+ * [DestinationSpec]'s [parent][DestinationSpec.parent] [NavGraph], then that graph's parent, and up 
+ * the hierarchy until you've reached the root navigation graph.
+ */
+val $CORE_DESTINATION_SPEC<*>.hierarchy: Sequence<$GENERATED_NAV_GRAPH>
+    get() = generateSequence(this.parent) { it.parent }
+
 /**
  * If this [Route] is a [$typeAliasDestination], returns it
  *

compose-destinations-codegen/src/main/java/com/ramcosta/composedestinations/codegen/writers/sub/LegacyNavGraphsSingleObjectWriter.kt

@@ -8,10 +8,12 @@ import com.ramcosta.composedestinations.codegen.model.GeneratedDestination
 import com.ramcosta.composedestinations.codegen.model.Importable
 import com.ramcosta.composedestinations.codegen.model.NavGraphGeneratingParams
 import com.ramcosta.composedestinations.codegen.model.NavGraphInfo
+import com.ramcosta.composedestinations.codegen.templates.NAV_GRAPHS_LIST_PLACEHOLDER
 import com.ramcosta.composedestinations.codegen.templates.NAV_GRAPHS_PLACEHOLDER
 import com.ramcosta.composedestinations.codegen.templates.navGraphsObjectTemplate
 import com.ramcosta.composedestinations.codegen.writers.helpers.ImportableHelper
 import com.ramcosta.composedestinations.codegen.writers.helpers.writeSourceFile
+import java.util.Collections.addAll
 
 class LegacyNavGraphsSingleObjectWriter(
     private val codeGenerator: CodeOutputStreamMaker,
@@ -31,6 +33,7 @@ class LegacyNavGraphsSingleObjectWriter(
             importableHelper = importableHelper,
             sourceCode = navGraphsObjectTemplate.sourceCode
                 .replace(NAV_GRAPHS_PLACEHOLDER, navGraphsDeclaration(navGraphsParams))
+                .replace(NAV_GRAPHS_LIST_PLACEHOLDER, navGraphsListDeclaration(navGraphsParams))
         )
 
         return navGraphsParams
@@ -79,6 +82,19 @@ class LegacyNavGraphsSingleObjectWriter(
 
     }
 
+    private fun navGraphsListDeclaration(navGraphsParams: List<NavGraphGeneratingParams>): String {
+        val navGraphsAnchor = "[NAV_GRAPHS]"
+        val navGraphFieldNames = navGraphsParams.joinToString(",\n\t\t") {
+            navGraphFieldName(it.route)
+        }
+        return """
+       |    val all: List<$GENERATED_NAV_GRAPH> = listOf(
+       |        $navGraphsAnchor
+       |    )
+        """.trimMargin()
+            .replace(navGraphsAnchor, navGraphFieldNames)
+    }
+
     private fun requireOptInAnnotations(navGraphRequireOptInImportables: Set<Importable>): String {
         val code = StringBuilder()
 

compose-destinations-codegen/src/main/java/com/ramcosta/composedestinations/codegen/writers/sub/NavGraphsSingleObjectWriter.kt

@@ -5,6 +5,7 @@ import com.ramcosta.composedestinations.codegen.commons.*
 import com.ramcosta.composedestinations.codegen.facades.CodeOutputStreamMaker
 import com.ramcosta.composedestinations.codegen.facades.Logger
 import com.ramcosta.composedestinations.codegen.model.*
+import com.ramcosta.composedestinations.codegen.templates.NAV_GRAPHS_LIST_PLACEHOLDER
 import com.ramcosta.composedestinations.codegen.templates.NAV_GRAPHS_PLACEHOLDER
 import com.ramcosta.composedestinations.codegen.templates.navGraphsObjectTemplate
 import com.ramcosta.composedestinations.codegen.writers.helpers.ImportableHelper
@@ -64,7 +65,7 @@ class NavGraphsSingleObjectWriter(
                             nestedNavGraphs.forEach {
                                 addAll(destinationsByNavGraphParams[it]!!.requireOptInAnnotationClassTypes())
                             }
-                        },
+                        }
                 )
             }
 
@@ -86,6 +87,7 @@ class NavGraphsSingleObjectWriter(
             importableHelper = importableHelper,
             sourceCode = navGraphsObjectTemplate.sourceCode
                 .replace(NAV_GRAPHS_PLACEHOLDER, navGraphsDeclaration(orderedNavGraphGenParams))
+                .replace(NAV_GRAPHS_LIST_PLACEHOLDER, navGraphsListDeclaration(orderedNavGraphGenParams))
 
         )
     }
@@ -130,6 +132,19 @@ class NavGraphsSingleObjectWriter(
 
     }
 
+    private fun navGraphsListDeclaration(navGraphsParams: List<NavGraphGeneratingParams>): String {
+        val navGraphsAnchor = "[NAV_GRAPHS]"
+        val navGraphFieldNames = navGraphsParams.joinToString(",\n\t\t") {
+            navGraphFieldName(it.route)
+        }
+        return """
+       |    val all: List<$GENERATED_NAV_GRAPH> = listOf(
+       |        $navGraphsAnchor
+       |    )
+        """.trimMargin()
+            .replace(navGraphsAnchor, navGraphFieldNames)
+    }
+
     private fun destinationsInsideList(destinations: List<GeneratedDestination>): String {
         val code = StringBuilder()
         destinations.forEachIndexed { i, it ->