Add a draft version of divergent rendering

2 files changed, 68 insertions, 4 deletions

diff --git a/core/src/main/kotlin/pages/ContentNodes.kt b/core/src/main/kotlin/pages/ContentNodes.kt
index bb669199..e7f027e3 100644
--- a/core/src/main/kotlin/pages/ContentNodes.kt
+++ b/core/src/main/kotlin/pages/ContentNodes.kt
@@ -90,7 +90,7 @@ data class ContentResolvedLink(
         copy(extra = newExtras)
 }
 
-/** All links that do not need to be resolved */
+/** Embedded resources like images */
 data class ContentEmbeddedResource(
     override val children: List<ContentNode> = emptyList(),
     val address: String,
@@ -144,6 +144,43 @@ data class ContentGroup(
     override fun withNewExtras(newExtras: PropertyContainer<ContentNode>): ContentGroup = copy(extra = newExtras)
 }
 
+/**
+ * @property groupName is used for finding and copying [ContentDivergentInstance]s when merging [ContentPage]s
+ */
+data class ContentDivergentGroup(
+    override val children: List<ContentDivergentInstance>,
+    override val dci: DCI,
+    override val style: Set<Style>,
+    override val extra: PropertyContainer<ContentNode>,
+    val groupID: GroupID,
+    val implicitlySourceSetHinted: Boolean = true
+) : ContentComposite {
+    data class GroupID(val name: String)
+
+    override val sourceSets: Set<SourceSetData>
+        get() = children.flatMap { it.sourceSets }.distinct().toSet()
+
+    override fun withNewExtras(newExtras: PropertyContainer<ContentNode>): ContentDivergentGroup =
+        copy(extra = newExtras)
+}
+
+/** Instance of a divergent content */
+data class ContentDivergentInstance(
+    val before: ContentNode?,
+    val divergent: ContentNode,
+    val after: ContentNode?,
+    override val dci: DCI,
+    override val sourceSets: Set<SourceSetData>,
+    override val style: Set<Style>,
+    override val extra: PropertyContainer<ContentNode> = PropertyContainer.empty()
+) : ContentComposite {
+    override val children: List<ContentNode>
+        get() = listOfNotNull(before, divergent, after)
+
+    override fun withNewExtras(newExtras: PropertyContainer<ContentNode>): ContentDivergentInstance =
+        copy(extra = newExtras)
+}
+
 data class PlatformHintedContent(
     val inner: ContentNode,
     override val sourceSets: Set<SourceSetData>
@@ -163,9 +200,6 @@ data class PlatformHintedContent(
         throw UnsupportedOperationException("This method should not be called on this PlatformHintedContent")
 }
 
-/** All extras */
-interface Extra
-
 interface Style
 interface Kind
 
diff --git a/core/src/main/kotlin/pages/utils.kt b/core/src/main/kotlin/pages/utils.kt
new file mode 100644
index 00000000..5292dea1
--- /dev/null
+++ b/core/src/main/kotlin/pages/utils.kt
@@ -0,0 +1,30 @@
+package org.jetbrains.dokka.pages
+
+import kotlin.reflect.KClass
+
+inline fun <reified T : ContentNode, R : ContentNode> R.mapTransform(noinline operation: (T) -> T): R =
+    mapTransform(T::class, operation)
+
+@PublishedApi
+@Suppress("UNCHECKED_CAST")
+internal fun <T : ContentNode, R : ContentNode> R.mapTransform(type: KClass<T>, operation: (T) -> T): R {
+    if (this::class == type) {
+        return operation(this as T) as R
+    }
+    val new = when (this) {
+        is ContentGroup -> this.copy(children.map { it.mapTransform(type, operation) })
+        is ContentHeader -> this.copy(children.map { it.mapTransform(type, operation) })
+        is ContentCode -> this.copy(children.map { it.mapTransform(type, operation) })
+        is ContentTable -> this.copy(children.map { it.mapTransform(type, operation) })
+        is ContentList -> this.copy(children.map { it.mapTransform(type, operation) })
+        is ContentDivergentGroup -> this.copy(children.map { it.mapTransform(type, operation) })
+        is ContentDivergentInstance -> this.copy(
+            before = before?.mapTransform(type, operation),
+            divergent = divergent.mapTransform(type, operation),
+            after = after?.mapTransform(type, operation)
+        )
+        is PlatformHintedContent -> this.copy(inner.mapTransform(type, operation))
+        else -> this
+    }
+    return new as R
+}