Cleans up page mergers and moves them to base plugin

6 files changed, 115 insertions, 8 deletions

diff --git a/plugins/base/src/main/kotlin/DokkaBase.kt b/plugins/base/src/main/kotlin/DokkaBase.kt
index bafd30ff..ed23d77e 100644
--- a/plugins/base/src/main/kotlin/DokkaBase.kt
+++ b/plugins/base/src/main/kotlin/DokkaBase.kt
@@ -4,11 +4,17 @@ import org.jetbrains.dokka.CoreExtensions
 import org.jetbrains.dokka.base.transformers.descriptors.DefaultDescriptorToDocumentationTranslator
 import org.jetbrains.dokka.base.transformers.documentables.DefaultDocumentableMerger
 import org.jetbrains.dokka.base.transformers.documentables.DefaultDocumentablesToPageTranslator
+import org.jetbrains.dokka.base.transformers.pages.merger.FallbackPageMergerStrategy
+import org.jetbrains.dokka.base.transformers.pages.merger.PageMergerStrategy
+import org.jetbrains.dokka.base.transformers.pages.merger.PageNodeMerger
+import org.jetbrains.dokka.base.transformers.pages.merger.SameMethodNamePageMergerStrategy
 import org.jetbrains.dokka.base.transformers.psi.DefaultPsiToDocumentationTranslator
 import org.jetbrains.dokka.plugability.DokkaPlugin
 import org.jetbrains.dokka.renderers.html.HtmlRenderer
 
 class DokkaBase: DokkaPlugin() {
+    val pageMergerStrategy by extensionPoint<PageMergerStrategy>()
+
     val descriptorToDocumentationTranslator by extending(isFallback = true) {
         CoreExtensions.descriptorToDocumentationTranslator providing ::DefaultDescriptorToDocumentationTranslator
     }
@@ -25,7 +31,21 @@ class DokkaBase: DokkaPlugin() {
         CoreExtensions.documentablesToPageTranslator with DefaultDocumentablesToPageTranslator
     }
 
+    val pageMerger by extending {
+        CoreExtensions.pageTransformer providing { ctx -> PageNodeMerger(ctx[pageMergerStrategy]) }
+    }
+
+    val fallbackMerger by extending {
+        pageMergerStrategy providing { ctx -> FallbackPageMergerStrategy(ctx.logger) }
+    }
+
+    val sameMethodNameMerger by extending {
+        pageMergerStrategy with SameMethodNamePageMergerStrategy order {
+            before(fallbackMerger)
+        }
+    }
+
     val htmlRenderer by extending {
-        CoreExtensions.renderer providing ::HtmlRenderer
+        CoreExtensions.renderer providing ::HtmlRenderer applyIf { format == "html" }
     }
 }
\ No newline at end of file
diff --git a/plugins/base/src/main/kotlin/transformers/pages/merger/FallbackPageMergerStrategy.kt b/plugins/base/src/main/kotlin/transformers/pages/merger/FallbackPageMergerStrategy.kt
new file mode 100644
index 00000000..df0c27ee
--- /dev/null
+++ b/plugins/base/src/main/kotlin/transformers/pages/merger/FallbackPageMergerStrategy.kt
@@ -0,0 +1,12 @@
+package org.jetbrains.dokka.base.transformers.pages.merger
+
+import org.jetbrains.dokka.pages.PageNode
+import org.jetbrains.dokka.utilities.DokkaLogger
+
+class FallbackPageMergerStrategy(private val logger: DokkaLogger) : PageMergerStrategy {
+    override fun tryMerge(pages: List<PageNode>, path: List<String>): List<PageNode> {
+        val renderedPath = path.joinToString(separator = "/")
+        if (pages.size != 1) logger.warn("For $renderedPath: expected 1 page, but got ${pages.size}")
+        return listOf(pages.first())
+    }
+}
\ No newline at end of file
diff --git a/plugins/base/src/main/kotlin/transformers/pages/merger/PageMergerStrategy.kt b/plugins/base/src/main/kotlin/transformers/pages/merger/PageMergerStrategy.kt
new file mode 100644
index 00000000..b73b17e0
--- /dev/null
+++ b/plugins/base/src/main/kotlin/transformers/pages/merger/PageMergerStrategy.kt
@@ -0,0 +1,9 @@
+package org.jetbrains.dokka.base.transformers.pages.merger
+
+import org.jetbrains.dokka.pages.PageNode
+
+interface PageMergerStrategy {
+
+    fun tryMerge(pages: List<PageNode>, path: List<String>): List<PageNode>
+
+}
\ No newline at end of file
diff --git a/plugins/base/src/main/kotlin/transformers/pages/merger/PageNodeMerger.kt b/plugins/base/src/main/kotlin/transformers/pages/merger/PageNodeMerger.kt
new file mode 100644
index 00000000..5ecf8d9b
--- /dev/null
+++ b/plugins/base/src/main/kotlin/transformers/pages/merger/PageNodeMerger.kt
@@ -0,0 +1,29 @@
+package org.jetbrains.dokka.base.transformers.pages.merger
+
+import org.jetbrains.dokka.pages.PageNode
+import org.jetbrains.dokka.pages.RootPageNode
+import org.jetbrains.dokka.transformers.pages.PageNodeTransformer
+
+class PageNodeMerger(private val strategies: Iterable<PageMergerStrategy>) : PageNodeTransformer {
+    override fun invoke(input: RootPageNode): RootPageNode =
+        input.modified(children = input.children.map { it.mergeChildren(emptyList()) })
+
+    private fun PageNode.mergeChildren(path: List<String>): PageNode = children.groupBy { it.name }
+        .map { (n, v) -> mergePageNodes(v, path + n) }
+        .let { pages ->
+            modified(children = pages.map { it.assertSingle(path) }.map { it.mergeChildren(path + it.name) })
+        }
+
+    private fun mergePageNodes(pages: List<PageNode>, path: List<String>): List<PageNode> =
+        strategies.fold(pages) { acc, strategy -> tryMerge(strategy, acc, path) }
+
+    private fun tryMerge(strategy: PageMergerStrategy, pages: List<PageNode>, path: List<String>) =
+        if (pages.size > 1) strategy.tryMerge(pages, path) else pages
+}
+
+private fun <T> Iterable<T>.assertSingle(path: List<String>): T = try {
+        single()
+    } catch (e: Exception) {
+        val renderedPath = path.joinToString(separator = "/")
+        throw IllegalStateException("Page merger is missconfigured. Error for $renderedPath: ${e.message}")
+    }
\ No newline at end of file
diff --git a/plugins/base/src/main/kotlin/transformers/pages/merger/SameMethodNamePageMergerStrategy.kt b/plugins/base/src/main/kotlin/transformers/pages/merger/SameMethodNamePageMergerStrategy.kt
new file mode 100644
index 00000000..fef55dd2
--- /dev/null
+++ b/plugins/base/src/main/kotlin/transformers/pages/merger/SameMethodNamePageMergerStrategy.kt
@@ -0,0 +1,35 @@
+package org.jetbrains.dokka.base.transformers.pages.merger
+
+import org.jetbrains.dokka.pages.*
+
+object SameMethodNamePageMergerStrategy : PageMergerStrategy {
+    override fun tryMerge(pages: List<PageNode>, path: List<String>): List<PageNode> {
+        val name = pages.first().name
+        val members = pages.filterIsInstance<MemberPageNode>()
+        val others = pages.filterNot { it is MemberPageNode }
+
+        val resChildren = members.flatMap { it.children }.distinct()
+        val dri = members.flatMap { it.dri }.toSet()
+        val dci = DCI(
+            dri = dri,
+            kind = members.first().content.dci.kind
+        )
+
+        val merged = MemberPageNode(
+            dri = dri,
+            name = name,
+            children = resChildren,
+            content = asGroup(
+                dci,
+                members.map { it.content }),
+            documentable = null
+        )
+
+        return others + listOf(merged)
+    }
+
+    fun asGroup(dci: DCI, nodes: List<ContentNode>): ContentGroup {
+        val n = nodes.first()
+        return ContentGroup(nodes, dci, n.platforms, n.style, n.extras)
+    }
+}
\ No newline at end of file
diff --git a/plugins/base/src/test/kotlin/pageMerger/PageNodeMergerTest.kt b/plugins/base/src/test/kotlin/pageMerger/PageNodeMergerTest.kt
index 88e57ddb..c6076d54 100644
--- a/plugins/base/src/test/kotlin/pageMerger/PageNodeMergerTest.kt
+++ b/plugins/base/src/test/kotlin/pageMerger/PageNodeMergerTest.kt
@@ -4,15 +4,15 @@ import org.jetbrains.dokka.CoreExtensions
 import org.jetbrains.dokka.pages.ContentPage
 import org.jetbrains.dokka.pages.PageNode
 import org.jetbrains.dokka.plugability.DokkaPlugin
-import org.jetbrains.dokka.transformers.pages.DefaultPageMergerStrategy
-import org.jetbrains.dokka.transformers.pages.SameMethodNamePageMergerStrategy
+import org.jetbrains.dokka.base.transformers.pages.merger.SameMethodNamePageMergerStrategy
 import org.jetbrains.dokka.utilities.DokkaLogger
+import org.junit.Ignore
 import org.junit.Test
 import testApi.testRunner.AbstractCoreTest
 
 class PageNodeMergerTest : AbstractCoreTest() {
 
-    object SameNameStrategy : DokkaPlugin() {
+    /* object SameNameStrategy : DokkaPlugin() {
         val strategy by extending { CoreExtensions.pageMergerStrategy with SameMethodNamePageMergerStrategy }
     }
 
@@ -36,6 +36,7 @@ class PageNodeMergerTest : AbstractCoreTest() {
 
         override fun report() = TODO()
     }
+     */
 
     @Test
     fun sameNameStrategyTest() {
@@ -61,8 +62,8 @@ class PageNodeMergerTest : AbstractCoreTest() {
             |   fun test(str: String): String = str
             |}
         """.trimMargin(),
-            configuration,
-            pluginOverrides = listOf(SameNameStrategy)
+            configuration/*,
+            pluginOverrides = listOf(SameNameStrategy)*/
         ) {
             pagesTransformationStage = {
                 val allChildren = it.childrenRec().filterIsInstance<ContentPage>()
@@ -78,6 +79,7 @@ class PageNodeMergerTest : AbstractCoreTest() {
         }
     }
 
+    @Ignore("TODO: reenable when we have infrastructure for turning off extensions")
     @Test
     fun defaultStrategyTest() {
         val strList: MutableList<String> = mutableListOf()
@@ -103,8 +105,8 @@ class PageNodeMergerTest : AbstractCoreTest() {
             |   fun test(str: String): String = str
             |}
         """.trimMargin(),
-            configuration,
-            pluginOverrides = listOf(DefaultStrategy(strList))
+            configuration/*,
+            pluginOverrides = listOf(DefaultStrategy(strList)) */
         ) {
             pagesTransformationStage = { root ->
                 val allChildren = root.childrenRec().filterIsInstance<ContentPage>()