Working extensions in plugins

1 files changed, 55 insertions, 3 deletions

diff --git a/core/src/main/kotlin/plugability/DokkaPlugin.kt b/core/src/main/kotlin/plugability/DokkaPlugin.kt
index 2654bcee..60ca245c 100644
--- a/core/src/main/kotlin/plugability/DokkaPlugin.kt
+++ b/core/src/main/kotlin/plugability/DokkaPlugin.kt
@@ -1,6 +1,58 @@
 package org.jetbrains.dokka.plugability
 
-interface DokkaPlugin {
-    val name: String
-    fun install(context: DokkaContext)
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+import kotlin.reflect.KProperty1
+import kotlin.reflect.KTypeProjection
+import kotlin.reflect.full.createInstance
+import kotlin.reflect.full.createType
+import kotlin.reflect.full.declaredMemberProperties
+import kotlin.reflect.jvm.isAccessible
+import kotlin.reflect.jvm.jvmErasure
+
+private typealias ExtensionDelegate<T> = ReadOnlyProperty<DokkaPlugin, Extension<T>>
+
+abstract class DokkaPlugin {
+    private val extensionDelegates = mutableListOf<KProperty<*>>()
+
+    @PublishedApi
+    internal var context: DokkaContext? = null
+
+    protected open fun install(context: DokkaContext) {}
+
+    protected inline fun <reified T : DokkaPlugin> plugin(): T =
+        context?.plugin(T::class) as? T ?: T::class.createInstance().also { it.context = this.context }
+
+    protected fun <T : Any> extensionPoint() =
+        object : ReadOnlyProperty<DokkaPlugin, ExtensionPoint<T>> {
+            override fun getValue(thisRef: DokkaPlugin, property: KProperty<*>) = ExtensionPoint<T>(
+                thisRef::class.qualifiedName ?: throw AssertionError("Plugin must be named class"),
+                property.name
+            )
+        }
+
+    protected fun <T: Any> extending(definition: ExtendingDSL.() -> Extension<T>) = ExtensionProvider(definition)
+
+    protected class ExtensionProvider<T: Any> internal constructor(
+        private val definition: ExtendingDSL.() -> Extension<T>
+    ) {
+        operator fun provideDelegate(thisRef: DokkaPlugin, property: KProperty<*>) = lazy {
+            ExtendingDSL(
+                thisRef::class.qualifiedName ?: throw AssertionError("Plugin must be named class"),
+                property.name
+            ).definition()
+        }.also { thisRef.extensionDelegates += property }
+    }
+
+    internal fun internalInstall(ctx: DokkaContext) {
+        context = ctx
+        install(ctx)
+
+        extensionDelegates.asSequence()
+            .filterIsInstance<KProperty1<DokkaPlugin, Extension<*>>>() // always true
+            .map { it.get(this) }
+            .forEach { ctx.addExtension(it) }
+    }
+
+
 }
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