3 files changed, 29 insertions, 11 deletions

diff --git a/core/src/main/kotlin/plugability/DokkaContext.kt b/core/src/main/kotlin/plugability/DokkaContext.kt
index 0d110f85..e6286f0b 100644
--- a/core/src/main/kotlin/plugability/DokkaContext.kt
+++ b/core/src/main/kotlin/plugability/DokkaContext.kt
@@ -105,7 +105,7 @@ private class DokkaContextConfigurationImpl(
             AskDefault.Never -> actions(point).orEmpty()
             AskDefault.Always -> actions(point).orEmpty() + DefaultExtensions.get(point, this)
             AskDefault.WhenEmpty ->
-                actions(point)?.takeIf { it.isNotEmpty() } ?: DefaultExtensions?.get(point, this)
+                actions(point)?.takeIf { it.isNotEmpty() } ?: DefaultExtensions.get(point, this)
         } as List<T>
 
     private fun <E : ExtensionPoint<*>> actions(point: E) = extensions[point]?.map { it.action.get(this) }
@@ -119,7 +119,7 @@ private class DokkaContextConfigurationImpl(
     fun install(plugin: DokkaPlugin) {
         plugins[plugin::class] = plugin
         plugin.context = this
-        plugin.internalInstall(this)
+        plugin.internalInstall(this, this.configuration)
     }
 
     override fun addExtensionDependencies(extension: Extension<*>) {
diff --git a/core/src/main/kotlin/plugability/DokkaPlugin.kt b/core/src/main/kotlin/plugability/DokkaPlugin.kt
index 3f82000d..1fcbd934 100644
--- a/core/src/main/kotlin/plugability/DokkaPlugin.kt
+++ b/core/src/main/kotlin/plugability/DokkaPlugin.kt
@@ -1,5 +1,6 @@
 package org.jetbrains.dokka.plugability
 
+import org.jetbrains.dokka.DokkaConfiguration
 import kotlin.properties.ReadOnlyProperty
 import kotlin.reflect.KProperty
 import kotlin.reflect.KProperty1
@@ -36,10 +37,10 @@ abstract class DokkaPlugin {
         }.also { thisRef.extensionDelegates += property }
     }
 
-    internal fun internalInstall(ctx: DokkaContextConfiguration) {
+    internal fun internalInstall(ctx: DokkaContextConfiguration, configuration: DokkaConfiguration) {
         extensionDelegates.asSequence()
             .filterIsInstance<KProperty1<DokkaPlugin, Extension<*>>>() // should be always true
             .map { it.get(this) }
-            .forEach { ctx.addExtensionDependencies(it) }
+            .forEach { if(it.condition.invoke(configuration)) ctx.addExtensionDependencies(it) }
     }
 }
\ No newline at end of file
diff --git a/core/src/main/kotlin/plugability/extensions.kt b/core/src/main/kotlin/plugability/extensions.kt
index 42bf3900..4cbb61eb 100644
--- a/core/src/main/kotlin/plugability/extensions.kt
+++ b/core/src/main/kotlin/plugability/extensions.kt
@@ -1,5 +1,7 @@
 package org.jetbrains.dokka.plugability
 
+import org.jetbrains.dokka.DokkaConfiguration
+
 data class ExtensionPoint<T : Any> internal constructor(
     internal val pluginClass: String,
     internal val pointName: String
@@ -12,7 +14,8 @@ abstract class Extension<T : Any> internal constructor(
     internal val pluginClass: String,
     internal val extensionName: String,
     internal val action: LazyEvaluated<T>,
-    internal val ordering: (OrderDsl.() -> Unit)? = null
+    internal val ordering: (OrderDsl.() -> Unit)? = null,
+    internal val condition: DokkaConfiguration.() -> Boolean = { true }
 ) {
     override fun toString() = "Extension: $pluginClass/$extensionName"
 
@@ -21,6 +24,8 @@ abstract class Extension<T : Any> internal constructor(
         else false
 
     override fun hashCode() = listOf(pluginClass, extensionName).hashCode()
+
+    abstract fun setCondition(condition: (DokkaConfiguration.() -> Boolean)): Extension<T>
 }
 
 class ExtensionOrdered<T : Any> internal constructor(
@@ -28,27 +33,37 @@ class ExtensionOrdered<T : Any> internal constructor(
     pluginClass: String,
     extensionName: String,
     action: LazyEvaluated<T>,
-    ordering: (OrderDsl.() -> Unit)
+    ordering: (OrderDsl.() -> Unit),
+    condition: DokkaConfiguration.() -> Boolean = { true }
 ) : Extension<T>(
     extensionPoint,
     pluginClass,
     extensionName,
     action,
-    ordering
-)
+    ordering,
+    condition
+) {
+    override fun setCondition(condition: DokkaConfiguration.() -> Boolean) =
+        ExtensionOrdered(extensionPoint, pluginClass, extensionName, action, ordering!!, condition)
+}
 
 class ExtensionUnordered<T : Any> internal constructor(
     extensionPoint: ExtensionPoint<T>,
     pluginClass: String,
     extensionName: String,
-    action: LazyEvaluated<T>
+    action: LazyEvaluated<T>,
+    condition: DokkaConfiguration.() -> Boolean = { true }
 ) : Extension<T>(
     extensionPoint,
     pluginClass,
     extensionName,
     action,
-    null
-)
+    null,
+    condition
+) {
+    override fun setCondition(condition: DokkaConfiguration.() -> Boolean) =
+        ExtensionUnordered(extensionPoint, pluginClass, extensionName, action, condition)
+}
 
 internal data class Ordering(val previous: Set<Extension<*>>, val following: Set<Extension<*>>)
 
@@ -66,6 +81,8 @@ class ExtendingDSL(private val pluginClass: String, private val extensionName: S
 
     infix fun <T: Any> ExtensionUnordered<T>.order(block: OrderDsl.() -> Unit) =
         ExtensionOrdered(extensionPoint, pluginClass, extensionName, action, block)
+
+    infix fun <T : Any> Extension<T>.applyIf(condition: DokkaConfiguration.() -> Boolean): Extension<T> = this.setCondition(condition)
 }
 
 @ExtensionsDsl