[Kotlin Project Model] Add compiler plugin support

libraries/tools/kotlin-project-model/src/main/kotlin/KotlinAttributes.kt

@@ -5,6 +5,10 @@
 
 package org.jetbrains.kotlin.project.model
 
+// TODO: Add better Kotlin Variant Attributes management
+//  Ideally we should respect the nature of Attributes and express values in form of Complete Lattice
+//  Moreover we can add support for default and most used Value Types (eg. Enums)
+
 open class KotlinAttributeKey(
     val uniqueName: String
 ) {
@@ -15,6 +19,7 @@ open class KotlinAttributeKey(
         uniqueName.hashCode()
 }
 
+// TODO: Introduce ENUM
 object KotlinPlatformTypeAttribute : KotlinAttributeKey("org.jetbrains.kotlin.platform.type") {
     const val JVM = "jvm"
     const val ANDROID_JVM = "androidJvm"

libraries/tools/kotlin-project-model/src/main/kotlin/KotlinModule.kt

@@ -42,6 +42,8 @@ interface KotlinModule {
     val variants: Iterable<KotlinModuleVariant>
         get() = fragments.filterIsInstance<KotlinModuleVariant>()
 
+    val plugins: Iterable<KpmCompilerPlugin>
+
     // TODO: isSynthetic?
 }
 
@@ -50,5 +52,7 @@ open class BasicKotlinModule(
 ) : KotlinModule {
     override val fragments = mutableListOf<BasicKotlinModuleFragment>()
 
+    override val plugins = mutableListOf<KpmCompilerPlugin>()
+
     override fun toString(): String = "module $moduleIdentifier"
 }

libraries/tools/kotlin-project-model/src/main/kotlin/KotlinModuleFragment.kt

@@ -45,6 +45,7 @@ val KotlinModuleFragment.refinesClosure: Set<KotlinModuleFragment>
         visit(this@refinesClosure)
     }
 
+val KotlinModuleVariant.platform get() = variantAttributes[KotlinPlatformTypeAttribute]
 
 open class BasicKotlinModuleFragment(
     override val containingModule: KotlinModule,

libraries/tools/kotlin-project-model/src/main/kotlin/KpmCompilerPlugin.kt

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.project.model
+
+/**
+ * Adapts Kotlin Compiler Plugin for Multiplatform Kotlin Project Model
+ * Build System uses this interface to identify applicable plugin artifacts and its options
+ * before executing actual Kotlin Compilation
+ */
+interface KpmCompilerPlugin {
+
+    /**
+     * Returns [PluginData] when applicable for [fragment] compilation
+     * Returns [null] if not applicable
+     */
+    fun forMetadataCompilation(fragment: KotlinModuleFragment): PluginData?
+
+    /**
+     * Returns [PluginData] when applicable for [fragment] compilation
+     * Returns [null] if not applicable
+     */
+    fun forNativeMetadataCompilation(fragment: KotlinModuleFragment): PluginData?
+
+    /**
+     * Returns [PluginData] when applicable for [variant] compilation
+     * Returns [null] if not applicable
+     */
+    fun forPlatformCompilation(variant: KotlinModuleVariant): PluginData?
+}
+
+/**
+ * Plugin data can be used for changing some compilation request
+ */
+data class PluginData(
+    val pluginId: String,
+    val artifact: ArtifactCoordinates,
+    val options: List<PluginOption>
+) {
+    // FIXME: (?) Is it common thing or gradle/maven centric?
+    data class ArtifactCoordinates(
+        val group: String,
+        val artifact: String,
+        val version: String? = null
+    )
+
+    data class PluginOption(
+        val key: String,
+        val value: String
+    )
+}
+
+// TODO: It should be part of "Compilation Process": KotlinModule.compilationRequestFor(METADATA | PLATFORM) -> CompilationRequest
+//  But there is no such thing at the moment :)
+fun KotlinModuleFragment.metadataCompilationPluginData(): List<PluginData> =
+    containingModule
+        .plugins
+        .mapNotNull { plugin -> plugin.forMetadataCompilation(this) }
+
+fun KotlinModuleFragment.nativeMetadataCompilationPluginData(): List<PluginData> =
+    containingModule
+        .plugins
+        .mapNotNull { plugin -> plugin.forNativeMetadataCompilation(this) }
+
+fun KotlinModuleVariant.platformCompilationPluginData(): List<PluginData> =
+    containingModule
+        .plugins
+        .mapNotNull { plugin -> plugin.forPlatformCompilation(this) }
+
+/**
+ * Represents trivial Compiler Plugin adapter for Kotlin Project Model
+ * Where Compiler Plugin can have common and native artifacts
+ */
+abstract class BasicKpmCompilerPlugin : KpmCompilerPlugin {
+
+    abstract val pluginId: String
+
+    protected abstract fun commonPluginArtifact(): PluginData.ArtifactCoordinates?
+
+    protected abstract fun nativePluginArtifact(): PluginData.ArtifactCoordinates?
+
+    protected abstract val pluginOptions: List<PluginData.PluginOption>
+
+
+    override fun forMetadataCompilation(fragment: KotlinModuleFragment) = pluginDataOrNull(commonPluginArtifact())
+
+    override fun forNativeMetadataCompilation(fragment: KotlinModuleFragment) = pluginDataOrNull(nativePluginArtifact())
+
+    override fun forPlatformCompilation(variant: KotlinModuleVariant) =
+        when (variant.platform) {
+            KotlinPlatformTypeAttribute.NATIVE -> nativePluginArtifact()
+            else -> commonPluginArtifact()
+        }.let(::pluginDataOrNull)
+
+    private fun pluginDataOrNull(artifact: PluginData.ArtifactCoordinates?) =
+        if (artifact != null) PluginData(pluginId, artifact, pluginOptions)
+        else null
+}
+
+