Gradle, native: Add a DSL shortcut for iOS, watchsOS and tvOS

This patch adds a group of shortcut DSL methods allowing a user to
create simulator and device targets for Apple platforms along with
corresponding common source set(s) in one command. iOS, tvOS and
watchOS targets are supported.

Issue #KT-33856 fixed

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinMultiplatformExtension.kt

@@ -13,7 +13,11 @@ import org.jetbrains.kotlin.gradle.plugin.*
 import org.jetbrains.kotlin.gradle.plugin.mpp.*
 import org.jetbrains.kotlin.gradle.utils.isGradleVersionAtLeast
 
-open class KotlinMultiplatformExtension : KotlinProjectExtension(), KotlinTargetContainerWithPresetFunctions {
+open class KotlinMultiplatformExtension :
+    KotlinProjectExtension(),
+    KotlinTargetContainerWithPresetFunctions,
+    KotlinTargetContainerWithNativeShortcuts
+{
     override lateinit var presets: NamedDomainObjectCollection<KotlinTargetPreset<*>>
         internal set
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinProjectExtension.kt

@@ -22,6 +22,7 @@ import org.gradle.api.Project
 import org.gradle.api.internal.plugins.DslObject
 import org.gradle.util.ConfigureUtil
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
+import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSetContainer
 import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsCompilation
@@ -50,11 +51,11 @@ internal val Project.multiplatformExtensionOrNull: KotlinMultiplatformExtension?
 internal val Project.multiplatformExtension: KotlinMultiplatformExtension
     get() = extensions.getByName(KOTLIN_PROJECT_EXTENSION_NAME) as KotlinMultiplatformExtension
 
-open class KotlinProjectExtension {
+open class KotlinProjectExtension: KotlinSourceSetContainer {
     val experimental: ExperimentalExtension
         get() = DslObject(this).extensions.getByType(ExperimentalExtension::class.java)
 
-    var sourceSets: NamedDomainObjectContainer<KotlinSourceSet>
+    override var sourceSets: NamedDomainObjectContainer<KotlinSourceSet>
         @Suppress("UNCHECKED_CAST")
         get() = DslObject(this).extensions.getByName("sourceSets") as NamedDomainObjectContainer<KotlinSourceSet>
         internal set(value) {

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinTargetContainerWithNativeShortcuts.kt

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2010-2019 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.gradle.dsl
+
+import groovy.lang.Closure
+import org.gradle.util.ConfigureUtil
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation.Companion.MAIN_COMPILATION_NAME
+import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation.Companion.TEST_COMPILATION_NAME
+import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
+import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet.Companion.COMMON_MAIN_SOURCE_SET_NAME
+import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet.Companion.COMMON_TEST_SOURCE_SET_NAME
+import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSetContainer
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
+
+interface KotlinTargetContainerWithNativeShortcuts : KotlinTargetContainerWithPresetFunctions, KotlinSourceSetContainer {
+
+    private data class DefaultSourceSets(val main: KotlinSourceSet, val test: KotlinSourceSet)
+
+    private fun KotlinNativeTarget.defaultSourceSets(): DefaultSourceSets =
+        DefaultSourceSets(
+            compilations.getByName(MAIN_COMPILATION_NAME).defaultSourceSet,
+            compilations.getByName(TEST_COMPILATION_NAME).defaultSourceSet
+        )
+
+    private fun mostCommonSourceSets() = DefaultSourceSets(
+        sourceSets.getByName(COMMON_MAIN_SOURCE_SET_NAME),
+        sourceSets.getByName(COMMON_TEST_SOURCE_SET_NAME)
+    )
+
+    private fun List<KotlinNativeTarget>.defaultSourceSets(): List<DefaultSourceSets> = map { it.defaultSourceSets() }
+
+    private fun createIntermediateSourceSet(
+        name: String,
+        children: List<KotlinSourceSet>,
+        parent: KotlinSourceSet? = null
+    ) : KotlinSourceSet =
+        sourceSets.maybeCreate(name).apply {
+            parent?.let { dependsOn(parent) }
+            children.forEach {
+                it.dependsOn(this)
+            }
+        }
+
+    private fun createIntermediateSourceSets(
+        namePrefix: String,
+        children: List<DefaultSourceSets>,
+        parent: DefaultSourceSets? = null
+    ): DefaultSourceSets {
+        val main = createIntermediateSourceSet("${namePrefix}Main", children.map { it.main }, parent?.main)
+        val test = createIntermediateSourceSet("${namePrefix}Test", children.map { it.test }, parent?.test)
+        return DefaultSourceSets(main, test)
+    }
+
+    fun ios(
+        namePrefix: String = "ios",
+        configure: KotlinNativeTarget.() -> Unit = {}
+    ) {
+        val targets = listOf(
+            iosArm64("${namePrefix}Arm64"),
+            iosX64("${namePrefix}X64")
+        )
+        createIntermediateSourceSets(namePrefix, targets.defaultSourceSets(), mostCommonSourceSets())
+        targets.forEach { it.configure() }
+    }
+
+    fun ios() = ios("ios") { }
+    fun ios(namePrefix: String) = ios(namePrefix) { }
+    fun ios(namePrefix: String, configure: Closure<*>) = ios(namePrefix) { ConfigureUtil.configure(configure, this) }
+    fun ios(configure: Closure<*>) = ios { ConfigureUtil.configure(configure, this) }
+
+    fun tvos(
+        namePrefix: String = "tvos",
+        configure: KotlinNativeTarget.() -> Unit
+    ) {
+        val targets = listOf(
+            tvosArm64("${namePrefix}Arm64"),
+            tvosX64("${namePrefix}X64")
+        )
+        createIntermediateSourceSets(namePrefix, targets.defaultSourceSets(), mostCommonSourceSets())
+        targets.forEach { it.configure() }
+    }
+
+    fun tvos() = tvos("tvos") { }
+    fun tvos(namePrefix: String) = tvos(namePrefix) { }
+    fun tvos(namePrefix: String, configure: Closure<*>) = tvos(namePrefix) { ConfigureUtil.configure(configure, this) }
+    fun tvos(configure: Closure<*>) = tvos { ConfigureUtil.configure(configure, this) }
+
+    fun watchos(
+        namePrefix: String = "watchos",
+        configure: KotlinNativeTarget.() -> Unit = {}
+    ) {
+        val device32 = watchosArm32("${namePrefix}Arm32")
+        val device64 = watchosArm64("${namePrefix}Arm64")
+        val simulator = watchosX86("${namePrefix}X86")
+        val deviceTargets = listOf(device32, device64)
+
+        val deviceSourceSets = createIntermediateSourceSets(
+            "${namePrefix}Device",
+            deviceTargets.defaultSourceSets()
+        )
+
+        createIntermediateSourceSets(
+            namePrefix,
+            listOf(deviceSourceSets, simulator.defaultSourceSets()),
+            mostCommonSourceSets()
+        )
+
+        listOf(device32, device64, simulator).forEach { it.configure() }
+    }
+
+    fun watchos() = watchos("watchos") { }
+    fun watchos(namePrefix: String) = watchos(namePrefix) { }
+    fun watchos(namePrefix: String, configure: Closure<*>) = watchos(namePrefix) { ConfigureUtil.configure(configure, this) }
+    fun watchos(configure: Closure<*>) = watchos { ConfigureUtil.configure(configure, this) }
+}