Move transitiveClosure into :commonizer-api

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/sources/DefaultKotlinSourceSet.kt

@@ -11,6 +11,7 @@ import org.gradle.api.Project
 import org.gradle.api.file.SourceDirectorySet
 import org.gradle.util.ConfigureUtil
 import org.jetbrains.kotlin.build.DEFAULT_KOTLIN_SOURCE_FILES_EXTENSIONS
+import org.jetbrains.kotlin.commonizer.util.transitiveClosure
 import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
 import org.jetbrains.kotlin.gradle.plugin.KotlinDependencyHandler
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
@@ -246,7 +247,7 @@ internal operator fun KotlinSourceSet.plus(sourceSets: Set<KotlinSourceSet>): Se
 }
 
 internal fun KotlinSourceSet.resolveAllDependsOnSourceSets(): Set<KotlinSourceSet> {
-    return transitiveClosure { dependsOn }
+    return transitiveClosure(this) { dependsOn }
 }
 
 internal fun Iterable<KotlinSourceSet>.resolveAllDependsOnSourceSets(): Set<KotlinSourceSet> {
@@ -254,5 +255,5 @@ internal fun Iterable<KotlinSourceSet>.resolveAllDependsOnSourceSets(): Set<Kotl
 }
 
 internal fun KotlinMultiplatformExtension.resolveAllSourceSetsDependingOn(sourceSet: KotlinSourceSet): Set<KotlinSourceSet> {
-    return sourceSet.transitiveClosure { sourceSets.filter { otherSourceSet -> this in otherSourceSet.dependsOn } }
+    return transitiveClosure(sourceSet) { sourceSets.filter { otherSourceSet -> this in otherSourceSet.dependsOn } }
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerTask.kt

@@ -24,7 +24,7 @@ import org.jetbrains.kotlin.gradle.plugin.mpp.kotlinSourceSetsIncludingDefault
 import org.jetbrains.kotlin.gradle.plugin.sources.resolveAllDependsOnSourceSets
 import org.jetbrains.kotlin.gradle.targets.native.internal.CInteropCommonizerTask.CInteropGist
 import org.jetbrains.kotlin.gradle.tasks.CInteropProcess
-import org.jetbrains.kotlin.gradle.utils.transitiveClosure
+import org.jetbrains.kotlin.commonizer.util.transitiveClosure
 import org.jetbrains.kotlin.gradle.utils.fileProvider
 import org.jetbrains.kotlin.konan.target.KonanTarget
 import java.io.File
@@ -211,7 +211,7 @@ private operator fun CommonizerTarget.contains(other: CommonizerTarget): Boolean
 }
 
 private fun SharedCommonizerTarget.withAllTransitiveTargets(): Set<CommonizerTarget> {
-    return setOf(this) + this.transitiveClosure<CommonizerTarget> { if (this is SharedCommonizerTarget) this.targets else emptySet() }
+    return setOf(this) + transitiveClosure<CommonizerTarget>(this) { if (this is SharedCommonizerTarget) this.targets else emptySet() }
 }
 
 private fun Project.getDependingNativeCompilations(compilation: KotlinSharedNativeCompilation): Set<KotlinNativeCompilation> {

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/utils/transitiveClosure.kt

@@ -1,39 +0,0 @@
-/*
- * 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.gradle.utils
-
-/**
- * General purpose implementation of a transitive closure
- * - Recursion free
- * - Predictable amount of allocations
- * - Handles loops and self references gracefully
- * @param edges: Producer function from one node to all its children. This implementation can handle loops and self references gracefully.
- * @return Note: No guarantees given about the order ot this [Set]
- */
-internal inline fun <reified T> T.transitiveClosure(edges: T.() -> Iterable<T>): Set<T> {
-    // Fast path when initial edges are empty
-    val initialEdges = edges()
-    if (initialEdges is Collection && initialEdges.isEmpty()) return emptySet()
-
-    val queue = deque<T>()
-    val results = mutableSetOf<T>()
-    queue.addAll(initialEdges)
-    while (queue.isNotEmpty()) {
-        // ArrayDeque implementation will optimize this call to 'removeFirst'
-        val resolved = queue.removeAt(0)
-        if (resolved != this && results.add(resolved)) {
-            queue.addAll(resolved.edges())
-        }
-    }
-
-    return results.toSet()
-}
-
-@OptIn(ExperimentalStdlibApi::class)
-private inline fun <reified T> deque(): MutableList<T> {
-    return if (KotlinVersion.CURRENT.isAtLeast(1, 4)) ArrayDeque()
-    else mutableListOf()
-}

libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/utils/TransitiveClosureTest.kt

@@ -1,60 +0,0 @@
-/*
- * 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.gradle.utils
-
-import kotlin.test.Test
-import kotlin.test.assertEquals
-
-class TransitiveClosureTest {
-    private class Node(val value: String, val children: MutableList<Node> = mutableListOf()) {
-
-        override fun toString(): String {
-            return value
-        }
-
-        override fun equals(other: Any?): Boolean {
-            if (other !is Node) return false
-            return other.value == value
-        }
-
-        override fun hashCode(): Int {
-            return value.hashCode()
-        }
-    }
-
-    private fun Node.transitiveClosure() = transitiveClosure { children }
-
-    @Test
-    fun `transitiveClosure does not include root node`() {
-        val closure = Node("a", mutableListOf(Node("b"), Node("c"))).transitiveClosure()
-        assertEquals(setOf(Node("b"), Node("c")), closure, "Expected transitiveClosure to not include root node")
-    }
-
-    @Test
-    fun `transitiveClosure handles loop and self references`() {
-        val nodeA = Node("a")
-        val nodeB = Node("b")
-        val nodeC = Node("c")
-        val nodeD = Node("d")
-
-        // a -> b -> c -> d
-        nodeA.children.add(nodeB)
-        nodeB.children.add(nodeC)
-        nodeC.children.add(nodeD)
-
-        // add self reference to b
-        nodeB.children.add(nodeB)
-
-        // add loop from c -> a
-        nodeC.children.add(nodeA)
-
-        val closure = nodeA.transitiveClosure()
-        assertEquals(
-            setOf(nodeB, nodeC, nodeD), closure,
-            "Expected transitiveClosure to be robust against loops and self references"
-        )
-    }
-}