Implement 'CommonizerTarget.fileName' and limit fileName length

^KT-46856 Fixed

native/commonizer-api/src/org/jetbrains/kotlin/commonizer/TargetLibrariesLayout.kt

@@ -8,6 +8,8 @@ package org.jetbrains.kotlin.commonizer
 import org.jetbrains.kotlin.konan.library.KONAN_DISTRIBUTION_COMMON_LIBS_DIR
 import org.jetbrains.kotlin.konan.library.KONAN_DISTRIBUTION_PLATFORM_LIBS_DIR
 import java.io.File
+import java.security.MessageDigest
+import java.util.*
 
 
 public fun interface CommonizerOutputLayout {
@@ -24,7 +26,27 @@ public object NativeDistributionCommonizerOutputLayout : CommonizerOutputLayout
 }
 
 public object HierarchicalCommonizerOutputLayout : CommonizerOutputLayout {
+    internal const val maxFileNameLength = 150
+
     override fun getTargetDirectory(root: File, target: CommonizerTarget): File {
-        return root.resolve(target.identityString)
+        return root.resolve(target.fileName)
     }
+
+    public val CommonizerTarget.fileName: String
+        get() {
+            val identityString = identityString
+            return if (identityString.length <= maxFileNameLength) identityString
+            else {
+                val hashSuffix = "[--$identityStringHash]"
+                return identityString.take(maxFileNameLength - hashSuffix.length) + hashSuffix
+            }
+        }
+
+    private val CommonizerTarget.identityStringHash: String
+        get() {
+            val sha = MessageDigest.getInstance("SHA-1")
+            val base64 = Base64.getUrlEncoder()
+            return base64.encode(sha.digest(identityString.encodeToByteArray())).decodeToString()
+        }
 }
+

native/commonizer-api/test/org/jetbrains/kotlin/commonizer/CommonizerTargetFileNameTest.kt

@@ -0,0 +1,67 @@
+/*
+ * 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.commonizer
+
+import org.jetbrains.kotlin.commonizer.HierarchicalCommonizerOutputLayout.fileName
+import org.jetbrains.kotlin.commonizer.HierarchicalCommonizerOutputLayout.maxFileNameLength
+import org.junit.Rule
+import org.junit.rules.TemporaryFolder
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class CommonizerTargetFileNameTest {
+
+    private val longCommonizerTarget = parseCommonizerTarget(
+        buildString {
+            append("(")
+            append(
+                sequence {
+                    var i = 0
+                    while (true) {
+                        yield(i.toString())
+                        i++
+                    }
+                }.take(maxFileNameLength).joinToString(", ")
+            )
+            append(")")
+        }
+    )
+
+    @get:Rule
+    val temporaryFolder = TemporaryFolder()
+
+    @Test
+    fun `small targets will use identityString`() {
+        val target = parseCommonizerTarget("((a, b), c)")
+        assertEquals(target.identityString, target.fileName)
+    }
+
+    @OptIn(ExperimentalStdlibApi::class)
+    @Test
+    fun `longCommonizerTarget respect maximum fileName length`() {
+        assertTrue(
+            longCommonizerTarget.identityString.length > maxFileNameLength,
+            "Expected test target's identityString to exceed maxFileNameLength"
+        )
+
+        assertEquals(
+            longCommonizerTarget.fileName.length, maxFileNameLength,
+            "Expected test target's fileName to be exactly match the maximum"
+        )
+    }
+
+    @Test
+    fun `longCommonizerTarget fileName can create new file`() {
+        val longCommonizerTargetFile = temporaryFolder.root.resolve(longCommonizerTarget.fileName)
+        assertTrue(longCommonizerTargetFile.createNewFile(), "Expected being able to create file $longCommonizerTargetFile")
+        longCommonizerTargetFile.writeText(longCommonizerTarget.identityString)
+        assertEquals(
+            longCommonizerTarget, parseCommonizerTarget(longCommonizerTargetFile.readText()),
+            "Expected being able to read and write to $longCommonizerTargetFile"
+        )
+    }
+}