Fix dynamic framework support and fix binary compatibility of SkikoUI… (#763)

* Fix dynamic framework support and fix binary compatibility of SkikoUIView

This change configures Kotlin Gradle
plugin to include a CInterop def file
(https://kotlinlang.org/docs/native-c-interop.html)
to fix linking a dynamic framework for iOS

Also helps with https://youtrack.jetbrains.com/issue/KT-60399
(at least in some cases). Internal discussion https://jetbrains.slack.com/archives/G017NLN12D8/p1689594898607469

* CR fix: use flatmap

skiko/build.gradle.kts

@@ -4,6 +4,7 @@ import org.gradle.crypto.checksum.Checksum
 import org.jetbrains.compose.internal.publishing.MavenCentralProperties
 import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
+import org.jetbrains.kotlin.gradle.tasks.CInteropProcess
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompileTool
 
 plugins {
@@ -427,6 +428,32 @@ kotlin {
     }
 }
 
+fun configureCinterop(
+    cinteropName: String,
+    os: OS,
+    arch: Arch,
+    target: KotlinNativeTarget,
+    targetString: String,
+    linkerOpts: List<String>,
+) {
+    val tasks = target.project.tasks
+    val taskNameSuffix = joinToTitleCamelCase(os.idWithSuffix(isIosSim = target.isIosSimArm64()), arch.id)
+    val writeCInteropDef = tasks.register("writeCInteropDef$taskNameSuffix", WriteCInteropDefFile::class.java) {
+        this.linkerOpts.set(linkerOpts)
+        outputFile.set(project.layout.buildDirectory.file("cinterop/$targetString/skiko.def"))
+    }
+    tasks.withType(CInteropProcess::class.java).configureEach {
+        if (konanTarget == target.konanTarget) {
+            dependsOn(writeCInteropDef)
+        }
+    }
+    target.compilations.getByName("main") {
+        cinterops.create(cinteropName).apply {
+            defFileProperty.set(writeCInteropDef.map { it.outputFile.get().asFile })
+        }
+    }
+}
+
 fun configureNativeTarget(os: OS, arch: Arch, target: KotlinNativeTarget) {
     if (!os.isCompatibleWithHost) return
 
@@ -444,24 +471,27 @@ fun configureNativeTarget(os: OS, arch: Arch, target: KotlinNativeTarget) {
 
     val skiaBinDir = "$skiaDir/out/${buildType.id}-$targetString"
     val linkerFlags = when (os) {
-        OS.MacOS -> mutableListOf("-linker-option", "-framework", "-linker-option", "Metal",
-            "-linker-option", "-framework", "-linker-option", "CoreGraphics",
-            "-linker-option", "-framework", "-linker-option", "CoreText",
-            "-linker-option", "-framework", "-linker-option", "CoreServices"
+        OS.MacOS -> mutableListOfLinkerOptions(
+            listOfFrameworks("Metal", "CoreGraphics", "CoreText", "CoreServices")
         )
-        OS.IOS -> mutableListOf("-linker-option", "-framework", "-linker-option", "Metal",
-            "-linker-option", "-framework", "-linker-option", "CoreGraphics",
-            "-linker-option", "-framework", "-linker-option", "UIKit",
-            "-linker-option", "-framework", "-linker-option", "CoreText")
-        OS.Linux -> mutableListOf(
-            "-linker-option", "-L/usr/lib/x86_64-linux-gnu",
-            "-linker-option", "-lfontconfig",
-            "-linker-option", "-lGL",
+        OS.IOS -> {
+            val iosFrameworks = listOfFrameworks("Metal", "CoreGraphics", "CoreText", "UIKit")
+            // list of linker options to be included into klib, which are needed for skiko consumers
+            // https://github.com/JetBrains/compose-multiplatform/issues/3178
+            // Important! Removing or renaming cinterop-uikit publication might cause compile error
+            // for projects depending on older Compose/Skiko transitively https://youtrack.jetbrains.com/issue/KT-60399
+            configureCinterop("uikit", os, arch, target, targetString, iosFrameworks)
+            mutableListOfLinkerOptions(iosFrameworks)
+        }
+        OS.Linux -> mutableListOfLinkerOptions(
+            "-L/usr/lib/x86_64-linux-gnu",
+            "-lfontconfig",
+            "-lGL",
             // TODO: an ugly hack, Linux linker searches only unresolved symbols.
-            "-linker-option", "$skiaBinDir/libsksg.a",
-            "-linker-option", "$skiaBinDir/libskshaper.a",
-            "-linker-option", "$skiaBinDir/libskunicode.a",
-            "-linker-option", "$skiaBinDir/libskia.a"
+            "$skiaBinDir/libsksg.a",
+            "$skiaBinDir/libskshaper.a",
+            "$skiaBinDir/libskunicode.a",
+            "$skiaBinDir/libskia.a"
         )
         else -> mutableListOf()
     }

skiko/buildSrc/src/main/kotlin/WriteCInteropDefFile.kt

+import org.gradle.api.DefaultTask
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.ListProperty
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+
+abstract class WriteCInteropDefFile : DefaultTask() {
+    @get:Input
+    abstract val linkerOpts: ListProperty<String>
+
+    @get:OutputFile
+    abstract val outputFile: RegularFileProperty
+
+    @TaskAction
+    fun run() {
+        val outputFile = outputFile.get().asFile
+        outputFile.parentFile.mkdirs()
+
+        outputFile.bufferedWriter().use { writer ->
+            val linkerOpts = linkerOpts.get()
+            if (linkerOpts.isNotEmpty()) {
+                writer.appendLine("linkerOpts=${linkerOpts.joinToString(" ")}")
+            }
+        }
+    }
+}
\ No newline at end of file

skiko/buildSrc/src/main/kotlin/utils.kt

@@ -6,6 +6,7 @@ import org.gradle.api.tasks.TaskContainer
 import org.gradle.api.tasks.TaskProvider
 import org.gradle.kotlin.dsl.register
 import java.util.*
+import kotlin.collections.ArrayList
 
 // Utils, that are not needed in scripts can be placed to internal/utils
 
@@ -43,3 +44,15 @@ fun Task.projectDirs(vararg relativePaths: String): List<Directory> {
     val projectDir = project.layout.projectDirectory
     return relativePaths.map { path -> projectDir.dir(path) }
 }
+
+fun listOfFrameworks(vararg frameworks: String): List<String> =
+    frameworks.toList().addElementBeforeEach("-framework")
+
+fun mutableListOfLinkerOptions(options: Collection<String>): MutableList<String> =
+    options.addElementBeforeEach("-linker-option")
+
+fun mutableListOfLinkerOptions(vararg options: String): MutableList<String> =
+    mutableListOfLinkerOptions(options.toList())
+
+private fun <T> Collection<T>.addElementBeforeEach(element: T): MutableList<T> =
+    flatMapTo(ArrayList(size * 2)) { listOf(element, it) }

skiko/src/iosMain/kotlin/org/jetbrains/skiko/SkikoUIView.kt

@@ -11,6 +11,10 @@ import platform.darwin.NSInteger
 import kotlin.math.max
 import kotlin.math.min
 
+/*
+ TODO: remove org.jetbrains.skiko.objc.UIViewExtensionProtocol after Kotlin 1.8.20
+ https://youtrack.jetbrains.com/issue/KT-40426
+*/
 @Suppress("CONFLICTING_OVERLOADS")
 @ExportObjCClass
 class SkikoUIView : UIView, UIKeyInputProtocol, UITextInputProtocol {
@@ -30,11 +34,20 @@ class SkikoUIView : UIView, UIKeyInputProtocol, UITextInputProtocol {
     private var _inputDelegate: UITextInputDelegateProtocol? = null
     private var _currentTextMenuActions: TextActions? = null
 
+    // merging two constructors might cause a binary incompatibility, which will result in a unclear linking error,
+    // if a project using newer compose depends on an older compose transitively
+    // https://youtrack.jetbrains.com/issue/KT-60399
+    constructor(
+        skiaLayer: SkiaLayer,
+        frame: CValue<CGRect> = CGRectNull.readValue(),
+        pointInside: (Point, UIEvent?) -> Boolean = {_,_-> true }
+    ) : this(skiaLayer, frame, pointInside, skikoUITextInputTrains = object : SkikoUITextInputTraits {})
+
     constructor(
         skiaLayer: SkiaLayer,
         frame: CValue<CGRect> = CGRectNull.readValue(),
         pointInside: (Point, UIEvent?) -> Boolean = {_,_-> true },
-        skikoUITextInputTrains: SkikoUITextInputTraits = object : SkikoUITextInputTraits {},
+        skikoUITextInputTrains: SkikoUITextInputTraits
     ) : super(frame) {
         this.skiaLayer = skiaLayer
         _pointInside = pointInside