KSPの話がしたい！

Transcript

1. KSPの話がしたい
 今 KMPがホットだけど
 2024/7/19
 集まれKotlin好き！Kotlin愛好会 vol. 53
 Kota Kimura

2. 話すこと
 - Overview
 - 仕組み
 - コード例
 - With KMP 
 - KSP2

3. kk__777 （ けーけー） ⽊村 洸太 株式会社はてな - 2023年8⽉〜 - マンガアプリ GigaViewer for Apps Android（2020〜） Qiita https://qiita.com/kk__777
4. KSP Overview

5. Compiler Plugin

6. annotation class SampleAnnotation @SampleAnnotation class Greeting { private val platform = getPlatform() fun greet(): String = "Hello, ${platform.name}!" }
7. class TestProcessor( private val codeGenerator: CodeGenerator, private val kspLogger: KSPLogger, ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { resolver .getSymbolsWithAnnotation(SampleAnnotation::class.qualifiedName!!) .filterIsInstance<KSClassDeclaration>() .forEach { ksClassDeclaration -> kspLogger.logging("Found class : ${ksClassDeclaration.qualifiedName}") ksClassDeclaration.getAllProperties().forEach { ksPropertyDeclaration -> kspLogger.logging("Found class property: ${ksPropertyDeclaration.qualifiedName}") } ksClassDeclaration.getAllFunctions().forEach { ksFunctionDeclaration -> kspLogger.logging("Found class function: ${ksFunctionDeclaration.qualifiedName}") } /// ... コード生成ロジック } } } i: [ksp] Found class : Greeting i: [ksp] Found class property: Greeting.platform i: [ksp] Found class function: Greeting.greet
8. annotation class SampleAnnotation @SampleAnnotation class Greeting { private val platform = getPlatform() fun greet(): String = "Hello, ${platform.name}!" }
9. できないこと

10. - コードの改変はできない
 
 - 式レベルにアクセスできない

11. 仕組み

12. - Processor
 - Resolver
 - Symbol

13. Processor

14. class TestProcessor( private val codeGenerator: CodeGenerator, private val kspLogger: KSPLogger, ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { resolver .getSymbolsWithAnnotation(SampleAnnotation::class.qualifiedName!!) .filterIsInstance<KSClassDeclaration>() .forEach { ksClassDeclaration -> kspLogger.logging("Found class : ${ksClassDeclaration.qualifiedName}") ksClassDeclaration.getAllProperties().forEach { ksPropertyDeclaration -> kspLogger.logging("Found class property: ${ksPropertyDeclaration.qualifiedName}") } ksClassDeclaration.getAllFunctions().forEach { ksFunctionDeclaration -> kspLogger.logging("Found class function: ${ksFunctionDeclaration.qualifiedName}") } /// ... コード生成ロジック } } }
15. class TestProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ):SymbolProcessor = TestProcessor(environment.codeGenerator, environment.logger) }
16. plugins { kotlin("jvm") } ... dependencies { implementation(kotlin("stdlib")) implementation("com.squareup:javapoet:1.12.1") implementation("com.google.devtools.ksp:symbol-processing-api:$kspVersion") } dependencies { implementation(kotlin("stdlib")) implementation(project(":test-processor")) ksp(project(":test-processor")) } Processor側 Processorを 受け入れる側
17. Resolver

18. class TestProcessor( private val codeGenerator: CodeGenerator, private val kspLogger: KSPLogger, ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { resolver .getSymbolsWithAnnotation(SampleAnnotation::class.qualifiedName!!) .filterIsInstance<KSClassDeclaration>() .forEach { ksClassDeclaration -> kspLogger.logging("Found class : ${ksClassDeclaration.qualifiedName}") ksClassDeclaration.getAllProperties().forEach { ksPropertyDeclaration -> kspLogger.logging("Found class property: ${ksPropertyDeclaration.qualifiedName}") } ksClassDeclaration.getAllFunctions().forEach { ksFunctionDeclaration -> kspLogger.logging("Found class function: ${ksFunctionDeclaration.qualifiedName}") } /// ... コード生成ロジック } } }
19. • Resolver.getAllFiles
 
 • Resolver.getSymbolsWithAnnotation
 
 • Resolver.getClassDeclarationByName
 
 • Resolver.getDeclarationsFromPackage
 etc
20. Symbol

21. interface Greeting { val arg1: String val arg2: Map<String, List<*>> }
22. KSFile packageName: KSName fileName: String annotations: List<KSAnnotation> (File annotations) declarations: List<KSDeclaration> // class, interface, object KSClassDeclaration simpleName: KSName qualifiedName: KSName containingFile: String typeParameters: KSTypeParameter parentDeclaration: KSDeclaration classKind: ClassKind primaryConstructor: KSFunctionDeclaration superTypes: List<KSTypeReference> // contains inner classes, member functions, properties, etc. declarations: List<KSDeclaration> KSFunctionDeclaration // top level function simpleName: KSName qualifiedName: KSName containingFile: String typeParameters: KSTypeParameter parentDeclaration: KSDeclaration functionKind: FunctionKind extensionReceiver: KSTypeReference? returnType: KSTypeReference parameters: List<KSValueParameter> // contains local classes, local functions, local variables, etc. declarations: List<KSDeclaration> KSPropertyDeclaration // global variable simpleName: KSName qualifiedName: KSName containingFile: String typeParameters: KSTypeParameter parentDeclaration: KSDeclaration extensionReceiver: KSTypeReference? type: KSTypeReference getter: KSPropertyGetter returnType: KSTypeReference setter: KSPropertySetter parameter: KSValueParameter
23. コード生成

24. class TestProcessor( private val codeGenerator: CodeGenerator, private val kspLogger: KSPLogger, ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { resolver .getSymbolsWithAnnotation(SampleAnnotation::class.qualifiedName!!) .filterIsInstance<KSClassDeclaration>() .forEach { ksClassDeclaration -> kspLogger.logging("Found class : ${ksClassDeclaration.qualifiedName}") ksClassDeclaration.getAllProperties().forEach { ksPropertyDeclaration -> kspLogger.logging("Found class property: ${ksPropertyDeclaration.qualifiedName}") } ksClassDeclaration.getAllFunctions().forEach { ksFunctionDeclaration -> kspLogger.logging("Found class function: ${ksFunctionDeclaration.qualifiedName}") } /// ... コード生成ロジック } } }
25. KotlinPoet
 https://square.github.io/kotlinpoet/ Kotlinのコード生成をBuilderパターンで若干楽に 記述できるライブラリ
26. class Greeter(val name: String) { fun greet() { println("""Hello, $name""") } } fun main(vararg args: String) { Greeter(args[0]).greet() } val greeterClass = ClassName("", "Greeter") val file = FileSpec.builder("", "HelloWorld") .addType( TypeSpec.classBuilder("Greeter") .primaryConstructor( FunSpec.constructorBuilder() .addParameter("name", String::class) .build() ) .addProperty( PropertySpec.builder("name", String::class) .initializer("name") .build() ) .addFunction( FunSpec.builder("greet") .addStatement("println(%P)", "Hello, \$name") .build() ) .build() ) .addFunction( FunSpec.builder("main") .addParameter("args", String::class, VARARG) .addStatement("%T(args[0]).greet()", greeterClass) .build() ) .build() file.writeTo(System.out)
27. 基本 は 取得したシンボルの情報を KotlinPoet に食わせて 欲しいファイルを生成する

28. たとえば

29. interface Greeting { fun greet(): String } @Module @InstallIn(SingletonComponent::class) abstract class Binder { @BindsOptinalOf abstract fun binds(): Greeting } 対応
 変数
30. @Target(AnnotationTarget.CLASS) annotation class BindsOptionalHiltModule( val components: Array<InstallInComponent> ) @BindsOptionalHiltModule([InstallInComponent.SingletonComponent]) interface Greeting { fun greet(): String }
31. override fun process(resolver: Resolver): List<KSAnnotated> { resolver .getSymbolsWithAnnotation(BindsOptionalHiltModule::class.qualifiedName!!) .filterIsInstance<KSClassDeclaration>() .forEach { ksClassDeclaration -> val fileSpec = FileSpec.builder( ksClassDeclaration.packageName.getQualifier(), ksClassDeclaration.simpleName.getShortName() + "Binder", ) ksClassDeclaration.accept(BindsOptionalHiltModuleVisitor(), fileSpec) fileSpec.build().writeTo(codeGenerator, Dependencies(false, ksClassDeclaration.containingFile!!)) } ...
32. inner class BindsOptionalHiltModuleVisitor : KSDefaultVisitor<FileSpec.Builder, Unit>() { override fun visitClassDeclaration(classDeclaration: KSClassDeclaration, data: FileSpec.Builder) { check(classDeclaration.classKind == ClassKind.INTERFACE) { "BindsOptionalHiltModule must annotate interface" } val typeSpec = TypeSpec .classBuilder(classDeclaration.simpleName.asString() + "Binder") .addModifiers(KModifier.ABSTRACT) .addAnnotations(listOf(AnnotationSpec.builder(Module).build())) val installInAnnotationSpecBuilder = AnnotationSpec.builder(InstallIn) // InstallIn Componentの生成 classDeclaration.annotations.forEach { it.arguments.forEach { arg -> val components = arg.value as? List<*> components?.forEach { componentEnum -> val ksType = componentEnum as? KSType ?: return val componentClassName = InstallInComponent.createComponentClassName(ksType) installInAnnotationSpecBuilder .addMember("%T::class", componentClassName) } } } // abstract fun の バインド関数作成 val bindsFunSpec = FunSpec .builder("bindOptional" + classDeclaration.simpleName.asString()) .addModifiers(KModifier.ABSTRACT) .addAnnotation(AnnotationSpec.builder(BindsOptionalOf).build()) .returns(classDeclaration.toClassName()) .build() data.addType( typeSpec .addAnnotation(installInAnnotationSpecBuilder.build()) .addFunction(bindsFunSpec) .build(), ) } … 注釈はInterfaceに限る
 @Module @InstallIn(...) public abstract class GreetingBinder SingletonComponent::class
 @BindsOptionalOf public abstract fun bindOptionalGreeting(): Greeting
33. @Module @InstallIn(SingletonComponent::class) public abstract class GreetingBinder { @BindsOptionalOf public abstract fun bindOptionalGreeting(): Greeting }
34. なぜKSPか
 CompilerPlugin比較
 https://kotlinlang.org/docs/ksp-why-ksp.html
35. Kapt
 - Java のエコシステムに紐づけられるので、 他のター ゲット で 予期せぬエラーが出やすい - パフォーマンス；kaptは8.67秒、KSP実装は1.15秒
36. kotlinc compiler plugin
 - kotlincは compiler のほとんど全てにアクセス可能 - 実装詳細を知っている必要がある - 特定のCompilerバージョンと結合が強い
37. KSP
 - compiler の 変更を 隠蔽するようにデザインされている - KSPのAPIを通じてのみ Compiler にアクセス - 「できないこと」 とトレードオフに シンプルなmeta programming が可能
38. With KMP

39. Processor は JVMターゲット 
 plugins { alias(libs.plugins.kotlinMultiplatform) } kotlin { jvm() sourceSets { jvmMain.dependencies { implementation(libs.ksp.poet) implementation(libs.ksp.poet.extension) implementation(libs.ksp.symbol.processing.api) implementation(projects.annotations) } } }
40. Processor を受け入れる側は.. plugins { alias(libs.plugins.kotlinMultiplatform) alias(libs.plugins.androidLibrary) alias(libs.plugins.ksp) } kotlin { wasmJs { ... } androidTarget { ... } iosTargets.forEach { ... } jvm { ... } sourceSets { commonMain.dependencies { // put your Multiplatform dependencies here implementation(projects.annotations) } } } dependencies { add("kspCommonMainMetadata", projects.testProcessor) add("kspJvm", projects.testProcessor) add("kspAndroid", projects.testProcessor) add("kspWasmJs", projects.testProcessor) add("kspIosX64", projects.testProcessor) add("kspIosArm64", projects.testProcessor) add("kspIosSimulatorArm64", projects.testProcessor) }
41. AndroidMain iOS JVM WasmJS - Greeting は CommonMainの ソースから生成 - *Platformはプラットフォームごと のソースから生成
42. ただし、、

43. • CommonMainにコード生成ができな い#567 
 • KotlinNative は 根っこのターゲット の ソースセットで生成される #929
 今の所この辺が 制約になっている https://qiita.com/kk__777/items/f6a95932990040586ea2
44. 👈 ソース側 buildフォルダ 👉
45. KSP2

46. https://github.com/google/ksp/blob/main/docs/ksp2.md
47. KSPはCompilerPluginといって きましたが

48. KSP2から CompilerPluginでは なくなるそうです

49. KSP2 is a new implementation of the KSP API. Unlike KSP 1.x, it is no longer a compiler plugin and is built on the same set of Kotlin compiler APIs shared with IntelliJ IDEA, Android Lint, etc. Compared to the compiler-plugin approach, this allows a finer control of the program life cycle, simplifies KSP’s implementation and is more efficient.
 https://github.com/google/ksp/blob/main/docs/ksp2.md
 Compiler Plugin ではなく、AndroidLintやIntellJ IDEA で共有されてる Kotlin compiler APIs 上で ビルドされる とのこと

50. • ライフサイクルの細かな制御
 
 • 実装を簡素化 & 効率化
 KSPの内部的には
51. • エントリーポイントの作成が容易になっ た 
 使う側の利点としては
52. たとえば main関数から呼び出してみるとこんな感じ fun main() { // Step 1: Load processors val classpath = listOf("test-processor/build/classes/kotlin/main") val processorClassloader = URLClassLoader(classpath.map { File(it).toURI().toURL() }.toTypedArray()) val processorProviders = ServiceLoader.load( processorClassloader.loadClass("com.google.devtools.ksp.processing.SymbolProcessorProvider"), processorClassloader ).toList() as List<SymbolProcessorProvider> // Step 2: Implement or use KSPLogger val logger = KspGradleLogger(KspGradleLogger.LOGGING_LEVEL_INFO) // Step 3: Fill KSPConfig val kspConfig = KSPJvmConfig.Builder().apply { moduleName = "mainsrc" sourceRoots = listOf(File("mainsrc/src/main/kotlin")) kotlinOutputDir = File("mainsrc/build/generated/ksp/main/kotlin") javaOutputDir = File("mainsrc/build/generated/ksp/main/java") jvmTarget = "1.8" projectBaseDir = File(".") outputBaseDir = File("mainsrc/build/generated/ksp/main") cachesDir = File("mainsrc/build/generated/ksp/main/caches") classOutputDir = File("mainsrc/build/generated/ksp/main/classes") resourceOutputDir = File("mainsrc/build/generated/ksp/main/resources") apiVersion = "2.0.0-1.0.23" languageVersion = "2.0" }.build() // Step 4: Run KotlinSymbolProcessing val exitCode = KotlinSymbolProcessing(kspConfig, processorProviders, logger).execute() println("KSP finished with exit code: $exitCode") } https://qiita.com/kk__777/items/fd3af8eb11ade9677a4e
53. - 他にもAPI変更点がある 詳しくは👇 https://github.com/google/ksp/blob/main/docs/ksp2api.md
 - KSPからの移行は 2.0 のうちは 容易 2.1以降は KSP を 追従させる よりは KSP2を使ってね といったこ とが書かれている https://github.com/google/ksp/blob/main/docs/ksp2.md#ksp1-deprec ation-schedule

54. KSPつかっていきましょ