Kotlin Symbol Processing (KSP) を使ったコード生成 / DroidKaigi 2021

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1. Kotlin Symbol Processing (KSP) を使ったコード生成 Kenji Abe
2. About me • Kenji Abe • Google Developers Expert for Android, Kotlin • AndroidDagashi • DeNA Co., Ltd. • @STAR_ZERO
3. Kotlin Symbol Processing (KSP) • https://github.com/google/ksp • Kotlinの軽量コンパイラプラグインを開発できるツール • KAPTに似た機能を提供できる（コード生成） • KAPTに比べて高速 • Kotlinのコードを直接解析できる • Kotlin Multiplatformのサポート
4. 基本構成
9. dependencies { implementation("com.google.devtools.ksp:symbol-processing-api:1.5.30-1.0.0") }
11. com.example.processor.HelloWorldProcessorProvider
12. plugins { id("com.google.devtools.ksp") version "1.5.30-1.0.0" // ... } dependencies { ksp(project(":processor")) }
13. 実装詳細
14. SymbolProcessorProvider
15. SymbolProcessorProvider • エントリーポイント • ServiceLoaderによって生成される (META-INF/services) • createメソッドでSymbolProcessorを生成して返す必要がある • createメソッドの引数から処理に必要なオブジェクトを受け取れる ◦ CodeGenerator ◦ Logger ◦ Option
16. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } }
17. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } }
18. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } }
19. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } }
20. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } }
21. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } } // build.gradle.kts ksp { arg("key", "value") }
22. class HelloWorldProcessorProvider : SymbolProcessorProvider { override fun create( environment: SymbolProcessorEnvironment ): SymbolProcessor { return HelloWorldProcessor( environment.codeGenerator, environment.options, environment.logger ) } } logger.logging("...") logger.info("...") logger.warn("...") logger.error("...") $ ./gradlew build --debug or $ ./gradlew build --info
23. SymbolProcessor
24. SymbolProcessor • SymbolProcessorProviderで生成される • processメソッドでコード解析やコード生成を行う • finish、onErrorメソッドもある
25. class HelloWorldProcessor( private val codeGenerator: CodeGenerator, private val options: Map<String, String>, private val logger: KSPLogger ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { // } }
26. class HelloWorldProcessor( private val codeGenerator: CodeGenerator, private val options: Map<String, String>, private val logger: KSPLogger ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { // } }
27. class HelloWorldProcessor( private val codeGenerator: CodeGenerator, private val options: Map<String, String>, private val logger: KSPLogger ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { // } }
28. class HelloWorldProcessor( private val codeGenerator: CodeGenerator, private val options: Map<String, String>, private val logger: KSPLogger ) : SymbolProcessor { override fun process(resolver: Resolver): List<KSAnnotated> { // } }
29. コード解析
30. https://github.com/google/ksp/blob/main/docs/ksp-additional-details.md
31. override fun process(resolver: Resolver): List<KSAnnotated> { val files = resolver.getAllFiles() val newFiles = resolver.getNewFiles() val symbols = resolver.getSymbolsWithAnnotation("com.example.Factory") val ksClass = resolver.getClassDeclarationByName("com.example.Hoge") // ... }
32. override fun process(resolver: Resolver): List<KSAnnotated> { val files = resolver.getAllFiles() val newFiles = resolver.getNewFiles() val symbols = resolver.getSymbolsWithAnnotation("com.example.Factory") val ksClass = resolver.getClassDeclarationByName("com.example.Hoge") // ... }
33. override fun process(resolver: Resolver): List<KSAnnotated> { val files = resolver.getAllFiles() val newFiles = resolver.getNewFiles() val symbols = resolver.getSymbolsWithAnnotation("com.example.Factory") val ksClass = resolver.getClassDeclarationByName("com.example.Hoge") // ... }
34. override fun process(resolver: Resolver): List<KSAnnotated> { val symbols = resolver.getSymbolsWithAnnotation("com.example.Factory") symbols.forEach { when (it) { is KSClassDeclaration -> { } is KSFunctionDeclaration -> { } is KSPropertyDeclaration -> { } } } // ... }
35. https://github.com/google/ksp/blob/main/README.md#how-ksp-looks-at-source-files
36. CodeGenerator
37. override fun process(resolver: Resolver): List<KSAnnotated> { val file = codeGenerator.createNewFile( Dependencies(false), "com.example.generated", "Hello" ) val code = """ ... """.trimIndent() file.write(code.toByteArray()) file.close() // ... }
38. override fun process(resolver: Resolver): List<KSAnnotated> { val file = codeGenerator.createNewFile( Dependencies(false), "com.example.generated", "Hello" ) val code = """ ... """.trimIndent() file.write(code.toByteArray()) file.close() // ... }
39. override fun process(resolver: Resolver): List<KSAnnotated> { val file = codeGenerator.createNewFile( Dependencies(false), "com.example.generated", "Hello" ) val code = """ ... """.trimIndent() file.write(code.toByteArray()) file.close() // ... }
40. override fun process(resolver: Resolver): List<KSAnnotated> { val file = codeGenerator.createNewFile( Dependencies(false), "com.example.generated", "Hello" ) val code = """ ... """.trimIndent() file.write(code.toByteArray()) file.close() // ... }
41. val file = codeGenerator.createNewFile( Dependencies(false), "hoge/foo", "plain", "txt" )
42. Multiple round processing
43. // Hoge.kt @Factory class Hoge // Foo.kt @Factory class Foo // etc... // SymbolProcessor#process resolver.getSymbolsWithAnnotation("...") // =>
44. // Hoge.kt @Factory class Hoge // Foo.kt @Factory class Foo // etc... // SymbolProcessor#process resolver.getSymbolsWithAnnotation("...") // => [Hoge, Foo]
45. // Hoge.kt @Factory class Hoge // Foo.kt @Factory class Foo // etc... // SymbolProcessor#process resolver.getSymbolsWithAnnotation("...") // => [Hoge, Foo] // HogeFactory.kt class HogeFactory // FooFactory.kt class FooFactory コード生成
46. // Hoge.kt @Factory class Hoge // Foo.kt @Factory class Foo // etc... // SymbolProcessor#process resolver.getSymbolsWithAnnotation("...") // => // HogeFactory.kt class HogeFactory // FooFactory.kt class FooFactory コード生成
47. // Hoge.kt @Factory class Hoge // Foo.kt @Factory class Foo // etc... // SymbolProcessor#process resolver.getSymbolsWithAnnotation("...") // => [] // HogeFactory.kt class HogeFactory // FooFactory.kt class FooFactory コード生成
48. // Hoge.kt @Factory class Hoge // Foo.kt @Factory class Foo // etc... // SymbolProcessor#process resolver.getSymbolsWithAnnotation("...") // => [] // HogeFactory.kt class HogeFactory // FooFactory.kt class FooFactory コード生成 Finish
49. @Factory class Hoge(hello: Hello) HelloProcessor class Hello FactoryProcessor
50. @Factory class Hoge(hello: Hello) HelloProcessor FactoryProcessor Hoge => Hello🤔
51. override fun process(resolver: Resolver): List<KSAnnotated> { val symbols = resolver.getSymbolsWithAnnotation("...") val result = symbols.filter { !it.validate() }.toList() symbols.filter { it.validate() }.forEach { symbol -> // コード生成 } return result }
52. override fun process(resolver: Resolver): List<KSAnnotated> { val symbols = resolver.getSymbolsWithAnnotation("...") val result = symbols.filter { !it.validate() }.toList() symbols.filter { it.validate() }.forEach { symbol -> // コード生成 } return result }
53. override fun process(resolver: Resolver): List<KSAnnotated> { val symbols = resolver.getSymbolsWithAnnotation("...") val result = symbols.filter { !it.validate() }.toList() symbols.filter { it.validate() }.forEach { symbol -> // コード生成 } return result }
54. override fun process(resolver: Resolver): List<KSAnnotated> { val symbols = resolver.getSymbolsWithAnnotation("...") val result = symbols.filter { !it.validate() }.toList() symbols.filter { it.validate() }.forEach { symbol -> // コード生成 } return result }
55. Resolver • getAllFiles ◦ 全てのラウンドでの処理対象となったファイル • getNewFiles ◦ ラウンドごとに処理対象となっているファイル • getSymbolsWithAnnotation ◦ ラウンドごとに処理対象となっているものから、該当の Annotationがあるもの • getClassDeclarationByName ◦ クラスパスから指定したクラス名を探す
56. Incremental processing
57. Hoge.kt Foo.kt SymbolProcessor HogeFactory.kt FooFactory.kt Clean Build
58. Hoge.kt Foo.kt SymbolProcessor HogeFactory.kt FooFactory.kt Clean Build
59. Hoge.kt Foo.kt SymbolProcessor HogeFactory.kt FooFactory.kt Hoge.kt Foo.kt Bar.kt Changed New Clean Build 差分 Build
60. Hoge.kt Foo.kt SymbolProcessor HogeFactory.kt FooFactory.kt Hoge.kt Foo.kt SymbolProcessor Bar.kt Changed New Clean Build 差分 Build
61. Hoge.kt Foo.kt SymbolProcessor HogeFactory.kt FooFactory.kt Hoge.kt Foo.kt SymbolProcessor HogeFactory.kt FooFactory.kt Bar.kt BarFactory.kt Changed New Clean Build 差分 Build
62. val symbols = resolver.getSymbolsWithAnnotation("...") symbols.forEach { val file = codeGenerator.createNewFile( Dependencies(aggregating = false, it.containingFile!!), "...", "..." ) // コード生成 }
63. val symbols = resolver.getSymbolsWithAnnotation("...") symbols.forEach { val file = codeGenerator.createNewFile( Dependencies(aggregating = false, it.containingFile!!), "...", "..." ) // コード生成 }
64. Dependencies(aggregating = false) Hoge.kt Foo.kt SymbolProcessor
65. Hoge.kt Foo.kt SymbolProcessor Bar.kt New Changed Hoge.kt Bar.kt Dependencies(aggregating = false)
66. Dependencies(aggregating = false, Hoge, Foo) SymbolProcessor Hoge.kt Foo.kt
67. Dependencies(aggregating = false, Hoge, Foo) Hoge.kt Foo.kt SymbolProcessor Changed Hoge.kt Foo.kt
68. Dependencies(aggregating = true, Hoge) Hoge.kt Foo.kt SymbolProcessor
69. Dependencies(aggregating = true, Hoge) Hoge.kt Foo.kt SymbolProcessor Changed Hoge.kt Foo.kt
70. KSP対応状況
71. KSP対応状況 • Room ◦ https://developer.android.com/jetpack/androidx/releases/room#2.3.0-beta02 • Moshi ◦ https://github.com/ZacSweers/MoshiX/tree/main/moshi-ksp • Kotshi ◦ https://github.com/ansman/kotshi
72. Thank you