se.ansman.kotshi.ksp.generators.ObjectAdapterGenerator.kt Maven / Gradle / Ivy

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An annotations processor that generates Moshi adapters from Kotlin data classes

There is a newer version: 3.0.0

package se.ansman.kotshi.ksp.generators

import com.google.devtools.ksp.processing.Resolver
import com.google.devtools.ksp.processing.SymbolProcessorEnvironment
import com.google.devtools.ksp.symbol.ClassKind
import com.google.devtools.ksp.symbol.KSClassDeclaration
import com.squareup.kotlinpoet.FunSpec
import com.squareup.kotlinpoet.KModifier
import com.squareup.kotlinpoet.TypeSpec
import com.squareup.kotlinpoet.jvm.throws
import se.ansman.kotshi.GlobalConfig
import se.ansman.kotshi.addControlFlow
import se.ansman.kotshi.addElse
import se.ansman.kotshi.addIfElse
import se.ansman.kotshi.kapt.generators.ioException
import se.ansman.kotshi.kapt.generators.jsonDataException
import se.ansman.kotshi.kapt.generators.jsonReaderToken
import se.ansman.kotshi.kapt.generators.readerParameter
import se.ansman.kotshi.kapt.generators.writerParameter
import se.ansman.kotshi.nullable

class ObjectAdapterGenerator(
    environment: SymbolProcessorEnvironment,
    resolver: Resolver,
    element: KSClassDeclaration,
    globalConfig: GlobalConfig
) : AdapterGenerator(environment, resolver, element, globalConfig) {
    init {
        require(element.classKind == ClassKind.OBJECT)
    }

    override fun TypeSpec.Builder.addMethods() {
        this
            .addFunction(FunSpec.builder("toJson")
                .addModifiers(KModifier.OVERRIDE)
                .throws(ioException)
                .addParameter(writerParameter)
                .addParameter(value)
                .addIfElse("%N == null", value) {
                    addStatement("%N.nullValue()", writerParameter)
                }
                .addElse {
                    addStatement("%N.beginObject()", writerParameter)
                    for ((key, value) in getPolymorphicLabels()) {
                        addStatement("%N.name(%S).value(%S)", writerParameter, key, value)
                    }
                    addStatement("%N.endObject()", writerParameter)
                }
                .build())
            .addFunction(FunSpec.builder("fromJson")
                .addModifiers(KModifier.OVERRIDE)
                .throws(ioException)
                .addParameter(readerParameter)
                .returns(typeName.nullable())
                .addControlFlow("return when·(%N.peek())", readerParameter) {
                    addStatement("%T.NULL·-> %N.nextNull()", jsonReaderToken, readerParameter)
                    addControlFlow("%T.BEGIN_OBJECT·->", jsonReaderToken) {
                        addStatement("%N.skipValue()", readerParameter)
                        addStatement("%T", typeName)
                    }
                    addStatement("else·-> throw·%T(%P)", jsonDataException, "Expected BEGIN_OBJECT but was \${${readerParameter.name}.peek()} at path \${${readerParameter.name}.path}")
                }
                .build())
    }
}