se.ansman.kotshi.kapt.MetadataAccessor.kt Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of compiler Show documentation
An annotations processor that generates Moshi adapters from Kotlin data classes
The newest version!
package se.ansman.kotshi.kapt

import com.squareup.kotlinpoet.ClassName
import com.squareup.kotlinpoet.DelicateKotlinPoetApi
import com.squareup.kotlinpoet.TypeSpec
import com.squareup.kotlinpoet.asClassName
import com.squareup.kotlinpoet.metadata.specs.ClassInspector
import com.squareup.kotlinpoet.metadata.specs.toTypeSpec
import com.squareup.kotlinpoet.tag
import se.ansman.kotshi.Errors.javaClassNotSupported
import javax.lang.model.element.Element
import javax.lang.model.element.TypeElement
import kotlin.metadata.KmClass
import kotlin.metadata.isLocalClassName
import kotlin.metadata.jvm.KotlinClassMetadata

class MetadataAccessor(private val classInspector: ClassInspector) {
    private val metadataPerType = mutableMapOf()
    private val kmClassPerMetadata = mutableMapOf()
    private val typeSpecPerKmClass = mutableMapOf()

    @OptIn(DelicateKotlinPoetApi::class) // OK because we are using the class name for comparison
    fun getMetadataOrNull(type: Element): Metadata? =
        metadataPerType.getOrPut((type as TypeElement).asClassName()) {
            type.getAnnotation(Metadata::class.java)
        }

    fun getMetadata(type: Element): Metadata =
        getMetadataOrNull(type)
            ?: throw KaptProcessingError(javaClassNotSupported, type)

    fun getLanguageVersion(type: Element): KotlinVersion = getMetadata(type).languageVersion

    fun getKmClass(metadata: Metadata): KmClass = kmClassPerMetadata.getOrPut(metadata) {
        (KotlinClassMetadata.readLenient(metadata) as KotlinClassMetadata.Class).kmClass
    }
    fun getKmClass(type: Element): KmClass = getKmClass(getMetadata(type))
    fun getKmClassOrNull(type: Element): KmClass? = getMetadataOrNull(type)?.let(::getKmClass)

    fun getTypeSpec(type: Element): TypeSpec = getTypeSpec(getKmClass(type))
    fun getTypeSpecOrNull(type: Element): TypeSpec? = getKmClassOrNull(type)?.let(::getTypeSpec)

    fun getTypeSpec(metadata: KmClass): TypeSpec =
        typeSpecPerKmClass.getOrPut(metadata) {
            metadata.toTypeSpec(classInspector)
                .toBuilder()
                .tag(createClassName(metadata.name))
                .build()
        }
}

fun createClassName(kotlinMetadataName: String): ClassName {
    require(!kotlinMetadataName.isLocalClassName()) {
        "Local/anonymous classes are not supported!"
    }
    // Top-level: package/of/class/MyClass
    // Nested A:  package/of/class/MyClass.NestedClass
    val simpleName = kotlinMetadataName.substringAfterLast(
        '/', // Drop the package name, e.g. "package/of/class/"
        '.' // Drop any enclosing classes, e.g. "MyClass."
    )
    val packageName = kotlinMetadataName.substringBeforeLast(
        delimiter = "/",
        missingDelimiterValue = ""
    )
    val simpleNames = kotlinMetadataName.removeSuffix(simpleName)
        .removeSuffix(".") // Trailing "." if any
        .removePrefix(packageName)
        .removePrefix("/")
        .let {
            if (it.isNotEmpty()) {
                it.split(".")
            } else {
                // Don't split, otherwise we end up with an empty string as the first element!
                emptyList()
            }
        }
        .plus(simpleName)

    return ClassName(
        packageName = packageName.replace("/", "."),
        simpleNames = simpleNames
    )
}

@Suppress("SameParameterValue")
private fun String.substringAfterLast(vararg delimiters: Char): String {
    val index = lastIndexOfAny(delimiters)
    return if (index == -1) this else substring(index + 1, length)
}

val Metadata.languageVersion: KotlinVersion
    get() = KotlinVersion(
        major = metadataVersion[0],
        minor = metadataVersion[1],
        patch = metadataVersion.getOrElse(2) { 0 },
    )

val Metadata.supportsCreatingAnnotationsWithConstructor: Boolean
    get() = languageVersion.isAtLeast(1, 6)