com.github.avrokotlin.avro4k.internal.EnumResolver.kt Maven / Gradle / Ivy

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Avro binary format support for kotlin, built on top of kotlinx-serialization

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package com.github.avrokotlin.avro4k.internal

import com.github.avrokotlin.avro4k.AvroEnumDefault
import kotlinx.serialization.descriptors.SerialDescriptor
import org.apache.avro.util.WeakIdentityHashMap

internal class EnumResolver {
    private val defaultIndexCache: MutableMap = WeakIdentityHashMap()

    private data class EnumDefault(val index: Int?)

    fun getDefaultValueIndex(enumDescriptor: SerialDescriptor): Int? {
        return defaultIndexCache.getOrPut(enumDescriptor) {
            loadCache(enumDescriptor)
        }.index
    }

    private fun loadCache(enumDescriptor: SerialDescriptor): EnumDefault {
        var foundIndex: Int? = null
        for (i in 0 until enumDescriptor.elementsCount) {
            if (enumDescriptor.getElementAnnotations(i).any { it is AvroEnumDefault }) {
                if (foundIndex != null) {
                    throw UnsupportedOperationException("Multiple default values found in enum $enumDescriptor")
                }
                foundIndex = i
            }
        }
        return EnumDefault(foundIndex)
    }
}