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/*
* Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
*/
package kotlinx.serialization.json.internal
import kotlinx.serialization.*
import kotlinx.serialization.descriptors.*
import kotlinx.serialization.modules.*
import kotlin.reflect.*
@OptIn(ExperimentalSerializationApi::class)
internal class PolymorphismValidator(
private val useArrayPolymorphism: Boolean,
private val discriminator: String
) : SerializersModuleCollector {
override fun <T : Any> contextual(
kClass: KClass<T>,
provider: (typeArgumentsSerializers: List<KSerializer<*>>) -> KSerializer<*>
) {
// Nothing here
}
override fun <Base : Any, Sub : Base> polymorphic(
baseClass: KClass<Base>,
actualClass: KClass<Sub>,
actualSerializer: KSerializer<Sub>
) {
val descriptor = actualSerializer.descriptor
checkKind(descriptor, actualClass)
if (!useArrayPolymorphism) {
// Collisions with "type" can happen only for JSON polymorphism
checkDiscriminatorCollisions(descriptor, actualClass)
}
}
private fun checkKind(descriptor: SerialDescriptor, actualClass: KClass<*>) {
val kind = descriptor.kind
if (kind is PolymorphicKind || kind == SerialKind.CONTEXTUAL) {
throw IllegalArgumentException("Serializer for ${actualClass.simpleName} can't be registered as a subclass for polymorphic serialization " +
"because its kind $kind is not concrete. To work with multiple hierarchies, register it as a base class.")
}
if (useArrayPolymorphism) return
/*
* For this kind we can't intercept the JSON object {} in order to add "type: ...".
* Except for maps that just can clash and accidentally overwrite the type.
*/
if (kind == StructureKind.LIST || kind == StructureKind.MAP
|| kind is PrimitiveKind
|| kind is SerialKind.ENUM
) {
throw IllegalArgumentException(
"Serializer for ${actualClass.simpleName} of kind $kind cannot be serialized polymorphically with class discriminator."
)
}
}
private fun checkDiscriminatorCollisions(
descriptor: SerialDescriptor,
actualClass: KClass<*>
) {
for (i in 0 until descriptor.elementsCount) {
val name = descriptor.getElementName(i)
if (name == discriminator) {
throw IllegalArgumentException(
"Polymorphic serializer for $actualClass has property '$name' that conflicts " +
"with JSON class discriminator. You can either change class discriminator in JsonConfiguration, " +
"rename property with @SerialName annotation " +
"or fall back to array polymorphism"
)
}
}
}
override fun <Base : Any> polymorphicDefaultSerializer(
baseClass: KClass<Base>,
defaultSerializerProvider: (value: Base) -> SerializationStrategy<Base>?
) {
// Nothing here
}
override fun <Base : Any> polymorphicDefaultDeserializer(
baseClass: KClass<Base>,
defaultDeserializerProvider: (className: String?) -> DeserializationStrategy<out Base>?
) {
// Nothing here
}
}
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