io.circe.shapes.CoproductInstances.scala Maven / Gradle / Ivy
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/*
* Copyright 2024 circe
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.circe.shapes
import io.circe.Decoder
import io.circe.DecodingFailure
import io.circe.Encoder
import io.circe.HCursor
import io.circe.Json
import shapeless.:+:
import shapeless.CNil
import shapeless.Coproduct
import shapeless.Inl
import shapeless.Inr
trait CoproductInstances {
implicit final val decodeCNil: Decoder[CNil] = new Decoder[CNil] {
def apply(c: HCursor): Decoder.Result[CNil] =
Left(DecodingFailure("JSON decoding to CNil should never happen", c.history))
}
implicit final val encodeCNil: Encoder[CNil] = new Encoder[CNil] {
def apply(a: CNil): Json = sys.error("Cannot encode CNil")
}
implicit final def decodeCCons[L, R <: Coproduct](implicit
decodeL: Decoder[L],
decodeR: Decoder[R]
): Decoder[L :+: R] = decodeL.map(Inl(_)).or(decodeR.map(Inr(_)))
implicit final def encodeCCons[L, R <: Coproduct](implicit
encodeL: Encoder[L],
encodeR: Encoder[R]
): Encoder[L :+: R] = new Encoder[L :+: R] {
def apply(a: L :+: R): Json = a match {
case Inl(l) => encodeL(l)
case Inr(r) => encodeR(r)
}
}
}