From 95ba93d6b16114355add1cf9f3769349918d5365 Mon Sep 17 00:00:00 2001
From: Chuckame <Chuckame@users.noreply.github.com>
Date: Wed, 7 Feb 2024 13:03:00 +0100
Subject: [PATCH] add writer schema for decoding

---
 .../com/github/avrokotlin/avro4k/Avro2.kt     | 35 ++++++++++---------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/src/main/kotlin/com/github/avrokotlin/avro4k/Avro2.kt b/src/main/kotlin/com/github/avrokotlin/avro4k/Avro2.kt
index ef8010d8..a5e01350 100644
--- a/src/main/kotlin/com/github/avrokotlin/avro4k/Avro2.kt
+++ b/src/main/kotlin/com/github/avrokotlin/avro4k/Avro2.kt
@@ -183,31 +183,31 @@ sealed class AvroSerializationDelegate {
     /**
      * The created encoder is stateful, so you can use this encoder for multiple encodings.
      */
-    fun <T> Avro2.newEncoder(writerSchema: Schema, serializer: SerializationStrategy<T>, outputStream: OutputStream): Encoder {
+    fun <T> newEncoder(avro: Avro2, writerSchema: Schema, serializer: SerializationStrategy<T>, outputStream: OutputStream): Encoder {
         val avroEncoder = when (encodedAs) {
             EncodedAs.BINARY -> EncoderFactory.get().binaryEncoder(outputStream, null)
             EncodedAs.JSON_COMPACT -> EncoderFactory.get().jsonEncoder(writerSchema, outputStream, false)
             EncodedAs.JSON_PRETTY -> EncoderFactory.get().jsonEncoder(writerSchema, outputStream, true)
         }
-        return newEncoder(writerSchema, serializer, avroEncoder)
+        return newEncoder(avro, writerSchema, serializer, avroEncoder)
     }
 
     /**
      * The created decoder is stateful, so you can use this decoder for multiple decodings.
      */
-    fun <T> Avro2.newDecoder(readerSchema: Schema, deserializer: DeserializationStrategy<T>, inputStream: InputStream): Decoder {
+    fun <T> newDecoder(avro: Avro2, readerSchema: Schema, writerSchema: Schema, deserializer: DeserializationStrategy<T>, inputStream: InputStream): Decoder {
         val avroDecoder = when (encodedAs) {
             EncodedAs.BINARY -> DecoderFactory.get().binaryDecoder(inputStream, null)
             EncodedAs.JSON_COMPACT, EncodedAs.JSON_PRETTY -> DecoderFactory.get().jsonDecoder(readerSchema, inputStream)
         }
-        return newDecoder(readerSchema, deserializer, avroDecoder)
+        return newDecoder(avro, readerSchema, writerSchema, deserializer, avroDecoder)
     }
 
-    internal fun <T> Avro2.newEncoder(writerSchema: Schema, serializer: SerializationStrategy<T>, avroEncoder: AvroEncoder): Encoder {
+    internal fun <T> newEncoder(avro: Avro2, writerSchema: Schema, serializer: SerializationStrategy<T>, avroEncoder: AvroEncoder): Encoder {
         TODO()
     }
 
-    internal fun <T> Avro2.newDecoder(readerSchema: Schema, deserializer: DeserializationStrategy<T>, avroDecoder: AvroDecoder): Decoder {
+    internal fun <T> newDecoder(avro: Avro2, readerSchema: Schema, writerSchema: Schema, deserializer: DeserializationStrategy<T>, avroDecoder: AvroDecoder): Decoder {
         TODO()
     }
 
@@ -229,24 +229,24 @@ sealed class AvroSerializationDelegate {
          */
         data class Pure(override val encodedAs: EncodedAs) : AvroSerializationDelegate() {
             override fun <T> encodeValue(avro: Avro2, writerSchema: Schema, serializer: SerializationStrategy<T>, value: T, outputStream: OutputStream) {
-                avro.newEncoder(writerSchema, serializer, outputStream)
+                newEncoder(avro, writerSchema, serializer, outputStream)
                     .encodeSerializableValue(serializer, value)
             }
 
             override fun <T> encodeSequence(avro: Avro2, writerSchema: Schema, serializer: SerializationStrategy<T>, sequence: Sequence<T>, outputStream: OutputStream) {
-                val encoder = avro.newEncoder(writerSchema, serializer, outputStream)
+                val encoder = newEncoder(avro, writerSchema, serializer, outputStream)
                 sequence.forEach {
                     encoder.encodeSerializableValue(serializer, it)
                 }
             }
 
             override fun <T> decodeValue(avro: Avro2, readerSchema: Schema, deserializer: DeserializationStrategy<T>, inputStream: InputStream): T =
-                avro.newDecoder(readerSchema, deserializer, inputStream)
+                newDecoder(avro, readerSchema, readerSchema, deserializer, inputStream)
                     .decodeSerializableValue(deserializer)
 
             override fun <T> decodeSequence(avro: Avro2, readerSchema: Schema, deserializer: DeserializationStrategy<T>, inputStream: InputStream): Sequence<T> =
                 sequence<T> {
-                    val decoder = avro.newDecoder(readerSchema, deserializer, inputStream)
+                    val decoder = newDecoder(avro, readerSchema, readerSchema, deserializer, inputStream)
                     while (inputStream.available() > 0) {
                         yield(decoder.decodeSerializableValue(deserializer))
                     }
@@ -288,14 +288,14 @@ sealed class AvroSerializationDelegate {
                 }
 
                 override fun write(datum: T, encoder: AvroEncoder) {
-                    avro.newEncoder(writerSchema, serializer, encoder)
+                    newEncoder(avro, writerSchema, serializer, encoder)
                         .encodeSerializableValue(serializer, datum)
                 }
             }
 
             override fun <T> decodeSequence(avro: Avro2, readerSchema: Schema, deserializer: DeserializationStrategy<T>, inputStream: InputStream): Sequence<T> =
                 sequence {
-                    val datumReader: DatumReader<T> = KotlinxSerializationDatumReader(deserializer, avro)
+                    val datumReader: DatumReader<T> = KotlinxSerializationDatumReader(deserializer, avro, readerSchema)
                     DataFileStream(inputStream, datumReader).use { dataFileStream ->
                         yieldAll(dataFileStream.iterator())
                     }
@@ -304,15 +304,16 @@ sealed class AvroSerializationDelegate {
             internal class KotlinxSerializationDatumReader<T>(
                 private val deserializer: DeserializationStrategy<T>,
                 private val avro: Avro2,
+                private val readerSchema: Schema,
             ) : DatumReader<T> {
-                private lateinit var readerSchema: Schema
+                private lateinit var writerSchema: Schema
 
                 override fun setSchema(schema: Schema) {
-                    readerSchema = schema
+                    writerSchema = schema
                 }
 
                 override fun read(reuse: T?, decoder: AvroDecoder): T {
-                    return avro.newDecoder(readerSchema, deserializer, decoder)
+                    return newDecoder(avro, readerSchema, writerSchema, deserializer, decoder)
                         .decodeSerializableValue(deserializer)
                 }
             }
@@ -345,7 +346,7 @@ sealed class AvroSerializationDelegate {
                 outputStream.write(MAGIC_BYTE)
                 outputStream.write(FORMAT_VERSION)
                 outputStream.write(writerSchema.crc64avro())
-                avro.newEncoder(writerSchema, serializer, outputStream)
+                newEncoder(avro, writerSchema, serializer, outputStream)
                     .encodeSerializableValue(serializer, value)
             }
 
@@ -356,7 +357,7 @@ sealed class AvroSerializationDelegate {
 
                 checkNotNull(writerSchema) { "schema not found for the given object's schema fingerprint" }
 
-                return avro.newDecoder(readerSchema, deserializer, inputStream)
+                return newDecoder(avro, readerSchema, writerSchema, deserializer, inputStream)
                     .decodeSerializableValue(deserializer)
             }