use delegation instead of inheritance for special value serialization

Author: vpodlesnyak

firebase-common/src/commonMain/kotlin/dev/gitlive/firebase/serializers.kt

@@ -108,7 +108,7 @@ class FirebaseListSerializer : KSerializer<Iterable<Any?>> {
  * A special case of serializer for values natively supported by Firebase and
  * don't require an additional encoding/decoding.
  */
-abstract class SpecialValueSerializer<T>(
+class SpecialValueSerializer<T>(
     serialName: String,
     private val toNativeValue: (T) -> Any?,
     private val fromNativeValue: (Any?) -> T

firebase-database/build.gradle.kts

@@ -98,7 +98,7 @@ kotlin {
         val commonMain by getting {
             dependencies {
                 api(project(":firebase-app"))
-                api(project(":firebase-common"))
+                implementation(project(":firebase-common"))
             }
         }
 

firebase-database/src/commonMain/kotlin/dev/gitlive/firebase/database/ServerValue.kt

@@ -3,6 +3,7 @@ package dev.gitlive.firebase.database
 import dev.gitlive.firebase.FirebaseDecoder
 import dev.gitlive.firebase.FirebaseEncoder
 import dev.gitlive.firebase.SpecialValueSerializer
+import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.SerializationException
 
@@ -18,7 +19,7 @@ expect class ServerValue internal constructor(nativeValue: Any){
 }
 
 /** Serializer for [ServerValue]. Must be used with [FirebaseEncoder]/[FirebaseDecoder].*/
-object ServerValueSerializer: SpecialValueSerializer<ServerValue>(
+object ServerValueSerializer: KSerializer<ServerValue> by SpecialValueSerializer(
     serialName = "ServerValue",
     toNativeValue = ServerValue::nativeValue,
     fromNativeValue = { raw ->

firebase-firestore/build.gradle.kts

@@ -99,7 +99,7 @@ kotlin {
         val commonMain by getting {
             dependencies {
                 api(project(":firebase-app"))
-                api(project(":firebase-common"))
+                implementation(project(":firebase-common"))
             }
         }
 

firebase-firestore/src/commonMain/kotlin/dev/gitlive/firebase/firestore/GeoPoint.kt

@@ -1,6 +1,7 @@
 package dev.gitlive.firebase.firestore
 
 import dev.gitlive.firebase.SpecialValueSerializer
+import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.SerializationException
 
@@ -17,7 +18,7 @@ expect class GeoPoint internal constructor(nativeValue: NativeGeoPoint) {
 }
 
 /** Serializer for [GeoPoint]. If used with [FirebaseEncoder] performs serialization using native Firebase mechanisms. */
-object GeoPointSerializer : SpecialValueSerializer<GeoPoint>(
+object GeoPointSerializer : KSerializer<GeoPoint> by SpecialValueSerializer(
     serialName = "GeoPoint",
     toNativeValue = GeoPoint::nativeValue,
     fromNativeValue = { value ->

firebase-firestore/src/commonMain/kotlin/dev/gitlive/firebase/firestore/Timestamp.kt

@@ -4,6 +4,7 @@ import dev.gitlive.firebase.FirebaseDecoder
 import dev.gitlive.firebase.FirebaseEncoder
 import dev.gitlive.firebase.SpecialValueSerializer
 import dev.gitlive.firebase.firestore.DoubleAsTimestampSerializer.serverTimestamp
+import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.SerializationException
 import kotlin.time.Duration
@@ -47,7 +48,7 @@ fun Timestamp.Companion.fromMilliseconds(milliseconds: Double): Timestamp = from
 fun Timestamp.toMilliseconds(): Double = toDuration().toDouble(DurationUnit.MILLISECONDS)
 
 /** A serializer for [BaseTimestamp]. Must be used with [FirebaseEncoder]/[FirebaseDecoder]. */
-object BaseTimestampSerializer : SpecialValueSerializer<BaseTimestamp>(
+object BaseTimestampSerializer : KSerializer<BaseTimestamp> by SpecialValueSerializer(
     serialName = "Timestamp",
     toNativeValue = { value ->
         when (value) {
@@ -66,7 +67,7 @@ object BaseTimestampSerializer : SpecialValueSerializer<BaseTimestamp>(
 )
 
 /** A serializer for [Timestamp]. Must be used with [FirebaseEncoder]/[FirebaseDecoder]. */
-object TimestampSerializer : SpecialValueSerializer<Timestamp>(
+object TimestampSerializer : KSerializer<Timestamp> by SpecialValueSerializer(
     serialName = "Timestamp",
     toNativeValue = Timestamp::nativeValue,
     fromNativeValue = { value ->
@@ -78,7 +79,7 @@ object TimestampSerializer : SpecialValueSerializer<Timestamp>(
 )
 
 /** A serializer for [Timestamp.ServerTimestamp]. Must be used with [FirebaseEncoder]/[FirebaseDecoder]. */
-object ServerTimestampSerializer : SpecialValueSerializer<Timestamp.ServerTimestamp>(
+object ServerTimestampSerializer : KSerializer<Timestamp.ServerTimestamp> by SpecialValueSerializer(
     serialName = "Timestamp",
     toNativeValue = { FieldValue.serverTimestamp.nativeValue },
     fromNativeValue = { value ->
@@ -90,7 +91,7 @@ object ServerTimestampSerializer : SpecialValueSerializer<Timestamp.ServerTimest
 )
 
 /** A serializer for a Double field which is stored as a Timestamp. */
-object DoubleAsTimestampSerializer : SpecialValueSerializer<Double>(
+object DoubleAsTimestampSerializer : KSerializer<Double> by SpecialValueSerializer(
     serialName = "Timestamp",
     toNativeValue = { value ->
         when(value) {

firebase-firestore/src/commonMain/kotlin/dev/gitlive/firebase/firestore/firestore.kt

@@ -7,6 +7,7 @@ package dev.gitlive.firebase.firestore
 import dev.gitlive.firebase.*
 import kotlinx.coroutines.flow.Flow
 import kotlinx.serialization.DeserializationStrategy
+import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.SerializationException
 import kotlinx.serialization.SerializationStrategy
@@ -164,7 +165,7 @@ expect class DocumentReference internal constructor(nativeValue: NativeDocumentR
 /**
  * A serializer for [DocumentReference]. If used with [FirebaseEncoder] performs serialization using native Firebase mechanisms.
  */
-object DocumentReferenceSerializer : SpecialValueSerializer<DocumentReference>(
+object DocumentReferenceSerializer : KSerializer<DocumentReference> by SpecialValueSerializer(
     serialName = "DocumentReference",
     toNativeValue = DocumentReference::nativeValue,
     fromNativeValue = { value ->
@@ -282,7 +283,7 @@ expect class FieldValue internal constructor(nativeValue: Any) {
 }
 
 /** A serializer for [FieldValue]. Must be used in conjunction with [FirebaseEncoder]. */
-object FieldValueSerializer : SpecialValueSerializer<FieldValue>(
+object FieldValueSerializer : KSerializer<FieldValue> by SpecialValueSerializer(
     serialName = "FieldValue",
     toNativeValue = FieldValue::nativeValue,
     fromNativeValue = { raw ->