1 files changed, 72 insertions, 0 deletions
diff --git a/benchmark/src/jmh/kotlin/kotlinx/benchmarks/json/ContextualOverheadBenchmark.kt b/benchmark/src/jmh/kotlin/kotlinx/benchmarks/json/ContextualOverheadBenchmark.kt
new file mode 100644
index 00000000..2773cfc2
--- /dev/null
+++ b/benchmark/src/jmh/kotlin/kotlinx/benchmarks/json/ContextualOverheadBenchmark.kt
@@ -0,0 +1,72 @@
+package kotlinx.benchmarks.json
+
+import kotlinx.serialization.*
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.descriptors.buildClassSerialDescriptor
+import kotlinx.serialization.descriptors.element
+import kotlinx.serialization.encoding.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.modules.*
+import org.openjdk.jmh.annotations.*
+import java.util.concurrent.*
+
+@Warmup(iterations = 7, time = 1)
+@Measurement(iterations = 5, time = 1)
+@BenchmarkMode(Mode.Throughput)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Benchmark)
+@Fork(1)
+open class ContextualOverheadBenchmark {
+    @Serializable
+    data class Holder(val data: @Contextual Data)
+
+    class Data(val a: Int, val b: String)
+
+    object DataSerializer: KSerializer<Data> {
+        override val descriptor: SerialDescriptor = buildClassSerialDescriptor("Serializer") {
+            element<Int>("a")
+            element<String>("b")
+        }
+
+        override fun deserialize(decoder: Decoder): Data {
+            return decoder.decodeStructure(descriptor) {
+                var a = 0
+                var b = ""
+                while (true) {
+                    when (val index = decodeElementIndex(descriptor)) {
+                        0 -> a = decodeIntElement(descriptor, 0)
+                        1 -> b = decodeStringElement(descriptor, 1)
+                        CompositeDecoder.DECODE_DONE -> break
+                        else -> error("Unexpected index: $index")
+                    }
+                }
+                Data(a, b)
+            }
+        }
+
+        override fun serialize(encoder: Encoder, value: Data) {
+            encoder.encodeStructure(descriptor) {
+                encodeIntElement(descriptor, 0, value.a)
+                encodeStringElement(descriptor, 1, value.b)
+            }
+        }
+
+    }
+
+    private val module = SerializersModule {
+        contextual(DataSerializer)
+    }
+
+    private val json = Json { serializersModule = module }
+
+    private val holder = Holder(Data(1, "abc"))
+    private val holderString = json.encodeToString(holder)
+    private val holderSerializer = serializer<Holder>()
+
+    @Benchmark
+    fun decode() = json.decodeFromString(holderSerializer, holderString)
+
+    @Benchmark
+    fun encode() = json.encodeToString(holderSerializer, holder)
+
+}