1 files changed, 78 insertions, 0 deletions
diff --git a/runtime/commonMain/src/kotlinx/serialization/json/JsonConfiguration.kt b/runtime/commonMain/src/kotlinx/serialization/json/JsonConfiguration.kt
new file mode 100644
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+++ b/runtime/commonMain/src/kotlinx/serialization/json/JsonConfiguration.kt
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2017-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.serialization.json
+
+import kotlinx.serialization.*
+import kotlin.jvm.*
+
+/**
+ * The class responsible for JSON-specific customizable behaviour in [Json] format.
+ *
+ * Options list:
+ * [encodeDefaults] specifies whether default values are encoded.
+ * [strictMode] enables strict mode, which prohibits unknown keys in the JSON and non-numerical values in floating point numbers.
+ * [unquoted] specifies whether keys and values should be quoted;
+ * [prettyPrint] specifies whether resulting JSON should be pretty-printed.
+ * [indent] specifies indent string to use with [prettyPrint] mode.
+ * [useArrayPolymorphism] switches polymorphic serialization to the default array format.
+ * [classDiscriminator] name of the class descriptor property in polymorphic serialization.
+ *
+ * This class is marked with [UnstableDefault]: its semantics may be changes in the next releases, e.g.
+ * additional flag may be introduced or default parameter values may be changed.
+ */
+public data class JsonConfiguration @UnstableDefault constructor(
+    @JvmField internal val encodeDefaults: Boolean = true,
+    @JvmField internal val strictMode: Boolean = true,
+    @JvmField internal val unquoted: Boolean = false,
+    @JvmField internal val prettyPrint: Boolean = false,
+    @JvmField internal val indent: String = defaultIndent,
+    @JvmField internal val useArrayPolymorphism: Boolean = false,
+    @JvmField internal val classDiscriminator: String = defaultDiscriminator,
+    @Deprecated(message = "Custom update modes are not fully supported", level = DeprecationLevel.WARNING)
+    @JvmField internal val updateMode: UpdateMode = UpdateMode.OVERWRITE) {
+
+    init {
+        if (useArrayPolymorphism) require(classDiscriminator == defaultDiscriminator) {
+            "Class discriminator should not be specified when array polymorphism is specified"
+        }
+
+        if (!prettyPrint) require(indent == defaultIndent) {
+            "Indent should not be specified when default printing mode is used"
+        }
+    }
+
+    companion object {
+        @JvmStatic
+        private val defaultIndent = "    "
+        @JvmStatic
+        private val defaultDiscriminator = "type"
+
+        /**
+         * Default recommended configuration for [Json] format.
+         *
+         * This configuration is a recommended way to configure JSON by default, but due to the library evolution (until it hits 1.0.0 version)
+         * we can't guarantee backwards compatibility and it is likely to change.
+         */
+        @JvmStatic
+        @UnstableDefault
+        public val Default = JsonConfiguration()
+
+        /**
+         * Stable [JsonConfiguration] that is guaranteed to preserve its semantics between releases.
+         * To have a stable base in your [Json] configuration you can use `Stable.copy(param = ...)`
+         */
+        @UseExperimental(UnstableDefault::class)
+        @JvmStatic
+        public val Stable = JsonConfiguration(
+            encodeDefaults = true,
+            strictMode = true,
+            unquoted = false,
+            prettyPrint = false,
+            indent = defaultIndent,
+            useArrayPolymorphism = false,
+            classDiscriminator = defaultDiscriminator
+        )
+    }
+}