1 /*
2 * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
3 */
4 package kotlinx.serialization.modules
5
6 import kotlinx.serialization.*
7 import kotlinx.serialization.internal.*
8 import kotlin.jvm.*
9 import kotlin.reflect.*
10
11 /**
12 * Returns a [SerializersModule] which has one class with one [serializer] for [ContextualSerializer].
13 */
serializersModuleOfnull14 public fun <T : Any> serializersModuleOf(kClass: KClass<T>, serializer: KSerializer<T>): SerializersModule =
15 SerializersModule { contextual(kClass, serializer) }
16
17 /**
18 * Returns a [SerializersModule] which has one class with one [serializer] for [ContextualSerializer].
19 */
serializersModuleOfnull20 public inline fun <reified T : Any> serializersModuleOf(serializer: KSerializer<T>): SerializersModule =
21 serializersModuleOf(T::class, serializer)
22
23 /**
24 * A builder function for creating a [SerializersModule].
25 * Serializers can be added via [SerializersModuleBuilder.contextual] or [SerializersModuleBuilder.polymorphic].
26 * Since [SerializersModuleBuilder] also implements [SerialModuleCollector],
27 * it is possible to copy whole another module to this builder with [SerializersModule.dumpTo]
28 */
29 @Suppress("FunctionName")
30 public inline fun SerializersModule(builderAction: SerializersModuleBuilder.() -> Unit): SerializersModule {
31 val builder = SerializersModuleBuilder()
32 builder.builderAction()
33 return builder.build()
34 }
35
36 /**
37 * A [SerializersModule] which is empty and returns `null` from each method.
38 */
39 @Suppress("FunctionName")
EmptySerializersModulenull40 public fun EmptySerializersModule(): SerializersModule = @Suppress("DEPRECATION") EmptySerializersModule
41
42 /**
43 * A builder class for [SerializersModule] DSL. To create an instance of builder, use [SerializersModule] factory function.
44 */
45 @OptIn(ExperimentalSerializationApi::class)
46 public class SerializersModuleBuilder @PublishedApi internal constructor() : SerializersModuleCollector {
47 private val class2ContextualProvider: MutableMap<KClass<*>, ContextualProvider> = hashMapOf()
48 private val polyBase2Serializers: MutableMap<KClass<*>, MutableMap<KClass<*>, KSerializer<*>>> = hashMapOf()
49 private val polyBase2DefaultSerializerProvider: MutableMap<KClass<*>, PolymorphicSerializerProvider<*>> = hashMapOf()
50 private val polyBase2NamedSerializers: MutableMap<KClass<*>, MutableMap<String, KSerializer<*>>> = hashMapOf()
51 private val polyBase2DefaultDeserializerProvider: MutableMap<KClass<*>, PolymorphicDeserializerProvider<*>> = hashMapOf()
52
53 /**
54 * Adds [serializer] associated with given [kClass] for contextual serialization.
55 * If [kClass] has generic type parameters, consider registering provider instead.
56 *
57 * Throws [SerializationException] if a module already has serializer or provider associated with a [kClass].
58 * To overwrite an already registered serializer, [SerializersModule.overwriteWith] can be used.
59 */
60 public override fun <T : Any> contextual(kClass: KClass<T>, serializer: KSerializer<T>): Unit =
61 registerSerializer(kClass, ContextualProvider.Argless(serializer))
62
63 /**
64 * Registers [provider] associated with given generic [kClass] for contextual serialization.
65 * When a serializer is requested from a module, provider is being called with type arguments serializers
66 * of the particular [kClass] usage.
67 *
68 * Example:
69 * ```
70 * class Holder(@Contextual val boxI: Box<Int>, @Contextual val boxS: Box<String>)
71 *
72 * val module = SerializersModule {
73 * // args[0] contains Int.serializer() or String.serializer(), depending on the property
74 * contextual(Box::class) { args -> BoxSerializer(args[0]) }
75 * }
76 * ```
77 *
78 * Throws [SerializationException] if a module already has provider or serializer associated with a [kClass].
79 * To overwrite an already registered serializer, [SerializersModule.overwriteWith] can be used.
80 */
81 public override fun <T : Any> contextual(
82 kClass: KClass<T>,
83 provider: (typeArgumentsSerializers: List<KSerializer<*>>) -> KSerializer<*>
84 ): Unit = registerSerializer(kClass, ContextualProvider.WithTypeArguments(provider))
85
86 /**
87 * Adds [serializer][actualSerializer] associated with given [actualClass] in the scope of [baseClass] for polymorphic serialization.
88 * Throws [SerializationException] if a module already has serializer associated with a [actualClass].
89 * To overwrite an already registered serializer, [SerializersModule.overwriteWith] can be used.
90 */
91 public override fun <Base : Any, Sub : Base> polymorphic(
92 baseClass: KClass<Base>,
93 actualClass: KClass<Sub>,
94 actualSerializer: KSerializer<Sub>
95 ) {
96 registerPolymorphicSerializer(baseClass, actualClass, actualSerializer)
97 }
98
99 /**
100 * Adds a default serializers provider associated with the given [baseClass] to the resulting module.
101 * [defaultSerializerProvider] is invoked when no polymorphic serializers for `value` in the scope of [baseClass] were found.
102 *
103 * Default serializers provider affects only serialization process. To affect deserialization process, use
104 * [SerializersModuleBuilder.polymorphicDefaultDeserializer].
105 *
106 * [defaultSerializerProvider] can be stateful and lookup a serializer for the missing type dynamically.
107 */
108 public override fun <Base : Any> polymorphicDefaultSerializer(
109 baseClass: KClass<Base>,
110 defaultSerializerProvider: (value: Base) -> SerializationStrategy<Base>?
111 ) {
112 registerDefaultPolymorphicSerializer(baseClass, defaultSerializerProvider, false)
113 }
114
115 /**
116 * Adds a default deserializers provider associated with the given [baseClass] to the resulting module.
117 * [defaultDeserializerProvider] is invoked when no polymorphic serializers associated with the `className`
118 * in the scope of [baseClass] were found. `className` could be `null` for formats that support nullable class discriminators
119 * (currently only `Json` with `useArrayPolymorphism` set to `false`).
120 *
121 * Default deserializers provider affects only deserialization process. To affect serialization process, use
122 * [SerializersModuleBuilder.polymorphicDefaultSerializer].
123 *
124 * [defaultDeserializerProvider] can be stateful and lookup a serializer for the missing type dynamically.
125 *
126 * @see PolymorphicModuleBuilder.defaultDeserializer
127 */
128 public override fun <Base : Any> polymorphicDefaultDeserializer(
129 baseClass: KClass<Base>,
130 defaultDeserializerProvider: (className: String?) -> DeserializationStrategy<Base>?
131 ) {
132 registerDefaultPolymorphicDeserializer(baseClass, defaultDeserializerProvider, false)
133 }
134
135 /**
136 * Copies the content of [module] module into the current builder.
137 */
138 public fun include(module: SerializersModule) {
139 module.dumpTo(this)
140 }
141
142 @JvmName("registerSerializer") // Don't mangle method name for prettier stack traces
143 internal fun <T : Any> registerSerializer(
144 forClass: KClass<T>,
145 provider: ContextualProvider,
146 allowOverwrite: Boolean = false
147 ) {
148 if (!allowOverwrite) {
149 val previous = class2ContextualProvider[forClass]
150 if (previous != null && previous != provider) {
151 // How can we provide meaningful name for WithTypeArgumentsProvider ?
152 throw SerializerAlreadyRegisteredException(
153 "Contextual serializer or serializer provider for $forClass already registered in this module"
154 )
155 }
156 }
157 class2ContextualProvider[forClass] = provider
158 }
159
160 @JvmName("registerDefaultPolymorphicSerializer") // Don't mangle method name for prettier stack traces
161 internal fun <Base : Any> registerDefaultPolymorphicSerializer(
162 baseClass: KClass<Base>,
163 defaultSerializerProvider: (value: Base) -> SerializationStrategy<Base>?,
164 allowOverwrite: Boolean
165 ) {
166 val previous = polyBase2DefaultSerializerProvider[baseClass]
167 if (previous != null && previous != defaultSerializerProvider && !allowOverwrite) {
168 throw IllegalArgumentException("Default serializers provider for $baseClass is already registered: $previous")
169 }
170 polyBase2DefaultSerializerProvider[baseClass] = defaultSerializerProvider
171 }
172
173 @JvmName("registerDefaultPolymorphicDeserializer") // Don't mangle method name for prettier stack traces
174 internal fun <Base : Any> registerDefaultPolymorphicDeserializer(
175 baseClass: KClass<Base>,
176 defaultDeserializerProvider: (className: String?) -> DeserializationStrategy<Base>?,
177 allowOverwrite: Boolean
178 ) {
179 val previous = polyBase2DefaultDeserializerProvider[baseClass]
180 if (previous != null && previous != defaultDeserializerProvider && !allowOverwrite) {
181 throw IllegalArgumentException("Default deserializers provider for $baseClass is already registered: $previous")
182 }
183 polyBase2DefaultDeserializerProvider[baseClass] = defaultDeserializerProvider
184 }
185
186 @JvmName("registerPolymorphicSerializer") // Don't mangle method name for prettier stack traces
187 internal fun <Base : Any, Sub : Base> registerPolymorphicSerializer(
188 baseClass: KClass<Base>,
189 concreteClass: KClass<Sub>,
190 concreteSerializer: KSerializer<Sub>,
191 allowOverwrite: Boolean = false
192 ) {
193 // Check for overwrite
194 val name = concreteSerializer.descriptor.serialName
195 val baseClassSerializers = polyBase2Serializers.getOrPut(baseClass, ::hashMapOf)
196 val previousSerializer = baseClassSerializers[concreteClass]
197 val names = polyBase2NamedSerializers.getOrPut(baseClass, ::hashMapOf)
198 if (allowOverwrite) {
199 // Remove previous serializers from name mapping
200 if (previousSerializer != null) {
201 names.remove(previousSerializer.descriptor.serialName)
202 }
203 // Update mappings
204 baseClassSerializers[concreteClass] = concreteSerializer
205 names[name] = concreteSerializer
206 return
207 }
208 // Overwrite prohibited
209 if (previousSerializer != null) {
210 if (previousSerializer != concreteSerializer) {
211 throw SerializerAlreadyRegisteredException(baseClass, concreteClass)
212 } else {
213 // Cleanup name mapping
214 names.remove(previousSerializer.descriptor.serialName)
215 }
216 }
217 val previousByName = names[name]
218 if (previousByName != null) {
219 val conflictingClass = polyBase2Serializers[baseClass]!!.asSequence().find { it.value === previousByName }
220 throw IllegalArgumentException(
221 "Multiple polymorphic serializers for base class '$baseClass' " +
222 "have the same serial name '$name': '$concreteClass' and '$conflictingClass'"
223 )
224 }
225 // Overwrite if no conflicts
226 baseClassSerializers[concreteClass] = concreteSerializer
227 names[name] = concreteSerializer
228 }
229
230 @PublishedApi
231 internal fun build(): SerializersModule =
232 SerialModuleImpl(class2ContextualProvider, polyBase2Serializers, polyBase2DefaultSerializerProvider, polyBase2NamedSerializers, polyBase2DefaultDeserializerProvider)
233 }
234
235 /**
236 * Adds [serializer] associated with given type [T] for contextual serialization.
237 * Throws [SerializationException] if a module already has serializer associated with the given type.
238 * To overwrite an already registered serializer, [SerializersModule.overwriteWith] can be used.
239 */
contextualnull240 public inline fun <reified T : Any> SerializersModuleBuilder.contextual(serializer: KSerializer<T>): Unit =
241 contextual(T::class, serializer)
242
243 /**
244 * Creates a builder to register subclasses of a given [baseClass] for polymorphic serialization.
245 * If [baseSerializer] is not null, registers it as a serializer for [baseClass],
246 * which is useful if the base class is serializable itself. To register subclasses,
247 * [PolymorphicModuleBuilder.subclass] builder function can be used.
248 *
249 * If a serializer already registered for the given KClass in the given scope, an [IllegalArgumentException] is thrown.
250 * To override registered serializers, combine built module with another using [SerializersModule.overwriteWith].
251 *
252 * @see PolymorphicSerializer
253 */
254 public inline fun <Base : Any> SerializersModuleBuilder.polymorphic(
255 baseClass: KClass<Base>,
256 baseSerializer: KSerializer<Base>? = null,
257 builderAction: PolymorphicModuleBuilder<Base>.() -> Unit = {}
258 ) {
259 val builder = PolymorphicModuleBuilder(baseClass, baseSerializer)
260 builder.builderAction()
261 builder.buildTo(this)
262 }
263
264 private class SerializerAlreadyRegisteredException internal constructor(msg: String) : IllegalArgumentException(msg) {
265 internal constructor(
266 baseClass: KClass<*>,
267 concreteClass: KClass<*>
268 ) : this("Serializer for $concreteClass already registered in the scope of $baseClass")
269 }
270