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Kotlin multiplatform serialization runtime library
/*
* Copyright 2017-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
*/
@file:Suppress("unused")
package kotlinx.serialization.json
import kotlinx.serialization.*
import kotlinx.serialization.builtins.serializer
import kotlinx.serialization.descriptors.SerialDescriptor
import kotlinx.serialization.internal.InlinePrimitiveDescriptor
import kotlinx.serialization.json.internal.*
/**
* Class representing single JSON element.
* Can be [JsonPrimitive], [JsonArray] or [JsonObject].
*
* [JsonElement.toString] properly prints JSON tree as valid JSON, taking into account quoted values and primitives.
* Whole hierarchy is serializable, but only when used with [Json] as [JsonElement] is purely JSON-specific structure
* which has a meaningful schemaless semantics only for JSON.
*
* The whole hierarchy is [serializable][Serializable] only by [Json] format.
*/
@Serializable(JsonElementSerializer::class)
public sealed class JsonElement
/**
* Class representing JSON primitive value.
* JSON primitives include numbers, strings, booleans and special null value [JsonNull].
*/
@Serializable(JsonPrimitiveSerializer::class)
public sealed class JsonPrimitive : JsonElement() {
/**
* Indicates whether the primitive was explicitly constructed from [String] and
* whether it should be serialized as one. E.g. `JsonPrimitive("42")` is represented
* by a string, while `JsonPrimitive(42)` is not.
* These primitives will be serialized as `42` and `"42"` respectively.
*/
public abstract val isString: Boolean
/**
* Content of given element without quotes. For [JsonNull], this method returns a "null" string.
* [JsonPrimitive.contentOrNull] should be used for [JsonNull] to get a `null`.
*/
public abstract val content: String
public override fun toString(): String = content
}
/** Creates a [JsonPrimitive] from the given boolean. */
public fun JsonPrimitive(value: Boolean?): JsonPrimitive {
if (value == null) return JsonNull
return JsonLiteral(value, isString = false)
}
/** Creates a [JsonPrimitive] from the given number. */
public fun JsonPrimitive(value: Number?): JsonPrimitive {
if (value == null) return JsonNull
return JsonLiteral(value, isString = false)
}
/**
* Creates a numeric [JsonPrimitive] from the given [UByte].
*
* The value will be encoded as a JSON number.
*/
@ExperimentalSerializationApi
public fun JsonPrimitive(value: UByte): JsonPrimitive = JsonPrimitive(value.toULong())
/**
* Creates a numeric [JsonPrimitive] from the given [UShort].
*
* The value will be encoded as a JSON number.
*/
@ExperimentalSerializationApi
public fun JsonPrimitive(value: UShort): JsonPrimitive = JsonPrimitive(value.toULong())
/**
* Creates a numeric [JsonPrimitive] from the given [UInt].
*
* The value will be encoded as a JSON number.
*/
@ExperimentalSerializationApi
public fun JsonPrimitive(value: UInt): JsonPrimitive = JsonPrimitive(value.toULong())
/**
* Creates a numeric [JsonPrimitive] from the given [ULong].
*
* The value will be encoded as a JSON number.
*/
@SuppressAnimalSniffer // Long.toUnsignedString(long)
@ExperimentalSerializationApi
public fun JsonPrimitive(value: ULong): JsonPrimitive = JsonUnquotedLiteral(value.toString())
/** Creates a [JsonPrimitive] from the given string. */
public fun JsonPrimitive(value: String?): JsonPrimitive {
if (value == null) return JsonNull
return JsonLiteral(value, isString = true)
}
/** Creates [JsonNull]. */
@ExperimentalSerializationApi
@Suppress("FunctionName", "UNUSED_PARAMETER") // allows to call `JsonPrimitive(null)`
public fun JsonPrimitive(value: Nothing?): JsonNull = JsonNull
/**
* Creates a [JsonPrimitive] from the given string, without surrounding it in quotes.
*
* This function is provided for encoding raw JSON values that cannot be encoded using the [JsonPrimitive] functions.
* For example,
*
* * precise numeric values (avoiding floating-point precision errors associated with [Double] and [Float]),
* * large numbers,
* * or complex JSON objects.
*
* Be aware that it is possible to create invalid JSON using this function.
*
* Creating a literal unquoted value of `null` (as in, `value == "null"`) is forbidden. If you want to create
* JSON null literal, use [JsonNull] object, otherwise, use [JsonPrimitive].
*
* @see JsonPrimitive is the preferred method for encoding JSON primitives.
* @throws JsonEncodingException if `value == "null"`
*/
@ExperimentalSerializationApi
@Suppress("FunctionName")
public fun JsonUnquotedLiteral(value: String?): JsonPrimitive {
return when (value) {
null -> JsonNull
JsonNull.content -> throw JsonEncodingException("Creating a literal unquoted value of 'null' is forbidden. If you want to create JSON null literal, use JsonNull object, otherwise, use JsonPrimitive")
else -> JsonLiteral(value, isString = false, coerceToInlineType = jsonUnquotedLiteralDescriptor)
}
}
/** Used as a marker to indicate during encoding that the [JsonEncoder] should use `encodeInline()` */
internal val jsonUnquotedLiteralDescriptor: SerialDescriptor =
InlinePrimitiveDescriptor("kotlinx.serialization.json.JsonUnquotedLiteral", String.serializer())
// JsonLiteral is deprecated for public use and no longer available. Please use JsonPrimitive instead
internal class JsonLiteral internal constructor(
body: Any,
public override val isString: Boolean,
internal val coerceToInlineType: SerialDescriptor? = null,
) : JsonPrimitive() {
public override val content: String = body.toString()
init {
if (coerceToInlineType != null) require(coerceToInlineType.isInline)
}
public override fun toString(): String =
if (isString) buildString { printQuoted(content) }
else content
// Compare by `content` and `isString`, because body can be kotlin.Long=42 or kotlin.String="42"
public override fun equals(other: Any?): Boolean {
if (this === other) return true
if (other == null || this::class != other::class) return false
other as JsonLiteral
if (isString != other.isString) return false
if (content != other.content) return false
return true
}
@SuppressAnimalSniffer // Boolean.hashCode(boolean)
public override fun hashCode(): Int {
var result = isString.hashCode()
result = 31 * result + content.hashCode()
return result
}
}
/**
* Class representing JSON `null` value
*/
@Serializable(JsonNullSerializer::class)
public object JsonNull : JsonPrimitive() {
override val isString: Boolean get() = false
override val content: String = "null"
}
/**
* Class representing JSON object, consisting of name-value pairs, where value is arbitrary [JsonElement]
*
* Since this class also implements [Map] interface, you can use
* traditional methods like [Map.get] or [Map.getValue] to obtain Json elements.
*/
@Serializable(JsonObjectSerializer::class)
public class JsonObject(
private val content: Map
) : JsonElement(), Map by content {
public override fun equals(other: Any?): Boolean = content == other
public override fun hashCode(): Int = content.hashCode()
public override fun toString(): String {
return content.entries.joinToString(
separator = ",",
prefix = "{",
postfix = "}",
transform = { (k, v) ->
buildString {
printQuoted(k)
append(':')
append(v)
}
}
)
}
}
/**
* Class representing JSON array, consisting of indexed values, where value is arbitrary [JsonElement]
*
* Since this class also implements [List] interface, you can use
* traditional methods like [List.get] or [List.getOrNull] to obtain Json elements.
*/
@Serializable(JsonArraySerializer::class)
public class JsonArray(private val content: List) : JsonElement(), List by content {
public override fun equals(other: Any?): Boolean = content == other
public override fun hashCode(): Int = content.hashCode()
public override fun toString(): String = content.joinToString(prefix = "[", postfix = "]", separator = ",")
}
/**
* Convenience method to get current element as [JsonPrimitive]
* @throws IllegalArgumentException if current element is not a [JsonPrimitive]
*/
public val JsonElement.jsonPrimitive: JsonPrimitive
get() = this as? JsonPrimitive ?: error("JsonPrimitive")
/**
* Convenience method to get current element as [JsonObject]
* @throws IllegalArgumentException if current element is not a [JsonObject]
*/
public val JsonElement.jsonObject: JsonObject
get() = this as? JsonObject ?: error("JsonObject")
/**
* Convenience method to get current element as [JsonArray]
* @throws IllegalArgumentException if current element is not a [JsonArray]
*/
public val JsonElement.jsonArray: JsonArray
get() = this as? JsonArray ?: error("JsonArray")
/**
* Convenience method to get current element as [JsonNull]
* @throws IllegalArgumentException if current element is not a [JsonNull]
*/
public val JsonElement.jsonNull: JsonNull
get() = this as? JsonNull ?: error("JsonNull")
/**
* Returns content of the current element as int
* @throws NumberFormatException if current element is not a valid representation of number
*/
public val JsonPrimitive.int: Int
get() {
val result = mapExceptions { StringJsonLexer(content).consumeNumericLiteral() }
if (result !in Int.MIN_VALUE..Int.MAX_VALUE) throw NumberFormatException("$content is not an Int")
return result.toInt()
}
/**
* Returns content of the current element as int or `null` if current element is not a valid representation of number
*/
public val JsonPrimitive.intOrNull: Int?
get() {
val result = mapExceptionsToNull { StringJsonLexer(content).consumeNumericLiteral() } ?: return null
if (result !in Int.MIN_VALUE..Int.MAX_VALUE) return null
return result.toInt()
}
/**
* Returns content of current element as long
* @throws NumberFormatException if current element is not a valid representation of number
*/
public val JsonPrimitive.long: Long get() = mapExceptions { StringJsonLexer(content).consumeNumericLiteral() }
/**
* Returns content of current element as long or `null` if current element is not a valid representation of number
*/
public val JsonPrimitive.longOrNull: Long?
get() =
mapExceptionsToNull { StringJsonLexer(content).consumeNumericLiteral() }
/**
* Returns content of current element as double
* @throws NumberFormatException if current element is not a valid representation of number
*/
public val JsonPrimitive.double: Double get() = content.toDouble()
/**
* Returns content of current element as double or `null` if current element is not a valid representation of number
*/
public val JsonPrimitive.doubleOrNull: Double? get() = content.toDoubleOrNull()
/**
* Returns content of current element as float
* @throws NumberFormatException if current element is not a valid representation of number
*/
public val JsonPrimitive.float: Float get() = content.toFloat()
/**
* Returns content of current element as float or `null` if current element is not a valid representation of number
*/
public val JsonPrimitive.floatOrNull: Float? get() = content.toFloatOrNull()
/**
* Returns content of current element as boolean
* @throws IllegalStateException if current element doesn't represent boolean
*/
public val JsonPrimitive.boolean: Boolean
get() = content.toBooleanStrictOrNull() ?: throw IllegalStateException("$this does not represent a Boolean")
/**
* Returns content of current element as boolean or `null` if current element is not a valid representation of boolean
*/
public val JsonPrimitive.booleanOrNull: Boolean? get() = content.toBooleanStrictOrNull()
/**
* Content of the given element without quotes or `null` if current element is [JsonNull]
*/
public val JsonPrimitive.contentOrNull: String? get() = if (this is JsonNull) null else content
private fun JsonElement.error(element: String): Nothing =
throw IllegalArgumentException("Element ${this::class} is not a $element")
private inline fun mapExceptionsToNull(f: () -> T): T? {
return try {
f()
} catch (e: JsonDecodingException) {
null
}
}
private inline fun mapExceptions(f: () -> T): T {
return try {
f()
} catch (e: JsonDecodingException) {
throw NumberFormatException(e.message)
}
}
@PublishedApi
internal fun unexpectedJson(key: String, expected: String): Nothing =
throw IllegalArgumentException("Element $key is not a $expected")