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package com.apollographql.apollo.api.json
import com.apollographql.apollo.api.json.BufferedSourceJsonReader.Companion.INITIAL_STACK_SIZE
import com.apollographql.apollo.api.json.MapJsonReader.Companion.buffer
import com.apollographql.apollo.api.json.internal.toDoubleExact
import com.apollographql.apollo.api.json.internal.toIntExact
import com.apollographql.apollo.api.json.internal.toLongExact
import com.apollographql.apollo.exception.JsonDataException
import kotlin.jvm.JvmOverloads
/**
* A [JsonReader] that can consumes [ApolloJsonElement] values as Json
*
* To read from a [okio.BufferedSource], see also [BufferedSourceJsonReader]
*
* @param root the root object to read from
* @param pathRoot the path root to be prefixed to the returned path when calling [getPath]. Useful for [buffer].
*/
class MapJsonReader
@JvmOverloads
constructor(
val root: Any?,
private val pathRoot: List = emptyList(),
) : JsonReader {
private var peekedToken: JsonReader.Token
/**
* Depending on what [peekedToken] is, [peekedData] can be safely cast to a Map, Entry
* or other values
*/
private var peekedData: Any? = null
/**
* Can contain either:
* - an Int representing the next index to be read in a List
* - a String representing the current key to be read in a Map
* - null if peekedToken is BEGIN_OBJECT
*/
private var path = arrayOfNulls(INITIAL_STACK_SIZE)
/**
* The current object memorized in case we need to rewind
*/
private var containerStack = arrayOfNulls>(INITIAL_STACK_SIZE)
private var iteratorStack = arrayOfNulls>(INITIAL_STACK_SIZE)
private var nameIndexStack = IntArray(INITIAL_STACK_SIZE)
private var stackSize = 0
init {
peekedToken = anyToToken(root)
peekedData = root
}
private fun anyToToken(any: Any?) = when (any) {
null -> JsonReader.Token.NULL
is List<*> -> JsonReader.Token.BEGIN_ARRAY
is Map<*, *> -> JsonReader.Token.BEGIN_OBJECT
is Int -> JsonReader.Token.NUMBER
is Long -> JsonReader.Token.LONG
is Double -> JsonReader.Token.NUMBER
is JsonNumber -> JsonReader.Token.NUMBER
is String -> JsonReader.Token.STRING
is Boolean -> JsonReader.Token.BOOLEAN
else -> JsonReader.Token.ANY
}
/**
* Updates [peekedToken] and [peekedData]
*
* Requires [iteratorStack] and [path]
*/
private fun advanceIterator() {
if (stackSize == 0) {
peekedToken = JsonReader.Token.END_DOCUMENT
return
}
val currentIterator = iteratorStack[stackSize - 1]!!
if (path[stackSize - 1] is Int) {
path[stackSize - 1] = (path[stackSize - 1] as Int) + 1
}
if (currentIterator.hasNext()) {
val next = currentIterator.next()
peekedData = next
peekedToken = when (next) {
is Map.Entry<*, *> -> JsonReader.Token.NAME
else -> anyToToken(next)
}
} else {
peekedToken = if (path[stackSize - 1] is Int) {
JsonReader.Token.END_ARRAY
} else {
JsonReader.Token.END_OBJECT
}
}
}
private fun increaseStack() {
if (stackSize == path.size) {
path = path.copyOf(path.size * 2)
containerStack = containerStack.copyOf(containerStack.size * 2)
nameIndexStack = nameIndexStack.copyOf(nameIndexStack.size * 2)
iteratorStack = iteratorStack.copyOf(iteratorStack.size * 2)
}
stackSize++
}
override fun beginArray() = apply {
if (peek() != JsonReader.Token.BEGIN_ARRAY) {
throw JsonDataException("Expected BEGIN_ARRAY but was ${peek()} at path ${getPathAsString()}")
}
val currentValue = peekedData as List
increaseStack()
path[stackSize - 1] = -1
iteratorStack[stackSize - 1] = currentValue.iterator()
advanceIterator()
}
override fun endArray() = apply {
if (peek() != JsonReader.Token.END_ARRAY) {
throw JsonDataException("Expected END_ARRAY but was ${peek()} at path ${getPathAsString()}")
}
stackSize--
iteratorStack[stackSize] = null // allow garbage collection
path[stackSize] = null // allow garbage collection
advanceIterator()
}
override fun beginObject() = apply {
if (peek() != JsonReader.Token.BEGIN_OBJECT) {
throw JsonDataException("Expected BEGIN_OBJECT but was ${peek()} at path ${getPathAsString()}")
}
increaseStack()
@Suppress("UNCHECKED_CAST")
containerStack[stackSize - 1] = peekedData as Map
rewind()
}
override fun endObject() = apply {
// Do not fail if there are trailing names in buffered readers.
// See https://github.com/apollographql/apollo-kotlin/issues/4212
// if (peek() != JsonReader.Token.END_OBJECT) {
// throw JsonDataException("Expected END_OBJECT but was ${peek()} at path ${getPathAsString()}")
// }
stackSize--
iteratorStack[stackSize] = null // allow garbage collection
path[stackSize] = null // allow garbage collection
containerStack[stackSize] = null // allow garbage collection
advanceIterator()
}
override fun hasNext(): Boolean {
return when (peek()) {
JsonReader.Token.END_OBJECT -> false
JsonReader.Token.END_ARRAY -> false
else -> true
}
}
override fun peek(): JsonReader.Token {
return peekedToken
}
override fun nextName(): String {
if (peek() != JsonReader.Token.NAME) {
throw JsonDataException("Expected NAME but was ${peek()} at path ${getPathAsString()}")
}
@Suppress("UNCHECKED_CAST")
val data = peekedData as Map.Entry
path[stackSize - 1] = data.key
peekedData = data.value
peekedToken = anyToToken(data.value)
return data.key
}
override fun nextString(): String {
// If we have a number, we convert it to a string
when (peek()) {
JsonReader.Token.STRING,
JsonReader.Token.NUMBER,
JsonReader.Token.LONG,
-> Unit
else -> {
throw JsonDataException("Expected a String but was ${peek()} at path ${getPathAsString()}")
}
}
return (peekedData!!.toString()).also {
advanceIterator()
}
}
override fun nextBoolean(): Boolean {
if (peek() != JsonReader.Token.BOOLEAN) {
throw JsonDataException("Expected BOOLEAN but was ${peek()} at path ${getPathAsString()}")
}
return (peekedData as Boolean).also {
advanceIterator()
}
}
override fun nextNull(): Nothing? {
if (peek() != JsonReader.Token.NULL) {
throw JsonDataException("Expected NULL but was ${peek()} at path ${getPathAsString()}")
}
advanceIterator()
return null
}
override fun nextDouble(): Double {
when (peek()) {
JsonReader.Token.STRING,
JsonReader.Token.NUMBER,
JsonReader.Token.LONG,
-> Unit
else -> {
throw JsonDataException("Expected a Double but was ${peek()} at path ${getPathAsString()}")
}
}
return when (val value = peekedData) {
is Int -> value.toDouble()
is Long -> value.toDoubleExact()
is Double -> value
is String -> value.toDouble()
is JsonNumber -> value.value.toDouble()
else -> error("Expected a Double but got $value instead")
}.also {
advanceIterator()
}
}
override fun nextInt(): Int {
when (peek()) {
JsonReader.Token.STRING,
JsonReader.Token.NUMBER,
JsonReader.Token.LONG,
-> Unit
else -> {
throw JsonDataException("Expected an Int but was ${peek()} at path ${getPathAsString()}")
}
}
return when (val value = peekedData) {
is Int -> value
is Long -> value.toIntExact()
is Double -> value.toIntExact()
is String -> value.toInt()
is JsonNumber -> value.value.toInt()
else -> error("Expected an Int but got $value instead")
}.also {
advanceIterator()
}
}
override fun nextLong(): Long {
when (peek()) {
JsonReader.Token.STRING,
JsonReader.Token.NUMBER,
JsonReader.Token.LONG,
-> Unit
else -> {
throw JsonDataException("Expected a Long but was ${peek()} at path ${getPathAsString()}")
}
}
return when (val value = peekedData) {
is Int -> value.toLong()
is Long -> value
is Double -> value.toLongExact()
is String -> value.toLong()
is JsonNumber -> value.value.toLong()
else -> error("Expected Int but got $value instead")
}.also {
advanceIterator()
}
}
override fun nextNumber(): JsonNumber {
when (peek()) {
JsonReader.Token.STRING,
JsonReader.Token.NUMBER,
JsonReader.Token.LONG,
-> Unit
else -> {
throw JsonDataException("Expected a Number but was ${peek()} at path ${getPathAsString()}")
}
}
return when (val value = peekedData) {
is Int, is Long, is Double -> JsonNumber(value.toString())
is String -> JsonNumber(value) // assert value is a valid number
is JsonNumber -> value
else -> error("Expected JsonNumber but got $value instead")
}.also {
advanceIterator()
}
}
fun nextValue(): Any {
val data = peekedData ?: throw JsonDataException("Expected a non-null value at path ${getPathAsString()}")
return data.also {
advanceIterator()
}
}
override fun skipValue() {
advanceIterator()
}
override fun close() {
}
private fun findName(needle: String, haystack: List): Int {
val expectedIndex = nameIndexStack[stackSize - 1]
if (expectedIndex < haystack.size && haystack[expectedIndex] == needle) {
/**
* Our guess succeeded
*
* Note that for a same object, haystack might have different size.
* For an example, for responseBased codegen and polymorphic fields, this is going
* to be called once with just ["__typename"] and then later on with ["__typename", "id", "name"]
*/
nameIndexStack[stackSize - 1] = nameIndexStack[stackSize - 1] + 1
return expectedIndex
} else {
// guess failed, go back to full search
val index = haystack.indexOf(needle)
if (index != -1) {
// reset the prediction
nameIndexStack[stackSize - 1] = index + 1
}
return index
}
}
override fun selectName(names: List): Int {
while (hasNext()) {
val name = nextName()
val index = findName(name, names)
if (index != -1) {
return index
}
// A name was present in the json but not in the expected list
skipValue()
}
return -1
}
/**
* Rewinds to the beginning of the current object.
*/
override fun rewind() {
val container = containerStack[stackSize - 1]
path[stackSize - 1] = null
iteratorStack[stackSize - 1] = container!!.iterator()
nameIndexStack[stackSize - 1] = 0
advanceIterator()
}
override fun getPath(): List {
val result = mutableListOf()
result.addAll(pathRoot)
for (index in 0 until stackSize) {
path[index]?.let { result += it }
}
return result
}
private fun getPathAsString() = getPath().joinToString(".")
companion object {
/**
* buffers the next Object. Has to be called in `BEGIN_OBJECT` position.
* The returned [MapJsonReader] can use [MapJsonReader.rewind] to read fields
* multiple times
*/
fun JsonReader.buffer(): MapJsonReader {
if (this is MapJsonReader) return this
val token = this.peek()
check(token == JsonReader.Token.BEGIN_OBJECT) {
"Failed to buffer json reader, expected `BEGIN_OBJECT` but found `$token` json token"
}
val pathRoot = getPath()
@Suppress("UNCHECKED_CAST")
val data = this.readAny() as Map
return MapJsonReader(root = data, pathRoot = pathRoot)
}
}
}
/**
* A typealias for a type-unsafe Kotlin representation of JSON. This typealias is
* mainly for internal documentation purposes and low-level manipulations and should
* generally be avoided in application code.
*
* [ApolloJsonElement] can be any of:
* - String
* - Int
* - Double
* - Long
* - JsonNumber
* - null
* - Map where values are any of these values recursively
* - List where values are any of these values recursively
* - dynamic for advanced use cases using @JsExport
*
* Anything else is undefined
*/
typealias ApolloJsonElement = Any?