Add support for Draft 2020-12 (#36)

Resolves #35

Author: OptimumCode

api/json-schema-validator.api

@@ -63,6 +63,7 @@ public final class io/github/optimumcode/json/schema/JsonSchemaStream {
 public final class io/github/optimumcode/json/schema/SchemaType : java/lang/Enum {
 	public static final field Companion Lio/github/optimumcode/json/schema/SchemaType$Companion;
 	public static final field DRAFT_2019_09 Lio/github/optimumcode/json/schema/SchemaType;
+	public static final field DRAFT_2020_12 Lio/github/optimumcode/json/schema/SchemaType;
 	public static final field DRAFT_7 Lio/github/optimumcode/json/schema/SchemaType;
 	public static final fun find (Ljava/lang/String;)Lio/github/optimumcode/json/schema/SchemaType;
 	public static fun valueOf (Ljava/lang/String;)Lio/github/optimumcode/json/schema/SchemaType;

src/commonMain/kotlin/io/github/optimumcode/json/pointer/internal/extensions.kt

@@ -0,0 +1,35 @@
+@file:Suppress("ktlint:standard:filename")
+
+package io.github.optimumcode.json.pointer.internal
+
+import io.github.optimumcode.json.pointer.EmptyPointer
+import io.github.optimumcode.json.pointer.JsonPointer
+import io.github.optimumcode.json.pointer.SegmentPointer
+
+internal val JsonPointer.length: Int
+  get() {
+    if (this is EmptyPointer) {
+      return 0
+    }
+    var length = 0
+    var segment: JsonPointer? = this
+    while (segment != null) {
+      if (segment is SegmentPointer) {
+        length += 1
+      }
+      segment = segment.next
+    }
+    return length
+  }
+
+internal fun JsonPointer.dropLast(): JsonPointer? {
+  if (this is EmptyPointer) {
+    return null
+  }
+  val fullPath = toString()
+  val lastPathPart = fullPath.lastIndexOf('/')
+  if (lastPathPart == 0) {
+    return EmptyPointer
+  }
+  return JsonPointer.compile(fullPath.substring(0, lastPathPart))
+}

src/commonMain/kotlin/io/github/optimumcode/json/schema/SchemaType.kt

@@ -3,6 +3,7 @@ package io.github.optimumcode.json.schema
 import com.eygraber.uri.Uri
 import io.github.optimumcode.json.schema.internal.SchemaLoaderConfig
 import io.github.optimumcode.json.schema.internal.config.Draft201909SchemaLoaderConfig
+import io.github.optimumcode.json.schema.internal.config.Draft202012SchemaLoaderConfig
 import io.github.optimumcode.json.schema.internal.config.Draft7SchemaLoaderConfig
 import kotlin.jvm.JvmStatic
 
@@ -12,6 +13,7 @@ public enum class SchemaType(
 ) {
   DRAFT_7(Uri.parse("http://json-schema.org/draft-07/schema"), Draft7SchemaLoaderConfig),
   DRAFT_2019_09(Uri.parse("https://json-schema.org/draft/2019-09/schema"), Draft201909SchemaLoaderConfig),
+  DRAFT_2020_12(Uri.parse("https://json-schema.org/draft/2020-12/schema"), Draft202012SchemaLoaderConfig),
   ;
 
   public companion object {

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/AssertionContext.kt

@@ -3,10 +3,14 @@ package io.github.optimumcode.json.schema.internal
 import io.github.optimumcode.json.pointer.JsonPointer
 import io.github.optimumcode.json.pointer.div
 import io.github.optimumcode.json.pointer.get
+import io.github.optimumcode.json.pointer.internal.dropLast
+import io.github.optimumcode.json.pointer.internal.length
+import io.github.optimumcode.json.pointer.startsWith
 import kotlin.jvm.JvmStatic
 import kotlin.reflect.KClass
 import kotlin.reflect.cast
 
+@Suppress("detekt:TooManyFunctions")
 internal interface AssertionContext {
   val objectPath: JsonPointer
   fun <T : Any> annotate(key: AnnotationKey<T>, value: T)
@@ -16,6 +20,8 @@ internal interface AssertionContext {
   fun at(property: String): AssertionContext
   fun resolveRef(refId: RefId): Pair<JsonPointer, JsonSchemaAssertion>
 
+  fun resolveDynamicRef(refId: RefId, refPath: JsonPointer): Pair<JsonPointer, JsonSchemaAssertion>
+
   /**
    * Discards collected annotations
    */
@@ -53,6 +59,10 @@ internal interface AssertionContext {
    * Returns recursive root for current state of the validation
    */
   fun getRecursiveRoot(): JsonSchemaAssertion?
+
+  fun pushSchemaPath(path: JsonPointer)
+
+  fun popSchemaPath()
 }
 
 internal fun interface Aggregator<T : Any> {
@@ -108,11 +118,13 @@ internal class AnnotationKey<T : Any> private constructor(
   }
 }
 
+@Suppress("detekt:TooManyFunctions")
 internal data class DefaultAssertionContext(
   override val objectPath: JsonPointer,
   private val references: Map<RefId, AssertionWithPath>,
   private val parent: DefaultAssertionContext? = null,
   private var recursiveRoot: JsonSchemaAssertion? = null,
+  private val schemaPathsStack: ArrayDeque<JsonPointer> = ArrayDeque(),
 ) : AssertionContext {
   private lateinit var _annotations: MutableMap<AnnotationKey<*>, Any>
   private lateinit var _aggregatedAnnotations: MutableMap<AnnotationKey<*>, Any>
@@ -156,6 +168,44 @@ internal data class DefaultAssertionContext(
     return resolvedRef.schemaPath to resolvedRef.assertion
   }
 
+  override fun resolveDynamicRef(refId: RefId, refPath: JsonPointer): Pair<JsonPointer, JsonSchemaAssertion> {
+    val originalRef = requireNotNull(references[refId]) { "$refId is not found" }
+    if (!originalRef.dynamic) {
+      return originalRef.schemaPath to originalRef.assertion
+    }
+    val fragment = refId.fragment
+    val possibleDynamicRefs: MutableList<AssertionWithPath> = references.asSequence()
+      .filter { (id, link) ->
+        link.dynamic && id.fragment == fragment && id != refId
+      }.map { it.value }.toMutableList()
+    possibleDynamicRefs.sortBy { it.schemaPath.length }
+
+    val resolvedDynamicRef = findMostOuterRef(possibleDynamicRefs)
+      // If no outer anchor found use the original ref
+      ?: possibleDynamicRefs.firstOrNull()
+      ?: originalRef
+    return resolvedDynamicRef.schemaPath to resolvedDynamicRef.assertion
+  }
+
+  @Suppress("detekt:NestedBlockDepth")
+  private fun findMostOuterRef(possibleRefs: List<AssertionWithPath>): AssertionWithPath? {
+    // Try to find the most outer anchor to use
+    // Check every schema in the current chain
+    // If not matches - take the most outer by location
+    for (schemaPath in schemaPathsStack) {
+      var currPath: JsonPointer = schemaPath
+      while (currPath != JsonPointer.ROOT) {
+        for (dynamicRef in possibleRefs) {
+          if (dynamicRef.schemaPath.startsWith(currPath)) {
+            return dynamicRef
+          }
+        }
+        currPath = currPath.dropLast() ?: break
+      }
+    }
+    return null
+  }
+
   override fun resetAnnotations() {
     if (::_annotations.isInitialized && _annotations.isNotEmpty()) {
       _annotations.clear()
@@ -198,6 +248,14 @@ internal data class DefaultAssertionContext(
     return recursiveRoot
   }
 
+  override fun pushSchemaPath(path: JsonPointer) {
+    schemaPathsStack.addLast(path)
+  }
+
+  override fun popSchemaPath() {
+    schemaPathsStack.removeLast()
+  }
+
   private inline fun aggregateAnnotations(
     source: MutableMap<AnnotationKey<*>, Any>,
     destination: () -> MutableMap<AnnotationKey<*>, Any>,

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/JsonSchemaRoot.kt

@@ -1,9 +1,11 @@
 package io.github.optimumcode.json.schema.internal
 
+import io.github.optimumcode.json.pointer.JsonPointer
 import io.github.optimumcode.json.schema.ErrorCollector
 import kotlinx.serialization.json.JsonElement
 
 internal class JsonSchemaRoot(
+  private val schemaPath: JsonPointer,
   private val assertions: Collection<JsonSchemaAssertion>,
   private val canBeReferencedRecursively: Boolean,
 ) : JsonSchemaAssertion {
@@ -15,10 +17,12 @@ internal class JsonSchemaRoot(
       context.resetRecursiveRoot()
     }
     var result = true
+    context.pushSchemaPath(schemaPath)
     assertions.forEach {
       val valid = it.validate(element, context, errorCollector)
       result = result and valid
     }
+    context.popSchemaPath()
     // According to spec the annotations should not be applied if element does not match the schema
     if (result) {
       context.applyAnnotations()

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/KeyWord.kt

@@ -16,6 +16,11 @@ internal enum class KeyWord {
    */
   ANCHOR,
 
+  /**
+   * Keyword that is used to define dynamic anchor to be referenced by dynamic refs
+   */
+  DYNAMIC_ANCHOR,
+
   /**
    * Keyword for definitions in current JSON schema
    */

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/RecursiveRefSchemaAssertion.kt

@@ -15,10 +15,8 @@ internal class RecursiveRefSchemaAssertion(
 
   override fun validate(element: JsonElement, context: AssertionContext, errorCollector: ErrorCollector): Boolean {
     return context.getRecursiveRoot()?.validate(element, context, errorCollector) ?: run {
-      // This part is pretty similar to RefSchemaAssertion,
-      // but I am not sure if it should be extracted into a base class for now
       if (!::refAssertion.isInitialized) {
-        val resolved = context.resolveRef(refId)
+        val resolved = context.resolveDynamicRef(refId, basePath)
         refIdPath = resolved.first
         refAssertion = resolved.second
       }

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/SchemaLoader.kt

@@ -33,9 +33,13 @@ internal class SchemaLoader {
       context.usedRef,
     )
     val usedRefs = context.usedRef.map { it.refId }.toSet()
+    val dynamicRefs = context.references.asSequence()
+      .filter { it.value.dynamic }
+      .map { it.key }
+      .toSet()
     // pre-filter references to get rid of unused references
     val usedReferencesWithPath: Map<RefId, AssertionWithPath> = context.references.asSequence()
-      .filter { it.key in usedRefs }
+      .filter { it.key in usedRefs || it.key in dynamicRefs }
       .associate { it.key to it.value }
     return JsonSchema(schemaAssertion, usedReferencesWithPath)
   }
@@ -121,7 +125,11 @@ private fun loadSchema(
         null
       }
       if (refAssertion != null && !referenceFactory.allowOverriding) {
-        JsonSchemaRoot(listOf(refAssertion), contextWithAdditionalID.recursiveResolution)
+        JsonSchemaRoot(
+          contextWithAdditionalID.schemaPath,
+          listOf(refAssertion),
+          contextWithAdditionalID.recursiveResolution,
+        )
       } else {
         loadJsonSchemaRoot(contextWithAdditionalID, schemaDefinition, refAssertion)
       }
@@ -131,11 +139,29 @@ private fun loadSchema(
   }.apply {
     loadDefinitions(schemaDefinition, contextWithAdditionalID)
     context.register(additionalId, this)
-    val anchorProperty: String? = context.config.keywordResolver.resolve(KeyWord.ANCHOR)
-    if (anchorProperty != null && schemaDefinition is JsonObject) {
-      schemaDefinition.getString(anchorProperty)?.also {
-        contextWithAdditionalID.registerByAnchor(it, this)
-      }
+    registerWithAnchor(
+      context.config.keywordResolver.resolve(KeyWord.ANCHOR),
+      schemaDefinition,
+      contextWithAdditionalID,
+    )
+    registerWithAnchor(
+      context.config.keywordResolver.resolve(KeyWord.DYNAMIC_ANCHOR),
+      schemaDefinition,
+      contextWithAdditionalID,
+      dynamic = true,
+    )
+  }
+}
+
+private fun JsonSchemaAssertion.registerWithAnchor(
+  anchorProperty: String?,
+  schemaDefinition: JsonElement,
+  contextWithAdditionalID: DefaultLoadingContext,
+  dynamic: Boolean = false,
+) {
+  if (anchorProperty != null && schemaDefinition is JsonObject) {
+    schemaDefinition.getString(anchorProperty)?.also {
+      contextWithAdditionalID.registerByAnchor(it, this, dynamic)
     }
   }
 }
@@ -158,6 +184,7 @@ private fun loadJsonSchemaRoot(
     addAll(assertions)
   }
   return JsonSchemaRoot(
+    context.schemaPath,
     result,
     context.recursiveResolution,
   )
@@ -187,6 +214,7 @@ internal data class IdWithLocation(
 internal data class AssertionWithPath(
   val assertion: JsonSchemaAssertion,
   val schemaPath: JsonPointer,
+  val dynamic: Boolean,
 )
 
 private data class DefaultLoadingContext(
@@ -213,9 +241,9 @@ private data class DefaultLoadingContext(
       (element is JsonPrimitive && element.booleanOrNull != null)
     )
 
-  fun register(id: Uri?, assertion: JsonSchemaAssertion) {
+  fun register(id: Uri?, assertion: JsonSchemaAssertion, dynamic: Boolean = false) {
     if (id != null) {
-      registerById(id, assertion)
+      registerById(id, assertion, dynamic)
     }
     for ((baseId, location) in additionalIDs) {
       val relativePointer = location.relative(schemaPath)
@@ -227,18 +255,18 @@ private data class DefaultLoadingContext(
         // and we register it using Empty pointer
         continue
       }
-      register(referenceId, assertion)
+      register(referenceId, assertion, dynamic = false)
     }
   }
 
   /**
    * [anchor] is a plain text that will be transformed into a URI fragment
    * It must match [ANCHOR_REGEX] otherwise [IllegalArgumentException] will be thrown
    */
-  fun registerByAnchor(anchor: String, assertion: JsonSchemaAssertion) {
+  fun registerByAnchor(anchor: String, assertion: JsonSchemaAssertion, dynamic: Boolean) {
     require(ANCHOR_REGEX.matches(anchor)) { "$anchor must match the format ${ANCHOR_REGEX.pattern}" }
     val refId = additionalIDs.last().id.buildUpon().fragment(anchor).buildRefId()
-    register(refId, assertion)
+    register(refId, assertion, dynamic)
   }
 
   fun addId(additionalId: Uri): DefaultLoadingContext {
@@ -289,21 +317,24 @@ private data class DefaultLoadingContext(
   private fun registerById(
     id: Uri,
     assertion: JsonSchemaAssertion,
+    dynamic: Boolean,
   ) {
     when {
-      id.isAbsolute -> register(id.buildRefId(), assertion) // register JSON schema by absolute URI
+      id.isAbsolute -> register(id.buildRefId(), assertion, dynamic) // register JSON schema by absolute URI
       id.isRelative ->
         when {
           !id.path.isNullOrBlank() -> register(
             // register JSON schema by related path
             additionalIDs.resolvePath(id.path).buildRefId(),
             assertion,
+            dynamic,
           )
 
           !id.fragment.isNullOrBlank() -> register(
             // register JSON schema by fragment
             additionalIDs.last().id.buildUpon().encodedFragment(id.fragment).buildRefId(),
             assertion,
+            dynamic,
           )
         }
     }
@@ -312,8 +343,9 @@ private data class DefaultLoadingContext(
   private fun register(
     referenceId: RefId,
     assertion: JsonSchemaAssertion,
+    dynamic: Boolean,
   ) {
-    references.put(referenceId, AssertionWithPath(assertion, schemaPath))?.apply {
+    references.put(referenceId, AssertionWithPath(assertion, schemaPath, dynamic))?.apply {
       throw IllegalStateException("duplicated definition $referenceId")
     }
   }

src/commonMain/kotlin/io/github/optimumcode/json/schema/internal/SchemaLoaderConfig.kt

@@ -45,7 +45,6 @@ internal interface ReferenceFactory {
     data class Recursive(
       val property: String,
       val refId: RefId,
-      val relativePath: String,
     ) : RefHolder()
   }
 }