1 files changed, 96 insertions, 0 deletions
diff --git a/runtime/commonMain/src/kotlinx/serialization/internal/CollectionDescriptors.kt b/runtime/commonMain/src/kotlinx/serialization/internal/CollectionDescriptors.kt
new file mode 100644
index 00000000..305b6689
--- /dev/null
+++ b/runtime/commonMain/src/kotlinx/serialization/internal/CollectionDescriptors.kt
@@ -0,0 +1,96 @@
+package kotlinx.serialization.internal
+
+import kotlinx.serialization.*
+
+
+sealed class ListLikeDescriptor(val elementDesc: SerialDescriptor) : SerialDescriptor {
+    override val kind: SerialKind get() = StructureKind.LIST
+    override val elementsCount: Int = 1
+    override fun getElementName(index: Int): String = index.toString()
+    override fun getElementIndex(name: String): Int =
+        name.toIntOrNull() ?: throw IllegalArgumentException("$name is not a valid list index")
+
+    override fun getElementDescriptor(index: Int): SerialDescriptor = elementDesc
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is ListLikeDescriptor) return false
+
+        if (elementDesc == other.elementDesc && name == other.name) return true
+
+        return false
+    }
+
+    override fun hashCode(): Int {
+        return elementDesc.hashCode() * 31 + name.hashCode()
+    }
+}
+
+sealed class MapLikeDescriptor(
+    override val name: String,
+    val keyDescriptor: SerialDescriptor,
+    val valueDescriptor: SerialDescriptor
+) : SerialDescriptor {
+    override val kind: SerialKind get() = StructureKind.MAP
+    override val elementsCount: Int = 2
+    override fun getElementName(index: Int): String = index.toString()
+    override fun getElementIndex(name: String): Int =
+        name.toIntOrNull() ?: throw IllegalArgumentException("$name is not a valid map index")
+
+    override fun getElementDescriptor(index: Int): SerialDescriptor =
+        if (index % 2 == 0) keyDescriptor else valueDescriptor
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is MapLikeDescriptor) return false
+
+        if (name != other.name) return false
+        if (keyDescriptor != other.keyDescriptor) return false
+        if (valueDescriptor != other.valueDescriptor) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = name.hashCode()
+        result = 31 * result + keyDescriptor.hashCode()
+        result = 31 * result + valueDescriptor.hashCode()
+        return result
+    }
+}
+
+internal const val ARRAY_NAME = "kotlin.Array"
+internal const val ARRAY_LIST_NAME = "kotlin.collections.ArrayList"
+internal const val LINKED_HASH_SET_NAME = "kotlin.collections.LinkedHashSet"
+internal const val HASH_SET_NAME = "kotlin.collections.HashSet"
+internal const val LINKED_HASH_MAP_NAME = "kotlin.collections.LinkedHashMap"
+internal const val HASH_MAP_NAME = "kotlin.collections.HashMap"
+
+class ArrayClassDesc(elementDesc: SerialDescriptor) : ListLikeDescriptor(elementDesc) {
+    override val name: String get() = ARRAY_NAME
+}
+
+class ArrayListClassDesc(elementDesc: SerialDescriptor) : ListLikeDescriptor(elementDesc) {
+    override val name: String get() = ARRAY_LIST_NAME
+}
+
+class NamedListClassDescriptor(override val name: String, elementDescriptor: SerialDescriptor)
+    : ListLikeDescriptor(elementDescriptor)
+
+class LinkedHashSetClassDesc(elementDesc: SerialDescriptor) : ListLikeDescriptor(elementDesc) {
+    override val name: String get() = LINKED_HASH_SET_NAME
+}
+
+class HashSetClassDesc(elementDesc: SerialDescriptor) : ListLikeDescriptor(elementDesc) {
+    override val name: String get() = HASH_SET_NAME
+}
+
+// TODO revisit this whole hierarchy
+class NamedMapClassDescriptor(name: String, keyDescriptor: SerialDescriptor, valueDescriptor: SerialDescriptor) :
+    MapLikeDescriptor(name, keyDescriptor, valueDescriptor)
+
+class LinkedHashMapClassDesc(keyDesc: SerialDescriptor, valueDesc: SerialDescriptor) :
+    MapLikeDescriptor(LINKED_HASH_MAP_NAME, keyDesc, valueDesc)
+
+class HashMapClassDesc(keyDesc: SerialDescriptor, valueDesc: SerialDescriptor) :
+    MapLikeDescriptor(HASH_MAP_NAME, keyDesc, valueDesc)