1 files changed, 112 insertions, 0 deletions
diff --git a/runtime/commonMain/src/kotlinx/serialization/internal/SerialClassDescImpl.kt b/runtime/commonMain/src/kotlinx/serialization/internal/SerialClassDescImpl.kt
new file mode 100644
index 00000000..5bc5b2e3
--- /dev/null
+++ b/runtime/commonMain/src/kotlinx/serialization/internal/SerialClassDescImpl.kt
@@ -0,0 +1,112 @@
+/*
+ * Copyright 2018 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@file:Suppress("OPTIONAL_DECLARATION_USAGE_IN_NON_COMMON_SOURCE")
+package kotlinx.serialization.internal
+
+import kotlinx.serialization.*
+import kotlinx.serialization.CompositeDecoder.Companion.UNKNOWN_NAME
+import kotlin.jvm.JvmOverloads
+
+class MissingDescriptorException(index: Int, origin: SerialDescriptor) :
+    SerializationException("Element descriptor at index $index has not been found in $origin")
+
+open class SerialClassDescImpl @JvmOverloads constructor(
+    override val name: String,
+    private val generatedSerializer: GeneratedSerializer<*>? = null
+) : SerialDescriptor {
+    override val kind: SerialKind get() = StructureKind.CLASS
+
+    private val names: MutableList<String> = ArrayList()
+    private val annotations: MutableList<MutableList<Annotation>> = mutableListOf()
+    private val classAnnotations: MutableList<Annotation> = mutableListOf()
+
+    private var flags = BooleanArray(4)
+
+    private val descriptors: MutableList<SerialDescriptor> = mutableListOf()
+
+    private var _indices: Map<String, Int>? = null
+    private val indices: Map<String, Int> by lazy { buildIndices() }
+
+    @JvmOverloads
+    fun addElement(name: String, isOptional: Boolean = false) {
+        names.add(name)
+        val idx = names.size - 1
+        ensureFlagsCapacity(idx)
+        flags[idx] = isOptional
+        annotations.add(mutableListOf())
+    }
+
+    fun pushAnnotation(a: Annotation) {
+        annotations.last().add(a)
+    }
+
+    fun pushDescriptor(desc: SerialDescriptor) {
+        descriptors.add(desc)
+    }
+
+    override fun getElementDescriptor(index: Int): SerialDescriptor {
+        // todo: cache
+        return generatedSerializer?.childSerializers()?.getOrNull(index)?.descriptor
+                ?: descriptors.getOrNull(index)
+                ?: throw MissingDescriptorException(index, this)
+    }
+
+    override fun isElementOptional(index: Int): Boolean {
+        return flags[index]
+    }
+
+    fun pushClassAnnotation(a: Annotation) {
+        classAnnotations.add(a)
+    }
+
+    override fun getEntityAnnotations(): List<Annotation> = classAnnotations
+    override fun getElementAnnotations(index: Int): List<Annotation> = annotations[index]
+    override val elementsCount: Int
+        get() = annotations.size
+
+    override fun getElementName(index: Int): String = names[index]
+    override fun getElementIndex(name: String): Int = indices[name] ?: UNKNOWN_NAME
+
+    private fun ensureFlagsCapacity(i: Int) {
+        if (flags.size <= i)
+            flags = flags.copyOf(flags.size * 2)
+    }
+
+    private fun buildIndices(): Map<String, Int> {
+        val indices = HashMap<String, Int>()
+        for (i in 0..names.size - 1)
+            indices.put(names[i], i)
+        return indices
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is SerialClassDescImpl) return false
+
+        if (name != other.name) return false
+        if (elementDescriptors() != other.elementDescriptors()) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = name.hashCode()
+        result = 31 * result + elementDescriptors().hashCode()
+        return result
+    }
+
+    override fun toString() = "$name$names"
+}