Reflection: add KClassifier.createType

#KT-8998 In Progress
2016-07-12 16:38:45 +03:00
parent 153e837a84
commit 1edf3c7809
8 changed files with 301 additions and 0 deletions
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2010-2016 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:JvmName("KClassifiers")
+package kotlin.reflect
+
+import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.types.*
+import kotlin.reflect.jvm.internal.KClassImpl
+import kotlin.reflect.jvm.internal.KClassifierImpl
+import kotlin.reflect.jvm.internal.KTypeImpl
+import kotlin.reflect.jvm.internal.KTypeParameterImpl
+
+/**
+ * Creates a [KType] instance with the given classifier, type arguments, nullability and annotations.
+ * If the number of passed type arguments is not equal to the total number of type parameters of a classifier,
+ * an exception is thrown. If any of the arguments does not satisfy the bounds of the corresponding type parameter,
+ * an exception is thrown.
+ *
+ * For classifiers representing type parameters, the type argument list must always be empty.
+ * For classes, the type argument list should contain arguments for the type parameters of the class. If the class is `inner`,
+ * the list should follow with arguments for the type parameters of its outer class, and so forth until a class is
+ * not `inner`, or is declared on the top level.
+ */
+fun KClassifier.createType(
+        arguments: List<KTypeProjection> = emptyList(),
+        nullable: Boolean = false,
+        annotations: List<Annotation> = emptyList()
+): KType {
+    val descriptor = (this as? KClassifierImpl)?.descriptor
+                     ?: throw KotlinReflectionInternalError("Cannot create type for an unsupported classifier: $this (${this.javaClass})")
+
+    val typeConstructor = descriptor.typeConstructor
+    val parameters = typeConstructor.parameters
+    if (parameters.size != arguments.size) {
+        throw IllegalArgumentException("Class declares ${parameters.size} type parameters, but ${arguments.size} were provided.")
+    }
+
+    // TODO: throw exception if argument does not satisfy bounds
+
+    val typeAnnotations =
+            if (annotations.isEmpty()) Annotations.EMPTY
+            else Annotations.EMPTY // TODO: support type annotations
+
+    val kotlinType = createKotlinType(typeAnnotations, typeConstructor, arguments, nullable)
+
+    return KTypeImpl(kotlinType) {
+        TODO("Java type is not yet supported for types created with createType (classifier = $this)")
+    }
+}
+
+private fun createKotlinType(
+        typeAnnotations: Annotations, typeConstructor: TypeConstructor, arguments: List<KTypeProjection>, nullable: Boolean
+): SimpleType {
+    val parameters = typeConstructor.parameters
+    return KotlinTypeFactory.simpleType(typeAnnotations, typeConstructor, arguments.mapIndexed { index, typeProjection ->
+        val type = (typeProjection.type as KTypeImpl?)?.type
+        when (typeProjection) {
+            is KTypeProjection.Invariant -> TypeProjectionImpl(Variance.INVARIANT, type!!)
+            is KTypeProjection.In -> TypeProjectionImpl(Variance.IN_VARIANCE, type!!)
+            is KTypeProjection.Out -> TypeProjectionImpl(Variance.OUT_VARIANCE, type!!)
+            is KTypeProjection.Star -> StarProjectionImpl(parameters[index])
+        }
+    }, nullable)
+}