org.jetbrains.kotlin.backend.common.CodegenUtilKt.kt Maven / Gradle / Ivy

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/*
 * Copyright 2010-2015 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.
 */

package org.jetbrains.kotlin.backend.common

import org.jetbrains.kotlin.descriptors.CallableDescriptor
import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
import org.jetbrains.kotlin.descriptors.ClassDescriptor
import org.jetbrains.kotlin.incremental.components.NoLookupLocation
import org.jetbrains.kotlin.resolve.DescriptorUtils
import org.jetbrains.kotlin.resolve.MemberComparator
import org.jetbrains.kotlin.types.KotlinType
import org.jetbrains.kotlin.types.isDynamic
import org.jetbrains.kotlin.utils.keysToMapExceptNulls
import java.util.Comparator

object CodegenUtilKt {

    // class Foo : Bar by baz
    //   descriptor = Foo
    //   toInterface = Bar
    //   delegateExpressionType = typeof(baz)
    // return Map
    @JvmStatic fun getDelegates(
            descriptor: ClassDescriptor,
            toInterface: ClassDescriptor,
            delegateExpressionType: KotlinType? = null
    ): Map {
        if (delegateExpressionType?.isDynamic() ?: false) return mapOf();

        return descriptor.defaultType.memberScope.getContributedDescriptors().asSequence()
            .filterIsInstance()
            .filter { it.kind == CallableMemberDescriptor.Kind.DELEGATION }
            .asIterable()
            .sortedWith(MemberComparator.INSTANCE)
            .keysToMapExceptNulls {
                delegatingMember ->

                val actualDelegates = DescriptorUtils.getAllOverriddenDescriptors(delegatingMember)
                        .mapNotNull {
                            overriddenDescriptor ->
                            if (overriddenDescriptor.containingDeclaration == toInterface) {
                                val scope = (delegateExpressionType ?: toInterface.defaultType).memberScope
                                val name = overriddenDescriptor.name

                                // this is the actual member of delegateExpressionType that we are delegating to
                                (scope.getContributedFunctions(name, NoLookupLocation.FROM_BACKEND) + scope.getContributedVariables(name, NoLookupLocation.FROM_BACKEND))
                                        .firstOrNull {
                                            (listOf(it) + DescriptorUtils.getAllOverriddenDescriptors(it))
                                                    .map { it.original }
                                                    .contains(overriddenDescriptor.original)
                                        }
                            }
                            else null
                        }
                assert(actualDelegates.size <= 1) { "Many delegates found for $delegatingMember: $actualDelegates" }

                actualDelegates.firstOrNull()
            }
    }
}