org.jetbrains.kotlin.resolve.findLoopsInSupertypes.kt Maven / Gradle / Ivy
/*
* 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.
*/
@file:JvmName("FindLoopsInSupertypes")
package org.jetbrains.kotlin.resolve
import org.jetbrains.kotlin.descriptors.SupertypeLoopChecker
import org.jetbrains.kotlin.types.KotlinType
import org.jetbrains.kotlin.types.TypeConstructor
import org.jetbrains.kotlin.utils.DFS
import org.jetbrains.kotlin.utils.SmartList
class SupertypeLoopCheckerImpl : SupertypeLoopChecker {
override fun findLoopsInSupertypesAndDisconnect(
currentTypeConstructor: TypeConstructor,
superTypes: Collection,
neighbors: (TypeConstructor) -> Iterable,
reportLoop: (KotlinType) -> Unit
): Collection {
val graph = DFS.Neighbors { node -> neighbors(node).map { it.constructor } }
val superTypesToRemove = SmartList()
for (superType in superTypes) {
if (isReachable(superType.constructor, currentTypeConstructor, graph)) {
superTypesToRemove.add(superType)
reportLoop(superType)
}
}
return if (superTypesToRemove.isEmpty()) superTypes else superTypes - superTypesToRemove
}
}
private fun isReachable(
from: TypeConstructor, to: TypeConstructor,
neighbors: DFS.Neighbors
): Boolean {
var result = false
DFS.dfs(listOf(from), neighbors, DFS.VisitedWithSet(), object : DFS.AbstractNodeHandler() {
override fun beforeChildren(current: TypeConstructor): Boolean {
if (current == to) {
result = true
return false
}
return true
}
override fun result() = Unit
})
return result
}