org.jetbrains.kotlin.cfg.UnreachableCode.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.
*/
package org.jetbrains.kotlin.cfg
import com.intellij.openapi.util.TextRange
import com.intellij.psi.PsiComment
import com.intellij.psi.PsiElement
import com.intellij.psi.PsiElementVisitor
import com.intellij.psi.PsiWhiteSpace
import com.intellij.psi.util.PsiTreeUtil
import org.jetbrains.kotlin.lexer.KtTokens
import org.jetbrains.kotlin.psi.KtElement
import org.jetbrains.kotlin.psi.KtPsiUtil
import java.util.*
interface UnreachableCode {
val elements: Set
fun getUnreachableTextRanges(element: KtElement): List
}
class UnreachableCodeImpl(
private val reachableElements: Set,
private val unreachableElements: Set
) : UnreachableCode {
// This is needed in order to highlight only '1 < 2' and not '1', '<' and '2' as well
override val elements = KtPsiUtil.findRootExpressions(unreachableElements)
override fun getUnreachableTextRanges(element: KtElement): List {
return if (element.hasChildrenInSet(reachableElements)) {
with (element.getLeavesOrReachableChildren().removeReachableElementsWithMeaninglessSiblings().mergeAdjacentTextRanges()) {
if (isNotEmpty()) this
// Specific case like condition in when:
// element is dead but its only child is alive and has the same text range
else listOf(element.textRange.endOffset.let { TextRange(it, it) })
}
}
else {
listOf(element.textRange!!)
}
}
private fun KtElement.hasChildrenInSet(set: Set): Boolean {
return PsiTreeUtil.collectElements(this) { it != this }.any { it in set }
}
private fun KtElement.getLeavesOrReachableChildren(): List {
val children = ArrayList()
acceptChildren(object : PsiElementVisitor() {
override fun visitElement(element: PsiElement) {
val isReachable = element is KtElement && reachableElements.contains(element) && !element.hasChildrenInSet(unreachableElements)
if (isReachable || element.children.isEmpty()) {
children.add(element)
}
else {
element.acceptChildren(this)
}
}
})
return children
}
fun List.removeReachableElementsWithMeaninglessSiblings(): List {
fun PsiElement.isMeaningless() = this is PsiWhiteSpace
|| this.node?.elementType == KtTokens.COMMA
|| this is PsiComment
val childrenToRemove = HashSet()
fun collectSiblingsIfMeaningless(elementIndex: Int, direction: Int) {
val index = elementIndex + direction
if (index !in 0..(size - 1)) return
val element = this[index]
if (element.isMeaningless()) {
childrenToRemove.add(element)
collectSiblingsIfMeaningless(index, direction)
}
}
for ((index, element) in this.withIndex()) {
if (reachableElements.contains(element)) {
childrenToRemove.add(element)
collectSiblingsIfMeaningless(index, -1)
collectSiblingsIfMeaningless(index, 1)
}
}
return this.filter { it !in childrenToRemove }
}
private fun List.mergeAdjacentTextRanges(): List {
val result = ArrayList()
val lastRange = fold(null as TextRange?) {
currentTextRange, element ->
val elementRange = element.textRange!!
when {
currentTextRange == null -> {
elementRange
}
currentTextRange.endOffset == elementRange.startOffset -> {
currentTextRange.union(elementRange)
}
else -> {
result.add(currentTextRange)
elementRange
}
}
}
if (lastRange != null) {
result.add(lastRange)
}
return result
}
}