KT-7730 Find Usages causes 100% CPU usage, UI blocked, never returned

KT-7623 Renaming val constructor parameter of a data class is very slow

 #KT-7730 fixed
 #KT-7730 fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/findUsages/JetFindUsagesProvider.kt

@@ -26,8 +26,7 @@ public class JetFindUsagesProvider : FindUsagesProvider {
     public override fun canFindUsagesFor(psiElement: PsiElement): Boolean =
             psiElement is JetNamedDeclaration
 
-    public override fun getWordsScanner(): WordsScanner =
-            KotlinWordsScanner()
+    public override fun getWordsScanner() = null
 
     public override fun getHelpId(psiElement: PsiElement): String? = null
 

idea/idea-analysis/src/org/jetbrains/kotlin/idea/findUsages/KotlinWordsScanner.kt

@@ -1,62 +0,0 @@
-/*
- * 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.idea.findUsages
-
-import org.jetbrains.kotlin.idea.search.usagesSearch.*
-import com.intellij.lang.cacheBuilder.WordsScanner
-import com.intellij.util.Processor
-import org.jetbrains.kotlin.lexer.JetLexer
-import com.intellij.lang.cacheBuilder.WordOccurrence
-import org.jetbrains.kotlin.lexer.JetTokens
-import com.intellij.lang.cacheBuilder.SimpleWordsScanner
-
-class KotlinWordsScanner() : WordsScanner {
-    private val lexer = JetLexer()
-    private val simpleWordsScanner = SimpleWordsScanner()
-
-    fun scanWords(kind: WordOccurrence.Kind, processor: Processor<WordOccurrence>) {
-        val tokenStart = lexer.getTokenStart()
-        simpleWordsScanner.processWords(lexer.getTokenSequence()) {
-            it!!.init(lexer.getBufferSequence(), tokenStart + it.getStart(), tokenStart + it.getEnd(), kind)
-            processor.process(it)
-        }
-    }
-
-    override fun processWords(fileText: CharSequence, processor: Processor<WordOccurrence>) {
-        lexer.start(fileText)
-
-        val occurrence = WordOccurrence(null, 0, 0, null)
-        var valOrVarBefore: Boolean = false
-
-        stream { lexer.getTokenType() }.forEach { elementType ->
-            // todo: replace with when
-            if (ALL_SEARCHABLE_OPERATIONS.contains(elementType) || (valOrVarBefore && elementType == JetTokens.LPAR)) {
-                occurrence.init(lexer.getBufferSequence(), lexer.getTokenStart(), lexer.getTokenEnd(), WordOccurrence.Kind.CODE)
-                processor.process(occurrence)
-            }
-            else if (JetTokens.COMMENTS.contains(elementType)) scanWords(WordOccurrence.Kind.COMMENTS, processor)
-            else if (JetTokens.STRINGS.contains(elementType)) scanWords(WordOccurrence.Kind.LITERALS, processor)
-            else scanWords(WordOccurrence.Kind.CODE, processor)
-
-            if (elementType !in JetTokens.WHITE_SPACE_OR_COMMENT_BIT_SET) {
-                valOrVarBefore = elementType == JetTokens.VAL_KEYWORD || elementType == JetTokens.VAR_KEYWORD
-            }
-
-            lexer.advance()
-        }
-    }
-}

idea/idea-analysis/src/org/jetbrains/kotlin/idea/search/KotlinIndexers.kt

@@ -24,11 +24,13 @@ import com.intellij.psi.impl.cache.impl.OccurrenceConsumer
 import com.intellij.psi.impl.cache.impl.id.LexerBasedIdIndexer
 import com.intellij.psi.impl.cache.impl.todo.LexerBasedTodoIndexer
 import com.intellij.psi.search.UsageSearchContext
+import com.intellij.psi.tree.IElementType
 import com.intellij.psi.tree.TokenSet
 import org.jetbrains.kotlin.idea.search.usagesSearch.ALL_SEARCHABLE_OPERATIONS
 import org.jetbrains.kotlin.kdoc.lexer.KDocTokens
 import org.jetbrains.kotlin.lexer.JetLexer
 import org.jetbrains.kotlin.lexer.JetTokens
+import java.util.*
 
 class KotlinFilterLexer(table: OccurrenceConsumer): BaseFilterLexer(JetLexer(), table) {
     private val codeTokens = TokenSet.orSet(
@@ -43,11 +45,19 @@ class KotlinFilterLexer(table: OccurrenceConsumer): BaseFilterLexer(JetLexer(),
             JetTokens.RBRACKET, JetTokens.SEMICOLON, JetTokens.COMMA, JetTokens.DOT
     )
 
+    private var previousTokens = LinkedList<IElementType>()
+
     override fun advance() {
+        fun isMultiDeclarationPosition(): Boolean {
+            return previousTokens[0] == JetTokens.VAL_KEYWORD || previousTokens[0] == JetTokens.VAR_KEYWORD
+                   || previousTokens[0] == JetTokens.LPAR && previousTokens[1] == JetTokens.FOR_KEYWORD
+        }
+
         val tokenType = myDelegate.getTokenType()
 
-        when(tokenType) {
+        when (tokenType) {
             in codeTokens -> addOccurrenceInToken(UsageSearchContext.IN_CODE.toInt())
+            JetTokens.LPAR -> if (isMultiDeclarationPosition()) addOccurrenceInToken(UsageSearchContext.IN_CODE.toInt())
             in JetTokens.STRINGS -> scanWordsInToken(UsageSearchContext.IN_STRINGS + UsageSearchContext.IN_FOREIGN_LANGUAGES, false, true)
             in commentTokens -> {
                 scanWordsInToken(UsageSearchContext.IN_COMMENTS.toInt(), false, false)
@@ -56,6 +66,14 @@ class KotlinFilterLexer(table: OccurrenceConsumer): BaseFilterLexer(JetLexer(),
             !in skipTokens -> scanWordsInToken(UsageSearchContext.IN_PLAIN_TEXT.toInt(), false, false)
         }
 
+        if (tokenType != TokenType.WHITE_SPACE) {
+            previousTokens.addFirst(tokenType)
+
+            if (previousTokens.size() > 2) {
+                previousTokens.removeLast()
+            }
+        }
+
         myDelegate.advance()
     }
 }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/search/usagesSearch/conventions.kt

@@ -35,7 +35,6 @@ public val ALL_SEARCHABLE_OPERATIONS: ImmutableSet<JetToken> = ImmutableSet
         .addAll(IDENTITY_EQUALS_OPERATIONS)
         .addAll(IN_OPERATIONS)
         .add(JetTokens.LBRACKET)
-        .add(JetTokens.LPAR)
         .add(JetTokens.BY_KEYWORD)
         .build()
 

idea/testData/findUsages/kotlin/conventions/componentFunctions.1.kt

@@ -0,0 +1,4 @@
+fun test() {
+    for ((x, y, z) in array<A>()) {
+    }
+}

idea/testData/findUsages/kotlin/conventions/componentFunctions.results.txt

@@ -1,3 +1,4 @@
 Function call (9: 7) a.component1()
 Value read (10: 9) val (x, y, z) = a
+Value read (2: 10) for ((x, y, z) in array<A>()) {
 Value read (8: 7) a.n