001    /*
002     * Copyright 2010-2013 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.jet.lang.psi;
018    
019    import com.google.common.base.Function;
020    import com.google.common.base.Predicate;
021    import com.google.common.collect.Lists;
022    import com.intellij.lang.ASTNode;
023    import com.intellij.openapi.util.Condition;
024    import com.intellij.psi.*;
025    import com.intellij.psi.impl.CheckUtil;
026    import com.intellij.psi.impl.source.codeStyle.CodeEditUtil;
027    import com.intellij.psi.tree.IElementType;
028    import com.intellij.psi.util.PsiTreeUtil;
029    import com.intellij.util.codeInsight.CommentUtilCore;
030    import com.intellij.util.containers.ContainerUtil;
031    import org.jetbrains.annotations.NotNull;
032    import org.jetbrains.annotations.Nullable;
033    import org.jetbrains.jet.JetNodeTypes;
034    import org.jetbrains.jet.kdoc.psi.api.KDocElement;
035    import org.jetbrains.jet.lang.parsing.JetExpressionParsing;
036    import org.jetbrains.jet.lang.psi.psiUtil.PsiUtilPackage;
037    import org.jetbrains.jet.lang.resolve.ImportPath;
038    import org.jetbrains.jet.lang.resolve.name.FqName;
039    import org.jetbrains.jet.lang.resolve.name.FqNameUnsafe;
040    import org.jetbrains.jet.lang.resolve.name.Name;
041    import org.jetbrains.jet.lang.resolve.name.SpecialNames;
042    import org.jetbrains.jet.lang.types.expressions.OperatorConventions;
043    import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
044    import org.jetbrains.jet.lexer.JetToken;
045    import org.jetbrains.jet.lexer.JetTokens;
046    
047    import java.util.*;
048    
049    public class JetPsiUtil {
050        private JetPsiUtil() {
051        }
052    
053        public interface JetExpressionWrapper {
054            JetExpression getBaseExpression();
055        }
056    
057        public static <D> void visitChildren(@NotNull JetElement element, @NotNull JetTreeVisitor<D> visitor, D data) {
058            PsiElement child = element.getFirstChild();
059            while (child != null) {
060                if (child instanceof JetElement) {
061                    ((JetElement) child).accept(visitor, data);
062                }
063                child = child.getNextSibling();
064            }
065        }
066    
067        @NotNull
068        public static JetExpression safeDeparenthesize(@NotNull JetExpression expression, boolean deparenthesizeBinaryExpressionWithTypeRHS) {
069            JetExpression deparenthesized = deparenthesize(expression, deparenthesizeBinaryExpressionWithTypeRHS);
070            return deparenthesized != null ? deparenthesized : expression;
071        }
072    
073        @Nullable
074        public static JetExpression deparenthesize(@Nullable JetExpression expression) {
075            return deparenthesize(expression, true);
076        }
077    
078        @Nullable
079        public static JetExpression deparenthesize(
080                @Nullable JetExpression expression,
081                boolean deparenthesizeBinaryExpressionWithTypeRHS
082        ) {
083            return deparenthesizeWithResolutionStrategy(expression, deparenthesizeBinaryExpressionWithTypeRHS, null);
084        }
085    
086        @Nullable
087        @Deprecated //Use JetPsiUtil.deparenthesize() or ExpressionTypingServices.deparenthesize()
088        public static JetExpression deparenthesizeWithResolutionStrategy(
089                @Nullable JetExpression expression,
090                boolean deparenthesizeBinaryExpressionWithTypeRHS,
091                @Nullable Function<JetTypeReference, Void> typeResolutionStrategy
092        ) {
093            if (deparenthesizeBinaryExpressionWithTypeRHS && expression instanceof JetBinaryExpressionWithTypeRHS) {
094                JetBinaryExpressionWithTypeRHS binaryExpression = (JetBinaryExpressionWithTypeRHS) expression;
095                JetSimpleNameExpression operationSign = binaryExpression.getOperationReference();
096                if (JetTokens.COLON.equals(operationSign.getReferencedNameElementType())) {
097                    expression = binaryExpression.getLeft();
098                    JetTypeReference typeReference = binaryExpression.getRight();
099                    if (typeResolutionStrategy != null && typeReference != null) {
100                        typeResolutionStrategy.apply(typeReference);
101                    }
102                }
103            }
104            else if (expression instanceof JetPrefixExpression) {
105                JetExpression baseExpression = getBaseExpressionIfLabeledExpression((JetPrefixExpression) expression);
106                if (baseExpression != null) {
107                    expression = baseExpression;
108                }
109            }
110            else if (expression instanceof JetExpressionWrapper) {
111                expression = ((JetExpressionWrapper) expression).getBaseExpression();
112            }
113            if (expression instanceof JetParenthesizedExpression) {
114                JetExpression innerExpression = ((JetParenthesizedExpression) expression).getExpression();
115                return innerExpression != null ? deparenthesizeWithResolutionStrategy(
116                        innerExpression, deparenthesizeBinaryExpressionWithTypeRHS, typeResolutionStrategy) : null;
117            }
118            return expression;
119        }
120    
121        @Nullable
122        public static JetExpression getBaseExpressionIfLabeledExpression(@NotNull JetPrefixExpression expression) {
123            if (isLabeledExpression(expression)) {
124                return expression.getBaseExpression();
125            }
126            return null;
127        }
128    
129        public static boolean isLabeledExpression(JetPrefixExpression expression) {
130            return JetTokens.LABELS.contains(expression.getOperationReference().getReferencedNameElementType());
131        }
132    
133        @NotNull
134        public static Name safeName(@Nullable String name) {
135            return name == null ? SpecialNames.NO_NAME_PROVIDED : Name.identifier(name);
136        }
137    
138        @NotNull
139        public static Set<JetElement> findRootExpressions(@NotNull Collection<JetElement> unreachableElements) {
140            Set<JetElement> rootElements = new HashSet<JetElement>();
141            final Set<JetElement> shadowedElements = new HashSet<JetElement>();
142            JetVisitorVoid shadowAllChildren = new JetVisitorVoid() {
143                @Override
144                public void visitJetElement(@NotNull JetElement element) {
145                    if (shadowedElements.add(element)) {
146                        element.acceptChildren(this);
147                    }
148                }
149            };
150    
151            for (JetElement element : unreachableElements) {
152                if (shadowedElements.contains(element)) continue;
153                element.acceptChildren(shadowAllChildren);
154    
155                rootElements.removeAll(shadowedElements);
156                rootElements.add(element);
157            }
158            return rootElements;
159        }
160    
161        @NotNull
162        public static String unquoteIdentifier(@NotNull String quoted) {
163            if (quoted.indexOf('`') < 0) {
164                return quoted;
165            }
166    
167            if (quoted.startsWith("`") && quoted.endsWith("`") && quoted.length() >= 2) {
168                return quoted.substring(1, quoted.length() - 1);
169            }
170            else {
171                return quoted;
172            }
173        }
174    
175        @NotNull
176        public static String unquoteIdentifierOrFieldReference(@NotNull String quoted) {
177            if (quoted.indexOf('`') < 0) {
178                return quoted;
179            }
180    
181            if (quoted.startsWith("$")) {
182                return "$" + unquoteIdentifier(quoted.substring(1));
183            }
184            else {
185                return unquoteIdentifier(quoted);
186            }
187        }
188    
189        @NotNull
190        public static FqName getFQName(@NotNull JetFile file) {
191            JetPackageDirective directive = file.getPackageDirective();
192            return directive != null ? directive.getFqName() : FqName.ROOT;
193        }
194    
195        @Nullable
196        public static FqNameUnsafe getUnsafeFQName(@NotNull JetNamedDeclaration namedDeclaration) {
197            FqName fqName = getFQName(namedDeclaration);
198            return fqName != null ? fqName.toUnsafe() : null;
199        }
200    
201        @Nullable
202        public static FqName getFQName(@NotNull JetNamedDeclaration namedDeclaration) {
203            Name name = namedDeclaration.getNameAsName();
204            if (name == null) {
205                return null;
206            }
207    
208            PsiElement parent = namedDeclaration.getParent();
209            if (parent instanceof JetClassBody) {
210                // One nesting to JetClassBody doesn't affect to qualified name
211                parent = parent.getParent();
212            }
213    
214            FqName firstPart = null;
215            if (parent instanceof JetFile) {
216                firstPart = getFQName((JetFile) parent);
217            }
218            else if (parent instanceof JetNamedFunction || parent instanceof JetClass) {
219                firstPart = getFQName((JetNamedDeclaration) parent);
220            }
221            else if (namedDeclaration instanceof JetParameter) {
222                JetClass constructorClass = getClassIfParameterIsProperty((JetParameter) namedDeclaration);
223                if (constructorClass != null) {
224                    firstPart = getFQName(constructorClass);
225                }
226            }
227            else if (parent instanceof JetObjectDeclaration) {
228                if (parent.getParent() instanceof JetClassObject) {
229                    JetClassOrObject classOrObject = PsiTreeUtil.getParentOfType(parent, JetClassOrObject.class);
230                    if (classOrObject != null) {
231                        firstPart = getFQName(classOrObject);
232                    }
233                }
234                else {
235                    firstPart = getFQName((JetNamedDeclaration) parent);
236                }
237            }
238    
239            if (firstPart == null) {
240                return null;
241            }
242    
243            return firstPart.child(name);
244        }
245    
246        /** @return <code>null</code> iff the tye has syntactic errors */
247        @Nullable
248        public static FqName toQualifiedName(@NotNull JetUserType userType) {
249            List<String> reversedNames = Lists.newArrayList();
250    
251            JetUserType current = userType;
252            while (current != null) {
253                String name = current.getReferencedName();
254                if (name == null) return null;
255    
256                reversedNames.add(name);
257                current = current.getQualifier();
258            }
259    
260            return FqName.fromSegments(ContainerUtil.reverse(reversedNames));
261        }
262    
263        @Nullable
264        public static Name getShortName(@NotNull JetAnnotationEntry annotation) {
265            JetTypeReference typeReference = annotation.getTypeReference();
266            assert typeReference != null : "Annotation entry hasn't typeReference " + annotation.getText();
267            JetTypeElement typeElement = typeReference.getTypeElement();
268            if (typeElement instanceof JetUserType) {
269                JetUserType userType = (JetUserType) typeElement;
270                String shortName = userType.getReferencedName();
271                if (shortName != null) {
272                    return Name.identifier(shortName);
273                }
274            }
275            return null;
276        }
277    
278        public static boolean isDeprecated(@NotNull JetModifierListOwner owner) {
279            JetModifierList modifierList = owner.getModifierList();
280            if (modifierList != null) {
281                List<JetAnnotationEntry> annotationEntries = modifierList.getAnnotationEntries();
282                for (JetAnnotationEntry annotation : annotationEntries) {
283                    Name shortName = getShortName(annotation);
284                    if (KotlinBuiltIns.getInstance().getDeprecatedAnnotation().getName().equals(shortName)) {
285                        return true;
286                    }
287                }
288            }
289            return false;
290        }
291    
292        @Nullable
293        @IfNotParsed
294        public static ImportPath getImportPath(@NotNull JetImportDirective importDirective) {
295            if (PsiTreeUtil.hasErrorElements(importDirective)) {
296                return null;
297            }
298    
299            FqName importFqn = getFQName(importDirective.getImportedReference());
300            if (importFqn == null) {
301                return null;
302            }
303    
304            Name alias = null;
305            String aliasName = importDirective.getAliasName();
306            if (aliasName != null) {
307                alias = Name.identifier(aliasName);
308            }
309    
310            return new ImportPath(importFqn, importDirective.isAllUnder(), alias);
311        }
312    
313        @Nullable
314        public static <T extends PsiElement> T getDirectParentOfTypeForBlock(@NotNull JetBlockExpression block, @NotNull Class<T> aClass) {
315            T parent = PsiTreeUtil.getParentOfType(block, aClass);
316            if (parent instanceof JetIfExpression) {
317                JetIfExpression ifExpression = (JetIfExpression) parent;
318                if (ifExpression.getElse() == block || ifExpression.getThen() == block) {
319                    return parent;
320                }
321            }
322            if (parent instanceof JetWhenExpression) {
323                JetWhenExpression whenExpression = (JetWhenExpression) parent;
324                for (JetWhenEntry whenEntry : whenExpression.getEntries()) {
325                    if (whenEntry.getExpression() == block) {
326                        return parent;
327                    }
328                }
329            }
330            if (parent instanceof JetFunctionLiteral) {
331                JetFunctionLiteral functionLiteral = (JetFunctionLiteral) parent;
332                if (functionLiteral.getBodyExpression() == block) {
333                    return parent;
334                }
335            }
336            if (parent instanceof JetTryExpression) {
337                JetTryExpression tryExpression = (JetTryExpression) parent;
338                if (tryExpression.getTryBlock() == block) {
339                    return parent;
340                }
341                for (JetCatchClause clause : tryExpression.getCatchClauses()) {
342                    if (clause.getCatchBody() == block) {
343                        return parent;
344                    }
345                }
346            }
347            return null;
348        }
349    
350        public static boolean isImplicitlyUsed(@NotNull JetElement element) {
351            PsiElement parent = element.getParent();
352            if (!(parent instanceof JetBlockExpression)) return true;
353            JetBlockExpression block = (JetBlockExpression) parent;
354            List<JetElement> statements = block.getStatements();
355            if (statements.get(statements.size() - 1) == element) {
356                JetExpression expression = getDirectParentOfTypeForBlock(block, JetIfExpression.class);
357                if (expression == null) {
358                    expression = getDirectParentOfTypeForBlock(block, JetWhenExpression.class);
359                }
360                if (expression == null) {
361                    expression = getDirectParentOfTypeForBlock(block, JetFunctionLiteral.class);
362                }
363                if (expression == null) {
364                    expression = getDirectParentOfTypeForBlock(block, JetTryExpression.class);
365                }
366                if (expression != null) {
367                    return isImplicitlyUsed(expression);
368                }
369            }
370            return false;
371        }
372    
373        public static void deleteClass(@NotNull JetClassOrObject clazz) {
374            CheckUtil.checkWritable(clazz);
375            JetFile file = (JetFile) clazz.getContainingFile();
376            if (isLocal(clazz) || file.getDeclarations().size() > 1) {
377                PsiElement parent = clazz.getParent();
378                CodeEditUtil.removeChild(parent.getNode(), clazz.getNode());
379            }
380            else {
381                file.delete();
382            }
383        }
384    
385        @Nullable
386        public static Name getAliasName(@NotNull JetImportDirective importDirective) {
387            String aliasName = importDirective.getAliasName();
388            JetExpression importedReference = importDirective.getImportedReference();
389            if (importedReference == null) {
390                return null;
391            }
392            JetSimpleNameExpression referenceExpression = getLastReference(importedReference);
393            if (aliasName == null) {
394                aliasName = referenceExpression != null ? referenceExpression.getReferencedName() : null;
395            }
396    
397            return aliasName != null && !aliasName.isEmpty() ? Name.identifier(aliasName) : null;
398        }
399    
400        @Nullable
401        public static JetSimpleNameExpression getLastReference(@NotNull JetExpression importedReference) {
402            JetElement selector = PsiUtilPackage.getQualifiedElementSelector(importedReference);
403            return selector instanceof JetSimpleNameExpression ? (JetSimpleNameExpression) selector : null;
404        }
405    
406        public static boolean isSelectorInQualified(@NotNull JetSimpleNameExpression nameExpression) {
407            JetElement qualifiedElement = PsiUtilPackage.getQualifiedElement(nameExpression);
408            return qualifiedElement instanceof JetQualifiedExpression
409                   || ((qualifiedElement instanceof JetUserType) && ((JetUserType) qualifiedElement).getQualifier() != null);
410        }
411    
412        public static boolean isLHSOfDot(@NotNull JetExpression expression) {
413            PsiElement parent = expression.getParent();
414            if (!(parent instanceof JetQualifiedExpression)) return false;
415            JetQualifiedExpression qualifiedParent = (JetQualifiedExpression) parent;
416            return qualifiedParent.getReceiverExpression() == expression || isLHSOfDot(qualifiedParent);
417        }
418    
419        public static boolean isVoidType(@Nullable JetTypeReference typeReference) {
420            if (typeReference == null) {
421                return false;
422            }
423    
424            return KotlinBuiltIns.getInstance().getUnit().getName().asString().equals(typeReference.getText());
425        }
426    
427        public static boolean isSafeCall(@NotNull Call call) {
428            ASTNode callOperationNode = call.getCallOperationNode();
429            return callOperationNode != null && callOperationNode.getElementType() == JetTokens.SAFE_ACCESS;
430        }
431    
432        public static boolean isScriptDeclaration(@NotNull JetDeclaration namedDeclaration) {
433            return getScript(namedDeclaration) != null;
434        }
435    
436        @Nullable
437        public static JetScript getScript(@NotNull JetDeclaration namedDeclaration) {
438            PsiElement parent = namedDeclaration.getParent();
439            if (parent != null && parent.getParent() instanceof JetScript) {
440                return (JetScript) parent.getParent();
441            }
442            else {
443                return null;
444            }
445        }
446    
447        public static boolean isVariableNotParameterDeclaration(@NotNull JetDeclaration declaration) {
448            if (!(declaration instanceof JetVariableDeclaration)) return false;
449            if (declaration instanceof JetProperty) return true;
450            assert declaration instanceof JetMultiDeclarationEntry;
451            JetMultiDeclarationEntry multiDeclarationEntry = (JetMultiDeclarationEntry) declaration;
452            return !(multiDeclarationEntry.getParent().getParent() instanceof JetForExpression);
453        }
454    
455        @Nullable
456        public static Name getConventionName(@NotNull JetSimpleNameExpression simpleNameExpression) {
457            if (simpleNameExpression.getIdentifier() != null) {
458                return simpleNameExpression.getReferencedNameAsName();
459            }
460    
461            PsiElement firstChild = simpleNameExpression.getFirstChild();
462            if (firstChild != null) {
463                IElementType elementType = firstChild.getNode().getElementType();
464                if (elementType instanceof JetToken) {
465                    JetToken jetToken = (JetToken) elementType;
466                    return OperatorConventions.getNameForOperationSymbol(jetToken);
467                }
468            }
469    
470            return null;
471        }
472    
473        @Nullable
474        public static PsiElement getTopmostParentOfTypes(@Nullable PsiElement element, @NotNull Class<? extends PsiElement>... parentTypes) {
475            if (element == null) {
476                return null;
477            }
478    
479            PsiElement result = null;
480            PsiElement parent = element.getParent();
481            while (parent != null) {
482                if (PsiTreeUtil.instanceOf(parent, parentTypes)) {
483                    result = parent;
484                }
485    
486                parent = parent.getParent();
487            }
488    
489            return result;
490        }
491    
492        public static boolean isNullConstant(@NotNull JetExpression expression) {
493            JetExpression deparenthesized = deparenthesize(expression);
494            return deparenthesized instanceof JetConstantExpression && deparenthesized.getNode().getElementType() == JetNodeTypes.NULL;
495        }
496    
497        public static boolean isAbstract(@NotNull JetDeclarationWithBody declaration) {
498            return declaration.getBodyExpression() == null;
499        }
500    
501        public static boolean isBackingFieldReference(@NotNull JetSimpleNameExpression expression) {
502            return expression.getReferencedNameElementType() == JetTokens.FIELD_IDENTIFIER;
503        }
504    
505        public static boolean isBackingFieldReference(@Nullable JetElement element) {
506            return element instanceof JetSimpleNameExpression && isBackingFieldReference((JetSimpleNameExpression)element);
507        }
508    
509        @Nullable
510        private static FqName getFQName(@Nullable JetExpression expression) {
511            if (expression == null) {
512                return null;
513            }
514    
515            if (expression instanceof JetDotQualifiedExpression) {
516                JetDotQualifiedExpression dotQualifiedExpression = (JetDotQualifiedExpression) expression;
517                FqName parentFqn = getFQName(dotQualifiedExpression.getReceiverExpression());
518                Name child = getName(dotQualifiedExpression.getSelectorExpression());
519    
520                return parentFqn != null && child != null ? parentFqn.child(child) : null;
521            }
522            else if (expression instanceof JetSimpleNameExpression) {
523                JetSimpleNameExpression simpleNameExpression = (JetSimpleNameExpression) expression;
524                return FqName.topLevel(simpleNameExpression.getReferencedNameAsName());
525            }
526            else {
527                throw new IllegalArgumentException("Can't construct fqn for: " + expression.getClass().toString());
528            }
529        }
530    
531        @Nullable
532        private static Name getName(@Nullable JetExpression expression) {
533            if (expression == null) {
534                return null;
535            }
536    
537            if (expression instanceof JetSimpleNameExpression) {
538                return ((JetSimpleNameExpression) expression).getReferencedNameAsName();
539            }
540            else {
541                throw new IllegalArgumentException("Can't construct name for: " + expression.getClass().toString());
542            }
543        }
544    
545        @Nullable
546        public static JetElement getLastStatementInABlock(@Nullable JetBlockExpression blockExpression) {
547            if (blockExpression == null) return null;
548            List<JetElement> statements = blockExpression.getStatements();
549            return statements.isEmpty() ? null : statements.get(statements.size() - 1);
550        }
551    
552        public static boolean isTrait(@NotNull JetClassOrObject classOrObject) {
553            return classOrObject instanceof JetClass && ((JetClass) classOrObject).isTrait();
554        }
555    
556        @Nullable
557        public static JetClassOrObject getOutermostClassOrObject(@NotNull JetClassOrObject classOrObject) {
558            JetClassOrObject current = classOrObject;
559            while (true) {
560                PsiElement parent = current.getParent();
561                assert classOrObject.getParent() != null : "Class with no parent: " + classOrObject.getText();
562    
563                if (parent instanceof PsiFile) {
564                    return current;
565                }
566                if (parent instanceof JetClassObject) {
567                    // current class IS the class object declaration
568                    parent = parent.getParent();
569                    assert parent instanceof JetClassBody : "Parent of class object is not a class body: " + parent;
570                }
571                if (!(parent instanceof JetClassBody)) {
572                    // It is a local class, no legitimate outer
573                    return current;
574                }
575    
576                current = (JetClassOrObject) parent.getParent();
577            }
578        }
579    
580        @Nullable
581        public static JetClass getClassIfParameterIsProperty(@NotNull JetParameter jetParameter) {
582            if (jetParameter.getValOrVarNode() != null) {
583                PsiElement parent = jetParameter.getParent();
584                if (parent instanceof JetParameterList && parent.getParent() instanceof JetClass) {
585                    return (JetClass) parent.getParent();
586                }
587            }
588    
589            return null;
590        }
591    
592        @Nullable
593        private static IElementType getOperation(@NotNull JetExpression expression) {
594            if (expression instanceof JetQualifiedExpression) {
595                return ((JetQualifiedExpression) expression).getOperationSign();
596            }
597            else if (expression instanceof JetOperationExpression) {
598                return ((JetOperationExpression) expression).getOperationReference().getReferencedNameElementType();
599            }
600            return null;
601        }
602    
603    
604        private static int getPriority(@NotNull JetExpression expression) {
605            int maxPriority = JetExpressionParsing.Precedence.values().length + 1;
606    
607            // same as postfix operations
608            if (expression instanceof JetPostfixExpression ||
609                expression instanceof JetQualifiedExpression ||
610                expression instanceof JetCallExpression ||
611                expression instanceof JetArrayAccessExpression) {
612                return maxPriority - 1;
613            }
614    
615            if (expression instanceof JetPrefixExpression) return maxPriority - 2;
616    
617            if (expression instanceof JetDeclaration || expression instanceof JetStatementExpression || expression instanceof JetIfExpression) {
618                return 0;
619            }
620    
621            IElementType operation = getOperation(expression);
622            for (JetExpressionParsing.Precedence precedence : JetExpressionParsing.Precedence.values()) {
623                if (precedence != JetExpressionParsing.Precedence.PREFIX && precedence != JetExpressionParsing.Precedence.POSTFIX &&
624                    precedence.getOperations().contains(operation)) {
625                    return maxPriority - precedence.ordinal() - 1;
626                }
627            }
628    
629            return maxPriority;
630        }
631    
632        public static boolean areParenthesesUseless(@NotNull JetParenthesizedExpression expression) {
633            JetExpression innerExpression = expression.getExpression();
634            if (innerExpression == null) return true;
635    
636            PsiElement parent = expression.getParent();
637            if (!(parent instanceof JetExpression)) return true;
638    
639            return !areParenthesesNecessary(innerExpression, expression, (JetExpression) parent);
640        }
641    
642        public static boolean areParenthesesNecessary(@NotNull JetExpression innerExpression, @NotNull JetExpression currentInner, @NotNull JetExpression parentExpression) {
643            if (parentExpression instanceof JetParenthesizedExpression || innerExpression instanceof JetParenthesizedExpression) {
644                return false;
645            }
646    
647            if (parentExpression instanceof JetPackageDirective) return false;
648    
649            if (parentExpression instanceof JetWhenExpression || innerExpression instanceof JetWhenExpression) {
650                return false;
651            }
652    
653            if (innerExpression instanceof JetIfExpression) {
654                PsiElement current = parentExpression;
655    
656                while (!(current instanceof JetBlockExpression || current instanceof JetDeclaration || current instanceof JetStatementExpression)) {
657                    if (current.getTextRange().getEndOffset() != currentInner.getTextRange().getEndOffset()) {
658                        return current.getText().charAt(current.getTextLength() - 1) != ')'; // if current expression is "guarded" by parenthesis, no extra parenthesis is necessary
659                    }
660    
661                    current = current.getParent();
662                }
663            }
664    
665            IElementType innerOperation = getOperation(innerExpression);
666            IElementType parentOperation = getOperation(parentExpression);
667    
668            // 'return (@label{...})' case
669            if (parentExpression instanceof JetReturnExpression && innerOperation == JetTokens.LABEL_IDENTIFIER) {
670                return true;
671            }
672    
673            // '(x: Int) < y' case
674            if (innerExpression instanceof JetBinaryExpressionWithTypeRHS && parentOperation == JetTokens.LT) {
675                return true;
676            }
677    
678            int innerPriority = getPriority(innerExpression);
679            int parentPriority = getPriority(parentExpression);
680    
681            if (innerPriority == parentPriority) {
682                if (parentExpression instanceof JetBinaryExpression) {
683                    if (innerOperation == JetTokens.ANDAND || innerOperation == JetTokens.OROR) {
684                        return false;
685                    }
686                    return ((JetBinaryExpression) parentExpression).getRight() == currentInner;
687                }
688    
689                //'-(-x)' case
690                if (parentExpression instanceof JetPrefixExpression && innerExpression instanceof JetPrefixExpression) {
691                    return innerOperation == parentOperation && (innerOperation == JetTokens.PLUS || innerOperation == JetTokens.MINUS);
692                }
693                return false;
694            }
695    
696            return innerPriority < parentPriority;
697        }
698    
699        public static boolean isAssignment(@NotNull PsiElement element) {
700            return element instanceof JetBinaryExpression &&
701                   JetTokens.ALL_ASSIGNMENTS.contains(((JetBinaryExpression) element).getOperationToken());
702        }
703    
704        public static boolean isOrdinaryAssignment(@NotNull PsiElement element) {
705            return element instanceof JetBinaryExpression &&
706                   ((JetBinaryExpression) element).getOperationToken().equals(JetTokens.EQ);
707        }
708    
709        @Nullable
710        public static JetElement getOutermostLastBlockElement(@Nullable JetElement element, @NotNull Predicate<JetElement> checkElement) {
711            if (element == null) return null;
712    
713            if (!(element instanceof JetBlockExpression)) return checkElement.apply(element) ? element : null;
714    
715            JetBlockExpression block = (JetBlockExpression)element;
716            int n = block.getStatements().size();
717    
718            if (n == 0) return null;
719    
720            JetElement lastElement = block.getStatements().get(n - 1);
721            return checkElement.apply(lastElement) ? lastElement : null;
722        }
723    
724        public static boolean checkVariableDeclarationInBlock(@NotNull JetBlockExpression block, @NotNull String varName) {
725            for (JetElement element : block.getStatements()) {
726                if (element instanceof JetVariableDeclaration) {
727                    if (((JetVariableDeclaration) element).getNameAsSafeName().asString().equals(varName)) {
728                        return true;
729                    }
730                }
731            }
732    
733            return false;
734        }
735    
736        public static boolean checkWhenExpressionHasSingleElse(@NotNull JetWhenExpression whenExpression) {
737            int elseCount = 0;
738            for (JetWhenEntry entry : whenExpression.getEntries()) {
739                if (entry.isElse()) {
740                    elseCount++;
741                }
742            }
743            return (elseCount == 1);
744        }
745    
746        @Nullable
747        public static PsiElement skipTrailingWhitespacesAndComments(@Nullable PsiElement element)  {
748            return PsiTreeUtil.skipSiblingsForward(element, PsiWhiteSpace.class, PsiComment.class);
749        }
750    
751        public static final Predicate<JetElement> ANY_JET_ELEMENT = new Predicate<JetElement>() {
752            @Override
753            public boolean apply(@Nullable JetElement input) {
754                return true;
755            }
756        };
757    
758        @NotNull
759        public static String getText(@Nullable PsiElement element) {
760            return element != null ? element.getText() : "";
761        }
762    
763        @Nullable
764        public static String getNullableText(@Nullable PsiElement element) {
765            return element != null ? element.getText() : null;
766        }
767    
768        /**
769         * CommentUtilCore.isComment fails if element <strong>inside</strong> comment.
770         *
771         * Also, we can not add KDocTokens to COMMENTS TokenSet, because it is used in JetParserDefinition.getCommentTokens(),
772         * and therefor all COMMENTS tokens will be ignored by PsiBuilder.
773         *
774         * @param element
775         * @return
776         */
777        public static boolean isInComment(PsiElement element) {
778            return CommentUtilCore.isComment(element) || element instanceof KDocElement;
779        }
780    
781        @Nullable
782        public static PsiElement getOutermostParent(@NotNull PsiElement element, @NotNull PsiElement upperBound, boolean strict) {
783            PsiElement parent = strict ? element.getParent() : element;
784            while (parent != null && parent.getParent() != upperBound) {
785                parent = parent.getParent();
786            }
787    
788            return parent;
789        }
790    
791        public static <T extends PsiElement> T getLastChildByType(@NotNull PsiElement root, @NotNull Class<? extends T>... elementTypes) {
792            PsiElement[] children = root.getChildren();
793    
794            for (int i = children.length - 1; i >= 0; i--) {
795                if (PsiTreeUtil.instanceOf(children[i], elementTypes)) {
796                    //noinspection unchecked
797                    return (T) children[i];
798                }
799            }
800    
801            return null;
802        }
803    
804        @Nullable
805        public static JetElement getOutermostDescendantElement(
806                @Nullable PsiElement root,
807                boolean first,
808                final @NotNull Predicate<JetElement> predicate
809        ) {
810            if (!(root instanceof JetElement)) return null;
811    
812            final List<JetElement> results = Lists.newArrayList();
813    
814            ((JetElement) root).accept(
815                    new JetVisitorVoid() {
816                        @Override
817                        public void visitJetElement(@NotNull JetElement element) {
818                            if (predicate.apply(element)) {
819                                //noinspection unchecked
820                                results.add(element);
821                            }
822                            else {
823                                element.acceptChildren(this);
824                            }
825                        }
826                    }
827            );
828    
829            if (results.isEmpty()) return null;
830    
831            return first ? results.get(0) : results.get(results.size() - 1);
832        }
833    
834        @Nullable
835        public static PsiElement findChildByType(@NotNull PsiElement element, @NotNull IElementType type) {
836            ASTNode node = element.getNode().findChildByType(type);
837            return node == null ? null : node.getPsi();
838        }
839    
840        @Nullable
841        public static JetExpression getCalleeExpressionIfAny(@NotNull JetExpression expression) {
842            if (expression instanceof JetSimpleNameExpression) {
843                return expression;
844            }
845            if (expression instanceof JetCallElement) {
846                JetCallElement callExpression = (JetCallElement) expression;
847                return callExpression.getCalleeExpression();
848            }
849            if (expression instanceof JetQualifiedExpression) {
850                JetExpression selectorExpression = ((JetQualifiedExpression) expression).getSelectorExpression();
851                if (selectorExpression != null) {
852                    return getCalleeExpressionIfAny(selectorExpression);
853                }
854            }
855            if (expression instanceof JetUnaryExpression) {
856                return ((JetUnaryExpression) expression).getOperationReference();
857            }
858            if (expression instanceof JetBinaryExpression) {
859                return ((JetBinaryExpression) expression).getOperationReference();
860            }
861            return null;
862        }
863    
864        @Nullable
865        public static PsiElement skipSiblingsBackwardByPredicate(@Nullable PsiElement element, Predicate<PsiElement> elementsToSkip) {
866            if (element == null) return null;
867            for (PsiElement e = element.getPrevSibling(); e != null; e = e.getPrevSibling()) {
868                if (elementsToSkip.apply(e)) continue;
869                return e;
870            }
871            return null;
872        }
873    
874        @Nullable
875        public static PsiElement skipSiblingsForwardByPredicate(@Nullable PsiElement element, Predicate<PsiElement> elementsToSkip) {
876            if (element == null) return null;
877            for (PsiElement e = element.getNextSibling(); e != null; e = e.getNextSibling()) {
878                if (elementsToSkip.apply(e)) continue;
879                return e;
880            }
881            return null;
882        }
883    
884        public static NavigatablePsiElement getPackageReference(@NotNull JetFile file, int partIndex) {
885            JetPackageDirective directive = file.getPackageDirective();
886            if (directive == null) {
887                throw new IllegalArgumentException("Should be called only for files with package directive: " + file);
888            }
889    
890            List<JetSimpleNameExpression> names = directive.getPackageNames();
891            if (!(0 <= partIndex && partIndex < names.size())) {
892                throw new IndexOutOfBoundsException(String.format("%s index for file with directive %s is out of range", partIndex,
893                                                                  directive.getText()));
894            }
895    
896            return names.get(partIndex);
897        }
898    
899        // Delete given element and all the elements separating it from the neighboring elements of the same class
900        public static void deleteElementWithDelimiters(@NotNull PsiElement element) {
901            PsiElement paramBefore = PsiTreeUtil.getPrevSiblingOfType(element, element.getClass());
902    
903            PsiElement from;
904            PsiElement to;
905            if (paramBefore != null) {
906                from = paramBefore.getNextSibling();
907                to = element;
908            }
909            else {
910                PsiElement paramAfter = PsiTreeUtil.getNextSiblingOfType(element, element.getClass());
911    
912                from = element;
913                to = paramAfter != null ? paramAfter.getPrevSibling() : element;
914            }
915    
916            PsiElement parent = element.getParent();
917    
918            parent.deleteChildRange(from, to);
919        }
920    
921        // Delete element if it doesn't contain children of a given type
922        public static <T extends PsiElement> void deleteChildlessElement(PsiElement element, Class<T> childClass) {
923            if (PsiTreeUtil.getChildrenOfType(element, childClass) == null) {
924                element.delete();
925            }
926        }
927    
928        public static PsiElement ascendIfPropertyAccessor(PsiElement element) {
929            if (element instanceof JetPropertyAccessor) {
930                return element.getParent();
931            }
932            return element;
933        }
934    
935        @NotNull
936        public static String getElementTextWithContext(@NotNull JetElement element) {
937            if (element instanceof JetFile) {
938                return element.getContainingFile().getText();
939            }
940    
941            // Find parent for element among file children
942            PsiElement inFileParent = PsiTreeUtil.findFirstParent(element, new Condition<PsiElement>() {
943                @Override
944                public boolean value(PsiElement parentCandidate) {
945                    return parentCandidate != null && parentCandidate.getParent() instanceof JetFile;
946                }
947            });
948    
949            assert inFileParent != null : "For non-file element we should always be able to find parent in file children";
950    
951            int startContextOffset = inFileParent.getTextRange().getStartOffset();
952            int elementContextOffset = element.getTextRange().getStartOffset();
953    
954            int inFileParentOffset = elementContextOffset - startContextOffset;
955    
956            return new StringBuilder(inFileParent.getText()).insert(inFileParentOffset, "<caret>").toString();
957        }
958    
959        @Nullable
960        public static JetModifierList replaceModifierList(@NotNull JetModifierListOwner owner, @Nullable JetModifierList modifierList) {
961            JetModifierList oldModifierList = owner.getModifierList();
962            if (modifierList == null) {
963                if (oldModifierList != null) oldModifierList.delete();
964                return null;
965            }
966            else {
967                if (oldModifierList == null) {
968                    PsiElement firstChild = owner.getFirstChild();
969                    return (JetModifierList) owner.addBefore(modifierList, firstChild);
970                }
971                else {
972                    return (JetModifierList) oldModifierList.replace(modifierList);
973                }
974            }
975        }
976    
977        @Nullable
978        public static String getPackageName(@NotNull JetElement element) {
979            JetFile file = (JetFile) element.getContainingFile();
980            JetPackageDirective header = PsiTreeUtil.findChildOfType(file, JetPackageDirective.class);
981    
982            return header != null ? header.getQualifiedName() : null;
983        }
984    
985        @Nullable
986        public static JetElement getEnclosingElementForLocalDeclaration(@Nullable JetDeclaration declaration) {
987            if (declaration instanceof JetTypeParameter) {
988                declaration = PsiTreeUtil.getParentOfType(declaration, JetNamedDeclaration.class);
989            }
990            else if (declaration instanceof JetParameter) {
991                PsiElement parent = declaration.getParent();
992                if (parent != null && parent.getParent() instanceof JetNamedFunction) {
993                    declaration = (JetNamedFunction) parent.getParent();
994                }
995            }
996    
997            //noinspection unchecked
998            JetElement container = PsiTreeUtil.getParentOfType(
999                    declaration,
1000                    JetBlockExpression.class, JetClassInitializer.class, JetProperty.class, JetFunction.class, JetParameter.class
1001            );
1002            if (container == null) return null;
1003    
1004            return (container instanceof JetClassInitializer) ? ((JetClassInitializer) container).getBody() : container;
1005        }
1006    
1007        public static boolean isLocal(@NotNull JetDeclaration declaration) {
1008            return getEnclosingElementForLocalDeclaration(declaration) != null;
1009        }
1010    
1011        @Nullable
1012        public static JetToken getOperationToken(@NotNull JetOperationExpression expression) {
1013            JetSimpleNameExpression operationExpression = expression.getOperationReference();
1014            IElementType elementType = operationExpression.getReferencedNameElementType();
1015            assert elementType == null || elementType instanceof JetToken :
1016                    "JetOperationExpression should have operation token of type JetToken: " +
1017                    expression;
1018            return (JetToken) elementType;
1019        }
1020    
1021        public static boolean isLabelIdentifierExpression(PsiElement element) {
1022            return element instanceof JetSimpleNameExpression &&
1023                   ((JetSimpleNameExpression) element).getReferencedNameElementType() == JetTokens.LABEL_IDENTIFIER;
1024        }
1025    }