| /* |
| * Copyright 2008-2010 Dave Griffith, Bas Leijdekkers |
| * |
| * 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 com.siyeh.ig.psiutils; |
| |
| import com.intellij.psi.*; |
| import com.intellij.psi.tree.IElementType; |
| import org.jetbrains.annotations.NotNull; |
| |
| class VariableValueUsedVisitor extends JavaRecursiveElementVisitor { |
| |
| @NotNull |
| private final PsiVariable variable; |
| private boolean read = false; |
| private boolean written = false; |
| |
| VariableValueUsedVisitor(@NotNull PsiVariable variable) { |
| this.variable = variable; |
| } |
| |
| @Override |
| public void visitElement(@NotNull PsiElement element) { |
| if (read || written) { |
| return; |
| } |
| super.visitElement(element); |
| } |
| |
| @Override |
| public void visitAssignmentExpression( |
| @NotNull PsiAssignmentExpression assignment) { |
| if (read || written) { |
| return; |
| } |
| super.visitAssignmentExpression(assignment); |
| final PsiExpression lhs = assignment.getLExpression(); |
| if (lhs instanceof PsiReferenceExpression) { |
| PsiReferenceExpression referenceExpression = |
| (PsiReferenceExpression)lhs; |
| final PsiElement target = referenceExpression.resolve(); |
| if (variable.equals(target)) { |
| written = true; |
| return; |
| } |
| } |
| final PsiExpression rhs = assignment.getRExpression(); |
| if (rhs == null) { |
| return; |
| } |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| rhs.accept(visitor); |
| read = visitor.isUsed(); |
| } |
| |
| @Override |
| public void visitPrefixExpression( |
| @NotNull PsiPrefixExpression prefixExpression) { |
| if (read || written) { |
| return; |
| } |
| super.visitPrefixExpression(prefixExpression); |
| final IElementType tokenType = prefixExpression.getOperationTokenType(); |
| if (!tokenType.equals(JavaTokenType.PLUSPLUS) && |
| !tokenType.equals(JavaTokenType.MINUSMINUS)) { |
| return; |
| } |
| final PsiExpression operand = prefixExpression.getOperand(); |
| if (!(operand instanceof PsiReferenceExpression)) { |
| return; |
| } |
| final PsiReferenceExpression referenceExpression = |
| (PsiReferenceExpression)operand; |
| final PsiElement target = referenceExpression.resolve(); |
| if (!variable.equals(target)) { |
| return; |
| } |
| written = true; |
| } |
| |
| @Override |
| public void visitPostfixExpression( |
| @NotNull PsiPostfixExpression postfixExpression) { |
| if (read || written) { |
| return; |
| } |
| super.visitPostfixExpression(postfixExpression); |
| final IElementType tokenType = postfixExpression.getOperationTokenType(); |
| if (!tokenType.equals(JavaTokenType.PLUSPLUS) && |
| !tokenType.equals(JavaTokenType.MINUSMINUS)) { |
| return; |
| } |
| final PsiExpression operand = postfixExpression.getOperand(); |
| if (!(operand instanceof PsiReferenceExpression)) { |
| return; |
| } |
| final PsiReferenceExpression referenceExpression = |
| (PsiReferenceExpression)operand; |
| final PsiElement target = referenceExpression.resolve(); |
| if (!variable.equals(target)) { |
| return; |
| } |
| written = true; |
| } |
| |
| @Override |
| public void visitVariable(@NotNull PsiVariable variable) { |
| if (read || written) { |
| return; |
| } |
| super.visitVariable(variable); |
| final PsiExpression initalizer = variable.getInitializer(); |
| if (initalizer == null) { |
| return; |
| } |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| initalizer.accept(visitor); |
| read = visitor.isUsed(); |
| } |
| |
| @Override |
| public void visitMethodCallExpression( |
| @NotNull PsiMethodCallExpression call) { |
| if (read || written) { |
| return; |
| } |
| super.visitMethodCallExpression(call); |
| final PsiReferenceExpression methodExpression = |
| call.getMethodExpression(); |
| final PsiExpression qualifier = |
| methodExpression.getQualifierExpression(); |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| if (qualifier != null) { |
| qualifier.accept(visitor); |
| if (visitor.isUsed()) { |
| read = true; |
| return; |
| } |
| } |
| final PsiExpressionList argumentList = call.getArgumentList(); |
| final PsiExpression[] arguments = argumentList.getExpressions(); |
| for (final PsiExpression argument : arguments) { |
| argument.accept(visitor); |
| if (visitor.isUsed()) { |
| read = true; |
| return; |
| } |
| } |
| } |
| |
| @Override |
| public void visitNewExpression( |
| @NotNull PsiNewExpression newExpression) { |
| if (read || written) { |
| return; |
| } |
| super.visitNewExpression(newExpression); |
| final PsiExpressionList argumentList = |
| newExpression.getArgumentList(); |
| if (argumentList == null) { |
| return; |
| } |
| final PsiExpression[] arguments = argumentList.getExpressions(); |
| for (final PsiExpression argument : arguments) { |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| argument.accept(visitor); |
| if (visitor.isUsed()) { |
| read = true; |
| return; |
| } |
| } |
| } |
| |
| @Override |
| public void visitArrayInitializerExpression( |
| PsiArrayInitializerExpression expression) { |
| if (read || written) { |
| return; |
| } |
| super.visitArrayInitializerExpression(expression); |
| final PsiExpression[] arguments = expression.getInitializers(); |
| for (final PsiExpression argument : arguments) { |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| argument.accept(visitor); |
| if (visitor.isUsed()) { |
| read = true; |
| return; |
| } |
| } |
| } |
| |
| @Override |
| public void visitReturnStatement( |
| @NotNull PsiReturnStatement returnStatement) { |
| if (read || written) { |
| return; |
| } |
| super.visitReturnStatement(returnStatement); |
| final PsiExpression returnValue = returnStatement.getReturnValue(); |
| if (returnValue == null) { |
| return; |
| } |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| returnValue.accept(visitor); |
| read = visitor.isUsed(); |
| } |
| |
| /** |
| * check if variable is used in nested/inner class. |
| */ |
| @Override |
| public void visitClass(PsiClass aClass) { |
| if (read || written) { |
| return; |
| } |
| super.visitClass(aClass); |
| final VariableUsedVisitor visitor = |
| new VariableUsedVisitor(variable); |
| aClass.accept(visitor); |
| read = visitor.isUsed(); |
| } |
| |
| public boolean isVariableValueUsed() { |
| return read; |
| } |
| } |