| /* |
| * Copyright 2008-2013 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.bugs; |
| |
| import com.intellij.psi.*; |
| import com.intellij.psi.tree.IElementType; |
| import com.intellij.psi.util.PsiUtil; |
| import com.siyeh.InspectionGadgetsBundle; |
| import com.siyeh.ig.BaseInspection; |
| import com.siyeh.ig.BaseInspectionVisitor; |
| import com.siyeh.ig.psiutils.ParenthesesUtils; |
| import com.siyeh.ig.psiutils.VariableAccessUtils; |
| import org.jetbrains.annotations.Nls; |
| import org.jetbrains.annotations.NotNull; |
| |
| public class VariableNotUsedInsideIfInspection extends BaseInspection { |
| |
| @Override |
| @Nls |
| @NotNull |
| public String getDisplayName() { |
| return InspectionGadgetsBundle.message("variable.not.used.inside.if.display.name"); |
| } |
| |
| @Override |
| @NotNull |
| protected String buildErrorString(Object... infos) { |
| final boolean isIf = ((Boolean)infos[0]).booleanValue(); |
| if (isIf) { |
| return InspectionGadgetsBundle.message("variable.not.used.inside.if.problem.descriptor"); |
| } |
| else { |
| return InspectionGadgetsBundle.message("variable.not.used.inside.conditional.problem.descriptor"); |
| } |
| } |
| |
| @Override |
| public BaseInspectionVisitor buildVisitor() { |
| return new VariableNotUsedInsideIfVisitor(); |
| } |
| |
| private static class VariableNotUsedInsideIfVisitor extends BaseInspectionVisitor { |
| |
| @Override |
| public void visitConditionalExpression(PsiConditionalExpression expression) { |
| super.visitConditionalExpression(expression); |
| final PsiExpression condition = PsiUtil.skipParenthesizedExprDown(expression.getCondition()); |
| if (!(condition instanceof PsiBinaryExpression)) { |
| return; |
| } |
| final PsiBinaryExpression binaryExpression = (PsiBinaryExpression)condition; |
| final PsiReferenceExpression referenceExpression = extractVariableReference(binaryExpression); |
| if (referenceExpression == null) { |
| return; |
| } |
| final IElementType tokenType = binaryExpression.getOperationTokenType(); |
| if (tokenType == JavaTokenType.EQEQ) { |
| if (checkVariableUsage(referenceExpression, expression.getThenExpression(), expression.getElseExpression())) { |
| registerError(referenceExpression, Boolean.FALSE); |
| } |
| } |
| else if (tokenType == JavaTokenType.NE) { |
| if (checkVariableUsage(referenceExpression, expression.getElseExpression(), expression.getThenExpression())) { |
| registerError(referenceExpression, Boolean.FALSE); |
| } |
| } |
| } |
| |
| @Override |
| public void visitIfStatement(PsiIfStatement statement) { |
| super.visitIfStatement(statement); |
| final PsiExpression condition = ParenthesesUtils.stripParentheses(statement.getCondition()); |
| if (!(condition instanceof PsiBinaryExpression)) { |
| return; |
| } |
| final PsiBinaryExpression binaryExpression = (PsiBinaryExpression)condition; |
| final PsiReferenceExpression referenceExpression = extractVariableReference(binaryExpression); |
| if (referenceExpression == null) { |
| return; |
| } |
| final IElementType tokenType = binaryExpression.getOperationTokenType(); |
| if (tokenType == JavaTokenType.EQEQ) { |
| if (checkVariableUsage(referenceExpression, statement.getThenBranch(), statement.getElseBranch())) { |
| registerError(referenceExpression, Boolean.TRUE); |
| } |
| } |
| else if (tokenType == JavaTokenType.NE) { |
| if (checkVariableUsage(referenceExpression, statement.getElseBranch(), statement.getThenBranch())) { |
| registerError(referenceExpression, Boolean.TRUE); |
| } |
| } |
| } |
| |
| private boolean checkVariableUsage(PsiReferenceExpression referenceExpression, PsiElement thenContext, PsiElement elseContext) { |
| final PsiElement target = referenceExpression.resolve(); |
| if (!(target instanceof PsiVariable)) { |
| return false; |
| } |
| final PsiVariable variable = (PsiVariable)target; |
| if (thenContext != null && (contextExits(thenContext) || VariableAccessUtils.variableIsAssigned(variable, thenContext))) { |
| return false; |
| } |
| if (elseContext == null || VariableAccessUtils.variableIsUsed(variable, elseContext)) { |
| return false; |
| } |
| return true; |
| } |
| |
| private static PsiReferenceExpression extractVariableReference(PsiBinaryExpression expression) { |
| final PsiExpression lhs = ParenthesesUtils.stripParentheses(expression.getLOperand()); |
| if (lhs == null) { |
| return null; |
| } |
| final PsiExpression rhs = ParenthesesUtils.stripParentheses(expression.getROperand()); |
| if (rhs == null) { |
| return null; |
| } |
| if (PsiType.NULL.equals(rhs.getType())) { |
| if (!(lhs instanceof PsiReferenceExpression)) { |
| return null; |
| } |
| return (PsiReferenceExpression)lhs; |
| } |
| if (PsiType.NULL.equals(lhs.getType())) { |
| if (!(rhs instanceof PsiReferenceExpression)) { |
| return null; |
| } |
| return (PsiReferenceExpression)rhs; |
| } |
| return null; |
| } |
| |
| private static boolean contextExits(PsiElement context) { |
| if (context instanceof PsiBlockStatement) { |
| final PsiBlockStatement blockStatement = (PsiBlockStatement)context; |
| final PsiCodeBlock codeBlock = blockStatement.getCodeBlock(); |
| final PsiStatement[] statements = codeBlock.getStatements(); |
| if (statements.length == 0) { |
| return false; |
| } |
| final PsiStatement lastStatement = statements[statements.length - 1]; |
| return statementExits(lastStatement); |
| } |
| else { |
| return statementExits(context); |
| } |
| } |
| |
| private static boolean statementExits(PsiElement context) { |
| return context instanceof PsiReturnStatement || context instanceof PsiThrowStatement || |
| context instanceof PsiBreakStatement || context instanceof PsiContinueStatement; |
| } |
| } |
| } |