| /* |
| * Copyright 2003-2009 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.dataflow; |
| |
| import com.intellij.psi.*; |
| import com.intellij.psi.tree.IElementType; |
| import com.intellij.psi.util.PsiTreeUtil; |
| import com.siyeh.InspectionGadgetsBundle; |
| import com.siyeh.ig.BaseInspection; |
| import com.siyeh.ig.BaseInspectionVisitor; |
| import com.siyeh.ig.psiutils.VariableAccessUtils; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| public class ReuseOfLocalVariableInspectionBase |
| extends BaseInspection { |
| |
| @Override |
| @NotNull |
| public String getDisplayName() { |
| return InspectionGadgetsBundle.message( |
| "reuse.of.local.variable.display.name"); |
| } |
| |
| @Override |
| @NotNull |
| public String buildErrorString(Object... infos) { |
| return InspectionGadgetsBundle.message( |
| "reuse.of.local.variable.problem.descriptor"); |
| } |
| |
| @Override |
| public BaseInspectionVisitor buildVisitor() { |
| return new ReuseOfLocalVariableVisitor(); |
| } |
| |
| private static class ReuseOfLocalVariableVisitor |
| extends BaseInspectionVisitor { |
| |
| @Override |
| public void visitAssignmentExpression( |
| @NotNull PsiAssignmentExpression assignment) { |
| super.visitAssignmentExpression(assignment); |
| final PsiElement assignmentParent = assignment.getParent(); |
| if (!(assignmentParent instanceof PsiExpressionStatement)) { |
| return; |
| } |
| final PsiExpression lhs = assignment.getLExpression(); |
| if (!(lhs instanceof PsiReferenceExpression)) { |
| return; |
| } |
| final PsiReferenceExpression reference = |
| (PsiReferenceExpression)lhs; |
| final PsiElement referent = reference.resolve(); |
| if (!(referent instanceof PsiLocalVariable)) { |
| return; |
| } |
| final PsiVariable variable = (PsiVariable)referent; |
| |
| //TODO: this is safe, but can be weakened |
| if (variable.getInitializer() == null) { |
| return; |
| } |
| final IElementType tokenType = assignment.getOperationTokenType(); |
| if (!JavaTokenType.EQ.equals(tokenType)) { |
| return; |
| } |
| final PsiExpression rhs = assignment.getRExpression(); |
| if (rhs != null && |
| VariableAccessUtils.variableIsUsed(variable, rhs)) { |
| return; |
| } |
| final PsiCodeBlock variableBlock = |
| PsiTreeUtil.getParentOfType(variable, PsiCodeBlock.class); |
| if (variableBlock == null) { |
| return; |
| } |
| |
| if (loopExistsBetween(assignment, variableBlock)) { |
| return; |
| } |
| if (tryExistsBetween(assignment, variableBlock)) { |
| // this could be weakened, slightly, if it could be verified |
| // that a variable is used in only one branch of a try statement |
| return; |
| } |
| final PsiElement assignmentBlock = |
| assignmentParent.getParent(); |
| if (assignmentBlock == null) { |
| return; |
| } |
| if (variableBlock.equals(assignmentBlock)) { |
| registerError(lhs); |
| } |
| final PsiStatement[] statements = variableBlock.getStatements(); |
| final PsiElement containingStatement = |
| getChildWhichContainsElement(variableBlock, assignment); |
| int statementPosition = -1; |
| for (int i = 0; i < statements.length; i++) { |
| if (statements[i].equals(containingStatement)) { |
| statementPosition = i; |
| break; |
| } |
| } |
| if (statementPosition == -1) { |
| return; |
| } |
| for (int i = statementPosition + 1; i < statements.length; i++) { |
| if (VariableAccessUtils.variableIsUsed(variable, statements[i])) { |
| return; |
| } |
| } |
| registerError(lhs); |
| } |
| |
| private static boolean loopExistsBetween( |
| PsiAssignmentExpression assignment, PsiCodeBlock block) { |
| PsiElement elementToTest = assignment; |
| while (elementToTest != null) { |
| if (elementToTest.equals(block)) { |
| return false; |
| } |
| if (elementToTest instanceof PsiWhileStatement || |
| elementToTest instanceof PsiForeachStatement || |
| elementToTest instanceof PsiForStatement || |
| elementToTest instanceof PsiDoWhileStatement) { |
| return true; |
| } |
| elementToTest = elementToTest.getParent(); |
| } |
| return false; |
| } |
| |
| private static boolean tryExistsBetween( |
| PsiAssignmentExpression assignment, PsiCodeBlock block) { |
| PsiElement elementToTest = assignment; |
| while (elementToTest != null) { |
| if (elementToTest.equals(block)) { |
| return false; |
| } |
| if (elementToTest instanceof PsiTryStatement) { |
| return true; |
| } |
| elementToTest = elementToTest.getParent(); |
| } |
| return false; |
| } |
| |
| /** |
| * @noinspection AssignmentToMethodParameter |
| */ |
| @Nullable |
| public static PsiElement getChildWhichContainsElement( |
| @NotNull PsiCodeBlock ancestor, |
| @NotNull PsiElement descendant) { |
| PsiElement element = descendant; |
| while (!element.equals(ancestor)) { |
| descendant = element; |
| element = descendant.getParent(); |
| if (element == null) { |
| return null; |
| } |
| } |
| return descendant; |
| } |
| } |
| } |