| /* |
| * Copyright 2003-2008 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.performance; |
| |
| import com.intellij.psi.*; |
| import com.intellij.psi.tree.IElementType; |
| import com.siyeh.ig.psiutils.ControlFlowUtils; |
| import org.jetbrains.annotations.NotNull; |
| |
| class StringVariableIsAppendedToVisitor extends JavaRecursiveElementVisitor { |
| |
| private boolean appendedTo = false; |
| private final PsiVariable variable; |
| private final boolean onlyWarnOnLoop; |
| |
| StringVariableIsAppendedToVisitor(PsiVariable variable, |
| boolean onlyWarnOnLoop) { |
| super(); |
| this.variable = variable; |
| this.onlyWarnOnLoop = onlyWarnOnLoop; |
| } |
| |
| @Override |
| public void visitAssignmentExpression( |
| @NotNull PsiAssignmentExpression assignment) { |
| if (appendedTo) { |
| return; |
| } |
| super.visitAssignmentExpression(assignment); |
| final PsiExpression lhs = assignment.getLExpression(); |
| final PsiExpression rhs = assignment.getRExpression(); |
| if (rhs == null) { |
| return; |
| } |
| if (!(lhs instanceof PsiReferenceExpression)) { |
| return; |
| } |
| final PsiReferenceExpression reference = (PsiReferenceExpression)lhs; |
| final PsiExpression qualifier = reference.getQualifierExpression(); |
| if (qualifier != null) { |
| return; |
| } |
| final PsiElement referent = reference.resolve(); |
| if (!variable.equals(referent)) { |
| return; |
| } |
| final IElementType tokenType = assignment.getOperationTokenType(); |
| if (tokenType.equals(JavaTokenType.PLUSEQ)) { |
| if (onlyWarnOnLoop && !ControlFlowUtils.isInLoop(assignment)) { |
| return; |
| } |
| appendedTo = true; |
| } |
| else if (isConcatenation(rhs)) { |
| if (onlyWarnOnLoop && !ControlFlowUtils.isInLoop(assignment)) { |
| return; |
| } |
| appendedTo = true; |
| } |
| } |
| |
| private boolean isConcatenation(PsiExpression expression) { |
| if (expression == null) { |
| return false; |
| } |
| if (expression instanceof PsiReferenceExpression) { |
| final PsiElement referent = ((PsiReference)expression).resolve(); |
| return variable.equals(referent); |
| } |
| if (expression instanceof PsiParenthesizedExpression) { |
| final PsiExpression body = |
| ((PsiParenthesizedExpression)expression).getExpression(); |
| return isConcatenation(body); |
| } |
| if (expression instanceof PsiBinaryExpression) { |
| final PsiBinaryExpression binaryExpression = |
| (PsiBinaryExpression)expression; |
| final PsiExpression lhs = binaryExpression.getLOperand(); |
| final PsiExpression rhs = binaryExpression.getROperand(); |
| return isConcatenation(lhs) || isConcatenation(rhs); |
| } |
| return false; |
| } |
| |
| public boolean isAppendedTo() { |
| return appendedTo; |
| } |
| } |