/*******************************************************************************
* Copyright (c) 2010, 2013 Severin Gehwolf
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Severin Gehwolf - initial API and implementation
*******************************************************************************/
package org.eclipse.cdt.codan.internal.checkers;
import org.eclipse.cdt.codan.core.cxx.model.AbstractIndexAstChecker;
import org.eclipse.cdt.core.dom.ast.ASTVisitor;
import org.eclipse.cdt.core.dom.ast.IASTBinaryExpression;
import org.eclipse.cdt.core.dom.ast.IASTExpression;
import org.eclipse.cdt.core.dom.ast.IASTTranslationUnit;
/**
* Checker that finds assignment to itself cases, such a
* a = a. It can produce some false positives such as
* a[f()]=a[f()] - but who writes code like that?
*/
public class AssignmentToItselfChecker extends AbstractIndexAstChecker {
private static final String ER_ID = "org.eclipse.cdt.codan.internal.checkers.AssignmentToItselfProblem"; //$NON-NLS-1$
@Override
public void processAst(IASTTranslationUnit ast) {
// Traverse the ast using the visitor pattern.
ast.accept(new ASTVisitor() {
{ // constructor
shouldVisitExpressions = true;
}
// visit expressions
@Override
public int visit(IASTExpression expression) {
if (isAssignmentToItself(expression)) {
reportProblem(ER_ID, expression, expression.getRawSignature());
}
return PROCESS_CONTINUE;
}
private boolean isAssignmentToItself(IASTExpression expr) {
if (expr instanceof IASTBinaryExpression) {
IASTBinaryExpression binExpr = (IASTBinaryExpression) expr;
if (binExpr.getOperator() == IASTBinaryExpression.op_assign) {
IASTExpression operand1 = binExpr.getOperand1();
IASTExpression operand2 = binExpr.getOperand2();
if (operand1 != null && operand2 != null) {
String op1 = operand1.getRawSignature();
String op2 = operand2.getRawSignature();
String exprImage = binExpr.getRawSignature();
return op1.equals(op2)
// When macro is used, RawSignature returns macro name, see bug 321933
&& !op1.equals(exprImage);
}
}
}
return false;
}
});
}
}