package edu.umd.cs.findbugs.plugin.eclipse.quickfix;
import static edu.umd.cs.findbugs.plugin.eclipse.quickfix.util.ASTUtil.getMethodDeclaration;
import static edu.umd.cs.findbugs.plugin.eclipse.quickfix.util.ASTUtil.getTypeDeclaration;
import java.util.List;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.CastExpression;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.ConditionalExpression;
import org.eclipse.jdt.core.dom.Expression;
import org.eclipse.jdt.core.dom.FieldAccess;
import org.eclipse.jdt.core.dom.InfixExpression;
import org.eclipse.jdt.core.dom.MethodDeclaration;
import org.eclipse.jdt.core.dom.MethodInvocation;
import org.eclipse.jdt.core.dom.ReturnStatement;
import org.eclipse.jdt.core.dom.SimpleName;
import org.eclipse.jdt.core.dom.Statement;
import org.eclipse.jdt.core.dom.ThisExpression;
import org.eclipse.jdt.core.dom.Type;
import org.eclipse.jdt.core.dom.TypeDeclaration;
import org.eclipse.jdt.core.dom.rewrite.ASTRewrite;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.plugin.eclipse.quickfix.exception.BugResolutionException;
/**
* Returning a reference to a mutable object is not recommended. The class
* <CODE>CreateMutableCloneResolution</CODE> returns a new copy of the object.
*
* @see <a
* href="http://findbugs.sourceforge.net/bugDescriptions.html#EI_EXPOSE_REP">EI_EXPOSE_REP</a>
*/
public class CreateMutableCloneResolution extends BugResolution {
@Override
public boolean resolveBindings() {
return true;
}
@Override
protected void repairBug(ASTRewrite rewrite, CompilationUnit workingUnit, BugInstance bug) throws BugResolutionException {
assert rewrite != null;
assert workingUnit != null;
assert bug != null;
TypeDeclaration type = getTypeDeclaration(workingUnit, bug.getPrimaryClass());
MethodDeclaration method = getMethodDeclaration(type, bug.getPrimaryMethod());
String fieldName = bug.getPrimaryField().getFieldName();
SimpleName original = null;
for (Statement stmt : (List<Statement>) method.getBody().statements()) {
if (stmt instanceof ReturnStatement) {
Expression retEx = ((ReturnStatement) stmt).getExpression();
if (retEx instanceof SimpleName && ((SimpleName) retEx).getIdentifier().equals(fieldName)) {
original = (SimpleName) retEx;
break;
} else if (retEx instanceof FieldAccess && isThisFieldAccess((FieldAccess) retEx, fieldName)) {
original = ((FieldAccess) retEx).getName();
break;
}
}
}
if (original == null) {
throw new BugResolutionException("No original field found.");
}
// set up the clone part
MethodInvocation cloneInvoke = invokeClone(workingUnit, original);
// cast the result to the right type
CastExpression castRet = workingUnit.getAST().newCastExpression();
castRet.setExpression(cloneInvoke);
Type retType = (Type) ASTNode.copySubtree(castRet.getAST(), method.getReturnType2());
castRet.setType(retType);
ConditionalExpression conditionalExpression = workingUnit.getAST().newConditionalExpression();
conditionalExpression.setElseExpression(castRet);
conditionalExpression.setThenExpression(workingUnit.getAST().newNullLiteral() );
InfixExpression nullTest = workingUnit.getAST().newInfixExpression();
nullTest.setOperator(InfixExpression.Operator.EQUALS);
nullTest.setRightOperand(workingUnit.getAST().newNullLiteral());
Expression initialLoad = (SimpleName) ASTNode.copySubtree(cloneInvoke.getAST(), original);
nullTest.setLeftOperand(initialLoad);
conditionalExpression.setExpression(nullTest);
rewrite.replace(original, conditionalExpression, null);
}
/**
* @param workingUnit
* @param original
* @return
*/
private MethodInvocation invokeClone(CompilationUnit workingUnit, SimpleName original) {
MethodInvocation cloneInvoke = workingUnit.getAST().newMethodInvocation();
Expression cloneField = (SimpleName) ASTNode.copySubtree(cloneInvoke.getAST(), original);
SimpleName cloneName = workingUnit.getAST().newSimpleName("clone");
cloneInvoke.setExpression(cloneField);
cloneInvoke.setName(cloneName);
return cloneInvoke;
}
private boolean isThisFieldAccess(FieldAccess access, String fieldName) {
return (access.getExpression() instanceof ThisExpression) && access.getName().getIdentifier().equals(fieldName);
}
}