/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2003-2005, University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.detect;
import java.util.Set;
import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.ConstantNameAndType;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.ClassAnnotation;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.MethodAnnotation;
import edu.umd.cs.findbugs.Priorities;
import edu.umd.cs.findbugs.StatelessDetector;
import edu.umd.cs.findbugs.ba.AnalysisContext;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.PruneUnconditionalExceptionThrowerEdges;
import edu.umd.cs.findbugs.ba.XFactory;
import edu.umd.cs.findbugs.ba.ch.Subtypes2;
import edu.umd.cs.findbugs.bcel.BCELUtil;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;
import edu.umd.cs.findbugs.classfile.DescriptorFactory;
import edu.umd.cs.findbugs.visitclass.DismantleBytecode;
public class CloneIdiom extends DismantleBytecode implements Detector, StatelessDetector {
private final ClassDescriptor cloneDescriptor = DescriptorFactory.createClassDescriptor(java.lang.Cloneable.class);
boolean isCloneable, hasCloneMethod;
boolean cloneIsDeprecated;
MethodAnnotation cloneMethodAnnotation;
boolean referencesCloneMethod;
boolean invokesSuperClone;
boolean isFinal;
boolean cloneOnlyThrowsException;
boolean check;
// boolean throwsExceptions;
boolean implementsCloneableDirectly;
private final BugReporter bugReporter;
public CloneIdiom(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public void visitClassContext(ClassContext classContext) {
classContext.getJavaClass().accept(this);
}
@Override
public void visit(Code obj) {
if (getMethodName().equals("clone") && getMethodSig().startsWith("()")) {
super.visit(obj);
}
}
@Override
public void sawOpcode(int seen) {
if (seen == INVOKESPECIAL && getNameConstantOperand().equals("clone") && getSigConstantOperand().startsWith("()")) {
/*
* System.out.println("Saw call to " + nameConstant + ":" +
* sigConstant + " in " + betterMethodName);
*/
invokesSuperClone = true;
}
}
@Override
public void visit(JavaClass obj) {
implementsCloneableDirectly = false;
invokesSuperClone = false;
cloneOnlyThrowsException = false;
isCloneable = false;
check = false;
isFinal = obj.isFinal();
if (obj.isInterface()) {
return;
}
if (obj.isAbstract()) {
return;
}
// Does this class directly implement Cloneable?
String[] interface_names = obj.getInterfaceNames();
for (String interface_name : interface_names) {
if (interface_name.equals("java.lang.Cloneable")) {
implementsCloneableDirectly = true;
isCloneable = true;
break;
}
}
Subtypes2 subtypes2 = AnalysisContext.currentAnalysisContext().getSubtypes2();
try {
if (subtypes2.isSubtype(getClassDescriptor(), cloneDescriptor)) {
isCloneable = true;
}
if (subtypes2.isSubtype(DescriptorFactory.createClassDescriptorFromDottedClassName(obj.getSuperclassName()),
cloneDescriptor)) {
implementsCloneableDirectly = false;
}
} catch (ClassNotFoundException e) {
bugReporter.reportMissingClass(e);
}
hasCloneMethod = false;
referencesCloneMethod = false;
check = true;
super.visit(obj);
}
@Override
public void visitAfter(JavaClass obj) {
if (!check) {
return;
}
if (cloneOnlyThrowsException) {
return;
}
if (implementsCloneableDirectly && !hasCloneMethod) {
if (!referencesCloneMethod) {
bugReporter.reportBug(new BugInstance(this, "CN_IDIOM", NORMAL_PRIORITY).addClass(this));
}
}
if (hasCloneMethod && isCloneable && !invokesSuperClone && !isFinal && obj.isPublic()) {
int priority = LOW_PRIORITY;
if (obj.isPublic() || obj.isProtected()) {
priority = NORMAL_PRIORITY;
}
try {
Subtypes2 subtypes2 = AnalysisContext.currentAnalysisContext().getSubtypes2();
Set<ClassDescriptor> directSubtypes = subtypes2.getDirectSubtypes(getClassDescriptor());
if (!directSubtypes.isEmpty()) {
priority--;
}
BugInstance bug = new BugInstance(this, "CN_IDIOM_NO_SUPER_CALL", priority).addClass(this).addMethod(
cloneMethodAnnotation);
for (ClassDescriptor d : directSubtypes) {
bug.addClass(d).describe(ClassAnnotation.SUBCLASS_ROLE);
}
bugReporter.reportBug(bug);
} catch (ClassNotFoundException e) {
bugReporter.reportMissingClass(e);
}
} else if (hasCloneMethod && !isCloneable && !cloneOnlyThrowsException && !cloneIsDeprecated && !obj.isAbstract()) {
int priority = Priorities.NORMAL_PRIORITY;
if (referencesCloneMethod) {
priority--;
}
bugReporter.reportBug(new BugInstance(this, "CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE", priority).addClass(this)
.addMethod(cloneMethodAnnotation));
}
}
@Override
public void visit(ConstantNameAndType obj) {
String methodName = obj.getName(getConstantPool());
String methodSig = obj.getSignature(getConstantPool());
if (!methodName.equals("clone")) {
return;
}
if (!methodSig.startsWith("()")) {
return;
}
referencesCloneMethod = true;
}
@Override
public void visit(Method obj) {
if (obj.isAbstract() || BCELUtil.isSynthetic(obj)) {
return;
}
if (!obj.isPublic()) {
return;
}
if (!getMethodName().equals("clone")) {
return;
}
if (!getMethodSig().startsWith("()")) {
return;
}
hasCloneMethod = true;
cloneIsDeprecated = getXMethod().isDeprecated();
cloneMethodAnnotation = MethodAnnotation.fromVisitedMethod(this);
cloneOnlyThrowsException = PruneUnconditionalExceptionThrowerEdges.doesMethodUnconditionallyThrowException(XFactory
.createXMethod(this));
// ExceptionTable tbl = obj.getExceptionTable();
// throwsExceptions = tbl != null && tbl.getNumberOfExceptions() > 0;
}
/*
* (non-Javadoc)
*
* @see edu.umd.cs.findbugs.Detector#report()
*/
@Override
public void report() {
// do nothing
}
}