/*
* 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.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.MONITORENTER;
import org.apache.bcel.generic.MethodGen;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.SourceLineAnnotation;
import edu.umd.cs.findbugs.StatelessDetector;
import edu.umd.cs.findbugs.ba.CFG;
import edu.umd.cs.findbugs.ba.CFGBuilderException;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.Hierarchy;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.LockDataflow;
public final class FindTwoLockWait implements Detector, StatelessDetector {
private final BugReporter bugReporter;
private JavaClass javaClass;
private final Collection<BugInstance> possibleWaitBugs = new LinkedList<BugInstance>();
private final Collection<SourceLineAnnotation> possibleNotifyLocations = new LinkedList<SourceLineAnnotation>();
public FindTwoLockWait(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new AssertionError(e);
}
}
@Override
public void visitClassContext(ClassContext classContext) {
javaClass = classContext.getJavaClass();
possibleWaitBugs.clear();
possibleNotifyLocations.clear();
Method[] methodList = javaClass.getMethods();
for (Method method : methodList) {
MethodGen methodGen = classContext.getMethodGen(method);
if (methodGen == null) {
continue;
}
if (!preScreen(methodGen)) {
continue;
}
try {
analyzeMethod(classContext, method);
} catch (DataflowAnalysisException e) {
// bugReporter.logError("Error analyzing " + method.toString(),
// e);
} catch (CFGBuilderException e) {
bugReporter.logError("Error analyzing " + method.toString(), e);
}
}
if (!possibleNotifyLocations.isEmpty()) {
for (BugInstance bug : possibleWaitBugs) {
for (SourceLineAnnotation notifyLine : possibleNotifyLocations) {
bug.addSourceLine(notifyLine).describe("SOURCE_NOTIFICATION_DEADLOCK");
}
bugReporter.reportBug(bug);
}
}
}
private void analyzeMethod(ClassContext classContext, Method method) throws CFGBuilderException, DataflowAnalysisException {
MethodGen methodGen = classContext.getMethodGen(method);
CFG cfg = classContext.getCFG(method);
LockDataflow dataflow = classContext.getLockDataflow(method);
for (Iterator<Location> j = cfg.locationIterator(); j.hasNext();) {
Location location = j.next();
visitLocation(classContext, location, methodGen, dataflow);
}
}
public boolean preScreen(MethodGen mg) {
ConstantPoolGen cpg = mg.getConstantPool();
int lockCount = mg.isSynchronized() ? 1 : 0;
boolean sawWaitOrNotify = false;
InstructionHandle handle = mg.getInstructionList().getStart();
while (handle != null && !(lockCount >= 2 && sawWaitOrNotify)) {
Instruction ins = handle.getInstruction();
if (ins instanceof MONITORENTER) {
++lockCount;
} else if (ins instanceof INVOKEVIRTUAL) {
INVOKEVIRTUAL inv = (INVOKEVIRTUAL) ins;
String methodName = inv.getMethodName(cpg);
if (methodName.equals("wait") || methodName.startsWith("notify")) {
sawWaitOrNotify = true;
}
}
handle = handle.getNext();
}
return lockCount >= 2 && sawWaitOrNotify;
}
public void visitLocation(ClassContext classContext, Location location, MethodGen methodGen, LockDataflow dataflow)
throws DataflowAnalysisException {
ConstantPoolGen cpg = methodGen.getConstantPool();
if (Hierarchy.isMonitorWait(location.getHandle().getInstruction(), cpg)) {
int count = dataflow.getFactAtLocation(location).getNumLockedObjects();
if (count > 1) {
// A wait with multiple locks held?
String sourceFile = javaClass.getSourceFileName();
possibleWaitBugs.add(new BugInstance(this, "TLW_TWO_LOCK_WAIT", HIGH_PRIORITY).addClassAndMethod(methodGen,
sourceFile).addSourceLine(classContext, methodGen, sourceFile, location.getHandle()));
}
}
if (Hierarchy.isMonitorNotify(location.getHandle().getInstruction(), cpg)) {
int count = dataflow.getFactAtLocation(location).getNumLockedObjects();
if (count > 1) {
// A notify with multiple locks held?
String sourceFile = javaClass.getSourceFileName();
possibleNotifyLocations.add(SourceLineAnnotation.fromVisitedInstruction(classContext, methodGen, sourceFile,
location.getHandle()));
}
}
}
@Override
public void report() {
}
}