/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2004-2005 Dave Brosius <dbrosius@users.sourceforge.net>
* Copyright (C) 2004-2005 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.BitSet;
import org.apache.bcel.classfile.Method;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.StatelessDetector;
/**
* looks for calls to Thread.interrupted from a non static context, especially
* when that context is not 'currentThread()'.
*/
public class SuspiciousThreadInterrupted extends BytecodeScanningDetector implements StatelessDetector {
public static final int SEEN_NOTHING = 0;
public static final int SEEN_CURRENTTHREAD = 1;
public static final int SEEN_POP_AFTER_CURRENTTHREAD = 2;
public static final int SEEN_UNKNOWNCONTEXT_POP = 3;
public static final int SEEN_POSSIBLE_THREAD = 4;
private BugReporter bugReporter;
private BitSet localsWithCurrentThreadValue;
private int state;
public SuspiciousThreadInterrupted(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public void visit(Method obj) {
localsWithCurrentThreadValue = new BitSet();
state = SEEN_NOTHING;
super.visit(obj);
}
@Override
public void sawOpcode(int seen) {
if (state == SEEN_POSSIBLE_THREAD) {
if (seen == POP) {
state = SEEN_UNKNOWNCONTEXT_POP;
return;
} else
state = SEEN_NOTHING;
}
switch (state) {
case SEEN_NOTHING:
if ((seen == INVOKESTATIC) && getClassConstantOperand().equals("java/lang/Thread")
&& getNameConstantOperand().equals("currentThread") && getSigConstantOperand().equals("()Ljava/lang/Thread;"))
state = SEEN_CURRENTTHREAD;
else if ((seen == INVOKESTATIC || seen == INVOKEINTERFACE || seen == INVOKEVIRTUAL || seen == INVOKESPECIAL)
&& getSigConstantOperand().endsWith("Ljava/lang/Thread;"))
state = SEEN_POSSIBLE_THREAD;
else if (seen == ALOAD) {
if (localsWithCurrentThreadValue.get(getRegisterOperand())) {
state = SEEN_CURRENTTHREAD;
} else
state = SEEN_POSSIBLE_THREAD;
} else if ((seen >= ALOAD_0) && (seen <= ALOAD_3)) {
if (localsWithCurrentThreadValue.get(seen - ALOAD_0)) {
state = SEEN_CURRENTTHREAD;
} else
state = SEEN_POSSIBLE_THREAD;
} else if ((seen == GETFIELD || seen == GETSTATIC) && getSigConstantOperand().equals("Ljava/lang/Thread;"))
state = SEEN_POSSIBLE_THREAD;
break;
case SEEN_CURRENTTHREAD:
if (seen == POP) {
state = SEEN_POP_AFTER_CURRENTTHREAD;
} else if (seen == ASTORE) {
localsWithCurrentThreadValue.set(getRegisterOperand());
state = SEEN_NOTHING;
} else if ((seen >= ASTORE_0) && (seen <= ASTORE_3)) {
localsWithCurrentThreadValue.set(seen - ASTORE_0);
state = SEEN_NOTHING;
} else {
state = SEEN_NOTHING;
}
break;
default:
if ((seen == INVOKESTATIC) && getClassConstantOperand().equals("java/lang/Thread")
&& getNameConstantOperand().equals("interrupted") && getSigConstantOperand().equals("()Z")) {
if (state == SEEN_POP_AFTER_CURRENTTHREAD) {
bugReporter.reportBug(new BugInstance(this, "STI_INTERRUPTED_ON_CURRENTTHREAD", LOW_PRIORITY)
.addClassAndMethod(this).addSourceLine(this));
} else if (state == SEEN_UNKNOWNCONTEXT_POP) {
bugReporter.reportBug(new BugInstance(this, "STI_INTERRUPTED_ON_UNKNOWNTHREAD", NORMAL_PRIORITY)
.addClassAndMethod(this).addSourceLine(this));
}
}
state = SEEN_NOTHING;
break;
}
}
}
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