/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2003, 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;
import java.util.*;
import java.io.PrintStream;
import org.apache.bcel.classfile.*;
import java.util.zip.*;
import java.io.*;

import edu.umd.cs.pugh.visitclass.DismantleBytecode;
import edu.umd.cs.pugh.visitclass.Constants2;

public class MutableLock extends BytecodeScanningDetector implements   Constants2 {
    HashSet setFields = new HashSet();
    boolean thisOnTOS = false;
    private BugReporter bugReporter;

  public MutableLock(BugReporter bugReporter) {
	this.bugReporter = bugReporter;
  }

  public void visit(JavaClass obj)     {
	super.visit(obj);
	}

    public void visit(Method obj) {
        super.visit(obj);
	setFields.clear();
        thisOnTOS = false;
	}


    public void sawOpcode(int seen) {

	switch (seen) {
	case ALOAD_0:
		thisOnTOS = true;
		return;
	case MONITOREXIT:
		setFields.clear();
		break;
	case PUTFIELD:
		if (classConstant == className) 
			setFields.add(nameConstant);
		break;
	case GETFIELD: 
		if (thisOnTOS && classConstant == className
			&& setFields.contains(nameConstant)
			&& asUnsignedByte(codeBytes[PC+3]) == DUP
			&& asUnsignedByte(codeBytes[PC+5]) == MONITORENTER
			) 
		  bugReporter.reportBug(new BugInstance("ML_SYNC_ON_UPDATED_FIELD", NORMAL_PRIORITY)
			.addClassAndMethod(this)
			.addReferencedField(this));
		break;
	default: 
	}
        thisOnTOS = false;
	}	
}

@@ -2134,16 +2134,48 @@
 ld(this)
+%0A%09%09%09.addSourceLine(this, PC + 5)
 );%0A%09%09bre

Add a source line annotation for the monitorenter.