fb-contrib-commit

[Dave B. <dbr...@us...>]

Update of /cvsroot/fb-contrib/fb-contrib/src/com/mebigfatguy/fbcontrib/detect
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv19962/src/com/mebigfatguy/fbcontrib/detect

Added Files:
	BloatedSynchronizedBlock.java 
Log Message:
initial checkin - BSB -- not working yet, so hidden

--- NEW FILE: BloatedSynchronizedBlock.java ---
/*
 * fb-contrib - Auxilliary detectors for Java programs
 * Copyright (C) 2005 Dave Brosius
 * 
 * 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 com.mebigfatguy.fbcontrib.detect;

import org.apache.bcel.Constants;
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.OpcodeStack;
import edu.umd.cs.findbugs.StatelessDetector;

public class BloatedSynchronizedBlock extends BytecodeScanningDetector implements StatelessDetector
{
	private BugReporter bugReporter;
	private static final String BSB_MIN_SAFE_CODE_SIZE = "fb-contrib.bsb.minsize";
	private OpcodeStack stack = new OpcodeStack();
	private int syncPC;
	private int lastPC;
	private int startSafe;
	private boolean isStatic;
	private int minSafeCodeLength;	
	
    /**
     * constructs a BSB detector given the reporter to report bugs on

     * @param bugReporter the sync of bug reports
     */		
	public BloatedSynchronizedBlock(BugReporter bugReporter) {
		this.bugReporter = bugReporter;
		minSafeCodeLength = Integer.getInteger(BSB_MIN_SAFE_CODE_SIZE, 10);
	}
	
 	/**
 	 * clone this detector so that it can be a StatelessDetector
 	 * 
 	 * @return a clone of this object
 	 */    
	public Object clone() throws CloneNotSupportedException {
		return super.clone();
	}
	
	/**
	 * implement the visitor to reset the sync count, the stack, and gather some information
	 * 
	 * @param obj the context object for the currently parsed method
	 */
	@Override
	public void visitMethod(Method obj) {
		if (obj.isSynchronized())
			syncPC = 0;
		else
			syncPC = -1;
		stack.resetForMethodEntry(this);
		startSafe = 0;
		lastPC = -1;
		isStatic = obj.isStatic();
	}
	
	/** 
	 * implement the visitor to find bloated sync blocks. This implementation
	 * only checks the outer most block
	 * 
	 * @param seen the opcode of the currently parsed instruction
	 */
	public void sawOpcode(int seen) {
		try {
			if ("BSB_Sample".equals(getClassName()))
				System.out.println(Constants.OPCODE_NAMES[seen]);
			if (seen == MONITORENTER) {
				if (syncPC < 0) {
					syncPC = getPC();
					startSafe = this.getNextPC();
				}
			}
			else if (seen == MONITOREXIT) {
				if ((startSafe >= 0) && ((getPC() - startSafe) > minSafeCodeLength)) {
					bugReporter.reportBug(new BugInstance(this, "BSB_BLOATED_SYNCHRONIZED_BLOCK", NORMAL_PRIORITY)
									.addClass(this)
									.addMethod(this)
									.addSourceLineRange(this, startSafe, lastPC));
				}
				syncPC = -1;
				startSafe = -1;
			}
			else {
				boolean unsafe = ((seen == PUTFIELD) || (seen == GETFIELD));
				unsafe |= (!isStatic) && ((seen == ALOAD_0) || (seen == ASTORE_0));
				if (unsafe) {
					if (syncPC >= 0) {
						if ((getPC() - startSafe) > minSafeCodeLength) {
							bugReporter.reportBug(new BugInstance(this, "BSB_BLOATED_SYNCHRONIZED_BLOCK", NORMAL_PRIORITY)
											.addClass(this)
											.addMethod(this)
											.addSourceLineRange(this, startSafe, lastPC));
						}
					}
					startSafe = -1;
					syncPC = -1;
				} else if (startSafe < 0) {
					int depth = stack.getStackDepth();
					int i;
					for (i = 0; i < depth; i++) {
						OpcodeStack.Item item = stack.getStackItem(i);
						if (item.getField() != null) {
							break;
						}
					}
					if (i == depth)
						startSafe = getPC();
				}
			}
			lastPC = getPC();
		} finally {
			stack.sawOpcode(this, seen);
		}
	}
}