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-serv4247/src/com/mebigfatguy/fbcontrib/detect

Added Files:
	AbnormalFinallyBlockReturn.java 
Log Message:
new detector, AFBR - initial checkin

--- NEW FILE: AbnormalFinallyBlockReturn.java ---
package com.mebigfatguy.fbcontrib.detect;

import java.util.ArrayList;
import java.util.List;

import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.CodeException;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.StatelessDetector;

public class AbnormalFinallyBlockReturn extends BytecodeScanningDetector implements StatelessDetector {
	private BugReporter bugReporter;
	private CodeException[] exc;
	private List<FinallyBlockInfo> fbInfo = new ArrayList<FinallyBlockInfo>();
	
	public AbnormalFinallyBlockReturn(final BugReporter bugReporter) {
		this.bugReporter = bugReporter;
	}
	
	public Object clone() throws CloneNotSupportedException {
		return super.clone();
	}
		
	public void visitCode(Code obj) {
		fbInfo.clear();
		exc = obj.getExceptionTable();
		if (exc != null) {
			for (CodeException ce : exc) {
				if ((ce.getCatchType() == 0)
				&&  (ce.getStartPC() == ce.getHandlerPC())) {
					fbInfo.add(new FinallyBlockInfo(ce.getStartPC(), ce.getEndPC()));
				}
			}
		}
		
		if (fbInfo.size() > 0)
			super.visitCode(obj);
	}
	
	public void sawOpcode(int seen) {
		if (fbInfo.size() == 0)
			return;
		
		FinallyBlockInfo fbi = fbInfo.get(0);
		
		if ((seen == GOTO) && ((getPC() + 3) == fbi.startPC)) {
			fbi.afterFinallyPC = getBranchTarget();
			return;
		} else if ((seen == ATHROW) && ((getPC() + 1) == fbi.startPC)) {
			fbi.afterFinallyPC = getMaxPC() + 1;
			return;
		}
		
		if (getPC() < fbi.startPC)
			return;
		
		if ((getPC() == fbi.startPC) && (fbi.afterFinallyPC == 0)) {
			fbInfo.remove(0);
			sawOpcode(seen);
			return;
		}
					
		if (getPC() >= fbi.afterFinallyPC) {
			fbInfo.remove(0);
			sawOpcode(seen);
			return;
		}
		
		if (seen == MONITORENTER) {
			fbi.monitorCount++;
		} else if (seen == MONITOREXIT) {
			fbi.monitorCount--;
			if (fbi.monitorCount < 0) {
				fbInfo.remove(0);
				sawOpcode(seen);
				return;
			}
		}
		
		if (((seen >= IRETURN) && (seen <= RETURN)) || (seen == ATHROW)) {
			bugReporter.reportBug(new BugInstance( this, "AFBR_ABNORMAL_FINALLY_BLOCK_RETURN", NORMAL_PRIORITY)
					.addClass(this)
					.addMethod(this)
					.addSourceLine(this));
			fbInfo.remove(0);
		}
	}
	
	public static class FinallyBlockInfo
	{
		public int startPC;
		public int endPC;
		public int afterFinallyPC;
		public int monitorCount;
		
		public FinallyBlockInfo(int start, int end) {
			startPC = start;
			endPC = end;
			afterFinallyPC = 0;
			monitorCount = 0;
		}
	}
}