[Fb-contrib-commit] fb-contrib/src/com/mebigfatguy/fbcontrib/detect OrphanedDOMNode.java,NONE,1.1

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Update of /cvsroot/fb-contrib/fb-contrib/src/com/mebigfatguy/fbcontrib/detect
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv22247/src/com/mebigfatguy/fbcontrib/detect

Added Files:
	OrphanedDOMNode.java 
Log Message:
initial checkin: new ODN detector

--- NEW FILE: OrphanedDOMNode.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 java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.apache.bcel.classfile.Code;

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 OrphanedDOMNode extends BytecodeScanningDetector implements StatelessDetector 
{
	private static final Set<String> domCreationMethods = new HashSet<String>();
	private static final Set<String> domAppendMethods = new HashSet<String>();
	static {
		domCreationMethods.add("createAttribute:(Ljava/lang/String;)Lorg/w3c/dom/Attr;");
		domCreationMethods.add("createAttributeNS:(Ljava/lang/String;Ljava/lang/String;)Lorg/w3c/dom/Attr;");
		domCreationMethods.add("createCDATASection:(Ljava/lang/String;)Lorg/w3c/dom/CDATASection;");
		domCreationMethods.add("createComment:(Ljava/lang/String;)Lorg/w3c/dom/Comment;");
		domCreationMethods.add("createElement:(Ljava/lang/String;)Lorg/w3c/dom/Element;");
		domCreationMethods.add("createElementNS:(Ljava/lang/String;Ljava/lang/String;)Lorg/w3c/dom/Element;");
		domCreationMethods.add("createProcessingInstruction:(Ljava/lang/String;Ljava/lang/String;)Lorg/w3c/dom/ProcessingInstruction;");
		domCreationMethods.add("createTextNode:(Ljava/lang/String;)Lorg/w3c/dom/Text;");
		
		domAppendMethods.add("appendChild:(Lorg/w3c/dom/Node;)Lorg/w3c/dom/Node;");
		domAppendMethods.add("setAttributeNode:(Lorg/w3c/dom/Attr;)Lorg/w3c/dom/Attr;");
		domAppendMethods.add("setAttributeNodeNS:(Lorg/w3c/dom/Attr;)Lorg/w3c/dom/Attr;");
	}
	
	private BugReporter bugReporter;
	private OpcodeStack stack = new OpcodeStack();
	private Map<OpcodeStack.Item, Integer> nodeCreations = new HashMap<OpcodeStack.Item, Integer>();
	private Map<Integer, Integer> nodeStores = new HashMap<Integer, Integer>();
	
    /**
     * constructs a ODN detector given the reporter to report bugs on

     * @param bugReporter the sync of bug reports
     */	
	public OrphanedDOMNode(BugReporter bugReporter) {
		this.bugReporter = bugReporter;
	}
	
 	/**
 	 * clone this detector so that it can be a StatelessDetector
 	 * 
 	 * @return a clone of this object
 	 */    
	@Override
	public Object clone() throws CloneNotSupportedException {
		return super.clone();
	}
	
	/**
	 * implements the visitor to clear the opcode stack for the next code
	 * 
	 * @param obj the context object for the currently parsed code block
	 */
	public void visitCode(Code obj) {
		stack.resetForMethodEntry(this);
		nodeCreations.clear();
		nodeStores.clear();
		super.visitCode(obj);
		
		Set<Integer> reportedPCs = new HashSet<Integer>();
		for (Integer pc : nodeCreations.values()) {
			if (!reportedPCs.contains(pc)) {
				bugReporter.reportBug(new BugInstance(this, "ODN_ORPHANED_DOM_NODE", NORMAL_PRIORITY)
												.addClass(this)
												.addMethod(this)
												.addSourceLine(this, pc.intValue()));
				reportedPCs.add(pc);
			}
		}
		for (Integer pc : nodeStores.values()) {
			if (!reportedPCs.contains(pc)) {
				bugReporter.reportBug(new BugInstance(this, "ODN_ORPHANED_DOM_NODE", NORMAL_PRIORITY)
												.addClass(this)
												.addMethod(this)
												.addSourceLine(this, pc.intValue()));
				reportedPCs.add(pc);
			}
		}
	}
	
	/**
	 * implements the visitor to find DOM based nodes that are allocated but not appended to
	 * an existing node (or returned).
	 * 
	 * @param seen the currently parsed opcode
	 */
	public void sawOpcode(int seen) {
		boolean sawCreate = false;
		Integer itemPC = null;
		
		try {
			if (seen == INVOKEINTERFACE) {
				String className = getClassConstantOperand();
				String methodInfo = getNameConstantOperand() + ":" + getSigConstantOperand();
				if ("org/w3c/dom/Document".equals(className)) {
					if (domCreationMethods.contains(methodInfo)) {
						sawCreate = true;
						itemPC = new Integer(getPC());
					}
				}
				if (!sawCreate) {
					if (domAppendMethods.contains(methodInfo)) {
						if (stack.getStackDepth() > 0) {
							OpcodeStack.Item itm = stack.getStackItem(0);
							int reg = itm.getRegisterNumber();
							nodeCreations.remove(itm);
							nodeStores.remove(reg);
						}
					}
				}
			} else if ((seen == ASTORE) || ((seen >= ASTORE_0) && seen <= ASTORE_3)) {
				Integer pc = findDOMNodeCreationPoint(0);
				int reg;
				if (seen == ASTORE)
					reg = getRegisterOperand();
				else
					reg = seen - ASTORE_0;
				if (pc != null)
					nodeStores.put(new Integer(reg), pc);
				else
					nodeStores.remove(new Integer(reg));
			} else if (seen == PUTFIELD) {
				//Stores to member variables are assumed ok
				findDOMNodeCreationPoint(0);
			} else if ((seen == ALOAD) || ((seen >= ALOAD_0) && (seen <= ALOAD_3))) {
				int reg;
				if (seen == ALOAD)
					reg = getRegisterOperand();
				else
					reg = seen - ALOAD_0;
				itemPC = nodeStores.get(new Integer(reg));
				if (itemPC != null)
					sawCreate = true;
			} else if (seen == ARETURN) {
				if (stack.getStackDepth() > 0) {
					OpcodeStack.Item itm = stack.getStackItem(0);
					int reg = itm.getRegisterNumber();
					nodeCreations.remove(itm);
					nodeStores.remove(new Integer(reg));
				}
			}
		} finally {
			stack.sawOpcode(this, seen);
			if (sawCreate) {
				if (stack.getStackDepth() > 0)
					nodeCreations.put(stack.getStackItem(0), itemPC);
			}
		}
	}
	
	/**
	 * returns the pc where this DOM Node was created, or null if this isn't a DOM node that was created
	 * 
	 * @param index the index into the stack of the item to be checked
	 * 
	 * @return the pc where this NODE was created, or null
	 */
	private Integer findDOMNodeCreationPoint(int index) {
		if (stack.getStackDepth() > index)
			return nodeCreations.remove(stack.getStackItem(index));

		return null;
	}
}