/*
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 * 
 * This file is a derivative of code released under the terms listed below.  
 *
 */
/**
 *
 * Copyright (c) 2009-2012,
 *
 *  Galois, Inc. (Aaron Tomb <atomb@galois.com>, 
 *                Rogan Creswick <creswick@galois.com>, 
 *                Adam Foltzer <acfoltzer@galois.com>)
 *  Steve Suh    <suhsteve@gmail.com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. The names of the contributors may not be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *
 */
package org.scandroid.flow.functions;

import java.util.Map;
import java.util.Set;

import org.scandroid.domain.CodeElement;
import org.scandroid.domain.DomainElement;
import org.scandroid.domain.IFDSTaintDomain;
import org.scandroid.domain.InstanceKeyElement;
import org.scandroid.domain.LocalElement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.ibm.wala.dataflow.IFDS.IUnaryFlowFunction;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.propagation.InstanceKey;
import com.ibm.wala.ipa.callgraph.propagation.LocalPointerKey;
import com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis;
import com.ibm.wala.ipa.callgraph.propagation.PointerKey;
import com.ibm.wala.ssa.ISSABasicBlock;
import com.ibm.wala.util.collections.HashMapFactory;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.MutableSparseIntSet;

/**
 * Propagates heap information from InstanceKeys to the LocalElements that point
 * to those keys
 * 
 * @author acfoltzer
 * 
 * @param <E>
 */
public class GlobalReturnToNodeFunction<E extends ISSABasicBlock> implements
		IUnaryFlowFunction {
	private static final Logger logger = LoggerFactory
			.getLogger(GlobalReturnToNodeFunction.class);

	private final IFDSTaintDomain<E> domain;
	private final Map<InstanceKey, Set<CodeElement>> ikMap;

	public GlobalReturnToNodeFunction(IFDSTaintDomain<E> domain,
			PointerAnalysis<InstanceKey> pa, CGNode node) {
		this.domain = domain;
		this.ikMap = HashMapFactory.make();
		for (PointerKey pk : pa.getPointerKeys()) {
			if (!(pk instanceof LocalPointerKey)) {
				continue;
			}
			LocalPointerKey lpk = (LocalPointerKey) pk;
			if (!lpk.getNode().equals(node)) {
				continue;
			}
			for (InstanceKey ik : pa.getPointsToSet(lpk)) {
				Set<CodeElement> elts = ikMap.get(ik);
				if (null == elts) {
					elts = HashSetFactory.make();
					ikMap.put(ik, elts);
				}
				elts.add(new LocalElement(lpk.getValueNumber()));
			}
		}
	}

	@Override
	public IntSet getTargets(int d) {
		MutableSparseIntSet set = MutableSparseIntSet.makeEmpty();
		if (0 == d) {
			set.add(d);
		} else {
			DomainElement de = domain.getMappedObject(d);
			if (de.codeElement instanceof InstanceKeyElement) {
				InstanceKey ik = ((InstanceKeyElement) de.codeElement)
						.getInstanceKey();
				Set<CodeElement> elts = ikMap.get(ik);
				if (null != elts) {
					for (CodeElement elt : elts) {
						set.add(domain.getMappedIndex(new DomainElement(elt,
								de.taintSource)));
					}
				}
			} else {
				logger.debug("throwing away {}", de);
			}
		}
		return set;
	}

}