/*******************************************************************************
 * Copyright (c) 2008 IBM Corporation.
 * All rights reserved. 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
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package com.ibm.wala.core.tests.ptrs;

import java.io.IOException;
import java.util.Iterator;

import org.junit.Assert;
import org.junit.Test;

import com.ibm.wala.core.tests.callGraph.CallGraphTestUtil;
import com.ibm.wala.core.tests.util.TestConstants;
import com.ibm.wala.core.tests.util.WalaTestCase;
import com.ibm.wala.ipa.callgraph.AnalysisCache;
import com.ibm.wala.ipa.callgraph.AnalysisOptions;
import com.ibm.wala.ipa.callgraph.AnalysisScope;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.CallGraph;
import com.ibm.wala.ipa.callgraph.CallGraphBuilder;
import com.ibm.wala.ipa.callgraph.Entrypoint;
import com.ibm.wala.ipa.callgraph.impl.Util;
import com.ibm.wala.ipa.callgraph.propagation.InstanceKey;
import com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis;
import com.ibm.wala.ipa.callgraph.propagation.PointerKey;
import com.ibm.wala.ipa.cha.ClassHierarchy;
import com.ibm.wala.ipa.cha.ClassHierarchyException;
import com.ibm.wala.util.CancelException;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.intset.OrdinalSet;

public class TypeBasedArrayAliasTest extends WalaTestCase {

  @Test public void testTypeBasedArrayAlias() throws ClassHierarchyException, IllegalArgumentException, CancelException, IOException {
    AnalysisScope scope = CallGraphTestUtil.makeJ2SEAnalysisScope(TestConstants.WALA_TESTDATA, CallGraphTestUtil.REGRESSION_EXCLUSIONS);
    ClassHierarchy cha = ClassHierarchy.make(scope);
    Iterable<Entrypoint> entrypoints = com.ibm.wala.ipa.callgraph.impl.Util
        .makeMainEntrypoints(scope, cha, TestConstants.ARRAY_ALIAS_MAIN);
    AnalysisOptions options = CallGraphTestUtil.makeAnalysisOptions(scope, entrypoints);

    // RTA yields a TypeBasedPointerAnalysis
    CallGraphBuilder builder = Util.makeRTABuilder(options, new AnalysisCache(),cha, scope);
    CallGraph cg = builder.makeCallGraph(options, null);
    PointerAnalysis pa = builder.getPointerAnalysis();
    
    CGNode node = findNode(cg, "testMayAlias1");
    PointerKey pk1 = pa.getHeapModel().getPointerKeyForLocal(node, 1);
    PointerKey pk2 = pa.getHeapModel().getPointerKeyForLocal(node, 2);
    Assert.assertTrue(mayAliased(pk1, pk2, pa));
    
    node = findNode(cg, "testMayAlias2");
    pk1 = pa.getHeapModel().getPointerKeyForLocal(node, 1);
    pk2 = pa.getHeapModel().getPointerKeyForLocal(node, 2);
    Assert.assertTrue(mayAliased(pk1, pk2, pa));
    
    node = findNode(cg, "testMayAlias3");
    pk1 = pa.getHeapModel().getPointerKeyForLocal(node, 1);
    pk2 = pa.getHeapModel().getPointerKeyForLocal(node, 2);
    Assert.assertTrue(mayAliased(pk1, pk2, pa));
  }

  private final static CGNode findNode(CallGraph cg, String methodName) {
    for (Iterator<? extends CGNode> it = cg.iterator(); it.hasNext(); ) {
      CGNode n = it.next();
      if (n.getMethod().getName().toString().equals(methodName)) {
        return n;
      }
    }
    Assertions.UNREACHABLE("Unexpected: failed to find " + methodName + " node");
    return null;
  }

  private static boolean mayAliased(PointerKey pk1, PointerKey pk2, PointerAnalysis pa) {
    OrdinalSet<InstanceKey> ptsTo1 = pa.getPointsToSet(pk1);
    OrdinalSet<InstanceKey> ptsTo2 = pa.getPointsToSet(pk2);
    boolean foundIntersection = false;
    outer: for (InstanceKey i : ptsTo1) {
      for (InstanceKey j : ptsTo2) {
        if (i.equals(j)) {
          foundIntersection = true;
          break outer;
        }
      }
    }
    return foundIntersection;
  }

  
}
