/******************************************************************************
 * Copyright (c) 2002 - 2006 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.cast.ipa.callgraph;

import java.util.Iterator;
import java.util.Set;

import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.Context;
import com.ibm.wala.ipa.callgraph.ContextSelector;
import com.ibm.wala.ipa.callgraph.propagation.InstanceKey;
import com.ibm.wala.ipa.cha.IClassHierarchy;
import com.ibm.wala.types.ClassLoaderReference;
import com.ibm.wala.types.Descriptor;
import com.ibm.wala.types.MethodReference;
import com.ibm.wala.types.TypeName;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.Atom;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.debug.Trace;

public class MiscellaneousHacksContextSelector implements ContextSelector {

  private final Set<MethodReference> methodsToSpecialize;

  private final ContextSelector specialPolicy;

  private final ContextSelector basePolicy;

  public MiscellaneousHacksContextSelector(ContextSelector special, ContextSelector base, IClassHierarchy cha,
      String[][] descriptors) {
    basePolicy = base;
    specialPolicy = special;
    methodsToSpecialize = HashSetFactory.make();
    for (int i = 0; i < descriptors.length; i++) {
      String[] descr = descriptors[i];
      switch (descr.length) {

      // loader name, loader language, classname, method name, method descr
      case 5: {
        MethodReference ref = MethodReference.findOrCreate(TypeReference.findOrCreate(new ClassLoaderReference(Atom
            .findOrCreateUnicodeAtom(descr[0]), Atom.findOrCreateUnicodeAtom(descr[1])), TypeName.string2TypeName(descr[2])), Atom
            .findOrCreateUnicodeAtom(descr[3]), Descriptor.findOrCreateUTF8(descr[4]));

        if (cha.resolveMethod(ref) != null) {
          methodsToSpecialize.add(cha.resolveMethod(ref).getReference());
        } else {
          methodsToSpecialize.add(ref);
        }
        break;
      }

        // classname, method name, method descr
      case 3: {
        MethodReference ref = MethodReference.findOrCreate(TypeReference.findOrCreate(new ClassLoaderReference(Atom
            .findOrCreateUnicodeAtom("Application"), ClassLoaderReference.Java), TypeName.string2TypeName(descr[0])), Atom
            .findOrCreateUnicodeAtom(descr[1]), Descriptor.findOrCreateUTF8(descr[2]));

        methodsToSpecialize.add(cha.resolveMethod(ref).getReference());
        break;
      }

        // loader name, classname, meaning all methods of that class
      case 2: {
        IClass klass = cha.lookupClass(TypeReference.findOrCreate(new ClassLoaderReference(Atom.findOrCreateUnicodeAtom(descr[0]),
            ClassLoaderReference.Java), TypeName.string2TypeName(descr[1])));

        for (Iterator M = klass.getDeclaredMethods().iterator(); M.hasNext();) {
          methodsToSpecialize.add(((IMethod) M.next()).getReference());
        }

        break;
      }

        // classname, meaning all methods of that class
      case 1: {
        IClass klass = cha.lookupClass(TypeReference.findOrCreate(new ClassLoaderReference(Atom
            .findOrCreateUnicodeAtom("Application"), ClassLoaderReference.Java), TypeName.string2TypeName(descr[0])));

        for (Iterator M = klass.getDeclaredMethods().iterator(); M.hasNext();) {
          methodsToSpecialize.add(((IMethod) M.next()).getReference());
        }

        break;
      }

      default:
        Assertions.UNREACHABLE();
      }
    }

    Trace.println("hacking context selector for methods " + methodsToSpecialize);
  }

  public Context getCalleeTarget(CGNode caller, CallSiteReference site, IMethod callee, InstanceKey receiver) {
    if (methodsToSpecialize.contains(site.getDeclaredTarget()) || methodsToSpecialize.contains(callee.getReference())) {
      return specialPolicy.getCalleeTarget(caller, site, callee, receiver);
    } else {
      return basePolicy.getCalleeTarget(caller, site, callee, receiver);
    }
  }

  public boolean contextIsIrrelevant(CGNode node, CallSiteReference site) {
    return basePolicy.contextIsIrrelevant(node, site);
  }

  public int getBoundOnNumberOfTargets(CGNode caller, CallSiteReference reference, IMethod targetMethod) {
    return -1;
  }

  public boolean mayUnderstand(CGNode caller, CallSiteReference site, IMethod targetMethod, InstanceKey instance) {
    return true;
  }

  public boolean allSitesDispatchIdentically(CGNode node, CallSiteReference site) {
    return false;
  }
}