/*
 * Copyright (C) 2014, United States Government, as represented by the
 * Administrator of the National Aeronautics and Space Administration.
 * All rights reserved.
 *
 * The Java Pathfinder core (jpf-core) platform is licensed under the
 * Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 *        http://www.apache.org/licenses/LICENSE-2.0. 
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 */
package gov.nasa.jpf.vm;


/**
 * NOTE - making VMStates fully restorable is currently very
 * expensive and should only be done on a selective basis
 */
public class RestorableVMState {
  
  /** the set of last executed insns */
  Transition lastTransition;
  
  /* these are the icky parts - the history is kept as stacks inside the
   * VM (for restoration reasons), hence we have to copy it if we want
   * to restore a state. Since this is really expensive, it has to be done
   * on demand, with varying degrees of information
   */
  Path path;
  
  Backtracker.RestorableState bkstate;
  
  VM vm;
  
  RestorableVMState (VM vm) {
    this.vm = vm;

    path = vm.getClonedPath();
    bkstate = vm.getBacktracker().getRestorableState();
    lastTransition = vm.lastTrailInfo;
  }
  
  public Backtracker.RestorableState getBkState() {
    return bkstate;
  }
  
  public Transition getLastTransition () {
    return lastTransition;
  }
  
  public Path getPath () {
    return path;
  }
  
  public int getThread () {
    return lastTransition.getThreadIndex();
  }

}