//
// Copyright (C) 2006 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA).  All Rights Reserved.
// 
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3.  The NOSA has been approved by the Open Source
// Initiative.  See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
// 
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
package gov.nasa.jpf.jvm.bytecode;

import gov.nasa.jpf.jvm.*;


/**
 * common root for MONITORENTER/EXIT
 */
public abstract class LockInstruction extends Instruction {
  int lastLockRef = -1;

  /**
    * only useful post-execution (in an instructionExecuted() notification)
    */
  public int getLastLockRef () {
    return lastLockRef;
  }
  
  /**
   * If the current thread already owns the lock, then the current thread can go on.
   * For example, this is a recursive acquisition.
   */
  protected boolean isLockOwner(ThreadInfo ti, ElementInfo ei) {
    return ei.getLockingThread() == ti;
  }
  
  /**
   * If the object will still be owned, then the current thread can go on.
   * For example, all but the last monitorexit for the object.
   */
  protected boolean isLastUnlock(ElementInfo ei) {
    return ei.getLockCount() == 1;
  }
  
  /**
   * If the object isn't shared, then the current thread can go on.
   * For example, this object isn't reachable by other threads.
   */
  protected boolean isShared(ThreadInfo ti, ElementInfo ei) {
    if (!ti.skipLocalSync()) {
      return true;
    }
    
    return ei.isShared();
  }

  public void accept(InstructionVisitor insVisitor) {
	  insVisitor.visit(this);
  }
}

@@ -1775,17 +1775,17 @@
 nt() == 
-1
+0
 ;%0A  %7D%0A  

Fix bug in LockInstruction.isLastUnlock() to test against 0 instead of 1 since the method is called after decrementing the lock count.