/*
 * 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.jvm.bytecode;

import gov.nasa.jpf.vm.ClassInfo;
import gov.nasa.jpf.vm.ClassLoaderInfo;
import gov.nasa.jpf.vm.ElementInfo;
import gov.nasa.jpf.vm.Instruction;
import gov.nasa.jpf.vm.LoadOnJPFRequired;
import gov.nasa.jpf.vm.MethodInfo;
import gov.nasa.jpf.vm.ThreadInfo;


/**
 * Invoke instance method; special handling for superclass, private,
 * and instance initialization method invocations
 * ..., objectref, [arg1, [arg2 ...]] => ...
 *
 * invokedMethod is supposed to be constant (ClassInfo can't change)
 */
public class INVOKESPECIAL extends InstanceInvocation {

  public INVOKESPECIAL (String clsDescriptor, String methodName, String signature){
    super(clsDescriptor, methodName, signature);
  }


  @Override
  public int getByteCode () {
    return 0xB7;
  }

  @Override
  public Instruction execute (ThreadInfo ti) {
    int argSize = getArgSize();
    int objRef = ti.getCalleeThis( argSize);
    lastObj = objRef;

    // we don't have to check for NULL objects since this is either a ctor, a 
    // private method, or a super method

    MethodInfo callee;  
    try {
      callee = getInvokedMethod(ti);
    } catch(LoadOnJPFRequired rre) {
      return ti.getPC();
    }      

    if (callee == null){
      return ti.createAndThrowException("java.lang.NoSuchMethodException", "Calling " + cname + '.' + mname);
    }

    ElementInfo ei = ti.getElementInfo(objRef);
    if (callee.isSynchronized()){
      ei = ti.getScheduler().updateObjectSharedness(ti, ei, null); // locks most likely belong to shared objects
      if (reschedulesLockAcquisition(ti, ei)){
        return this;
      }
    }

    setupCallee( ti, callee); // this creates, initializes and pushes the callee StackFrame

    return ti.getPC(); // we can't just return the first callee insn if a listener throws an exception
  }

  /**
   * 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;
  }

  /**
    * we can do some more caching here - the MethodInfo should be const
    */
  @Override
  public MethodInfo getInvokedMethod (ThreadInfo th) {

    // since INVOKESPECIAL is only used for private methods and ctors,
    // we don't have to deal with null object calls

    if (invokedMethod == null) {
      ClassInfo ci = ClassLoaderInfo.getCurrentResolvedClassInfo(cname);
      boolean recursiveLookup = (mname.charAt(0) != '<'); // no hierarchy lookup for <init>
      invokedMethod = ci.getMethod(mname, recursiveLookup);
    }

    return invokedMethod; // we can store internally
  }

  @Override
  public String toString() {
    return ("invokespecial " + cname + '.' + mname);
  }

  @Override
  public Object getFieldValue (String id, ThreadInfo ti) {
    int objRef = getCalleeThis(ti);
    ElementInfo ei = ti.getElementInfo(objRef);

    Object v = ei.getFieldValueObject(id);

    if (v == null){ // try a static field
      v = ei.getClassInfo().getStaticFieldValueObject(id);
    }

    return v;
  }

  @Override
  public void accept(JVMInstructionVisitor insVisitor) {
	  insVisitor.visit(this);
  }
}