/*

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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 com.sun.org.apache.xpath.internal.axes;

import com.sun.org.apache.xml.internal.dtm.Axis;

import com.sun.org.apache.xml.internal.utils.PrefixResolver;

import com.sun.org.apache.xpath.internal.compiler.Compiler;

/**

 * This class iterates over set of nodes that needs to be sorted.

 * @xsl.usage internal

 */

public class WalkingIteratorSorted extends WalkingIterator

{

    static final long serialVersionUID = -4512512007542368213L;

//  /** True if the nodes will be found in document order */

//  protected boolean m_inNaturalOrder = false;

  /** True if the nodes will be found in document order, and this can

   * be determined statically. */

  protected boolean m_inNaturalOrderStatic = false;

  /**

   * Create a WalkingIteratorSorted object.

   *

   * @param nscontext The namespace context for this iterator,

   * should be OK if null.

   */

  public WalkingIteratorSorted(PrefixResolver nscontext)

  {

    super(nscontext);

  }

  /**

   * Create a WalkingIterator iterator, including creation

   * of step walkers from the opcode list, and call back

   * into the Compiler to create predicate expressions.

   *

   * @param compiler The Compiler which is creating

   * this expression.

   * @param opPos The position of this iterator in the

   * opcode list from the compiler.

   * @param shouldLoadWalkers True if walkers should be

   * loaded, or false if this is a derived iterator and

   * it doesn't wish to load child walkers.

   *

   * @throws javax.xml.transform.TransformerException

   */

  WalkingIteratorSorted(

          Compiler compiler, int opPos, int analysis, boolean shouldLoadWalkers)

            throws javax.xml.transform.TransformerException

  {

    super(compiler, opPos, analysis, shouldLoadWalkers);

  }

  /**

   * Returns true if all the nodes in the iteration well be returned in document

   * order.

   *

   * @return true as a default.

   */

  public boolean isDocOrdered()

  {

    return m_inNaturalOrderStatic;

  }

  /**

   * Tell if the nodeset can be walked in doc order, via static analysis.

   *

   *

   * @return true if the nodeset can be walked in doc order, without sorting.

   */

  boolean canBeWalkedInNaturalDocOrderStatic()

  {

    if (null != m_firstWalker)

    {

      AxesWalker walker = m_firstWalker;

      int prevAxis = -1;

      boolean prevIsSimpleDownAxis = true;

      for(int i = 0; null != walker; i++)

      {

        int axis = walker.getAxis();

        if(walker.isDocOrdered())

        {

          boolean isSimpleDownAxis = ((axis == Axis.CHILD)

                                   || (axis == Axis.SELF)

                                   || (axis == Axis.ROOT));

          // Catching the filtered list here is only OK because

          // FilterExprWalker#isDocOrdered() did the right thing.

          if(isSimpleDownAxis || (axis == -1))

            walker = walker.getNextWalker();

          else

          {

            boolean isLastWalker = (null == walker.getNextWalker());

            if(isLastWalker)

            {

              if(walker.isDocOrdered() && (axis == Axis.DESCENDANT ||

                 axis == Axis.DESCENDANTORSELF || axis == Axis.DESCENDANTSFROMROOT

                 || axis == Axis.DESCENDANTSORSELFFROMROOT) || (axis == Axis.ATTRIBUTE))

                return true;

            }

            return false;

          }

        }

        else

          return false;

      }

      return true;

    }

    return false;

  }

//  /**

//   * NEEDSDOC Method canBeWalkedInNaturalDocOrder

//   *

//   *

//   * NEEDSDOC (canBeWalkedInNaturalDocOrder) @return

//   */

//  boolean canBeWalkedInNaturalDocOrder()

//  {

//

//    if (null != m_firstWalker)

//    {

//      AxesWalker walker = m_firstWalker;

//      int prevAxis = -1;

//      boolean prevIsSimpleDownAxis = true;

//

//      for(int i = 0; null != walker; i++)

//      {

//        int axis = walker.getAxis();

//

//        if(walker.isDocOrdered())

//        {

//          boolean isSimpleDownAxis = ((axis == Axis.CHILD)

//                                   || (axis == Axis.SELF)

//                                   || (axis == Axis.ROOT));

//          // Catching the filtered list here is only OK because

//          // FilterExprWalker#isDocOrdered() did the right thing.

//          if(isSimpleDownAxis || (axis == -1))

//            walker = walker.getNextWalker();

//          else

//          {

//            boolean isLastWalker = (null == walker.getNextWalker());

//            if(isLastWalker)

//            {

//              if(walker.isDocOrdered() && (axis == Axis.DESCENDANT ||

//                 axis == Axis.DESCENDANTORSELF || axis == Axis.DESCENDANTSFROMROOT

//                 || axis == Axis.DESCENDANTSORSELFFROMROOT) || (axis == Axis.ATTRIBUTE))

//                return true;

//            }

//            return false;

//          }

//        }

//        else

//          return false;

//      }

//      return true;

//    }

//    return false;

//  }

  /**

   * This function is used to perform some extra analysis of the iterator.

   *

   * @param vars List of QNames that correspond to variables.  This list

   * should be searched backwards for the first qualified name that

   * corresponds to the variable reference qname.  The position of the

   * QName in the vector from the start of the vector will be its position

   * in the stack frame (but variables above the globalsTop value will need

   * to be offset to the current stack frame).

   */

  {

    super.fixupVariables(vars, globalsSize);

    int analysis = getAnalysisBits();

    if(WalkerFactory.isNaturalDocOrder(analysis))

    {

        m_inNaturalOrderStatic = true;

    }

    else

    {

        m_inNaturalOrderStatic = false;

        // System.out.println("Setting natural doc order to false: "+

        //    WalkerFactory.getAnalysisString(analysis));

    }

  }

}