/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 */

/*

 * 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.xpath.internal.Expression;

import com.sun.org.apache.xpath.internal.ExpressionOwner;

import com.sun.org.apache.xpath.internal.XPathVisitor;

import com.sun.org.apache.xpath.internal.functions.FuncLast;

import com.sun.org.apache.xpath.internal.functions.FuncPosition;

import com.sun.org.apache.xpath.internal.functions.Function;

import com.sun.org.apache.xpath.internal.objects.XNumber;

import com.sun.org.apache.xpath.internal.operations.Div;

import com.sun.org.apache.xpath.internal.operations.Minus;

import com.sun.org.apache.xpath.internal.operations.Mod;

import com.sun.org.apache.xpath.internal.operations.Mult;

import com.sun.org.apache.xpath.internal.operations.Plus;

import com.sun.org.apache.xpath.internal.operations.Quo;

import com.sun.org.apache.xpath.internal.operations.Variable;

@SuppressWarnings("deprecation")

public class HasPositionalPredChecker extends XPathVisitor

{

        private boolean m_hasPositionalPred = false;

        private int m_predDepth = 0;

        /**

         * Process the LocPathIterator to see if it contains variables

         * or functions that may make it context dependent.

         * @param path LocPathIterator that is assumed to be absolute, but needs checking.

         * @return true if the path is confirmed to be absolute, false if it

         * may contain context dependencies.

         */

        public static boolean check(LocPathIterator path)

        {

                HasPositionalPredChecker hppc = new HasPositionalPredChecker();

                path.callVisitors(null, hppc);

                return hppc.m_hasPositionalPred;

        }

        /**

         * Visit a function.

         * @param owner The owner of the expression, to which the expression can

         *              be reset if rewriting takes place.

         * @param func The function reference object.

         * @return true if the sub expressions should be traversed.

         */

        public boolean visitFunction(ExpressionOwner owner, Function func)

        {

                if((func instanceof FuncPosition) ||

                   (func instanceof FuncLast))

                        m_hasPositionalPred = true;

                return true;

        }

//      /**

//       * Visit a variable reference.

//       * @param owner The owner of the expression, to which the expression can

//       *              be reset if rewriting takes place.

//       * @param var The variable reference object.

//       * @return true if the sub expressions should be traversed.

//       */

//      public boolean visitVariableRef(ExpressionOwner owner, Variable var)

//      {

//              m_hasPositionalPred = true;

//              return true;

//      }

  /**

   * Visit a predicate within a location path.  Note that there isn't a

   * proper unique component for predicates, and that the expression will

   * be called also for whatever type Expression is.

   *

   * @param owner The owner of the expression, to which the expression can

   *              be reset if rewriting takes place.

   * @param pred The predicate object.

   * @return true if the sub expressions should be traversed.

   */

  public boolean visitPredicate(ExpressionOwner owner, Expression pred)

  {

    m_predDepth++;

    if(m_predDepth == 1)

    {

      if((pred instanceof Variable) ||

         (pred instanceof XNumber) ||

         (pred instanceof Div) ||

         (pred instanceof Plus) ||

         (pred instanceof Minus) ||

         (pred instanceof Mod) ||

         (pred instanceof Quo) ||

         (pred instanceof Mult) ||

         (pred instanceof com.sun.org.apache.xpath.internal.operations.Number) ||

         (pred instanceof Function))

          m_hasPositionalPred = true;

      else

        pred.callVisitors(owner, this);

    }

    m_predDepth--;

    // Don't go have the caller go any further down the subtree.

    return false;

  }

}