compiler.java

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/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact [e-mail].
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 * 5. Products derived from this software may not be called "Apache",
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xpath.compiler;

import org.apache.xpath.operations.And;
import org.apache.xpath.operations.Bool;
import org.apache.xpath.operations.Div;
import org.apache.xpath.operations.Equals;
import org.apache.xpath.operations.Gt;
import org.apache.xpath.operations.Gte;
import org.apache.xpath.operations.Lt;
import org.apache.xpath.operations.Lte;
import org.apache.xpath.operations.Minus;
import org.apache.xpath.operations.Mod;
import org.apache.xpath.operations.Mult;
import org.apache.xpath.operations.Neg;
import org.apache.xpath.operations.NotEquals;
import org.apache.xpath.operations.Operation;
import org.apache.xpath.operations.Or;
import org.apache.xpath.operations.Plus;
import org.apache.xpath.operations.UnaryOperation;
import org.apache.xpath.operations.Variable;
import org.apache.xpath.objects.*;
import org.apache.xpath.axes.*;
import org.apache.xpath.patterns.*;
import org.apache.xpath.functions.Function;
import org.apache.xpath.functions.FuncExtFunction;
import org.apache.xpath.functions.WrongNumberArgsException;
import org.apache.xpath.*;
import org.apache.xpath.res.XPATHErrorResources;
import org.apache.xalan.res.XSLMessages;
import org.apache.xml.utils.QName;
import org.apache.xml.utils.PrefixResolver;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.SourceLocator;
import org.apache.xml.utils.SAXSourceLocator;
import org.apache.xml.dtm.DTMFilter;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.dtm.Axis;

import javax.xml.transform.ErrorListener;
import javax.xml.transform.TransformerException;

/**
 * <meta name="usage" content="advanced"/>
 * An instance of this class compiles an XPath string expression into 
 * a Expression object.  This class compiles the string into a sequence 
 * of operation codes (op map) and then builds from that into an Expression 
 * tree.
 */
public class Compiler extends OpMap
{

  /**
   * Construct a Compiler object with a specific ErrorListener and 
   * SourceLocator where the expression is located.
   *
   * @param errorHandler Error listener where messages will be sent, or null 
   *                     if messages should be sent to System err.
   * @param locator The location object where the expression lives, which 
   *                may be null, but which, if not null, must be valid over 
   *                the long haul, in other words, it will not be cloned.
   */
  public Compiler(ErrorListener errorHandler, SourceLocator locator)
  {
    m_errorHandler = errorHandler;
    m_locator = locator;
  }

  /**
   * Construct a Compiler instance that has a null error listener and a 
   * null source locator.
   */
  public Compiler()
  {
    m_errorHandler = null;
    m_locator = null;
  }

  /**
   * <meta name="usage" content="advanced"/>
   * Execute the XPath object from a given opcode position.
   * @param xctxt The execution context.
   * @param context The current source tree context node.
   * @param opPos The current position in the xpath.m_opMap array.
   * @param callback Interface that implements the processLocatedNode method.
   * @param callbackInfo Object that will be passed to the processLocatedNode method.
   * @return The result of the XPath.
   *
   * @throws TransformerException if there is a syntax or other error.
   */
  public Expression compile(int opPos) throws TransformerException
  {

    int op = getOp(opPos);

    Expression expr = null;
    // System.out.println(getPatternString()+"op: "+op);
    switch (op)
    {
    case OpCodes.OP_XPATH :
      expr = compile(opPos + 2); break;
    case OpCodes.OP_OR :
      expr = or(opPos); break;
    case OpCodes.OP_AND :
      expr = and(opPos); break;
    case OpCodes.OP_NOTEQUALS :
      expr = notequals(opPos); break;
    case OpCodes.OP_EQUALS :
      expr = equals(opPos); break;
    case OpCodes.OP_LTE :
      expr = lte(opPos); break;
    case OpCodes.OP_LT :
      expr = lt(opPos); break;
    case OpCodes.OP_GTE :
      expr = gte(opPos); break;
    case OpCodes.OP_GT :
      expr = gt(opPos); break;
    case OpCodes.OP_PLUS :
      expr = plus(opPos); break;
    case OpCodes.OP_MINUS :
      expr = minus(opPos); break;
    case OpCodes.OP_MULT :
      expr = mult(opPos); break;
    case OpCodes.OP_DIV :
      expr = div(opPos); break;
    case OpCodes.OP_MOD :
      expr = mod(opPos); break;
//    case OpCodes.OP_QUO :
//      expr = quo(opPos); break;
    case OpCodes.OP_NEG :
      expr = neg(opPos); break;
    case OpCodes.OP_STRING :
      expr = string(opPos); break;
    case OpCodes.OP_BOOL :
      expr = bool(opPos); break;
    case OpCodes.OP_NUMBER :
      expr = number(opPos); break;
    case OpCodes.OP_UNION :
      expr = union(opPos); break;
    case OpCodes.OP_LITERAL :
      expr = literal(opPos); break;
    case OpCodes.OP_VARIABLE :
      expr = variable(opPos); break;
    case OpCodes.OP_GROUP :
      expr = group(opPos); break;
    case OpCodes.OP_NUMBERLIT :
      expr = numberlit(opPos); break;
    case OpCodes.OP_ARGUMENT :
      expr = arg(opPos); break;
    case OpCodes.OP_EXTFUNCTION :
      expr = compileExtension(opPos); break;
    case OpCodes.OP_FUNCTION :
      expr = compileFunction(opPos); break;
    case OpCodes.OP_LOCATIONPATH :
      expr = locationPath(opPos); break;
    case OpCodes.OP_PREDICATE :
      expr = null; break;  // should never hit this here.
    case OpCodes.OP_MATCHPATTERN :
      expr = matchPattern(opPos + 2); break;
    case OpCodes.OP_LOCATIONPATHPATTERN :
      expr = locationPathPattern(opPos); break;
    case OpCodes.OP_QUO:
      error(XPATHErrorResources.ER_UNKNOWN_OPCODE,
            new Object[]{ "quo" });  //"ERROR! Unknown op code: "+m_opMap[opPos]);
      break;
    default :
      error(XPATHErrorResources.ER_UNKNOWN_OPCODE,
            new Object[]{ Integer.toString(getOp(opPos)) });  //"ERROR! Unknown op code: "+m_opMap[opPos]);
    }
//    if(null != expr)
//      expr.setSourceLocator(m_locator);

    return expr;
  }

  /**
   * Bottle-neck compilation of an operation with left and right operands.
   *
   * @param operation non-null reference to parent operation.
   * @param opPos The op map position of the parent operation.
   *
   * @return reference to {@link org.apache.xpath.operations.Operation} instance.
   *
   * @throws TransformerException if there is a syntax or other error.
   */
  private Expression compileOperation(Operation operation, int opPos)
          throws TransformerException
  {

    int leftPos = getFirstChildPos(opPos);
    int rightPos = getNextOpPos(leftPos);

    operation.setLeftRight(compile(leftPos), compile(rightPos));

    return operation;
  }

  /**
   * Bottle-neck compilation of a unary operation.
   *
   * @param unary The parent unary operation.
   * @param opPos The position in the op map of the parent operation.
   *
   * @return The unary argument.
   *
   * @throws TransformerException if syntax or other error occurs.
   */
  private Expression compileUnary(UnaryOperation unary, int opPos)
          throws TransformerException
  {

    int rightPos = getFirstChildPos(opPos);

    unary.setRight(compile(rightPos));

    return unary;
  }

  /**
   * Compile an 'or' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Or} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression or(int opPos) throws TransformerException
  {
    return compileOperation(new Or(), opPos);
  }

  /**
   * Compile an 'and' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.And} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression and(int opPos) throws TransformerException
  {
    return compileOperation(new And(), opPos);
  }

  /**
   * Compile a '!=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.NotEquals} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression notequals(int opPos) throws TransformerException
  {
    return compileOperation(new NotEquals(), opPos);
  }

  /**
   * Compile a '=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Equals} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression equals(int opPos) throws TransformerException
  {
    return compileOperation(new Equals(), opPos);
  }

  /**
   * Compile a '<=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Lte} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression lte(int opPos) throws TransformerException
  {
    return compileOperation(new Lte(), opPos);
  }

  /**
   * Compile a '<' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Lt} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression lt(int opPos) throws TransformerException
  {
    return compileOperation(new Lt(), opPos);
  }

  /**
   * Compile a '>=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Gte} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression gte(int opPos) throws TransformerException
  {
    return compileOperation(new Gte(), opPos);
  }

  /**
   * Compile a '>' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Gt} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression gt(int opPos) throws TransformerException
  {
    return compileOperation(new Gt(), opPos);
  }

  /**
   * Compile a '+' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Plus} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression plus(int opPos) throws TransformerException
  {
    return compileOperation(new Plus(), opPos);
  }

  /**
   * Compile a '-' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Minus} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression minus(int opPos) throws TransformerException
  {
    return compileOperation(new Minus(), opPos);
  }

  /**
   * Compile a '*' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Mult} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression mult(int opPos) throws TransformerException