eclipse.org-common/system/xml_sax_parsing.php

<?php
/**
 * *****************************************************************************
 * Copyright (c) 2006 Eclipse Foundation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Wayne Beaton (Eclipse Foundation)- initial API and implementation
 * *****************************************************************************
 */

// *****************************************************************************
//
// ** THIS FUNCTIONALITY IN THIS FILE IS DEPRECATED.
// ** USE THE XML_SIMPLE APIS INSTEAD.
//
// news.php
//
// Author: Wayne Beaton
// Date: 2005-11-07
//
// Description: This file contains code to assist with using a SAX parser
// on an XML file. Beware: it's weird.
//
// ****************************************************************************

/*
 * This function does the actual work of parsing the RSS
 * file into an object representation. We use a SAX parser
 * to do this.
 * Note that this function is intended to be used with relatively
 * short files (the entire file contents are loaded into memory).
 * If the RSS files start to get too large, this method will need
 * to be updated.
 * @deprecated
 */
function parse_xml_file($file_name, & $file_handler) {
  $file_handler->initialize();

  // Read the entire file contents in to memory.
  // If file sizes get too large, we'll have to be smarter here.
  $file = fopen($file_name, "r");
  $xml = fread($file, filesize($file_name));
  fclose($file);

  parse_xml_string($xml, $file_handler);
}

function parse_xml_string($xml, & $file_handler) {
  $GLOBALS['handler'] = $file_handler;
  $parser = xml_parser_create();
  xml_set_element_handler($parser, 'sax_start_handler', 'sax_end_handler');
  xml_set_character_data_handler($parser, 'sax_data_handler');
  xml_parse($parser, $xml);
  if (xml_get_error_code($parser))
    throw new SaxParsingException(xml_error_string($parser));
}

class SaxParsingException extends Exception {

  public function __construct($message, $code = 0) {
    parent::__construct($message, $code);
  }

}

/*
 * The $handler variable is global. It manages all the call backs
 * that come (indirectly) from the SAX parser.
 */
$handler = null;

/*
 * SAX parser callback method to handle the start of an element.
 * This method just defers to the global handler to do the actual
 * work.
 */
function sax_start_handler($parser, $name, $attributes) {
  global $handler;
  $handler->start($name, $attributes);
}

/*
 * SAX parser callback method to handle the text for an element.
 * This method just defers to the global handler to do the actual
 * work.
 */
function sax_data_handler($parser, $data) {
  global $handler;
  $handler->data($data);
}

/*
 * SAX parser callback method to handle the end of an element.
 * This method just defers to the global handler to do the actual
 * work.
 */
function sax_end_handler($parser, $name) {
  global $handler;
  $handler->end($name);
}

/*
 * The XmlHandler class is the focal point of the SAX parser callbacks.
 * It keeps track of a stack of element handlers. The element handlers
 * are used to handle whatever elements come in.
 */
class XmlFileHandler {
  var $stack;

  function XmlFileHandler() {
    $this->stack = array();
  }

  function initialize() {
    $element_handler = $this->get_root_element_handler();
    array_push($this->stack, $element_handler);
  }

  function get_root_element_handler() {
    return new DoNothingHandler();
  }

  function end_root_element_handler($handler) {
  }

  /*
   * Handle the start callback. Here, we get the current element handler
   * from the top of the stack and ask it what to do. The element handler
   * is asked to provide a new handler to handle the new element. That new
   * handler is put on the top of the stack and will handle all future
   * callbacks until it is removed (by the end method).
   */
  function start($name, $attributes) {
    $handler = & array_last($this->stack);
    $next = & $handler->get_next($name, $attributes);
    array_push($this->stack, $next);
  }

  /*
   * Data has been encountered, send the data to the current element handler
   * to sort out what needs to be done.
   */
  function data($data) {
    $handler = & array_last($this->stack);
    $handler->data($data);
  }

  /*
   * The end of an element has occurred. Pop the current element handler
   * from the top of the stack and tell it that it's work is done.
   */
  function end($name) {
    $handler = & array_pop($this->stack);
    $handler->end($name);

    $next_handler = & array_last($this->stack);
    $next_handler->end_handler($name, $handler);

    // If we've just popped off the last actual element handler, leaving
    // only the root handler at the top of the stack, send it the end message.
    if (count($this->stack) == 1)
      $this->end_root_element_handler($handler);
  }

}

class XmlElementHandler {

  function &get_next($name, $attributes) {
    $method_name = "get_" . str_replace("-", "_", $name) . "_handler";
    if (method_exists($this, $method_name)) {
      return $this->$method_name($attributes);
    }
    else {
      return new DoNothingHandler();
    }
  }

  function end_handler($name, $handler) {
    $method_name = "end_" . str_replace("-", "_", $name) . "_handler";
    if (method_exists($this, $method_name)) {
      return $this->$method_name($handler);
    }
  }

  function initialize() {
  }

  /*
   * Ignore data for this element.
   */
  function data($data) {
  }

  function start($name) {
  }

  /*
   * Ignore data for this element.
   */
  function end($name) {
  }

}

class SimpleTextHandler extends XmlElementHandler {
  var $text;

  function &get_next($name, $attributes) {
    return new DoNothingHandler();
  }

  function data($data) {
    $this->text .= $data;
  }

  function end($name) {
    $this->text = html_entity_decode($this->text);
  }

}

class SimplePropertyHandler extends SimpleTextHandler {
  var $owner;
  var $property;

  function SimplePropertyHandler(& $owner, $property) {
    $this->owner = & $owner;
    $this->property = $property;
  }

  function end($name) {
    parent::end($name);
    $this->set_property_value($this->text);
  }

  function set_property_value(& $value) {
    $property = $this->property;
    $this->owner->$property = $value;
  }

}

class DoNothingHandler extends XmlElementHandler {

  function &get_next($name, $attributes) {
    return $this;
  }

}

function &array_last(& $array) {
  return $array[count($array) - 1];
}