symfony/src/Symfony/Components/CssSelector/XPathExpr.php

<?php

namespace Symfony\Components\CssSelector;

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien.potencier@symfony-project.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * XPathExpr represents an XPath expression.
 *
 * This component is a port of the Python lxml library,
 * which is copyright Infrae and distributed under the BSD license.
 *
 * @package    Symfony
 * @subpackage Components_CssSelector
 * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
 */
class XPathExpr
{
  protected $prefix;
  protected $path;
  protected $element;
  protected $condition;
  protected $starPrefix;

  public function __construct($prefix = null, $path = null, $element = '*', $condition = null, $starPrefix = false)
  {
    $this->prefix = $prefix;
    $this->path = $path;
    $this->element = $element;
    $this->condition = $condition;
    $this->starPrefix = $starPrefix;
  }

  public function getPrefix()
  {
    return $this->prefix;
  }

  public function getPath()
  {
    return $this->path;
  }

  public function hasStarPrefix()
  {
    return $this->starPrefix;
  }

  public function getElement()
  {
    return $this->element;
  }

  public function getCondition()
  {
    return $this->condition;
  }

  public function __toString()
  {
    $path = '';
    if (null !== $this->prefix)
    {
      $path .= $this->prefix;
    }

    if (null !== $this->path)
    {
      $path .= $this->path;
    }

    $path .= $this->element;

    if ($this->condition)
    {
      $path .= sprintf('[%s]', $this->condition);
    }

    return $path;
  }

  public function addCondition($condition)
  {
    if ($this->condition)
    {
      $this->condition = sprintf('%s and (%s)', $this->condition, $condition);
    }
    else
    {
      $this->condition = $condition;
    }
  }

  public function addPrefix($prefix)
  {
    if ($this->prefix)
    {
      $this->prefix = $prefix.$this->prefix;
    }
    else
    {
      $this->prefix = $prefix;
    }
  }

  public function addNameTest()
  {
    if ($this->element == '*')
    {
      // We weren't doing a test anyway
      return;
    }

    $this->addCondition(sprintf('name() = %s', XPathExpr::xpathLiteral($this->element)));
    $this->element = '*';
  }

  public function addStarPrefix()
  {
    /*
    Adds a /* prefix if there is no prefix.  This is when you need
    to keep context's constrained to a single parent.
    */
    if ($this->path)
    {
      $this->path .= '*/';
    }
    else
    {
      $this->path = '*/';
    }

    $this->starPrefix = true;
  }

  public function join($combiner, $other)
  {
    $prefix = (string) $this;

    $prefix .= $combiner;
    $path = $other->getPrefix().$other->getPath();

    /* We don't need a star prefix if we are joining to this other
       prefix; so we'll get rid of it */
    if ($other->hasStarPrefix() && $path == '*/')
    {
      $path = '';
    }
    $this->prefix = $prefix;
    $this->path = $path;
    $this->element = $other->getElement();
    $this->condition = $other->GetCondition();
  }

  static public function xpathLiteral($s)
  {
    if ($s instanceof Node\ElementNode)
    {
      // This is probably a symbol that looks like an expression...
      $s = $s->formatElement();
    }
    else
    {
      $s = (string) $s;
    }

    if (false === strpos($s, "'"))
    {
      return sprintf("'%s'", $s);
    }

    if (false === strpos($s, '"'))
    {
      return sprintf('"%s"', $s);
    }

    $string = $s;
    $parts = array();
    while (true)
    {
      if (false !== $pos = strpos($string, "'"))
      {
        $parts[] = sprintf("'%s'", substr($string, 0, $pos));
        $parts[] = "\"'\"";
        $string = substr($string, $pos + 1);
      }
      else
      {
        $parts[] = "'$string'";
        break;
      }
    }

    return sprintf('concat(%s)', implode($parts, ', '));
  }
}