<?php
/**
 * PHPUnit
 *
 * Copyright (c) 2002-2011, Sebastian Bergmann <sebastian@phpunit.de>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * * 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.
 *
 * * Neither the name of Sebastian Bergmann nor the names of his
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND 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.
 *
 * @package    PHPUnit
 * @subpackage Util
 * @author     Sebastian Bergmann <sebastian@phpunit.de>
 * @copyright  2002-2011 Sebastian Bergmann <sebastian@phpunit.de>
 * @license    http://www.opensource.org/licenses/bsd-license.php  BSD License
 * @link       http://www.phpunit.de/
 * @since      File available since Release 3.2.0
 */

/**
 * XML helpers.
 *
 * @package    PHPUnit
 * @subpackage Util
 * @author     Sebastian Bergmann <sebastian@phpunit.de>
 * @copyright  2002-2011 Sebastian Bergmann <sebastian@phpunit.de>
 * @license    http://www.opensource.org/licenses/bsd-license.php  BSD License
 * @version    Release: 3.5.9
 * @link       http://www.phpunit.de/
 * @since      Class available since Release 3.2.0
 */
class PHPUnit_Util_XML
{

    /**
     * @param  string $string
     * @return string
     * @author Kore Nordmann <mail@kore-nordmann.de>
     * @since  Method available since Release 3.4.6
     */
    public static function prepareString($string)
    {
        return preg_replace('([\\x00-\\x04\\x0b\\x0c\\x0e-\\x1f\\x7f])e', 'sprintf( "&#x%02x;", ord( "\\1" ) )', htmlspecialchars(self :: convertToUtf8($string), ENT_COMPAT, 'UTF-8'));
    }

    /**
     * Converts a string to UTF-8 encoding.
     *
     * @param  string $string
     * @return string
     * @since  Method available since Release 3.2.19
     */
    protected static function convertToUtf8($string)
    {
        if (! self :: isUtf8($string))
        {
            if (function_exists('mb_convert_encoding'))
            {
                $string = mb_convert_encoding($string, 'UTF-8');
            }
            else
            {
                $string = utf8_encode($string);
            }
        }
        
        return $string;
    }

    /**
     * Checks a string for UTF-8 encoding.
     *
     * @param  string $string
     * @return boolean
     * @since  Method available since Release 3.3.0
     */
    protected static function isUtf8($string)
    {
        $length = strlen($string);
        
        for($i = 0; $i < $length; $i ++)
        {
            if (ord($string[$i]) < 0x80)
            {
                $n = 0;
            }
            
            else 
                if ((ord($string[$i]) & 0xE0) == 0xC0)
                {
                    $n = 1;
                }
                
                else 
                    if ((ord($string[$i]) & 0xF0) == 0xE0)
                    {
                        $n = 2;
                    }
                    
                    else 
                        if ((ord($string[$i]) & 0xF0) == 0xF0)
                        {
                            $n = 3;
                        }
                        
                        else
                        {
                            return FALSE;
                        }
            
            for($j = 0; $j < $n; $j ++)
            {
                if ((++ $i == $length) || ((ord($string[$i]) & 0xC0) != 0x80))
                {
                    return FALSE;
                }
            }
        }
        
        return TRUE;
    }

    /**
     * Loads an XML (or HTML) file into a DOMDocument object.
     *
     * @param  string  $filename
     * @param  boolean $isHtml
     * @return DOMDocument
     * @since  Method available since Release 3.3.0
     */
    public static function loadFile($filename, $isHtml = FALSE)
    {
        $reporting = error_reporting(0);
        $contents = file_get_contents($filename);
        error_reporting($reporting);
        
        if ($contents === FALSE)
        {
            throw new PHPUnit_Framework_Exception(sprintf('Could not read "%s".', $filename));
        }
        
        return self :: load($contents, $isHtml, $filename);
    }

    /**
     * Load an $actual document into a DOMDocument.  This is called
     * from the selector assertions.
     *
     * If $actual is already a DOMDocument, it is returned with
     * no changes.  Otherwise, $actual is loaded into a new DOMDocument
     * as either HTML or XML, depending on the value of $isHtml.
     *
     * Note: prior to PHPUnit 3.3.0, this method loaded a file and
     * not a string as it currently does.  To load a file into a
     * DOMDocument, use loadFile() instead.
     *
     * @param  string|DOMDocument  $actual
     * @param  boolean             $isHtml
     * @param  string              $filename
     * @return DOMDocument
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     */
    public static function load($actual, $isHtml = FALSE, $filename = '')
    {
        if ($actual instanceof DOMDocument)
        {
            return $actual;
        }
        
        $internal = libxml_use_internal_errors(TRUE);
        $reporting = error_reporting(0);
        $dom = new DOMDocument();
        
        if ($isHtml)
        {
            $loaded = $dom->loadHTML($actual);
        }
        else
        {
            $loaded = $dom->loadXML($actual);
        }
        
        libxml_use_internal_errors($internal);
        error_reporting($reporting);
        
        if ($loaded === FALSE)
        {
            $message = '';
            
            foreach (libxml_get_errors() as $error)
            {
                $message .= $error->message;
            }
            
            if ($filename != '')
            {
                throw new PHPUnit_Framework_Exception(sprintf('Could not load "%s".%s', 

                $filename, $message != '' ? "\n" . $message : ''));
            }
            else
            {
                throw new PHPUnit_Framework_Exception($message);
            }
        }
        
        return $dom;
    }

    /**
     *
     *
     * @param  DOMNode $node
     * @return string
     * @since  Method available since Release 3.4.0
     */
    public static function nodeToText(DOMNode $node)
    {
        if ($node->childNodes->length == 1)
        {
            return $node->nodeValue;
        }
        
        $result = '';
        
        foreach ($node->childNodes as $childNode)
        {
            $result .= $node->ownerDocument->saveXML($childNode);
        }
        
        return $result;
    }

    /**
     *
     *
     * @param  DOMNode $node
     * @since  Method available since Release 3.3.0
     * @author Mattis Stordalen Flister <mattis@xait.no>
     */
    public static function removeCharacterDataNodes(DOMNode $node)
    {
        if ($node->hasChildNodes())
        {
            for($i = $node->childNodes->length - 1; $i >= 0; $i --)
            {
                if (($child = $node->childNodes->item($i)) instanceof DOMCharacterData)
                {
                    $node->removeChild($child);
                }
            }
        }
    }

    /**
     * "Convert" a DOMElement object into a PHP variable.
     *
     * @param  DOMElement $element
     * @return mixed
     * @since  Method available since Release 3.4.0
     */
    public static function xmlToVariable(DOMElement $element)
    {
        $variable = NULL;
        
        switch ($element->tagName)
        {
            case 'array' :
                {
                    $variable = array();
                    
                    foreach ($element->getElementsByTagName('element') as $element)
                    {
                        $value = self :: xmlToVariable($element->childNodes->item(1));
                        
                        if ($element->hasAttribute('key'))
                        {
                            $variable[(string) $element->getAttribute('key')] = $value;
                        }
                        else
                        {
                            $variable[] = $value;
                        }
                    }
                }
                break;
            
            case 'object' :
                {
                    $className = $element->getAttribute('class');
                    
                    if ($element->hasChildNodes())
                    {
                        $arguments = $element->childNodes->item(1)->childNodes;
                        $constructorArgs = array();
                        
                        foreach ($arguments as $argument)
                        {
                            if ($argument instanceof DOMElement)
                            {
                                $constructorArgs[] = self :: xmlToVariable($argument);
                            }
                        }
                        
                        $class = new ReflectionClass($className);
                        $variable = $class->newInstanceArgs($constructorArgs);
                    }
                    else
                    {
                        $variable = new $className();
                    }
                }
                break;
            
            case 'boolean' :
                {
                    $variable = $element->nodeValue == 'true' ? TRUE : FALSE;
                }
                break;
            
            case 'integer' :
            case 'double' :
            case 'string' :
                {
                    $variable = $element->nodeValue;
                    
                    settype($variable, $element->tagName);
                }
                break;
        }
        
        return $variable;
    }

    /**
     * Validate list of keys in the associative array.
     *
     * @param  array $hash
     * @param  array $validKeys
     * @return array
     * @throws InvalidArgumentException
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     */
    public static function assertValidKeys(array $hash, array $validKeys)
    {
        $valids = array();
        
        // Normalize validation keys so that we can use both indexed and
        // associative arrays.
        foreach ($validKeys as $key => $val)
        {
            is_int($key) ? $valids[$val] = NULL : $valids[$key] = $val;
        }
        
        $validKeys = array_keys($valids);
        
        // Check for invalid keys.
        foreach ($hash as $key => $value)
        {
            if (! in_array($key, $validKeys))
            {
                $unknown[] = $key;
            }
        }
        
        if (! empty($unknown))
        {
            throw new InvalidArgumentException('Unknown key(s): ' . implode(', ', $unknown));
        }
        
        // Add default values for any valid keys that are empty.
        foreach ($valids as $key => $value)
        {
            if (! isset($hash[$key]))
            {
                $hash[$key] = $value;
            }
        }
        
        return $hash;
    }

    /**
     * Parse a CSS selector into an associative array suitable for
     * use with findNodes().
     *
     * @param  string $selector
     * @param  mixed  $content
     * @return array
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     */
    public static function convertSelectToTag($selector, $content = TRUE)
    {
        $selector = trim(preg_replace("/\s+/", " ", $selector));
        
        // substitute spaces within attribute value
        while (preg_match('/\[[^\]]+"[^"]+\s[^"]+"\]/', $selector))
        {
            $selector = preg_replace('/(\[[^\]]+"[^"]+)\s([^"]+"\])/', "$1__SPACE__$2", $selector);
        }
        
        if (strstr($selector, ' '))
        {
            $elements = explode(' ', $selector);
        }
        else
        {
            $elements = array($selector);
        }
        
        $previousTag = array();
        
        foreach (array_reverse($elements) as $element)
        {
            $element = str_replace('__SPACE__', ' ', $element);
            
            // child selector
            if ($element == '>')
            {
                $previousTag = array('child' => $previousTag['descendant']);
                continue;
            }
            
            $tag = array();
            
            // match element tag
            preg_match("/^([^\.#\[]*)/", $element, $eltMatches);
            
            if (! empty($eltMatches[1]))
            {
                $tag['tag'] = $eltMatches[1];
            }
            
            // match attributes (\[[^\]]*\]*), ids (#[^\.#\[]*),
            // and classes (\.[^\.#\[]*))
            preg_match_all("/(\[[^\]]*\]*|#[^\.#\[]*|\.[^\.#\[]*)/", $element, $matches);
            
            if (! empty($matches[1]))
            {
                $classes = array();
                $attrs = array();
                
                foreach ($matches[1] as $match)
                {
                    // id matched
                    if (substr($match, 0, 1) == '#')
                    {
                        $tag['id'] = substr($match, 1);
                    }
                    
                    // class matched
                    else 
                        if (substr($match, 0, 1) == '.')
                        {
                            $classes[] = substr($match, 1);
                        }
                        
                        // attribute matched
                        else 
                            if (substr($match, 0, 1) == '[' && substr($match, - 1, 1) == ']')
                            {
                                $attribute = substr($match, 1, strlen($match) - 2);
                                $attribute = str_replace('"', '', $attribute);
                                
                                // match single word
                                if (strstr($attribute, '~='))
                                {
                                    list($key, $value) = explode('~=', $attribute);
                                    $value = "regexp:/.*\b$value\b.*/";
                                }
                                
                                // match substring
                                else 
                                    if (strstr($attribute, '*='))
                                    {
                                        list($key, $value) = explode('*=', $attribute);
                                        $value = "regexp:/.*$value.*/";
                                    }
                                    
                                    // exact match
                                    else
                                    {
                                        list($key, $value) = explode('=', $attribute);
                                    }
                                
                                $attrs[$key] = $value;
                            }
                }
                
                if ($classes)
                {
                    $tag['class'] = join(' ', $classes);
                }
                
                if ($attrs)
                {
                    $tag['attributes'] = $attrs;
                }
            }
            
            // tag content
            if (is_string($content))
            {
                $tag['content'] = $content;
            }
            
            // determine previous child/descendants
            if (! empty($previousTag['descendant']))
            {
                $tag['descendant'] = $previousTag['descendant'];
            }
            
            else 
                if (! empty($previousTag['child']))
                {
                    $tag['child'] = $previousTag['child'];
                }
            
            $previousTag = array('descendant' => $tag);
        }
        
        return $tag;
    }

    /**
     * Parse an $actual document and return an array of DOMNodes
     * matching the CSS $selector.  If an error occurs, it will
     * return FALSE.
     *
     * To only return nodes containing a certain content, give
     * the $content to match as a string.  Otherwise, setting
     * $content to TRUE will return all nodes matching $selector.
     *
     * The $actual document may be a DOMDocument or a string
     * containing XML or HTML, identified by $isHtml.
     *
     * @param  array   $selector
     * @param  string  $content
     * @param  mixed   $actual
     * @param  boolean $isHtml
     * @return false|array
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     * @author Tobias Schlitt <toby@php.net>
     */
    public static function cssSelect($selector, $content, $actual, $isHtml = TRUE)
    {
        $matcher = self :: convertSelectToTag($selector, $content);
        $dom = self :: load($actual, $isHtml);
        $tags = self :: findNodes($dom, $matcher, $isHtml);
        
        return $tags;
    }

    /**
     * Parse out the options from the tag using DOM object tree.
     *
     * @param  DOMDocument $dom
     * @param  array       $options
     * @param  boolean     $isHtml
     * @return array
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     * @author Tobias Schlitt <toby@php.net>
     */
    public static function findNodes(DOMDocument $dom, array $options, $isHtml = TRUE)
    {
        $valid = array('id', 'class', 'tag', 'content', 'attributes', 'parent', 'child', 'ancestor', 'descendant', 
                'children');
        
        $filtered = array();
        $options = self :: assertValidKeys($options, $valid);
        
        // find the element by id
        if ($options['id'])
        {
            $options['attributes']['id'] = $options['id'];
        }
        
        if ($options['class'])
        {
            $options['attributes']['class'] = $options['class'];
        }
        
        // find the element by a tag type
        if ($options['tag'])
        {
            if ($isHtml)
            {
                $elements = self :: getElementsByCaseInsensitiveTagName($dom, $options['tag']);
            }
            else
            {
                $elements = $dom->getElementsByTagName($options['tag']);
            }
            
            foreach ($elements as $element)
            {
                $nodes[] = $element;
            }
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // no tag selected, get them all
        else
        {
            $tags = array('a', 'abbr', 'acronym', 'address', 'area', 'b', 'base', 'bdo', 'big', 'blockquote', 'body', 
                    'br', 'button', 'caption', 'cite', 'code', 'col', 'colgroup', 'dd', 'del', 'div', 'dfn', 'dl', 'dt', 
                    'em', 'fieldset', 'form', 'frame', 'frameset', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'head', 'hr', 
                    'html', 'i', 'iframe', 'img', 'input', 'ins', 'kbd', 'label', 'legend', 'li', 'link', 'map', 'meta', 
                    'noframes', 'noscript', 'object', 'ol', 'optgroup', 'option', 'p', 'param', 'pre', 'q', 'samp', 
                    'script', 'select', 'small', 'span', 'strong', 'style', 'sub', 'sup', 'table', 'tbody', 'td', 
                    'textarea', 'tfoot', 'th', 'thead', 'title', 'tr', 'tt', 'ul', 'var');
            
            foreach ($tags as $tag)
            {
                if ($isHtml)
                {
                    $elements = self :: getElementsByCaseInsensitiveTagName($dom, $tag);
                }
                else
                {
                    $elements = $dom->getElementsByTagName($tag);
                }
                
                foreach ($elements as $element)
                {
                    $nodes[] = $element;
                }
            }
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by attributes
        if ($options['attributes'])
        {
            foreach ($nodes as $node)
            {
                $invalid = FALSE;
                
                foreach ($options['attributes'] as $name => $value)
                {
                    // match by regexp if like "regexp:/foo/i"
                    if (preg_match('/^regexp\s*:\s*(.*)/i', $value, $matches))
                    {
                        if (! preg_match($matches[1], $node->getAttribute($name)))
                        {
                            $invalid = TRUE;
                        }
                    }
                    
                    // class can match only a part
                    else 
                        if ($name == 'class')
                        {
                            // split to individual classes
                            $findClasses = explode(' ', preg_replace("/\s+/", " ", $value));
                            
                            $allClasses = explode(' ', preg_replace("/\s+/", " ", $node->getAttribute($name)));
                            
                            // make sure each class given is in the actual node
                            foreach ($findClasses as $findClass)
                            {
                                if (! in_array($findClass, $allClasses))
                                {
                                    $invalid = TRUE;
                                }
                            }
                        }
                        
                        // match by exact string
                        else
                        {
                            if ($node->getAttribute($name) != $value)
                            {
                                $invalid = TRUE;
                            }
                        }
                }
                
                // if every attribute given matched
                if (! $invalid)
                {
                    $filtered[] = $node;
                }
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by content
        if ($options['content'] !== NULL)
        {
            foreach ($nodes as $node)
            {
                $invalid = FALSE;
                
                // match by regexp if like "regexp:/foo/i"
                if (preg_match('/^regexp\s*:\s*(.*)/i', $options['content'], $matches))
                {
                    if (! preg_match($matches[1], self :: getNodeText($node)))
                    {
                        $invalid = TRUE;
                    }
                }
                
                // match by exact string
                else 
                    if (strstr(self :: getNodeText($node), $options['content']) === FALSE)
                    {
                        $invalid = TRUE;
                    }
                
                if (! $invalid)
                {
                    $filtered[] = $node;
                }
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by parent node
        if ($options['parent'])
        {
            $parentNodes = self :: findNodes($dom, $options['parent'], $isHtml);
            $parentNode = isset($parentNodes[0]) ? $parentNodes[0] : NULL;
            
            foreach ($nodes as $node)
            {
                if ($parentNode !== $node->parentNode)
                {
                    break;
                }
                
                $filtered[] = $node;
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by child node
        if ($options['child'])
        {
            $childNodes = self :: findNodes($dom, $options['child'], $isHtml);
            $childNodes = ! empty($childNodes) ? $childNodes : array();
            
            foreach ($nodes as $node)
            {
                foreach ($node->childNodes as $child)
                {
                    foreach ($childNodes as $childNode)
                    {
                        if ($childNode === $child)
                        {
                            $filtered[] = $node;
                        }
                    }
                }
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by ancestor
        if ($options['ancestor'])
        {
            $ancestorNodes = self :: findNodes($dom, $options['ancestor'], $isHtml);
            $ancestorNode = isset($ancestorNodes[0]) ? $ancestorNodes[0] : NULL;
            
            foreach ($nodes as $node)
            {
                $parent = $node->parentNode;
                
                while ($parent->nodeType != XML_HTML_DOCUMENT_NODE)
                {
                    if ($parent === $ancestorNode)
                    {
                        $filtered[] = $node;
                    }
                    
                    $parent = $parent->parentNode;
                }
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by descendant
        if ($options['descendant'])
        {
            $descendantNodes = self :: findNodes($dom, $options['descendant'], $isHtml);
            $descendantNodes = ! empty($descendantNodes) ? $descendantNodes : array();
            
            foreach ($nodes as $node)
            {
                foreach (self :: getDescendants($node) as $descendant)
                {
                    foreach ($descendantNodes as $descendantNode)
                    {
                        if ($descendantNode === $descendant)
                        {
                            $filtered[] = $node;
                        }
                    }
                }
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return FALSE;
            }
        }
        
        // filter by children
        if ($options['children'])
        {
            $validChild = array('count', 'greater_than', 'less_than', 'only');
            $childOptions = self :: assertValidKeys($options['children'], $validChild);
            
            foreach ($nodes as $node)
            {
                $childNodes = $node->childNodes;
                
                foreach ($childNodes as $childNode)
                {
                    if ($childNode->nodeType !== XML_CDATA_SECTION_NODE && $childNode->nodeType !== XML_TEXT_NODE)
                    {
                        $children[] = $childNode;
                    }
                }
                
                // we must have children to pass this filter
                if (! empty($children))
                {
                    // exact count of children
                    if ($childOptions['count'] !== NULL)
                    {
                        if (count($children) !== $childOptions['count'])
                        {
                            break;
                        }
                    }
                    
                    // range count of children
                    else 
                        if ($childOptions['less_than'] !== NULL && $childOptions['greater_than'] !== NULL)
                        {
                            if (count($children) >= $childOptions['less_than'] || count($children) <= $childOptions['greater_than'])
                            {
                                break;
                            }
                        }
                        
                        // less than a given count
                        else 
                            if ($childOptions['less_than'] !== NULL)
                            {
                                if (count($children) >= $childOptions['less_than'])
                                {
                                    break;
                                }
                            }
                            
                            // more than a given count
                            else 
                                if ($childOptions['greater_than'] !== NULL)
                                {
                                    if (count($children) <= $childOptions['greater_than'])
                                    {
                                        break;
                                    }
                                }
                    
                    // match each child against a specific tag
                    if ($childOptions['only'])
                    {
                        $onlyNodes = self :: findNodes($dom, $childOptions['only'], $isHtml);
                        
                        // try to match each child to one of the 'only' nodes
                        foreach ($children as $child)
                        {
                            $matched = FALSE;
                            
                            foreach ($onlyNodes as $onlyNode)
                            {
                                if ($onlyNode === $child)
                                {
                                    $matched = TRUE;
                                }
                            }
                            
                            if (! $matched)
                            {
                                break (2);
                            }
                        }
                    }
                    
                    $filtered[] = $node;
                }
            }
            
            $nodes = $filtered;
            $filtered = array();
            
            if (empty($nodes))
            {
                return;
            }
        }
        
        // return the first node that matches all criteria
        return ! empty($nodes) ? $nodes : array();
    }

    /**
     * Recursively get flat array of all descendants of this node.
     *
     * @param  DOMNode $node
     * @return array
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     */
    protected static function getDescendants(DOMNode $node)
    {
        $allChildren = array();
        $childNodes = $node->childNodes ? $node->childNodes : array();
        
        foreach ($childNodes as $child)
        {
            if ($child->nodeType === XML_CDATA_SECTION_NODE || $child->nodeType === XML_TEXT_NODE)
            {
                continue;
            }
            
            $children = self :: getDescendants($child);
            $allChildren = array_merge($allChildren, $children, array($child));
        }
        
        return isset($allChildren) ? $allChildren : array();
    }

    /**
     * Gets elements by case insensitive tagname.
     *
     * @param  DOMDocument $dom
     * @param  string      $tag
     * @return DOMNodeList
     * @since  Method available since Release 3.4.0
     */
    protected static function getElementsByCaseInsensitiveTagName(DOMDocument $dom, $tag)
    {
        $elements = $dom->getElementsByTagName(strtolower($tag));
        
        if ($elements->length == 0)
        {
            $elements = $dom->getElementsByTagName(strtoupper($tag));
        }
        
        return $elements;
    }

    /**
     * Get the text value of this node's child text node.
     *
     * @param  DOMNode $node
     * @return string
     * @since  Method available since Release 3.3.0
     * @author Mike Naberezny <mike@maintainable.com>
     * @author Derek DeVries <derek@maintainable.com>
     */
    protected static function getNodeText(DOMNode $node)
    {
        if (! $node->childNodes instanceof DOMNodeList)
        {
            return '';
        }
        
        $result = '';
        
        foreach ($node->childNodes as $childNode)
        {
            if ($childNode->nodeType === XML_TEXT_NODE)
            {
                $result .= trim($childNode->data) . ' ';
            }
            else
            {
                $result .= self :: getNodeText($childNode);
            }
        }
        
        return str_replace('  ', ' ', $result);
    }
}