Seditio Source
Root |
./othercms/xenForo 2.2.8/src/vendor/pelago/emogrifier/src/Emogrifier.php
<?php

namespace Pelago;

use
Pelago\Emogrifier\Utilities\CssConcatenator;

/**
 * This class provides functions for converting CSS styles into inline style attributes in your HTML code.
 *
 * For more information, please see the README.md file.
 *
 * @deprecated Will be removed for version 4.0.0. Please use the CssInliner class instead.
 *
 * @author Cameron Brooks
 * @author Jaime Prado
 * @author Oliver Klee <github@oliverklee.de>
 * @author Roman Ožana <ozana@omdesign.cz>
 * @author Sander Kruger <s.kruger@invessel.com>
 * @author Zoli Szabó <zoli.szabo+github@gmail.com>
 */
class Emogrifier
{
   
/**
     * @var int
     */
   
const CACHE_KEY_CSS = 0;

   
/**
     * @var int
     */
   
const CACHE_KEY_SELECTOR = 1;

   
/**
     * @var int
     */
   
const CACHE_KEY_XPATH = 2;

   
/**
     * @var int
     */
   
const CACHE_KEY_CSS_DECLARATIONS_BLOCK = 3;

   
/**
     * @var int
     */
   
const CACHE_KEY_COMBINED_STYLES = 4;

   
/**
     * for calculating nth-of-type and nth-child selectors
     *
     * @var int
     */
   
const INDEX = 0;

   
/**
     * for calculating nth-of-type and nth-child selectors
     *
     * @var int
     */
   
const MULTIPLIER = 1;

   
/**
     * @var string
     */
   
const ID_ATTRIBUTE_MATCHER = '/(\\w+)?\\#([\\w\\-]+)/';

   
/**
     * @var string
     */
   
const CLASS_ATTRIBUTE_MATCHER = '/(\\w+|[\\*\\]])?((\\.[\\w\\-]+)+)/';

   
/**
     * Regular expression component matching a static pseudo class in a selector, without the preceding ":",
     * for which the applicable elements can be determined (by converting the selector to an XPath expression).
     * (Contains alternation without a group and is intended to be placed within a capturing, non-capturing or lookahead
     * group, as appropriate for the usage context.)
     *
     * @var string
     */
   
const PSEUDO_CLASS_MATCHER = '(?:first|last|nth)-child|nth-of-type|not\\([[:ascii:]]*\\)';

   
/**
     * @var string
     */
   
const CONTENT_TYPE_META_TAG = '<meta http-equiv="Content-Type" content="text/html; charset=utf-8">';

   
/**
     * @var string
     */
   
const DEFAULT_DOCUMENT_TYPE = '<!DOCTYPE html>';

   
/**
     * @var string Regular expression part to match tag names that PHP's DOMDocument implementation is not aware are
     *      self-closing. These are mostly HTML5 elements, but for completeness <command> (obsolete) and <keygen>
     *      (deprecated) are also included.
     *
     * @see https://bugs.php.net/bug.php?id=73175
     */
   
const PHP_UNRECOGNIZED_VOID_TAGNAME_MATCHER = '(?:command|embed|keygen|source|track|wbr)';

   
/**
     * @var \DOMDocument
     */
   
protected $domDocument = null;

   
/**
     * @var \DOMXPath
     */
   
protected $xPath = null;

   
/**
     * @var string
     */
   
private $css = '';

   
/**
     * @var bool[]
     */
   
private $excludedSelectors = [];

   
/**
     * @var string[]
     */
   
private $unprocessableHtmlTags = ['wbr'];

   
/**
     * @var bool[]
     */
   
private $allowedMediaTypes = ['all' => true, 'screen' => true, 'print' => true];

   
/**
     * @var mixed[]
     */
   
private $caches = [
       
self::CACHE_KEY_CSS => [],
       
self::CACHE_KEY_SELECTOR => [],
       
self::CACHE_KEY_XPATH => [],
       
self::CACHE_KEY_CSS_DECLARATIONS_BLOCK => [],
       
self::CACHE_KEY_COMBINED_STYLES => [],
    ];

   
/**
     * the visited nodes with the XPath paths as array keys
     *
     * @var \DOMElement[]
     */
   
private $visitedNodes = [];

   
/**
     * the styles to apply to the nodes with the XPath paths as array keys for the outer array
     * and the attribute names/values as key/value pairs for the inner array
     *
     * @var string[][]
     */
   
private $styleAttributesForNodes = [];

   
/**
     * Determines whether the "style" attributes of tags in the the HTML passed to this class should be preserved.
     * If set to false, the value of the style attributes will be discarded.
     *
     * @var bool
     */
   
private $isInlineStyleAttributesParsingEnabled = true;

   
/**
     * Determines whether the <style> blocks in the HTML passed to this class should be parsed.
     *
     * If set to true, the <style> blocks will be removed from the HTML and their contents will be applied to the HTML
     * via inline styles.
     *
     * If set to false, the <style> blocks will be left as they are in the HTML.
     *
     * @var bool
     */
   
private $isStyleBlocksParsingEnabled = true;

   
/**
     * For calculating selector precedence order.
     * Keys are a regular expression part to match before a CSS name.
     * Values are a multiplier factor per match to weight specificity.
     *
     * @var int[]
     */
   
private $selectorPrecedenceMatchers = [
       
// IDs: worth 10000
       
'\\#' => 10000,
       
// classes, attributes, pseudo-classes (not pseudo-elements) except `:not`: worth 100
       
'(?:\\.|\\[|(?<!:):(?!not\\())' => 100,
       
// elements (not attribute values or `:not`), pseudo-elements: worth 1
       
'(?:(?<![="\':\\w\\-])|::)' => 1,
    ];

   
/**
     * @var string[]
     */
   
private $xPathRules = [
       
// attribute presence
       
'/^\\[(\\w+|\\w+\\=[\'"]?\\w+[\'"]?)\\]/' => '*[@\\1]',
       
// type and attribute exact value
       
'/(\\w)\\[(\\w+)\\=[\'"]?([\\w\\s]+)[\'"]?\\]/' => '\\1[@\\2="\\3"]',
       
// type and attribute value with ~ (one word within a whitespace-separated list of words)
       
'/([\\w\\*]+)\\[(\\w+)[\\s]*\\~\\=[\\s]*[\'"]?([\\w\\-_\\/]+)[\'"]?\\]/'
       
=> '\\1[contains(concat(" ", @\\2, " "), concat(" ", "\\3", " "))]',
       
// type and attribute value with | (either exact value match or prefix followed by a hyphen)
       
'/([\\w\\*]+)\\[(\\w+)[\\s]*\\|\\=[\\s]*[\'"]?([\\w\\-_\\s\\/]+)[\'"]?\\]/'
       
=> '\\1[@\\2="\\3" or starts-with(@\\2, concat("\\3", "-"))]',
       
// type and attribute value with ^ (prefix match)
       
'/([\\w\\*]+)\\[(\\w+)[\\s]*\\^\\=[\\s]*[\'"]?([\\w\\-_\\/]+)[\'"]?\\]/' => '\\1[starts-with(@\\2, "\\3")]',
       
// type and attribute value with * (substring match)
       
'/([\\w\\*]+)\\[(\\w+)[\\s]*\\*\\=[\\s]*[\'"]?([\\w\\-_\\s\\/:;]+)[\'"]?\\]/' => '\\1[contains(@\\2, "\\3")]',
       
// adjacent sibling
       
'/\\s*\\+\\s*/' => '/following-sibling::*[1]/self::',
       
// child
       
'/\\s*>\\s*/' => '/',
       
// descendant (don't match spaces within already translated XPath predicates)
       
'/\\s+(?![^\\[\\]]*+\\])/' => '//',
       
// type and :first-child
       
'/([^\\/]+):first-child/i' => '*[1]/self::\\1',
       
// type and :last-child
       
'/([^\\/]+):last-child/i' => '*[last()]/self::\\1',

       
// The following matcher will break things if it is placed before the adjacent matcher.
        // So one of the matchers matches either too much or not enough.
        // type and attribute value with $ (suffix match)
       
'/([\\w\\*]+)\\[(\\w+)[\\s]*\\$\\=[\\s]*[\'"]?([\\w\\-_\\s\\/]+)[\'"]?\\]/'
       
=> '\\1[substring(@\\2, string-length(@\\2) - string-length("\\3") + 1) = "\\3"]',
    ];

   
/**
     * Emogrifier will throw Exceptions when it encounters an error instead of silently ignoring them.
     *
     * @var bool
     */
   
private $debug = false;

   
/**
     * @param string $unprocessedHtml the HTML to process, must be UTF-8-encoded
     * @param string $css the CSS to merge, must be UTF-8-encoded
     */
   
public function __construct($unprocessedHtml = '', $css = '')
    {
        if (
$unprocessedHtml !== '') {
           
$this->setHtml($unprocessedHtml);
        }
       
$this->setCss($css);
    }

   
/**
     * Sets the HTML to process.
     *
     * @param string $html the HTML to process, must be UTF-encoded, must not be empty
     *
     * @return void
     *
     * @throws \InvalidArgumentException if $unprocessedHtml is anything other than a non-empty string
     */
   
public function setHtml($html)
    {
        if (!\
is_string($html)) {
            throw new \
InvalidArgumentException('The provided HTML must be a string.', 1540403913);
        }
        if (
$html === '') {
            throw new \
InvalidArgumentException('The provided HTML must not be empty.', 1540403910);
        }

       
$this->createUnifiedDomDocument($html);
    }

   
/**
     * Provides access to the internal DOMDocument representation of the HTML in its current state.
     *
     * @return \DOMDocument
     */
   
public function getDomDocument()
    {
        return
$this->domDocument;
    }

   
/**
     * Sets the CSS to merge with the HTML.
     *
     * @param string $css the CSS to merge, must be UTF-8-encoded
     *
     * @return void
     */
   
public function setCss($css)
    {
       
$this->css = $css;
    }

   
/**
     * Renders the normalized and processed HTML.
     *
     * @return string
     */
   
protected function render()
    {
       
$htmlWithPossibleErroneousClosingTags = $this->domDocument->saveHTML();

        return
$this->removeSelfClosingTagsClosingTags($htmlWithPossibleErroneousClosingTags);
    }

   
/**
     * Renders the content of the BODY element of the normalized and processed HTML.
     *
     * @return string
     */
   
protected function renderBodyContent()
    {
       
$htmlWithPossibleErroneousClosingTags = $this->domDocument->saveHTML($this->getBodyElement());
       
$bodyNodeHtml = $this->removeSelfClosingTagsClosingTags($htmlWithPossibleErroneousClosingTags);

        return \
preg_replace('%</?+body(?:\\s[^>]*+)?+>%', '', $bodyNodeHtml);
    }

   
/**
     * Eliminates any invalid closing tags for void elements from the given HTML.
     *
     * @param string $html
     *
     * @return string
     */
   
private function removeSelfClosingTagsClosingTags($html)
    {
        return \
preg_replace('%</' . self::PHP_UNRECOGNIZED_VOID_TAGNAME_MATCHER . '>%', '', $html);
    }

   
/**
     * Returns the BODY element.
     *
     * This method assumes that there always is a BODY element.
     *
     * @return \DOMElement
     */
   
private function getBodyElement()
    {
        return
$this->domDocument->getElementsByTagName('body')->item(0);
    }

   
/**
     * Returns the HEAD element.
     *
     * This method assumes that there always is a HEAD element.
     *
     * @return \DOMElement
     */
   
private function getHeadElement()
    {
        return
$this->domDocument->getElementsByTagName('head')->item(0);
    }

   
/**
     * Applies $this->css to the given HTML and returns the HTML with the CSS
     * applied.
     *
     * This method places the CSS inline.
     *
     * @return string
     *
     * @throws \BadMethodCallException
     */
   
public function emogrify()
    {
       
$this->assertExistenceOfHtml();

       
$this->process();

        return
$this->render();
    }

   
/**
     * Applies $this->css to the given HTML and returns only the HTML content
     * within the <body> tag.
     *
     * This method places the CSS inline.
     *
     * @return string
     *
     * @throws \BadMethodCallException
     */
   
public function emogrifyBodyContent()
    {
       
$this->assertExistenceOfHtml();

       
$this->process();

        return
$this->renderBodyContent();
    }

   
/**
     * Checks that some HTML has been set, and throws an exception otherwise.
     *
     * @return void
     *
     * @throws \BadMethodCallException
     */
   
private function assertExistenceOfHtml()
    {
        if (
$this->domDocument === null) {
            throw new \
BadMethodCallException('Please set some HTML first.', 1390393096);
        }
    }

   
/**
     * Creates a DOM document from the given HTML and stores it in $this->domDocument.
     *
     * The DOM document will always have a BODY element.
     *
     * @param string $html
     *
     * @return void
     */
   
private function createUnifiedDomDocument($html)
    {
       
$this->createRawDomDocument($html);
       
$this->ensureExistenceOfBodyElement();
    }

   
/**
     * Creates a DOMDocument instance from the given HTML and stores it in $this->domDocument.
     *
     * @param string $html
     *
     * @return void
     */
   
private function createRawDomDocument($html)
    {
       
$domDocument = new \DOMDocument();
       
$domDocument->strictErrorChecking = false;
       
$domDocument->formatOutput = true;
       
$libXmlState = \libxml_use_internal_errors(true);
       
$domDocument->loadHTML($this->prepareHtmlForDomConversion($html));
        \
libxml_clear_errors();
        \
libxml_use_internal_errors($libXmlState);

       
$this->domDocument = $domDocument;
       
$this->xPath = new \DOMXPath($this->domDocument);
    }

   
/**
     * Returns the HTML with added document type, Content-Type meta tag, and self-closing slashes, if needed,
     * ensuring that the HTML will be good for creating a DOM document from it.
     *
     * @param string $html
     *
     * @return string the unified HTML
     */
   
private function prepareHtmlForDomConversion($html)
    {
       
$htmlWithSelfClosingSlashes = $this->ensurePhpUnrecognizedSelfClosingTagsAreXml($html);
       
$htmlWithDocumentType = $this->ensureDocumentType($htmlWithSelfClosingSlashes);

        return
$this->addContentTypeMetaTag($htmlWithDocumentType);
    }

   
/**
     * Applies $this->css to $this->domDocument.
     *
     * This method places the CSS inline.
     *
     * @return void
     *
     * @throws \InvalidArgumentException
     */
   
protected function process()
    {
       
$this->clearAllCaches();
       
$this->purgeVisitedNodes();

        if (
PHP_MAJOR_VERSION >= 8)
        {
            \
set_error_handler([$this, 'handleXpathQueryWarningsPhp8'], E_WARNING);
        }
        else
        {
            \
set_error_handler([$this, 'handleXpathQueryWarnings'], E_WARNING);
        }

       
$this->removeUnprocessableTags();
       
$this->normalizeStyleAttributesOfAllNodes();

       
// grab any existing style blocks from the html and append them to the existing CSS
        // (these blocks should be appended so as to have precedence over conflicting styles in the existing CSS)
       
$allCss = $this->css;
        if (
$this->isStyleBlocksParsingEnabled) {
           
$allCss .= $this->getCssFromAllStyleNodes();
        }

       
$cssWithoutComments = $this->removeCssComments($allCss);
        list(
$cssWithoutCommentsCharsetOrImport, $cssImportRules)
            =
$this->extractImportAndCharsetRules($cssWithoutComments);

       
$excludedNodes = $this->getNodesToExclude();
       
$cssRules = $this->parseCssRules($cssWithoutCommentsCharsetOrImport);
        foreach (
$cssRules['inlinable'] as $cssRule) {
           
// There's no real way to test "PHP Warning" output generated by the following XPath query unless PHPUnit
            // converts it to an exception. Unfortunately, this would only apply to tests and not work for production
            // executions, which can still flood logs/output unnecessarily. Instead, Emogrifier's error handler should
            // always throw an exception and it must be caught here and only rethrown if in debug mode.
           
try {
               
// \DOMXPath::query will always return a DOMNodeList or throw an exception when errors are caught.
               
$nodesMatchingCssSelectors = $this->xPath->query($this->translateCssToXpath($cssRule['selector']));
            } catch (\
InvalidArgumentException $e) {
                if (
$this->debug) {
                    throw
$e;
                }
                continue;
            }

           
/** @var \DOMElement $node */
           
foreach ($nodesMatchingCssSelectors as $node) {
                if (\
in_array($node, $excludedNodes, true)) {
                    continue;
                }
               
$this->copyInlinableCssToStyleAttribute($node, $cssRule);
            }
        }

        if (
$this->isInlineStyleAttributesParsingEnabled) {
           
$this->fillStyleAttributesWithMergedStyles();
        }

       
$this->removeImportantAnnotationFromAllInlineStyles();

       
$this->copyUninlinableCssToStyleNode($cssRules['uninlinable'], $cssImportRules);

        \
restore_error_handler();
    }

   
/**
     * Searches for all nodes with a style attribute and removes the "!important" annotations out of
     * the inline style declarations, eventually by rearranging declarations.
     *
     * @return void
     */
   
private function removeImportantAnnotationFromAllInlineStyles()
    {
        foreach (
$this->getAllNodesWithStyleAttribute() as $node) {
           
$this->removeImportantAnnotationFromNodeInlineStyle($node);
        }
    }

   
/**
     * Removes the "!important" annotations out of the inline style declarations,
     * eventually by rearranging declarations.
     * Rearranging needed when !important shorthand properties are followed by some of their
     * not !important expanded-version properties.
     * For example "font: 12px serif !important; font-size: 13px;" must be reordered
     * to "font-size: 13px; font: 12px serif;" in order to remain correct.
     *
     * @param \DOMElement $node
     *
     * @return void
     */
   
private function removeImportantAnnotationFromNodeInlineStyle(\DOMElement $node)
    {
       
$inlineStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
       
$regularStyleDeclarations = [];
       
$importantStyleDeclarations = [];
        foreach (
$inlineStyleDeclarations as $property => $value) {
            if (
$this->attributeValueIsImportant($value)) {
               
$importantStyleDeclarations[$property] = \trim(\str_replace('!important', '', $value));
            } else {
               
$regularStyleDeclarations[$property] = $value;
            }
        }
       
$inlineStyleDeclarationsInNewOrder = \array_merge(
           
$regularStyleDeclarations,
           
$importantStyleDeclarations
       
);
       
$node->setAttribute(
           
'style',
           
$this->generateStyleStringFromSingleDeclarationsArray($inlineStyleDeclarationsInNewOrder)
        );
    }

   
/**
     * Returns a list with all DOM nodes that have a style attribute.
     *
     * @return \DOMNodeList
     */
   
private function getAllNodesWithStyleAttribute()
    {
        return
$this->xPath->query('//*[@style]');
    }

   
/**
     * Extracts and parses the individual rules from a CSS string.
     *
     * @param string $css a string of raw CSS code with comments removed
     *
     * @return string[][][] A 2-entry array with the key "inlinable" containing rules which can be inlined as `style`
     *         attributes and the key "uninlinable" containing rules which cannot.  Each value is an array of string
     *         sub-arrays with the keys
     *         "media" (the media query string, e.g. "@media screen and (max-width: 480px)",
     *         or an empty string if not from a `@media` rule),
     *         "selector" (the CSS selector, e.g., "*" or "header h1"),
     *         "hasUnmatchablePseudo" (true if that selector contains pseudo-elements or dynamic pseudo-classes
     *         such that the declarations cannot be applied inline),
     *         "declarationsBlock" (the semicolon-separated CSS declarations for that selector,
     *         e.g., "color: red; height: 4px;"),
     *         and "line" (the line number e.g. 42)
     */
   
private function parseCssRules($css)
    {
       
$cssKey = \md5($css);
        if (!isset(
$this->caches[self::CACHE_KEY_CSS][$cssKey])) {
           
$matches = $this->getCssRuleMatches($css);

           
$cssRules = [
               
'inlinable' => [],
               
'uninlinable' => [],
            ];
           
/** @var string[][] $matches */
            /** @var string[] $cssRule */
           
foreach ($matches as $key => $cssRule) {
               
$cssDeclaration = \trim($cssRule['declarations']);
                if (
$cssDeclaration === '') {
                    continue;
                }

                foreach (\
explode(',', $cssRule['selectors']) as $selector) {
                   
// don't process pseudo-elements and behavioral (dynamic) pseudo-classes;
                    // only allow structural pseudo-classes
                   
$hasPseudoElement = \strpos($selector, '::') !== false;
                   
$hasUnsupportedPseudoClass = (bool)\preg_match(
                       
'/:(?!' . self::PSEUDO_CLASS_MATCHER . ')[\\w\\-]/i',
                       
$selector
                   
);
                   
$hasUnmatchablePseudo = $hasPseudoElement || $hasUnsupportedPseudoClass;

                   
$parsedCssRule = [
                       
'media' => $cssRule['media'],
                       
'selector' => \trim($selector),
                       
'hasUnmatchablePseudo' => $hasUnmatchablePseudo,
                       
'declarationsBlock' => $cssDeclaration,
                       
// keep track of where it appears in the file, since order is important
                       
'line' => $key,
                    ];
                   
$ruleType = ($cssRule['media'] === '' && !$hasUnmatchablePseudo) ? 'inlinable' : 'uninlinable';
                   
$cssRules[$ruleType][] = $parsedCssRule;
                }
            }

            \
usort($cssRules['inlinable'], [$this, 'sortBySelectorPrecedence']);

           
$this->caches[self::CACHE_KEY_CSS][$cssKey] = $cssRules;
        }

        return
$this->caches[self::CACHE_KEY_CSS][$cssKey];
    }

   
/**
     * Parses a string of CSS into the media query, selectors and declarations for each ruleset in order.
     *
     * @param string $css CSS with comments removed
     *
     * @return string[][] Array of string sub-arrays with the keys
     *         "media" (the media query string, e.g. "@media screen and (max-width: 480px)",
     *         or an empty string if not from an `@media` rule),
     *         "selectors" (the CSS selector(s), e.g., "*" or "h1, h2"),
     *         "declarations" (the semicolon-separated CSS declarations for that/those selector(s),
     *         e.g., "color: red; height: 4px;"),
     */
   
private function getCssRuleMatches($css)
    {
       
$splitCss = $this->splitCssAndMediaQuery($css);

       
$ruleMatches = [];
        foreach (
$splitCss as $cssPart) {
           
// process each part for selectors and definitions
           
\preg_match_all('/(?:^|[\\s^{}]*)([^{]+){([^}]*)}/mi', $cssPart['css'], $matches, PREG_SET_ORDER);

           
/** @var string[][] $matches */
           
foreach ($matches as $cssRule) {
               
$ruleMatches[] = [
                   
'media' => $cssPart['media'],
                   
'selectors' => $cssRule[1],
                   
'declarations' => $cssRule[2],
                ];
            }
        }

        return
$ruleMatches;
    }

   
/**
     * Disables the parsing of inline styles.
     *
     * @return void
     */
   
public function disableInlineStyleAttributesParsing()
    {
       
$this->isInlineStyleAttributesParsingEnabled = false;
    }

   
/**
     * Disables the parsing of <style> blocks.
     *
     * @return void
     */
   
public function disableStyleBlocksParsing()
    {
       
$this->isStyleBlocksParsingEnabled = false;
    }

   
/**
     * Clears all caches.
     *
     * @return void
     */
   
private function clearAllCaches()
    {
       
$this->caches = [
           
self::CACHE_KEY_CSS => [],
           
self::CACHE_KEY_SELECTOR => [],
           
self::CACHE_KEY_XPATH => [],
           
self::CACHE_KEY_CSS_DECLARATIONS_BLOCK => [],
           
self::CACHE_KEY_COMBINED_STYLES => [],
        ];
    }

   
/**
     * Purges the visited nodes.
     *
     * @return void
     */
   
private function purgeVisitedNodes()
    {
       
$this->visitedNodes = [];
       
$this->styleAttributesForNodes = [];
    }

   
/**
     * Marks a tag for removal.
     *
     * There are some HTML tags that DOMDocument cannot process, and it will throw an error if it encounters them.
     * In particular, DOMDocument will complain if you try to use HTML5 tags in an XHTML document.
     *
     * Note: The tags will not be removed if they have any content.
     *
     * @param string $tagName the tag name, e.g., "p"
     *
     * @return void
     */
   
public function addUnprocessableHtmlTag($tagName)
    {
       
$this->unprocessableHtmlTags[] = $tagName;
    }

   
/**
     * Drops a tag from the removal list.
     *
     * @param string $tagName the tag name, e.g., "p"
     *
     * @return void
     */
   
public function removeUnprocessableHtmlTag($tagName)
    {
       
$key = \array_search($tagName, $this->unprocessableHtmlTags, true);
        if (
$key !== false) {
           
/** @var int|string $key */
           
unset($this->unprocessableHtmlTags[$key]);
        }
    }

   
/**
     * Marks a media query type to keep.
     *
     * @param string $mediaName the media type name, e.g., "braille"
     *
     * @return void
     */
   
public function addAllowedMediaType($mediaName)
    {
       
$this->allowedMediaTypes[$mediaName] = true;
    }

   
/**
     * Drops a media query type from the allowed list.
     *
     * @param string $mediaName the tag name, e.g., "braille"
     *
     * @return void
     */
   
public function removeAllowedMediaType($mediaName)
    {
        if (isset(
$this->allowedMediaTypes[$mediaName])) {
            unset(
$this->allowedMediaTypes[$mediaName]);
        }
    }

   
/**
     * Adds a selector to exclude nodes from emogrification.
     *
     * Any nodes that match the selector will not have their style altered.
     *
     * @param string $selector the selector to exclude, e.g., ".editor"
     *
     * @return void
     */
   
public function addExcludedSelector($selector)
    {
       
$this->excludedSelectors[$selector] = true;
    }

   
/**
     * No longer excludes the nodes matching this selector from emogrification.
     *
     * @param string $selector the selector to no longer exclude, e.g., ".editor"
     *
     * @return void
     */
   
public function removeExcludedSelector($selector)
    {
        if (isset(
$this->excludedSelectors[$selector])) {
            unset(
$this->excludedSelectors[$selector]);
        }
    }

   
/**
     * Parses the document and normalizes all existing CSS attributes.
     * This changes 'DISPLAY: none' to 'display: none'.
     * We wouldn't have to do this if DOMXPath supported XPath 2.0.
     * Also stores a reference of nodes with existing inline styles so we don't overwrite them.
     *
     * @return void
     */
   
private function normalizeStyleAttributesOfAllNodes()
    {
       
/** @var \DOMElement $node */
       
foreach ($this->getAllNodesWithStyleAttribute() as $node) {
            if (
$this->isInlineStyleAttributesParsingEnabled) {
               
$this->normalizeStyleAttributes($node);
            }
           
// Remove style attribute in every case, so we can add them back (if inline style attributes
            // parsing is enabled) to the end of the style list, thus keeping the right priority of CSS rules;
            // else original inline style rules may remain at the beginning of the final inline style definition
            // of a node, which may give not the desired results
           
$node->removeAttribute('style');
        }
    }

   
/**
     * Normalizes the value of the "style" attribute and saves it.
     *
     * @param \DOMElement $node
     *
     * @return void
     */
   
private function normalizeStyleAttributes(\DOMElement $node)
    {
       
$normalizedOriginalStyle = \preg_replace_callback(
           
'/-?+[_a-zA-Z][\\w\\-]*+(?=:)/S',
            static function (array
$m) {
                return \
strtolower($m[0]);
            },
           
$node->getAttribute('style')
        );

       
// in order to not overwrite existing style attributes in the HTML, we
        // have to save the original HTML styles
       
$nodePath = $node->getNodePath();
        if (!isset(
$this->styleAttributesForNodes[$nodePath])) {
           
$this->styleAttributesForNodes[$nodePath] = $this->parseCssDeclarationsBlock($normalizedOriginalStyle);
           
$this->visitedNodes[$nodePath] = $node;
        }

       
$node->setAttribute('style', $normalizedOriginalStyle);
    }

   
/**
     * Merges styles from styles attributes and style nodes and applies them to the attribute nodes
     *
     * @return void
     */
   
private function fillStyleAttributesWithMergedStyles()
    {
        foreach (
$this->styleAttributesForNodes as $nodePath => $styleAttributesForNode) {
           
$node = $this->visitedNodes[$nodePath];
           
$currentStyleAttributes = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
           
$node->setAttribute(
               
'style',
               
$this->generateStyleStringFromDeclarationsArrays(
                   
$currentStyleAttributes,
                   
$styleAttributesForNode
               
)
            );
        }
    }

   
/**
     * This method merges old or existing name/value array with new name/value array
     * and then generates a string of the combined style suitable for placing inline.
     * This becomes the single point for CSS string generation allowing for consistent
     * CSS output no matter where the CSS originally came from.
     *
     * @param string[] $oldStyles
     * @param string[] $newStyles
     *
     * @return string
     */
   
private function generateStyleStringFromDeclarationsArrays(array $oldStyles, array $newStyles)
    {
       
$cacheKey = \serialize([$oldStyles, $newStyles]);
        if (isset(
$this->caches[self::CACHE_KEY_COMBINED_STYLES][$cacheKey])) {
            return
$this->caches[self::CACHE_KEY_COMBINED_STYLES][$cacheKey];
        }

       
// Unset the overridden styles to preserve order, important if shorthand and individual properties are mixed
       
foreach ($oldStyles as $attributeName => $attributeValue) {
            if (!isset(
$newStyles[$attributeName])) {
                continue;
            }

           
$newAttributeValue = $newStyles[$attributeName];
            if (
               
$this->attributeValueIsImportant($attributeValue)
                && !
$this->attributeValueIsImportant($newAttributeValue)
            ) {
                unset(
$newStyles[$attributeName]);
            } else {
                unset(
$oldStyles[$attributeName]);
            }
        }

       
$combinedStyles = \array_merge($oldStyles, $newStyles);

       
$style = '';
        foreach (
$combinedStyles as $attributeName => $attributeValue) {
           
$style .= \strtolower(\trim($attributeName)) . ': ' . \trim($attributeValue) . '; ';
        }
       
$trimmedStyle = \rtrim($style);

       
$this->caches[self::CACHE_KEY_COMBINED_STYLES][$cacheKey] = $trimmedStyle;

        return
$trimmedStyle;
    }

   
/**
     * Generates a CSS style string suitable to be used inline from the $styleDeclarations property => value array.
     *
     * @param string[] $styleDeclarations
     *
     * @return string
     */
   
private function generateStyleStringFromSingleDeclarationsArray(array $styleDeclarations)
    {
        return
$this->generateStyleStringFromDeclarationsArrays([], $styleDeclarations);
    }

   
/**
     * Checks whether $attributeValue is marked as !important.
     *
     * @param string $attributeValue
     *
     * @return bool
     */
   
private function attributeValueIsImportant($attributeValue)
    {
        return \
strtolower(\substr(\trim($attributeValue), -10)) === '!important';
    }

   
/**
     * Copies $cssRule into the style attribute of $node.
     *
     * Note: This method does not check whether $cssRule matches $node.
     *
     * @param \DOMElement $node
     * @param string[][] $cssRule
     *
     * @return void
     */
   
private function copyInlinableCssToStyleAttribute(\DOMElement $node, array $cssRule)
    {
       
$newStyleDeclarations = $this->parseCssDeclarationsBlock($cssRule['declarationsBlock']);
        if (
$newStyleDeclarations === []) {
            return;
        }

       
// if it has a style attribute, get it, process it, and append (overwrite) new stuff
       
if ($node->hasAttribute('style')) {
           
// break it up into an associative array
           
$oldStyleDeclarations = $this->parseCssDeclarationsBlock($node->getAttribute('style'));
        } else {
           
$oldStyleDeclarations = [];
        }
       
$node->setAttribute(
           
'style',
           
$this->generateStyleStringFromDeclarationsArrays($oldStyleDeclarations, $newStyleDeclarations)
        );
    }

   
/**
     * Applies $cssRules to $this->domDocument, limited to the rules that actually apply to the document, by placing
     * them as CSS in a `<style>` element.
     *
     * @param string[][] $cssRules the "uninlinable" array of CSS rules returned by `parseCssRules`
     * @param string $cssImportRules This may contain any `@import` rules that should precede the CSS placed in the
     *        `<style>` element.  If there are no unlinlinable CSS rules to copy there, a `<style>` element will be
     *        created containing just `$cssImportRules`.  `$cssImportRules` may be an empty string; if it is, and there
     *        are no unlinlinable CSS rules, an empty `<style>` element will not be created.
     *
     * @return void
     */
   
private function copyUninlinableCssToStyleNode(array $cssRules, $cssImportRules)
    {
       
$css = $cssImportRules;

       
$cssRulesRelevantForDocument = \array_filter($cssRules, [$this, 'existsMatchForSelectorInCssRule']);

       
// avoid including unneeded class dependency if there are no rules
       
if ($cssRulesRelevantForDocument !== []) {
           
// support use without autoload
           
if (!\class_exists(CssConcatenator::class)) {
                require_once
__DIR__ . '/Emogrifier/Utilities/CssConcatenator.php';
            }

           
$cssConcatenator = new CssConcatenator();
            foreach (
$cssRulesRelevantForDocument as $cssRule) {
               
$cssConcatenator->append([$cssRule['selector']], $cssRule['declarationsBlock'], $cssRule['media']);
            }

           
$css .= $cssConcatenator->getCss();
        }

       
// avoid adding empty style element
       
if ($css !== '') {
           
$this->addStyleElementToDocument($css);
        }
    }

   
/**
     * Checks whether there is at least one matching element for the CSS selector contained in the `selector` element
     * of the provided CSS rule.
     *
     * Any dynamic pseudo-classes will be assumed to apply. If the selector matches a pseudo-element,
     * it will test for a match with its originating element.
     *
     * @param string[] $cssRule
     *
     * @return bool
     *
     * @throws \InvalidArgumentException
     */
   
private function existsMatchForSelectorInCssRule(array $cssRule)
    {
       
$selector = $cssRule['selector'];
        if (
$cssRule['hasUnmatchablePseudo']) {
           
$selector = $this->removeUnmatchablePseudoComponents($selector);
        }
        return
$this->existsMatchForCssSelector($selector);
    }

   
/**
     * Removes pseudo-elements and dynamic pseudo-classes from a CSS selector, replacing them with "*" if necessary.
     * If such a pseudo-component is within the argument of `:not`, the entire `:not` component is removed or replaced.
     *
     * @param string $selector
     *
     * @return string Selector which will match the relevant DOM elements if the pseudo-classes are assumed to apply,
     *                or in the case of pseudo-elements will match their originating element.
     */
   
private function removeUnmatchablePseudoComponents($selector)
    {
       
// The regex allows nested brackets via `(?2)`.
        // A space is temporarily prepended because the callback can't determine if the match was at the very start.
       
$selectorWithoutNots = \ltrim(\preg_replace_callback(
           
'/(\\s?+):not(\\([^()]*+(?:(?2)[^()]*+)*+\\))/i',
            [
$this, 'replaceUnmatchableNotComponent'],
           
' ' . $selector
       
));

       
$pseudoComponentMatcher = ':(?!' . self::PSEUDO_CLASS_MATCHER . '):?+[\\w\\-]++(?:\\([^\\)]*+\\))?+';
        return \
preg_replace(
            [
'/(\\s|^)' . $pseudoComponentMatcher . '/i', '/' . $pseudoComponentMatcher . '/i'],
            [
'$1*', ''],
           
$selectorWithoutNots
       
);
    }

   
/**
     * Helps `removeUnmatchablePseudoComponents()` replace or remove a selector `:not(...)` component if its argument
     * contains pseudo-elements or dynamic pseudo-classes.
     *
     * @param string[] $matches array of elements matched by the regular expression
     *
     * @return string the full match if there were no unmatchable pseudo components within; otherwise, any preceding
     *         whitespace followed by "*", or an empty string if there was no preceding whitespace
     */
   
private function replaceUnmatchableNotComponent(array $matches)
    {
        list(
$notComponentWithAnyPrecedingWhitespace, $anyPrecedingWhitespace, $notArgumentInBrackets) = $matches;

       
$hasUnmatchablePseudo = \preg_match(
           
'/:(?!' . self::PSEUDO_CLASS_MATCHER . ')[\\w\\-:]/i',
           
$notArgumentInBrackets
       
);

        if (
$hasUnmatchablePseudo) {
            return
$anyPrecedingWhitespace !== '' ? $anyPrecedingWhitespace . '*' : '';
        }
        return
$notComponentWithAnyPrecedingWhitespace;
    }

   
/**
     * Checks whether there is at least one matching element for $cssSelector.
     * When not in debug mode, it returns true also for invalid selectors (because they may be valid,
     * just not implemented/recognized yet by Emogrifier).
     *
     * @param string $cssSelector
     *
     * @return bool
     *
     * @throws \InvalidArgumentException
     */
   
private function existsMatchForCssSelector($cssSelector)
    {
        try {
           
$nodesMatchingSelector = $this->xPath->query($this->translateCssToXpath($cssSelector));
        } catch (\
InvalidArgumentException $e) {
            if (
$this->debug) {
                throw
$e;
            }
            return
true;
        }

        return
$nodesMatchingSelector !== false && $nodesMatchingSelector->length !== 0;
    }

   
/**
     * Returns CSS content.
     *
     * @return string
     */
   
private function getCssFromAllStyleNodes()
    {
       
$styleNodes = $this->xPath->query('//style');

        if (
$styleNodes === false) {
            return
'';
        }

       
$css = '';
       
/** @var \DOMNode $styleNode */
       
foreach ($styleNodes as $styleNode) {
           
$css .= "\n\n" . $styleNode->nodeValue;
           
$styleNode->parentNode->removeChild($styleNode);
        }

        return
$css;
    }

   
/**
     * Adds a style element with $css to $this->domDocument.
     *
     * This method is protected to allow overriding.
     *
     * @see https://github.com/MyIntervals/emogrifier/issues/103
     *
     * @param string $css
     *
     * @return void
     */
   
protected function addStyleElementToDocument($css)
    {
       
$styleElement = $this->domDocument->createElement('style', $css);
       
$styleAttribute = $this->domDocument->createAttribute('type');
       
$styleAttribute->value = 'text/css';
       
$styleElement->appendChild($styleAttribute);

       
$headElement = $this->getHeadElement();
       
$headElement->appendChild($styleElement);
    }

   
/**
     * Checks that $this->domDocument has a BODY element and adds it if it is missing.
     *
     * @return void
     *
     * @throws \UnexpectedValueException
     */
   
private function ensureExistenceOfBodyElement()
    {
        if (
$this->domDocument->getElementsByTagName('body')->item(0) !== null) {
            return;
        }

       
$htmlElement = $this->domDocument->getElementsByTagName('html')->item(0);
        if (
$htmlElement === null) {
            throw new \
UnexpectedValueException('There is no HTML element although there should be one.', 1569930874);
        }
       
$htmlElement->appendChild($this->domDocument->createElement('body'));
    }

   
/**
     * Removes comments from the supplied CSS.
     *
     * @param string $css
     *
     * @return string CSS with the comments removed
     */
   
private function removeCssComments($css)
    {
        return \
preg_replace('%/\\*[^*]*+(?:\\*(?!/)[^*]*+)*+\\*/%', '', $css);
    }

   
/**
     * Extracts `@import` and `@charset` rules from the supplied CSS.  These rules must not be preceded by any other
     * rules, or they will be ignored.  (From the CSS 2.1 specification: "CSS 2.1 user agents must ignore any '@import'
     * rule that occurs inside a block or after any non-ignored statement other than an @charset or an @import rule."
     * Note also that `@charset` is case sensitive whereas `@import` is not.)
     *
     * @param string $css CSS with comments removed
     *
     * @return string[] The first element is the CSS with the valid `@import` and `@charset` rules removed.  The second
     * element contains a concatenation of the valid `@import` rules, each followed by whatever whitespace followed it
     * in the original CSS (so that either unminified or minified formatting is preserved); if there were no `@import`
     * rules, it will be an empty string.  The (valid) `@charset` rules are discarded.
     */
   
private function extractImportAndCharsetRules($css)
    {
       
$possiblyModifiedCss = $css;
       
$importRules = '';

        while (
            \
preg_match(
               
'/^\\s*+(@((?i)import(?-i)|charset)\\s[^;]++;\\s*+)/',
               
$possiblyModifiedCss,
               
$matches
           
)
        ) {
            list(
$fullMatch, $atRuleAndFollowingWhitespace, $atRuleName) = $matches;

            if (\
strtolower($atRuleName) === 'import') {
               
$importRules .= $atRuleAndFollowingWhitespace;
            }

           
$possiblyModifiedCss = \substr($possiblyModifiedCss, \strlen($fullMatch));
        }

        return [
$possiblyModifiedCss, $importRules];
    }

   
/**
     * Splits input CSS code into an array of parts for different media queries, in order.
     * Each part is an array where:
     *
     * - key "css" will contain clean CSS code (for @media rules this will be the group rule body within "{...}")
     * - key "media" will contain "@media " followed by the media query list, for all allowed media queries,
     *   or an empty string for CSS not within a media query
     *
     * Example:
     *
     * The CSS code
     *
     *   "@import "file.css"; h1 { color:red; } @media { h1 {}} @media tv { h1 {}}"
     *
     * will be parsed into the following array:
     *
     *   0 => [
     *     "css" => "h1 { color:red; }",
     *     "media" => ""
     *   ],
     *   1 => [
     *     "css" => " h1 {}",
     *     "media" => "@media "
     *   ]
     *
     * @param string $css
     *
     * @return string[][]
     */
   
private function splitCssAndMediaQuery($css)
    {
       
$mediaTypesExpression = '';
        if (!empty(
$this->allowedMediaTypes)) {
           
$mediaTypesExpression = '|' . \implode('|', \array_keys($this->allowedMediaTypes));
        }

       
$mediaRuleBodyMatcher = '[^{]*+{(?:[^{}]*+{.*})?\\s*+}\\s*+';

       
$cssSplitForAllowedMediaTypes = \preg_split(
           
'#(@media\\s++(?:only\\s++)?+(?:(?=[{(])' . $mediaTypesExpression . ')' . $mediaRuleBodyMatcher
           
. ')#misU',
           
$css,
            -
1,
           
PREG_SPLIT_DELIM_CAPTURE
       
);

       
// filter the CSS outside/between allowed @media rules
       
$cssCleaningMatchers = [
           
'import/charset directives' => '/\\s*+@(?:import|charset)\\s[^;]++;/i',
           
'remaining media enclosures' => '/\\s*+@media\\s' . $mediaRuleBodyMatcher . '/isU',
        ];

       
$splitCss = [];
        foreach (
$cssSplitForAllowedMediaTypes as $index => $cssPart) {
           
$isMediaRule = $index % 2 !== 0;
            if (
$isMediaRule) {
                \
preg_match('/^([^{]*+){(.*)}[^}]*+$/s', $cssPart, $matches);
               
$splitCss[] = [
                   
'css' => $matches[2],
                   
'media' => $matches[1],
                ];
            } else {
               
$cleanedCss = \trim(\preg_replace($cssCleaningMatchers, '', $cssPart));
                if (
$cleanedCss !== '') {
                   
$splitCss[] = [
                       
'css' => $cleanedCss,
                       
'media' => '',
                    ];
                }
            }
        }
        return
$splitCss;
    }

   
/**
     * Removes empty unprocessable tags from the DOM document.
     *
     * @return void
     */
   
private function removeUnprocessableTags()
    {
        foreach (
$this->unprocessableHtmlTags as $tagName) {
           
// Deleting nodes from a 'live' NodeList invalidates iteration on it, so a copy must be made to iterate.
           
$nodes = [];
            foreach (
$this->domDocument->getElementsByTagName($tagName) as $node) {
               
$nodes[] = $node;
            }
           
/** @var \DOMNode $node */
           
foreach ($nodes as $node) {
                if (!
$node->hasChildNodes()) {
                   
$node->parentNode->removeChild($node);
                }
            }
        }
    }

   
/**
     * Makes sure that the passed HTML has a document type.
     *
     * @param string $html
     *
     * @return string HTML with document type
     */
   
private function ensureDocumentType($html)
    {
       
$hasDocumentType = \stripos($html, '<!DOCTYPE') !== false;
        if (
$hasDocumentType) {
            return
$html;
        }

        return
self::DEFAULT_DOCUMENT_TYPE . $html;
    }

   
/**
     * Adds a Content-Type meta tag for the charset.
     *
     * This method also ensures that there is a HEAD element.
     *
     * @param string $html
     *
     * @return string the HTML with the meta tag added
     */
   
private function addContentTypeMetaTag($html)
    {
       
$hasContentTypeMetaTag = \stripos($html, 'Content-Type') !== false;
        if (
$hasContentTypeMetaTag) {
            return
$html;
        }

       
// We are trying to insert the meta tag to the right spot in the DOM.
        // If we just prepended it to the HTML, we would lose attributes set to the HTML tag.
       
$hasHeadTag = \stripos($html, '<head') !== false;
       
$hasHtmlTag = \stripos($html, '<html') !== false;

        if (
$hasHeadTag) {
           
$reworkedHtml = \preg_replace('/<head(.*?)>/i', '<head$1>' . self::CONTENT_TYPE_META_TAG, $html);
        } elseif (
$hasHtmlTag) {
           
$reworkedHtml = \preg_replace(
               
'/<html(.*?)>/i',
               
'<html$1><head>' . self::CONTENT_TYPE_META_TAG . '</head>',
               
$html
           
);
        } else {
           
$reworkedHtml = self::CONTENT_TYPE_META_TAG . $html;
        }

        return
$reworkedHtml;
    }

   
/**
     * Makes sure that any self-closing tags not recognized as such by PHP's DOMDocument implementation have a
     * self-closing slash.
     *
     * @param string $html
     *
     * @return string HTML with problematic tags converted.
     */
   
private function ensurePhpUnrecognizedSelfClosingTagsAreXml($html)
    {
        return \
preg_replace(
           
'%<' . self::PHP_UNRECOGNIZED_VOID_TAGNAME_MATCHER . '\\b[^>]*+(?<!/)(?=>)%',
           
'$0/',
           
$html
       
);
    }

   
/**
     * @param string[] $a
     * @param string[] $b
     *
     * @return int
     */
   
private function sortBySelectorPrecedence(array $a, array $b)
    {
       
$precedenceA = $this->getCssSelectorPrecedence($a['selector']);
       
$precedenceB = $this->getCssSelectorPrecedence($b['selector']);

       
// We want these sorted in ascending order so selectors with lesser precedence get processed first and
        // selectors with greater precedence get sorted last.
       
$precedenceForEquals = ($a['line'] < $b['line'] ? -1 : 1);
       
$precedenceForNotEquals = ($precedenceA < $precedenceB ? -1 : 1);
        return (
$precedenceA === $precedenceB) ? $precedenceForEquals : $precedenceForNotEquals;
    }

   
/**
     * @param string $selector
     *
     * @return int
     */
   
private function getCssSelectorPrecedence($selector)
    {
       
$selectorKey = \md5($selector);
        if (!isset(
$this->caches[self::CACHE_KEY_SELECTOR][$selectorKey])) {
           
$precedence = 0;
            foreach (
$this->selectorPrecedenceMatchers as $matcher => $value) {
                if (\
trim($selector) === '') {
                    break;
                }
               
$number = 0;
               
$selector = \preg_replace('/' . $matcher . '\\w+/', '', $selector, -1, $number);
               
$precedence += ($value * $number);
            }
           
$this->caches[self::CACHE_KEY_SELECTOR][$selectorKey] = $precedence;
        }

        return
$this->caches[self::CACHE_KEY_SELECTOR][$selectorKey];
    }

   
/**
     * Maps a CSS selector to an XPath query string.
     *
     * @see http://plasmasturm.org/log/444/
     *
     * @param string $cssSelector a CSS selector
     *
     * @return string the corresponding XPath selector
     */
   
private function translateCssToXpath($cssSelector)
    {
       
$paddedSelector = ' ' . $cssSelector . ' ';
       
$lowercasePaddedSelector = \preg_replace_callback(
           
'/\\s+\\w+\\s+/',
            static function (array
$matches) {
                return \
strtolower($matches[0]);
            },
           
$paddedSelector
       
);
       
$trimmedLowercaseSelector = \trim($lowercasePaddedSelector);
       
$xPathKey = \md5($trimmedLowercaseSelector);
        if (isset(
$this->caches[self::CACHE_KEY_XPATH][$xPathKey])) {
            return
$this->caches[self::CACHE_KEY_SELECTOR][$xPathKey];
        }

       
$hasNotSelector = (bool)\preg_match(
           
'/^([^:]+):not\\(\\s*([[:ascii:]]+)\\s*\\)$/',
           
$trimmedLowercaseSelector,
           
$matches
       
);
        if (
$hasNotSelector) {
           
/** @var string[] $matches */
           
list(, $partBeforeNot, $notContents) = $matches;
           
$xPath = '//' . $this->translateCssToXpathPass($partBeforeNot) .
               
'[not(' . $this->translateCssToXpathPassInline($notContents) . ')]';
        } else {
           
$xPath = '//' . $this->translateCssToXpathPass($trimmedLowercaseSelector);
        }
       
$this->caches[self::CACHE_KEY_SELECTOR][$xPathKey] = $xPath;

        return
$this->caches[self::CACHE_KEY_SELECTOR][$xPathKey];
    }

   
/**
     * Flexibly translates the CSS selector $trimmedLowercaseSelector to an xPath selector.
     *
     * @param string $trimmedLowercaseSelector
     *
     * @return string
     */
   
private function translateCssToXpathPass($trimmedLowercaseSelector)
    {
        return
$this->translateCssToXpathPassWithMatchClassAttributesCallback(
           
$trimmedLowercaseSelector,
            [
$this, 'matchClassAttributes']
        );
    }

   
/**
     * Flexibly translates the CSS selector $trimmedLowercaseSelector to an xPath selector for inline usage.
     *
     * @param string $trimmedLowercaseSelector
     *
     * @return string
     */
   
private function translateCssToXpathPassInline($trimmedLowercaseSelector)
    {
        return
$this->translateCssToXpathPassWithMatchClassAttributesCallback(
           
$trimmedLowercaseSelector,
            [
$this, 'matchClassAttributesInline']
        );
    }

   
/**
     * Flexibly translates the CSS selector $trimmedLowercaseSelector to an xPath selector while using
     * $matchClassAttributesCallback as to match the class attributes.
     *
     * @param string $trimmedLowercaseSelector
     * @param callable $matchClassAttributesCallback
     *
     * @return string
     */
   
private function translateCssToXpathPassWithMatchClassAttributesCallback(
       
$trimmedLowercaseSelector,
        callable
$matchClassAttributesCallback
   
) {
        if (
preg_match('/^\\[[\w-]+\\*=/', $trimmedLowercaseSelector))
        {
           
$trimmedLowercaseSelector = '*' . $trimmedLowercaseSelector;
        }

       
$roughXpath = \preg_replace(\array_keys($this->xPathRules), $this->xPathRules, $trimmedLowercaseSelector);
       
$xPathWithIdAttributeMatchers = \preg_replace_callback(
           
self::ID_ATTRIBUTE_MATCHER,
            [
$this, 'matchIdAttributes'],
           
$roughXpath
       
);
       
$xPathWithIdAttributeAndClassMatchers = \preg_replace_callback(
           
self::CLASS_ATTRIBUTE_MATCHER,
           
$matchClassAttributesCallback,
           
$xPathWithIdAttributeMatchers
       
);

       
// Advanced selectors are going to require a bit more advanced emogrification.
       
$xPathWithIdAttributeAndClassMatchers = \preg_replace_callback(
           
'/([^\\/]+):nth-child\\(\\s*(odd|even|[+\\-]?\\d|[+\\-]?\\d?n(\\s*[+\\-]\\s*\\d)?)\\s*\\)/i',
            [
$this, 'translateNthChild'],
           
$xPathWithIdAttributeAndClassMatchers
       
);
       
$finalXpath = \preg_replace_callback(
           
'/([^\\/]+):nth-of-type\\(\\s*(odd|even|[+\\-]?\\d|[+\\-]?\\d?n(\\s*[+\\-]\\s*\\d)?)\\s*\\)/i',
            [
$this, 'translateNthOfType'],
           
$xPathWithIdAttributeAndClassMatchers
       
);

        return
$finalXpath;
    }

   
/**
     * @param string[] $match
     *
     * @return string
     */
   
private function matchIdAttributes(array $match)
    {
        return (
$match[1] !== '' ? $match[1] : '*') . '[@id="' . $match[2] . '"]';
    }

   
/**
     * @param string[] $match
     *
     * @return string xPath class attribute query wrapped in element selector
     */
   
private function matchClassAttributes(array $match)
    {
        return (
$match[1] !== '' ? $match[1] : '*') . '[' . $this->matchClassAttributesInline($match) . ']';
    }

   
/**
     * @param string[] $match
     *
     * @return string xPath class attribute query
     */
   
private function matchClassAttributesInline(array $match)
    {
        return
'contains(concat(" ",@class," "),concat(" ","' .
            \
str_replace('.', '"," "))][contains(concat(" ",@class," "),concat(" ","', \substr($match[2], 1)) .
           
'"," "))';
    }

   
/**
     * @param string[] $match
     *
     * @return string
     */
   
private function translateNthChild(array $match)
    {
       
$parseResult = $this->parseNth($match);

        if (isset(
$parseResult[self::MULTIPLIER])) {
            if (
$parseResult[self::MULTIPLIER] < 0) {
               
$parseResult[self::MULTIPLIER] = \abs($parseResult[self::MULTIPLIER]);
               
$xPathExpression = \sprintf(
                   
'*[(last() - position()) mod %1%u = %2$u]/self::%3$s',
                   
$parseResult[self::MULTIPLIER],
                   
$parseResult[self::INDEX],
                   
$match[1]
                );
            } else {
               
$xPathExpression = \sprintf(
                   
'*[position() mod %1$u = %2$u]/self::%3$s',
                   
$parseResult[self::MULTIPLIER],
                   
$parseResult[self::INDEX],
                   
$match[1]
                );
            }
        } else {
           
$xPathExpression = \sprintf('*[%1$u]/self::%2$s', $parseResult[self::INDEX], $match[1]);
        }

        return
$xPathExpression;
    }

   
/**
     * @param string[] $match
     *
     * @return string
     */
   
private function translateNthOfType(array $match)
    {
       
$parseResult = $this->parseNth($match);

        if (isset(
$parseResult[self::MULTIPLIER])) {
            if (
$parseResult[self::MULTIPLIER] < 0) {
               
$parseResult[self::MULTIPLIER] = \abs($parseResult[self::MULTIPLIER]);
               
$xPathExpression = \sprintf(
                   
'%1$s[(last() - position()) mod %2$u = %3$u]',
                   
$match[1],
                   
$parseResult[self::MULTIPLIER],
                   
$parseResult[self::INDEX]
                );
            } else {
               
$xPathExpression = \sprintf(
                   
'%1$s[position() mod %2$u = %3$u]',
                   
$match[1],
                   
$parseResult[self::MULTIPLIER],
                   
$parseResult[self::INDEX]
                );
            }
        } else {
           
$xPathExpression = \sprintf('%1$s[%2$u]', $match[1], $parseResult[self::INDEX]);
        }

        return
$xPathExpression;
    }

   
/**
     * @param string[] $match
     *
     * @return int[]
     */
   
private function parseNth(array $match)
    {
        if (\
in_array(\strtolower($match[2]), ['even', 'odd'], true)) {
           
// we have "even" or "odd"
           
$index = \strtolower($match[2]) === 'even' ? 0 : 1;
            return [
self::MULTIPLIER => 2, self::INDEX => $index];
        }
        if (\
stripos($match[2], 'n') === false) {
           
// if there is a multiplier
           
$index = (int)\str_replace(' ', '', $match[2]);
            return [
self::INDEX => $index];
        }

        if (isset(
$match[3])) {
           
$multipleTerm = \str_replace($match[3], '', $match[2]);
           
$index = (int)\str_replace(' ', '', $match[3]);
        } else {
           
$multipleTerm = $match[2];
           
$index = 0;
        }

       
$multiplier = \str_ireplace('n', '', $multipleTerm);

        if (
$multiplier === '') {
           
$multiplier = 1;
        } elseif (
$multiplier === '0') {
            return [
self::INDEX => $index];
        } else {
           
$multiplier = (int)$multiplier;
        }

        while (
$index < 0) {
           
$index += \abs($multiplier);
        }

        return [
self::MULTIPLIER => $multiplier, self::INDEX => $index];
    }

   
/**
     * Parses a CSS declaration block into property name/value pairs.
     *
     * Example:
     *
     * The declaration block
     *
     *   "color: #000; font-weight: bold;"
     *
     * will be parsed into the following array:
     *
     *   "color" => "#000"
     *   "font-weight" => "bold"
     *
     * @param string $cssDeclarationsBlock the CSS declarations block without the curly braces, may be empty
     *
     * @return string[]
     *         the CSS declarations with the property names as array keys and the property values as array values
     */
   
private function parseCssDeclarationsBlock($cssDeclarationsBlock)
    {
        if (isset(
$this->caches[self::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock])) {
            return
$this->caches[self::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock];
        }

       
$properties = [];
        foreach (\
preg_split('/;(?!base64|charset)/', $cssDeclarationsBlock) as $declaration) {
           
$matches = [];
            if (!\
preg_match('/^([A-Za-z\\-]+)\\s*:\\s*(.+)$/s', \trim($declaration), $matches)) {
                continue;
            }

           
$propertyName = \strtolower($matches[1]);
           
$propertyValue = $matches[2];
           
$properties[$propertyName] = $propertyValue;
        }
       
$this->caches[self::CACHE_KEY_CSS_DECLARATIONS_BLOCK][$cssDeclarationsBlock] = $properties;

        return
$properties;
    }

   
/**
     * Find the nodes that are not to be emogrified.
     *
     * @return \DOMElement[]
     *
     * @throws \InvalidArgumentException
     */
   
private function getNodesToExclude()
    {
       
$excludedNodes = [];
        foreach (\
array_keys($this->excludedSelectors) as $selectorToExclude) {
            try {
               
$matchingNodes = $this->xPath->query($this->translateCssToXpath($selectorToExclude));
            } catch (\
InvalidArgumentException $e) {
                if (
$this->debug) {
                    throw
$e;
                }
                continue;
            }
            foreach (
$matchingNodes as $node) {
               
$excludedNodes[] = $node;
            }
        }

        return
$excludedNodes;
    }

   
/**
     * Handles invalid xPath expression warnings, generated during the process() method,
     * during querying \DOMDocument and trigger an \InvalidArgumentException with an invalid selector
     * or \RuntimeException, depending on the source of the warning.
     *
     * @param int $type
     * @param string $message
     * @param string $file
     * @param int $line
     * @param array $context
     *
     * @return bool always false
     *
     * @throws \InvalidArgumentException
     * @throws \RuntimeException
     */
   
public function handleXpathQueryWarnings(// phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter
       
$type,
       
$message,
       
$file,
       
$line,
        array
$context
   
) {
       
$selector = '';
        if (isset(
$context['cssRule']['selector'])) {
           
// warnings generated by invalid/unrecognized selectors in method process()
           
$selector = $context['cssRule']['selector'];
        } elseif (isset(
$context['selectorToExclude'])) {
           
// warnings generated by invalid/unrecognized selectors in method getNodesToExclude()
           
$selector = $context['selectorToExclude'];
        } elseif (isset(
$context['cssSelector'])) {
           
// warnings generated by invalid/unrecognized selectors in method existsMatchForCssSelector()
           
$selector = $context['cssSelector'];
        }

        if (
$selector !== '') {
            throw new \
InvalidArgumentException(
                \
sprintf('%1$s in selector >> %2$s << in %3$s on line %4$u', $message, $selector, $file, $line),
               
1509279985
           
);
        }

       
// Catches eventual warnings generated by method getAllNodesWithStyleAttribute()
       
if (isset($context['xPath'])) {
            throw new \
RuntimeException(
                \
sprintf('%1$s in %2$s on line %3$u', $message, $file, $line),
               
1509280067
           
);
        }

       
// the normal error handling continues when handler return false
       
return false;
    }

   
/**
     * This is a rough attempt to mimic the behavior of handleXpathQueryWarnings in PHP 8 which
     * does not have the context argument that method depends on. This is most definitely not
     * entirely equivalent to the previous method.
     *
     * @param $type
     * @param $message
     * @param $file
     * @param $line
     */
   
public function handleXpathQueryWarningsPhp8(
       
$type,
       
$message,
       
$file,
       
$line
   
) {
       
$e = new \ErrorException($message, 0, $type, $file, $line);
       
$trace = $e->getTrace();

        for (
$i = 1; $i <= 2; $i++)
        {
            if (isset(
$trace[$i]))
            {
               
$errorFunction = $trace[$i]['function'] ?? '';

                switch (
$errorFunction)
                {
                    case
'process':
                    case
'getNodesToExclude':
                    case
'existsMatchForCssSelector':
                        throw new \
InvalidArgumentException(
                            \
sprintf('%1$s processing selector in %2$s on line %3$u', $message, $file, $line),
                           
1509279985
                       
);

                    case
'getAllNodesWithStyleAttribute':
                        throw new \
RuntimeException(
                            \
sprintf('%1$s in %2$s on line %3$u', $message, $file, $line),
                           
1509280067
                       
);
                }
            }
        }
    }

   
/**
     * Sets the debug mode.
     *
     * @param bool $debug set to true to enable debug mode
     *
     * @return void
     */
   
public function setDebug($debug)
    {
       
$this->debug = $debug;
    }
}