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See Release Notes
Long Term Support Release

  • Bug fixes for general core bugs in 4.1.x will end 13 November 2023 (12 months).
  • Bug fixes for security issues in 4.1.x will end 10 November 2025 (36 months).
  • PHP version: minimum PHP 7.4.0 Note: minimum PHP version has increased since Moodle 4.0. PHP 8.0.x is supported too.
<?php
/**
 * CSS Minifier
 *
 * Please report bugs on https://github.com/matthiasmullie/minify/issues
 *
 * @author Matthias Mullie <minify@mullie.eu>
 * @copyright Copyright (c) 2012, Matthias Mullie. All rights reserved
 * @license MIT License
 */

namespace MatthiasMullie\Minify;

use MatthiasMullie\Minify\Exceptions\FileImportException;
use MatthiasMullie\PathConverter\ConverterInterface;
use MatthiasMullie\PathConverter\Converter;

/**
 * CSS minifier
 *
 * Please report bugs on https://github.com/matthiasmullie/minify/issues
 *
 * @package Minify
 * @author Matthias Mullie <minify@mullie.eu>
 * @author Tijs Verkoyen <minify@verkoyen.eu>
 * @copyright Copyright (c) 2012, Matthias Mullie. All rights reserved
 * @license MIT License
 */
class CSS extends Minify
{
    /**
     * @var int maximum inport size in kB
     */
    protected $maxImportSize = 5;

    /**
     * @var string[] valid import extensions
     */
    protected $importExtensions = array(
        'gif' => 'data:image/gif',
        'png' => 'data:image/png',
        'jpe' => 'data:image/jpeg',
        'jpg' => 'data:image/jpeg',
        'jpeg' => 'data:image/jpeg',
        'svg' => 'data:image/svg+xml',
        'woff' => 'data:application/x-font-woff',
> 'woff2' => 'data:application/x-font-woff2', 'tif' => 'image/tiff', > 'avif' => 'data:image/avif', 'tiff' => 'image/tiff', > 'apng' => 'data:image/apng', 'xbm' => 'image/x-xbitmap', > 'webp' => 'data:image/webp',
); /** * Set the maximum size if files to be imported. * * Files larger than this size (in kB) will not be imported into the CSS. * Importing files into the CSS as data-uri will save you some connections, * but we should only import relatively small decorative images so that our * CSS file doesn't get too bulky. * * @param int $size Size in kB */ public function setMaxImportSize($size) { $this->maxImportSize = $size; } /** * Set the type of extensions to be imported into the CSS (to save network * connections). * Keys of the array should be the file extensions & respective values * should be the data type. * * @param string[] $extensions Array of file extensions */ public function setImportExtensions(array $extensions) { $this->importExtensions = $extensions; } /** * Move any import statements to the top. * * @param string $content Nearly finished CSS content * * @return string */ protected function moveImportsToTop($content) { if (preg_match_all('/(;?)(@import (?<url>url\()?(?P<quotes>["\']?).+?(?P=quotes)(?(url)\)));?/', $content, $matches)) { // remove from content foreach ($matches[0] as $import) { $content = str_replace($import, '', $content); } // add to top $content = implode(';', $matches[2]).';'.trim($content, ';'); } return $content; } /** * Combine CSS from import statements. * * @import's will be loaded and their content merged into the original file, * to save HTTP requests. * * @param string $source The file to combine imports for * @param string $content The CSS content to combine imports for * @param string[] $parents Parent paths, for circular reference checks * * @return string * * @throws FileImportException */ protected function combineImports($source, $content, $parents) { $importRegexes = array( // @import url(xxx) '/ # import statement @import # whitespace \s+ # open url() url\( # (optional) open path enclosure (?P<quotes>["\']?) # fetch path (?P<path>.+?) # (optional) close path enclosure (?P=quotes) # close url() \) # (optional) trailing whitespace \s* # (optional) media statement(s) (?P<media>[^;]*) # (optional) trailing whitespace \s* # (optional) closing semi-colon ;? /ix', // @import 'xxx' '/ # import statement @import # whitespace \s+ # open path enclosure (?P<quotes>["\']) # fetch path (?P<path>.+?) # close path enclosure (?P=quotes) # (optional) trailing whitespace \s* # (optional) media statement(s) (?P<media>[^;]*) # (optional) trailing whitespace \s* # (optional) closing semi-colon ;? /ix', ); // find all relative imports in css $matches = array(); foreach ($importRegexes as $importRegex) { if (preg_match_all($importRegex, $content, $regexMatches, PREG_SET_ORDER)) { $matches = array_merge($matches, $regexMatches); } } $search = array(); $replace = array(); // loop the matches foreach ($matches as $match) { // get the path for the file that will be imported $importPath = dirname($source).'/'.$match['path']; // only replace the import with the content if we can grab the // content of the file if (!$this->canImportByPath($match['path']) || !$this->canImportFile($importPath)) { continue; } // check if current file was not imported previously in the same // import chain. if (in_array($importPath, $parents)) { throw new FileImportException('Failed to import file "'.$importPath.'": circular reference detected.'); } // grab referenced file & minify it (which may include importing // yet other @import statements recursively) $minifier = new self($importPath); $minifier->setMaxImportSize($this->maxImportSize); $minifier->setImportExtensions($this->importExtensions); $importContent = $minifier->execute($source, $parents); // check if this is only valid for certain media if (!empty($match['media'])) { $importContent = '@media '.$match['media'].'{'.$importContent.'}'; } // add to replacement array $search[] = $match[0]; $replace[] = $importContent; } // replace the import statements return str_replace($search, $replace, $content); } /** * Import files into the CSS, base64-ized. * * @url(image.jpg) images will be loaded and their content merged into the * original file, to save HTTP requests. * * @param string $source The file to import files for * @param string $content The CSS content to import files for * * @return string */ protected function importFiles($source, $content) { $regex = '/url\((["\']?)(.+?)\\1\)/i'; if ($this->importExtensions && preg_match_all($regex, $content, $matches, PREG_SET_ORDER)) { $search = array(); $replace = array(); // loop the matches foreach ($matches as $match) { $extension = substr(strrchr($match[2], '.'), 1); if ($extension && !array_key_exists($extension, $this->importExtensions)) { continue; } // get the path for the file that will be imported $path = $match[2]; $path = dirname($source).'/'.$path; // only replace the import with the content if we're able to get // the content of the file, and it's relatively small if ($this->canImportFile($path) && $this->canImportBySize($path)) { // grab content && base64-ize $importContent = $this->load($path); $importContent = base64_encode($importContent); // build replacement $search[] = $match[0]; $replace[] = 'url('.$this->importExtensions[$extension].';base64,'.$importContent.')'; } } // replace the import statements $content = str_replace($search, $replace, $content); } return $content; } /** * Minify the data. * Perform CSS optimizations. * * @param string[optional] $path Path to write the data to * @param string[] $parents Parent paths, for circular reference checks * * @return string The minified data */ public function execute($path = null, $parents = array()) { $content = ''; // loop CSS data (raw data and files) foreach ($this->data as $source => $css) { /* * Let's first take out strings & comments, since we can't just * remove whitespace anywhere. If whitespace occurs inside a string, * we should leave it alone. E.g.: * p { content: "a test" } */ $this->extractStrings(); $this->stripComments(); $this->extractMath(); $this->extractCustomProperties(); $css = $this->replace($css); $css = $this->stripWhitespace($css); $css = $this->shortenColors($css); $css = $this->shortenZeroes($css); $css = $this->shortenFontWeights($css); $css = $this->stripEmptyTags($css); // restore the string we've extracted earlier $css = $this->restoreExtractedData($css); $source = is_int($source) ? '' : $source; $parents = $source ? array_merge($parents, array($source)) : $parents; $css = $this->combineImports($source, $css, $parents); $css = $this->importFiles($source, $css); /* * If we'll save to a new path, we'll have to fix the relative paths * to be relative no longer to the source file, but to the new path. * If we don't write to a file, fall back to same path so no * conversion happens (because we still want it to go through most * of the move code, which also addresses url() & @import syntax...) */ $converter = $this->getPathConverter($source, $path ?: $source); $css = $this->move($converter, $css); // combine css $content .= $css; } $content = $this->moveImportsToTop($content); return $content; } /** * Moving a css file should update all relative urls. * Relative references (e.g. ../images/image.gif) in a certain css file, * will have to be updated when a file is being saved at another location * (e.g. ../../images/image.gif, if the new CSS file is 1 folder deeper). * * @param ConverterInterface $converter Relative path converter * @param string $content The CSS content to update relative urls for * * @return string */ protected function move(ConverterInterface $converter, $content) { /* * Relative path references will usually be enclosed by url(). @import * is an exception, where url() is not necessary around the path (but is * allowed). * This *could* be 1 regular expression, where both regular expressions * in this array are on different sides of a |. But we're using named * patterns in both regexes, the same name on both regexes. This is only * possible with a (?J) modifier, but that only works after a fairly * recent PCRE version. That's why I'm doing 2 separate regular * expressions & combining the matches after executing of both. */ $relativeRegexes = array( // url(xxx) '/ # open url() url\( \s* # open path enclosure (?P<quotes>["\'])? # fetch path (?P<path>.+?) # close path enclosure (?(quotes)(?P=quotes)) \s* # close url() \) /ix', // @import "xxx" '/ # import statement @import # whitespace \s+ # we don\'t have to check for @import url(), because the # condition above will already catch these # open path enclosure (?P<quotes>["\']) # fetch path (?P<path>.+?) # close path enclosure (?P=quotes) /ix', ); // find all relative urls in css $matches = array(); foreach ($relativeRegexes as $relativeRegex) { if (preg_match_all($relativeRegex, $content, $regexMatches, PREG_SET_ORDER)) { $matches = array_merge($matches, $regexMatches); } } $search = array(); $replace = array(); // loop all urls foreach ($matches as $match) { // determine if it's a url() or an @import match $type = (strpos($match[0], '@import') === 0 ? 'import' : 'url'); $url = $match['path']; if ($this->canImportByPath($url)) { // attempting to interpret GET-params makes no sense, so let's discard them for awhile $params = strrchr($url, '?'); $url = $params ? substr($url, 0, -strlen($params)) : $url; // fix relative url $url = $converter->convert($url); // now that the path has been converted, re-apply GET-params $url .= $params; } /* * Urls with control characters above 0x7e should be quoted. * According to Mozilla's parser, whitespace is only allowed at the * end of unquoted urls. * Urls with `)` (as could happen with data: uris) should also be * quoted to avoid being confused for the url() closing parentheses. * And urls with a # have also been reported to cause issues. * Urls with quotes inside should also remain escaped. * * @see https://developer.mozilla.org/nl/docs/Web/CSS/url#The_url()_functional_notation * @see https://hg.mozilla.org/mozilla-central/rev/14abca4e7378 * @see https://github.com/matthiasmullie/minify/issues/193 */ $url = trim($url); if (preg_match('/[\s\)\'"#\x{7f}-\x{9f}]/u', $url)) { $url = $match['quotes'] . $url . $match['quotes']; } // build replacement $search[] = $match[0]; if ($type === 'url') { $replace[] = 'url('.$url.')'; } elseif ($type === 'import') { $replace[] = '@import "'.$url.'"'; } } // replace urls return str_replace($search, $replace, $content); } /** * Shorthand hex color codes. * #FF0000 -> #F00. * * @param string $content The CSS content to shorten the hex color codes for * * @return string */ protected function shortenColors($content) { $content = preg_replace('/(?<=[: ])#([0-9a-z])\\1([0-9a-z])\\2([0-9a-z])\\3(?:([0-9a-z])\\4)?(?=[; }])/i', '#$1$2$3$4', $content); // remove alpha channel if it's pointless... $content = preg_replace('/(?<=[: ])#([0-9a-z]{6})ff?(?=[; }])/i', '#$1', $content); $content = preg_replace('/(?<=[: ])#([0-9a-z]{3})f?(?=[; }])/i', '#$1', $content); $colors = array( // we can shorten some even more by replacing them with their color name '#F0FFFF' => 'azure', '#F5F5DC' => 'beige', '#A52A2A' => 'brown', '#FF7F50' => 'coral', '#FFD700' => 'gold', '#808080' => 'gray', '#008000' => 'green', '#4B0082' => 'indigo', '#FFFFF0' => 'ivory', '#F0E68C' => 'khaki', '#FAF0E6' => 'linen', '#800000' => 'maroon', '#000080' => 'navy', '#808000' => 'olive', '#CD853F' => 'peru', '#FFC0CB' => 'pink', '#DDA0DD' => 'plum', '#800080' => 'purple', '#F00' => 'red', '#FA8072' => 'salmon', '#A0522D' => 'sienna', '#C0C0C0' => 'silver', '#FFFAFA' => 'snow', '#D2B48C' => 'tan', '#FF6347' => 'tomato', '#EE82EE' => 'violet', '#F5DEB3' => 'wheat', // or the other way around 'WHITE' => '#fff', 'BLACK' => '#000', ); return preg_replace_callback( '/(?<=[: ])('.implode('|', array_keys($colors)).')(?=[; }])/i', function ($match) use ($colors) { return $colors[strtoupper($match[0])]; }, $content ); } /** * Shorten CSS font weights. * * @param string $content The CSS content to shorten the font weights for * * @return string */ protected function shortenFontWeights($content) { $weights = array( 'normal' => 400, 'bold' => 700, ); $callback = function ($match) use ($weights) { return $match[1].$weights[$match[2]]; }; return preg_replace_callback('/(font-weight\s*:\s*)('.implode('|', array_keys($weights)).')(?=[;}])/', $callback, $content); } /** * Shorthand 0 values to plain 0, instead of e.g. -0em. * * @param string $content The CSS content to shorten the zero values for * * @return string */ protected function shortenZeroes($content) { // we don't want to strip units in `calc()` expressions: // `5px - 0px` is valid, but `5px - 0` is not // `10px * 0` is valid (equates to 0), and so is `10 * 0px`, but // `10 * 0` is invalid // we've extracted calcs earlier, so we don't need to worry about this // reusable bits of code throughout these regexes: // before & after are used to make sure we don't match lose unintended // 0-like values (e.g. in #000, or in http://url/1.0) // units can be stripped from 0 values, or used to recognize non 0 // values (where wa may be able to strip a .0 suffix) $before = '(?<=[:(, ])'; $after = '(?=[ ,);}])'; $units = '(em|ex|%|px|cm|mm|in|pt|pc|ch|rem|vh|vw|vmin|vmax|vm)'; // strip units after zeroes (0px -> 0) // NOTE: it should be safe to remove all units for a 0 value, but in // practice, Webkit (especially Safari) seems to stumble over at least // 0%, potentially other units as well. Only stripping 'px' for now. // @see https://github.com/matthiasmullie/minify/issues/60 $content = preg_replace('/'.$before.'(-?0*(\.0+)?)(?<=0)px'.$after.'/', '\\1', $content); // strip 0-digits (.0 -> 0) $content = preg_replace('/'.$before.'\.0+'.$units.'?'.$after.'/', '0\\1', $content); // strip trailing 0: 50.10 -> 50.1, 50.10px -> 50.1px $content = preg_replace('/'.$before.'(-?[0-9]+\.[0-9]+)0+'.$units.'?'.$after.'/', '\\1\\2', $content); // strip trailing 0: 50.00 -> 50, 50.00px -> 50px $content = preg_replace('/'.$before.'(-?[0-9]+)\.0+'.$units.'?'.$after.'/', '\\1\\2', $content); // strip leading 0: 0.1 -> .1, 01.1 -> 1.1 $content = preg_replace('/'.$before.'(-?)0+([0-9]*\.[0-9]+)'.$units.'?'.$after.'/', '\\1\\2\\3', $content); // strip negative zeroes (-0 -> 0) & truncate zeroes (00 -> 0) $content = preg_replace('/'.$before.'-?0+'.$units.'?'.$after.'/', '0\\1', $content); // IE doesn't seem to understand a unitless flex-basis value (correct - // it goes against the spec), so let's add it in again (make it `%`, // which is only 1 char: 0%, 0px, 0 anything, it's all just the same) // @see https://developer.mozilla.org/nl/docs/Web/CSS/flex $content = preg_replace('/flex:([0-9]+\s[0-9]+\s)0([;\}])/', 'flex:${1}0%${2}', $content); $content = preg_replace('/flex-basis:0([;\}])/', 'flex-basis:0%${1}', $content); return $content; } /** * Strip empty tags from source code. * * @param string $content * * @return string */ protected function stripEmptyTags($content) { $content = preg_replace('/(?<=^)[^\{\};]+\{\s*\}/', '', $content); $content = preg_replace('/(?<=(\}|;))[^\{\};]+\{\s*\}/', '', $content); return $content; } /** * Strip comments from source code. */ protected function stripComments() { // PHP only supports $this inside anonymous functions since 5.4 $minifier = $this; $callback = function ($match) use ($minifier) { $count = count($minifier->extracted); $placeholder = '/*'.$count.'*/'; $minifier->extracted[$placeholder] = $match[0]; return $placeholder; }; // Moodle-specific change MDL-68191 starts. /* This was the old code: $this->registerPattern('/\n?\/\*(!|.*?@license|.*?@preserve).*?\*\/\n?/s', $callback); */ // This is the new, more accurate and faster regex. $this->registerPattern('/ # optional newline \n? # start comment \/\* # comment content (?: # either starts with an ! ! | # or, after some number of characters which do not end the comment (?:(?!\*\/).)*? # there is either a @license or @preserve tag @(?:license|preserve) ) # then match to the end of the comment .*?\*\/\n? /ixs', $callback); // Moodle-specific change MDL-68191. $this->registerPattern('/\/\*.*?\*\//s', ''); } /** * Strip whitespace. * * @param string $content The CSS content to strip the whitespace for * * @return string */ protected function stripWhitespace($content) { // remove leading & trailing whitespace $content = preg_replace('/^\s*/m', '', $content); $content = preg_replace('/\s*$/m', '', $content); // replace newlines with a single space $content = preg_replace('/\s+/', ' ', $content); // remove whitespace around meta characters // inspired by stackoverflow.com/questions/15195750/minify-compress-css-with-regex $content = preg_replace('/\s*([\*$~^|]?+=|[{};,>~]|!important\b)\s*/', '$1', $content); $content = preg_replace('/([\[(:>\+])\s+/', '$1', $content); $content = preg_replace('/\s+([\]\)>\+])/', '$1', $content); $content = preg_replace('/\s+(:)(?![^\}]*\{)/', '$1', $content); // whitespace around + and - can only be stripped inside some pseudo- // classes, like `:nth-child(3+2n)` // not in things like `calc(3px + 2px)`, shorthands like `3px -2px`, or // selectors like `div.weird- p` $pseudos = array('nth-child', 'nth-last-child', 'nth-last-of-type', 'nth-of-type'); $content = preg_replace('/:('.implode('|', $pseudos).')\(\s*([+-]?)\s*(.+?)\s*([+-]?)\s*(.*?)\s*\)/', ':$1($2$3$4$5)', $content); // remove semicolon/whitespace followed by closing bracket $content = str_replace(';}', '}', $content); return trim($content); } /** * Replace all occurrences of functions that may contain math, where * whitespace around operators needs to be preserved (e.g. calc, clamp) */ protected function extractMath() { $functions = array('calc', 'clamp', 'min', 'max'); $pattern = '/\b('. implode('|', $functions) .')(\(.+?)(?=$|;|})/m'; // PHP only supports $this inside anonymous functions since 5.4 $minifier = $this; $callback = function ($match) use ($minifier, $pattern, &$callback) { $function = $match[1]; $length = strlen($match[2]); $expr = ''; $opened = 0; // the regular expression for extracting math has 1 significant problem: // it can't determine the correct closing parenthesis... // instead, it'll match a larger portion of code to where it's certain that // the calc() musts have ended, and we'll figure out which is the correct // closing parenthesis here, by counting how many have opened for ($i = 0; $i < $length; $i++) { $char = $match[2][$i]; $expr .= $char; if ($char === '(') { $opened++; } elseif ($char === ')' && --$opened === 0) { break; } } // now that we've figured out where the calc() starts and ends, extract it $count = count($minifier->extracted); $placeholder = 'math('.$count.')'; $minifier->extracted[$placeholder] = $function.'('.trim(substr($expr, 1, -1)).')'; // and since we've captured more code than required, we may have some leftover // calc() in here too - go recursive on the remaining but of code to go figure // that out and extract what is needed
< $rest = str_replace($function.$expr, '', $match[0]);
> $rest = $minifier->str_replace_first($function.$expr, '', $match[0]);
$rest = preg_replace_callback($pattern, $callback, $rest); return $placeholder.$rest; }; $this->registerPattern($pattern, $callback); } /** * Replace custom properties, whose values may be used in scenarios where * we wouldn't want them to be minified (e.g. inside calc) */ protected function extractCustomProperties() { // PHP only supports $this inside anonymous functions since 5.4 $minifier = $this; $this->registerPattern(
< '/(?<=^|[;}])(--[^:;{}"\'\s]+)\s*:([^;{}]+)/m',
> > '/(?<=^|[;}{])\s*(--[^:;{}"\'\s]+)\s*:([^;{}]+)/m',
function ($match) use ($minifier) { $placeholder = '--custom-'. count($minifier->extracted) . ':0'; $minifier->extracted[$placeholder] = $match[1] .':'. trim($match[2]); return $placeholder; } ); } /** * Check if file is small enough to be imported. * * @param string $path The path to the file * * @return bool */ protected function canImportBySize($path) { return ($size = @filesize($path)) && $size <= $this->maxImportSize * 1024; } /** * Check if file a file can be imported, going by the path. * * @param string $path * * @return bool */ protected function canImportByPath($path) { return preg_match('/^(data:|https?:|\\/)/', $path) === 0; } /** * Return a converter to update relative paths to be relative to the new * destination. * * @param string $source * @param string $target * * @return ConverterInterface */ protected function getPathConverter($source, $target) { return new Converter($source, $target); } }