laipower/wp-content/plugins/w3-total-cache/lib/YuiCssMin/Minifier.php

870 lines
26 KiB
PHP

<?php
namespace W3TCL\YuiCssMin;
/*!
* CssMin
* Author: Tubal Martin - http://tubalmartin.me/
* Repo: https://github.com/tubalmartin/YUI-CSS-compressor-PHP-port
*
* This is a PHP port of the CSS minification tool distributed with YUICompressor,
* itself a port of the cssmin utility by Isaac Schlueter - http://foohack.com/
* Permission is hereby granted to use the PHP version under the same
* conditions as the YUICompressor.
*/
/*!
* YUI Compressor
* http://developer.yahoo.com/yui/compressor/
* Author: Julien Lecomte - http://www.julienlecomte.net/
* Copyright (c) 2013 Yahoo! Inc. All rights reserved.
* The copyrights embodied in the content of this file are licensed
* by Yahoo! Inc. under the BSD (revised) open source license.
*/
class Minifier
{
const QUERY_FRACTION = '_CSSMIN_QF_';
const COMMENT_TOKEN = '_CSSMIN_CMT_%d_';
const COMMENT_TOKEN_START = '_CSSMIN_CMT_';
const RULE_BODY_TOKEN = '_CSSMIN_RBT_%d_';
const PRESERVED_TOKEN = '_CSSMIN_PTK_%d_';
// Token lists
private $comments = array();
private $ruleBodies = array();
private $preservedTokens = array();
// Output options
private $keepImportantComments = true;
private $keepSourceMapComment = false;
private $linebreakPosition = 0;
// PHP ini limits
private $raisePhpLimits;
private $memoryLimit;
private $maxExecutionTime = 60; // 1 min
private $pcreBacktrackLimit;
private $pcreRecursionLimit;
// Color maps
private $hexToNamedColorsMap;
private $namedToHexColorsMap;
// Regexes
private $numRegex;
private $charsetRegex = '/@charset [^;]+;/Si';
private $importRegex = '/@import [^;]+;/Si';
private $namespaceRegex = '/@namespace [^;]+;/Si';
private $namedToHexColorsRegex;
private $shortenOneZeroesRegex;
private $shortenTwoZeroesRegex;
private $shortenThreeZeroesRegex;
private $shortenFourZeroesRegex;
private $unitsGroupRegex = '(?:ch|cm|em|ex|gd|in|mm|px|pt|pc|q|rem|vh|vmax|vmin|vw|%)';
public static function minify_static($css, $options = array()) {
$m = new Minifier();
$css = \W3TCL\Minify\Minify_CSS_UriRewriter::rewrite($css, $options);
return $m->run($css);
}
/**
* @param bool|int $raisePhpLimits If true, PHP settings will be raised if needed
*/
public function __construct($raisePhpLimits = true)
{
$this->raisePhpLimits = (bool) $raisePhpLimits;
$this->memoryLimit = 128 * 1048576; // 128MB in bytes
$this->pcreBacktrackLimit = 1000 * 1000;
$this->pcreRecursionLimit = 500 * 1000;
$this->hexToNamedColorsMap = Colors::getHexToNamedMap();
$this->namedToHexColorsMap = Colors::getNamedToHexMap();
$this->namedToHexColorsRegex = sprintf(
'/([:,( ])(%s)( |,|\)|;|$)/Si',
implode('|', array_keys($this->namedToHexColorsMap))
);
$this->numRegex = sprintf('-?\d*\.?\d+%s?', $this->unitsGroupRegex);
$this->setShortenZeroValuesRegexes();
}
/**
* Parses & minifies the given input CSS string
* @param string $css
* @return string
*/
public function run($css = '')
{
if (empty($css) || !is_string($css)) {
return '';
}
$this->resetRunProperties();
if ($this->raisePhpLimits) {
$this->doRaisePhpLimits();
}
return $this->minify($css);
}
/**
* Sets whether to keep or remove sourcemap special comment.
* Sourcemap comments are removed by default.
* @param bool $keepSourceMapComment
*/
public function keepSourceMapComment($keepSourceMapComment = true)
{
$this->keepSourceMapComment = (bool) $keepSourceMapComment;
}
/**
* Sets whether to keep or remove important comments.
* Important comments outside of a declaration block are kept by default.
* @param bool $removeImportantComments
*/
public function removeImportantComments($removeImportantComments = true)
{
$this->keepImportantComments = !(bool) $removeImportantComments;
}
/**
* Sets the approximate column after which long lines will be splitted in the output
* with a linebreak.
* @param int $position
*/
public function setLineBreakPosition($position)
{
$this->linebreakPosition = (int) $position;
}
/**
* Sets the memory limit for this script
* @param int|string $limit
*/
public function setMemoryLimit($limit)
{
$this->memoryLimit = Utils::normalizeInt($limit);
}
/**
* Sets the maximum execution time for this script
* @param int|string $seconds
*/
public function setMaxExecutionTime($seconds)
{
$this->maxExecutionTime = (int) $seconds;
}
/**
* Sets the PCRE backtrack limit for this script
* @param int $limit
*/
public function setPcreBacktrackLimit($limit)
{
$this->pcreBacktrackLimit = (int) $limit;
}
/**
* Sets the PCRE recursion limit for this script
* @param int $limit
*/
public function setPcreRecursionLimit($limit)
{
$this->pcreRecursionLimit = (int) $limit;
}
/**
* Builds regular expressions needed for shortening zero values
*/
private function setShortenZeroValuesRegexes()
{
$zeroRegex = '0'. $this->unitsGroupRegex;
$numOrPosRegex = '('. $this->numRegex .'|top|left|bottom|right|center) ';
$oneZeroSafeProperties = array(
'(?:line-)?height',
'(?:(?:min|max)-)?width',
'top',
'left',
'background-position',
'bottom',
'right',
'border(?:-(?:top|left|bottom|right))?(?:-width)?',
'border-(?:(?:top|bottom)-(?:left|right)-)?radius',
'column-(?:gap|width)',
'margin(?:-(?:top|left|bottom|right))?',
'outline-width',
'padding(?:-(?:top|left|bottom|right))?'
);
// First zero regex
$regex = '/(^|;)('. implode('|', $oneZeroSafeProperties) .'):%s/Si';
$this->shortenOneZeroesRegex = sprintf($regex, $zeroRegex);
// Multiple zeroes regexes
$regex = '/(^|;)(margin|padding|border-(?:width|radius)|background-position):%s/Si';
$this->shortenTwoZeroesRegex = sprintf($regex, $numOrPosRegex . $zeroRegex);
$this->shortenThreeZeroesRegex = sprintf($regex, $numOrPosRegex . $numOrPosRegex . $zeroRegex);
$this->shortenFourZeroesRegex = sprintf($regex, $numOrPosRegex . $numOrPosRegex . $numOrPosRegex . $zeroRegex);
}
/**
* Resets properties whose value may change between runs
*/
private function resetRunProperties()
{
$this->comments = array();
$this->ruleBodies = array();
$this->preservedTokens = array();
}
/**
* Tries to configure PHP to use at least the suggested minimum settings
* @return void
*/
private function doRaisePhpLimits()
{
$phpLimits = array(
'memory_limit' => $this->memoryLimit,
'max_execution_time' => $this->maxExecutionTime,
'pcre.backtrack_limit' => $this->pcreBacktrackLimit,
'pcre.recursion_limit' => $this->pcreRecursionLimit
);
// If current settings are higher respect them.
foreach ($phpLimits as $name => $suggested) {
$current = Utils::normalizeInt(ini_get($name));
if ($current >= $suggested) {
continue;
}
// memoryLimit exception: allow -1 for "no memory limit".
if ($name === 'memory_limit' && $current === -1) {
continue;
}
// maxExecutionTime exception: allow 0 for "no memory limit".
if ($name === 'max_execution_time' && $current === 0) {
continue;
}
ini_set($name, $suggested);
}
}
/**
* Registers a preserved token
* @param string $token
* @return string The token ID string
*/
private function registerPreservedToken($token)
{
$tokenId = sprintf(self::PRESERVED_TOKEN, count($this->preservedTokens));
$this->preservedTokens[$tokenId] = $token;
return $tokenId;
}
/**
* Registers a candidate comment token
* @param string $comment
* @return string The comment token ID string
*/
private function registerCommentToken($comment)
{
$tokenId = sprintf(self::COMMENT_TOKEN, count($this->comments));
$this->comments[$tokenId] = $comment;
return $tokenId;
}
/**
* Registers a rule body token
* @param string $body the minified rule body
* @return string The rule body token ID string
*/
private function registerRuleBodyToken($body)
{
if (empty($body)) {
return '';
}
$tokenId = sprintf(self::RULE_BODY_TOKEN, count($this->ruleBodies));
$this->ruleBodies[$tokenId] = $body;
return $tokenId;
}
/**
* Parses & minifies the given input CSS string
* @param string $css
* @return string
*/
private function minify($css)
{
// Process data urls
$css = $this->processDataUrls($css);
// Process comments
$css = preg_replace_callback(
'/(?<!\\\\)\/\*(.*?)\*(?<!\\\\)\//Ss',
array($this, 'processCommentsCallback'),
$css
);
// IE7: Process Microsoft matrix filters (whitespaces between Matrix parameters). Can contain strings inside.
$css = preg_replace_callback(
'/filter:\s*progid:DXImageTransform\.Microsoft\.Matrix\(([^)]+)\)/Ss',
array($this, 'processOldIeSpecificMatrixDefinitionCallback'),
$css
);
// Process quoted unquotable attribute selectors to unquote them. Covers most common cases.
// Likelyhood of a quoted attribute selector being a substring in a string: Very very low.
$css = preg_replace(
'/\[\s*([a-z][a-z-]+)\s*([\*\|\^\$~]?=)\s*[\'"](-?[a-z_][a-z0-9-_]+)[\'"]\s*\]/Ssi',
'[$1$2$3]',
$css
);
// Process strings so their content doesn't get accidentally minified
$css = preg_replace_callback(
'/(?:"(?:[^\\\\"]|\\\\.|\\\\)*")|'."(?:'(?:[^\\\\']|\\\\.|\\\\)*')/S",
array($this, 'processStringsCallback'),
$css
);
// Normalize all whitespace strings to single spaces. Easier to work with that way.
$css = preg_replace('/\s+/S', ' ', $css);
// Process comments
$css = $this->processComments($css);
// Process rule bodies
$css = $this->processRuleBodies($css);
// Process at-rules and selectors
$css = $this->processAtRulesAndSelectors($css);
// Restore preserved rule bodies before splitting
$css = strtr($css, $this->ruleBodies);
// Some source control tools don't like it when files containing lines longer
// than, say 8000 characters, are checked in. The linebreak option is used in
// that case to split long lines after a specific column.
if ($this->linebreakPosition > 0) {
$l = strlen($css);
$offset = $this->linebreakPosition;
while (preg_match('/(?<!\\\\)\}(?!\n)/S', $css, $matches, PREG_OFFSET_CAPTURE, $offset)) {
$matchIndex = $matches[0][1];
$css = substr_replace($css, "\n", $matchIndex + 1, 0);
$offset = $matchIndex + 2 + $this->linebreakPosition;
$l += 1;
if ($offset > $l) {
break;
}
}
}
// Restore preserved comments and strings
$css = strtr($css, $this->preservedTokens);
return trim($css);
}
/**
* Searches & replaces all data urls with tokens before we start compressing,
* to avoid performance issues running some of the subsequent regexes against large string chunks.
* @param string $css
* @return string
*/
private function processDataUrls($css)
{
$ret = '';
$searchOffset = $substrOffset = 0;
// Since we need to account for non-base64 data urls, we need to handle
// ' and ) being part of the data string.
while (preg_match('/url\(\s*(["\']?)data:/Si', $css, $m, PREG_OFFSET_CAPTURE, $searchOffset)) {
$matchStartIndex = $m[0][1];
$dataStartIndex = $matchStartIndex + 4; // url( length
$searchOffset = $matchStartIndex + strlen($m[0][0]);
$terminator = $m[1][0]; // ', " or empty (not quoted)
$terminatorRegex = '/(?<!\\\\)'. (strlen($terminator) === 0 ? '' : $terminator.'\s*') .'(\))/S';
$ret .= substr($css, $substrOffset, $matchStartIndex - $substrOffset);
// Terminator found
if (preg_match($terminatorRegex, $css, $matches, PREG_OFFSET_CAPTURE, $searchOffset)) {
$matchEndIndex = $matches[1][1];
$searchOffset = $matchEndIndex + 1;
$token = substr($css, $dataStartIndex, $matchEndIndex - $dataStartIndex);
// Remove all spaces only for base64 encoded URLs.
if (stripos($token, 'base64,') !== false) {
$token = preg_replace('/\s+/S', '', $token);
}
$ret .= 'url('. $this->registerPreservedToken(trim($token)) .')';
// No end terminator found, re-add the whole match. Should we throw/warn here?
} else {
$ret .= substr($css, $matchStartIndex, $searchOffset - $matchStartIndex);
}
$substrOffset = $searchOffset;
}
$ret .= substr($css, $substrOffset);
return $ret;
}
/**
* Registers all comments found as candidates to be preserved.
* @param array $matches
* @return string
*/
private function processCommentsCallback($matches)
{
return '/*'. $this->registerCommentToken($matches[1]) .'*/';
}
/**
* Preserves old IE Matrix string definition
* @param array $matches
* @return string
*/
private function processOldIeSpecificMatrixDefinitionCallback($matches)
{
return 'filter:progid:DXImageTransform.Microsoft.Matrix('. $this->registerPreservedToken($matches[1]) .')';
}
/**
* Preserves strings found
* @param array $matches
* @return string
*/
private function processStringsCallback($matches)
{
$match = $matches[0];
$quote = substr($match, 0, 1);
$match = substr($match, 1, -1);
// maybe the string contains a comment-like substring?
// one, maybe more? put'em back then
if (strpos($match, self::COMMENT_TOKEN_START) !== false) {
$match = strtr($match, $this->comments);
}
// minify alpha opacity in filter strings
$match = str_ireplace('progid:DXImageTransform.Microsoft.Alpha(Opacity=', 'alpha(opacity=', $match);
return $quote . $this->registerPreservedToken($match) . $quote;
}
/**
* Preserves or removes comments found.
* @param string $css
* @return string
*/
private function processComments($css)
{
foreach ($this->comments as $commentId => $comment) {
$commentIdString = '/*'. $commentId .'*/';
// ! in the first position of the comment means preserve
// so push to the preserved tokens keeping the !
if ($this->keepImportantComments && strpos($comment, '!') === 0) {
$preservedTokenId = $this->registerPreservedToken($comment);
// Put new lines before and after /*! important comments
$css = str_replace($commentIdString, "\n/*$preservedTokenId*/\n", $css);
continue;
}
// # sourceMappingURL= in the first position of the comment means sourcemap
// so push to the preserved tokens if {$this->keepSourceMapComment} is truthy.
if ($this->keepSourceMapComment && strpos($comment, '# sourceMappingURL=') === 0) {
$preservedTokenId = $this->registerPreservedToken($comment);
// Add new line before the sourcemap comment
$css = str_replace($commentIdString, "\n/*$preservedTokenId*/", $css);
continue;
}
// Keep empty comments after child selectors (IE7 hack)
// e.g. html >/**/ body
if (strlen($comment) === 0 && strpos($css, '>/*'.$commentId) !== false) {
$css = str_replace($commentId, $this->registerPreservedToken(''), $css);
continue;
}
// in all other cases kill the comment
$css = str_replace($commentIdString, '', $css);
}
// Normalize whitespace again
$css = preg_replace('/ +/S', ' ', $css);
return $css;
}
/**
* Finds, minifies & preserves all rule bodies.
* @param string $css the whole stylesheet.
* @return string
*/
private function processRuleBodies($css)
{
$ret = '';
$searchOffset = $substrOffset = 0;
while (($blockStartPos = strpos($css, '{', $searchOffset)) !== false) {
$blockEndPos = strpos($css, '}', $blockStartPos);
$nextBlockStartPos = strpos($css, '{', $blockStartPos + 1);
$ret .= substr($css, $substrOffset, $blockStartPos - $substrOffset);
if ($nextBlockStartPos !== false && $nextBlockStartPos < $blockEndPos) {
$ret .= substr($css, $blockStartPos, $nextBlockStartPos - $blockStartPos);
$searchOffset = $nextBlockStartPos;
} else {
$ruleBody = substr($css, $blockStartPos + 1, $blockEndPos - $blockStartPos - 1);
$ruleBodyToken = $this->registerRuleBodyToken($this->processRuleBody($ruleBody));
$ret .= '{'. $ruleBodyToken .'}';
$searchOffset = $blockEndPos + 1;
}
$substrOffset = $searchOffset;
}
$ret .= substr($css, $substrOffset);
return $ret;
}
/**
* Compresses non-group rule bodies.
* @param string $body The rule body without curly braces
* @return string
*/
private function processRuleBody($body)
{
$body = trim($body);
// Remove spaces before the things that should not have spaces before them.
$body = preg_replace('/ ([:=,)*\/;\n])/S', '$1', $body);
// Remove the spaces after the things that should not have spaces after them.
$body = preg_replace('/([:=,(*\/!;\n]) /S', '$1', $body);
// Replace multiple semi-colons in a row by a single one
$body = preg_replace('/;;+/S', ';', $body);
// Remove semicolon before closing brace except when:
// - The last property is prefixed with a `*` (lte IE7 hack) to avoid issues on Symbian S60 3.x browsers.
if (!preg_match('/\*[a-z0-9-]+:[^;]+;$/Si', $body)) {
$body = rtrim($body, ';');
}
// Remove important comments inside a rule body (because they make no sense here).
if (strpos($body, '/*') !== false) {
$body = preg_replace('/\n?\/\*[A-Z0-9_]+\*\/\n?/S', '', $body);
}
// Empty rule body? Exit :)
if (empty($body)) {
return '';
}
// Shorten font-weight values
$body = preg_replace(
array('/(font-weight:)bold\b/Si', '/(font-weight:)normal\b/Si'),
array('${1}700', '${1}400'),
$body
);
// Shorten background property
$body = preg_replace('/(background:)(?:none|transparent)( !|;|$)/Si', '${1}0 0$2', $body);
// Shorten opacity IE filter
$body = str_ireplace('progid:DXImageTransform.Microsoft.Alpha(Opacity=', 'alpha(opacity=', $body);
// Shorten colors from rgb(51,102,153) to #336699, rgb(100%,0%,0%) to #ff0000 (sRGB color space)
// Shorten colors from hsl(0, 100%, 50%) to #ff0000 (sRGB color space)
// This makes it more likely that it'll get further compressed in the next step.
$body = preg_replace_callback(
'/(rgb|hsl)\(([0-9,.% -]+)\)(.|$)/Si',
array($this, 'shortenHslAndRgbToHexCallback'),
$body
);
// Shorten colors from #AABBCC to #ABC or shorter color name:
// - Look for hex colors which don't have a "=" in front of them (to avoid MSIE filters)
$body = preg_replace_callback(
'/(?<!=)#([0-9a-f]{3,6})( |,|\)|;|$)/Si',
array($this, 'shortenHexColorsCallback'),
$body
);
// Shorten long named colors with a shorter HEX counterpart: white -> #fff.
// Run at least 2 times to cover most cases
$body = preg_replace_callback(
array($this->namedToHexColorsRegex, $this->namedToHexColorsRegex),
array($this, 'shortenNamedColorsCallback'),
$body
);
// Replace positive sign from numbers before the leading space is removed.
// +1.2em to 1.2em, +.8px to .8px, +2% to 2%
$body = preg_replace('/([ :,(])\+(\.?\d+)/S', '$1$2', $body);
// shorten ms to s
$body = preg_replace_callback('/([ :,(])(-?)(\d{3,})ms/Si', function ($matches) {
return $matches[1] . $matches[2] . ((int) $matches[3] / 1000) .'s';
}, $body);
// Remove leading zeros from integer and float numbers.
// 000.6 to .6, -0.8 to -.8, 0050 to 50, -01.05 to -1.05
$body = preg_replace('/([ :,(])(-?)0+([1-9]?\.?\d+)/S', '$1$2$3', $body);
// Remove trailing zeros from float numbers.
// -6.0100em to -6.01em, .0100 to .01, 1.200px to 1.2px
$body = preg_replace('/([ :,(])(-?\d?\.\d+?)0+([^\d])/S', '$1$2$3', $body);
// Remove trailing .0 -> -9.0 to -9
$body = preg_replace('/([ :,(])(-?\d+)\.0([^\d])/S', '$1$2$3', $body);
// Replace 0 length numbers with 0
$body = preg_replace('/([ :,(])-?\.?0+([^\d])/S', '${1}0$2', $body);
// Shorten zero values for safe properties only
$body = preg_replace(
array(
$this->shortenOneZeroesRegex,
$this->shortenTwoZeroesRegex,
$this->shortenThreeZeroesRegex,
$this->shortenFourZeroesRegex
),
array(
'$1$2:0',
'$1$2:$3 0',
'$1$2:$3 $4 0',
'$1$2:$3 $4 $5 0'
),
$body
);
// Replace 0 0 0; or 0 0 0 0; with 0 0 for background-position property.
$body = preg_replace('/(background-position):0(?: 0){2,3}( !|;|$)/Si', '$1:0 0$2', $body);
// Shorten suitable shorthand properties with repeated values
$body = preg_replace(
array(
'/(margin|padding|border-(?:width|radius)):('.$this->numRegex.')(?: \2)+( !|;|$)/Si',
'/(border-(?:style|color)):([#a-z0-9]+)(?: \2)+( !|;|$)/Si'
),
'$1:$2$3',
$body
);
$body = preg_replace(
array(
'/(margin|padding|border-(?:width|radius)):'.
'('.$this->numRegex.') ('.$this->numRegex.') \2 \3( !|;|$)/Si',
'/(border-(?:style|color)):([#a-z0-9]+) ([#a-z0-9]+) \2 \3( !|;|$)/Si'
),
'$1:$2 $3$4',
$body
);
$body = preg_replace(
array(
'/(margin|padding|border-(?:width|radius)):'.
'('.$this->numRegex.') ('.$this->numRegex.') ('.$this->numRegex.') \3( !|;|$)/Si',
'/(border-(?:style|color)):([#a-z0-9]+) ([#a-z0-9]+) ([#a-z0-9]+) \3( !|;|$)/Si'
),
'$1:$2 $3 $4$5',
$body
);
// Lowercase some common functions that can be values
$body = preg_replace_callback(
'/(?:attr|blur|brightness|circle|contrast|cubic-bezier|drop-shadow|ellipse|from|grayscale|'.
'hsla?|hue-rotate|inset|invert|local|minmax|opacity|perspective|polygon|rgba?|rect|repeat|saturate|sepia|'.
'steps|to|url|var|-webkit-gradient|'.
'(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?(?:calc|(?:repeating-)?(?:linear|radial)-gradient))\(/Si',
array($this, 'strtolowerCallback'),
$body
);
// Lowercase all uppercase properties
$body = preg_replace_callback('/(?:^|;)[A-Z-]+:/S', array($this, 'strtolowerCallback'), $body);
return $body;
}
/**
* Compresses At-rules and selectors.
* @param string $css the whole stylesheet with rule bodies tokenized.
* @return string
*/
private function processAtRulesAndSelectors($css)
{
$charset = '';
$imports = '';
$namespaces = '';
// Remove spaces before the things that should not have spaces before them.
$css = preg_replace('/ ([@{};>+)\]~=,\/\n])/S', '$1', $css);
// Remove the spaces after the things that should not have spaces after them.
$css = preg_replace('/([{}:;>+(\[~=,\/\n]) /S', '$1', $css);
// Shorten shortable double colon (CSS3) pseudo-elements to single colon (CSS2)
$css = preg_replace('/::(before|after|first-(?:line|letter))(\{|,)/Si', ':$1$2', $css);
// Retain space for special IE6 cases
$css = preg_replace_callback('/:first-(line|letter)(\{|,)/Si', function ($matches) {
return ':first-'. strtolower($matches[1]) .' '. $matches[2];
}, $css);
// Find a fraction that may used in some @media queries such as: (min-aspect-ratio: 1/1)
// Add token to add the "/" back in later
$css = preg_replace('/\(([a-z-]+):([0-9]+)\/([0-9]+)\)/Si', '($1:$2'. self::QUERY_FRACTION .'$3)', $css);
// Remove empty rule blocks up to 2 levels deep.
$css = preg_replace(array_fill(0, 2, '/(\{)[^{};\/\n]+\{\}/S'), '$1', $css);
$css = preg_replace('/[^{};\/\n]+\{\}/S', '', $css);
// Two important comments next to each other? Remove extra newline.
if ($this->keepImportantComments) {
$css = str_replace("\n\n", "\n", $css);
}
// Restore fraction
$css = str_replace(self::QUERY_FRACTION, '/', $css);
// Lowercase some popular @directives
$css = preg_replace_callback(
'/(?<!\\\\)@(?:charset|document|font-face|import|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?keyframes|media|'.
'namespace|page|supports|viewport)/Si',
array($this, 'strtolowerCallback'),
$css
);
// Lowercase some popular media types
$css = preg_replace_callback(
'/[ ,](?:all|aural|braille|handheld|print|projection|screen|tty|tv|embossed|speech)[ ,;{]/Si',
array($this, 'strtolowerCallback'),
$css
);
// Lowercase some common pseudo-classes & pseudo-elements
$css = preg_replace_callback(
'/(?<!\\\\):(?:active|after|before|checked|default|disabled|empty|enabled|first-(?:child|of-type)|'.
'focus(?:-within)?|hover|indeterminate|in-range|invalid|lang\(|last-(?:child|of-type)|left|link|not\(|'.
'nth-(?:child|of-type)\(|nth-last-(?:child|of-type)\(|only-(?:child|of-type)|optional|out-of-range|'.
'read-(?:only|write)|required|right|root|:selection|target|valid|visited)/Si',
array($this, 'strtolowerCallback'),
$css
);
// @charset handling
if (preg_match($this->charsetRegex, $css, $matches)) {
// Keep the first @charset at-rule found
$charset = $matches[0];
// Delete all @charset at-rules
$css = preg_replace($this->charsetRegex, '', $css);
}
// @import handling
$css = preg_replace_callback($this->importRegex, function ($matches) use (&$imports) {
// Keep all @import at-rules found for later
$imports .= $matches[0];
// Delete all @import at-rules
return '';
}, $css);
// @namespace handling
$css = preg_replace_callback($this->namespaceRegex, function ($matches) use (&$namespaces) {
// Keep all @namespace at-rules found for later
$namespaces .= $matches[0];
// Delete all @namespace at-rules
return '';
}, $css);
// Order critical at-rules:
// 1. @charset first
// 2. @imports below @charset
// 3. @namespaces below @imports
$css = $charset . $imports . $namespaces . $css;
return $css;
}
/**
* Converts hsl() & rgb() colors to HEX format.
* @param $matches
* @return string
*/
private function shortenHslAndRgbToHexCallback($matches)
{
$type = $matches[1];
$values = explode(',', $matches[2]);
$terminator = $matches[3];
if ($type === 'hsl') {
$values = Utils::hslToRgb($values);
}
$hexColors = Utils::rgbToHex($values);
// Restore space after rgb() or hsl() function in some cases such as:
// background-image: linear-gradient(to bottom, rgb(210,180,140) 10%, rgb(255,0,0) 90%);
if (!empty($terminator) && !preg_match('/[ ,);]/S', $terminator)) {
$terminator = ' '. $terminator;
}
return '#'. implode('', $hexColors) . $terminator;
}
/**
* Compresses HEX color values of the form #AABBCC to #ABC or short color name.
* @param $matches
* @return string
*/
private function shortenHexColorsCallback($matches)
{
$hex = $matches[1];
// Shorten suitable 6 chars HEX colors
if (strlen($hex) === 6 && preg_match('/^([0-9a-f])\1([0-9a-f])\2([0-9a-f])\3$/Si', $hex, $m)) {
$hex = $m[1] . $m[2] . $m[3];
}
// Lowercase
$hex = '#'. strtolower($hex);
// Replace Hex colors with shorter color names
$color = array_key_exists($hex, $this->hexToNamedColorsMap) ? $this->hexToNamedColorsMap[$hex] : $hex;
return $color . $matches[2];
}
/**
* Shortens all named colors with a shorter HEX counterpart for a set of safe properties
* e.g. white -> #fff
* @param array $matches
* @return string
*/
private function shortenNamedColorsCallback($matches)
{
return $matches[1] . $this->namedToHexColorsMap[strtolower($matches[2])] . $matches[3];
}
/**
* Makes a string lowercase
* @param array $matches
* @return string
*/
private function strtolowerCallback($matches)
{
return strtolower($matches[0]);
}
}