229 lines
8.1 KiB
PHP
229 lines
8.1 KiB
PHP
<?php
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/**
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* Minification of CSS stylesheets.
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*
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* Copyright 2010 Wikimedia Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software distributed
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* under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
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* OF ANY KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations under the License.
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*
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* @file
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* @version 0.1.1 -- 2010-09-11
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* @author Trevor Parscal <tparscal@wikimedia.org>
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* @copyright Copyright 2010 Wikimedia Foundation
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* @license http://www.apache.org/licenses/LICENSE-2.0
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*/
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/**
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* Transforms CSS data
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*
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* This class provides minification, URL remapping, URL extracting, and data-URL embedding.
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*/
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class CSSMin {
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/* Constants */
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/**
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* Maximum file size to still qualify for in-line embedding as a data-URI
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*
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* 24,576 is used because Internet Explorer has a 32,768 byte limit for data URIs,
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* which when base64 encoded will result in a 1/3 increase in size.
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*/
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const EMBED_SIZE_LIMIT = 24576;
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const URL_REGEX = 'url\(\s*[\'"]?(?P<file>[^\?\)\'"]*)(?P<query>\??[^\)\'"]*)[\'"]?\s*\)';
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/* Protected Static Members */
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/** @var array List of common image files extensions and mime-types */
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protected static $mimeTypes = array(
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'gif' => 'image/gif',
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'jpe' => 'image/jpeg',
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'jpeg' => 'image/jpeg',
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'jpg' => 'image/jpeg',
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'png' => 'image/png',
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'tif' => 'image/tiff',
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'tiff' => 'image/tiff',
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'xbm' => 'image/x-xbitmap',
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);
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/* Static Methods */
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/**
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* Gets a list of local file paths which are referenced in a CSS style sheet
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*
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* @param $source string CSS data to remap
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* @param $path string File path where the source was read from (optional)
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* @return array List of local file references
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*/
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public static function getLocalFileReferences( $source, $path = null ) {
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$files = array();
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$rFlags = PREG_OFFSET_CAPTURE | PREG_SET_ORDER;
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if ( preg_match_all( '/' . self::URL_REGEX . '/', $source, $matches, $rFlags ) ) {
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foreach ( $matches as $match ) {
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$file = ( isset( $path )
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? rtrim( $path, '/' ) . '/'
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: '' ) . "{$match['file'][0]}";
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// Only proceed if we can access the file
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if ( !is_null( $path ) && file_exists( $file ) ) {
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$files[] = $file;
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}
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}
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}
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return $files;
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}
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/**
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* @param $file string
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* @return bool|string
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*/
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protected static function getMimeType( $file ) {
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$realpath = realpath( $file );
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// Try a couple of different ways to get the mime-type of a file, in order of
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// preference
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if (
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$realpath
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&& function_exists( 'finfo_file' )
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&& function_exists( 'finfo_open' )
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&& defined( 'FILEINFO_MIME_TYPE' )
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) {
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// As of PHP 5.3, this is how you get the mime-type of a file; it uses the Fileinfo
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// PECL extension
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return finfo_file( finfo_open( FILEINFO_MIME_TYPE ), $realpath );
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} elseif ( function_exists( 'mime_content_type' ) ) {
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// Before this was deprecated in PHP 5.3, this was how you got the mime-type of a file
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return mime_content_type( $file );
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} else {
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// Worst-case scenario has happened, use the file extension to infer the mime-type
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$ext = strtolower( pathinfo( $file, PATHINFO_EXTENSION ) );
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if ( isset( self::$mimeTypes[$ext] ) ) {
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return self::$mimeTypes[$ext];
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}
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}
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return false;
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}
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/**
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* Remaps CSS URL paths and automatically embeds data URIs for URL rules
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* preceded by an /* @embed * / comment
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*
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* @param $source string CSS data to remap
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* @param $local string File path where the source was read from
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* @param $remote string URL path to the file
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* @param $embedData bool If false, never do any data URI embedding, even if / * @embed * / is found
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* @return string Remapped CSS data
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*/
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public static function remap( $source, $local, $remote, $embedData = true ) {
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$pattern = '/((?P<embed>\s*\/\*\s*\@embed\s*\*\/)(?P<pre>[^\;\}]*))?' .
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self::URL_REGEX . '(?P<post>[^;]*)[\;]?/';
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$offset = 0;
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while ( preg_match( $pattern, $source, $match, PREG_OFFSET_CAPTURE, $offset ) ) {
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// Skip fully-qualified URLs and data URIs
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$urlScheme = parse_url( $match['file'][0], PHP_URL_SCHEME );
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if ( $urlScheme ) {
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// Move the offset to the end of the match, leaving it alone
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$offset = $match[0][1] + strlen( $match[0][0] );
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continue;
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}
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// URLs with absolute paths like /w/index.php need to be expanded
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// to absolute URLs but otherwise left alone
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if ( $match['file'][0] !== '' && $match['file'][0][0] === '/' ) {
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// Replace the file path with an expanded (possibly protocol-relative) URL
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// ...but only if wfExpandUrl() is even available.
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// This will not be the case if we're running outside of MW
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$lengthIncrease = 0;
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if ( function_exists( 'wfExpandUrl' ) ) {
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$expanded = wfExpandUrl( $match['file'][0], PROTO_RELATIVE );
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$origLength = strlen( $match['file'][0] );
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$lengthIncrease = strlen( $expanded ) - $origLength;
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$source = substr_replace( $source, $expanded,
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$match['file'][1], $origLength
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);
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}
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// Move the offset to the end of the match, leaving it alone
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$offset = $match[0][1] + strlen( $match[0][0] ) + $lengthIncrease;
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continue;
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}
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// Shortcuts
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$embed = $match['embed'][0];
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$pre = $match['pre'][0];
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$post = $match['post'][0];
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$query = $match['query'][0];
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$url = "{$remote}/{$match['file'][0]}";
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$file = "{$local}/{$match['file'][0]}";
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// bug 27052 - Guard against double slashes, because foo//../bar
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// apparently resolves to foo/bar on (some?) clients
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$url = preg_replace( '#([^:])//+#', '\1/', $url );
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$replacement = false;
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if ( $local !== false && file_exists( $file ) ) {
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// Add version parameter as a time-stamp in ISO 8601 format,
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// using Z for the timezone, meaning GMT
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$url .= '?' . gmdate( 'Y-m-d\TH:i:s\Z', round( filemtime( $file ), -2 ) );
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// Embedding requires a bit of extra processing, so let's skip that if we can
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if ( $embedData && $embed ) {
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$type = self::getMimeType( $file );
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// Detect when URLs were preceeded with embed tags, and also verify file size is
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// below the limit
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if (
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$type
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&& $match['embed'][1] > 0
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&& filesize( $file ) < self::EMBED_SIZE_LIMIT
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) {
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// Strip off any trailing = symbols (makes browsers freak out)
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$data = base64_encode( file_get_contents( $file ) );
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// Build 2 CSS properties; one which uses a base64 encoded data URI in place
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// of the @embed comment to try and retain line-number integrity, and the
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// other with a remapped an versioned URL and an Internet Explorer hack
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// making it ignored in all browsers that support data URIs
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$replacement = "{$pre}url(data:{$type};base64,{$data}){$post};";
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$replacement .= "{$pre}url({$url}){$post}!ie;";
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}
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}
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if ( $replacement === false ) {
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// Assume that all paths are relative to $remote, and make them absolute
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$replacement = "{$embed}{$pre}url({$url}){$post};";
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}
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} elseif ( $local === false ) {
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// Assume that all paths are relative to $remote, and make them absolute
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$replacement = "{$embed}{$pre}url({$url}{$query}){$post};";
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}
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if ( $replacement !== false ) {
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// Perform replacement on the source
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$source = substr_replace(
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$source, $replacement, $match[0][1], strlen( $match[0][0] )
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);
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// Move the offset to the end of the replacement in the source
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$offset = $match[0][1] + strlen( $replacement );
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continue;
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}
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// Move the offset to the end of the match, leaving it alone
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$offset = $match[0][1] + strlen( $match[0][0] );
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}
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return $source;
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}
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/**
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* Removes whitespace from CSS data
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*
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* @param $css string CSS data to minify
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* @return string Minified CSS data
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*/
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public static function minify( $css ) {
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return trim(
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str_replace(
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array( '; ', ': ', ' {', '{ ', ', ', '} ', ';}' ),
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array( ';', ':', '{', '{', ',', '}', '}' ),
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preg_replace( array( '/\s+/', '/\/\*.*?\*\//s' ), array( ' ', '' ), $css )
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)
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);
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}
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}
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