549 lines
19 KiB
PHP
549 lines
19 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 Apache-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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/** @var string Strip marker for comments. **/
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const PLACEHOLDER = "\x7fPLACEHOLDER\x7f";
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/**
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* Internet Explorer data URI length limit. See encodeImageAsDataURI().
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*/
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const DATA_URI_SIZE_LIMIT = 32768;
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const EMBED_REGEX = '\/\*\s*\@embed\s*\*\/';
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const COMMENT_REGEX = '\/\*.*?\*\/';
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/** @var string[] List of common image files extensions and MIME-types */
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protected static $mimeTypes = [
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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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'svg' => 'image/svg+xml',
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];
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/**
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* Get a list of local files referenced in a stylesheet (includes non-existent files).
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*
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* @param string $source CSS stylesheet source to process
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* @param string $path File path where the source was read from
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* @return string[] List of local file references
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*/
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public static function getLocalFileReferences( $source, $path ) {
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$stripped = preg_replace( '/' . self::COMMENT_REGEX . '/s', '', $source );
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$path = rtrim( $path, '/' ) . '/';
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$files = [];
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$rFlags = PREG_OFFSET_CAPTURE | PREG_SET_ORDER;
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if ( preg_match_all( '/' . self::getUrlRegex() . '/', $stripped, $matches, $rFlags ) ) {
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foreach ( $matches as $match ) {
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self::processUrlMatch( $match, $rFlags );
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$url = $match['file'][0];
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// Skip fully-qualified and protocol-relative URLs and data URIs
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if (
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substr( $url, 0, 2 ) === '//' ||
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parse_url( $url, PHP_URL_SCHEME )
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) {
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break;
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}
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// Strip trailing anchors - T115436
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$anchor = strpos( $url, '#' );
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if ( $anchor !== false ) {
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$url = substr( $url, 0, $anchor );
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// '#some-anchors' is not a file
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if ( $url === '' ) {
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break;
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}
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}
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$files[] = $path . $url;
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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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* Encode an image file as a data URI.
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*
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* If the image file has a suitable MIME type and size, encode it as a data URI, base64-encoded
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* for binary files or just percent-encoded otherwise. Return false if the image type is
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* unfamiliar or file exceeds the size limit.
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*
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* @param string $file Image file to encode.
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* @param string|null $type File's MIME type or null. If null, CSSMin will
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* try to autodetect the type.
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* @param bool $ie8Compat By default, a data URI will only be produced if it can be made short
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* enough to fit in Internet Explorer 8 (and earlier) URI length limit (32,768 bytes). Pass
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* `false` to remove this limitation.
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* @return string|false Image contents encoded as a data URI or false.
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*/
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public static function encodeImageAsDataURI( $file, $type = null, $ie8Compat = true ) {
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// Fast-fail for files that definitely exceed the maximum data URI length
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if ( $ie8Compat && filesize( $file ) >= self::DATA_URI_SIZE_LIMIT ) {
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return false;
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}
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if ( $type === null ) {
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$type = self::getMimeType( $file );
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}
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if ( !$type ) {
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return false;
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}
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return self::encodeStringAsDataURI( file_get_contents( $file ), $type, $ie8Compat );
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}
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/**
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* Encode file contents as a data URI with chosen MIME type.
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*
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* The URI will be base64-encoded for binary files or just percent-encoded otherwise.
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*
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* @since 1.25
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*
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* @param string $contents File contents to encode.
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* @param string $type File's MIME type.
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* @param bool $ie8Compat See encodeImageAsDataURI().
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* @return string|false Image contents encoded as a data URI or false.
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*/
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public static function encodeStringAsDataURI( $contents, $type, $ie8Compat = true ) {
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// Try #1: Non-encoded data URI
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// Remove XML declaration, it's not needed with data URI usage
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$contents = preg_replace( "/<\\?xml.*?\\?>/", '', $contents );
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// The regular expression matches ASCII whitespace and printable characters.
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if ( preg_match( '/^[\r\n\t\x20-\x7e]+$/', $contents ) ) {
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// Do not base64-encode non-binary files (sane SVGs).
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// (This often produces longer URLs, but they compress better, yielding a net smaller size.)
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$encoded = rawurlencode( $contents );
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// Unencode some things that don't need to be encoded, to make the encoding smaller
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$encoded = strtr( $encoded, [
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'%20' => ' ', // Unencode spaces
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'%2F' => '/', // Unencode slashes
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'%3A' => ':', // Unencode colons
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'%3D' => '=', // Unencode equals signs
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'%0A' => ' ', // Change newlines to spaces
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'%0D' => ' ', // Change carriage returns to spaces
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'%09' => ' ', // Change tabs to spaces
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] );
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// Consolidate runs of multiple spaces in a row
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$encoded = preg_replace( '/ {2,}/', ' ', $encoded );
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// Remove leading and trailing spaces
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$encoded = preg_replace( '/^ | $/', '', $encoded );
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$uri = 'data:' . $type . ',' . $encoded;
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if ( !$ie8Compat || strlen( $uri ) < self::DATA_URI_SIZE_LIMIT ) {
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return $uri;
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}
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}
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// Try #2: Encoded data URI
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$uri = 'data:' . $type . ';base64,' . base64_encode( $contents );
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if ( !$ie8Compat || strlen( $uri ) < self::DATA_URI_SIZE_LIMIT ) {
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return $uri;
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}
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// A data URI couldn't be produced
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return false;
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}
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/**
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* Serialize a string (escape and quote) for use as a CSS string value.
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* https://drafts.csswg.org/cssom/#serialize-a-string
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*
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* @param string $value
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* @return string
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*/
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public static function serializeStringValue( $value ) {
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$value = strtr( $value, [ "\0" => "\u{FFFD}", '\\' => '\\\\', '"' => '\\"' ] );
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$value = preg_replace_callback( '/[\x01-\x1f\x7f]/', function ( $match ) {
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return '\\' . base_convert( ord( $match[0] ), 10, 16 ) . ' ';
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}, $value );
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return '"' . $value . '"';
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}
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/**
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* @param string $file
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* @return bool|string
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*/
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public static function getMimeType( $file ) {
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// Infer the MIME-type from the file extension
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$ext = strtolower( pathinfo( $file, PATHINFO_EXTENSION ) );
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return self::$mimeTypes[$ext] ?? mime_content_type( realpath( $file ) );
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}
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/**
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* Build a CSS 'url()' value for the given URL, quoting parentheses (and other funny characters)
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* and escaping quotes as necessary.
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*
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* See http://www.w3.org/TR/css-syntax-3/#consume-a-url-token
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*
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* @param string $url URL to process
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* @return string 'url()' value, usually just `"url($url)"`, quoted/escaped if necessary
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*/
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public static function buildUrlValue( $url ) {
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// The list below has been crafted to match URLs such as:
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// scheme://user@domain:port/~user/fi%20le.png?query=yes&really=y+s
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// data:image/png;base64,R0lGODlh/+==
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if ( preg_match( '!^[\w\d:@/~.%+;,?&=-]+$!', $url ) ) {
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return "url($url)";
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} else {
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return 'url("' . strtr( $url, [ '\\' => '\\\\', '"' => '\\"' ] ) . '")';
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}
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}
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/**
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* Remaps CSS URL paths and automatically embeds data URIs for CSS rules
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* or url() values preceded by an / * @embed * / comment.
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*
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* @param string $source CSS data to remap
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* @param string $local File path where the source was read from
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* @param string $remote URL path to the file
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* @param bool $embedData If false, never do any data URI embedding,
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* 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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// High-level overview:
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// * For each CSS rule in $source that includes at least one url() value:
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// * Check for an @embed comment at the start indicating that all URIs should be embedded
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// * For each url() value:
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// * Check for an @embed comment directly preceding the value
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// * If either @embed comment exists:
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// * Embedding the URL as data: URI, if it's possible / allowed
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// * Otherwise remap the URL to work in generated stylesheets
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// Guard against trailing slashes, because "some/remote/../foo.png"
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// resolves to "some/remote/foo.png" on (some?) clients (T29052).
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if ( substr( $remote, -1 ) == '/' ) {
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$remote = substr( $remote, 0, -1 );
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}
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// Disallow U+007F DELETE, which is illegal anyway, and which
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// we use for comment placeholders.
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$source = str_replace( "\x7f", "?", $source );
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// Replace all comments by a placeholder so they will not interfere with the remapping.
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// Warning: This will also catch on anything looking like the start of a comment between
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// quotation marks (e.g. "foo /* bar").
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$comments = [];
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$pattern = '/(?!' . self::EMBED_REGEX . ')(' . self::COMMENT_REGEX . ')/s';
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$source = preg_replace_callback(
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$pattern,
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function ( $match ) use ( &$comments ) {
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$comments[] = $match[ 0 ];
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return CSSMin::PLACEHOLDER . ( count( $comments ) - 1 ) . 'x';
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},
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$source
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);
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// Note: This will not correctly handle cases where ';', '{' or '}'
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// appears in the rule itself, e.g. in a quoted string. You are advised
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// not to use such characters in file names. We also match start/end of
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// the string to be consistent in edge-cases ('@import url(…)').
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$pattern = '/(?:^|[;{])\K[^;{}]*' . self::getUrlRegex() . '[^;}]*(?=[;}]|$)/';
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$source = preg_replace_callback(
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$pattern,
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function ( $matchOuter ) use ( $local, $remote, $embedData ) {
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$rule = $matchOuter[0];
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// Check for global @embed comment and remove it. Allow other comments to be present
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// before @embed (they have been replaced with placeholders at this point).
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$embedAll = false;
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$rule = preg_replace(
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'/^((?:\s+|' .
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CSSMin::PLACEHOLDER .
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'(\d+)x)*)' .
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CSSMin::EMBED_REGEX .
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'\s*/',
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'$1',
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$rule,
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1,
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$embedAll
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);
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// Build two versions of current rule: with remapped URLs
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// and with embedded data: URIs (where possible).
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$pattern = '/(?P<embed>' . CSSMin::EMBED_REGEX . '\s*|)' . self::getUrlRegex() . '/';
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$ruleWithRemapped = preg_replace_callback(
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$pattern,
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function ( $match ) use ( $local, $remote ) {
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self::processUrlMatch( $match );
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$remapped = CSSMin::remapOne( $match['file'], $match['query'], $local, $remote, false );
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return CSSMin::buildUrlValue( $remapped );
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},
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$rule
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);
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if ( $embedData ) {
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// Remember the occurring MIME types to avoid fallbacks when embedding some files.
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$mimeTypes = [];
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$ruleWithEmbedded = preg_replace_callback(
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$pattern,
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function ( $match ) use ( $embedAll, $local, $remote, &$mimeTypes ) {
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self::processUrlMatch( $match );
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$embed = $embedAll || $match['embed'];
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$embedded = CSSMin::remapOne(
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$match['file'],
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$match['query'],
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$local,
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$remote,
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$embed
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);
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$url = $match['file'] . $match['query'];
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$file = "{$local}/{$match['file']}";
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if (
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!self::isRemoteUrl( $url ) && !self::isLocalUrl( $url )
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&& file_exists( $file )
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) {
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$mimeTypes[ CSSMin::getMimeType( $file ) ] = true;
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}
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return CSSMin::buildUrlValue( $embedded );
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},
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$rule
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);
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// Are all referenced images SVGs?
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$needsEmbedFallback = $mimeTypes !== [ 'image/svg+xml' => true ];
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}
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if ( !$embedData || $ruleWithEmbedded === $ruleWithRemapped ) {
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// We're not embedding anything, or we tried to but the file is not embeddable
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return $ruleWithRemapped;
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} elseif ( $embedData && $needsEmbedFallback ) {
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// Build 2 CSS properties; one which uses a data URI in place of the @embed comment, and
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// the other with a remapped and versioned URL with an Internet Explorer 6 and 7 hack
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// making it ignored in all browsers that support data URIs
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return "$ruleWithEmbedded;$ruleWithRemapped!ie";
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} else {
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// Look ma, no fallbacks! This is for files which IE 6 and 7 don't support anyway: SVG.
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return $ruleWithEmbedded;
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}
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}, $source );
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// Re-insert comments
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$pattern = '/' . self::PLACEHOLDER . '(\d+)x/';
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$source = preg_replace_callback( $pattern, function ( $match ) use ( &$comments ) {
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return $comments[ $match[1] ];
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}, $source );
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return $source;
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}
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/**
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* Is this CSS rule referencing a remote URL?
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*
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* @param string $maybeUrl
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* @return bool
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*/
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protected static function isRemoteUrl( $maybeUrl ) {
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if ( substr( $maybeUrl, 0, 2 ) === '//' || parse_url( $maybeUrl, PHP_URL_SCHEME ) ) {
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return true;
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}
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return false;
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}
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/**
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* Is this CSS rule referencing a local URL?
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*
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* @param string $maybeUrl
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* @return bool
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*/
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protected static function isLocalUrl( $maybeUrl ) {
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return isset( $maybeUrl[1] ) && $maybeUrl[0] === '/' && $maybeUrl[1] !== '/';
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}
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/**
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* @codeCoverageIgnore
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*/
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private static function getUrlRegex() {
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static $urlRegex;
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if ( $urlRegex === null ) {
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// Match these three variants separately to avoid broken urls when
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// e.g. a double quoted url contains a parenthesis, or when a
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// single quoted url contains a double quote, etc.
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// FIXME: Simplify now we only support PHP 7.0.0+
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// Note: PCRE doesn't support multiple capture groups with the same name by default.
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// - PCRE 6.7 introduced the "J" modifier (PCRE_INFO_JCHANGED for PCRE_DUPNAMES).
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// https://www.php.net/manual/en/reference.pcre.pattern.modifiers.php
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// However this isn't useful since it just ignores all but the first one.
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// Also, while the modifier was introduced in PCRE 6.7 (PHP 5.2+) it was
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// not exposed to public preg_* functions until PHP 5.6.0.
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// - PCRE 8.36 fixed this to work as expected (e.g. merge conceptually to
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// only return the one matched in the part that actually matched).
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// However MediaWiki supports 5.5.9, which has PCRE 8.32
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// Per https://www.php.net/manual/en/pcre.installation.php:
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// - PCRE 8.32 (PHP 5.5.0)
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// - PCRE 8.34 (PHP 5.5.10, PHP 5.6.0)
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// - PCRE 8.37 (PHP 5.5.26, PHP 5.6.9, PHP 7.0.0)
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// Workaround by using different groups and merge via processUrlMatch().
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// - Using string concatenation for class constant or member assignments
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// is only supported in PHP 5.6. Use a getter method for now.
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$urlRegex = '(' .
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// Unquoted url
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'url\(\s*(?P<file0>[^\s\'"][^\?\)]+?)(?P<query0>\?[^\)]*?|)\s*\)' .
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// Single quoted url
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'|url\(\s*\'(?P<file1>[^\?\']+?)(?P<query1>\?[^\']*?|)\'\s*\)' .
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// Double quoted url
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'|url\(\s*"(?P<file2>[^\?"]+?)(?P<query2>\?[^"]*?|)"\s*\)' .
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')';
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}
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return $urlRegex;
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}
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private static function processUrlMatch( array &$match, $flags = 0 ) {
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if ( $flags & PREG_SET_ORDER ) {
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// preg_match_all with PREG_SET_ORDER will return each group in each
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// match array, and if it didn't match, instead of the sub array
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// being an empty array it is `[ '', -1 ]`...
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if ( isset( $match['file0'] ) && $match['file0'][1] !== -1 ) {
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$match['file'] = $match['file0'];
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$match['query'] = $match['query0'];
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} elseif ( isset( $match['file1'] ) && $match['file1'][1] !== -1 ) {
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$match['file'] = $match['file1'];
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$match['query'] = $match['query1'];
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} else {
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if ( !isset( $match['file2'] ) || $match['file2'][1] === -1 ) {
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throw new Exception( 'URL must be non-empty' );
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}
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$match['file'] = $match['file2'];
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$match['query'] = $match['query2'];
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}
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} else {
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if ( isset( $match['file0'] ) && $match['file0'] !== '' ) {
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$match['file'] = $match['file0'];
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$match['query'] = $match['query0'];
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} elseif ( isset( $match['file1'] ) && $match['file1'] !== '' ) {
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$match['file'] = $match['file1'];
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$match['query'] = $match['query1'];
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} else {
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if ( !isset( $match['file2'] ) || $match['file2'] === '' ) {
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throw new Exception( 'URL must be non-empty' );
|
|
}
|
|
$match['file'] = $match['file2'];
|
|
$match['query'] = $match['query2'];
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Remap or embed a CSS URL path.
|
|
*
|
|
* @param string $file URL to remap/embed
|
|
* @param string $query
|
|
* @param string $local File path where the source was read from
|
|
* @param string $remote URL path to the file
|
|
* @param bool $embed Whether to do any data URI embedding
|
|
* @return string Remapped/embedded URL data
|
|
*/
|
|
public static function remapOne( $file, $query, $local, $remote, $embed ) {
|
|
// The full URL possibly with query, as passed to the 'url()' value in CSS
|
|
$url = $file . $query;
|
|
|
|
// Expand local URLs with absolute paths like /w/index.php to possibly protocol-relative URL, if
|
|
// wfExpandUrl() is available. (This will not be the case if we're running outside of MW.)
|
|
if ( self::isLocalUrl( $url ) && function_exists( 'wfExpandUrl' ) ) {
|
|
return wfExpandUrl( $url, PROTO_RELATIVE );
|
|
}
|
|
|
|
// Pass thru fully-qualified and protocol-relative URLs and data URIs, as well as local URLs if
|
|
// we can't expand them.
|
|
// Also skips anchors or the rare `behavior` property specifying application's default behavior
|
|
if (
|
|
self::isRemoteUrl( $url ) ||
|
|
self::isLocalUrl( $url ) ||
|
|
substr( $url, 0, 1 ) === '#'
|
|
) {
|
|
return $url;
|
|
}
|
|
|
|
if ( $local === false ) {
|
|
// Assume that all paths are relative to $remote, and make them absolute
|
|
$url = $remote . '/' . $url;
|
|
} else {
|
|
// We drop the query part here and instead make the path relative to $remote
|
|
$url = "{$remote}/{$file}";
|
|
// Path to the actual file on the filesystem
|
|
$localFile = "{$local}/{$file}";
|
|
if ( file_exists( $localFile ) ) {
|
|
if ( $embed ) {
|
|
$data = self::encodeImageAsDataURI( $localFile );
|
|
if ( $data !== false ) {
|
|
return $data;
|
|
}
|
|
}
|
|
if ( class_exists( OutputPage::class ) ) {
|
|
$url = OutputPage::transformFilePath( $remote, $local, $file );
|
|
} else {
|
|
// Add version parameter as the first five hex digits
|
|
// of the MD5 hash of the file's contents.
|
|
$url .= '?' . substr( md5_file( $localFile ), 0, 5 );
|
|
}
|
|
}
|
|
// If any of these conditions failed (file missing, we don't want to embed it
|
|
// or it's not embeddable), return the URL (possibly with ?timestamp part)
|
|
}
|
|
if ( function_exists( 'wfRemoveDotSegments' ) ) {
|
|
$url = wfRemoveDotSegments( $url );
|
|
}
|
|
return $url;
|
|
}
|
|
|
|
/**
|
|
* Removes whitespace from CSS data
|
|
*
|
|
* @param string $css CSS data to minify
|
|
* @return string Minified CSS data
|
|
*/
|
|
public static function minify( $css ) {
|
|
return trim(
|
|
str_replace(
|
|
[ '; ', ': ', ' {', '{ ', ', ', '} ', ';}', '( ', ' )', '[ ', ' ]' ],
|
|
[ ';', ':', '{', '{', ',', '}', '}', '(', ')', '[', ']' ],
|
|
preg_replace( [ '/\s+/', '/\/\*.*?\*\//s' ], [ ' ', '' ], $css )
|
|
)
|
|
);
|
|
}
|
|
}
|