DatabaseMysqlBase visibility cleanups
[mediawiki.git] / includes / libs / CSSMin.php
blob797a438d00ece6fce78f621b93d2aeed9cc42ec3
1 <?php
2 /**
3 * Minification of CSS stylesheets.
5 * Copyright 2010 Wikimedia Foundation
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software distributed
14 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
15 * OF ANY KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations under the License.
18 * @file
19 * @version 0.1.1 -- 2010-09-11
20 * @author Trevor Parscal <tparscal@wikimedia.org>
21 * @copyright Copyright 2010 Wikimedia Foundation
22 * @license http://www.apache.org/licenses/LICENSE-2.0
25 /**
26 * Transforms CSS data
28 * This class provides minification, URL remapping, URL extracting, and data-URL embedding.
30 class CSSMin {
32 /* Constants */
34 /** @var string Strip marker for comments. **/
35 const PLACEHOLDER = "\x7fPLACEHOLDER\x7f";
37 /**
38 * Internet Explorer data URI length limit. See encodeImageAsDataURI().
40 const DATA_URI_SIZE_LIMIT = 32768;
41 const URL_REGEX = 'url\(\s*[\'"]?(?P<file>[^\?\)\'"]*?)(?P<query>\?[^\)\'"]*?|)[\'"]?\s*\)';
42 const EMBED_REGEX = '\/\*\s*\@embed\s*\*\/';
43 const COMMENT_REGEX = '\/\*.*?\*\/';
45 /* Protected Static Members */
47 /** @var array List of common image files extensions and MIME-types */
48 protected static $mimeTypes = [
49 'gif' => 'image/gif',
50 'jpe' => 'image/jpeg',
51 'jpeg' => 'image/jpeg',
52 'jpg' => 'image/jpeg',
53 'png' => 'image/png',
54 'tif' => 'image/tiff',
55 'tiff' => 'image/tiff',
56 'xbm' => 'image/x-xbitmap',
57 'svg' => 'image/svg+xml',
60 /* Static Methods */
62 /**
63 * Get a list of local files referenced in a stylesheet (includes non-existent files).
65 * @param string $source CSS stylesheet source to process
66 * @param string $path File path where the source was read from
67 * @return array List of local file references
69 public static function getLocalFileReferences( $source, $path ) {
70 $stripped = preg_replace( '/' . self::COMMENT_REGEX . '/s', '', $source );
71 $path = rtrim( $path, '/' ) . '/';
72 $files = [];
74 $rFlags = PREG_OFFSET_CAPTURE | PREG_SET_ORDER;
75 if ( preg_match_all( '/' . self::URL_REGEX . '/', $stripped, $matches, $rFlags ) ) {
76 foreach ( $matches as $match ) {
77 $url = $match['file'][0];
79 // Skip fully-qualified and protocol-relative URLs and data URIs
80 if ( substr( $url, 0, 2 ) === '//' || parse_url( $url, PHP_URL_SCHEME ) ) {
81 break;
84 $files[] = $path . $url;
87 return $files;
90 /**
91 * Encode an image file as a data URI.
93 * If the image file has a suitable MIME type and size, encode it as a data URI, base64-encoded
94 * for binary files or just percent-encoded otherwise. Return false if the image type is
95 * unfamiliar or file exceeds the size limit.
97 * @param string $file Image file to encode.
98 * @param string|null $type File's MIME type or null. If null, CSSMin will
99 * try to autodetect the type.
100 * @param bool $ie8Compat By default, a data URI will only be produced if it can be made short
101 * enough to fit in Internet Explorer 8 (and earlier) URI length limit (32,768 bytes). Pass
102 * `false` to remove this limitation.
103 * @return string|bool Image contents encoded as a data URI or false.
105 public static function encodeImageAsDataURI( $file, $type = null, $ie8Compat = true ) {
106 // Fast-fail for files that definitely exceed the maximum data URI length
107 if ( $ie8Compat && filesize( $file ) >= self::DATA_URI_SIZE_LIMIT ) {
108 return false;
111 if ( $type === null ) {
112 $type = self::getMimeType( $file );
114 if ( !$type ) {
115 return false;
118 return self::encodeStringAsDataURI( file_get_contents( $file ), $type, $ie8Compat );
122 * Encode file contents as a data URI with chosen MIME type.
124 * The URI will be base64-encoded for binary files or just percent-encoded otherwise.
126 * @since 1.25
128 * @param string $contents File contents to encode.
129 * @param string $type File's MIME type.
130 * @param bool $ie8Compat See encodeImageAsDataURI().
131 * @return string|bool Image contents encoded as a data URI or false.
133 public static function encodeStringAsDataURI( $contents, $type, $ie8Compat = true ) {
134 // Try #1: Non-encoded data URI
135 // The regular expression matches ASCII whitespace and printable characters.
136 if ( preg_match( '/^[\r\n\t\x20-\x7e]+$/', $contents ) ) {
137 // Do not base64-encode non-binary files (sane SVGs).
138 // (This often produces longer URLs, but they compress better, yielding a net smaller size.)
139 $uri = 'data:' . $type . ',' . rawurlencode( $contents );
140 if ( !$ie8Compat || strlen( $uri ) < self::DATA_URI_SIZE_LIMIT ) {
141 return $uri;
145 // Try #2: Encoded data URI
146 $uri = 'data:' . $type . ';base64,' . base64_encode( $contents );
147 if ( !$ie8Compat || strlen( $uri ) < self::DATA_URI_SIZE_LIMIT ) {
148 return $uri;
151 // A data URI couldn't be produced
152 return false;
156 * Serialize a string (escape and quote) for use as a CSS string value.
157 * http://www.w3.org/TR/2013/WD-cssom-20131205/#serialize-a-string
159 * @param string $value
160 * @return string
161 * @throws Exception
163 public static function serializeStringValue( $value ) {
164 if ( strstr( $value, "\0" ) ) {
165 throw new Exception( "Invalid character in CSS string" );
167 $value = strtr( $value, [ '\\' => '\\\\', '"' => '\\"' ] );
168 $value = preg_replace_callback( '/[\x01-\x1f\x7f-\x9f]/', function ( $match ) {
169 return '\\' . base_convert( ord( $match[0] ), 10, 16 ) . ' ';
170 }, $value );
171 return '"' . $value . '"';
175 * @param string $file
176 * @return bool|string
178 public static function getMimeType( $file ) {
179 $realpath = realpath( $file );
180 if (
181 $realpath
182 && function_exists( 'finfo_file' )
183 && function_exists( 'finfo_open' )
184 && defined( 'FILEINFO_MIME_TYPE' )
186 return finfo_file( finfo_open( FILEINFO_MIME_TYPE ), $realpath );
189 // Infer the MIME-type from the file extension
190 $ext = strtolower( pathinfo( $file, PATHINFO_EXTENSION ) );
191 if ( isset( self::$mimeTypes[$ext] ) ) {
192 return self::$mimeTypes[$ext];
195 return false;
199 * Build a CSS 'url()' value for the given URL, quoting parentheses (and other funny characters)
200 * and escaping quotes as necessary.
202 * See http://www.w3.org/TR/css-syntax-3/#consume-a-url-token
204 * @param string $url URL to process
205 * @return string 'url()' value, usually just `"url($url)"`, quoted/escaped if necessary
207 public static function buildUrlValue( $url ) {
208 // The list below has been crafted to match URLs such as:
209 // scheme://user@domain:port/~user/fi%20le.png?query=yes&really=y+s
210 // data:image/png;base64,R0lGODlh/+==
211 if ( preg_match( '!^[\w\d:@/~.%+;,?&=-]+$!', $url ) ) {
212 return "url($url)";
213 } else {
214 return 'url("' . strtr( $url, [ '\\' => '\\\\', '"' => '\\"' ] ) . '")';
219 * Remaps CSS URL paths and automatically embeds data URIs for CSS rules
220 * or url() values preceded by an / * @embed * / comment.
222 * @param string $source CSS data to remap
223 * @param string $local File path where the source was read from
224 * @param string $remote URL path to the file
225 * @param bool $embedData If false, never do any data URI embedding,
226 * even if / * @embed * / is found.
227 * @return string Remapped CSS data
229 public static function remap( $source, $local, $remote, $embedData = true ) {
230 // High-level overview:
231 // * For each CSS rule in $source that includes at least one url() value:
232 // * Check for an @embed comment at the start indicating that all URIs should be embedded
233 // * For each url() value:
234 // * Check for an @embed comment directly preceding the value
235 // * If either @embed comment exists:
236 // * Embedding the URL as data: URI, if it's possible / allowed
237 // * Otherwise remap the URL to work in generated stylesheets
239 // Guard against trailing slashes, because "some/remote/../foo.png"
240 // resolves to "some/remote/foo.png" on (some?) clients (bug 27052).
241 if ( substr( $remote, -1 ) == '/' ) {
242 $remote = substr( $remote, 0, -1 );
245 // Disallow U+007F DELETE, which is illegal anyway, and which
246 // we use for comment placeholders.
247 $source = str_replace( "\x7f", "?", $source );
249 // Replace all comments by a placeholder so they will not interfere with the remapping.
250 // Warning: This will also catch on anything looking like the start of a comment between
251 // quotation marks (e.g. "foo /* bar").
252 $comments = [];
254 $pattern = '/(?!' . CSSMin::EMBED_REGEX . ')(' . CSSMin::COMMENT_REGEX . ')/s';
256 $source = preg_replace_callback(
257 $pattern,
258 function ( $match ) use ( &$comments ) {
259 $comments[] = $match[ 0 ];
260 return CSSMin::PLACEHOLDER . ( count( $comments ) - 1 ) . 'x';
262 $source
265 // Note: This will not correctly handle cases where ';', '{' or '}'
266 // appears in the rule itself, e.g. in a quoted string. You are advised
267 // not to use such characters in file names. We also match start/end of
268 // the string to be consistent in edge-cases ('@import url(…)').
269 $pattern = '/(?:^|[;{])\K[^;{}]*' . CSSMin::URL_REGEX . '[^;}]*(?=[;}]|$)/';
271 $source = preg_replace_callback(
272 $pattern,
273 function ( $matchOuter ) use ( $local, $remote, $embedData ) {
274 $rule = $matchOuter[0];
276 // Check for global @embed comment and remove it. Allow other comments to be present
277 // before @embed (they have been replaced with placeholders at this point).
278 $embedAll = false;
279 $rule = preg_replace(
280 '/^((?:\s+|' .
281 CSSMin::PLACEHOLDER .
282 '(\d+)x)*)' .
283 CSSMin::EMBED_REGEX .
284 '\s*/',
285 '$1',
286 $rule,
288 $embedAll
291 // Build two versions of current rule: with remapped URLs
292 // and with embedded data: URIs (where possible).
293 $pattern = '/(?P<embed>' . CSSMin::EMBED_REGEX . '\s*|)' . CSSMin::URL_REGEX . '/';
295 $ruleWithRemapped = preg_replace_callback(
296 $pattern,
297 function ( $match ) use ( $local, $remote ) {
298 $remapped = CSSMin::remapOne( $match['file'], $match['query'], $local, $remote, false );
300 return CSSMin::buildUrlValue( $remapped );
302 $rule
305 if ( $embedData ) {
306 // Remember the occurring MIME types to avoid fallbacks when embedding some files.
307 $mimeTypes = [];
309 $ruleWithEmbedded = preg_replace_callback(
310 $pattern,
311 function ( $match ) use ( $embedAll, $local, $remote, &$mimeTypes ) {
312 $embed = $embedAll || $match['embed'];
313 $embedded = CSSMin::remapOne(
314 $match['file'],
315 $match['query'],
316 $local,
317 $remote,
318 $embed
321 $url = $match['file'] . $match['query'];
322 $file = "{$local}/{$match['file']}";
323 if (
324 !self::isRemoteUrl( $url ) && !self::isLocalUrl( $url )
325 && file_exists( $file )
327 $mimeTypes[ CSSMin::getMimeType( $file ) ] = true;
330 return CSSMin::buildUrlValue( $embedded );
332 $rule
335 // Are all referenced images SVGs?
336 $needsEmbedFallback = $mimeTypes !== [ 'image/svg+xml' => true ];
339 if ( !$embedData || $ruleWithEmbedded === $ruleWithRemapped ) {
340 // We're not embedding anything, or we tried to but the file is not embeddable
341 return $ruleWithRemapped;
342 } elseif ( $embedData && $needsEmbedFallback ) {
343 // Build 2 CSS properties; one which uses a data URI in place of the @embed comment, and
344 // the other with a remapped and versioned URL with an Internet Explorer 6 and 7 hack
345 // making it ignored in all browsers that support data URIs
346 return "$ruleWithEmbedded;$ruleWithRemapped!ie";
347 } else {
348 // Look ma, no fallbacks! This is for files which IE 6 and 7 don't support anyway: SVG.
349 return $ruleWithEmbedded;
351 }, $source );
353 // Re-insert comments
354 $pattern = '/' . CSSMin::PLACEHOLDER . '(\d+)x/';
355 $source = preg_replace_callback( $pattern, function( $match ) use ( &$comments ) {
356 return $comments[ $match[1] ];
357 }, $source );
359 return $source;
364 * Is this CSS rule referencing a remote URL?
366 * @param string $maybeUrl
367 * @return bool
369 protected static function isRemoteUrl( $maybeUrl ) {
370 if ( substr( $maybeUrl, 0, 2 ) === '//' || parse_url( $maybeUrl, PHP_URL_SCHEME ) ) {
371 return true;
373 return false;
377 * Is this CSS rule referencing a local URL?
379 * @param string $maybeUrl
380 * @return bool
382 protected static function isLocalUrl( $maybeUrl ) {
383 if ( $maybeUrl !== '' && $maybeUrl[0] === '/' && !self::isRemoteUrl( $maybeUrl ) ) {
384 return true;
386 return false;
390 * Remap or embed a CSS URL path.
392 * @param string $file URL to remap/embed
393 * @param string $query
394 * @param string $local File path where the source was read from
395 * @param string $remote URL path to the file
396 * @param bool $embed Whether to do any data URI embedding
397 * @return string Remapped/embedded URL data
399 public static function remapOne( $file, $query, $local, $remote, $embed ) {
400 // The full URL possibly with query, as passed to the 'url()' value in CSS
401 $url = $file . $query;
403 // Expand local URLs with absolute paths like /w/index.php to possibly protocol-relative URL, if
404 // wfExpandUrl() is available. (This will not be the case if we're running outside of MW.)
405 if ( self::isLocalUrl( $url ) && function_exists( 'wfExpandUrl' ) ) {
406 return wfExpandUrl( $url, PROTO_RELATIVE );
409 // Pass thru fully-qualified and protocol-relative URLs and data URIs, as well as local URLs if
410 // we can't expand them.
411 if ( self::isRemoteUrl( $url ) || self::isLocalUrl( $url ) ) {
412 return $url;
415 if ( $local === false ) {
416 // Assume that all paths are relative to $remote, and make them absolute
417 $url = $remote . '/' . $url;
418 } else {
419 // We drop the query part here and instead make the path relative to $remote
420 $url = "{$remote}/{$file}";
421 // Path to the actual file on the filesystem
422 $localFile = "{$local}/{$file}";
423 if ( file_exists( $localFile ) ) {
424 if ( $embed ) {
425 $data = self::encodeImageAsDataURI( $localFile );
426 if ( $data !== false ) {
427 return $data;
430 if ( method_exists( 'OutputPage', 'transformFilePath' ) ) {
431 $url = OutputPage::transformFilePath( $remote, $local, $file );
432 } else {
433 // Add version parameter as the first five hex digits
434 // of the MD5 hash of the file's contents.
435 $url .= '?' . substr( md5_file( $localFile ), 0, 5 );
438 // If any of these conditions failed (file missing, we don't want to embed it
439 // or it's not embeddable), return the URL (possibly with ?timestamp part)
441 if ( function_exists( 'wfRemoveDotSegments' ) ) {
442 $url = wfRemoveDotSegments( $url );
444 return $url;
448 * Removes whitespace from CSS data
450 * @param string $css CSS data to minify
451 * @return string Minified CSS data
453 public static function minify( $css ) {
454 return trim(
455 str_replace(
456 [ '; ', ': ', ' {', '{ ', ', ', '} ', ';}' ],
457 [ ';', ':', '{', '{', ',', '}', '}' ],
458 preg_replace( [ '/\s+/', '/\/\*.*?\*\//s' ], [ ' ', '' ], $css )