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597 daniel-mar 1
<?php
1042 daniel-mar 2
 
597 daniel-mar 3
/**
1042 daniel-mar 4
 * CSS Minifier.
597 daniel-mar 5
 *
6
 * Please report bugs on https://github.com/matthiasmullie/minify/issues
7
 *
8
 * @author Matthias Mullie <minify@mullie.eu>
9
 * @copyright Copyright (c) 2012, Matthias Mullie. All rights reserved
10
 * @license MIT License
11
 */
12
 
13
namespace MatthiasMullie\Minify;
14
 
15
use MatthiasMullie\Minify\Exceptions\FileImportException;
1042 daniel-mar 16
use MatthiasMullie\PathConverter\Converter;
597 daniel-mar 17
use MatthiasMullie\PathConverter\ConverterInterface;
18
 
19
/**
1042 daniel-mar 20
 * CSS minifier.
597 daniel-mar 21
 *
22
 * Please report bugs on https://github.com/matthiasmullie/minify/issues
23
 *
24
 * @author Matthias Mullie <minify@mullie.eu>
25
 * @author Tijs Verkoyen <minify@verkoyen.eu>
26
 * @copyright Copyright (c) 2012, Matthias Mullie. All rights reserved
27
 * @license MIT License
28
 */
29
class CSS extends Minify
30
{
31
    /**
32
     * @var int maximum inport size in kB
33
     */
34
    protected $maxImportSize = 5;
35
 
36
    /**
37
     * @var string[] valid import extensions
38
     */
39
    protected $importExtensions = array(
40
        'gif' => 'data:image/gif',
41
        'png' => 'data:image/png',
42
        'jpe' => 'data:image/jpeg',
43
        'jpg' => 'data:image/jpeg',
44
        'jpeg' => 'data:image/jpeg',
45
        'svg' => 'data:image/svg+xml',
46
        'woff' => 'data:application/x-font-woff',
842 daniel-mar 47
        'woff2' => 'data:application/x-font-woff2',
48
        'avif' => 'data:image/avif',
49
        'apng' => 'data:image/apng',
50
        'webp' => 'data:image/webp',
597 daniel-mar 51
        'tif' => 'image/tiff',
52
        'tiff' => 'image/tiff',
53
        'xbm' => 'image/x-xbitmap',
54
    );
55
 
56
    /**
57
     * Set the maximum size if files to be imported.
58
     *
59
     * Files larger than this size (in kB) will not be imported into the CSS.
60
     * Importing files into the CSS as data-uri will save you some connections,
61
     * but we should only import relatively small decorative images so that our
62
     * CSS file doesn't get too bulky.
63
     *
64
     * @param int $size Size in kB
65
     */
66
    public function setMaxImportSize($size)
67
    {
68
        $this->maxImportSize = $size;
69
    }
70
 
71
    /**
72
     * Set the type of extensions to be imported into the CSS (to save network
73
     * connections).
74
     * Keys of the array should be the file extensions & respective values
75
     * should be the data type.
76
     *
77
     * @param string[] $extensions Array of file extensions
78
     */
79
    public function setImportExtensions(array $extensions)
80
    {
81
        $this->importExtensions = $extensions;
82
    }
83
 
84
    /**
85
     * Move any import statements to the top.
86
     *
87
     * @param string $content Nearly finished CSS content
88
     *
89
     * @return string
90
     */
91
    protected function moveImportsToTop($content)
92
    {
93
        if (preg_match_all('/(;?)(@import (?<url>url\()?(?P<quotes>["\']?).+?(?P=quotes)(?(url)\)));?/', $content, $matches)) {
94
            // remove from content
95
            foreach ($matches[0] as $import) {
96
                $content = str_replace($import, '', $content);
97
            }
98
 
99
            // add to top
1042 daniel-mar 100
            $content = implode(';', $matches[2]) . ';' . trim($content, ';');
597 daniel-mar 101
        }
102
 
103
        return $content;
104
    }
105
 
106
    /**
107
     * Combine CSS from import statements.
108
     *
1469 daniel-mar 109
     * \@import's will be loaded and their content merged into the original file,
110
     * to save HTTP requests.
597 daniel-mar 111
     *
112
     * @param string   $source  The file to combine imports for
113
     * @param string   $content The CSS content to combine imports for
114
     * @param string[] $parents Parent paths, for circular reference checks
115
     *
116
     * @return string
117
     *
118
     * @throws FileImportException
119
     */
120
    protected function combineImports($source, $content, $parents)
121
    {
122
        $importRegexes = array(
123
            // @import url(xxx)
124
            '/
125
            # import statement
126
            @import
127
 
128
            # whitespace
129
            \s+
130
 
131
                # open url()
132
                url\(
133
 
134
                    # (optional) open path enclosure
135
                    (?P<quotes>["\']?)
136
 
137
                        # fetch path
138
                        (?P<path>.+?)
139
 
140
                    # (optional) close path enclosure
141
                    (?P=quotes)
142
 
143
                # close url()
144
                \)
145
 
146
                # (optional) trailing whitespace
147
                \s*
148
 
149
                # (optional) media statement(s)
150
                (?P<media>[^;]*)
151
 
152
                # (optional) trailing whitespace
153
                \s*
154
 
155
            # (optional) closing semi-colon
156
            ;?
157
 
158
            /ix',
159
 
160
            // @import 'xxx'
161
            '/
162
 
163
            # import statement
164
            @import
165
 
166
            # whitespace
167
            \s+
168
 
169
                # open path enclosure
170
                (?P<quotes>["\'])
171
 
172
                    # fetch path
173
                    (?P<path>.+?)
174
 
175
                # close path enclosure
176
                (?P=quotes)
177
 
178
                # (optional) trailing whitespace
179
                \s*
180
 
181
                # (optional) media statement(s)
182
                (?P<media>[^;]*)
183
 
184
                # (optional) trailing whitespace
185
                \s*
186
 
187
            # (optional) closing semi-colon
188
            ;?
189
 
190
            /ix',
191
        );
192
 
193
        // find all relative imports in css
194
        $matches = array();
195
        foreach ($importRegexes as $importRegex) {
196
            if (preg_match_all($importRegex, $content, $regexMatches, PREG_SET_ORDER)) {
197
                $matches = array_merge($matches, $regexMatches);
198
            }
199
        }
200
 
201
        $search = array();
202
        $replace = array();
203
 
204
        // loop the matches
205
        foreach ($matches as $match) {
206
            // get the path for the file that will be imported
1042 daniel-mar 207
            $importPath = dirname($source) . '/' . $match['path'];
597 daniel-mar 208
 
209
            // only replace the import with the content if we can grab the
210
            // content of the file
211
            if (!$this->canImportByPath($match['path']) || !$this->canImportFile($importPath)) {
212
                continue;
213
            }
214
 
215
            // check if current file was not imported previously in the same
216
            // import chain.
217
            if (in_array($importPath, $parents)) {
1042 daniel-mar 218
                throw new FileImportException('Failed to import file "' . $importPath . '": circular reference detected.');
597 daniel-mar 219
            }
220
 
221
            // grab referenced file & minify it (which may include importing
222
            // yet other @import statements recursively)
223
            $minifier = new self($importPath);
224
            $minifier->setMaxImportSize($this->maxImportSize);
225
            $minifier->setImportExtensions($this->importExtensions);
226
            $importContent = $minifier->execute($source, $parents);
227
 
228
            // check if this is only valid for certain media
229
            if (!empty($match['media'])) {
1042 daniel-mar 230
                $importContent = '@media ' . $match['media'] . '{' . $importContent . '}';
597 daniel-mar 231
            }
232
 
233
            // add to replacement array
234
            $search[] = $match[0];
235
            $replace[] = $importContent;
236
        }
237
 
238
        // replace the import statements
239
        return str_replace($search, $replace, $content);
240
    }
241
 
242
    /**
243
     * Import files into the CSS, base64-ized.
244
     *
245
     * @url(image.jpg) images will be loaded and their content merged into the
246
     * original file, to save HTTP requests.
247
     *
248
     * @param string $source  The file to import files for
249
     * @param string $content The CSS content to import files for
250
     *
251
     * @return string
252
     */
253
    protected function importFiles($source, $content)
254
    {
255
        $regex = '/url\((["\']?)(.+?)\\1\)/i';
256
        if ($this->importExtensions && preg_match_all($regex, $content, $matches, PREG_SET_ORDER)) {
257
            $search = array();
258
            $replace = array();
259
 
260
            // loop the matches
261
            foreach ($matches as $match) {
262
                $extension = substr(strrchr($match[2], '.'), 1);
263
                if ($extension && !array_key_exists($extension, $this->importExtensions)) {
264
                    continue;
265
                }
266
 
267
                // get the path for the file that will be imported
268
                $path = $match[2];
1042 daniel-mar 269
                $path = dirname($source) . '/' . $path;
597 daniel-mar 270
 
271
                // only replace the import with the content if we're able to get
272
                // the content of the file, and it's relatively small
273
                if ($this->canImportFile($path) && $this->canImportBySize($path)) {
274
                    // grab content && base64-ize
275
                    $importContent = $this->load($path);
276
                    $importContent = base64_encode($importContent);
277
 
278
                    // build replacement
279
                    $search[] = $match[0];
1042 daniel-mar 280
                    $replace[] = 'url(' . $this->importExtensions[$extension] . ';base64,' . $importContent . ')';
597 daniel-mar 281
                }
282
            }
283
 
284
            // replace the import statements
285
            $content = str_replace($search, $replace, $content);
286
        }
287
 
288
        return $content;
289
    }
290
 
291
    /**
292
     * Minify the data.
293
     * Perform CSS optimizations.
294
     *
295
     * @param string[optional] $path    Path to write the data to
1042 daniel-mar 296
     * @param string[] $parents Parent paths, for circular reference checks
597 daniel-mar 297
     *
298
     * @return string The minified data
299
     */
300
    public function execute($path = null, $parents = array())
301
    {
302
        $content = '';
303
 
304
        // loop CSS data (raw data and files)
305
        foreach ($this->data as $source => $css) {
306
            /*
307
             * Let's first take out strings & comments, since we can't just
308
             * remove whitespace anywhere. If whitespace occurs inside a string,
309
             * we should leave it alone. E.g.:
310
             * p { content: "a   test" }
311
             */
312
            $this->extractStrings();
313
            $this->stripComments();
314
            $this->extractMath();
315
            $this->extractCustomProperties();
316
            $css = $this->replace($css);
317
 
318
            $css = $this->stripWhitespace($css);
1469 daniel-mar 319
            $css = $this->convertLegacyColors($css);
320
            $css = $this->cleanupModernColors($css);
321
            $css = $this->shortenHEXColors($css);
597 daniel-mar 322
            $css = $this->shortenZeroes($css);
323
            $css = $this->shortenFontWeights($css);
324
            $css = $this->stripEmptyTags($css);
325
 
326
            // restore the string we've extracted earlier
327
            $css = $this->restoreExtractedData($css);
328
 
329
            $source = is_int($source) ? '' : $source;
330
            $parents = $source ? array_merge($parents, array($source)) : $parents;
331
            $css = $this->combineImports($source, $css, $parents);
332
            $css = $this->importFiles($source, $css);
333
 
334
            /*
335
             * If we'll save to a new path, we'll have to fix the relative paths
336
             * to be relative no longer to the source file, but to the new path.
337
             * If we don't write to a file, fall back to same path so no
338
             * conversion happens (because we still want it to go through most
339
             * of the move code, which also addresses url() & @import syntax...)
340
             */
341
            $converter = $this->getPathConverter($source, $path ?: $source);
342
            $css = $this->move($converter, $css);
343
 
344
            // combine css
345
            $content .= $css;
346
        }
347
 
348
        $content = $this->moveImportsToTop($content);
349
 
350
        return $content;
351
    }
352
 
353
    /**
354
     * Moving a css file should update all relative urls.
355
     * Relative references (e.g. ../images/image.gif) in a certain css file,
356
     * will have to be updated when a file is being saved at another location
357
     * (e.g. ../../images/image.gif, if the new CSS file is 1 folder deeper).
358
     *
359
     * @param ConverterInterface $converter Relative path converter
360
     * @param string             $content   The CSS content to update relative urls for
361
     *
362
     * @return string
363
     */
364
    protected function move(ConverterInterface $converter, $content)
365
    {
366
        /*
367
         * Relative path references will usually be enclosed by url(). @import
368
         * is an exception, where url() is not necessary around the path (but is
369
         * allowed).
370
         * This *could* be 1 regular expression, where both regular expressions
371
         * in this array are on different sides of a |. But we're using named
372
         * patterns in both regexes, the same name on both regexes. This is only
373
         * possible with a (?J) modifier, but that only works after a fairly
374
         * recent PCRE version. That's why I'm doing 2 separate regular
375
         * expressions & combining the matches after executing of both.
376
         */
377
        $relativeRegexes = array(
378
            // url(xxx)
379
            '/
380
            # open url()
381
            url\(
382
 
383
                \s*
384
 
385
                # open path enclosure
386
                (?P<quotes>["\'])?
387
 
388
                    # fetch path
389
                    (?P<path>.+?)
390
 
391
                # close path enclosure
392
                (?(quotes)(?P=quotes))
393
 
394
                \s*
395
 
396
            # close url()
397
            \)
398
 
399
            /ix',
400
 
401
            // @import "xxx"
402
            '/
403
            # import statement
404
            @import
405
 
406
            # whitespace
407
            \s+
408
 
409
                # we don\'t have to check for @import url(), because the
410
                # condition above will already catch these
411
 
412
                # open path enclosure
413
                (?P<quotes>["\'])
414
 
415
                    # fetch path
416
                    (?P<path>.+?)
417
 
418
                # close path enclosure
419
                (?P=quotes)
420
 
421
            /ix',
422
        );
423
 
424
        // find all relative urls in css
425
        $matches = array();
426
        foreach ($relativeRegexes as $relativeRegex) {
427
            if (preg_match_all($relativeRegex, $content, $regexMatches, PREG_SET_ORDER)) {
428
                $matches = array_merge($matches, $regexMatches);
429
            }
430
        }
431
 
432
        $search = array();
433
        $replace = array();
434
 
435
        // loop all urls
436
        foreach ($matches as $match) {
437
            // determine if it's a url() or an @import match
438
            $type = (strpos($match[0], '@import') === 0 ? 'import' : 'url');
439
 
440
            $url = $match['path'];
441
            if ($this->canImportByPath($url)) {
442
                // attempting to interpret GET-params makes no sense, so let's discard them for awhile
443
                $params = strrchr($url, '?');
444
                $url = $params ? substr($url, 0, -strlen($params)) : $url;
445
 
446
                // fix relative url
447
                $url = $converter->convert($url);
448
 
449
                // now that the path has been converted, re-apply GET-params
450
                $url .= $params;
451
            }
452
 
453
            /*
454
             * Urls with control characters above 0x7e should be quoted.
455
             * According to Mozilla's parser, whitespace is only allowed at the
456
             * end of unquoted urls.
457
             * Urls with `)` (as could happen with data: uris) should also be
458
             * quoted to avoid being confused for the url() closing parentheses.
459
             * And urls with a # have also been reported to cause issues.
460
             * Urls with quotes inside should also remain escaped.
461
             *
462
             * @see https://developer.mozilla.org/nl/docs/Web/CSS/url#The_url()_functional_notation
463
             * @see https://hg.mozilla.org/mozilla-central/rev/14abca4e7378
464
             * @see https://github.com/matthiasmullie/minify/issues/193
465
             */
466
            $url = trim($url);
467
            if (preg_match('/[\s\)\'"#\x{7f}-\x{9f}]/u', $url)) {
468
                $url = $match['quotes'] . $url . $match['quotes'];
469
            }
470
 
471
            // build replacement
472
            $search[] = $match[0];
473
            if ($type === 'url') {
1042 daniel-mar 474
                $replace[] = 'url(' . $url . ')';
597 daniel-mar 475
            } elseif ($type === 'import') {
1042 daniel-mar 476
                $replace[] = '@import "' . $url . '"';
597 daniel-mar 477
            }
478
        }
479
 
480
        // replace urls
481
        return str_replace($search, $replace, $content);
482
    }
483
 
484
    /**
1469 daniel-mar 485
     * Shorthand HEX color codes.
486
     * #FF0000FF -> #f00 -> red
487
     * #FF00FF00 -> transparent.
597 daniel-mar 488
     *
1469 daniel-mar 489
     * @param string $content The CSS content to shorten the HEX color codes for
597 daniel-mar 490
     *
491
     * @return string
492
     */
1469 daniel-mar 493
    protected function shortenHexColors($content)
597 daniel-mar 494
    {
1469 daniel-mar 495
        // shorten repeating patterns within HEX ..
496
        $content = preg_replace('/(?<=[: ])#([0-9a-f])\\1([0-9a-f])\\2([0-9a-f])\\3(?:([0-9a-f])\\4)?(?=[; }])/i', '#$1$2$3$4', $content);
597 daniel-mar 497
 
1469 daniel-mar 498
        // remove alpha channel if it's pointless ..
499
        $content = preg_replace('/(?<=[: ])#([0-9a-f]{6})ff(?=[; }])/i', '#$1', $content);
500
        $content = preg_replace('/(?<=[: ])#([0-9a-f]{3})f(?=[; }])/i', '#$1', $content);
597 daniel-mar 501
 
1469 daniel-mar 502
        // replace `transparent` with shortcut ..
503
        $content = preg_replace('/(?<=[: ])#[0-9a-f]{6}00(?=[; }])/i', '#fff0', $content);
504
 
597 daniel-mar 505
        $colors = array(
1469 daniel-mar 506
            // make these more readable
507
            '#00f' => 'blue',
508
            '#dc143c' => 'crimson',
509
            '#0ff' => 'cyan',
510
            '#8b0000' => 'darkred',
511
            '#696969' => 'dimgray',
512
            '#ff69b4' => 'hotpink',
513
            '#0f0' => 'lime',
514
            '#fdf5e6' => 'oldlace',
515
            '#87ceeb' => 'skyblue',
516
            '#d8bfd8' => 'thistle',
597 daniel-mar 517
            // we can shorten some even more by replacing them with their color name
1469 daniel-mar 518
            '#f0ffff' => 'azure',
519
            '#f5f5dc' => 'beige',
520
            '#ffe4c4' => 'bisque',
521
            '#a52a2a' => 'brown',
522
            '#ff7f50' => 'coral',
523
            '#ffd700' => 'gold',
597 daniel-mar 524
            '#808080' => 'gray',
525
            '#008000' => 'green',
1469 daniel-mar 526
            '#4b0082' => 'indigo',
527
            '#fffff0' => 'ivory',
528
            '#f0e68c' => 'khaki',
529
            '#faf0e6' => 'linen',
597 daniel-mar 530
            '#800000' => 'maroon',
531
            '#000080' => 'navy',
532
            '#808000' => 'olive',
1469 daniel-mar 533
            '#ffa500' => 'orange',
534
            '#da70d6' => 'orchid',
535
            '#cd853f' => 'peru',
536
            '#ffc0cb' => 'pink',
537
            '#dda0dd' => 'plum',
597 daniel-mar 538
            '#800080' => 'purple',
1469 daniel-mar 539
            '#f00' => 'red',
540
            '#fa8072' => 'salmon',
541
            '#a0522d' => 'sienna',
542
            '#c0c0c0' => 'silver',
543
            '#fffafa' => 'snow',
544
            '#d2b48c' => 'tan',
545
            '#008080' => 'teal',
546
            '#ff6347' => 'tomato',
547
            '#ee82ee' => 'violet',
548
            '#f5deb3' => 'wheat',
597 daniel-mar 549
            // or the other way around
1469 daniel-mar 550
            'black' => '#000',
551
            'fuchsia' => '#f0f',
552
            'magenta' => '#f0f',
553
            'white' => '#fff',
554
            'yellow' => '#ff0',
555
            // and also `transparent`
556
            'transparent' => '#fff0',
597 daniel-mar 557
        );
558
 
559
        return preg_replace_callback(
1042 daniel-mar 560
            '/(?<=[: ])(' . implode('|', array_keys($colors)) . ')(?=[; }])/i',
597 daniel-mar 561
            function ($match) use ($colors) {
1469 daniel-mar 562
                return $colors[strtolower($match[0])];
597 daniel-mar 563
            },
564
            $content
565
        );
566
    }
567
 
568
    /**
1469 daniel-mar 569
     * Convert RGB|HSL color codes.
570
     * rgb(255,0,0,.5) -> rgb(255 0 0 / .5).
571
     * rgb(255,0,0) -> #f00.
572
     *
573
     * @param string $content The CSS content to shorten the RGB color codes for
574
     *
575
     * @return string
576
     */
577
    protected function convertLegacyColors($content)
578
    {
579
        /*
580
          https://drafts.csswg.org/css-color/#color-syntax-legacy
581
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/rgb
582
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/hsl
583
        */
584
 
585
        // convert legacy color syntax
586
        $content = preg_replace('/(rgb|hsl)a?\(([^,\s]+)\s*,\s*([^,\s]+)\s*,\s*([^,\s]+)\s*,\s*([^\s\)]+)\)/i', '$1($2 $3 $4 / $5)', $content);
587
        $content = preg_replace('/(rgb|hsl)a?\(([^,\s]+)\s*,\s*([^,\s]+)\s*,\s*([^,\s]+)\)/i', '$1($2 $3 $4)', $content);
588
 
589
        // convert `rgb` to `hex`
590
        $dec = '([01]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])'; // [000-255] THX @ https://www.regular-expressions.info/numericranges.html
591
 
592
        return preg_replace_callback(
593
            "/rgb\($dec $dec $dec\)/i",
594
            function ($match) {
595
                return sprintf('#%02x%02x%02x', $match[1], $match[2], $match[3]);
596
            },
597
            $content
598
        );
599
    }
600
 
601
    /**
602
     * Cleanup RGB|HSL|HWB|LCH|LAB
603
     * rgb(255 0 0 / 1) -> rgb(255 0 0).
604
     * rgb(255 0 0 / 0) -> transparent.
605
     *
606
     * @param string $content The CSS content to cleanup HSL|HWB|LCH|LAB
607
     *
608
     * @return string
609
     */
610
    protected function cleanupModernColors($content)
611
    {
612
        /*
613
          https://drafts.csswg.org/css-color/#color-syntax-modern
614
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/hwb
615
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/lch
616
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/lab
617
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/oklch
618
          https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/oklab
619
        */
620
        $tag = '(rgb|hsl|hwb|(?:(?:ok)?(?:lch|lab)))';
621
 
622
        // remove alpha channel if it's pointless ..
623
        $content = preg_replace('/' . $tag . '\(([^\s]+)\s+([^\s]+)\s+([^\s]+)\s+\/\s+1(?:[\.\d]*|00%)?\)/i', '$1($2 $3 $4)', $content);
624
 
625
        // replace `transparent` with shortcut ..
626
        $content = preg_replace('/' . $tag . '\([^\s]+\s+[^\s]+\s+[^\s]+\s+\/\s+0(?:[\.0%]*)?\)/i', '#fff0', $content);
627
 
628
        return $content;
629
    }
630
 
631
    /**
597 daniel-mar 632
     * Shorten CSS font weights.
633
     *
634
     * @param string $content The CSS content to shorten the font weights for
635
     *
636
     * @return string
637
     */
638
    protected function shortenFontWeights($content)
639
    {
640
        $weights = array(
641
            'normal' => 400,
642
            'bold' => 700,
643
        );
644
 
645
        $callback = function ($match) use ($weights) {
1042 daniel-mar 646
            return $match[1] . $weights[$match[2]];
597 daniel-mar 647
        };
648
 
1042 daniel-mar 649
        return preg_replace_callback('/(font-weight\s*:\s*)(' . implode('|', array_keys($weights)) . ')(?=[;}])/', $callback, $content);
597 daniel-mar 650
    }
651
 
652
    /**
653
     * Shorthand 0 values to plain 0, instead of e.g. -0em.
654
     *
655
     * @param string $content The CSS content to shorten the zero values for
656
     *
657
     * @return string
658
     */
659
    protected function shortenZeroes($content)
660
    {
661
        // we don't want to strip units in `calc()` expressions:
662
        // `5px - 0px` is valid, but `5px - 0` is not
663
        // `10px * 0` is valid (equates to 0), and so is `10 * 0px`, but
664
        // `10 * 0` is invalid
665
        // we've extracted calcs earlier, so we don't need to worry about this
666
 
667
        // reusable bits of code throughout these regexes:
668
        // before & after are used to make sure we don't match lose unintended
669
        // 0-like values (e.g. in #000, or in http://url/1.0)
670
        // units can be stripped from 0 values, or used to recognize non 0
671
        // values (where wa may be able to strip a .0 suffix)
672
        $before = '(?<=[:(, ])';
673
        $after = '(?=[ ,);}])';
674
        $units = '(em|ex|%|px|cm|mm|in|pt|pc|ch|rem|vh|vw|vmin|vmax|vm)';
675
 
676
        // strip units after zeroes (0px -> 0)
677
        // NOTE: it should be safe to remove all units for a 0 value, but in
678
        // practice, Webkit (especially Safari) seems to stumble over at least
679
        // 0%, potentially other units as well. Only stripping 'px' for now.
680
        // @see https://github.com/matthiasmullie/minify/issues/60
1042 daniel-mar 681
        $content = preg_replace('/' . $before . '(-?0*(\.0+)?)(?<=0)px' . $after . '/', '\\1', $content);
597 daniel-mar 682
 
683
        // strip 0-digits (.0 -> 0)
1042 daniel-mar 684
        $content = preg_replace('/' . $before . '\.0+' . $units . '?' . $after . '/', '0\\1', $content);
597 daniel-mar 685
        // strip trailing 0: 50.10 -> 50.1, 50.10px -> 50.1px
1042 daniel-mar 686
        $content = preg_replace('/' . $before . '(-?[0-9]+\.[0-9]+)0+' . $units . '?' . $after . '/', '\\1\\2', $content);
597 daniel-mar 687
        // strip trailing 0: 50.00 -> 50, 50.00px -> 50px
1042 daniel-mar 688
        $content = preg_replace('/' . $before . '(-?[0-9]+)\.0+' . $units . '?' . $after . '/', '\\1\\2', $content);
597 daniel-mar 689
        // strip leading 0: 0.1 -> .1, 01.1 -> 1.1
1042 daniel-mar 690
        $content = preg_replace('/' . $before . '(-?)0+([0-9]*\.[0-9]+)' . $units . '?' . $after . '/', '\\1\\2\\3', $content);
597 daniel-mar 691
 
692
        // strip negative zeroes (-0 -> 0) & truncate zeroes (00 -> 0)
1042 daniel-mar 693
        $content = preg_replace('/' . $before . '-?0+' . $units . '?' . $after . '/', '0\\1', $content);
597 daniel-mar 694
 
695
        // IE doesn't seem to understand a unitless flex-basis value (correct -
696
        // it goes against the spec), so let's add it in again (make it `%`,
697
        // which is only 1 char: 0%, 0px, 0 anything, it's all just the same)
698
        // @see https://developer.mozilla.org/nl/docs/Web/CSS/flex
699
        $content = preg_replace('/flex:([0-9]+\s[0-9]+\s)0([;\}])/', 'flex:${1}0%${2}', $content);
700
        $content = preg_replace('/flex-basis:0([;\}])/', 'flex-basis:0%${1}', $content);
701
 
702
        return $content;
703
    }
704
 
705
    /**
706
     * Strip empty tags from source code.
707
     *
708
     * @param string $content
709
     *
710
     * @return string
711
     */
712
    protected function stripEmptyTags($content)
713
    {
714
        $content = preg_replace('/(?<=^)[^\{\};]+\{\s*\}/', '', $content);
715
        $content = preg_replace('/(?<=(\}|;))[^\{\};]+\{\s*\}/', '', $content);
716
 
717
        return $content;
718
    }
719
 
720
    /**
721
     * Strip comments from source code.
722
     */
723
    protected function stripComments()
724
    {
1308 daniel-mar 725
        $this->stripMultilineComments();
597 daniel-mar 726
    }
727
 
728
    /**
729
     * Strip whitespace.
730
     *
731
     * @param string $content The CSS content to strip the whitespace for
732
     *
733
     * @return string
734
     */
735
    protected function stripWhitespace($content)
736
    {
737
        // remove leading & trailing whitespace
738
        $content = preg_replace('/^\s*/m', '', $content);
739
        $content = preg_replace('/\s*$/m', '', $content);
740
 
741
        // replace newlines with a single space
742
        $content = preg_replace('/\s+/', ' ', $content);
743
 
744
        // remove whitespace around meta characters
745
        // inspired by stackoverflow.com/questions/15195750/minify-compress-css-with-regex
746
        $content = preg_replace('/\s*([\*$~^|]?+=|[{};,>~]|!important\b)\s*/', '$1', $content);
747
        $content = preg_replace('/([\[(:>\+])\s+/', '$1', $content);
748
        $content = preg_replace('/\s+([\]\)>\+])/', '$1', $content);
749
        $content = preg_replace('/\s+(:)(?![^\}]*\{)/', '$1', $content);
750
 
751
        // whitespace around + and - can only be stripped inside some pseudo-
752
        // classes, like `:nth-child(3+2n)`
753
        // not in things like `calc(3px + 2px)`, shorthands like `3px -2px`, or
754
        // selectors like `div.weird- p`
755
        $pseudos = array('nth-child', 'nth-last-child', 'nth-last-of-type', 'nth-of-type');
1042 daniel-mar 756
        $content = preg_replace('/:(' . implode('|', $pseudos) . ')\(\s*([+-]?)\s*(.+?)\s*([+-]?)\s*(.*?)\s*\)/', ':$1($2$3$4$5)', $content);
597 daniel-mar 757
 
758
        // remove semicolon/whitespace followed by closing bracket
759
        $content = str_replace(';}', '}', $content);
760
 
761
        return trim($content);
762
    }
763
 
764
    /**
765
     * Replace all occurrences of functions that may contain math, where
1042 daniel-mar 766
     * whitespace around operators needs to be preserved (e.g. calc, clamp).
597 daniel-mar 767
     */
768
    protected function extractMath()
769
    {
770
        $functions = array('calc', 'clamp', 'min', 'max');
1042 daniel-mar 771
        $pattern = '/\b(' . implode('|', $functions) . ')(\(.+?)(?=$|;|})/m';
597 daniel-mar 772
 
773
        // PHP only supports $this inside anonymous functions since 5.4
774
        $minifier = $this;
775
        $callback = function ($match) use ($minifier, $pattern, &$callback) {
776
            $function = $match[1];
777
            $length = strlen($match[2]);
778
            $expr = '';
779
            $opened = 0;
780
 
781
            // the regular expression for extracting math has 1 significant problem:
782
            // it can't determine the correct closing parenthesis...
783
            // instead, it'll match a larger portion of code to where it's certain that
784
            // the calc() musts have ended, and we'll figure out which is the correct
785
            // closing parenthesis here, by counting how many have opened
1042 daniel-mar 786
            for ($i = 0; $i < $length; ++$i) {
597 daniel-mar 787
                $char = $match[2][$i];
788
                $expr .= $char;
789
                if ($char === '(') {
1042 daniel-mar 790
                    ++$opened;
597 daniel-mar 791
                } elseif ($char === ')' && --$opened === 0) {
792
                    break;
793
                }
794
            }
795
 
796
            // now that we've figured out where the calc() starts and ends, extract it
797
            $count = count($minifier->extracted);
1042 daniel-mar 798
            $placeholder = 'math(' . $count . ')';
799
            $minifier->extracted[$placeholder] = $function . '(' . trim(substr($expr, 1, -1)) . ')';
597 daniel-mar 800
 
801
            // and since we've captured more code than required, we may have some leftover
802
            // calc() in here too - go recursive on the remaining but of code to go figure
803
            // that out and extract what is needed
1042 daniel-mar 804
            $rest = $minifier->str_replace_first($function . $expr, '', $match[0]);
597 daniel-mar 805
            $rest = preg_replace_callback($pattern, $callback, $rest);
806
 
1042 daniel-mar 807
            return $placeholder . $rest;
597 daniel-mar 808
        };
809
 
810
        $this->registerPattern($pattern, $callback);
811
    }
812
 
813
    /**
814
     * Replace custom properties, whose values may be used in scenarios where
1042 daniel-mar 815
     * we wouldn't want them to be minified (e.g. inside calc).
597 daniel-mar 816
     */
817
    protected function extractCustomProperties()
818
    {
819
        // PHP only supports $this inside anonymous functions since 5.4
820
        $minifier = $this;
821
        $this->registerPattern(
925 daniel-mar 822
            '/(?<=^|[;}{])\s*(--[^:;{}"\'\s]+)\s*:([^;{}]+)/m',
597 daniel-mar 823
            function ($match) use ($minifier) {
1042 daniel-mar 824
                $placeholder = '--custom-' . count($minifier->extracted) . ':0';
825
                $minifier->extracted[$placeholder] = $match[1] . ':' . trim($match[2]);
826
 
597 daniel-mar 827
                return $placeholder;
828
            }
829
        );
830
    }
831
 
832
    /**
833
     * Check if file is small enough to be imported.
834
     *
835
     * @param string $path The path to the file
836
     *
837
     * @return bool
838
     */
839
    protected function canImportBySize($path)
840
    {
841
        return ($size = @filesize($path)) && $size <= $this->maxImportSize * 1024;
842
    }
843
 
844
    /**
845
     * Check if file a file can be imported, going by the path.
846
     *
847
     * @param string $path
848
     *
849
     * @return bool
850
     */
851
    protected function canImportByPath($path)
852
    {
853
        return preg_match('/^(data:|https?:|\\/)/', $path) === 0;
854
    }
855
 
856
    /**
857
     * Return a converter to update relative paths to be relative to the new
858
     * destination.
859
     *
860
     * @param string $source
861
     * @param string $target
862
     *
863
     * @return ConverterInterface
864
     */
865
    protected function getPathConverter($source, $target)
866
    {
867
        return new Converter($source, $target);
868
    }
869
}