feat(css): globales CSS bearbeiten (lit/divi-custom-css-get und -update)
WordPress „Zusätzliches CSS“ (in Divi „Eigenes CSS“) über die Design-Pipeline: Probelauf mit Zeilen-Diff, design_rev, Bestätigung, Snapshot, Rollback und Wiederherstellen (Bereich custom_css). Der Guard lehnt </style, <script, expression(, javascript: und neue @import ab und warnt bei fremden Hosts; nur Neues zählt, Bestehendes blockiert keine Änderung. Erfordert edit_css und die Divi-Rolle Theme-Anpassung. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
This commit is contained in:
Jan-Niclas Loosen
co-authored by
Claude Sonnet 5.5
Claude Sonnet 5.5
parent
96fa58188b
commit
ac333a164c
@@ -0,0 +1,277 @@
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<?php
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declare(strict_types=1);
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namespace LIT\MCP\Integrations\Divi\Design;
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use RuntimeException;
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defined('ABSPATH') || exit;
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/**
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* What may be written as site-wide custom CSS (security audit 2026-11, threat model for lit/divi-custom-css-update).
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* check() returns refusals (nothing is stored) and warnings (shown in the dry run).
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*
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* Refused: a way out of the style element, script carriers of old browsers, and every @import – it loads a
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* stylesheet the site does not control, and a filter that tries to tell "our" imports from foreign ones is read
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* differently by the browser (tabs and newlines inside a URL, escapes, user info before the host: the red-team run
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* of this class found nine ways). Only what a change introduces counts: an @import that is already in the text,
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* character for character, does not block an unrelated edit. Warned: references to other hosts, unbalanced braces,
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* rules that hide the page.
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*
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* Every pattern runs on the raw text, on the text with CSS escapes decoded ("\3c /style"), with comments removed
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* ("exp/**\/ression") and with whitespace and control characters removed ("java<TAB>script"), because browsers read
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* those the same way a filter on the raw text does not. A regex that cannot finish (PCRE limit) is a refusal, never
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* a pass.
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*/
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final class CustomCssGuard
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{
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private const MAX_BYTES = SnapshotStore::MAX_BYTES;
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/** @var array<string, string> Pattern => why it is refused. */
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private const FORBIDDEN = [
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'/<\/style/i' => '„</style“ würde den Style-Block der Website beenden',
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'/<script/i' => '„<script“ gehört nicht in CSS',
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'/<!--|-->/' => 'HTML-Kommentarmarken („<!--“, „-->“) gehören nicht in CSS',
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'/expression\s*\(/i' => '„expression(“ führt in alten Browsern Skript aus',
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'/(?:java|vb)script\s*:/i' => '„javascript:“ und „vbscript:“ sind nicht erlaubt',
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'/behavior\s*:|-moz-binding/i' => '„behavior“ und „-moz-binding“ laden in alten Browsern Skript',
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];
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/** An @import with what it names, up to the end of the statement: the unit compared with the old text. */
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private const IMPORT = '/@import[^;{}]{0,300}/i';
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/** Anything that names a host: "//host", "scheme://host", with user info and port. */
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private const HOST = '~(?:[a-z][a-z0-9+.-]*:)?//([^\s/?#"\'()\\\\<>]+)~i';
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/** Hosts of XML namespaces inside inline SVG – no request goes there. */
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private const NAMESPACE_HOSTS = ['www.w3.org'];
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/** A rule on * / html / body / #page-container that hides the page or makes it unclickable. */
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private const HIDES_PAGE = '/(?:^|[}\s,])(?:\*|html|body|#page-container)\s*(?:,[^{}]*)?\{[^}]*'
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. '(?:display\s*:\s*none|visibility\s*:\s*hidden|pointer-events\s*:\s*none|opacity\s*:\s*0(?![.\d]))/i';
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/** @param string|null $siteHost Host of this site; null = the host of home_url(), read when first needed. */
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public function __construct(private ?string $siteHost = null)
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{
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}
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/**
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* @param string $existing The text before the change: what it already contains does not block the change.
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* @return array{errors: list<string>, warnings: list<string>}
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*/
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public function check(string $css, string $existing = ''): array
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{
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$errors = [];
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if (strlen($css) > self::MAX_BYTES) {
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$errors[] = sprintf('Das CSS ist größer als %d Bytes', self::MAX_BYTES);
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}
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if (! mb_check_encoding($css, 'UTF-8')) {
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$errors[] = 'Das CSS ist kein gültiges UTF-8';
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}
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if (str_contains($css, "\0")) {
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$errors[] = 'Das CSS enthält Null-Zeichen';
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}
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if ($errors !== []) {
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return ['errors' => $errors, 'warnings' => []];
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}
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try {
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$known = $existing === '' || ! mb_check_encoding($existing, 'UTF-8') ? [] : $this->issues($existing);
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foreach ($this->issues($css) as $why => $count) {
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if ($count > ($known[$why] ?? 0)) {
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$errors[] = $why;
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}
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}
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return ['errors' => $errors, 'warnings' => $errors === [] ? $this->warnings($css) : []];
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} catch (RuntimeException) {
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return ['errors' => ['Das CSS ist zu verschachtelt, um es sicher zu prüfen'], 'warnings' => []];
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}
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}
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/**
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* Every refusal reason found in $css with how often – the same text twice counts twice.
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*
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* @return array<string, int>
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* @throws RuntimeException When a pattern cannot finish.
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*/
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private function issues(string $css): array
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{
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$plain = self::withoutComments($css);
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$views = [$css, self::decoded($css), self::decoded($plain), self::compact(self::decoded($plain))];
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$found = [];
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foreach (self::FORBIDDEN as $pattern => $why) {
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$count = 0;
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foreach ($views as $view) {
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$count = max($count, self::count($pattern, $view));
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}
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if ($count > 0) {
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$found[$why] = $count;
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}
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}
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// Not the compacted view: it would list every import a second time in another spelling.
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foreach (array_slice($views, 0, 3) as $view) {
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$targets = [];
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foreach (self::imports($view) as $import) {
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$key = sprintf('@import ist nicht erlaubt (lädt ein weiteres Stylesheet): „%s“', self::tidy($import));
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$targets[$key] = ($targets[$key] ?? 0) + 1;
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}
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foreach ($targets as $key => $count) {
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$found[$key] = max($found[$key] ?? 0, $count);
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}
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}
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return $found;
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}
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/** @return list<string> */
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private function warnings(string $css): array
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{
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$warnings = [];
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$hosts = $this->mentionedHosts($css);
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if ($hosts !== []) {
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$warnings[] = sprintf(
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'Verweist auf %s – prüfen, ob das gewollt ist (Datenschutz, Verfügbarkeit).',
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implode(', ', array_map(static fn (string $host): string => '„' . $host . '“', $hosts))
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);
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}
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$withoutStrings = preg_replace('/"(?:[^"\\\\]|\\\\.)*"|\'(?:[^\'\\\\]|\\\\.)*\'/s', '""', $css);
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$withoutStrings = is_string($withoutStrings) ? $withoutStrings : $css;
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if (substr_count($withoutStrings, '{') !== substr_count($withoutStrings, '}')) {
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$warnings[] = 'Die geschweiften Klammern sind nicht ausgeglichen; eine offene Regel verschluckt die '
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. 'folgenden.';
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}
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// A limit hit is no verdict: this warning is advice, the refusals above are the guard.
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if (preg_match(self::HIDES_PAGE, $withoutStrings) === 1) {
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$warnings[] = 'Eine Regel auf *, html, body oder #page-container blendet die Seite aus oder macht sie '
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. 'unbedienbar.';
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}
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return $warnings;
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}
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/**
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* Hosts other than this site that the text names anywhere – also inside strings, image-set() or a comment, since
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* the browser decides what it loads, not the notation. The host is read the way a URL parser does: tabs and
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* newlines are dropped, user info ("name@") is not the host, a port is cut.
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*
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* @return list<string>
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*/
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private function mentionedHosts(string $css): array
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{
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$found = [];
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foreach ([$css, self::decoded($css)] as $view) {
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preg_match_all(self::HOST, str_replace(["\t", "\n", "\r"], '', $view), $matches);
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foreach ($matches[1] ?? [] as $authority) {
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$host = strtolower((string) preg_replace('/:\d*$/', '', self::afterUserInfo((string) $authority)));
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if ($host !== '' && $host !== $this->siteHost() && ! in_array($host, self::NAMESPACE_HOSTS, true)) {
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$found[$host] = true;
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}
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}
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}
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return array_slice(array_keys($found), 0, 5);
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}
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private static function afterUserInfo(string $authority): string
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{
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$at = strrpos($authority, '@');
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return $at === false ? $authority : substr($authority, $at + 1);
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}
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private function siteHost(): string
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{
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$this->siteHost ??= (string) wp_parse_url(home_url(), PHP_URL_HOST);
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return strtolower($this->siteHost);
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}
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/** @return list<string> */
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private static function imports(string $css): array
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{
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if (preg_match_all(self::IMPORT, $css, $matches) === false) {
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throw new RuntimeException('pattern did not finish');
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}
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return $matches[0];
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}
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/**
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* Comments as the browser removes them: from the opening mark to the next closing mark or – unclosed – to the
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* end. Replaced by a space (CSS reads a comment as a token break). A strpos() loop, not a regex: linear for any
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* input, where a regex runs into PCRE's limits.
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*/
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private static function withoutComments(string $css): string
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{
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$out = '';
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$position = 0;
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while (($start = strpos($css, '/*', $position)) !== false) {
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$out .= substr($css, $position, $start - $position) . ' ';
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$end = strpos($css, '*/', $start + 2);
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if ($end === false) {
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return $out;
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}
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$position = $end + 2;
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}
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return $out . substr($css, $position);
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}
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/** CSS escapes as a browser reads them ("\3c " is "<"); 0, surrogates and too large codes become U+FFFD. */
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private static function decoded(string $css): string
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{
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$css = preg_replace_callback(
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'/\\\\([0-9a-fA-F]{1,6})[ \t\r\n\f]?/',
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static function (array $m): string {
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$code = (int) hexdec($m[1]);
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return $code === 0 || $code > 0x10FFFF || ($code >= 0xD800 && $code <= 0xDFFF)
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? "\u{FFFD}"
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: (string) mb_chr($code, 'UTF-8');
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},
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$css
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);
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$css = is_string($css) ? preg_replace('/\\\\(?![\r\n\f])(.)/su', '$1', $css) : null;
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if (! is_string($css)) {
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throw new RuntimeException('decoding failed');
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}
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return $css;
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}
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/** No whitespace, control characters or U+FFFD, compatibility forms folded ("java<TAB>script:", full-width letters). */
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private static function compact(string $css): string
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{
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if (class_exists('Normalizer')) {
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$css = \Normalizer::normalize($css, \Normalizer::FORM_KC) ?: $css;
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}
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// U+FFFD is what an escaped null or an invalid code becomes; an old parser may have dropped it.
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$css = preg_replace('/[\x00-\x20\x7f\x{FFFD}]+/u', '', $css);
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if (! is_string($css)) {
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throw new RuntimeException('compacting failed');
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}
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return $css;
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}
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/** @throws RuntimeException When PCRE gives up (limit): no answer must never read as "nothing found". */
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private static function count(string $pattern, string $subject): int
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{
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$count = preg_match_all($pattern, $subject);
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if ($count === false) {
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throw new RuntimeException('pattern did not finish');
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}
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return $count;
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}
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private static function tidy(string $statement): string
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{
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$statement = trim((string) preg_replace('/\s+/', ' ', $statement));
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return mb_strlen($statement) > 80 ? mb_substr($statement, 0, 80) . '…' : $statement;
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}
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}
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