244 lines
10 KiB
PHP
244 lines
10 KiB
PHP
<?php
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declare(strict_types=1);
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/*
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* This file is part of the league/commonmark package.
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*
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* (c) Colin O'Dell <colinodell@gmail.com>
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*
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* Original code based on the CommonMark JS reference parser (https://bitly.com/commonmark-js)
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* - (c) John MacFarlane
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace League\CommonMark\Util;
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use League\CommonMark\Exception\InvalidArgumentException;
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use League\CommonMark\Extension\CommonMark\Node\Block\HtmlBlock;
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/**
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* Provides regular expressions and utilities for parsing Markdown
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*
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* All of the PARTIAL_ regex constants assume that they'll be used in case-insensitive searches
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* All other complete regexes provided by this class (either via constants or methods) will have case-insensitivity enabled.
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*
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* @phpcs:disable Generic.Strings.UnnecessaryStringConcat.Found
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*
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* @psalm-immutable
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*/
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final class RegexHelper
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{
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// Partial regular expressions (wrap with `/` on each side and add the case-insensitive `i` flag before use)
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public const PARTIAL_ENTITY = '&(?:#x[a-f0-9]{1,6}|#[0-9]{1,7}|[a-z][a-z0-9]{1,31});';
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public const PARTIAL_ESCAPABLE = '[!"#$%&\'()*+,.\/:;<=>?@[\\\\\]^_`{|}~-]';
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public const PARTIAL_ESCAPED_CHAR = '\\\\' . self::PARTIAL_ESCAPABLE;
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public const PARTIAL_IN_DOUBLE_QUOTES = '"(' . self::PARTIAL_ESCAPED_CHAR . '|[^"\x00])*"';
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public const PARTIAL_IN_SINGLE_QUOTES = '\'(' . self::PARTIAL_ESCAPED_CHAR . '|[^\'\x00])*\'';
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public const PARTIAL_IN_PARENS = '\\((' . self::PARTIAL_ESCAPED_CHAR . '|[^)\x00])*\\)';
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public const PARTIAL_REG_CHAR = '[^\\\\()\x00-\x20]';
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public const PARTIAL_IN_PARENS_NOSP = '\((' . self::PARTIAL_REG_CHAR . '|' . self::PARTIAL_ESCAPED_CHAR . '|\\\\)*\)';
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public const PARTIAL_TAGNAME = '[a-z][a-z0-9-]*';
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public const PARTIAL_BLOCKTAGNAME = '(?:address|article|aside|base|basefont|blockquote|body|caption|center|col|colgroup|dd|details|dialog|dir|div|dl|dt|fieldset|figcaption|figure|footer|form|frame|frameset|h1|head|header|hr|html|iframe|legend|li|link|main|menu|menuitem|nav|noframes|ol|optgroup|option|p|param|search|section|summary|table|tbody|td|tfoot|th|thead|title|tr|track|ul)';
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public const PARTIAL_ATTRIBUTENAME = '[a-z_:][a-z0-9:._-]*';
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public const PARTIAL_UNQUOTEDVALUE = '[^"\'=<>`\x00-\x20]+';
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public const PARTIAL_SINGLEQUOTEDVALUE = '\'[^\']*\'';
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public const PARTIAL_DOUBLEQUOTEDVALUE = '"[^"]*"';
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public const PARTIAL_ATTRIBUTEVALUE = '(?:' . self::PARTIAL_UNQUOTEDVALUE . '|' . self::PARTIAL_SINGLEQUOTEDVALUE . '|' . self::PARTIAL_DOUBLEQUOTEDVALUE . ')';
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public const PARTIAL_ATTRIBUTEVALUESPEC = '(?:' . '\s*=' . '\s*' . self::PARTIAL_ATTRIBUTEVALUE . ')';
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public const PARTIAL_ATTRIBUTE = '(?:' . '\s+' . self::PARTIAL_ATTRIBUTENAME . self::PARTIAL_ATTRIBUTEVALUESPEC . '?)';
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public const PARTIAL_OPENTAG = '<' . self::PARTIAL_TAGNAME . self::PARTIAL_ATTRIBUTE . '*' . '\s*\/?>';
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public const PARTIAL_CLOSETAG = '<\/' . self::PARTIAL_TAGNAME . '\s*[>]';
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public const PARTIAL_OPENBLOCKTAG = '<' . self::PARTIAL_BLOCKTAGNAME . self::PARTIAL_ATTRIBUTE . '*' . '\s*\/?>';
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public const PARTIAL_CLOSEBLOCKTAG = '<\/' . self::PARTIAL_BLOCKTAGNAME . '\s*[>]';
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public const PARTIAL_HTMLCOMMENT = '<!-->|<!--->|<!--[\s\S]*?-->';
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public const PARTIAL_PROCESSINGINSTRUCTION = '[<][?][\s\S]*?[?][>]';
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public const PARTIAL_DECLARATION = '<![A-Za-z]+' . '[^>]*>';
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public const PARTIAL_CDATA = '<!\[CDATA\[[\s\S]*?]\]>';
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public const PARTIAL_HTMLTAG = '(?:' . self::PARTIAL_OPENTAG . '|' . self::PARTIAL_CLOSETAG . '|' . self::PARTIAL_HTMLCOMMENT . '|' .
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self::PARTIAL_PROCESSINGINSTRUCTION . '|' . self::PARTIAL_DECLARATION . '|' . self::PARTIAL_CDATA . ')';
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public const PARTIAL_HTMLBLOCKOPEN = '<(?:' . self::PARTIAL_BLOCKTAGNAME . '(?:[\s\/>]|$)' . '|' .
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'\/' . self::PARTIAL_BLOCKTAGNAME . '(?:[\s>]|$)' . '|' . '[?!])';
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public const PARTIAL_LINK_TITLE = '^(?:"(' . self::PARTIAL_ESCAPED_CHAR . '|[^"\x00])*+"' .
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'|' . '\'(' . self::PARTIAL_ESCAPED_CHAR . '|[^\'\x00])*+\'' .
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'|' . '\((' . self::PARTIAL_ESCAPED_CHAR . '|[^()\x00])*+\))';
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public const REGEX_PUNCTUATION = '/^[!"#$%&\'()*+,\-.\\/:;<=>?@\\[\\]\\\\^_`{|}~\p{P}\p{S}]/u';
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public const REGEX_UNSAFE_PROTOCOL = '/^javascript:|vbscript:|file:|data:/i';
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public const REGEX_SAFE_DATA_PROTOCOL = '/^data:image\/(?:png|gif|jpeg|webp)/i';
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public const REGEX_NON_SPACE = '/[^ \t\f\v\r\n]/';
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public const REGEX_WHITESPACE_CHAR = '/^[ \t\n\x0b\x0c\x0d]/';
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public const REGEX_UNICODE_WHITESPACE_CHAR = '/^\pZ|\s/u';
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public const REGEX_THEMATIC_BREAK = '/^(?:\*[ \t]*){3,}$|^(?:_[ \t]*){3,}$|^(?:-[ \t]*){3,}$/';
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public const REGEX_LINK_DESTINATION_BRACES = '/^(?:<(?:[^<>\\n\\\\\\x00]|\\\\.)*>)/';
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/**
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* @psalm-pure
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*/
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public static function isEscapable(string $character): bool
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{
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return \preg_match('/' . self::PARTIAL_ESCAPABLE . '/', $character) === 1;
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}
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public static function isWhitespace(string $character): bool
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{
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/** @psalm-suppress InvalidLiteralArgument */
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return $character !== '' && \strpos(" \t\n\x0b\x0c\x0d", $character) !== false;
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}
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/**
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* @psalm-pure
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*/
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public static function isLetter(?string $character): bool
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{
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if ($character === null) {
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return false;
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}
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return \preg_match('/[\pL]/u', $character) === 1;
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}
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/**
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* Attempt to match a regex in string s at offset offset
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*
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* @psalm-param non-empty-string $regex
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*
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* @return int|null Index of match, or null
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*
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* @psalm-pure
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*/
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public static function matchAt(string $regex, string $string, int $offset = 0): ?int
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{
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$matches = [];
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$string = \mb_substr($string, $offset, null, 'UTF-8');
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if (! \preg_match($regex, $string, $matches, \PREG_OFFSET_CAPTURE)) {
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return null;
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}
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// PREG_OFFSET_CAPTURE always returns the byte offset, not the char offset, which is annoying
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$charPos = \mb_strlen(\mb_strcut($string, 0, $matches[0][1], 'UTF-8'), 'UTF-8');
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return $offset + $charPos;
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}
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/**
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* Functional wrapper around preg_match_all which only returns the first set of matches
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*
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* @psalm-param non-empty-string $pattern
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*
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* @return string[]|null
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*
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* @psalm-pure
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*/
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public static function matchFirst(string $pattern, string $subject, int $offset = 0): ?array
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{
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if ($offset !== 0) {
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$subject = \substr($subject, $offset);
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}
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\preg_match_all($pattern, $subject, $matches, \PREG_SET_ORDER);
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if ($matches === []) {
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return null;
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}
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return $matches[0] ?: null;
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}
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/**
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* Replace backslash escapes with literal characters
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*
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* @psalm-pure
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*/
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public static function unescape(string $string): string
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{
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$allEscapedChar = '/\\\\(' . self::PARTIAL_ESCAPABLE . ')/';
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$escaped = \preg_replace($allEscapedChar, '$1', $string);
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\assert(\is_string($escaped));
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return \preg_replace_callback('/' . self::PARTIAL_ENTITY . '/i', static fn ($e) => Html5EntityDecoder::decode($e[0]), $escaped);
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}
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/**
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* @internal
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*
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* @param int $type HTML block type
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*
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* @psalm-param HtmlBlock::TYPE_* $type
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*
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* @phpstan-param HtmlBlock::TYPE_* $type
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*
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* @psalm-return non-empty-string
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*
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* @throws InvalidArgumentException if an invalid type is given
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*
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* @psalm-pure
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*/
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public static function getHtmlBlockOpenRegex(int $type): string
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{
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switch ($type) {
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case HtmlBlock::TYPE_1_CODE_CONTAINER:
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return '/^<(?:script|pre|textarea|style)(?:\s|>|$)/i';
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case HtmlBlock::TYPE_2_COMMENT:
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return '/^<!--/';
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case HtmlBlock::TYPE_3:
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return '/^<[?]/';
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case HtmlBlock::TYPE_4:
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return '/^<![A-Z]/i';
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case HtmlBlock::TYPE_5_CDATA:
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return '/^<!\[CDATA\[/i';
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case HtmlBlock::TYPE_6_BLOCK_ELEMENT:
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return '%^<[/]?(?:address|article|aside|base|basefont|blockquote|body|caption|center|col|colgroup|dd|details|dialog|dir|div|dl|dt|fieldset|figcaption|figure|footer|form|frame|frameset|h[123456]|head|header|hr|html|iframe|legend|li|link|main|menu|menuitem|nav|noframes|ol|optgroup|option|p|param|section|source|summary|table|tbody|td|tfoot|th|thead|title|tr|track|ul)(?:\s|[/]?[>]|$)%i';
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case HtmlBlock::TYPE_7_MISC_ELEMENT:
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return '/^(?:' . self::PARTIAL_OPENTAG . '|' . self::PARTIAL_CLOSETAG . ')\\s*$/i';
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default:
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throw new InvalidArgumentException('Invalid HTML block type');
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}
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}
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/**
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* @internal
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*
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* @param int $type HTML block type
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*
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* @psalm-param HtmlBlock::TYPE_* $type
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*
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* @phpstan-param HtmlBlock::TYPE_* $type
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*
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* @psalm-return non-empty-string
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*
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* @throws InvalidArgumentException if an invalid type is given
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*
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* @psalm-pure
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*/
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public static function getHtmlBlockCloseRegex(int $type): string
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{
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switch ($type) {
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case HtmlBlock::TYPE_1_CODE_CONTAINER:
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return '%<\/(?:script|pre|textarea|style)>%i';
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case HtmlBlock::TYPE_2_COMMENT:
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return '/-->/';
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case HtmlBlock::TYPE_3:
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return '/\?>/';
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case HtmlBlock::TYPE_4:
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return '/>/';
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case HtmlBlock::TYPE_5_CDATA:
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return '/\]\]>/';
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default:
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throw new InvalidArgumentException('Invalid HTML block type');
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}
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}
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/**
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* @psalm-pure
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*/
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public static function isLinkPotentiallyUnsafe(string $url): bool
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{
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return \preg_match(self::REGEX_UNSAFE_PROTOCOL, $url) !== 0 && \preg_match(self::REGEX_SAFE_DATA_PROTOCOL, $url) === 0;
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}
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}
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