HeadingStartParser.php
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<?php
declare(strict_types=1);
/*
* This file is part of the league/commonmark package.
*
* (c) Colin O'Dell <colinodell@gmail.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace League\CommonMark\Extension\CommonMark\Parser\Block;
use League\CommonMark\Parser\Block\BlockStart;
use League\CommonMark\Parser\Block\BlockStartParserInterface;
use League\CommonMark\Parser\Cursor;
use League\CommonMark\Parser\MarkdownParserStateInterface;
use League\CommonMark\Util\RegexHelper;
class HeadingStartParser implements BlockStartParserInterface
{
public function tryStart(Cursor $cursor, MarkdownParserStateInterface $parserState): ?BlockStart
{
if ($cursor->isIndented() || ! \in_array($cursor->getNextNonSpaceCharacter(), ['#', '-', '='], true)) {
return BlockStart::none();
}
$cursor->advanceToNextNonSpaceOrTab();
if ($atxHeading = self::getAtxHeader($cursor)) {
return BlockStart::of($atxHeading)->at($cursor);
}
$setextHeadingLevel = self::getSetextHeadingLevel($cursor);
if ($setextHeadingLevel > 0) {
$content = $parserState->getParagraphContent();
if ($content !== null) {
$cursor->advanceToEnd();
return BlockStart::of(new HeadingParser($setextHeadingLevel, $content))
->at($cursor)
->replaceActiveBlockParser();
}
}
return BlockStart::none();
}
private static function getAtxHeader(Cursor $cursor): ?HeadingParser
{
$match = RegexHelper::matchFirst('/^#{1,6}(?:[ \t]+|$)/', $cursor->getRemainder());
if (! $match) {
return null;
}
$cursor->advanceToNextNonSpaceOrTab();
$cursor->advanceBy(\strlen($match[0]));
$level = \strlen(\trim($match[0]));
$str = $cursor->getRemainder();
$str = \preg_replace('/^[ \t]*#+[ \t]*$/', '', $str);
\assert(\is_string($str));
$str = \preg_replace('/[ \t]+#+[ \t]*$/', '', $str);
\assert(\is_string($str));
return new HeadingParser($level, $str);
}
private static function getSetextHeadingLevel(Cursor $cursor): int
{
$match = RegexHelper::matchFirst('/^(?:=+|-+)[ \t]*$/', $cursor->getRemainder());
if ($match === null) {
return 0;
}
return $match[0][0] === '=' ? 1 : 2;
}
}