Viewing file:  TableOfContentsGenerator.php (5.92 KB) -rw-r--r--
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<?php
/*
* 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\TableOfContents;
use League\CommonMark\Block\Element\Document;
use League\CommonMark\Block\Element\Heading;
use League\CommonMark\Block\Element\ListBlock;
use League\CommonMark\Block\Element\ListData;
use League\CommonMark\Block\Element\ListItem;
use League\CommonMark\Block\Element\Paragraph;
use League\CommonMark\Exception\InvalidOptionException;
use League\CommonMark\Extension\HeadingPermalink\HeadingPermalink;
use League\CommonMark\Extension\TableOfContents\Node\TableOfContents;
use League\CommonMark\Extension\TableOfContents\Normalizer\AsIsNormalizerStrategy;
use League\CommonMark\Extension\TableOfContents\Normalizer\FlatNormalizerStrategy;
use League\CommonMark\Extension\TableOfContents\Normalizer\NormalizerStrategyInterface;
use League\CommonMark\Extension\TableOfContents\Normalizer\RelativeNormalizerStrategy;
use League\CommonMark\Inline\Element\AbstractStringContainer;
use League\CommonMark\Inline\Element\Link;
final class TableOfContentsGenerator implements TableOfContentsGeneratorInterface
{
public const STYLE_BULLET = ListBlock::TYPE_BULLET;
public const STYLE_ORDERED = ListBlock::TYPE_ORDERED;
public const NORMALIZE_DISABLED = 'as-is';
public const NORMALIZE_RELATIVE = 'relative';
public const NORMALIZE_FLAT = 'flat';
/** @var string */
private $style;
/** @var string */
private $normalizationStrategy;
/** @var int */
private $minHeadingLevel;
/** @var int */
private $maxHeadingLevel;
public function __construct(string $style, string $normalizationStrategy, int $minHeadingLevel, int $maxHeadingLevel)
{
$this->style = $style;
$this->normalizationStrategy = $normalizationStrategy;
$this->minHeadingLevel = $minHeadingLevel;
$this->maxHeadingLevel = $maxHeadingLevel;
}
public function generate(Document $document): ?TableOfContents
{
$toc = $this->createToc($document);
$normalizer = $this->getNormalizer($toc);
$firstHeading = null;
foreach ($this->getHeadingLinks($document) as $headingLink) {
$heading = $headingLink->parent();
// Make sure this is actually tied to a heading
if (!$heading instanceof Heading) {
continue;
}
// Skip any headings outside the configured min/max levels
if ($heading->getLevel() < $this->minHeadingLevel || $heading->getLevel() > $this->maxHeadingLevel) {
continue;
}
// Keep track of the first heading we see - we might need this later
$firstHeading = $firstHeading ?? $heading;
// Keep track of the start and end lines
$toc->setStartLine($firstHeading->getStartLine());
$toc->setEndLine($heading->getEndLine());
// Create the new link
$link = new Link('#' . $headingLink->getSlug(), self::getHeadingText($heading));
$paragraph = new Paragraph();
$paragraph->setStartLine($heading->getStartLine());
$paragraph->setEndLine($heading->getEndLine());
$paragraph->appendChild($link);
$listItem = new ListItem($toc->getListData());
$listItem->setStartLine($heading->getStartLine());
$listItem->setEndLine($heading->getEndLine());
$listItem->appendChild($paragraph);
// Add it to the correct place
$normalizer->addItem($heading->getLevel(), $listItem);
}
// Don't add the TOC if no headings were present
if (!$toc->hasChildren() || $firstHeading === null) {
return null;
}
return $toc;
}
private function createToc(Document $document): TableOfContents
{
$listData = new ListData();
if ($this->style === self::STYLE_BULLET) {
$listData->type = ListBlock::TYPE_BULLET;
} elseif ($this->style === self::STYLE_ORDERED) {
$listData->type = ListBlock::TYPE_ORDERED;
} else {
throw new InvalidOptionException(\sprintf('Invalid table of contents list style "%s"', $this->style));
}
$toc = new TableOfContents($listData);
$toc->setStartLine($document->getStartLine());
$toc->setEndLine($document->getEndLine());
return $toc;
}
/**
* @param Document $document
*
* @return iterable<HeadingPermalink>
*/
private function getHeadingLinks(Document $document)
{
$walker = $document->walker();
while ($event = $walker->next()) {
if ($event->isEntering() && ($node = $event->getNode()) instanceof HeadingPermalink) {
yield $node;
}
}
}
private function getNormalizer(TableOfContents $toc): NormalizerStrategyInterface
{
switch ($this->normalizationStrategy) {
case self::NORMALIZE_DISABLED:
return new AsIsNormalizerStrategy($toc);
case self::NORMALIZE_RELATIVE:
return new RelativeNormalizerStrategy($toc);
case self::NORMALIZE_FLAT:
return new FlatNormalizerStrategy($toc);
default:
throw new InvalidOptionException(\sprintf('Invalid table of contents normalization strategy "%s"', $this->normalizationStrategy));
}
}
/**
* @return string
*/
private static function getHeadingText(Heading $heading)
{
$text = '';
$walker = $heading->walker();
while ($event = $walker->next()) {
if ($event->isEntering() && ($child = $event->getNode()) instanceof AbstractStringContainer) {
$text .= $child->getContent();
}
}
return $text;
}
}
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