1 files changed, 149 insertions, 0 deletions
diff --git a/vendor/league/commonmark/src/Extension/TableOfContents/TableOfContentsGenerator.php b/vendor/league/commonmark/src/Extension/TableOfContents/TableOfContentsGenerator.php
new file mode 100644
index 0000000000..ff767348b5
--- /dev/null
+++ b/vendor/league/commonmark/src/Extension/TableOfContents/TableOfContentsGenerator.php
@@ -0,0 +1,149 @@
+<?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\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();
+
+        $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(), $heading->getStringContent());
+            $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(): 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"', $this->style));
+        }
+
+        return new TableOfContents($listData);
+    }
+
+    /**
+     * @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));
+        }
+    }
+}