glastree_on_gitea

vendor/league/commonmark/src/Util/LinkParserHelper.php

@@ -0,0 +1,165 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * Original code based on the CommonMark JS reference parser (https://bitly.com/commonmark-js)
+ *  - (c) John MacFarlane
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace League\CommonMark\Util;
+
+use League\CommonMark\Parser\Cursor;
+
+/**
+ * @psalm-immutable
+ */
+final class LinkParserHelper
+{
+    /**
+     * Attempt to parse link destination
+     *
+     * @return string|null The string, or null if no match
+     */
+    public static function parseLinkDestination(Cursor $cursor): ?string
+    {
+        if ($cursor->getCurrentCharacter() === '<') {
+            return self::parseDestinationBraces($cursor);
+        }
+
+        $destination = self::manuallyParseLinkDestination($cursor);
+        if ($destination === null) {
+            return null;
+        }
+
+        return UrlEncoder::unescapeAndEncode(
+            RegexHelper::unescape($destination)
+        );
+    }
+
+    public static function parseLinkLabel(Cursor $cursor): int
+    {
+        $match = $cursor->match('/^\[(?:[^\\\\\[\]]|\\\\.){0,1000}\]/');
+        if ($match === null) {
+            return 0;
+        }
+
+        $length = \mb_strlen($match, 'UTF-8');
+
+        if ($length > 1001) {
+            return 0;
+        }
+
+        return $length;
+    }
+
+    public static function parsePartialLinkLabel(Cursor $cursor): ?string
+    {
+        return $cursor->match('/^(?:[^\\\\\[\]]++|\\\\.?)*+/');
+    }
+
+    /**
+     * Attempt to parse link title (sans quotes)
+     *
+     * @return string|null The string, or null if no match
+     */
+    public static function parseLinkTitle(Cursor $cursor): ?string
+    {
+        if ($title = $cursor->match('/' . RegexHelper::PARTIAL_LINK_TITLE . '/')) {
+            // Chop off quotes from title and unescape
+            return RegexHelper::unescape(\substr($title, 1, -1));
+        }
+
+        return null;
+    }
+
+    public static function parsePartialLinkTitle(Cursor $cursor, string $endDelimiter): ?string
+    {
+        $endDelimiter = \preg_quote($endDelimiter, '/');
+        $regex        = \sprintf('/(%s|[^%s\x00])*(?:%s)?/', RegexHelper::PARTIAL_ESCAPED_CHAR, $endDelimiter, $endDelimiter);
+        if (($partialTitle = $cursor->match($regex)) === null) {
+            return null;
+        }
+
+        return RegexHelper::unescape($partialTitle);
+    }
+
+    private static function manuallyParseLinkDestination(Cursor $cursor): ?string
+    {
+        $remainder  = $cursor->getRemainder();
+        $openParens = 0;
+        $len        = \strlen($remainder);
+        for ($i = 0; $i < $len; $i++) {
+            $c = $remainder[$i];
+            if ($c === '\\' && $i + 1 < $len && RegexHelper::isEscapable($remainder[$i + 1])) {
+                $i++;
+            } elseif ($c === '(') {
+                $openParens++;
+                // Limit to 32 nested parens for pathological cases
+                if ($openParens > 32) {
+                    return null;
+                }
+            } elseif ($c === ')') {
+                if ($openParens < 1) {
+                    break;
+                }
+
+                $openParens--;
+            } elseif (\ord($c) <= 32 && RegexHelper::isWhitespace($c)) {
+                break;
+            }
+        }
+
+        if ($openParens !== 0) {
+            return null;
+        }
+
+        if ($i === 0 && (! isset($c) || $c !== ')')) {
+            return null;
+        }
+
+        $destination = \substr($remainder, 0, $i);
+        $cursor->advanceBy(\mb_strlen($destination, 'UTF-8'));
+
+        return $destination;
+    }
+
+    /** @var \WeakReference<Cursor>|null */
+    private static ?\WeakReference $lastCursor       = null;
+    private static bool $lastCursorLacksClosingBrace = false;
+
+    private static function parseDestinationBraces(Cursor $cursor): ?string
+    {
+        // Optimization: If we've previously parsed this cursor and returned `null`, we know
+        // that no closing brace exists, so we can skip the regex entirely. This helps avoid
+        // certain pathological cases where the regex engine can take a very long time to
+        // determine that no match exists.
+        if (self::$lastCursor !== null && self::$lastCursor->get() === $cursor) {
+            if (self::$lastCursorLacksClosingBrace) {
+                return null;
+            }
+        } else {
+            self::$lastCursor = \WeakReference::create($cursor);
+        }
+
+        if ($res = $cursor->match(RegexHelper::REGEX_LINK_DESTINATION_BRACES)) {
+            self::$lastCursorLacksClosingBrace = false;
+
+            // Chop off surrounding <..>:
+            return UrlEncoder::unescapeAndEncode(
+                RegexHelper::unescape(\substr($res, 1, -1))
+            );
+        }
+
+        self::$lastCursorLacksClosingBrace = true;
+
+        return null;
+    }
+}