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    <h3>Editing: StringHandler.php</h3>
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/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\CssSelector\Parser\Handler;

use Symfony\Component\CssSelector\Exception\InternalErrorException;
use Symfony\Component\CssSelector\Exception\SyntaxErrorException;
use Symfony\Component\CssSelector\Parser\Reader;
use Symfony\Component\CssSelector\Parser\Token;
use Symfony\Component\CssSelector\Parser\Tokenizer\TokenizerEscaping;
use Symfony\Component\CssSelector\Parser\Tokenizer\TokenizerPatterns;
use Symfony\Component\CssSelector\Parser\TokenStream;

/**
 * CSS selector comment handler.
 *
 * This component is a port of the Python cssselect library,
 * which is copyright Ian Bicking, @see https://github.com/SimonSapin/cssselect.
 *
 * @author Jean-François Simon &lt;jeanfrancois.simon@sensiolabs.com&gt;
 *
 * @internal
 */
class StringHandler implements HandlerInterface
{
    private $patterns;
    private $escaping;

    public function __construct(TokenizerPatterns $patterns, TokenizerEscaping $escaping)
    {
        $this-&gt;patterns = $patterns;
        $this-&gt;escaping = $escaping;
    }

    /**
     * {@inheritdoc}
     */
    public function handle(Reader $reader, TokenStream $stream): bool
    {
        $quote = $reader-&gt;getSubstring(1);

        if (!\in_array($quote, [&quot;'&quot;, '&quot;'])) {
            return false;
        }

        $reader-&gt;moveForward(1);
        $match = $reader-&gt;findPattern($this-&gt;patterns-&gt;getQuotedStringPattern($quote));

        if (!$match) {
            throw new InternalErrorException(sprintf('Should have found at least an empty match at %d.', $reader-&gt;getPosition()));
        }

        // check unclosed strings
        if (\strlen($match[0]) === $reader-&gt;getRemainingLength()) {
            throw SyntaxErrorException::unclosedString($reader-&gt;getPosition() - 1);
        }

        // check quotes pairs validity
        if ($quote !== $reader-&gt;getSubstring(1, \strlen($match[0]))) {
            throw SyntaxErrorException::unclosedString($reader-&gt;getPosition() - 1);
        }

        $string = $this-&gt;escaping-&gt;escapeUnicodeAndNewLine($match[0]);
        $stream-&gt;push(new Token(Token::TYPE_STRING, $string, $reader-&gt;getPosition()));
        $reader-&gt;moveForward(\strlen($match[0]) + 1);

        return true;
    }
}
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