TokenStream.php
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<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\CssSelector\Parser;
use Symfony\Component\CssSelector\Exception\InternalErrorException;
use Symfony\Component\CssSelector\Exception\SyntaxErrorException;
/**
* CSS selector token stream.
*
* 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 <jeanfrancois.simon@sensiolabs.com>
*
* @internal
*/
class TokenStream
{
/**
* @var Token[]
*/
private $tokens = [];
/**
* @var Token[]
*/
private $used = [];
/**
* @var int
*/
private $cursor = 0;
/**
* @var Token|null
*/
private $peeked;
/**
* @var bool
*/
private $peeking = false;
/**
* Pushes a token.
*
* @return $this
*/
public function push(Token $token): self
{
$this->tokens[] = $token;
return $this;
}
/**
* Freezes stream.
*
* @return $this
*/
public function freeze(): self
{
return $this;
}
/**
* Returns next token.
*
* @throws InternalErrorException If there is no more token
*/
public function getNext(): Token
{
if ($this->peeking) {
$this->peeking = false;
$this->used[] = $this->peeked;
return $this->peeked;
}
if (!isset($this->tokens[$this->cursor])) {
throw new InternalErrorException('Unexpected token stream end.');
}
return $this->tokens[$this->cursor++];
}
/**
* Returns peeked token.
*/
public function getPeek(): Token
{
if (!$this->peeking) {
$this->peeked = $this->getNext();
$this->peeking = true;
}
return $this->peeked;
}
/**
* Returns used tokens.
*
* @return Token[]
*/
public function getUsed(): array
{
return $this->used;
}
/**
* Returns next identifier token.
*
* @throws SyntaxErrorException If next token is not an identifier
*/
public function getNextIdentifier(): string
{
$next = $this->getNext();
if (!$next->isIdentifier()) {
throw SyntaxErrorException::unexpectedToken('identifier', $next);
}
return $next->getValue();
}
/**
* Returns next identifier or null if star delimiter token is found.
*
* @throws SyntaxErrorException If next token is not an identifier or a star delimiter
*/
public function getNextIdentifierOrStar(): ?string
{
$next = $this->getNext();
if ($next->isIdentifier()) {
return $next->getValue();
}
if ($next->isDelimiter(['*'])) {
return null;
}
throw SyntaxErrorException::unexpectedToken('identifier or "*"', $next);
}
/**
* Skips next whitespace if any.
*/
public function skipWhitespace()
{
$peek = $this->getPeek();
if ($peek->isWhitespace()) {
$this->getNext();
}
}
}