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vendor/symfony/css-selector/Parser/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 array $tokens = [];
+
+    /**
+     * @var Token[]
+     */
+    private array $used = [];
+
+    private int $cursor = 0;
+    private ?Token $peeked;
+    private bool $peeking = false;
+
+    /**
+     * Pushes a token.
+     *
+     * @return $this
+     */
+    public function push(Token $token): static
+    {
+        $this->tokens[] = $token;
+
+        return $this;
+    }
+
+    /**
+     * Freezes stream.
+     *
+     * @return $this
+     */
+    public function freeze(): static
+    {
+        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(): void
+    {
+        $peek = $this->getPeek();
+
+        if ($peek->isWhitespace()) {
+            $this->getNext();
+        }
+    }
+}