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vendor/symfony/css-selector/XPath/Extension/FunctionExtension.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\XPath\Extension;
+
+use Symfony\Component\CssSelector\Exception\ExpressionErrorException;
+use Symfony\Component\CssSelector\Exception\SyntaxErrorException;
+use Symfony\Component\CssSelector\Node\FunctionNode;
+use Symfony\Component\CssSelector\Parser\Parser;
+use Symfony\Component\CssSelector\XPath\Translator;
+use Symfony\Component\CssSelector\XPath\XPathExpr;
+
+/**
+ * XPath expression translator function extension.
+ *
+ * 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 FunctionExtension extends AbstractExtension
+{
+    public function getFunctionTranslators(): array
+    {
+        return [
+            'nth-child' => $this->translateNthChild(...),
+            'nth-last-child' => $this->translateNthLastChild(...),
+            'nth-of-type' => $this->translateNthOfType(...),
+            'nth-last-of-type' => $this->translateNthLastOfType(...),
+            'contains' => $this->translateContains(...),
+            'lang' => $this->translateLang(...),
+        ];
+    }
+
+    /**
+     * @throws ExpressionErrorException
+     */
+    public function translateNthChild(XPathExpr $xpath, FunctionNode $function, bool $last = false, bool $addNameTest = true): XPathExpr
+    {
+        try {
+            [$a, $b] = Parser::parseSeries($function->getArguments());
+        } catch (SyntaxErrorException $e) {
+            throw new ExpressionErrorException(sprintf('Invalid series: "%s".', implode('", "', $function->getArguments())), 0, $e);
+        }
+
+        $xpath->addStarPrefix();
+        if ($addNameTest) {
+            $xpath->addNameTest();
+        }
+
+        if (0 === $a) {
+            return $xpath->addCondition('position() = '.($last ? 'last() - '.($b - 1) : $b));
+        }
+
+        if ($a < 0) {
+            if ($b < 1) {
+                return $xpath->addCondition('false()');
+            }
+
+            $sign = '<=';
+        } else {
+            $sign = '>=';
+        }
+
+        $expr = 'position()';
+
+        if ($last) {
+            $expr = 'last() - '.$expr;
+            --$b;
+        }
+
+        if (0 !== $b) {
+            $expr .= ' - '.$b;
+        }
+
+        $conditions = [sprintf('%s %s 0', $expr, $sign)];
+
+        if (1 !== $a && -1 !== $a) {
+            $conditions[] = sprintf('(%s) mod %d = 0', $expr, $a);
+        }
+
+        return $xpath->addCondition(implode(' and ', $conditions));
+
+        // todo: handle an+b, odd, even
+        // an+b means every-a, plus b, e.g., 2n+1 means odd
+        // 0n+b means b
+        // n+0 means a=1, i.e., all elements
+        // an means every a elements, i.e., 2n means even
+        // -n means -1n
+        // -1n+6 means elements 6 and previous
+    }
+
+    public function translateNthLastChild(XPathExpr $xpath, FunctionNode $function): XPathExpr
+    {
+        return $this->translateNthChild($xpath, $function, true);
+    }
+
+    public function translateNthOfType(XPathExpr $xpath, FunctionNode $function): XPathExpr
+    {
+        return $this->translateNthChild($xpath, $function, false, false);
+    }
+
+    /**
+     * @throws ExpressionErrorException
+     */
+    public function translateNthLastOfType(XPathExpr $xpath, FunctionNode $function): XPathExpr
+    {
+        if ('*' === $xpath->getElement()) {
+            throw new ExpressionErrorException('"*:nth-of-type()" is not implemented.');
+        }
+
+        return $this->translateNthChild($xpath, $function, true, false);
+    }
+
+    /**
+     * @throws ExpressionErrorException
+     */
+    public function translateContains(XPathExpr $xpath, FunctionNode $function): XPathExpr
+    {
+        $arguments = $function->getArguments();
+        foreach ($arguments as $token) {
+            if (!($token->isString() || $token->isIdentifier())) {
+                throw new ExpressionErrorException('Expected a single string or identifier for :contains(), got '.implode(', ', $arguments));
+            }
+        }
+
+        return $xpath->addCondition(sprintf(
+            'contains(string(.), %s)',
+            Translator::getXpathLiteral($arguments[0]->getValue())
+        ));
+    }
+
+    /**
+     * @throws ExpressionErrorException
+     */
+    public function translateLang(XPathExpr $xpath, FunctionNode $function): XPathExpr
+    {
+        $arguments = $function->getArguments();
+        foreach ($arguments as $token) {
+            if (!($token->isString() || $token->isIdentifier())) {
+                throw new ExpressionErrorException('Expected a single string or identifier for :lang(), got '.implode(', ', $arguments));
+            }
+        }
+
+        return $xpath->addCondition(sprintf(
+            'lang(%s)',
+            Translator::getXpathLiteral($arguments[0]->getValue())
+        ));
+    }
+
+    public function getName(): string
+    {
+        return 'function';
+    }
+}