arthurkushman / querypath

src/CSS/DOMTraverser/PseudoClass.php

<?php
/**
 * @file
 *
 * PseudoClass class.
 *
 * This is the first pass in an experiment to break PseudoClass handling
 * out of the normal traversal. Eventually, this should become a
 * top-level pluggable registry that will allow custom pseudoclasses.
 * For now, though, we just handle the core pseudoclasses.
 */

namespace QueryPath\CSS\DOMTraverser;

use \QueryPath\CSS\NotImplementedException;
use \QueryPath\CSS\EventHandler;
use QueryPath\CSS\ParseException;

/**
 *  The PseudoClass handler.
 *
 */
class PseudoClass
{

    /**
     * Tests whether the given element matches the given pseudoclass.
     *
     * @param string $pseudoclass
     *   The string name of the pseudoclass
     * @param resource $node
     *   The DOMNode to be tested.
     * @param resource $scope
     *   The DOMElement that is the active root for this node.
     * @param mixed $value
     *   The optional value string provided with this class. This is
     *   used, for example, in an+b psuedoclasses.
     * @return bool
     * @throws NotImplementedException
     * @throws \QueryPath\CSS\ParseException
     * @retval boolean
     *   TRUE if the node matches, FALSE otherwise.
     */
    public function elementMatches($pseudoclass, $node, $scope, $value = NULL)
    {
        $name = strtolower($pseudoclass);
        // Need to handle known pseudoclasses.
        switch ($name) {
            case 'current':
            case 'past':
            case 'future':
            case 'visited':
            case 'hover':
            case 'active':
            case 'focus':
            case 'animated': //  Last 3 are from jQuery
            case 'visible':
            case 'hidden':
                // These require a UA, which we don't have.
            case 'valid':
            case 'invalid':
            case 'required':
            case 'optional':
            case 'read-only':
            case 'read-write':
                // Since we don't know how to validate elements,
                // we can't supply these.
            case 'dir':
                // FIXME: I don't know how to get directionality info.
            case 'nth-column':
            case 'nth-last-column':
                // We don't know what a column is in most documents.
                // FIXME: Can we do this for HTML?
            case 'target':
                // This requires a location URL, which we don't have.
                return false;
            case 'indeterminate':
                // Because sometimes screwing with people is fun.
                return (boolean)mt_rand(0, 1);
            case 'lang':
                // No value = exception.
                if (!isset($value)) {
                    throw new NotImplementedException(':lang() requires a value.');
                }

                return $this->lang($node, $value);
            case 'any-link':
                return Util::matchesAttribute($node, 'href')
                    || Util::matchesAttribute($node, 'src')
                    || Util::matchesAttribute($node, 'link');
            case 'link':
                return Util::matchesAttribute($node, 'href');
            case 'local-link':
                return $this->isLocalLink($node);
            case 'root':
                return $node->isSameNode($node->ownerDocument->documentElement);

            // CSS 4 declares the :scope pseudo-class, which describes what was
            // the :x-root QueryPath extension.
            case 'x-root':
            case 'x-reset':
            case 'scope':
                return $node->isSameNode($scope);
            // NON-STANDARD extensions for simple support of even and odd. These
            // are supported by jQuery, FF, and other user agents.
            case 'even':
                return $this->isNthChild($node, 'even');
            case 'odd':
                return $this->isNthChild($node, 'odd');
            case 'nth-child':
                return $this->isNthChild($node, $value);
            case 'nth-last-child':
                return $this->isNthChild($node, $value, true);
            case 'nth-of-type':
                return $this->isNthChild($node, $value, false, true);
            case 'nth-last-of-type':
                return $this->isNthChild($node, $value, true, true);
            case 'first-of-type':
                return $this->isFirstOfType($node);
            case 'last-of-type':
                return $this->isLastOfType($node);
            case 'only-of-type':
                return $this->isFirstOfType($node) && $this->isLastOfType($node);

            // Additional pseudo-classes defined in jQuery:
            case 'lt':
                // I'm treating this as "less than or equal to".
                $rule = sprintf('-n + %d', (int)$value);

                // $rule = '-n+15';
                return $this->isNthChild($node, $rule);
            case 'gt':
                // I'm treating this as "greater than"
                // return $this->nodePositionFromEnd($node) > (int) $value;
                return $this->nodePositionFromStart($node) > (int)$value;
            case 'nth':
            case 'eq':
                $rule = (int)$value;

                return $this->isNthChild($node, $rule);
            case 'first':
                return $this->isNthChild($node, 1);
            case 'first-child':
                return $this->isFirst($node);
            case 'last':
            case 'last-child':
                return $this->isLast($node);
            case 'only-child':
                return $this->isFirst($node) && $this->isLast($node);
            case 'empty':
                return $this->isEmpty($node);
            case 'parent':
                return !$this->isEmpty($node);

            case 'enabled':
            case 'disabled':
            case 'checked':
                return Util::matchesAttribute($node, $name);
            case 'text':
            case 'radio':
            case 'checkbox':
            case 'file':
            case 'password':
            case 'submit':
            case 'image':
            case 'reset':
            case 'button':
                return Util::matchesAttribute($node, 'type', $name);

            case 'header':
                return $this->header($node);
            case 'has':
            case 'matches':
                return $this->has($node, $value);
                break;

break is not strictly necessary here and could be removed.

            case 'not':
                if (empty($value)) {
                    throw new ParseException(':not() requires a value.');
                }

                return $this->isNot($node, $value);
            // Contains == text matches.
            // In QP 2.1, this was changed.
            case 'contains':
                return $this->contains($node, $value);
            // Since QP 2.1
            case 'contains-exactly':
                return $this->containsExactly($node, $value);
            default:
                throw new ParseException('Unknown Pseudo-Class: ' . $name);
        }
    }

    /**
     * Pseudo-class handler for :lang
     *
     * Note that this does not implement the spec in its entirety because we do
     * not presume to "know the language" of the document. If anyone is interested
     * in making this more intelligent, please do so.
     */
    protected function lang($node, $value)
    {
        // TODO: This checks for cases where an explicit language is
        // set. The spec seems to indicate that an element should inherit
        // language from the parent... but this is unclear.
        $operator = (strpos($value, '-') !== false) ? EventHandler::IS_EXACTLY : EventHandler::CONTAINS_WITH_HYPHEN;

        $match = true;

The assignment to $match is dead and can be removed.

        foreach ($node->attributes as $attrNode) {
            if ($attrNode->localName === 'lang') {

                if ($attrNode->nodeName === $attrNode->localName) {
                    // fprintf(STDOUT, "%s in NS %s\n", $attrNode->name, $attrNode->nodeName);
                    return Util::matchesAttribute($node, 'lang', $value, $operator);
                }

                $nsuri = $attrNode->namespaceURI;
                // fprintf(STDOUT, "%s in NS %s\n", $attrNode->name, $nsuri);
                return Util::matchesAttributeNS($node, 'lang', $nsuri, $value, $operator);
            }
        }

        return false;
    }

    /**
     * Provides jQuery pseudoclass ':header'.
     *
     * @param $node
     * @return bool
     */
    protected function header($node): bool
    {
        return preg_match('/^h[1-9]$/i', $node->tagName) === 1;
    }

    /**
     * Provides pseudoclass :empty.
     */
    protected function isEmpty($node): bool
    {
        foreach ($node->childNodes as $kid) {
            // We don't want to count PIs and comments. From the spec, it
            // appears that CDATA is also not counted.
            if ($kid->nodeType === XML_ELEMENT_NODE || $kid->nodeType === XML_TEXT_NODE) {
                // As soon as we hit a FALSE, return.
                return false;
            }
        }

        return true;
    }

    /**
     * Provides jQuery pseudoclass :first.
     *
     * @todo
     *   This can be replaced by isNthChild().
     */
    protected function isFirst($node): bool
    {
        while (isset($node->previousSibling)) {
            $node = $node->previousSibling;
            if ($node->nodeType === XML_ELEMENT_NODE) {
                return false;
            }
        }

        return true;
    }

    /**
     * Fast version of first-of-type.
     */
    protected function isFirstOfType($node)
    {
        $type = $node->tagName;
        while (isset($node->previousSibling)) {
            $node = $node->previousSibling;
            if ($node->nodeType === XML_ELEMENT_NODE && $node->tagName === $type) {
                return false;
            }
        }

        return true;
    }

    /**
     * Fast version of jQuery :last.
     */
    protected function isLast($node)
    {
        while (isset($node->nextSibling)) {
            $node = $node->nextSibling;
            if ($node->nodeType === XML_ELEMENT_NODE) {
                return false;
            }
        }

        return true;
    }

    /**
     * Provides last-of-type.
     */
    protected function isLastOfType($node)
    {
        $type = $node->tagName;
        while (isset($node->nextSibling)) {
            $node = $node->nextSibling;
            if ($node->nodeType === XML_ELEMENT_NODE && $node->tagName === $type) {
                return false;
            }
        }

        return true;
    }

    /**
     * Provides :contains() as the original spec called for.
     *
     * This is an INEXACT match.
     */
    protected function contains($node, $value): bool
    {
        $text = $node->textContent;
        $value = Util::removeQuotes($value);

        return isset($text) && (stripos($text, $value) !== false);
    }

    /**
     * Provides :contains-exactly QueryPath pseudoclass.
     *
     * This is an EXACT match.
     */
    protected function containsExactly($node, $value): bool
    {
        $text = $node->textContent;
        $value = Util::removeQuotes($value);

        return isset($text) && $text == $value;
    }

    /**
     * Provides :has pseudoclass.
     *
     * @throws ParseException
     */
    protected function has($node, $selector): bool
    {
        $splos = new \SPLObjectStorage();
        $splos->attach($node);
        $traverser = new \QueryPath\CSS\DOMTraverser($splos, true);
        $results = $traverser->find($selector)->matches();

        return count($results) > 0;
    }

    /**
     * Provides :not pseudoclass.
     *
     * @throws ParseException
     */
    protected function isNot($node, $selector): bool
    {
        return !$this->has($node, $selector);
    }

    /**
     * Get the relative position of a node in its sibling set.
     */
    protected function nodePositionFromStart($node, $byType = false): int
    {
        $i = 1;
        $tag = $node->tagName;
        while (isset($node->previousSibling)) {
            $node = $node->previousSibling;
            if ($node->nodeType === XML_ELEMENT_NODE && (!$byType || $node->tagName === $tag)) {
                ++$i;
            }
        }

        return $i;
    }

    /**
     * Get the relative position of a node in its sibling set.
     *
     * @param $node
     * @param bool $byType
     * @return int
     */
    protected function nodePositionFromEnd($node, $byType = false): int
    {
        $i = 1;
        $tag = $node->tagName;
        while (isset($node->nextSibling)) {
            $node = $node->nextSibling;
            if ($node->nodeType === XML_ELEMENT_NODE && (!$byType || $node->tagName === $tag)) {
                ++$i;
            }
        }

        return $i;
    }

    /**
     * Provides functionality for all "An+B" rules.
     * Provides nth-child and also the functionality required for:
     *
     *- nth-last-child
     *- even
     *- odd
     *- first
     *- last
     *- eq
     *- nth
     *- nth-of-type
     *- first-of-type
     *- last-of-type
     *- nth-last-of-type
     *
     * See also QueryPath::CSS::DOMTraverser::Util::parseAnB().
     *
     * @param $node
     * @param $value
     * @param bool $reverse
     * @param bool $byType
     * @return bool
     */
    protected function isNthChild($node, $value, $reverse = false, $byType = false): bool
    {
        list($groupSize, $elementInGroup) = Util::parseAnB($value);
        $parent = $node->parentNode;
        if (empty($parent)
            || ($groupSize === 0 && $elementInGroup === 0)
            || ($groupSize > 0 && $elementInGroup > $groupSize)
        ) {
            return false;
        }

        // First we need to find the position of $node in other elements.
        if ($reverse) {
            $pos = $this->nodePositionFromEnd($node, $byType);
        } else {
            $pos = $this->nodePositionFromStart($node, $byType);
        }

        // If group size is 0, we just check to see if this
        // is the nth element:
        if ($groupSize === 0) {
            return $pos === $elementInGroup;
        }

        // Next, we normalize $elementInGroup
        if ($elementInGroup < 0) {
            $elementInGroup = $groupSize + $elementInGroup;
        }
        $prod = ($pos - $elementInGroup) / $groupSize;

        return is_int($prod) && $prod >= 0;
    }

    protected function isLocalLink($node): bool
    {
        if (!$node->hasAttribute('href')) {
            return false;
        }
        $url = $node->getAttribute('href');
        $scheme = parse_url($url, PHP_URL_SCHEME);

        return empty($scheme) || $scheme === 'file';
    }

}