pokemon-showdown-client/lib/css-sanitizer/Wikimedia/CSS/Grammar/Juxtaposition.php
2023-06-16 11:33:53 -07:00

118 lines
3.5 KiB
PHP

<?php
/**
* @file
* @license https://opensource.org/licenses/Apache-2.0 Apache-2.0
*/
namespace Wikimedia\CSS\Grammar;
use Iterator;
use Wikimedia\CSS\Objects\ComponentValueList;
use Wikimedia\CSS\Objects\Token;
use Wikimedia\CSS\Util;
/**
* Matcher that groups other matchers (juxtaposition)
* @see https://www.w3.org/TR/2019/CR-css-values-3-20190606/#component-combinators
* @see https://www.w3.org/TR/2019/CR-css-values-3-20190606/#comb-comma
*/
class Juxtaposition extends Matcher {
/** @var Matcher[] */
protected $matchers;
/** @var bool Whether non-empty matches are comma-separated */
protected $commas;
/**
* @param Matcher[] $matchers
* @param bool $commas Whether matches are comma-separated
*/
public function __construct( array $matchers, $commas = false ) {
Util::assertAllInstanceOf( $matchers, Matcher::class, '$matchers' );
$this->matchers = $matchers;
$this->commas = (bool)$commas;
}
/** @inheritDoc */
protected function generateMatches( ComponentValueList $values, $start, array $options ) {
$used = [];
// Match each of our matchers in turn, pushing each one onto a stack as
// we process it and popping a match once it's exhausted.
$stack = [
[
new GrammarMatch( $values, $start, 0 ),
$start,
$this->matchers[0]->generateMatches( $values, $start, $options ),
false
]
];
do {
/** @var $lastEnd int */
/** @var $iter Iterator<GrammarMatch> */
/** @var $needEmpty bool */
[ , $lastEnd, $iter, $needEmpty ] = $stack[count( $stack ) - 1];
// If the top of the stack has no more matches, pop it and loop.
if ( !$iter->valid() ) {
array_pop( $stack );
continue;
}
// Find the next match for the current top of the stack.
$match = $iter->current();
$iter->next();
// In some cases, we can only match if the rest of the pattern
// is empty. If we're in that situation, ignore all non-empty
// matches.
if ( $needEmpty && $match->getLength() !== 0 ) {
continue;
}
$thisEnd = $nextFrom = $match->getNext();
// Dealing with commas is a bit tricky. There are three cases:
// 1. If the current match is empty, don't look for a following
// comma now and reset $thisEnd to $lastEnd.
// 2. If there is a comma following, update $nextFrom to be after
// the comma.
// 3. If there's no comma following, every subsequent Matcher must
// be empty in order for the group as a whole to match, so set
// the flag.
// Unlike '#', this doesn't specify skipping whitespace around the
// commas if the production isn't already skipping whitespace.
if ( $this->commas ) {
if ( $match->getLength() === 0 ) {
$thisEnd = $lastEnd;
} elseif ( isset( $values[$nextFrom] ) && $values[$nextFrom] instanceof Token &&
// @phan-suppress-next-line PhanNonClassMethodCall False positive
$values[$nextFrom]->type() === Token::T_COMMA
) {
$nextFrom = $this->next( $values, $nextFrom, $options );
} else {
$needEmpty = true;
}
}
// If we ran out of Matchers, yield the final position. Otherwise,
// push the next matcher onto the stack.
if ( count( $stack ) >= count( $this->matchers ) ) {
$newMatch = $this->makeMatch( $values, $start, $thisEnd, $match, $stack );
$mid = $newMatch->getUniqueID();
if ( !isset( $used[$mid] ) ) {
$used[$mid] = 1;
yield $newMatch;
}
} else {
$stack[] = [
$match,
$thisEnd,
$this->matchers[count( $stack )]->generateMatches( $values, $nextFrom, $options ),
$needEmpty
];
}
} while ( $stack );
}
}