wikimedia/mediawiki-core

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includes/parser/StripState.php

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<?php
/**
 * Holder for stripped items when parsing wiki markup.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Parser
 */

use MediaWiki\Parser\Parser;

/**
 * @todo document, briefly.
 * @newable
 * @ingroup Parser
 */
class StripState {
    protected $data;
    protected $regex;

    protected $parser;

    protected $circularRefGuard;
    protected $depth = 0;
    protected $highestDepth = 0;
    protected $expandSize = 0;

    protected $depthLimit = 20;
    protected $sizeLimit = 5_000_000;

    /**
     * @stable to call
     *
     * @param Parser|null $parser
     * @param array $options
     */
    public function __construct( Parser $parser = null, $options = [] ) {
        $this->data = [
            'nowiki' => [],
            'general' => []
        ];
        $this->regex = '/' . Parser::MARKER_PREFIX . "([^\x7f<>&'\"]+)" . Parser::MARKER_SUFFIX . '/';
        $this->circularRefGuard = [];
        $this->parser = $parser;

        if ( isset( $options['depthLimit'] ) ) {
            $this->depthLimit = $options['depthLimit'];
        }
        if ( isset( $options['sizeLimit'] ) ) {
            $this->sizeLimit = $options['sizeLimit'];
        }
    }

    /**
     * Add a nowiki strip item
     * @param string $marker
     * @param string|Closure $value
     */
    public function addNoWiki( $marker, $value ) {
        $this->addItem( 'nowiki', $marker, $value );
    }

    /**
     * @param string $marker
     * @param string|Closure $value
     */
    public function addGeneral( $marker, $value ) {
        $this->addItem( 'general', $marker, $value );
    }

    /**
     * @param string $type
     * @param-taint $type none
     * @param string $marker
     * @param-taint $marker none
     * @param string|Closure $value
     * @param-taint $value exec_html
     */
    protected function addItem( $type, $marker, $value ) {
        if ( !preg_match( $this->regex, $marker, $m ) ) {
            throw new InvalidArgumentException( "Invalid marker: $marker" );
        }

        $this->data[$type][$m[1]] = $value;
    }

    /**
     * @param string $text
     * @return mixed
     */
    public function unstripGeneral( $text ) {
        return $this->unstripType( 'general', $text );
    }

    /**
     * @param string $text
     * @return mixed
     */
    public function unstripNoWiki( $text ) {
        return $this->unstripType( 'nowiki', $text );
    }

    /**
     * @param string $text
     * @param callable $callback
     * @return string
     */
    public function replaceNoWikis( string $text, callable $callback ): string {
        // Shortcut
        if ( !count( $this->data['nowiki'] ) ) {
            return $text;
        }

        $callback = function ( $m ) use ( $callback ) {
            $marker = $m[1];
            if ( isset( $this->data['nowiki'][$marker] ) ) {
                $value = $this->data['nowiki'][$marker];
                if ( $value instanceof Closure ) {
                    $value = $value();
                }

                $this->expandSize += strlen( $value );
                if ( $this->expandSize > $this->sizeLimit ) {
                    return $this->getLimitationWarning( 'unstrip-size', $this->sizeLimit );
                }

                return call_user_func( $callback, $value );
            } else {
                return $m[0];
            }
        };

        return preg_replace_callback( $this->regex, $callback, $text );
    }

    /**
     * @param string $text
     * @return mixed
     */
    public function unstripBoth( $text ) {
        $text = $this->unstripType( 'general', $text );
        $text = $this->unstripType( 'nowiki', $text );
        return $text;
    }

    /**
     * @param string $type
     * @param string $text
     * @return mixed
     */
    protected function unstripType( $type, $text ) {
        // Shortcut
        if ( !count( $this->data[$type] ) ) {
            return $text;
        }

        $callback = function ( $m ) use ( $type ) {
            $marker = $m[1];
            if ( isset( $this->data[$type][$marker] ) ) {
                if ( isset( $this->circularRefGuard[$marker] ) ) {
                    return $this->getWarning( 'parser-unstrip-loop-warning' );
                }

                if ( $this->depth > $this->highestDepth ) {
                    $this->highestDepth = $this->depth;
                }
                if ( $this->depth >= $this->depthLimit ) {
                    return $this->getLimitationWarning( 'unstrip-depth', $this->depthLimit );
                }

                $value = $this->data[$type][$marker];
                if ( $value instanceof Closure ) {
                    $value = $value();
                }

                $this->expandSize += strlen( $value );
                if ( $this->expandSize > $this->sizeLimit ) {
                    return $this->getLimitationWarning( 'unstrip-size', $this->sizeLimit );
                }

                $this->circularRefGuard[$marker] = true;
                $this->depth++;
                $ret = $this->unstripType( $type, $value );
                $this->depth--;
                unset( $this->circularRefGuard[$marker] );

                return $ret;
            } else {
                return $m[0];
            }
        };

        $text = preg_replace_callback( $this->regex, $callback, $text );
        return $text;
    }

    /**
     * Get warning HTML and register a limitation warning with the parser
     *
     * @param string $type
     * @param int|string $max
     * @return string
     */
    private function getLimitationWarning( $type, $max = '' ) {
        if ( $this->parser ) {
            $this->parser->limitationWarn( $type, $max );
        }
        return $this->getWarning( "$type-warning", $max );
    }

    /**
     * Get warning HTML
     *
     * @param string $message
     * @param int|string $max
     * @return string
     */
    private function getWarning( $message, $max = '' ) {
        return '<span class="error">' .
            wfMessage( $message )
                ->numParams( $max )->inContentLanguage()->text() .
            '</span>';
    }

    /**
     * Get an array of parameters to pass to ParserOutput::setLimitReportData()
     *
     * @internal Should only be called by Parser
     * @return array
     */
    public function getLimitReport() {
        return [
            [ 'limitreport-unstrip-depth',
                [
                    $this->highestDepth,
                    $this->depthLimit
                ],
            ],
            [ 'limitreport-unstrip-size',
                [
                    $this->expandSize,
                    $this->sizeLimit
                ],
            ]
        ];
    }

    /**
     * Remove any strip markers found in the given text.
     *
     * @param string $text
     * @return string
     */
    public function killMarkers( $text ) {
        return preg_replace( $this->regex, '', $text );
    }
}