wikimedia/mediawiki-core

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includes/libs/Diff/TableDiffFormatter.php

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<?php
/**
 * Portions taken from phpwiki-1.3.3.
 *
 * Copyright © 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 * You may copy this code freely under the conditions of the GPL.
 *
 * 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 DifferenceEngine
 */

namespace Wikimedia\Diff;

use InvalidArgumentException;

/**
 * MediaWiki default table style diff formatter
 * @todo document
 * @newable
 * @ingroup DifferenceEngine
 */
class TableDiffFormatter extends DiffFormatter {

    /**
     * Constants for diff sides. Note: these are also used for context lines.
     */
    private const SIDE_DELETED = 'deleted';
    private const SIDE_ADDED = 'added';
    private const SIDE_CLASSES = [
        self::SIDE_DELETED => 'diff-side-deleted',
        self::SIDE_ADDED => 'diff-side-added'
    ];

    public function __construct() {
        $this->leadingContextLines = 2;
        $this->trailingContextLines = 2;
    }

    /**
     * @param string $msg
     *
     * @return string
     */
    public static function escapeWhiteSpace( $msg ) {
        $msg = preg_replace( '/^ /m', "\u{00A0} ", $msg );
        $msg = preg_replace( '/ $/m', " \u{00A0}", $msg );
        $msg = preg_replace( '/  /', "\u{00A0} ", $msg );

        return $msg;
    }

    /**
     * @param int $xbeg
     * @param int $xlen
     * @param int $ybeg
     * @param int $ylen
     *
     * @return string
     */
    protected function blockHeader( $xbeg, $xlen, $ybeg, $ylen ) {
        // '<!--LINE \d+ -->' get replaced by a localised line number
        // in BaseTextDiffer::localizeLineNumbers
        return $this->rawElement(
            'tr',
            [],
            $this->rawElement(
                'td',
                [ 'colspan' => '2', 'class' => 'diff-lineno', 'id' => 'mw-diff-left-l' . $xbeg ],
                '<!--LINE ' . $xbeg . '-->'
            ) .
            "\n" .
            $this->rawElement(
                'td',
                [ 'colspan' => '2', 'class' => 'diff-lineno' ],
                '<!--LINE ' . $ybeg . '-->'
            )
        ) . "\n";
    }

    /** @inheritDoc */
    protected function startBlock( $header ) {
        $this->writeOutput( $header );
    }

    /** @inheritDoc */
    protected function endBlock() {
    }

    /**
     * @param string[] $lines
     * @param string $prefix
     * @param string $color
     */
    protected function lines( $lines, $prefix = ' ', $color = 'white' ) {
    }

    /**
     * HTML-escape parameter before calling this
     *
     * @param string $line
     *
     * @return string
     */
    protected function addedLine( $line ) {
        return $this->wrapLine( '+', [ 'diff-addedline', $this->getClassForSide( self::SIDE_ADDED ) ], $line );
    }

    /**
     * HTML-escape parameter before calling this
     *
     * @param string $line
     *
     * @return string
     */
    protected function deletedLine( $line ) {
        return $this->wrapLine( '−', [ 'diff-deletedline', $this->getClassForSide( self::SIDE_DELETED ) ], $line );
    }

    /**
     * HTML-escape parameter before calling this
     *
     * @param string $line
     * @param string $side self::SIDE_DELETED or self::SIDE_ADDED
     *
     * @return string
     */
    protected function contextLine( $line, string $side ) {
        return $this->wrapLine( '', [ 'diff-context', $this->getClassForSide( $side ) ], $line );
    }

    /**
     * @param string $marker
     * @param string|string[] $class A single class or a list of classes
     * @param string $line
     *
     * @return string
     */
    protected function wrapLine( $marker, $class, $line ) {
        if ( $line !== '' ) {
            // The <div> wrapper is needed for 'overflow: auto' style to scroll properly
            $line = $this->rawElement( 'div', [], $this->escapeWhiteSpace( $line ) );
        } else {
            $line = '<br>';
        }

        $markerAttrs = [ 'class' => 'diff-marker' ];
        if ( $marker ) {
            $markerAttrs['data-marker'] = $marker;
        }

        if ( is_array( $class ) ) {
            $class = implode( ' ', $class );
        }

        return $this->element( 'td', $markerAttrs ) .
            $this->rawElement( 'td', [ 'class' => $class ], $line );
    }

    /**
     * @param string $side self::SIDE_DELETED or self::SIDE_ADDED
     * @return string
     */
    protected function emptyLine( string $side ) {
        return $this->element( 'td', [ 'colspan' => '2', 'class' => $this->getClassForSide( $side ) ] );
    }

    /**
     * Writes all lines to the output buffer, each enclosed in <tr>.
     *
     * @param string[] $lines
     */
    protected function added( $lines ) {
        foreach ( $lines as $line ) {
            $this->writeOutput(
                $this->rawElement(
                    'tr',
                    [],
                    $this->emptyLine( self::SIDE_DELETED ) .
                    $this->addedLine(
                        $this->element(
                            'ins',
                            [ 'class' => 'diffchange' ],
                            $line
                        )
                    )
                ) .
                "\n"
            );
        }
    }

    /**
     * Writes all lines to the output buffer, each enclosed in <tr>.
     *
     * @param string[] $lines
     */
    protected function deleted( $lines ) {
        foreach ( $lines as $line ) {
            $this->writeOutput(
                $this->rawElement(
                    'tr',
                    [],
                    $this->deletedLine(
                        $this->element(
                            'del',
                            [ 'class' => 'diffchange' ],
                            $line
                        )
                    ) .
                    $this->emptyLine( self::SIDE_ADDED )
                ) .
                "\n"
            );
        }
    }

    /**
     * Writes all lines to the output buffer, each enclosed in <tr>.
     *
     * @param string[] $lines
     */
    protected function context( $lines ) {
        foreach ( $lines as $line ) {
            $this->writeOutput(
                $this->rawElement(
                    'tr',
                    [],
                    $this->contextLine( htmlspecialchars( $line ), self::SIDE_DELETED ) .
                    $this->contextLine( htmlspecialchars( $line ), self::SIDE_ADDED )
                ) .
                "\n"
            );
        }
    }

    /**
     * Writes the two sets of lines to the output buffer, each enclosed in <tr>.
     *
     * @param string[] $orig
     * @param string[] $closing
     */
    protected function changed( $orig, $closing ) {
        $diff = new WordLevelDiff( $orig, $closing );
        $del = $diff->orig();
        $add = $diff->closing();

        # Notice that WordLevelDiff returns HTML-escaped output.
        # Hence, we will be calling addedLine/deletedLine without HTML-escaping.

        $ndel = count( $del );
        $nadd = count( $add );
        $n = max( $ndel, $nadd );
        for ( $i = 0; $i < $n; $i++ ) {
            $delLine = $i < $ndel ? $this->deletedLine( $del[$i] ) : $this->emptyLine( self::SIDE_DELETED );
            $addLine = $i < $nadd ? $this->addedLine( $add[$i] ) : $this->emptyLine( self::SIDE_ADDED );
            $this->writeOutput(
                $this->rawElement(
                    'tr',
                    [],
                    $delLine . $addLine
                ) .
                "\n"
            );
        }
    }

    /**
     * Get a class for the given diff side, or throw if the side is invalid.
     *
     * @param string $side self::SIDE_DELETED or self::SIDE_ADDED
     * @return string
     * @throws InvalidArgumentException
     */
    private function getClassForSide( string $side ): string {
        if ( !isset( self::SIDE_CLASSES[$side] ) ) {
            throw new InvalidArgumentException( "Invalid diff side: $side" );
        }
        return self::SIDE_CLASSES[$side];
    }

    /**
     * Serialize an HTML element, with raw contents.
     *
     * @param string $element
     * @param string[] $attribs
     * @param string $contents The HTML element contents
     * @return string
     */
    private function rawElement( $element, $attribs = [], $contents = '' ) {
        $ret = "<$element";
        foreach ( $attribs as $name => $value ) {
            $ret .= " $name=\"" . htmlspecialchars( $value, ENT_QUOTES ) . '"';
        }
        $ret .= ">$contents</$element>";
        return $ret;
    }

    /**
     * Serialize an HTML element, encoding the text contents.
     *
     * @param string $element
     * @param string[] $attribs
     * @param string $contents The text contents
     * @return string
     */
    private function element( $element, $attribs = [], $contents = '' ) {
        return $this->rawElement( $element, $attribs, htmlspecialchars( $contents, ENT_NOQUOTES ) );
    }
}

/** @deprecated class alias since 1.41 */
class_alias( TableDiffFormatter::class, 'TableDiffFormatter' );