SvgHandler.php

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<?php
use MediaWiki\Shell\Shell;
use Wikimedia\ScopedCallback;

class SvgHandler extends ImageHandler {
    const SVG_METADATA_VERSION = 2;

    private static $metaConversion = [
        'originalwidth' => 'ImageWidth',
        'originalheight' => 'ImageLength',
        'description' => 'ImageDescription',
        'title' => 'ObjectName',
    ];

    public function isEnabled() {
        global $wgSVGConverters, $wgSVGConverter;
        if ( !isset( $wgSVGConverters[$wgSVGConverter] ) ) {
            wfDebug( "\$wgSVGConverter is invalid, disabling SVG rendering.\n" );

            return false;
        } else {
            return true;
        }
    }

    public function mustRender( $file ) {
        return true;
    }

    function isVectorized( $file ) {
        return true;
    }

    function isAnimatedImage( $file ) {
        # @todo Detect animated SVGs
        $metadata = $file->getMetadata();
        if ( $metadata ) {
            $metadata = $this->unpackMetadata( $metadata );
            if ( isset( $metadata['animated'] ) ) {
                return $metadata['animated'];
            }
        }

        return false;
    }

    public function getAvailableLanguages( File $file ) {
        $metadata = $file->getMetadata();
        $langList = [];
        if ( $metadata ) {
            $metadata = $this->unpackMetadata( $metadata );
            if ( isset( $metadata['translations'] ) ) {
                foreach ( $metadata['translations'] as $lang => $langType ) {
                    if ( $langType === SVGReader::LANG_FULL_MATCH ) {
                        $langList[] = strtolower( $lang );
                    }
                }
            }
        }
        return array_unique( $langList );
    }

    public function getMatchedLanguage( $userPreferredLanguage, array $svgLanguages ) {
        foreach ( $svgLanguages as $svgLang ) {
            if ( strcasecmp( $svgLang, $userPreferredLanguage ) === 0 ) {
                return $svgLang;
            }
            $trimmedSvgLang = $svgLang;
            while ( strpos( $trimmedSvgLang, '-' ) !== false ) {
                $trimmedSvgLang = substr( $trimmedSvgLang, 0, strrpos( $trimmedSvgLang, '-' ) );
                if ( strcasecmp( $trimmedSvgLang, $userPreferredLanguage ) === 0 ) {
                    return $svgLang;
                }
            }
        }
        return null;
    }

    protected function getLanguageFromParams( array $params ) {
        return $params['lang'] ?? $params['targetlang'] ?? 'en';
    }

    public function getDefaultRenderLanguage( File $file ) {
        return 'en';
    }

    function canAnimateThumbnail( $file ) {
        return false;
    }

    public function normaliseParams( $image, &$params ) {
        if ( parent::normaliseParams( $image, $params ) ) {
            $params = $this->normaliseParamsInternal( $image, $params );
            return true;
        }

        return false;
    }

    protected function normaliseParamsInternal( $image, $params ) {
        global $wgSVGMaxSize;

        # Don't make an image bigger than wgMaxSVGSize on the smaller side
        if ( $params['physicalWidth'] <= $params['physicalHeight'] ) {
            if ( $params['physicalWidth'] > $wgSVGMaxSize ) {
                $srcWidth = $image->getWidth( $params['page'] );
                $srcHeight = $image->getHeight( $params['page'] );
                $params['physicalWidth'] = $wgSVGMaxSize;
                $params['physicalHeight'] = File::scaleHeight( $srcWidth, $srcHeight, $wgSVGMaxSize );
            }
        } elseif ( $params['physicalHeight'] > $wgSVGMaxSize ) {
            $srcWidth = $image->getWidth( $params['page'] );
            $srcHeight = $image->getHeight( $params['page'] );
            $params['physicalWidth'] = File::scaleHeight( $srcHeight, $srcWidth, $wgSVGMaxSize );
            $params['physicalHeight'] = $wgSVGMaxSize;
        }
        // To prevent the proliferation of thumbnails in languages not present in SVGs, unless
        // explicitly forced by user.
        if ( isset( $params['targetlang'] ) && !$image->getMatchedLanguage( $params['targetlang'] ) ) {
            unset( $params['targetlang'] );
        }

        return $params;
    }

    function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
        if ( !$this->normaliseParams( $image, $params ) ) {
            return new TransformParameterError( $params );
        }
        $clientWidth = $params['width'];
        $clientHeight = $params['height'];
        $physicalWidth = $params['physicalWidth'];
        $physicalHeight = $params['physicalHeight'];
        $lang = $this->getLanguageFromParams( $params );

        if ( $flags & self::TRANSFORM_LATER ) {
            return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
        }

        $metadata = $this->unpackMetadata( $image->getMetadata() );
        if ( isset( $metadata['error'] ) ) { // sanity check
            $err = wfMessage( 'svg-long-error', $metadata['error']['message'] );

            return new MediaTransformError( 'thumbnail_error', $clientWidth, $clientHeight, $err );
        }

        if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
            return new MediaTransformError( 'thumbnail_error', $clientWidth, $clientHeight,
                wfMessage( 'thumbnail_dest_directory' ) );
        }

        $srcPath = $image->getLocalRefPath();
        if ( $srcPath === false ) { // Failed to get local copy
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not get local copy of "%s"',
                    wfHostname(), $image->getName() ) );

            return new MediaTransformError( 'thumbnail_error',
                $params['width'], $params['height'],
                wfMessage( 'filemissing' )
            );
        }

        // Make a temp dir with a symlink to the local copy in it.
        // This plays well with rsvg-convert policy for external entities.
        // https://git.gnome.org/browse/librsvg/commit/?id=f01aded72c38f0e18bc7ff67dee800e380251c8e
        $tmpDir = wfTempDir() . '/svg_' . wfRandomString( 24 );
        $lnPath = "$tmpDir/" . basename( $srcPath );
        $ok = mkdir( $tmpDir, 0771 );
        if ( !$ok ) {
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not create temporary directory %s',
                    wfHostname(), $tmpDir ) );
            return new MediaTransformError( 'thumbnail_error',
                $params['width'], $params['height'],
                wfMessage( 'thumbnail-temp-create' )->text()
            );
        }
        $ok = symlink( $srcPath, $lnPath );
        $cleaner = new ScopedCallback( function () use ( $tmpDir, $lnPath ) {
            Wikimedia\suppressWarnings();
            unlink( $lnPath );
            rmdir( $tmpDir );
            Wikimedia\restoreWarnings();
        } );
        if ( !$ok ) {
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not link %s to %s',
                    wfHostname(), $lnPath, $srcPath ) );
            return new MediaTransformError( 'thumbnail_error',
                $params['width'], $params['height'],
                wfMessage( 'thumbnail-temp-create' )
            );
        }

        $status = $this->rasterize( $lnPath, $dstPath, $physicalWidth, $physicalHeight, $lang );
        if ( $status === true ) {
            return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
        } else {
            return $status; // MediaTransformError
        }
    }

    public function rasterize( $srcPath, $dstPath, $width, $height, $lang = false ) {
        global $wgSVGConverters, $wgSVGConverter, $wgSVGConverterPath;
        $err = false;
        $retval = '';
        if ( isset( $wgSVGConverters[$wgSVGConverter] ) ) {
            if ( is_array( $wgSVGConverters[$wgSVGConverter] ) ) {
                // This is a PHP callable
                $func = $wgSVGConverters[$wgSVGConverter][0];
                if ( !is_callable( $func ) ) {
                    throw new MWException( "$func is not callable" );
                }
                $err = $func( $srcPath,
                    $dstPath,
                    $width,
                    $height,
                    $lang,
                    ...array_slice( $wgSVGConverters[$wgSVGConverter], 1 )
                );
                $retval = (bool)$err;
            } else {
                // External command
                $cmd = str_replace(
                    [ '$path/', '$width', '$height', '$input', '$output' ],
                    [ $wgSVGConverterPath ? Shell::escape( "$wgSVGConverterPath/" ) : "",
                        intval( $width ),
                        intval( $height ),
                        Shell::escape( $srcPath ),
                        Shell::escape( $dstPath ) ],
                    $wgSVGConverters[$wgSVGConverter]
                );

                $env = [];
                if ( $lang !== false ) {
                    $env['LANG'] = $lang;
                }

                wfDebug( __METHOD__ . ": $cmd\n" );
                $err = wfShellExecWithStderr( $cmd, $retval, $env );
            }
        }
        $removed = $this->removeBadFile( $dstPath, $retval );
        if ( $retval != 0 || $removed ) {
            $this->logErrorForExternalProcess( $retval, $err, $cmd );
            return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
        }

        return true;
    }

    public static function rasterizeImagickExt( $srcPath, $dstPath, $width, $height ) {
        $im = new Imagick( $srcPath );
        $im->setImageFormat( 'png' );
        $im->setBackgroundColor( 'transparent' );
        $im->setImageDepth( 8 );

        if ( !$im->thumbnailImage( intval( $width ), intval( $height ), /* fit */ false ) ) {
            return 'Could not resize image';
        }
        if ( !$im->writeImage( $dstPath ) ) {
            return "Could not write to $dstPath";
        }
    }

    function getImageSize( $file, $path, $metadata = false ) {
        if ( $metadata === false && $file instanceof File ) {
            $metadata = $file->getMetadata();
        }
        $metadata = $this->unpackMetadata( $metadata );

        if ( isset( $metadata['width'] ) && isset( $metadata['height'] ) ) {
            return [ $metadata['width'], $metadata['height'], 'SVG',
                "width=\"{$metadata['width']}\" height=\"{$metadata['height']}\"" ];
        } else { // error
            return [ 0, 0, 'SVG', "width=\"0\" height=\"0\"" ];
        }
    }

    public function getThumbType( $ext, $mime, $params = null ) {
        return [ 'png', 'image/png' ];
    }

    public function getLongDesc( $file ) {
        global $wgLang;

        $metadata = $this->unpackMetadata( $file->getMetadata() );
        if ( isset( $metadata['error'] ) ) {
            return wfMessage( 'svg-long-error', $metadata['error']['message'] )->text();
        }

        $size = $wgLang->formatSize( $file->getSize() );

        if ( $this->isAnimatedImage( $file ) ) {
            $msg = wfMessage( 'svg-long-desc-animated' );
        } else {
            $msg = wfMessage( 'svg-long-desc' );
        }

        $msg->numParams( $file->getWidth(), $file->getHeight() )->params( $size );

        return $msg->parse();
    }

    public function getMetadata( $file, $filename ) {
        $metadata = [ 'version' => self::SVG_METADATA_VERSION ];

        try {
            $svgReader = new SVGReader( $filename );
            $metadata += $svgReader->getMetadata();
        } catch ( Exception $e ) { // @todo SVG specific exceptions
            // File not found, broken, etc.
            $metadata['error'] = [
                'message' => $e->getMessage(),
                'code' => $e->getCode()
            ];
            wfDebug( __METHOD__ . ': ' . $e->getMessage() . "\n" );
        }

        return serialize( $metadata );
    }

    function unpackMetadata( $metadata ) {
        Wikimedia\suppressWarnings();
        $unser = unserialize( $metadata );
        Wikimedia\restoreWarnings();
        if ( isset( $unser['version'] ) && $unser['version'] == self::SVG_METADATA_VERSION ) {
            return $unser;
        } else {
            return false;
        }
    }

    function getMetadataType( $image ) {
        return 'parsed-svg';
    }

    public function isMetadataValid( $image, $metadata ) {
        $meta = $this->unpackMetadata( $metadata );
        if ( $meta === false ) {
            return self::METADATA_BAD;
        }
        if ( !isset( $meta['originalWidth'] ) ) {
            // Old but compatible
            return self::METADATA_COMPATIBLE;
        }

        return self::METADATA_GOOD;
    }

    protected function visibleMetadataFields() {
        $fields = [ 'objectname', 'imagedescription' ];

        return $fields;
    }

    public function formatMetadata( $file, $context = false ) {
        $result = [
            'visible' => [],
            'collapsed' => []
        ];
        $metadata = $file->getMetadata();
        if ( !$metadata ) {
            return false;
        }
        $metadata = $this->unpackMetadata( $metadata );
        if ( !$metadata || isset( $metadata['error'] ) ) {
            return false;
        }

        /* @todo Add a formatter
        $format = new FormatSVG( $metadata );
        $formatted = $format->getFormattedData();
        */

        // Sort fields into visible and collapsed
        $visibleFields = $this->visibleMetadataFields();

        $showMeta = false;
        foreach ( $metadata as $name => $value ) {
            $tag = strtolower( $name );
            if ( isset( self::$metaConversion[$tag] ) ) {
                $tag = strtolower( self::$metaConversion[$tag] );
            } else {
                // Do not output other metadata not in list
                continue;
            }
            $showMeta = true;
            self::addMeta( $result,
                in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
                'exif',
                $tag,
                $value
            );
        }

        return $showMeta ? $result : false;
    }

    public function validateParam( $name, $value ) {
        if ( in_array( $name, [ 'width', 'height' ] ) ) {
            // Reject negative heights, widths
            return ( $value > 0 );
        } elseif ( $name == 'lang' ) {
            // Validate $code
            if ( $value === '' || !Language::isValidCode( $value ) ) {
                return false;
            }

            return true;
        }

        // Only lang, width and height are acceptable keys
        return false;
    }

    public function makeParamString( $params ) {
        $lang = '';
        $code = $this->getLanguageFromParams( $params );
        if ( $code !== 'en' ) {
            $lang = 'lang' . strtolower( $code ) . '-';
        }
        if ( !isset( $params['width'] ) ) {
            return false;
        }

        return "$lang{$params['width']}px";
    }

    public function parseParamString( $str ) {
        $m = false;
        if ( preg_match( '/^lang([a-z]+(?:-[a-z]+)*)-(\d+)px$/i', $str, $m ) ) {
            return [ 'width' => array_pop( $m ), 'lang' => $m[1] ];
        } elseif ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
            return [ 'width' => $m[1], 'lang' => 'en' ];
        } else {
            return false;
        }
    }

    public function getParamMap() {
        return [ 'img_lang' => 'lang', 'img_width' => 'width' ];
    }

    protected function getScriptParams( $params ) {
        $scriptParams = [ 'width' => $params['width'] ];
        if ( isset( $params['lang'] ) ) {
            $scriptParams['lang'] = $params['lang'];
        }

        return $scriptParams;
    }

    public function getCommonMetaArray( File $file ) {
        $metadata = $file->getMetadata();
        if ( !$metadata ) {
            return [];
        }
        $metadata = $this->unpackMetadata( $metadata );
        if ( !$metadata || isset( $metadata['error'] ) ) {
            return [];
        }
        $stdMetadata = [];
        foreach ( $metadata as $name => $value ) {
            $tag = strtolower( $name );
            if ( $tag === 'originalwidth' || $tag === 'originalheight' ) {
                // Skip these. In the exif metadata stuff, it is assumed these
                // are measured in px, which is not the case here.
                continue;
            }
            if ( isset( self::$metaConversion[$tag] ) ) {
                $tag = self::$metaConversion[$tag];
                $stdMetadata[$tag] = $value;
            }
        }

        return $stdMetadata;
    }
}