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[mediawiki.git] / includes / resourceloader / ResourceLoaderImage.php

<?php
/**
 * Class encapsulating an image used in a ResourceLoaderImageModule.
 *
 * 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
 */

/**
 * Class encapsulating an image used in a ResourceLoaderImageModule.
 *
 * @since 1.25
 */
class ResourceLoaderImage {

        /**
         * Map of allowed file extensions to their MIME types.
         * @var array
         */
        protected static $fileTypes = array(
                'svg' => 'image/svg+xml',
                'png' => 'image/png',
                'gif' => 'image/gif',
                'jpg' => 'image/jpg',
        );

        /**
         * @param string $name Image name
         * @param string $module Module name
         * @param string|array $descriptor Path to image file, or array structure containing paths
         * @param string $basePath Directory to which paths in descriptor refer
         * @param array $variants
         * @throws InvalidArgumentException
         */
        public function __construct( $name, $module, $descriptor, $basePath, $variants ) {
                $this->name = $name;
                $this->module = $module;
                $this->descriptor = $descriptor;
                $this->basePath = $basePath;
                $this->variants = $variants;

                // Expand shorthands:
                // array( "en,de,fr" => "foo.svg" )
                // → array( "en" => "foo.svg", "de" => "foo.svg", "fr" => "foo.svg" )
                if ( is_array( $this->descriptor ) && isset( $this->descriptor['lang'] ) ) {
                        foreach ( array_keys( $this->descriptor['lang'] ) as $langList ) {
                                if ( strpos( $langList, ',' ) !== false ) {
                                        $this->descriptor['lang'] += array_fill_keys(
                                                explode( ',', $langList ),
                                                $this->descriptor['lang'][$langList]
                                        );
                                        unset( $this->descriptor['lang'][$langList] );
                                }
                        }
                }

                // Ensure that all files have common extension.
                $extensions = array();
                $descriptor = (array)$descriptor;
                array_walk_recursive( $descriptor, function ( $path ) use ( &$extensions ) {
                        $extensions[] = pathinfo( $path, PATHINFO_EXTENSION );
                } );
                $extensions = array_unique( $extensions );
                if ( count( $extensions ) !== 1 ) {
                        throw new InvalidArgumentException(
                                "File type for different image files of '$name' not the same"
                        );
                }
                $ext = $extensions[0];
                if ( !isset( self::$fileTypes[$ext] ) ) {
                        throw new InvalidArgumentException(
                                "Invalid file type for image files of '$name' (valid: svg, png, gif, jpg)"
                        );
                }
                $this->extension = $ext;
        }

        /**
         * Get name of this image.
         *
         * @return string
         */
        public function getName() {
                return $this->name;
        }

        /**
         * Get name of the module this image belongs to.
         *
         * @return string
         */
        public function getModule() {
                return $this->module;
        }

        /**
         * Get the list of variants this image can be converted to.
         *
         * @return string[]
         */
        public function getVariants() {
                return array_keys( $this->variants );
        }

        /**
         * Get the path to image file for given context.
         *
         * @param ResourceLoaderContext $context Any context
         * @return string
         */
        public function getPath( ResourceLoaderContext $context ) {
                $desc = $this->descriptor;
                if ( is_string( $desc ) ) {
                        return $this->basePath . '/' . $desc;
                } elseif ( isset( $desc['lang'][$context->getLanguage()] ) ) {
                        return $this->basePath . '/' . $desc['lang'][$context->getLanguage()];
                } elseif ( isset( $desc[$context->getDirection()] ) ) {
                        return $this->basePath . '/' . $desc[$context->getDirection()];
                } else {
                        return $this->basePath . '/' . $desc['default'];
                }
        }

        /**
         * Get the extension of the image.
         *
         * @param string $format Format to get the extension for, 'original' or 'rasterized'
         * @return string Extension without leading dot, e.g. 'png'
         */
        public function getExtension( $format = 'original' ) {
                if ( $format === 'rasterized' && $this->extension === 'svg' ) {
                        return 'png';
                } else {
                        return $this->extension;
                }
        }

        /**
         * Get the MIME type of the image.
         *
         * @param string $format Format to get the MIME type for, 'original' or 'rasterized'
         * @return string
         */
        public function getMimeType( $format = 'original' ) {
                $ext = $this->getExtension( $format );
                return self::$fileTypes[$ext];
        }

        /**
         * Get the load.php URL that will produce this image.
         *
         * @param ResourceLoaderContext $context Any context
         * @param string $script URL to load.php
         * @param string|null $variant Variant to get the URL for
         * @param string $format Format to get the URL for, 'original' or 'rasterized'
         * @return string
         */
        public function getUrl( ResourceLoaderContext $context, $script, $variant, $format ) {
                $query = array(
                        'modules' => $this->getModule(),
                        'image' => $this->getName(),
                        'variant' => $variant,
                        'format' => $format,
                        'lang' => $context->getLanguage(),
                        'version' => $context->getVersion(),
                );

                return wfExpandUrl( wfAppendQuery( $script, $query ), PROTO_RELATIVE );
        }

        /**
         * Get the data: URI that will produce this image.
         *
         * @param ResourceLoaderContext $context Any context
         * @param string|null $variant Variant to get the URI for
         * @param string $format Format to get the URI for, 'original' or 'rasterized'
         * @return string
         */
        public function getDataUri( ResourceLoaderContext $context, $variant, $format ) {
                $type = $this->getMimeType( $format );
                $contents = $this->getImageData( $context, $variant, $format );
                return CSSMin::encodeStringAsDataURI( $contents, $type );
        }

        /**
         * Get actual image data for this image. This can be saved to a file or sent to the browser to
         * produce the converted image.
         *
         * Call getExtension() or getMimeType() with the same $format argument to learn what file type the
         * returned data uses.
         *
         * @param ResourceLoaderContext $context Image context, or any context if $variant and $format
         *     given.
         * @param string|null $variant Variant to get the data for. Optional; if given, overrides the data
         *     from $context.
         * @param string $format Format to get the data for, 'original' or 'rasterized'. Optional; if
         *     given, overrides the data from $context.
         * @return string|false Possibly binary image data, or false on failure
         * @throws MWException If the image file doesn't exist
         */
        public function getImageData( ResourceLoaderContext $context, $variant = false, $format = false ) {
                if ( $variant === false ) {
                        $variant = $context->getVariant();
                }
                if ( $format === false ) {
                        $format = $context->getFormat();
                }

                $path = $this->getPath( $context );
                if ( !file_exists( $path ) ) {
                        throw new MWException( "File '$path' does not exist" );
                }

                if ( $this->getExtension() !== 'svg' ) {
                        return file_get_contents( $path );
                }

                if ( $variant && isset( $this->variants[$variant] ) ) {
                        $data = $this->variantize( $this->variants[$variant], $context );
                } else {
                        $data = file_get_contents( $path );
                }

                if ( $format === 'rasterized' ) {
                        $data = $this->rasterize( $data );
                        if ( !$data ) {
                                wfDebugLog( 'ResourceLoaderImage', __METHOD__ . " failed to rasterize for $path" );
                        }
                }

                return $data;
        }

        /**
         * Send response headers (using the header() function) that are necessary to correctly serve the
         * image data for this image, as returned by getImageData().
         *
         * Note that the headers are independent of the language or image variant.
         *
         * @param ResourceLoaderContext $context Image context
         */
        public function sendResponseHeaders( ResourceLoaderContext $context ) {
                $format = $context->getFormat();
                $mime = $this->getMimeType( $format );
                $filename = $this->getName() . '.' . $this->getExtension( $format );

                header( 'Content-Type: ' . $mime );
                header( 'Content-Disposition: ' .
                        FileBackend::makeContentDisposition( 'inline', $filename ) );
        }

        /**
         * Convert this image, which is assumed to be SVG, to given variant.
         *
         * @param array $variantConf Array with a 'color' key, its value will be used as fill color
         * @param ResourceLoaderContext $context Image context
         * @return string New SVG file data
         */
        protected function variantize( $variantConf, ResourceLoaderContext $context ) {
                $dom = new DomDocument;
                $dom->load( $this->getPath( $context ) );
                $root = $dom->documentElement;
                $wrapper = $dom->createElement( 'g' );
                while ( $root->firstChild ) {
                        $wrapper->appendChild( $root->firstChild );
                }
                $root->appendChild( $wrapper );
                $wrapper->setAttribute( 'fill', $variantConf['color'] );
                return $dom->saveXml();
        }

        /**
         * Massage the SVG image data for converters which don't understand some path data syntax.
         *
         * This is necessary for rsvg and ImageMagick when compiled with rsvg support.
         * Upstream bug is https://bugzilla.gnome.org/show_bug.cgi?id=620923, fixed 2014-11-10, so
         * this will be needed for a while. (T76852)
         *
         * @param string $svg SVG image data
         * @return string Massaged SVG image data
         */
        protected function massageSvgPathdata( $svg ) {
                $dom = new DomDocument;
                $dom->loadXml( $svg );
                foreach ( $dom->getElementsByTagName( 'path' ) as $node ) {
                        $pathData = $node->getAttribute( 'd' );
                        // Make sure there is at least one space between numbers, and that leading zero is not omitted.
                        // rsvg has issues with syntax like "M-1-2" and "M.445.483" and especially "M-.445-.483".
                        $pathData = preg_replace( '/(-?)(\d*\.\d+|\d+)/', ' ${1}0$2 ', $pathData );
                        // Strip unnecessary leading zeroes for prettiness, not strictly necessary
                        $pathData = preg_replace( '/([ -])0(\d)/', '$1$2', $pathData );
                        $node->setAttribute( 'd', $pathData );
                }
                return $dom->saveXml();
        }

        /**
         * Convert passed image data, which is assumed to be SVG, to PNG.
         *
         * @param string $svg SVG image data
         * @return string|bool PNG image data, or false on failure
         */
        protected function rasterize( $svg ) {
                /**
                 * This code should be factored out to a separate method on SvgHandler, or perhaps a separate
                 * class, with a separate set of configuration settings.
                 *
                 * This is a distinct use case from regular SVG rasterization:
                 * * We can skip many sanity and security checks (as the images come from a trusted source,
                 *   rather than from the user).
                 * * We need to provide extra options to some converters to achieve acceptable quality for very
                 *   small images, which might cause performance issues in the general case.
                 * * We want to directly pass image data to the converter, rather than a file path.
                 *
                 * See https://phabricator.wikimedia.org/T76473#801446 for examples of what happens with the
                 * default settings.
                 *
                 * For now, we special-case rsvg (used in WMF production) and do a messy workaround for other
                 * converters.
                 */

                global $wgSVGConverter, $wgSVGConverterPath;

                $svg = $this->massageSvgPathdata( $svg );

                // Sometimes this might be 'rsvg-secure'. Long as it's rsvg.
                if ( strpos( $wgSVGConverter, 'rsvg' ) === 0 ) {
                        $command = 'rsvg-convert';
                        if ( $wgSVGConverterPath ) {
                                $command = wfEscapeShellArg( "$wgSVGConverterPath/" ) . $command;
                        }

                        $process = proc_open(
                                $command,
                                array( 0 => array( 'pipe', 'r' ), 1 => array( 'pipe', 'w' ) ),
                                $pipes
                        );

                        if ( is_resource( $process ) ) {
                                fwrite( $pipes[0], $svg );
                                fclose( $pipes[0] );
                                $png = stream_get_contents( $pipes[1] );
                                fclose( $pipes[1] );
                                proc_close( $process );

                                return $png ?: false;
                        }
                        return false;

                } else {
                        // Write input to and read output from a temporary file
                        $tempFilenameSvg = tempnam( wfTempDir(), 'ResourceLoaderImage' );
                        $tempFilenamePng = tempnam( wfTempDir(), 'ResourceLoaderImage' );

                        file_put_contents( $tempFilenameSvg, $svg );

                        $metadata = SVGMetadataExtractor::getMetadata( $tempFilenameSvg );
                        if ( !isset( $metadata['width'] ) || !isset( $metadata['height'] ) ) {
                                unlink( $tempFilenameSvg );
                                return false;
                        }

                        $handler = new SvgHandler;
                        $res = $handler->rasterize(
                                $tempFilenameSvg,
                                $tempFilenamePng,
                                $metadata['width'],
                                $metadata['height']
                        );
                        unlink( $tempFilenameSvg );

                        $png = null;
                        if ( $res === true ) {
                                $png = file_get_contents( $tempFilenamePng );
                                unlink( $tempFilenamePng );
                        }

                        return $png ?: false;
                }
        }
}