Implement extension registration from an extension.json file

[mediawiki.git] / includes / media / BitmapMetadataHandler.php

<?php
/**
 * Extraction of metadata from different bitmap image types.
 *
 * 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 Media
 */

/**
 * Class to deal with reconciling and extracting metadata from bitmap images.
 * This is meant to comply with http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf
 *
 * This sort of acts as an intermediary between MediaHandler::getMetadata
 * and the various metadata extractors.
 *
 * @todo Other image formats.
 * @ingroup Media
 */
class BitmapMetadataHandler {
        /** @var array */
        private $metadata = array();

        /** @var array Metadata priority */
        private $metaPriority = array(
                20 => array( 'other' ),
                40 => array( 'native' ),
                60 => array( 'iptc-good-hash', 'iptc-no-hash' ),
                70 => array( 'xmp-deprecated' ),
                80 => array( 'xmp-general' ),
                90 => array( 'xmp-exif' ),
                100 => array( 'iptc-bad-hash' ),
                120 => array( 'exif' ),
        );

        /** @var string */
        private $iptcType = 'iptc-no-hash';

        /**
         * This does the photoshop image resource app13 block
         * of interest, IPTC-IIM metadata is stored here.
         *
         * Mostly just calls doPSIR and doIPTC
         *
         * @param string $app13 String containing app13 block from jpeg file
         */
        private function doApp13( $app13 ) {
                try {
                        $this->iptcType = JpegMetadataExtractor::doPSIR( $app13 );
                } catch ( MWException $e ) {
                        // Error reading the iptc hash information.
                        // This probably means the App13 segment is something other than what we expect.
                        // However, still try to read it, and treat it as if the hash didn't exist.
                        wfDebug( "Error parsing iptc data of file: " . $e->getMessage() . "\n" );
                        $this->iptcType = 'iptc-no-hash';
                }

                $iptc = IPTC::parse( $app13 );
                $this->addMetadata( $iptc, $this->iptcType );
        }

        /**
         * Get exif info using exif class.
         * Basically what used to be in BitmapHandler::getMetadata().
         * Just calls stuff in the Exif class.
         *
         * Parameters are passed to the Exif class.
         *
         * @param string $filename
         * @param string $byteOrder
         */
        function getExif( $filename, $byteOrder ) {
                global $wgShowEXIF;
                if ( file_exists( $filename ) && $wgShowEXIF ) {
                        $exif = new Exif( $filename, $byteOrder );
                        $data = $exif->getFilteredData();
                        if ( $data ) {
                                $this->addMetadata( $data, 'exif' );
                        }
                }
        }

        /** Add misc metadata. Warning: atm if the metadata category
         * doesn't have a priority, it will be silently discarded.
         *
         * @param array $metaArray Array of metadata values
         * @param string $type Type. defaults to other. if two things have the same type they're merged
         */
        function addMetadata( $metaArray, $type = 'other' ) {
                if ( isset( $this->metadata[$type] ) ) {
                        /* merge with old data */
                        $metaArray = $metaArray + $this->metadata[$type];
                }

                $this->metadata[$type] = $metaArray;
        }

        /**
         * Merge together the various types of metadata
         * the different types have different priorites,
         * and are merged in order.
         *
         * This function is generally called by the media handlers' getMetadata()
         *
         * @return array Metadata array
         */
        function getMetadataArray() {
                // this seems a bit ugly... This is all so its merged in right order
                // based on the MWG recomendation.
                $temp = array();
                krsort( $this->metaPriority );
                foreach ( $this->metaPriority as $pri ) {
                        foreach ( $pri as $type ) {
                                if ( isset( $this->metadata[$type] ) ) {
                                        // Do some special casing for multilingual values.
                                        // Don't discard translations if also as a simple value.
                                        foreach ( $this->metadata[$type] as $itemName => $item ) {
                                                if ( is_array( $item ) && isset( $item['_type'] ) && $item['_type'] === 'lang' ) {
                                                        if ( isset( $temp[$itemName] ) && !is_array( $temp[$itemName] ) ) {
                                                                $default = $temp[$itemName];
                                                                $temp[$itemName] = $item;
                                                                $temp[$itemName]['x-default'] = $default;
                                                                unset( $this->metadata[$type][$itemName] );
                                                        }
                                                }
                                        }

                                        $temp = $temp + $this->metadata[$type];
                                }
                        }
                }

                return $temp;
        }

        /** Main entry point for jpeg's.
         *
         * @param string $filename Filename (with full path)
         * @return array Metadata result array.
         * @throws MWException On invalid file.
         */
        static function Jpeg( $filename ) {
                $showXMP = function_exists( 'xml_parser_create_ns' );
                $meta = new self();

                $seg = JpegMetadataExtractor::segmentSplitter( $filename );
                if ( isset( $seg['COM'] ) && isset( $seg['COM'][0] ) ) {
                        $meta->addMetadata( array( 'JPEGFileComment' => $seg['COM'] ), 'native' );
                }
                if ( isset( $seg['PSIR'] ) && count( $seg['PSIR'] ) > 0 ) {
                        foreach ( $seg['PSIR'] as $curPSIRValue ) {
                                $meta->doApp13( $curPSIRValue );
                        }
                }
                if ( isset( $seg['XMP'] ) && $showXMP ) {
                        $xmp = new XMPReader();
                        $xmp->parse( $seg['XMP'] );
                        foreach ( $seg['XMP_ext'] as $xmpExt ) {
                                /* Support for extended xmp in jpeg files
                                 * is not well tested and a bit fragile.
                                 */
                                $xmp->parseExtended( $xmpExt );
                        }
                        $res = $xmp->getResults();
                        foreach ( $res as $type => $array ) {
                                $meta->addMetadata( $array, $type );
                        }
                }
                if ( isset( $seg['byteOrder'] ) ) {
                        $meta->getExif( $filename, $seg['byteOrder'] );
                }

                return $meta->getMetadataArray();
        }

        /** Entry point for png
         * At some point in the future this might
         * merge the png various tEXt chunks to that
         * are interesting, but for now it only does XMP
         *
         * @param string $filename Full path to file
         * @return array Array for storage in img_metadata.
         */
        public static function PNG( $filename ) {
                $showXMP = function_exists( 'xml_parser_create_ns' );

                $meta = new self();
                $array = PNGMetadataExtractor::getMetadata( $filename );
                if ( isset( $array['text']['xmp']['x-default'] )
                        && $array['text']['xmp']['x-default'] !== '' && $showXMP
                ) {
                        $xmp = new XMPReader();
                        $xmp->parse( $array['text']['xmp']['x-default'] );
                        $xmpRes = $xmp->getResults();
                        foreach ( $xmpRes as $type => $xmpSection ) {
                                $meta->addMetadata( $xmpSection, $type );
                        }
                }
                unset( $array['text']['xmp'] );
                $meta->addMetadata( $array['text'], 'native' );
                unset( $array['text'] );
                $array['metadata'] = $meta->getMetadataArray();
                $array['metadata']['_MW_PNG_VERSION'] = PNGMetadataExtractor::VERSION;

                return $array;
        }

        /** function for gif images.
         *
         * They don't really have native metadata, so just merges together
         * XMP and image comment.
         *
         * @param string $filename Full path to file
         * @return array Metadata array
         */
        public static function GIF( $filename ) {

                $meta = new self();
                $baseArray = GIFMetadataExtractor::getMetadata( $filename );

                if ( count( $baseArray['comment'] ) > 0 ) {
                        $meta->addMetadata( array( 'GIFFileComment' => $baseArray['comment'] ), 'native' );
                }

                if ( $baseArray['xmp'] !== '' && function_exists( 'xml_parser_create_ns' ) ) {
                        $xmp = new XMPReader();
                        $xmp->parse( $baseArray['xmp'] );
                        $xmpRes = $xmp->getResults();
                        foreach ( $xmpRes as $type => $xmpSection ) {
                                $meta->addMetadata( $xmpSection, $type );
                        }
                }

                unset( $baseArray['comment'] );
                unset( $baseArray['xmp'] );

                $baseArray['metadata'] = $meta->getMetadataArray();
                $baseArray['metadata']['_MW_GIF_VERSION'] = GIFMetadataExtractor::VERSION;

                return $baseArray;
        }

        /**
         * This doesn't do much yet, but eventually I plan to add
         * XMP support for Tiff. (PHP's exif support already extracts
         * but needs some further processing because PHP's exif support
         * is stupid...)
         *
         * @todo Add XMP support, so this function actually makes sense to put here.
         *
         * The various exceptions this throws are caught later.
         * @param string $filename
         * @throws MWException
         * @return array The metadata.
         */
        public static function Tiff( $filename ) {
                if ( file_exists( $filename ) ) {
                        $byteOrder = self::getTiffByteOrder( $filename );
                        if ( !$byteOrder ) {
                                throw new MWException( "Error determining byte order of $filename" );
                        }
                        $exif = new Exif( $filename, $byteOrder );
                        $data = $exif->getFilteredData();
                        if ( $data ) {
                                $data['MEDIAWIKI_EXIF_VERSION'] = Exif::version();

                                return $data;
                        } else {
                                throw new MWException( "Could not extract data from tiff file $filename" );
                        }
                } else {
                        throw new MWException( "File doesn't exist - $filename" );
                }
        }

        /**
         * Read the first 2 bytes of a tiff file to figure out
         * Little Endian or Big Endian. Needed for exif stuff.
         *
         * @param string $filename The filename
         * @return string 'BE' or 'LE' or false
         */
        static function getTiffByteOrder( $filename ) {
                $fh = fopen( $filename, 'rb' );
                if ( !$fh ) {
                        return false;
                }
                $head = fread( $fh, 2 );
                fclose( $fh );

                switch ( $head ) {
                        case 'II':
                                return 'LE'; // II for intel.
                        case 'MM':
                                return 'BE'; // MM for motorla.
                        default:
                                return false; // Something went wrong.

                }
        }
}