PdfImage.php

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<?php
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\Shell\Shell;
use UtfNormal\Validator;
use Wikimedia\XMPReader\Reader as XMPReader;
 
class PdfImage {
 
    private $mFilename;
 
    function __construct( $filename ) {
        $this->mFilename = $filename;
    }
 
    public function isValid() {
        return true;
    }
 
    public function getImageSize() {
        $data = $this->retrieveMetadata();
        $size = self::getPageSize( $data, 1 );
 
        if ( $size ) {
            $width = $size['width'];
            $height = $size['height'];
            return [ $width, $height, 'Pdf',
                "width=\"$width\" height=\"$height\"" ];
        }
        return false;
    }
 
    public static function getPageSize( $data, $page ) {
        global $wgPdfHandlerDpi;
 
        if ( isset( $data['pages'][$page]['Page size'] ) ) {
            $o = $data['pages'][$page]['Page size'];
        } elseif ( isset( $data['Page size'] ) ) {
            $o = $data['Page size'];
        } else {
            $o = false;
        }
 
        if ( $o ) {
            if ( isset( $data['pages'][$page]['Page rot'] ) ) {
                $r = $data['pages'][$page]['Page rot'];
            } elseif ( isset( $data['Page rot'] ) ) {
                $r = $data['Page rot'];
            } else {
                $r = 0;
            }
            $size = explode( 'x', $o, 2 );
 
            if ( $size ) {
                $width  = intval( trim( $size[0] ) / 72 * $wgPdfHandlerDpi );
                $height = explode( ' ', trim( $size[1] ), 2 );
                $height = intval( trim( $height[0] ) / 72 * $wgPdfHandlerDpi );
                if ( ( $r / 90 ) & 1 ) {
                    // Swap width and height for landscape pages
                    $t = $width;
                    $width = $height;
                    $height = $t;
                }
 
                return [
                    'width' => $width,
                    'height' => $height
                ];
            }
        }
 
        return false;
    }
 
    public function retrieveMetaData() {
        global $wgPdfInfo, $wgPdftoText;
 
        if ( $wgPdfInfo ) {
            // Note in poppler 0.26 the -meta and page data options worked together,
            // but as of poppler 0.48 they must be queried separately.
            // https://bugs.freedesktop.org/show_bug.cgi?id=96801
            $cmdMeta = [
                $wgPdfInfo,
                '-enc', 'UTF-8', # Report metadata as UTF-8 text...
                '-meta',         # Report XMP metadata
                $this->mFilename,
            ];
            $resultMeta = Shell::command( $cmdMeta )
                ->execute();
 
            $cmdPages = [
                $wgPdfInfo,
                '-enc', 'UTF-8', # Report metadata as UTF-8 text...
                '-l', '9999999', # Report page sizes for all pages
                $this->mFilename,
            ];
            $resultPages = Shell::command( $cmdPages )
                ->execute();
 
            $dump = $resultMeta->getStdout() . $resultPages->getStdout();
            $data = $this->convertDumpToArray( $dump );
        } else {
            $data = null;
        }
 
        // Read text layer
        if ( isset( $wgPdftoText ) ) {
            $cmd = [ $wgPdftoText,  $this->mFilename, '-' ];
            $result = Shell::command( $cmd )
                ->execute();
            $retval = $result->getExitCode();
            $txt = $result->getStdout();
            if ( $retval == 0 ) {
                $txt = str_replace( "\r\n", "\n", $txt );
                $pages = explode( "\f", $txt );
                foreach ( $pages as $page => $pageText ) {
                    // Get rid of invalid UTF-8, strip control characters
                    // Note we need to do this per page, as \f page feed would be stripped.
                    $pages[$page] = Validator::cleanUp( $pageText );
                }
                $data['text'] = $pages;
            }
        }
        return $data;
    }
 
    protected function convertDumpToArray( $dump ) {
        if ( strval( $dump ) == '' ) {
            return false;
        }
 
        $lines = explode( "\n", $dump );
        $data = [];
 
        // Metadata is always the last item, and spans multiple lines.
        $inMetadata = false;
 
        // Basically this loop will go through each line, splitting key value
        // pairs on the colon, until it gets to a "Metadata:\n" at which point
        // it will gather all remaining lines into the xmp key.
        foreach ( $lines as $line ) {
            if ( $inMetadata ) {
                // Handle XMP differently due to diffence in line break
                $data['xmp'] .= "\n$line";
                continue;
            }
            $bits = explode( ':', $line, 2 );
            if ( count( $bits ) > 1 ) {
                $key = trim( $bits[0] );
                if ( $key === 'Metadata' ) {
                    $inMetadata = true;
                    $data['xmp'] = '';
                    continue;
                }
                $value = trim( $bits[1] );
                $matches = [];
                // "Page xx rot" will be in poppler 0.20's pdfinfo output
                // See https://bugs.freedesktop.org/show_bug.cgi?id=41867
                if ( preg_match( '/^Page +(\d+) (size|rot)$/', $key, $matches ) ) {
                    $data['pages'][$matches[1]][$matches[2] == 'size' ? 'Page size' : 'Page rot'] = $value;
                } else {
                    $data[$key] = $value;
                }
            }
        }
        $data = $this->postProcessDump( $data );
        return $data;
    }
 
    protected function postProcessDump( array $data ) {
        $meta = new BitmapMetadataHandler();
        $items = [];
        foreach ( $data as $key => $val ) {
            switch ( $key ) {
                case 'Title':
                    $items['ObjectName'] = $val;
                    break;
                case 'Subject':
                    $items['ImageDescription'] = $val;
                    break;
                case 'Keywords':
                    // Sometimes we have empty keywords. This seems
                    // to be a product of how pdfinfo deals with keywords
                    // with spaces in them. Filter such empty keywords
                    $keyList = array_filter( explode( ' ', $val ) );
                    if ( count( $keyList ) > 0 ) {
                        $items['Keywords'] = $keyList;
                    }
                    break;
                case 'Author':
                    $items['Artist'] = $val;
                    break;
                case 'Creator':
                    // Program used to create file.
                    // Different from program used to convert to pdf.
                    $items['Software'] = $val;
                    break;
                case 'Producer':
                    // Conversion program
                    $items['pdf-Producer'] = $val;
                    break;
                case 'ModTime':
                    $timestamp = wfTimestamp( TS_EXIF, $val );
                    if ( $timestamp ) {
                        // 'if' is just paranoia
                        $items['DateTime'] = $timestamp;
                    }
                    break;
                case 'CreationTime':
                    $timestamp = wfTimestamp( TS_EXIF, $val );
                    if ( $timestamp ) {
                        $items['DateTimeDigitized'] = $timestamp;
                    }
                    break;
                // These last two (version and encryption) I was unsure
                // if we should include in the table, since they aren't
                // all that useful to editors. I leaned on the side
                // of including. However not including if file
                // is optimized/linearized since that is really useless
                // to an editor.
                case 'PDF version':
                    $items['pdf-Version'] = $val;
                    break;
                case 'Encrypted':
                    // @todo: The value isn't i18n-ised. The appropriate
                    // place to do that is in FormatMetadata.php
                    // should add a hook a there.
                    // For reference, if encrypted this fields value looks like:
                    // "yes (print:yes copy:no change:no addNotes:no)"
                    $items['pdf-Encrypted'] = $val;
                    break;
                // Note 'pages' and 'Pages' are different keys (!)
                case 'pages':
                    // A pdf document can have multiple sized pages in it.
                    // (However 95% of the time, all pages are the same size)
                    // get a list of all the unique page sizes in document.
                    // This doesn't do anything with rotation as of yet,
                    // mostly because I am unsure of what a good way to
                    // present that information to the user would be.
                    $pageSizes = [];
                    foreach ( $val as $page ) {
                        if ( isset( $page['Page size'] ) ) {
                            $pageSizes[$page['Page size']] = true;
                        }
                    }
 
                    $pageSizeArray = array_keys( $pageSizes );
                    if ( count( $pageSizeArray ) > 0 ) {
                        $items['pdf-PageSize'] = $pageSizeArray;
                    }
                    break;
            }
 
        }
        $meta->addMetadata( $items, 'native' );
 
        if ( isset( $data['xmp'] ) && XMPReader::isSupported() ) {
            // @todo: This only handles generic xmp properties. Would be improved
            // by handling pdf xmp properties (pdf and pdfx) via a hook.
            $xmp = new XMPReader( LoggerFactory::getInstance( 'XMP' ) );
            $xmp->parse( $data['xmp'] );
            $xmpRes = $xmp->getResults();
            foreach ( $xmpRes as $type => $xmpSection ) {
                $meta->addMetadata( $xmpSection, $type );
            }
        }
        unset( $data['xmp'] );
        $data['mergedMetadata'] = $meta->getMetadataArray();
        return $data;
    }
}