includes/media/DjVu.php

   1 <?php
   2
   3 class DjVuHandler extends ImageHandler {
   4         function isEnabled() {
   5                 global $wgDjvuRenderer, $wgDjvuDump, $wgDjvuToXML;
   6                 if ( !$wgDjvuRenderer || ( !$wgDjvuDump && !$wgDjvuToXML ) ) {
   7                         wfDebug( "DjVu is disabled, please set \$wgDjvuRenderer and \$wgDjvuDump\n" );
   8                         return false;
   9                 } else {
  10                         return true;
  11                 }
  12         }
  13
  14         function mustRender() { return true; }
  15         function isMultiPage() { return true; }
  16
  17         function validateParam( $name, $value ) {
  18                 if ( in_array( $name, array( 'width', 'height', 'page' ) ) ) {
  19                         if ( $value <= 0 ) {
  20                                 return false;
  21                         } else {
  22                                 return true;
  23                         }
  24                 } else {
  25                         return false;
  26                 }
  27         }
  28
  29         function makeParamString( $params ) {
  30                 $page = isset( $params['page'] ) ? $params['page'] : 1;
  31                 if ( !isset( $params['width'] ) ) {
  32                         return false;
  33                 }
  34                 return "{$params['width']}px-page{$page}";
  35         }
  36
  37         function parseParamString( $str ) {
  38                 $m = false;
  39                 if ( preg_match( '/^(\d+)px-page(\d+)$/', $str, $m ) ) {
  40                         return array( 'width' => $m[1], 'page' => $m[2] );
  41                 } else {
  42                         return false;
  43                 }
  44         }
  45
  46         function getScriptParams( $params ) {
  47                 return array(
  48                         'width' => $params['width'],
  49                         'page' => $params['page'],
  50                 );
  51         }
  52
  53         function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
  54                 global $wgDjvuRenderer, $wgDjvuPostProcessor;
  55
  56                 // Fetch XML and check it, to give a more informative error message than the one which
  57                 // normaliseParams will inevitably give.
  58                 $xml = $image->getMetadata();
  59                 if ( !$xml ) {
  60                         return new MediaTransformError( 'thumbnail_error', @$params['width'], @$params['height'],
  61                                 wfMsg( 'djvu_no_xml' ) );
  62                 }
  63
  64                 if ( !$this->normaliseParams( $image, $params ) ) {
  65                         return new TransformParameterError( $params );
  66                 }
  67                 $width = $params['width'];
  68                 $height = $params['height'];
  69                 $srcPath = $image->getImagePath();
  70                 $page = $params['page'];
  71                 $pageCount = $this->pageCount( $image );
  72                 if ( $page > $this->pageCount( $image ) ) {
  73                         return new MediaTransformError( 'thumbnail_error', $width, $height, wfMsg( 'djvu_page_error' ) );
  74                 }
  75
  76                 if ( $flags & self::TRANSFORM_LATER ) {
  77                         return new ThumbnailImage( $dstUrl, $width, $height, $dstPath );
  78                 }
  79
  80                 if ( !wfMkdirParents( dirname( $dstPath ) ) ) {
  81                         return new MediaTransformError( 'thumbnail_error', $width, $height, wfMsg( 'thumbnail_dest_directory' ) );
  82                 }
  83
  84                 # Use a subshell (brackets) to aggregate stderr from both pipeline commands
  85                 # before redirecting it to the overall stdout. This works in both Linux and Windows XP.
  86                 $cmd = '(' . wfEscapeShellArg( $wgDjvuRenderer ) . " -format=ppm -page={$page} -size={$width}x{$height} " .
  87                         wfEscapeShellArg( $srcPath );
  88                 if ( $wgDjvuPostProcessor ) {
  89                         $cmd .= " | {$wgDjvuPostProcessor}";
  90                 }
  91                 $cmd .= ' > ' . wfEscapeShellArg($dstPath) . ') 2>&1';
  92                 wfProfileIn( 'ddjvu' );
  93                 wfDebug( __METHOD__.": $cmd\n" );
  94                 $err = wfShellExec( $cmd, $retval );
  95                 wfProfileOut( 'ddjvu' );
  96
  97                 $removed = $this->removeBadFile( $dstPath, $retval );
  98                 if ( $retval != 0 || $removed ) {
  99                         wfDebugLog( 'thumbnail',
 100                                 sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
 101                                         wfHostname(), $retval, trim($err), $cmd ) );
 102                         return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
 103                 } else {
 104                         return new ThumbnailImage( $dstUrl, $width, $height, $dstPath );
 105                 }
 106         }
 107
 108         /**
 109          * Cache an instance of DjVuImage in an Image object, return that instance
 110          */
 111         function getDjVuImage( $image, $path ) {
 112                 if ( !$image ) {
 113                         $deja = new DjVuImage( $path );
 114                 } elseif ( !isset( $image->dejaImage ) ) {
 115                         $deja = $image->dejaImage = new DjVuImage( $path );
 116                 } else {
 117                         $deja = $image->dejaImage;
 118                 }
 119                 return $deja;
 120         }
 121
 122         /**
 123          * Cache a document tree for the DjVu XML metadata
 124          */
 125         function getMetaTree( $image ) {
 126                 if ( isset( $image->dejaMetaTree ) ) {
 127                         return $image->dejaMetaTree;
 128                 }
 129
 130                 $metadata = $image->getMetadata();
 131                 if ( !$this->isMetadataValid( $image, $metadata ) ) {
 132                         wfDebug( "DjVu XML metadata is invalid or missing, should have been fixed in upgradeRow\n" );
 133                         return false;
 134                 }
 135                 wfProfileIn( __METHOD__ );
 136
 137                 wfSuppressWarnings();
 138                 try {
 139                         $image->dejaMetaTree = new SimpleXMLElement( $metadata );
 140                 } catch( Exception $e ) {
 141                         wfDebug( "Bogus multipage XML metadata on '$image->name'\n" );
 142                         // Set to false rather than null to avoid further attempts
 143                         $image->dejaMetaTree = false;
 144                 }
 145                 wfRestoreWarnings();
 146                 wfProfileOut( __METHOD__ );
 147                 return $image->dejaMetaTree;
 148         }
 149
 150         function getImageSize( $image, $path ) {
 151                 return $this->getDjVuImage( $image, $path )->getImageSize();
 152         }
 153
 154         function getThumbType( $ext, $mime ) {
 155                 global $wgDjvuOutputExtension;
 156                 static $mime;
 157                 if ( !isset( $mime ) ) {
 158                         $magic = MimeMagic::singleton();
 159                         $mime = $magic->guessTypesForExtension( $wgDjvuOutputExtension );
 160                 }
 161                 return array( $wgDjvuOutputExtension, $mime );
 162         }
 163
 164         function getMetadata( $image, $path ) {
 165                 wfDebug( "Getting DjVu metadata for $path\n" );
 166                 return $this->getDjVuImage( $image, $path )->retrieveMetaData();
 167         }
 168
 169         function getMetadataType( $image ) {
 170                 return 'djvuxml';
 171         }
 172
 173         function isMetadataValid( $image, $metadata ) {
 174                 return !empty( $metadata ) && $metadata != serialize(array());
 175         }
 176
 177         function pageCount( $image ) {
 178                 $tree = $this->getMetaTree( $image );
 179                 if ( !$tree ) {
 180                         return false;
 181                 }
 182                 return count( $tree->xpath( '//OBJECT' ) );
 183         }
 184
 185         function getPageDimensions( $image, $page ) {
 186                 $tree = $this->getMetaTree( $image );
 187                 if ( !$tree ) {
 188                         return false;
 189                 }
 190
 191                 $o = $tree->BODY[0]->OBJECT[$page-1];
 192                 if ( $o ) {
 193                         return array(
 194                                 'width' => intval( $o['width'] ),
 195                                 'height' => intval( $o['height'] )
 196                         );
 197                 } else {
 198                         return false;
 199                 }
 200         }
 201 }
 202
 203 ?>