includes/media/DjVu.php

   1 <?php
   2
   3 /**
   4  * @addtogroup Media
   5  */
   6 class DjVuHandler extends ImageHandler {
   7         function isEnabled() {
   8                 global $wgDjvuRenderer, $wgDjvuDump, $wgDjvuToXML;
   9                 if ( !$wgDjvuRenderer || ( !$wgDjvuDump && !$wgDjvuToXML ) ) {
  10                         wfDebug( "DjVu is disabled, please set \$wgDjvuRenderer and \$wgDjvuDump\n" );
  11                         return false;
  12                 } else {
  13                         return true;
  14                 }
  15         }
  16
  17         function mustRender() { return true; }
  18         function isMultiPage() { return true; }
  19
  20         function getParamMap() {
  21                 return array(
  22                         'img_width' => 'width',
  23                         'img_page' => 'page',
  24                 );
  25         }
  26
  27         function validateParam( $name, $value ) {
  28                 if ( in_array( $name, array( 'width', 'height', 'page' ) ) ) {
  29                         if ( $value <= 0 ) {
  30                                 return false;
  31                         } else {
  32                                 return true;
  33                         }
  34                 } else {
  35                         return false;
  36                 }
  37         }
  38
  39         function makeParamString( $params ) {
  40                 $page = isset( $params['page'] ) ? $params['page'] : 1;
  41                 if ( !isset( $params['width'] ) ) {
  42                         return false;
  43                 }
  44                 return "page{$page}-{$params['width']}px";
  45         }
  46
  47         function parseParamString( $str ) {
  48                 $m = false;
  49                 if ( preg_match( '/^page(\d+)-(\d+)px$/', $str, $m ) ) {
  50                         return array( 'width' => $m[2], 'page' => $m[1] );
  51                 } else {
  52                         return false;
  53                 }
  54         }
  55
  56         function getScriptParams( $params ) {
  57                 return array(
  58                         'width' => $params['width'],
  59                         'page' => $params['page'],
  60                 );
  61         }
  62
  63         function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
  64                 global $wgDjvuRenderer, $wgDjvuPostProcessor;
  65
  66                 // Fetch XML and check it, to give a more informative error message than the one which
  67                 // normaliseParams will inevitably give.
  68                 $xml = $image->getMetadata();
  69                 if ( !$xml ) {
  70                         return new MediaTransformError( 'thumbnail_error', @$params['width'], @$params['height'],
  71                                 wfMsg( 'djvu_no_xml' ) );
  72                 }
  73
  74                 if ( !$this->normaliseParams( $image, $params ) ) {
  75                         return new TransformParameterError( $params );
  76                 }
  77                 $width = $params['width'];
  78                 $height = $params['height'];
  79                 $srcPath = $image->getPath();
  80                 $page = $params['page'];
  81                 if ( $page > $this->pageCount( $image ) ) {
  82                         return new MediaTransformError( 'thumbnail_error', $width, $height, wfMsg( 'djvu_page_error' ) );
  83                 }
  84
  85                 if ( $flags & self::TRANSFORM_LATER ) {
  86                         return new ThumbnailImage( $image, $dstUrl, $width, $height, $dstPath, $page );
  87                 }
  88
  89                 if ( !wfMkdirParents( dirname( $dstPath ) ) ) {
  90                         return new MediaTransformError( 'thumbnail_error', $width, $height, wfMsg( 'thumbnail_dest_directory' ) );
  91                 }
  92
  93                 # Use a subshell (brackets) to aggregate stderr from both pipeline commands
  94                 # before redirecting it to the overall stdout. This works in both Linux and Windows XP.
  95                 $cmd = '(' . wfEscapeShellArg( $wgDjvuRenderer ) . " -format=ppm -page={$page} -size={$width}x{$height} " .
  96                         wfEscapeShellArg( $srcPath );
  97                 if ( $wgDjvuPostProcessor ) {
  98                         $cmd .= " | {$wgDjvuPostProcessor}";
  99                 }
 100                 $cmd .= ' > ' . wfEscapeShellArg($dstPath) . ') 2>&1';
 101                 wfProfileIn( 'ddjvu' );
 102                 wfDebug( __METHOD__.": $cmd\n" );
 103                 $err = wfShellExec( $cmd, $retval );
 104                 wfProfileOut( 'ddjvu' );
 105
 106                 $removed = $this->removeBadFile( $dstPath, $retval );
 107                 if ( $retval != 0 || $removed ) {
 108                         wfDebugLog( 'thumbnail',
 109                                 sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
 110                                         wfHostname(), $retval, trim($err), $cmd ) );
 111                         return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
 112                 } else {
 113                         return new ThumbnailImage( $image, $dstUrl, $width, $height, $dstPath, $page );
 114                 }
 115         }
 116
 117         /**
 118          * Cache an instance of DjVuImage in an Image object, return that instance
 119          */
 120         function getDjVuImage( $image, $path ) {
 121                 if ( !$image ) {
 122                         $deja = new DjVuImage( $path );
 123                 } elseif ( !isset( $image->dejaImage ) ) {
 124                         $deja = $image->dejaImage = new DjVuImage( $path );
 125                 } else {
 126                         $deja = $image->dejaImage;
 127                 }
 128                 return $deja;
 129         }
 130
 131         /**
 132          * Cache a document tree for the DjVu XML metadata
 133          */
 134         function getMetaTree( $image ) {
 135                 if ( isset( $image->dejaMetaTree ) ) {
 136                         return $image->dejaMetaTree;
 137                 }
 138
 139                 $metadata = $image->getMetadata();
 140                 if ( !$this->isMetadataValid( $image, $metadata ) ) {
 141                         wfDebug( "DjVu XML metadata is invalid or missing, should have been fixed in upgradeRow\n" );
 142                         return false;
 143                 }
 144                 wfProfileIn( __METHOD__ );
 145
 146                 wfSuppressWarnings();
 147                 try {
 148                         $image->dejaMetaTree = new SimpleXMLElement( $metadata );
 149                 } catch( Exception $e ) {
 150                         wfDebug( "Bogus multipage XML metadata on '$image->name'\n" );
 151                         // Set to false rather than null to avoid further attempts
 152                         $image->dejaMetaTree = false;
 153                 }
 154                 wfRestoreWarnings();
 155                 wfProfileOut( __METHOD__ );
 156                 return $image->dejaMetaTree;
 157         }
 158
 159         function getImageSize( $image, $path ) {
 160                 return $this->getDjVuImage( $image, $path )->getImageSize();
 161         }
 162
 163         function getThumbType( $ext, $mime ) {
 164                 global $wgDjvuOutputExtension;
 165                 static $mime;
 166                 if ( !isset( $mime ) ) {
 167                         $magic = MimeMagic::singleton();
 168                         $mime = $magic->guessTypesForExtension( $wgDjvuOutputExtension );
 169                 }
 170                 return array( $wgDjvuOutputExtension, $mime );
 171         }
 172
 173         function getMetadata( $image, $path ) {
 174                 wfDebug( "Getting DjVu metadata for $path\n" );
 175                 return $this->getDjVuImage( $image, $path )->retrieveMetaData();
 176         }
 177
 178         function getMetadataType( $image ) {
 179                 return 'djvuxml';
 180         }
 181
 182         function isMetadataValid( $image, $metadata ) {
 183                 return !empty( $metadata ) && $metadata != serialize(array());
 184         }
 185
 186         function pageCount( $image ) {
 187                 $tree = $this->getMetaTree( $image );
 188                 if ( !$tree ) {
 189                         return false;
 190                 }
 191                 return count( $tree->xpath( '//OBJECT' ) );
 192         }
 193
 194         function getPageDimensions( $image, $page ) {
 195                 $tree = $this->getMetaTree( $image );
 196                 if ( !$tree ) {
 197                         return false;
 198                 }
 199
 200                 $o = $tree->BODY[0]->OBJECT[$page-1];
 201                 if ( $o ) {
 202                         return array(
 203                                 'width' => intval( $o['width'] ),
 204                                 'height' => intval( $o['height'] )
 205                         );
 206                 } else {
 207                         return false;
 208                 }
 209         }
 210 }
 211
 212