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