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