includes/media/DjVu.php

   1 <?php
   2 /**
   3  * Handler for DjVu images.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 /**
  25  * Handler for DjVu images
  26  *
  27  * @ingroup Media
  28  */
  29 class DjVuHandler extends ImageHandler {
  30         /**
  31          * @return bool
  32          */
  33         function isEnabled() {
  34                 global $wgDjvuRenderer, $wgDjvuDump, $wgDjvuToXML;
  35                 if ( !$wgDjvuRenderer || ( !$wgDjvuDump && !$wgDjvuToXML ) ) {
  36                         wfDebug( "DjVu is disabled, please set \$wgDjvuRenderer and \$wgDjvuDump\n" );
  37
  38                         return false;
  39                 } else {
  40                         return true;
  41                 }
  42         }
  43
  44         /**
  45          * @param File $file
  46          * @return bool
  47          */
  48         function mustRender( $file ) {
  49                 return true;
  50         }
  51
  52         /**
  53          * @param File $file
  54          * @return bool
  55          */
  56         function isMultiPage( $file ) {
  57                 return true;
  58         }
  59
  60         /**
  61          * @return array
  62          */
  63         function getParamMap() {
  64                 return array(
  65                         'img_width' => 'width',
  66                         'img_page' => 'page',
  67                 );
  68         }
  69
  70         /**
  71          * @param string $name
  72          * @param mixed $value
  73          * @return bool
  74          */
  75         function validateParam( $name, $value ) {
  76                 if ( $name === 'page' && trim( $value ) !== (string)intval( $value ) ) {
  77                         // Extra junk on the end of page, probably actually a caption
  78                         // e.g. [[File:Foo.djvu|thumb|Page 3 of the document shows foo]]
  79                         return false;
  80                 }
  81                 if ( in_array( $name, array( 'width', 'height', 'page' ) ) ) {
  82                         if ( $value <= 0 ) {
  83                                 return false;
  84                         } else {
  85                                 return true;
  86                         }
  87                 } else {
  88                         return false;
  89                 }
  90         }
  91
  92         /**
  93          * @param array $params
  94          * @return bool|string
  95          */
  96         function makeParamString( $params ) {
  97                 $page = isset( $params['page'] ) ? $params['page'] : 1;
  98                 if ( !isset( $params['width'] ) ) {
  99                         return false;
 100                 }
 101
 102                 return "page{$page}-{$params['width']}px";
 103         }
 104
 105         /**
 106          * @param string $str
 107          * @return array|bool
 108          */
 109         function parseParamString( $str ) {
 110                 $m = false;
 111                 if ( preg_match( '/^page(\d+)-(\d+)px$/', $str, $m ) ) {
 112                         return array( 'width' => $m[2], 'page' => $m[1] );
 113                 } else {
 114                         return false;
 115                 }
 116         }
 117
 118         /**
 119          * @param array $params
 120          * @return array
 121          */
 122         function getScriptParams( $params ) {
 123                 return array(
 124                         'width' => $params['width'],
 125                         'page' => $params['page'],
 126                 );
 127         }
 128
 129         /**
 130          * @param File $image
 131          * @param string $dstPath
 132          * @param string $dstUrl
 133          * @param array $params
 134          * @param int $flags
 135          * @return MediaTransformError|ThumbnailImage|TransformParameterError
 136          */
 137         function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
 138                 global $wgDjvuRenderer, $wgDjvuPostProcessor;
 139
 140                 if ( !$this->normaliseParams( $image, $params ) ) {
 141                         return new TransformParameterError( $params );
 142                 }
 143                 $width = $params['width'];
 144                 $height = $params['height'];
 145                 $page = $params['page'];
 146                 if ( $page > $this->pageCount( $image ) ) {
 147                         return new MediaTransformError(
 148                                 'thumbnail_error',
 149                                 $width,
 150                                 $height,
 151                                 wfMessage( 'djvu_page_error' )->text()
 152                         );
 153                 }
 154
 155                 if ( $flags & self::TRANSFORM_LATER ) {
 156                         $params = array(
 157                                 'width' => $width,
 158                                 'height' => $height,
 159                                 'page' => $page
 160                         );
 161
 162                         return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
 163                 }
 164
 165                 if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
 166                         return new MediaTransformError(
 167                                 'thumbnail_error',
 168                                 $width,
 169                                 $height,
 170                                 wfMessage( 'thumbnail_dest_directory' )->text()
 171                         );
 172                 }
 173
 174                 // Get local copy source for shell scripts
 175                 // Thumbnail extraction is very inefficient for large files.
 176                 // Provide a way to pool count limit the number of downloaders.
 177                 if ( $image->getSize() >= 1e7 ) { // 10MB
 178                         $work = new PoolCounterWorkViaCallback( 'GetLocalFileCopy', sha1( $image->getName() ),
 179                                 array(
 180                                         'doWork' => function () use ( $image ) {
 181                                                 return $image->getLocalRefPath();
 182                                         }
 183                                 )
 184                         );
 185                         $srcPath = $work->execute();
 186                 } else {
 187                         $srcPath = $image->getLocalRefPath();
 188                 }
 189
 190                 if ( $srcPath === false ) { // Failed to get local copy
 191                         wfDebugLog( 'thumbnail',
 192                                 sprintf( 'Thumbnail failed on %s: could not get local copy of "%s"',
 193                                         wfHostname(), $image->getName() ) );
 194
 195                         return new MediaTransformError( 'thumbnail_error',
 196                                 $params['width'], $params['height'],
 197                                 wfMessage( 'filemissing' )->text()
 198                         );
 199                 }
 200
 201                 # Use a subshell (brackets) to aggregate stderr from both pipeline commands
 202                 # before redirecting it to the overall stdout. This works in both Linux and Windows XP.
 203                 $cmd = '(' . wfEscapeShellArg(
 204                         $wgDjvuRenderer,
 205                         "-format=ppm",
 206                         "-page={$page}",
 207                         "-size={$params['physicalWidth']}x{$params['physicalHeight']}",
 208                         $srcPath );
 209                 if ( $wgDjvuPostProcessor ) {
 210                         $cmd .= " | {$wgDjvuPostProcessor}";
 211                 }
 212                 $cmd .= ' > ' . wfEscapeShellArg( $dstPath ) . ') 2>&1';
 213                 wfDebug( __METHOD__ . ": $cmd\n" );
 214                 $retval = '';
 215                 $err = wfShellExec( $cmd, $retval );
 216
 217                 $removed = $this->removeBadFile( $dstPath, $retval );
 218                 if ( $retval != 0 || $removed ) {
 219                         $this->logErrorForExternalProcess( $retval, $err, $cmd );
 220                         return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
 221                 } else {
 222                         $params = array(
 223                                 'width' => $width,
 224                                 'height' => $height,
 225                                 'page' => $page
 226                         );
 227
 228                         return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
 229                 }
 230         }
 231
 232         /**
 233          * Cache an instance of DjVuImage in an Image object, return that instance
 234          *
 235          * @param File $image
 236          * @param string $path
 237          * @return DjVuImage
 238          */
 239         function getDjVuImage( $image, $path ) {
 240                 if ( !$image ) {
 241                         $deja = new DjVuImage( $path );
 242                 } elseif ( !isset( $image->dejaImage ) ) {
 243                         $deja = $image->dejaImage = new DjVuImage( $path );
 244                 } else {
 245                         $deja = $image->dejaImage;
 246                 }
 247
 248                 return $deja;
 249         }
 250
 251         /**
 252          * Get metadata, unserializing it if neccessary.
 253          *
 254          * @param File $file The DjVu file in question
 255          * @return string XML metadata as a string.
 256          * @throws MWException
 257          */
 258         private function getUnserializedMetadata( File $file ) {
 259                 $metadata = $file->getMetadata();
 260                 if ( substr( $metadata, 0, 3 ) === '<?xml' ) {
 261                         // Old style. Not serialized but instead just a raw string of XML.
 262                         return $metadata;
 263                 }
 264
 265                 wfSuppressWarnings();
 266                 $unser = unserialize( $metadata );
 267                 wfRestoreWarnings();
 268                 if ( is_array( $unser ) ) {
 269                         if ( isset( $unser['error'] ) ) {
 270                                 return false;
 271                         } elseif ( isset( $unser['xml'] ) ) {
 272                                 return $unser['xml'];
 273                         } else {
 274                                 // Should never ever reach here.
 275                                 throw new MWException( "Error unserializing DjVu metadata." );
 276                         }
 277                 }
 278
 279                 // unserialize failed. Guess it wasn't really serialized after all,
 280                 return $metadata;
 281         }
 282
 283         /**
 284          * Cache a document tree for the DjVu XML metadata
 285          * @param File $image
 286          * @param bool $gettext DOCUMENT (Default: false)
 287          * @return bool|SimpleXMLElement
 288          */
 289         function getMetaTree( $image, $gettext = false ) {
 290                 if ( $gettext && isset( $image->djvuTextTree ) ) {
 291                         return $image->djvuTextTree;
 292                 }
 293                 if ( !$gettext && isset( $image->dejaMetaTree ) ) {
 294                         return $image->dejaMetaTree;
 295                 }
 296
 297                 $metadata = $this->getUnserializedMetadata( $image );
 298                 if ( !$this->isMetadataValid( $image, $metadata ) ) {
 299                         wfDebug( "DjVu XML metadata is invalid or missing, should have been fixed in upgradeRow\n" );
 300
 301                         return false;
 302                 }
 303
 304                 wfSuppressWarnings();
 305                 try {
 306                         // Set to false rather than null to avoid further attempts
 307                         $image->dejaMetaTree = false;
 308                         $image->djvuTextTree = false;
 309                         $tree = new SimpleXMLElement( $metadata );
 310                         if ( $tree->getName() == 'mw-djvu' ) {
 311                                 /** @var SimpleXMLElement $b */
 312                                 foreach ( $tree->children() as $b ) {
 313                                         if ( $b->getName() == 'DjVuTxt' ) {
 314                                                 // @todo File::djvuTextTree and File::dejaMetaTree are declared
 315                                                 // dynamically. Add a public File::$data to facilitate this?
 316                                                 $image->djvuTextTree = $b;
 317                                         } elseif ( $b->getName() == 'DjVuXML' ) {
 318                                                 $image->dejaMetaTree = $b;
 319                                         }
 320                                 }
 321                         } else {
 322                                 $image->dejaMetaTree = $tree;
 323                         }
 324                 } catch ( Exception $e ) {
 325                         wfDebug( "Bogus multipage XML metadata on '{$image->getName()}'\n" );
 326                 }
 327                 wfRestoreWarnings();
 328                 if ( $gettext ) {
 329                         return $image->djvuTextTree;
 330                 } else {
 331                         return $image->dejaMetaTree;
 332                 }
 333         }
 334
 335         /**
 336          * @param File $image
 337          * @param string $path
 338          * @return bool|array False on failure
 339          */
 340         function getImageSize( $image, $path ) {
 341                 return $this->getDjVuImage( $image, $path )->getImageSize();
 342         }
 343
 344         function getThumbType( $ext, $mime, $params = null ) {
 345                 global $wgDjvuOutputExtension;
 346                 static $mime;
 347                 if ( !isset( $mime ) ) {
 348                         $magic = MimeMagic::singleton();
 349                         $mime = $magic->guessTypesForExtension( $wgDjvuOutputExtension );
 350                 }
 351
 352                 return array( $wgDjvuOutputExtension, $mime );
 353         }
 354
 355         function getMetadata( $image, $path ) {
 356                 wfDebug( "Getting DjVu metadata for $path\n" );
 357
 358                 $xml = $this->getDjVuImage( $image, $path )->retrieveMetaData();
 359                 if ( $xml === false ) {
 360                         // Special value so that we don't repetitively try and decode a broken file.
 361                         return serialize( array( 'error' => 'Error extracting metadata' ) );
 362                 } else {
 363                         return serialize( array( 'xml' => $xml ) );
 364                 }
 365         }
 366
 367         function getMetadataType( $image ) {
 368                 return 'djvuxml';
 369         }
 370
 371         function isMetadataValid( $image, $metadata ) {
 372                 return !empty( $metadata ) && $metadata != serialize( array() );
 373         }
 374
 375         function pageCount( $image ) {
 376                 $tree = $this->getMetaTree( $image );
 377                 if ( !$tree ) {
 378                         return false;
 379                 }
 380
 381                 return count( $tree->xpath( '//OBJECT' ) );
 382         }
 383
 384         function getPageDimensions( $image, $page ) {
 385                 $tree = $this->getMetaTree( $image );
 386                 if ( !$tree ) {
 387                         return false;
 388                 }
 389
 390                 $o = $tree->BODY[0]->OBJECT[$page - 1];
 391                 if ( $o ) {
 392                         return array(
 393                                 'width' => intval( $o['width'] ),
 394                                 'height' => intval( $o['height'] )
 395                         );
 396                 } else {
 397                         return false;
 398                 }
 399         }
 400
 401         /**
 402          * @param File $image
 403          * @param int $page Page number to get information for
 404          * @return bool|string Page text or false when no text found.
 405          */
 406         function getPageText( $image, $page ) {
 407                 $tree = $this->getMetaTree( $image, true );
 408                 if ( !$tree ) {
 409                         return false;
 410                 }
 411
 412                 $o = $tree->BODY[0]->PAGE[$page - 1];
 413                 if ( $o ) {
 414                         $txt = $o['value'];
 415
 416                         return $txt;
 417                 } else {
 418                         return false;
 419                 }
 420         }
 421 }