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
 147                 if ( $flags & self::TRANSFORM_LATER ) {
 148                         $params = array(
 149                                 'width' => $width,
 150                                 'height' => $height,
 151                                 'page' => $page
 152                         );
 153
 154                         return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
 155                 }
 156
 157                 if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
 158                         return new MediaTransformError(
 159                                 'thumbnail_error',
 160                                 $width,
 161                                 $height,
 162                                 wfMessage( 'thumbnail_dest_directory' )->text()
 163                         );
 164                 }
 165
 166                 // Get local copy source for shell scripts
 167                 // Thumbnail extraction is very inefficient for large files.
 168                 // Provide a way to pool count limit the number of downloaders.
 169                 if ( $image->getSize() >= 1e7 ) { // 10MB
 170                         $work = new PoolCounterWorkViaCallback( 'GetLocalFileCopy', sha1( $image->getName() ),
 171                                 array(
 172                                         'doWork' => function () use ( $image ) {
 173                                                 return $image->getLocalRefPath();
 174                                         }
 175                                 )
 176                         );
 177                         $srcPath = $work->execute();
 178                 } else {
 179                         $srcPath = $image->getLocalRefPath();
 180                 }
 181
 182                 if ( $srcPath === false ) { // Failed to get local copy
 183                         wfDebugLog( 'thumbnail',
 184                                 sprintf( 'Thumbnail failed on %s: could not get local copy of "%s"',
 185                                         wfHostname(), $image->getName() ) );
 186
 187                         return new MediaTransformError( 'thumbnail_error',
 188                                 $params['width'], $params['height'],
 189                                 wfMessage( 'filemissing' )->text()
 190                         );
 191                 }
 192
 193                 # Use a subshell (brackets) to aggregate stderr from both pipeline commands
 194                 # before redirecting it to the overall stdout. This works in both Linux and Windows XP.
 195                 $cmd = '(' . wfEscapeShellArg(
 196                         $wgDjvuRenderer,
 197                         "-format=ppm",
 198                         "-page={$page}",
 199                         "-size={$params['physicalWidth']}x{$params['physicalHeight']}",
 200                         $srcPath );
 201                 if ( $wgDjvuPostProcessor ) {
 202                         $cmd .= " | {$wgDjvuPostProcessor}";
 203                 }
 204                 $cmd .= ' > ' . wfEscapeShellArg( $dstPath ) . ') 2>&1';
 205                 wfDebug( __METHOD__ . ": $cmd\n" );
 206                 $retval = '';
 207                 $err = wfShellExec( $cmd, $retval );
 208
 209                 $removed = $this->removeBadFile( $dstPath, $retval );
 210                 if ( $retval != 0 || $removed ) {
 211                         $this->logErrorForExternalProcess( $retval, $err, $cmd );
 212                         return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
 213                 } else {
 214                         $params = array(
 215                                 'width' => $width,
 216                                 'height' => $height,
 217                                 'page' => $page
 218                         );
 219
 220                         return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
 221                 }
 222         }
 223
 224         /**
 225          * Cache an instance of DjVuImage in an Image object, return that instance
 226          *
 227          * @param File $image
 228          * @param string $path
 229          * @return DjVuImage
 230          */
 231         function getDjVuImage( $image, $path ) {
 232                 if ( !$image ) {
 233                         $deja = new DjVuImage( $path );
 234                 } elseif ( !isset( $image->dejaImage ) ) {
 235                         $deja = $image->dejaImage = new DjVuImage( $path );
 236                 } else {
 237                         $deja = $image->dejaImage;
 238                 }
 239
 240                 return $deja;
 241         }
 242
 243         /**
 244          * Get metadata, unserializing it if neccessary.
 245          *
 246          * @param File $file The DjVu file in question
 247          * @return string XML metadata as a string.
 248          * @throws MWException
 249          */
 250         private function getUnserializedMetadata( File $file ) {
 251                 $metadata = $file->getMetadata();
 252                 if ( substr( $metadata, 0, 3 ) === '<?xml' ) {
 253                         // Old style. Not serialized but instead just a raw string of XML.
 254                         return $metadata;
 255                 }
 256
 257                 wfSuppressWarnings();
 258                 $unser = unserialize( $metadata );
 259                 wfRestoreWarnings();
 260                 if ( is_array( $unser ) ) {
 261                         if ( isset( $unser['error'] ) ) {
 262                                 return false;
 263                         } elseif ( isset( $unser['xml'] ) ) {
 264                                 return $unser['xml'];
 265                         } else {
 266                                 // Should never ever reach here.
 267                                 throw new MWException( "Error unserializing DjVu metadata." );
 268                         }
 269                 }
 270
 271                 // unserialize failed. Guess it wasn't really serialized after all,
 272                 return $metadata;
 273         }
 274
 275         /**
 276          * Cache a document tree for the DjVu XML metadata
 277          * @param File $image
 278          * @param bool $gettext DOCUMENT (Default: false)
 279          * @return bool|SimpleXMLElement
 280          */
 281         function getMetaTree( $image, $gettext = false ) {
 282                 if ( $gettext && isset( $image->djvuTextTree ) ) {
 283                         return $image->djvuTextTree;
 284                 }
 285                 if ( !$gettext && isset( $image->dejaMetaTree ) ) {
 286                         return $image->dejaMetaTree;
 287                 }
 288
 289                 $metadata = $this->getUnserializedMetadata( $image );
 290                 if ( !$this->isMetadataValid( $image, $metadata ) ) {
 291                         wfDebug( "DjVu XML metadata is invalid or missing, should have been fixed in upgradeRow\n" );
 292
 293                         return false;
 294                 }
 295
 296                 wfSuppressWarnings();
 297                 try {
 298                         // Set to false rather than null to avoid further attempts
 299                         $image->dejaMetaTree = false;
 300                         $image->djvuTextTree = false;
 301                         $tree = new SimpleXMLElement( $metadata );
 302                         if ( $tree->getName() == 'mw-djvu' ) {
 303                                 /** @var SimpleXMLElement $b */
 304                                 foreach ( $tree->children() as $b ) {
 305                                         if ( $b->getName() == 'DjVuTxt' ) {
 306                                                 // @todo File::djvuTextTree and File::dejaMetaTree are declared
 307                                                 // dynamically. Add a public File::$data to facilitate this?
 308                                                 $image->djvuTextTree = $b;
 309                                         } elseif ( $b->getName() == 'DjVuXML' ) {
 310                                                 $image->dejaMetaTree = $b;
 311                                         }
 312                                 }
 313                         } else {
 314                                 $image->dejaMetaTree = $tree;
 315                         }
 316                 } catch ( Exception $e ) {
 317                         wfDebug( "Bogus multipage XML metadata on '{$image->getName()}'\n" );
 318                 }
 319                 wfRestoreWarnings();
 320                 if ( $gettext ) {
 321                         return $image->djvuTextTree;
 322                 } else {
 323                         return $image->dejaMetaTree;
 324                 }
 325         }
 326
 327         /**
 328          * @param File $image
 329          * @param string $path
 330          * @return bool|array False on failure
 331          */
 332         function getImageSize( $image, $path ) {
 333                 return $this->getDjVuImage( $image, $path )->getImageSize();
 334         }
 335
 336         function getThumbType( $ext, $mime, $params = null ) {
 337                 global $wgDjvuOutputExtension;
 338                 static $mime;
 339                 if ( !isset( $mime ) ) {
 340                         $magic = MimeMagic::singleton();
 341                         $mime = $magic->guessTypesForExtension( $wgDjvuOutputExtension );
 342                 }
 343
 344                 return array( $wgDjvuOutputExtension, $mime );
 345         }
 346
 347         function getMetadata( $image, $path ) {
 348                 wfDebug( "Getting DjVu metadata for $path\n" );
 349
 350                 $xml = $this->getDjVuImage( $image, $path )->retrieveMetaData();
 351                 if ( $xml === false ) {
 352                         // Special value so that we don't repetitively try and decode a broken file.
 353                         return serialize( array( 'error' => 'Error extracting metadata' ) );
 354                 } else {
 355                         return serialize( array( 'xml' => $xml ) );
 356                 }
 357         }
 358
 359         function getMetadataType( $image ) {
 360                 return 'djvuxml';
 361         }
 362
 363         function isMetadataValid( $image, $metadata ) {
 364                 return !empty( $metadata ) && $metadata != serialize( array() );
 365         }
 366
 367         function pageCount( $image ) {
 368                 $tree = $this->getMetaTree( $image );
 369                 if ( !$tree ) {
 370                         return false;
 371                 }
 372
 373                 return count( $tree->xpath( '//OBJECT' ) );
 374         }
 375
 376         function getPageDimensions( $image, $page ) {
 377                 $tree = $this->getMetaTree( $image );
 378                 if ( !$tree ) {
 379                         return false;
 380                 }
 381
 382                 $o = $tree->BODY[0]->OBJECT[$page - 1];
 383                 if ( $o ) {
 384                         return array(
 385                                 'width' => intval( $o['width'] ),
 386                                 'height' => intval( $o['height'] )
 387                         );
 388                 } else {
 389                         return false;
 390                 }
 391         }
 392
 393         /**
 394          * @param File $image
 395          * @param int $page Page number to get information for
 396          * @return bool|string Page text or false when no text found.
 397          */
 398         function getPageText( $image, $page ) {
 399                 $tree = $this->getMetaTree( $image, true );
 400                 if ( !$tree ) {
 401                         return false;
 402                 }
 403
 404                 $o = $tree->BODY[0]->PAGE[$page - 1];
 405                 if ( $o ) {
 406                         $txt = $o['value'];
 407
 408                         return $txt;
 409                 } else {
 410                         return false;
 411                 }
 412         }
 413 }