includes/media/DjVuImage.php

   1 <?php
   2 /**
   3  * DjVu image handler.
   4  *
   5  * Copyright © 2006 Brion Vibber <brion@pobox.com>
   6  * https://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  * @ingroup Media
  25  */
  26
  27 use MediaWiki\Shell\Shell;
  28
  29 /**
  30  * Support for detecting/validating DjVu image files and getting
  31  * some basic file metadata (resolution etc)
  32  *
  33  * File format docs are available in source package for DjVuLibre:
  34  * http://djvulibre.djvuzone.org/
  35  *
  36  * @ingroup Media
  37  */
  38 class DjVuImage {
  39
  40         /**
  41          * Memory limit for the DjVu description software
  42          */
  43         const DJVUTXT_MEMORY_LIMIT = 300000;
  44
  45         /**
  46          * @param string $filename The DjVu file name.
  47          */
  48         function __construct( $filename ) {
  49                 $this->mFilename = $filename;
  50         }
  51
  52         /**
  53          * Check if the given file is indeed a valid DjVu image file
  54          * @return bool
  55          */
  56         public function isValid() {
  57                 $info = $this->getInfo();
  58
  59                 return $info !== false;
  60         }
  61
  62         /**
  63          * Return data in the style of getimagesize()
  64          * @return array|bool Array or false on failure
  65          */
  66         public function getImageSize() {
  67                 $data = $this->getInfo();
  68
  69                 if ( $data !== false ) {
  70                         $width = $data['width'];
  71                         $height = $data['height'];
  72
  73                         return [ $width, $height, 'DjVu',
  74                                 "width=\"$width\" height=\"$height\"" ];
  75                 }
  76
  77                 return false;
  78         }
  79
  80         // ---------
  81
  82         /**
  83          * For debugging; dump the IFF chunk structure
  84          */
  85         function dump() {
  86                 $file = fopen( $this->mFilename, 'rb' );
  87                 $header = fread( $file, 12 );
  88                 $arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
  89                 $chunk = $arr['chunk'];
  90                 $chunkLength = $arr['chunkLength'];
  91                 echo "$chunk $chunkLength\n";
  92                 $this->dumpForm( $file, $chunkLength, 1 );
  93                 fclose( $file );
  94         }
  95
  96         private function dumpForm( $file, $length, $indent ) {
  97                 $start = ftell( $file );
  98                 $secondary = fread( $file, 4 );
  99                 echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
 100                 while ( ftell( $file ) - $start < $length ) {
 101                         $chunkHeader = fread( $file, 8 );
 102                         if ( $chunkHeader == '' ) {
 103                                 break;
 104                         }
 105                         $arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
 106                         $chunk = $arr['chunk'];
 107                         $chunkLength = $arr['chunkLength'];
 108                         echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
 109
 110                         if ( $chunk == 'FORM' ) {
 111                                 $this->dumpForm( $file, $chunkLength, $indent + 1 );
 112                         } else {
 113                                 fseek( $file, $chunkLength, SEEK_CUR );
 114                                 if ( $chunkLength & 1 ) {
 115                                         // Padding byte between chunks
 116                                         fseek( $file, 1, SEEK_CUR );
 117                                 }
 118                         }
 119                 }
 120         }
 121
 122         function getInfo() {
 123                 Wikimedia\suppressWarnings();
 124                 $file = fopen( $this->mFilename, 'rb' );
 125                 Wikimedia\restoreWarnings();
 126                 if ( $file === false ) {
 127                         wfDebug( __METHOD__ . ": missing or failed file read\n" );
 128
 129                         return false;
 130                 }
 131
 132                 $header = fread( $file, 16 );
 133                 $info = false;
 134
 135                 if ( strlen( $header ) < 16 ) {
 136                         wfDebug( __METHOD__ . ": too short file header\n" );
 137                 } else {
 138                         $arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
 139
 140                         $subtype = $arr['subtype'];
 141                         if ( $arr['magic'] != 'AT&T' ) {
 142                                 wfDebug( __METHOD__ . ": not a DjVu file\n" );
 143                         } elseif ( $subtype == 'DJVU' ) {
 144                                 // Single-page document
 145                                 $info = $this->getPageInfo( $file );
 146                         } elseif ( $subtype == 'DJVM' ) {
 147                                 // Multi-page document
 148                                 $info = $this->getMultiPageInfo( $file, $arr['formLength'] );
 149                         } else {
 150                                 wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'\n" );
 151                         }
 152                 }
 153                 fclose( $file );
 154
 155                 return $info;
 156         }
 157
 158         private function readChunk( $file ) {
 159                 $header = fread( $file, 8 );
 160                 if ( strlen( $header ) < 8 ) {
 161                         return [ false, 0 ];
 162                 } else {
 163                         $arr = unpack( 'a4chunk/Nlength', $header );
 164
 165                         return [ $arr['chunk'], $arr['length'] ];
 166                 }
 167         }
 168
 169         private function skipChunk( $file, $chunkLength ) {
 170                 fseek( $file, $chunkLength, SEEK_CUR );
 171
 172                 if ( ( $chunkLength & 1 ) && !feof( $file ) ) {
 173                         // padding byte
 174                         fseek( $file, 1, SEEK_CUR );
 175                 }
 176         }
 177
 178         private function getMultiPageInfo( $file, $formLength ) {
 179                 // For now, we'll just look for the first page in the file
 180                 // and report its information, hoping others are the same size.
 181                 $start = ftell( $file );
 182                 do {
 183                         list( $chunk, $length ) = $this->readChunk( $file );
 184                         if ( !$chunk ) {
 185                                 break;
 186                         }
 187
 188                         if ( $chunk == 'FORM' ) {
 189                                 $subtype = fread( $file, 4 );
 190                                 if ( $subtype == 'DJVU' ) {
 191                                         wfDebug( __METHOD__ . ": found first subpage\n" );
 192
 193                                         return $this->getPageInfo( $file );
 194                                 }
 195                                 $this->skipChunk( $file, $length - 4 );
 196                         } else {
 197                                 wfDebug( __METHOD__ . ": skipping '$chunk' chunk\n" );
 198                                 $this->skipChunk( $file, $length );
 199                         }
 200                 } while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
 201
 202                 wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages\n" );
 203
 204                 return false;
 205         }
 206
 207         private function getPageInfo( $file ) {
 208                 list( $chunk, $length ) = $this->readChunk( $file );
 209                 if ( $chunk != 'INFO' ) {
 210                         wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'\n" );
 211
 212                         return false;
 213                 }
 214
 215                 if ( $length < 9 ) {
 216                         wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length\n" );
 217
 218                         return false;
 219                 }
 220                 $data = fread( $file, $length );
 221                 if ( strlen( $data ) < $length ) {
 222                         wfDebug( __METHOD__ . ": INFO chunk cut off\n" );
 223
 224                         return false;
 225                 }
 226
 227                 $arr = unpack(
 228                         'nwidth/' .
 229                         'nheight/' .
 230                         'Cminor/' .
 231                         'Cmajor/' .
 232                         'vresolution/' .
 233                         'Cgamma', $data );
 234
 235                 # Newer files have rotation info in byte 10, but we don't use it yet.
 236
 237                 return [
 238                         'width' => $arr['width'],
 239                         'height' => $arr['height'],
 240                         'version' => "{$arr['major']}.{$arr['minor']}",
 241                         'resolution' => $arr['resolution'],
 242                         'gamma' => $arr['gamma'] / 10.0 ];
 243         }
 244
 245         /**
 246          * Return an XML string describing the DjVu image
 247          * @return string|bool
 248          */
 249         function retrieveMetaData() {
 250                 global $wgDjvuToXML, $wgDjvuDump, $wgDjvuTxt;
 251
 252                 if ( !$this->isValid() ) {
 253                         return false;
 254                 }
 255
 256                 if ( isset( $wgDjvuDump ) ) {
 257                         # djvudump is faster as of version 3.5
 258                         # https://sourceforge.net/p/djvu/bugs/71/
 259                         $cmd = Shell::escape( $wgDjvuDump ) . ' ' . Shell::escape( $this->mFilename );
 260                         $dump = wfShellExec( $cmd );
 261                         $xml = $this->convertDumpToXML( $dump );
 262                 } elseif ( isset( $wgDjvuToXML ) ) {
 263                         $cmd = Shell::escape( $wgDjvuToXML ) . ' --without-anno --without-text ' .
 264                                 Shell::escape( $this->mFilename );
 265                         $xml = wfShellExec( $cmd );
 266                 } else {
 267                         $xml = null;
 268                 }
 269                 # Text layer
 270                 if ( isset( $wgDjvuTxt ) ) {
 271                         $cmd = Shell::escape( $wgDjvuTxt ) . ' --detail=page ' . Shell::escape( $this->mFilename );
 272                         wfDebug( __METHOD__ . ": $cmd\n" );
 273                         $retval = '';
 274                         $txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
 275                         if ( $retval == 0 ) {
 276                                 # Strip some control characters
 277                                 $txt = preg_replace( "/[\013\035\037]/", "", $txt );
 278                                 $reg = <<<EOR
 279                                         /\(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
 280                                         ((?>    # Text to match is composed of atoms of either:
 281                                                 \\\\. # - any escaped character
 282                                                 |     # - any character different from " and \
 283                                                 [^"\\\\]+
 284                                         )*?)
 285                                         "\s*\)
 286                                         | # Or page can be empty ; in this case, djvutxt dumps ()
 287                                         \(\s*()\)/sx
 288 EOR;
 289                                 $txt = preg_replace_callback( $reg, [ $this, 'pageTextCallback' ], $txt );
 290                                 $txt = "<DjVuTxt>\n<HEAD></HEAD>\n<BODY>\n" . $txt . "</BODY>\n</DjVuTxt>\n";
 291                                 $xml = preg_replace( "/<DjVuXML>/", "<mw-djvu><DjVuXML>", $xml, 1 ) .
 292                                         $txt .
 293                                         '</mw-djvu>';
 294                         }
 295                 }
 296
 297                 return $xml;
 298         }
 299
 300         function pageTextCallback( $matches ) {
 301                 # Get rid of invalid UTF-8, strip control characters
 302                 $val = htmlspecialchars( UtfNormal\Validator::cleanUp( stripcslashes( $matches[1] ) ) );
 303                 $val = str_replace( [ "\n", '�' ], [ '&#10;', '' ], $val );
 304                 return '<PAGE value="' . $val . '" />';
 305         }
 306
 307         /**
 308          * Hack to temporarily work around djvutoxml bug
 309          * @param string $dump
 310          * @return string
 311          */
 312         function convertDumpToXML( $dump ) {
 313                 if ( strval( $dump ) == '' ) {
 314                         return false;
 315                 }
 316
 317                 $xml = <<<EOT
 318 <?xml version="1.0" ?>
 319 <!DOCTYPE DjVuXML PUBLIC "-//W3C//DTD DjVuXML 1.1//EN" "pubtext/DjVuXML-s.dtd">
 320 <DjVuXML>
 321 <HEAD></HEAD>
 322 <BODY>
 323 EOT;
 324
 325                 $dump = str_replace( "\r", '', $dump );
 326                 $line = strtok( $dump, "\n" );
 327                 $m = false;
 328                 $good = false;
 329                 if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
 330                         # Single-page
 331                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 332                                 $good = true;
 333                         } else {
 334                                 return false;
 335                         }
 336                 } elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
 337                         # Multi-page
 338                         $parentLevel = strlen( $m[1] );
 339                         # Find DIRM
 340                         $line = strtok( "\n" );
 341                         while ( $line !== false ) {
 342                                 $childLevel = strspn( $line, ' ' );
 343                                 if ( $childLevel <= $parentLevel ) {
 344                                         # End of chunk
 345                                         break;
 346                                 }
 347
 348                                 if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
 349                                         wfDebug( "Indirect multi-page DjVu document, bad for server!\n" );
 350
 351                                         return false;
 352                                 }
 353                                 if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
 354                                         # Found page
 355                                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 356                                                 $good = true;
 357                                         } else {
 358                                                 return false;
 359                                         }
 360                                 }
 361                                 $line = strtok( "\n" );
 362                         }
 363                 }
 364                 if ( !$good ) {
 365                         return false;
 366                 }
 367
 368                 $xml .= "</BODY>\n</DjVuXML>\n";
 369
 370                 return $xml;
 371         }
 372
 373         function parseFormDjvu( $line, &$xml ) {
 374                 $parentLevel = strspn( $line, ' ' );
 375                 $line = strtok( "\n" );
 376
 377                 # Find INFO
 378                 while ( $line !== false ) {
 379                         $childLevel = strspn( $line, ' ' );
 380                         if ( $childLevel <= $parentLevel ) {
 381                                 # End of chunk
 382                                 break;
 383                         }
 384
 385                         if ( preg_match(
 386                                 '/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
 387                                 $line,
 388                                 $m
 389                         ) ) {
 390                                 $xml .= Xml::tags(
 391                                         'OBJECT',
 392                                         [
 393                                                 # 'data' => '',
 394                                                 # 'type' => 'image/x.djvu',
 395                                                 'height' => $m[2],
 396                                                 'width' => $m[1],
 397                                                 # 'usemap' => '',
 398                                         ],
 399                                         "\n" .
 400                                                 Xml::element( 'PARAM', [ 'name' => 'DPI', 'value' => $m[3] ] ) . "\n" .
 401                                                 Xml::element( 'PARAM', [ 'name' => 'GAMMA', 'value' => $m[4] ] ) . "\n"
 402                                 ) . "\n";
 403
 404                                 return true;
 405                         }
 406                         $line = strtok( "\n" );
 407                 }
 408
 409                 # Not found
 410                 return false;
 411         }
 412 }