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          * @const DJVUTXT_MEMORY_LIMIT Memory limit for the DjVu description software
  41          */
  42         const DJVUTXT_MEMORY_LIMIT = 300000;
  43
  44         /**
  45          * @param string $filename The DjVu file name.
  46          */
  47         function __construct( $filename ) {
  48                 $this->mFilename = $filename;
  49         }
  50
  51         /**
  52          * Check if the given file is indeed a valid DjVu image file
  53          * @return bool
  54          */
  55         public function isValid() {
  56                 $info = $this->getInfo();
  57
  58                 return $info !== false;
  59         }
  60
  61         /**
  62          * Return data in the style of getimagesize()
  63          * @return array|bool Array or false on failure
  64          */
  65         public function getImageSize() {
  66                 $data = $this->getInfo();
  67
  68                 if ( $data !== false ) {
  69                         $width = $data['width'];
  70                         $height = $data['height'];
  71
  72                         return [ $width, $height, 'DjVu',
  73                                 "width=\"$width\" height=\"$height\"" ];
  74                 }
  75
  76                 return false;
  77         }
  78
  79         // ---------
  80
  81         /**
  82          * For debugging; dump the IFF chunk structure
  83          */
  84         function dump() {
  85                 $file = fopen( $this->mFilename, 'rb' );
  86                 $header = fread( $file, 12 );
  87                 $arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
  88                 $chunk = $arr['chunk'];
  89                 $chunkLength = $arr['chunkLength'];
  90                 echo "$chunk $chunkLength\n";
  91                 $this->dumpForm( $file, $chunkLength, 1 );
  92                 fclose( $file );
  93         }
  94
  95         private function dumpForm( $file, $length, $indent ) {
  96                 $start = ftell( $file );
  97                 $secondary = fread( $file, 4 );
  98                 echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
  99                 while ( ftell( $file ) - $start < $length ) {
 100                         $chunkHeader = fread( $file, 8 );
 101                         if ( $chunkHeader == '' ) {
 102                                 break;
 103                         }
 104                         $arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
 105                         $chunk = $arr['chunk'];
 106                         $chunkLength = $arr['chunkLength'];
 107                         echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
 108
 109                         if ( $chunk == 'FORM' ) {
 110                                 $this->dumpForm( $file, $chunkLength, $indent + 1 );
 111                         } else {
 112                                 fseek( $file, $chunkLength, SEEK_CUR );
 113                                 if ( ( $chunkLength & 1 ) == 1 ) {
 114                                         // Padding byte between chunks
 115                                         fseek( $file, 1, SEEK_CUR );
 116                                 }
 117                         }
 118                 }
 119         }
 120
 121         function getInfo() {
 122                 Wikimedia\suppressWarnings();
 123                 $file = fopen( $this->mFilename, 'rb' );
 124                 Wikimedia\restoreWarnings();
 125                 if ( $file === false ) {
 126                         wfDebug( __METHOD__ . ": missing or failed file read\n" );
 127
 128                         return false;
 129                 }
 130
 131                 $header = fread( $file, 16 );
 132                 $info = false;
 133
 134                 if ( strlen( $header ) < 16 ) {
 135                         wfDebug( __METHOD__ . ": too short file header\n" );
 136                 } else {
 137                         $arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
 138
 139                         $subtype = $arr['subtype'];
 140                         if ( $arr['magic'] != 'AT&T' ) {
 141                                 wfDebug( __METHOD__ . ": not a DjVu file\n" );
 142                         } elseif ( $subtype == 'DJVU' ) {
 143                                 // Single-page document
 144                                 $info = $this->getPageInfo( $file );
 145                         } elseif ( $subtype == 'DJVM' ) {
 146                                 // Multi-page document
 147                                 $info = $this->getMultiPageInfo( $file, $arr['formLength'] );
 148                         } else {
 149                                 wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'\n" );
 150                         }
 151                 }
 152                 fclose( $file );
 153
 154                 return $info;
 155         }
 156
 157         private function readChunk( $file ) {
 158                 $header = fread( $file, 8 );
 159                 if ( strlen( $header ) < 8 ) {
 160                         return [ false, 0 ];
 161                 } else {
 162                         $arr = unpack( 'a4chunk/Nlength', $header );
 163
 164                         return [ $arr['chunk'], $arr['length'] ];
 165                 }
 166         }
 167
 168         private function skipChunk( $file, $chunkLength ) {
 169                 fseek( $file, $chunkLength, SEEK_CUR );
 170
 171                 if ( ( $chunkLength & 0x01 ) == 1 && !feof( $file ) ) {
 172                         // padding byte
 173                         fseek( $file, 1, SEEK_CUR );
 174                 }
 175         }
 176
 177         private function getMultiPageInfo( $file, $formLength ) {
 178                 // For now, we'll just look for the first page in the file
 179                 // and report its information, hoping others are the same size.
 180                 $start = ftell( $file );
 181                 do {
 182                         list( $chunk, $length ) = $this->readChunk( $file );
 183                         if ( !$chunk ) {
 184                                 break;
 185                         }
 186
 187                         if ( $chunk == 'FORM' ) {
 188                                 $subtype = fread( $file, 4 );
 189                                 if ( $subtype == 'DJVU' ) {
 190                                         wfDebug( __METHOD__ . ": found first subpage\n" );
 191
 192                                         return $this->getPageInfo( $file );
 193                                 }
 194                                 $this->skipChunk( $file, $length - 4 );
 195                         } else {
 196                                 wfDebug( __METHOD__ . ": skipping '$chunk' chunk\n" );
 197                                 $this->skipChunk( $file, $length );
 198                         }
 199                 } while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
 200
 201                 wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages\n" );
 202
 203                 return false;
 204         }
 205
 206         private function getPageInfo( $file ) {
 207                 list( $chunk, $length ) = $this->readChunk( $file );
 208                 if ( $chunk != 'INFO' ) {
 209                         wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'\n" );
 210
 211                         return false;
 212                 }
 213
 214                 if ( $length < 9 ) {
 215                         wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length\n" );
 216
 217                         return false;
 218                 }
 219                 $data = fread( $file, $length );
 220                 if ( strlen( $data ) < $length ) {
 221                         wfDebug( __METHOD__ . ": INFO chunk cut off\n" );
 222
 223                         return false;
 224                 }
 225
 226                 $arr = unpack(
 227                         'nwidth/' .
 228                         'nheight/' .
 229                         'Cminor/' .
 230                         'Cmajor/' .
 231                         'vresolution/' .
 232                         'Cgamma', $data );
 233
 234                 # Newer files have rotation info in byte 10, but we don't use it yet.
 235
 236                 return [
 237                         'width' => $arr['width'],
 238                         'height' => $arr['height'],
 239                         'version' => "{$arr['major']}.{$arr['minor']}",
 240                         'resolution' => $arr['resolution'],
 241                         'gamma' => $arr['gamma'] / 10.0 ];
 242         }
 243
 244         /**
 245          * Return an XML string describing the DjVu image
 246          * @return string|bool
 247          */
 248         function retrieveMetaData() {
 249                 global $wgDjvuToXML, $wgDjvuDump, $wgDjvuTxt;
 250
 251                 if ( !$this->isValid() ) {
 252                         return false;
 253                 }
 254
 255                 if ( isset( $wgDjvuDump ) ) {
 256                         # djvudump is faster as of version 3.5
 257                         # https://sourceforge.net/p/djvu/bugs/71/
 258                         $cmd = Shell::escape( $wgDjvuDump ) . ' ' . Shell::escape( $this->mFilename );
 259                         $dump = wfShellExec( $cmd );
 260                         $xml = $this->convertDumpToXML( $dump );
 261                 } elseif ( isset( $wgDjvuToXML ) ) {
 262                         $cmd = Shell::escape( $wgDjvuToXML ) . ' --without-anno --without-text ' .
 263                                 Shell::escape( $this->mFilename );
 264                         $xml = wfShellExec( $cmd );
 265                 } else {
 266                         $xml = null;
 267                 }
 268                 # Text layer
 269                 if ( isset( $wgDjvuTxt ) ) {
 270                         $cmd = Shell::escape( $wgDjvuTxt ) . ' --detail=page ' . Shell::escape( $this->mFilename );
 271                         wfDebug( __METHOD__ . ": $cmd\n" );
 272                         $retval = '';
 273                         $txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
 274                         if ( $retval == 0 ) {
 275                                 # Strip some control characters
 276                                 $txt = preg_replace( "/[\013\035\037]/", "", $txt );
 277                                 $reg = <<<EOR
 278                                         /\(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
 279                                         ((?>    # Text to match is composed of atoms of either:
 280                                                 \\\\. # - any escaped character
 281                                                 |     # - any character different from " and \
 282                                                 [^"\\\\]+
 283                                         )*?)
 284                                         "\s*\)
 285                                         | # Or page can be empty ; in this case, djvutxt dumps ()
 286                                         \(\s*()\)/sx
 287 EOR;
 288                                 $txt = preg_replace_callback( $reg, [ $this, 'pageTextCallback' ], $txt );
 289                                 $txt = "<DjVuTxt>\n<HEAD></HEAD>\n<BODY>\n" . $txt . "</BODY>\n</DjVuTxt>\n";
 290                                 $xml = preg_replace( "/<DjVuXML>/", "<mw-djvu><DjVuXML>", $xml, 1 ) .
 291                                         $txt .
 292                                         '</mw-djvu>';
 293                         }
 294                 }
 295
 296                 return $xml;
 297         }
 298
 299         function pageTextCallback( $matches ) {
 300                 # Get rid of invalid UTF-8, strip control characters
 301                 $val = htmlspecialchars( UtfNormal\Validator::cleanUp( stripcslashes( $matches[1] ) ) );
 302                 $val = str_replace( [ "\n", '�' ], [ '&#10;', '' ], $val );
 303                 return '<PAGE value="' . $val . '" />';
 304         }
 305
 306         /**
 307          * Hack to temporarily work around djvutoxml bug
 308          * @param string $dump
 309          * @return string
 310          */
 311         function convertDumpToXML( $dump ) {
 312                 if ( strval( $dump ) == '' ) {
 313                         return false;
 314                 }
 315
 316                 $xml = <<<EOT
 317 <?xml version="1.0" ?>
 318 <!DOCTYPE DjVuXML PUBLIC "-//W3C//DTD DjVuXML 1.1//EN" "pubtext/DjVuXML-s.dtd">
 319 <DjVuXML>
 320 <HEAD></HEAD>
 321 <BODY>
 322 EOT;
 323
 324                 $dump = str_replace( "\r", '', $dump );
 325                 $line = strtok( $dump, "\n" );
 326                 $m = false;
 327                 $good = false;
 328                 if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
 329                         # Single-page
 330                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 331                                 $good = true;
 332                         } else {
 333                                 return false;
 334                         }
 335                 } elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
 336                         # Multi-page
 337                         $parentLevel = strlen( $m[1] );
 338                         # Find DIRM
 339                         $line = strtok( "\n" );
 340                         while ( $line !== false ) {
 341                                 $childLevel = strspn( $line, ' ' );
 342                                 if ( $childLevel <= $parentLevel ) {
 343                                         # End of chunk
 344                                         break;
 345                                 }
 346
 347                                 if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
 348                                         wfDebug( "Indirect multi-page DjVu document, bad for server!\n" );
 349
 350                                         return false;
 351                                 }
 352                                 if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
 353                                         # Found page
 354                                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 355                                                 $good = true;
 356                                         } else {
 357                                                 return false;
 358                                         }
 359                                 }
 360                                 $line = strtok( "\n" );
 361                         }
 362                 }
 363                 if ( !$good ) {
 364                         return false;
 365                 }
 366
 367                 $xml .= "</BODY>\n</DjVuXML>\n";
 368
 369                 return $xml;
 370         }
 371
 372         function parseFormDjvu( $line, &$xml ) {
 373                 $parentLevel = strspn( $line, ' ' );
 374                 $line = strtok( "\n" );
 375
 376                 # Find INFO
 377                 while ( $line !== false ) {
 378                         $childLevel = strspn( $line, ' ' );
 379                         if ( $childLevel <= $parentLevel ) {
 380                                 # End of chunk
 381                                 break;
 382                         }
 383
 384                         if ( preg_match(
 385                                 '/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
 386                                 $line,
 387                                 $m
 388                         ) ) {
 389                                 $xml .= Xml::tags(
 390                                         'OBJECT',
 391                                         [
 392                                                 # 'data' => '',
 393                                                 # 'type' => 'image/x.djvu',
 394                                                 'height' => $m[2],
 395                                                 'width' => $m[1],
 396                                                 # 'usemap' => '',
 397                                         ],
 398                                         "\n" .
 399                                                 Xml::element( 'PARAM', [ 'name' => 'DPI', 'value' => $m[3] ] ) . "\n" .
 400                                                 Xml::element( 'PARAM', [ 'name' => 'GAMMA', 'value' => $m[4] ] ) . "\n"
 401                                 ) . "\n";
 402
 403                                 return true;
 404                         }
 405                         $line = strtok( "\n" );
 406                 }
 407
 408                 # Not found
 409                 return false;
 410         }
 411 }