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         /** @var string */
  46         private $mFilename;
  47
  48         /**
  49          * @param string $filename The DjVu file name.
  50          */
  51         function __construct( $filename ) {
  52                 $this->mFilename = $filename;
  53         }
  54
  55         /**
  56          * Check if the given file is indeed a valid DjVu image file
  57          * @return bool
  58          */
  59         public function isValid() {
  60                 $info = $this->getInfo();
  61
  62                 return $info !== false;
  63         }
  64
  65         /**
  66          * Return data in the style of getimagesize()
  67          * @return array|false Array or false on failure
  68          */
  69         public function getImageSize() {
  70                 $data = $this->getInfo();
  71
  72                 if ( $data !== false ) {
  73                         $width = $data['width'];
  74                         $height = $data['height'];
  75
  76                         return [ $width, $height, 'DjVu',
  77                                 "width=\"$width\" height=\"$height\"" ];
  78                 }
  79
  80                 return false;
  81         }
  82
  83         // ---------
  84
  85         /**
  86          * For debugging; dump the IFF chunk structure
  87          */
  88         function dump() {
  89                 $file = fopen( $this->mFilename, 'rb' );
  90                 $header = fread( $file, 12 );
  91                 $arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
  92                 $chunk = $arr['chunk'];
  93                 $chunkLength = $arr['chunkLength'];
  94                 echo "$chunk $chunkLength\n";
  95                 $this->dumpForm( $file, $chunkLength, 1 );
  96                 fclose( $file );
  97         }
  98
  99         private function dumpForm( $file, $length, $indent ) {
 100                 $start = ftell( $file );
 101                 $secondary = fread( $file, 4 );
 102                 echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
 103                 while ( ftell( $file ) - $start < $length ) {
 104                         $chunkHeader = fread( $file, 8 );
 105                         if ( $chunkHeader == '' ) {
 106                                 break;
 107                         }
 108                         $arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
 109                         $chunk = $arr['chunk'];
 110                         $chunkLength = $arr['chunkLength'];
 111                         echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
 112
 113                         if ( $chunk == 'FORM' ) {
 114                                 $this->dumpForm( $file, $chunkLength, $indent + 1 );
 115                         } else {
 116                                 fseek( $file, $chunkLength, SEEK_CUR );
 117                                 if ( $chunkLength & 1 ) {
 118                                         // Padding byte between chunks
 119                                         fseek( $file, 1, SEEK_CUR );
 120                                 }
 121                         }
 122                 }
 123         }
 124
 125         function getInfo() {
 126                 Wikimedia\suppressWarnings();
 127                 $file = fopen( $this->mFilename, 'rb' );
 128                 Wikimedia\restoreWarnings();
 129                 if ( $file === false ) {
 130                         wfDebug( __METHOD__ . ": missing or failed file read\n" );
 131
 132                         return false;
 133                 }
 134
 135                 $header = fread( $file, 16 );
 136                 $info = false;
 137
 138                 if ( strlen( $header ) < 16 ) {
 139                         wfDebug( __METHOD__ . ": too short file header\n" );
 140                 } else {
 141                         $arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
 142
 143                         $subtype = $arr['subtype'];
 144                         if ( $arr['magic'] != 'AT&T' ) {
 145                                 wfDebug( __METHOD__ . ": not a DjVu file\n" );
 146                         } elseif ( $subtype == 'DJVU' ) {
 147                                 // Single-page document
 148                                 $info = $this->getPageInfo( $file );
 149                         } elseif ( $subtype == 'DJVM' ) {
 150                                 // Multi-page document
 151                                 $info = $this->getMultiPageInfo( $file, $arr['formLength'] );
 152                         } else {
 153                                 wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'\n" );
 154                         }
 155                 }
 156                 fclose( $file );
 157
 158                 return $info;
 159         }
 160
 161         private function readChunk( $file ) {
 162                 $header = fread( $file, 8 );
 163                 if ( strlen( $header ) < 8 ) {
 164                         return [ false, 0 ];
 165                 } else {
 166                         $arr = unpack( 'a4chunk/Nlength', $header );
 167
 168                         return [ $arr['chunk'], $arr['length'] ];
 169                 }
 170         }
 171
 172         private function skipChunk( $file, $chunkLength ) {
 173                 fseek( $file, $chunkLength, SEEK_CUR );
 174
 175                 if ( ( $chunkLength & 1 ) && !feof( $file ) ) {
 176                         // padding byte
 177                         fseek( $file, 1, SEEK_CUR );
 178                 }
 179         }
 180
 181         private function getMultiPageInfo( $file, $formLength ) {
 182                 // For now, we'll just look for the first page in the file
 183                 // and report its information, hoping others are the same size.
 184                 $start = ftell( $file );
 185                 do {
 186                         list( $chunk, $length ) = $this->readChunk( $file );
 187                         if ( !$chunk ) {
 188                                 break;
 189                         }
 190
 191                         if ( $chunk == 'FORM' ) {
 192                                 $subtype = fread( $file, 4 );
 193                                 if ( $subtype == 'DJVU' ) {
 194                                         wfDebug( __METHOD__ . ": found first subpage\n" );
 195
 196                                         return $this->getPageInfo( $file );
 197                                 }
 198                                 $this->skipChunk( $file, $length - 4 );
 199                         } else {
 200                                 wfDebug( __METHOD__ . ": skipping '$chunk' chunk\n" );
 201                                 $this->skipChunk( $file, $length );
 202                         }
 203                 } while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
 204
 205                 wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages\n" );
 206
 207                 return false;
 208         }
 209
 210         private function getPageInfo( $file ) {
 211                 list( $chunk, $length ) = $this->readChunk( $file );
 212                 if ( $chunk != 'INFO' ) {
 213                         wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'\n" );
 214
 215                         return false;
 216                 }
 217
 218                 if ( $length < 9 ) {
 219                         wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length\n" );
 220
 221                         return false;
 222                 }
 223                 $data = fread( $file, $length );
 224                 if ( strlen( $data ) < $length ) {
 225                         wfDebug( __METHOD__ . ": INFO chunk cut off\n" );
 226
 227                         return false;
 228                 }
 229
 230                 $arr = unpack(
 231                         'nwidth/' .
 232                         'nheight/' .
 233                         'Cminor/' .
 234                         'Cmajor/' .
 235                         'vresolution/' .
 236                         'Cgamma', $data );
 237
 238                 # Newer files have rotation info in byte 10, but we don't use it yet.
 239
 240                 return [
 241                         'width' => $arr['width'],
 242                         'height' => $arr['height'],
 243                         'version' => "{$arr['major']}.{$arr['minor']}",
 244                         'resolution' => $arr['resolution'],
 245                         'gamma' => $arr['gamma'] / 10.0 ];
 246         }
 247
 248         /**
 249          * Return an XML string describing the DjVu image
 250          * @return string|bool
 251          */
 252         function retrieveMetaData() {
 253                 global $wgDjvuToXML, $wgDjvuDump, $wgDjvuTxt;
 254
 255                 if ( !$this->isValid() ) {
 256                         return false;
 257                 }
 258
 259                 if ( isset( $wgDjvuDump ) ) {
 260                         # djvudump is faster as of version 3.5
 261                         # https://sourceforge.net/p/djvu/bugs/71/
 262                         $cmd = Shell::escape( $wgDjvuDump ) . ' ' . Shell::escape( $this->mFilename );
 263                         $dump = wfShellExec( $cmd );
 264                         $xml = $this->convertDumpToXML( $dump );
 265                 } elseif ( isset( $wgDjvuToXML ) ) {
 266                         $cmd = Shell::escape( $wgDjvuToXML ) . ' --without-anno --without-text ' .
 267                                 Shell::escape( $this->mFilename );
 268                         $xml = wfShellExec( $cmd );
 269                 } else {
 270                         $xml = null;
 271                 }
 272                 # Text layer
 273                 if ( isset( $wgDjvuTxt ) ) {
 274                         $cmd = Shell::escape( $wgDjvuTxt ) . ' --detail=page ' . Shell::escape( $this->mFilename );
 275                         wfDebug( __METHOD__ . ": $cmd\n" );
 276                         $retval = '';
 277                         $txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
 278                         if ( $retval == 0 ) {
 279                                 # Strip some control characters
 280                                 $txt = preg_replace( "/[\013\035\037]/", "", $txt );
 281                                 $reg = <<<EOR
 282                                         /\(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
 283                                         ((?>    # Text to match is composed of atoms of either:
 284                                                 \\\\. # - any escaped character
 285                                                 |     # - any character different from " and \
 286                                                 [^"\\\\]+
 287                                         )*?)
 288                                         "\s*\)
 289                                         | # Or page can be empty ; in this case, djvutxt dumps ()
 290                                         \(\s*()\)/sx
 291 EOR;
 292                                 $txt = preg_replace_callback( $reg, [ $this, 'pageTextCallback' ], $txt );
 293                                 $txt = "<DjVuTxt>\n<HEAD></HEAD>\n<BODY>\n" . $txt . "</BODY>\n</DjVuTxt>\n";
 294                                 $xml = preg_replace( "/<DjVuXML>/", "<mw-djvu><DjVuXML>", $xml, 1 ) .
 295                                         $txt .
 296                                         '</mw-djvu>';
 297                         }
 298                 }
 299
 300                 return $xml;
 301         }
 302
 303         function pageTextCallback( $matches ) {
 304                 # Get rid of invalid UTF-8, strip control characters
 305                 $val = htmlspecialchars( UtfNormal\Validator::cleanUp( stripcslashes( $matches[1] ) ) );
 306                 $val = str_replace( [ "\n", '�' ], [ '&#10;', '' ], $val );
 307                 return '<PAGE value="' . $val . '" />';
 308         }
 309
 310         /**
 311          * Hack to temporarily work around djvutoxml bug
 312          * @param string $dump
 313          * @return string
 314          */
 315         function convertDumpToXML( $dump ) {
 316                 if ( strval( $dump ) == '' ) {
 317                         return false;
 318                 }
 319
 320                 $xml = <<<EOT
 321 <?xml version="1.0" ?>
 322 <!DOCTYPE DjVuXML PUBLIC "-//W3C//DTD DjVuXML 1.1//EN" "pubtext/DjVuXML-s.dtd">
 323 <DjVuXML>
 324 <HEAD></HEAD>
 325 <BODY>
 326 EOT;
 327
 328                 $dump = str_replace( "\r", '', $dump );
 329                 $line = strtok( $dump, "\n" );
 330                 $m = false;
 331                 $good = false;
 332                 if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
 333                         # Single-page
 334                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 335                                 $good = true;
 336                         } else {
 337                                 return false;
 338                         }
 339                 } elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
 340                         # Multi-page
 341                         $parentLevel = strlen( $m[1] );
 342                         # Find DIRM
 343                         $line = strtok( "\n" );
 344                         while ( $line !== false ) {
 345                                 $childLevel = strspn( $line, ' ' );
 346                                 if ( $childLevel <= $parentLevel ) {
 347                                         # End of chunk
 348                                         break;
 349                                 }
 350
 351                                 if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
 352                                         wfDebug( "Indirect multi-page DjVu document, bad for server!\n" );
 353
 354                                         return false;
 355                                 }
 356                                 if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
 357                                         # Found page
 358                                         if ( $this->parseFormDjvu( $line, $xml ) ) {
 359                                                 $good = true;
 360                                         } else {
 361                                                 return false;
 362                                         }
 363                                 }
 364                                 $line = strtok( "\n" );
 365                         }
 366                 }
 367                 if ( !$good ) {
 368                         return false;
 369                 }
 370
 371                 $xml .= "</BODY>\n</DjVuXML>\n";
 372
 373                 return $xml;
 374         }
 375
 376         function parseFormDjvu( $line, &$xml ) {
 377                 $parentLevel = strspn( $line, ' ' );
 378                 $line = strtok( "\n" );
 379
 380                 # Find INFO
 381                 while ( $line !== false ) {
 382                         $childLevel = strspn( $line, ' ' );
 383                         if ( $childLevel <= $parentLevel ) {
 384                                 # End of chunk
 385                                 break;
 386                         }
 387
 388                         if ( preg_match(
 389                                 '/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
 390                                 $line,
 391                                 $m
 392                         ) ) {
 393                                 $xml .= Xml::tags(
 394                                         'OBJECT',
 395                                         [
 396                                                 # 'data' => '',
 397                                                 # 'type' => 'image/x.djvu',
 398                                                 'height' => $m[2],
 399                                                 'width' => $m[1],
 400                                                 # 'usemap' => '',
 401                                         ],
 402                                         "\n" .
 403                                                 Xml::element( 'PARAM', [ 'name' => 'DPI', 'value' => $m[3] ] ) . "\n" .
 404                                                 Xml::element( 'PARAM', [ 'name' => 'GAMMA', 'value' => $m[4] ] ) . "\n"
 405                                 ) . "\n";
 406
 407                                 return true;
 408                         }
 409                         $line = strtok( "\n" );
 410                 }
 411
 412                 # Not found
 413                 return false;
 414         }
 415 }