includes/Math.php

   1 <?php
   2 /**
   3  * Contain everything related to <math> </math> parsing
   4  * @file
   5  * @ingroup Parser
   6  */
   7
   8 /**
   9  * Takes LaTeX fragments, sends them to a helper program (texvc) for rendering
  10  * to rasterized PNG and HTML and MathML approximations. An appropriate
  11  * rendering form is picked and returned.
  12  *
  13  * @author Tomasz Wegrzanowski, with additions by Brion Vibber (2003, 2004)
  14  * @ingroup Parser
  15  */
  16 class MathRenderer {
  17         var $mode = MW_MATH_MODERN;
  18         var $tex = '';
  19         var $inputhash = '';
  20         var $hash = '';
  21         var $html = '';
  22         var $mathml = '';
  23         var $conservativeness = 0;
  24
  25         function __construct( $tex, $params=array() ) {
  26                 $this->tex = $tex;
  27                 $this->params = $params;
  28         }
  29
  30         function setOutputMode( $mode ) {
  31                 $this->mode = $mode;
  32         }
  33
  34         function render() {
  35                 global $wgTmpDirectory, $wgInputEncoding;
  36                 global $wgTexvc, $wgMathCheckFiles, $wgTexvcBackgroundColor;
  37
  38                 if( $this->mode == MW_MATH_SOURCE ) {
  39                         # No need to render or parse anything more!
  40                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  41                 }
  42                 if( $this->tex == '' ) {
  43                         return; # bug 8372
  44                 }
  45
  46                 if( !$this->_recall() ) {
  47                         if( $wgMathCheckFiles ) {
  48                                 # Ensure that the temp and output directories are available before continuing...
  49                                 if( !file_exists( $wgTmpDirectory ) ) {
  50                                         if( !wfMkdirParents( $wgTmpDirectory ) ) {
  51                                                 return $this->_error( 'math_bad_tmpdir' );
  52                                         }
  53                                 } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  54                                         return $this->_error( 'math_bad_tmpdir' );
  55                                 }
  56                         }
  57
  58                         if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  59                                 return $this->_error( 'math_notexvc' );
  60                         }
  61                         $cmd = $wgTexvc . ' ' .
  62                                         escapeshellarg( $wgTmpDirectory ).' '.
  63                                         escapeshellarg( $wgTmpDirectory ).' '.
  64                                         escapeshellarg( $this->tex ).' '.
  65                                         escapeshellarg( $wgInputEncoding ).' '.
  66                                         escapeshellarg( $wgTexvcBackgroundColor );
  67
  68                         if ( wfIsWindows() ) {
  69                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  70                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  71                         }
  72
  73                         wfDebug( "TeX: $cmd\n" );
  74                         $contents = `$cmd`;
  75                         wfDebug( "TeX output:\n $contents\n---\n" );
  76
  77                         if (strlen($contents) == 0) {
  78                                 return $this->_error( 'math_unknown_error' );
  79                         }
  80
  81                         $retval = substr ($contents, 0, 1);
  82                         $errmsg = '';
  83                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  84                                 if ($retval == 'C') {
  85                                         $this->conservativeness = 2;
  86                                 } else if ($retval == 'M') {
  87                                         $this->conservativeness = 1;
  88                                 } else {
  89                                         $this->conservativeness = 0;
  90                                 }
  91                                 $outdata = substr ($contents, 33);
  92
  93                                 $i = strpos($outdata, "\000");
  94
  95                                 $this->html = substr($outdata, 0, $i);
  96                                 $this->mathml = substr($outdata, $i+1);
  97                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  98                                 $this->html = substr ($contents, 33);
  99                                 if ($retval == 'c') {
 100                                         $this->conservativeness = 2;
 101                                 } else if ($retval == 'm') {
 102                                         $this->conservativeness = 1;
 103                                 } else {
 104                                         $this->conservativeness = 0;
 105                                 }
 106                                 $this->mathml = null;
 107                         } else if ($retval == 'X') {
 108                                 $this->html = null;
 109                                 $this->mathml = substr ($contents, 33);
 110                                 $this->conservativeness = 0;
 111                         } else if ($retval == '+') {
 112                                 $this->html = null;
 113                                 $this->mathml = null;
 114                                 $this->conservativeness = 0;
 115                         } else {
 116                                 $errbit = htmlspecialchars( substr($contents, 1) );
 117                                 switch( $retval ) {
 118                                         case 'E':
 119                                                 $errmsg = $this->_error( 'math_lexing_error', $errbit );
 120                                                 break;
 121                                         case 'S':
 122                                                 $errmsg = $this->_error( 'math_syntax_error', $errbit );
 123                                                 break;
 124                                         case 'F':
 125                                                 $errmsg = $this->_error( 'math_unknown_function', $errbit );
 126                                                 break;
 127                                         default:
 128                                                 $errmsg = $this->_error( 'math_unknown_error', $errbit );
 129                                 }
 130                         }
 131
 132                         if ( !$errmsg ) {
 133                                  $this->hash = substr ($contents, 1, 32);
 134                         }
 135
 136                         wfRunHooks( 'MathAfterTexvc', array( &$this, &$errmsg ) );
 137
 138                         if ( $errmsg ) {
 139                                  return $errmsg;
 140                         }
 141
 142                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 143                                 return $this->_error( 'math_unknown_error' );
 144                         }
 145
 146                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 147                                 return $this->_error( 'math_image_error' );
 148                         }
 149
 150                         if( filesize( "$wgTmpDirectory/{$this->hash}.png" ) == 0 ) {
 151                                 return $this->_error( 'math_image_error' );
 152                         }
 153
 154                         $hashpath = $this->_getHashPath();
 155                         if( !file_exists( $hashpath ) ) {
 156                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 157                                         return $this->_error( 'math_bad_output' );
 158                                 }
 159                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 160                                 return $this->_error( 'math_bad_output' );
 161                         }
 162
 163                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 164                                 return $this->_error( 'math_output_error' );
 165                         }
 166
 167                         # Now save it back to the DB:
 168                         if ( !wfReadOnly() ) {
 169                                 $outmd5_sql = pack('H32', $this->hash);
 170
 171                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 172
 173                                 $dbw = wfGetDB( DB_MASTER );
 174                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 175                                   array(
 176                                         'math_inputhash' => $dbw->encodeBlob($md5_sql),
 177                                         'math_outputhash' => $dbw->encodeBlob($outmd5_sql),
 178                                         'math_html_conservativeness' => $this->conservativeness,
 179                                         'math_html' => $this->html,
 180                                         'math_mathml' => $this->mathml,
 181                                   ), __METHOD__
 182                                 );
 183                         }
 184
 185                         // If we're replacing an older version of the image, make sure it's current.
 186                         global $wgUseSquid;
 187                         if ( $wgUseSquid ) {
 188                                 $urls = array( $this->_mathImageUrl() );
 189                                 $u = new SquidUpdate( $urls );
 190                                 $u->doUpdate();
 191                         }
 192                 }
 193
 194                 return $this->_doRender();
 195         }
 196
 197         function _error( $msg, $append = '' ) {
 198                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 199                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 200                 $source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
 201                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 202         }
 203
 204         function _recall() {
 205                 global $wgMathDirectory, $wgMathCheckFiles;
 206
 207                 $this->md5 = md5( $this->tex );
 208                 $dbr = wfGetDB( DB_SLAVE );
 209                 $rpage = $dbr->selectRow( 'math',
 210                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 211                         array( 'math_inputhash' => $dbr->encodeBlob(pack("H32", $this->md5))), # Binary packed, not hex
 212                         __METHOD__
 213                 );
 214
 215                 if( $rpage !== false ) {
 216                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 217                         $xhash = unpack( 'H32md5', $dbr->decodeBlob($rpage->math_outputhash) . "                " );
 218                         $this->hash = $xhash ['md5'];
 219
 220                         $this->conservativeness = $rpage->math_html_conservativeness;
 221                         $this->html = $rpage->math_html;
 222                         $this->mathml = $rpage->math_mathml;
 223
 224                         $filename = $this->_getHashPath() . "/{$this->hash}.png";
 225
 226                         if( !$wgMathCheckFiles ) {
 227                                 // Short-circuit the file existence & migration checks
 228                                 return true;
 229                         }
 230
 231                         if( file_exists( $filename ) ) {
 232                                 if( filesize( $filename ) == 0 ) {
 233                                         // Some horrible error corrupted stuff :(
 234                                         @unlink( $filename );
 235                                 } else {
 236                                         return true;
 237                                 }
 238                         }
 239
 240                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 241                                 $hashpath = $this->_getHashPath();
 242
 243                                 if( !file_exists( $hashpath ) ) {
 244                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 245                                                 return false;
 246                                         }
 247                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 248                                         return false;
 249                                 }
 250                                 if ( function_exists( "link" ) ) {
 251                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 252                                                         $hashpath . "/{$this->hash}.png" );
 253                                 } else {
 254                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 255                                                         $hashpath . "/{$this->hash}.png" );
 256                                 }
 257                         }
 258
 259                 }
 260
 261                 # Missing from the database and/or the render cache
 262                 return false;
 263         }
 264
 265         /**
 266          * Select among PNG, HTML, or MathML output depending on
 267          */
 268         function _doRender() {
 269                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 270                         return Xml::tags( 'math',
 271                                 $this->_attribs( 'math',
 272                                         array( 'xmlns' => 'http://www.w3.org/1998/Math/MathML' ) ),
 273                                 $this->mathml );
 274                 }
 275                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 276                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 277                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 278                         return $this->_linkToMathImage();
 279                 } else {
 280                         return Xml::tags( 'span',
 281                                 $this->_attribs( 'span',
 282                                         array( 'class' => 'texhtml' ) ),
 283                                 $this->html );
 284                 }
 285         }
 286
 287         function _attribs( $tag, $defaults=array(), $overrides=array() ) {
 288                 $attribs = Sanitizer::validateTagAttributes( $this->params, $tag );
 289                 $attribs = Sanitizer::mergeAttributes( $defaults, $attribs );
 290                 $attribs = Sanitizer::mergeAttributes( $attribs, $overrides );
 291                 return $attribs;
 292         }
 293
 294         function _linkToMathImage() {
 295                 $url = $this->_mathImageUrl();
 296
 297                 return Xml::element( 'img',
 298                         $this->_attribs(
 299                                 'img',
 300                                 array(
 301                                         'class' => 'tex',
 302                                         'alt' => $this->tex ),
 303                                 array(
 304                                         'src' => $url ) ) );
 305         }
 306
 307         function _mathImageUrl() {
 308                 global $wgMathPath;
 309                 $dir = $this->_getHashSubPath();
 310                 return "$wgMathPath/$dir/{$this->hash}.png";
 311         }
 312
 313         function _getHashPath() {
 314                 global $wgMathDirectory;
 315                 $path = $wgMathDirectory .'/' . $this->_getHashSubPath();
 316                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 317                 return $path;
 318         }
 319
 320         function _getHashSubPath() {
 321                 return substr($this->hash, 0, 1)
 322                                         .'/'. substr($this->hash, 1, 1)
 323                                         .'/'. substr($this->hash, 2, 1);
 324         }
 325
 326         public static function renderMath( $tex, $params=array() ) {
 327                 global $wgUser;
 328                 $math = new MathRenderer( $tex, $params );
 329                 $math->setOutputMode( $wgUser->getOption('math'));
 330                 return $math->render();
 331         }
 332 }