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