includes/Math.php

   1 <?php
   2 /**
   3  * Contain everything related to <math> </math> parsing
   4  * @package MediaWiki
   5  */
   6
   7 /**
   8  * Takes LaTeX fragments, sends them to a helper program (texvc) for rendering
   9  * to rasterized PNG and HTML and MathML approximations. An appropriate
  10  * rendering form is picked and returned.
  11  *
  12  * by Tomasz Wegrzanowski, with additions by Brion Vibber (2003, 2004)
  13  *
  14  * @package MediaWiki
  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 MathRenderer( $tex ) {
  26                 $this->tex = $tex;
  27         }
  28
  29         function setOutputMode( $mode ) {
  30                 $this->mode = $mode;
  31         }
  32
  33         function render() {
  34                 global $wgMathDirectory, $wgTmpDirectory, $wgInputEncoding;
  35                 global $wgTexvc;
  36
  37                 if( $this->mode == MW_MATH_SOURCE ) {
  38                         # No need to render or parse anything more!
  39                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  40                 }
  41
  42                 if( !$this->_recall() ) {
  43                         # Ensure that the temp and output directories are available before continuing...
  44                         if( !file_exists( $wgMathDirectory ) ) {
  45                                 if( !@mkdir( $wgMathDirectory ) ) {
  46                                         return $this->_error( 'math_bad_output' );
  47                                 }
  48                         } elseif( !is_dir( $wgMathDirectory ) || !is_writable( $wgMathDirectory ) ) {
  49                                 return $this->_error( 'math_bad_output' );
  50                         }
  51                         if( !file_exists( $wgTmpDirectory ) ) {
  52                                 if( !@mkdir( $wgTmpDirectory ) ) {
  53                                         return $this->_error( 'math_bad_tmpdir' );
  54                                 }
  55                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  56                                 return $this->_error( 'math_bad_tmpdir' );
  57                         }
  58
  59                         if( !is_executable( $wgTexvc ) ) {
  60                                 return $this->_error( 'math_notexvc' );
  61                         }
  62                         $cmd = $wgTexvc.' '.
  63                                 wfEscapeShellArg($wgTmpDirectory).' '.
  64                                 wfEscapeShellArg($wgMathDirectory).' '.
  65                                 wfEscapeShellArg($this->tex).' '.
  66                                 wfEscapeShellArg($wgInputEncoding);
  67                         wfDebug( 'TeX: '.$cmd );
  68                         $contents = `$cmd`;
  69
  70                         if (strlen($contents) == 0) {
  71                                 return $this->_error( 'math_unknown_error' );
  72                         }
  73
  74                         $retval = substr ($contents, 0, 1);
  75                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  76                                 if ($retval == 'C')
  77                                         $this->conservativeness = 2;
  78                                 else if ($retval == 'M')
  79                                         $this->conservativeness = 1;
  80                                 else
  81                                         $this->conservativeness = 0;
  82                                 $outdata = substr ($contents, 33);
  83
  84                                 $i = strpos($outdata, "\000");
  85
  86                                 $this->html = substr($outdata, 0, $i);
  87                                 $this->mathml = substr($outdata, $i+1);
  88                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  89                                 $this->html = substr ($contents, 33);
  90                                 if ($retval == 'c')
  91                                         $this->conservativeness = 2;
  92                                 else if ($retval == 'm')
  93                                         $this->conservativeness = 1;
  94                                 else
  95                                         $this->conservativeness = 0;
  96                                 $this->mathml = NULL;
  97                         } else if ($retval == 'X') {
  98                                 $outhtml = NULL;
  99                                 $this->mathml = substr ($contents, 33);
 100                                 $this->conservativeness = 0;
 101                         } else if ($retval == '+') {
 102                                 $this->outhtml = NULL;
 103                                 $this->mathml = NULL;
 104                                 $this->conservativeness = 0;
 105                         } else {
 106                                 $errbit = htmlspecialchars( substr($contents, 1) );
 107                                 switch( $retval ) {
 108                                         case 'E': return $this->_error( 'math_lexing_error', $errbit );
 109                                         case 'S': return $this->_error( 'math_syntax_error', $errbit );
 110                                         case 'F': return $this->_error( 'math_unknown_function', $errbit );
 111                                         default:  return $this->_error( 'math_unknown_error', $errbit );
 112                                 }
 113                         }
 114
 115                         $this->hash = substr ($contents, 1, 32);
 116                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 117                                 return $this->_error( 'math_unknown_error' );
 118                         }
 119
 120                         if( !file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 121                                 return $this->_error( 'math_image_error' );
 122                         }
 123
 124                         # Now save it back to the DB:
 125                         $outmd5_sql = pack('H32', $this->hash);
 126
 127                         $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 128
 129                         $dbw =& wfGetDB( DB_MASTER );
 130                         $dbw->replace( 'math', array( 'math_inputhash' ),
 131                           array(
 132                                 'math_inputhash' => $md5_sql,
 133                                 'math_outputhash' => $outmd5_sql,
 134                                 'math_html_conservativeness' => $this->conservativeness,
 135                                 'math_html' => $outhtml,
 136                                 'math_mathml' => $mathml,
 137                           ), $fname, array( 'IGNORE' )
 138                         );
 139
 140                 }
 141
 142                 return $this->_doRender();
 143         }
 144
 145         function _error( $msg, $append = '' ) {
 146                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 147                 $munk = htmlspecialchars( wfMsg( 'math_unknown_error' ) );
 148                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 149                 $source = htmlspecialchars($this->tex);
 150                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 151         }
 152
 153         function _recall() {
 154                 global $wgMathDirectory;
 155                 $fname = 'MathRenderer::_recall';
 156
 157                 $this->md5 = md5( $this->tex );
 158                 $dbr =& wfGetDB( DB_SLAVE );
 159                 $rpage = $dbr->selectRow( 'math',
 160                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 161                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 162                         $fname
 163                 );
 164
 165                 if( $rpage !== false ) {
 166                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 167                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 168                         $this->hash = $xhash ['md5'];
 169
 170                         $this->conservativeness = $rpage->math_html_conservativeness;
 171                         $this->html = $rpage->math_html;
 172                         $this->mathml = $rpage->math_mathml;
 173
 174                         if( file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 175                                 return true;
 176                         }
 177                 }
 178
 179                 # Missing from the database and/or the render cache
 180                 return false;
 181         }
 182
 183         /**
 184          * Select among PNG, HTML, or MathML output depending on
 185          */
 186         function _doRender() {
 187                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 188                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 189                 }
 190                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 191                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 192                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 193                         return $this->_linkToMathImage();
 194                 } else {
 195                         return '<span class="texhtml">'.$this->html.'</span>';
 196                 }
 197         }
 198
 199         function _linkToMathImage() {
 200                 global $wgMathPath;
 201                 $url = htmlspecialchars( "$wgMathPath/{$this->hash}.png" );
 202                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 203                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 204         }
 205
 206 }
 207
 208 function renderMath( $tex ) {
 209         global $wgUser;
 210         $math = new MathRenderer( $tex );
 211         $math->setOutputMode( $wgUser->getOption('math'));
 212         return $math->render();
 213 }
 214
 215 ?>