includes/Math.php

   1 <?php
   2 /**
   3  * Contain everything related to <math> </math> parsing
   4  */
   5
   6 /**
   7  * Takes LaTeX fragments, sends them to a helper program (texvc) for rendering
   8  * to rasterized PNG and HTML and MathML approximations. An appropriate
   9  * rendering form is picked and returned.
  10  *
  11  * by Tomasz Wegrzanowski, with additions by Brion Vibber (2003, 2004)
  12  */
  13 class MathRenderer {
  14         var $mode = MW_MATH_MODERN;
  15         var $tex = '';
  16         var $inputhash = '';
  17         var $hash = '';
  18         var $html = '';
  19         var $mathml = '';
  20         var $conservativeness = 0;
  21
  22         function MathRenderer( $tex ) {
  23                 $this->tex = $tex;
  24         }
  25
  26         function setOutputMode( $mode ) {
  27                 $this->mode = $mode;
  28         }
  29
  30         function render() {
  31                 global $wgMathDirectory, $wgTmpDirectory, $wgInputEncoding;
  32                 global $wgTexvc;
  33
  34                 if( $this->mode == MW_MATH_SOURCE ) {
  35                         # No need to render or parse anything more!
  36                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  37                 }
  38
  39                 if( !$this->_recall() ) {
  40                         # Ensure that the temp and output directories are available before continuing...
  41                         if( !file_exists( $wgMathDirectory ) ) {
  42                                 if( !@mkdir( $wgMathDirectory ) ) {
  43                                         return $this->_error( 'math_bad_output' );
  44                                 }
  45                         } elseif( !is_dir( $wgMathDirectory ) || !is_writable( $wgMathDirectory ) ) {
  46                                 return $this->_error( 'math_bad_output' );
  47                         }
  48                         if( !file_exists( $wgTmpDirectory ) ) {
  49                                 if( !@mkdir( $wgTmpDirectory ) ) {
  50                                         return $this->_error( 'math_bad_tmpdir' );
  51                                 }
  52                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  53                                 return $this->_error( 'math_bad_tmpdir' );
  54                         }
  55
  56                         if( !is_executable( $wgTexvc ) ) {
  57                                 return $this->_error( 'math_notexvc' );
  58                         }
  59                         $cmd = $wgTexvc.' '.
  60                                 wfEscapeShellArg($wgTmpDirectory).' '.
  61                                 wfEscapeShellArg($wgMathDirectory).' '.
  62                                 wfEscapeShellArg($this->tex).' '.
  63                                 wfEscapeShellArg($wgInputEncoding);
  64                         wfDebug( 'TeX: '.$cmd );
  65                         $contents = `$cmd`;
  66
  67                         if (strlen($contents) == 0) {
  68                                 return $this->_error( 'math_unknown_error' );
  69                         }
  70
  71                         $retval = substr ($contents, 0, 1);
  72                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  73                                 if ($retval == 'C')
  74                                         $this->conservativeness = 2;
  75                                 else if ($retval == 'M')
  76                                         $this->conservativeness = 1;
  77                                 else
  78                                         $this->conservativeness = 0;
  79                                 $outdata = substr ($contents, 33);
  80
  81                                 $i = strpos($outdata, "\000");
  82
  83                                 $this->html = substr($outdata, 0, $i);
  84                                 $this->mathml = substr($outdata, $i+1);
  85                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  86                                 $this->html = substr ($contents, 33);
  87                                 if ($retval == 'c')
  88                                         $this->conservativeness = 2;
  89                                 else if ($retval == 'm')
  90                                         $this->conservativeness = 1;
  91                                 else
  92                                         $this->conservativeness = 0;
  93                                 $this->mathml = NULL;
  94                         } else if ($retval == 'X') {
  95                                 $outhtml = NULL;
  96                                 $this->mathml = substr ($contents, 33);
  97                                 $this->conservativeness = 0;
  98                         } else if ($retval == '+') {
  99                                 $this->outhtml = NULL;
 100                                 $this->mathml = NULL;
 101                                 $this->conservativeness = 0;
 102                         } else {
 103                                 $errbit = htmlspecialchars( substr($contents, 1) );
 104                                 switch( $retval ) {
 105                                         case 'E': return $this->_error( 'math_lexing_error', $errbit );
 106                                         case 'S': return $this->_error( 'math_syntax_error', $errbit );
 107                                         case 'F': return $this->_error( 'math_unknown_function', $errbit );
 108                                         default:  return $this->_error( 'math_unknown_error', $errbit );
 109                                 }
 110                         }
 111
 112                         $this->hash = substr ($contents, 1, 32);
 113                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 114                                 return $this->_error( 'math_unknown_error' );
 115                         }
 116
 117                         if( !file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 118                                 return $this->_error( 'math_image_error' );
 119                         }
 120
 121                         # Now save it back to the DB:
 122                         $outmd5_sql = pack('H32', $this->hash);
 123
 124                         $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 125
 126                         $dbw =& wfGetDB( DB_MASTER );
 127                         $dbw->replace( 'math', array( 'math_inputhash' ),
 128                           array(
 129                                 'math_inputhash' => $md5_sql,
 130                                 'math_outputhash' => $outmd5_sql,
 131                                 'math_html_conservativeness' => $this->conservativeness,
 132                                 'math_html' => $outhtml,
 133                                 'math_mathml' => $mathml,
 134                           ), $fname, array( 'IGNORE' )
 135                         );
 136
 137                 }
 138
 139                 return $this->_doRender();
 140         }
 141
 142         function _error( $msg, $append = '' ) {
 143                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 144                 $munk = htmlspecialchars( wfMsg( 'math_unknown_error' ) );
 145                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 146                 $source = htmlspecialchars($this->tex);
 147                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 148         }
 149
 150         function _recall() {
 151                 global $wgMathDirectory;
 152                 $fname = 'MathRenderer::_recall';
 153
 154                 $this->md5 = md5( $this->tex );
 155                 $dbr =& wfGetDB( DB_SLAVE );
 156                 $rpage = $dbr->getArray( 'math',
 157                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 158                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 159                         $fname
 160                 );
 161
 162                 if( $rpage !== false ) {
 163                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 164                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 165                         $this->hash = $xhash ['md5'];
 166
 167                         $this->conservativeness = $rpage->math_html_conservativeness;
 168                         $this->html = $rpage->math_html;
 169                         $this->mathml = $rpage->math_mathml;
 170
 171                         if( file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 172                                 return true;
 173                         }
 174                 }
 175
 176                 # Missing from the database and/or the render cache
 177                 return false;
 178         }
 179
 180         /**
 181          * Select among PNG, HTML, or MathML output depending on
 182          */
 183         function _doRender() {
 184                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 185                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 186                 }
 187                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 188                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 189                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 190                         return $this->_linkToMathImage();
 191                 } else {
 192                         return '<span class="texhtml">'.$this->html.'</span>';
 193                 }
 194         }
 195
 196         function _linkToMathImage() {
 197                 global $wgMathPath;
 198                 $url = htmlspecialchars( "$wgMathPath/{$this->hash}.png" );
 199                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 200                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 201         }
 202
 203 }
 204
 205 function renderMath( $tex ) {
 206         global $wgUser;
 207         $math = new MathRenderer( $tex );
 208         $math->setOutputMode( $wgUser->getOption('math'));
 209         return $math->render();
 210 }
 211
 212 ?>