includes/Math.php

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