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                 $fname = 'MathRenderer::render';
  37
  38                 if( $this->mode == MW_MATH_SOURCE ) {
  39                         # No need to render or parse anything more!
  40                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  41                 }
  42
  43                 if( !$this->_recall() ) {
  44                         # Ensure that the temp and output directories are available before continuing...
  45                         if( !file_exists( $wgMathDirectory ) ) {
  46                                 if( !@mkdir( $wgMathDirectory ) ) {
  47                                         return $this->_error( 'math_bad_output' );
  48                                 }
  49                         } elseif( !is_dir( $wgMathDirectory ) || !is_writable( $wgMathDirectory ) ) {
  50                                 return $this->_error( 'math_bad_output' );
  51                         }
  52                         if( !file_exists( $wgTmpDirectory ) ) {
  53                                 if( !@mkdir( $wgTmpDirectory ) ) {
  54                                         return $this->_error( 'math_bad_tmpdir' );
  55                                 }
  56                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  57                                 return $this->_error( 'math_bad_tmpdir' );
  58                         }
  59
  60                         if( !is_executable( $wgTexvc ) ) {
  61                                 return $this->_error( 'math_notexvc' );
  62                         }
  63                         $cmd = $wgTexvc.' '.
  64                                 wfEscapeShellArg($wgTmpDirectory).' '.
  65                                 wfEscapeShellArg($wgMathDirectory).' '.
  66                                 wfEscapeShellArg($this->tex).' '.
  67                                 wfEscapeShellArg($wgInputEncoding);
  68                         wfDebug( 'TeX: '.$cmd );
  69                         $contents = `$cmd`;
  70
  71                         if (strlen($contents) == 0) {
  72                                 return $this->_error( 'math_unknown_error' );
  73                         }
  74
  75                         $retval = substr ($contents, 0, 1);
  76                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  77                                 if ($retval == 'C')
  78                                         $this->conservativeness = 2;
  79                                 else if ($retval == 'M')
  80                                         $this->conservativeness = 1;
  81                                 else
  82                                         $this->conservativeness = 0;
  83                                 $outdata = substr ($contents, 33);
  84
  85                                 $i = strpos($outdata, "\000");
  86
  87                                 $this->html = substr($outdata, 0, $i);
  88                                 $this->mathml = substr($outdata, $i+1);
  89                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  90                                 $this->html = substr ($contents, 33);
  91                                 if ($retval == 'c')
  92                                         $this->conservativeness = 2;
  93                                 else if ($retval == 'm')
  94                                         $this->conservativeness = 1;
  95                                 else
  96                                         $this->conservativeness = 0;
  97                                 $this->mathml = NULL;
  98                         } else if ($retval == 'X') {
  99                                 $this->html = NULL;
 100                                 $this->mathml = substr ($contents, 33);
 101                                 $this->conservativeness = 0;
 102                         } else if ($retval == '+') {
 103                                 $this->html = NULL;
 104                                 $this->mathml = NULL;
 105                                 $this->conservativeness = 0;
 106                         } else {
 107                                 $errbit = htmlspecialchars( substr($contents, 1) );
 108                                 switch( $retval ) {
 109                                         case 'E': return $this->_error( 'math_lexing_error', $errbit );
 110                                         case 'S': return $this->_error( 'math_syntax_error', $errbit );
 111                                         case 'F': return $this->_error( 'math_unknown_function', $errbit );
 112                                         default:  return $this->_error( 'math_unknown_error', $errbit );
 113                                 }
 114                         }
 115
 116                         $this->hash = substr ($contents, 1, 32);
 117                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 118                                 return $this->_error( 'math_unknown_error' );
 119                         }
 120
 121                         if( !file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 122                                 return $this->_error( 'math_image_error' );
 123                         }
 124
 125                         # Now save it back to the DB:
 126                         if ( !wfReadOnly() ) {
 127                                 $outmd5_sql = pack('H32', $this->hash);
 128
 129                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 130
 131                                 $dbw =& wfGetDB( DB_MASTER );
 132                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 133                                   array(
 134                                         'math_inputhash' => $md5_sql,
 135                                         'math_outputhash' => $outmd5_sql,
 136                                         'math_html_conservativeness' => $this->conservativeness,
 137                                         'math_html' => $this->html,
 138                                         'math_mathml' => $this->mathml,
 139                                   ), $fname, array( 'IGNORE' )
 140                                 );
 141                         }
 142
 143                 }
 144
 145                 return $this->_doRender();
 146         }
 147
 148         function _error( $msg, $append = '' ) {
 149                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 150                 $munk = htmlspecialchars( wfMsg( 'math_unknown_error' ) );
 151                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 152                 $source = htmlspecialchars($this->tex);
 153                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 154         }
 155
 156         function _recall() {
 157                 global $wgMathDirectory;
 158                 $fname = 'MathRenderer::_recall';
 159
 160                 $this->md5 = md5( $this->tex );
 161                 $dbr =& wfGetDB( DB_SLAVE );
 162                 $rpage = $dbr->selectRow( 'math',
 163                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 164                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 165                         $fname
 166                 );
 167
 168                 if( $rpage !== false ) {
 169                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 170                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 171                         $this->hash = $xhash ['md5'];
 172
 173                         $this->conservativeness = $rpage->math_html_conservativeness;
 174                         $this->html = $rpage->math_html;
 175                         $this->mathml = $rpage->math_mathml;
 176
 177                         if( file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 178                                 return true;
 179                         }
 180                 }
 181
 182                 # Missing from the database and/or the render cache
 183                 return false;
 184         }
 185
 186         /**
 187          * Select among PNG, HTML, or MathML output depending on
 188          */
 189         function _doRender() {
 190                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 191                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 192                 }
 193                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 194                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 195                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 196                         return $this->_linkToMathImage();
 197                 } else {
 198                         return '<span class="texhtml">'.$this->html.'</span>';
 199                 }
 200         }
 201
 202         function _linkToMathImage() {
 203                 global $wgMathPath;
 204                 $url = htmlspecialchars( "$wgMathPath/{$this->hash}.png" );
 205                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 206                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 207         }
 208
 209 }
 210
 211 function renderMath( $tex ) {
 212         global $wgUser;
 213         $math = new MathRenderer( $tex );
 214         $math->setOutputMode( $wgUser->getOption('math'));
 215         return $math->render();
 216 }
 217
 218 ?>