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( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  61                                 return $this->_error( 'math_notexvc' );
  62                         }
  63                         $cmd = $wgTexvc . ' ' .
  64                                         escapeshellarg( $wgTmpDirectory ).' '.
  65                                         escapeshellarg( $wgMathDirectory ).' '.
  66                                         escapeshellarg( $this->tex ).' '.
  67                                         escapeshellarg( $wgInputEncoding );
  68
  69                         if ( wfIsWindows() ) {
  70                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  71                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  72                         }
  73
  74                         wfDebug( "TeX: $cmd\n" );
  75                         $contents = `$cmd`;
  76                         wfDebug( "TeX output:\n $contents\n---\n" );
  77
  78                         if (strlen($contents) == 0) {
  79                                 return $this->_error( 'math_unknown_error' );
  80                         }
  81
  82                         $retval = substr ($contents, 0, 1);
  83                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  84                                 if ($retval == 'C')
  85                                         $this->conservativeness = 2;
  86                                 else if ($retval == 'M')
  87                                         $this->conservativeness = 1;
  88                                 else
  89                                         $this->conservativeness = 0;
  90                                 $outdata = substr ($contents, 33);
  91
  92                                 $i = strpos($outdata, "\000");
  93
  94                                 $this->html = substr($outdata, 0, $i);
  95                                 $this->mathml = substr($outdata, $i+1);
  96                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  97                                 $this->html = substr ($contents, 33);
  98                                 if ($retval == 'c')
  99                                         $this->conservativeness = 2;
 100                                 else if ($retval == 'm')
 101                                         $this->conservativeness = 1;
 102                                 else
 103                                         $this->conservativeness = 0;
 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': return $this->_error( 'math_lexing_error', $errbit );
 117                                         case 'S': return $this->_error( 'math_syntax_error', $errbit );
 118                                         case 'F': return $this->_error( 'math_unknown_function', $errbit );
 119                                         default:  return $this->_error( 'math_unknown_error', $errbit );
 120                                 }
 121                         }
 122
 123                         $this->hash = substr ($contents, 1, 32);
 124                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 125                                 return $this->_error( 'math_unknown_error' );
 126                         }
 127
 128                         if( !file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 129                                 return $this->_error( 'math_image_error' );
 130                         }
 131
 132                         # Now save it back to the DB:
 133                         if ( !wfReadOnly() ) {
 134                                 $outmd5_sql = pack('H32', $this->hash);
 135
 136                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 137
 138                                 $dbw =& wfGetDB( DB_MASTER );
 139                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 140                                   array(
 141                                         'math_inputhash' => $md5_sql,
 142                                         'math_outputhash' => $outmd5_sql,
 143                                         'math_html_conservativeness' => $this->conservativeness,
 144                                         'math_html' => $this->html,
 145                                         'math_mathml' => $this->mathml,
 146                                   ), $fname, array( 'IGNORE' )
 147                                 );
 148                         }
 149
 150                 }
 151
 152                 return $this->_doRender();
 153         }
 154
 155         function _error( $msg, $append = '' ) {
 156                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 157                 $munk = htmlspecialchars( wfMsg( 'math_unknown_error' ) );
 158                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 159                 $source = htmlspecialchars($this->tex);
 160                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 161         }
 162
 163         function _recall() {
 164                 global $wgMathDirectory;
 165                 $fname = 'MathRenderer::_recall';
 166
 167                 $this->md5 = md5( $this->tex );
 168                 $dbr =& wfGetDB( DB_SLAVE );
 169                 $rpage = $dbr->selectRow( 'math',
 170                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 171                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 172                         $fname
 173                 );
 174
 175                 if( $rpage !== false ) {
 176                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 177                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 178                         $this->hash = $xhash ['md5'];
 179
 180                         $this->conservativeness = $rpage->math_html_conservativeness;
 181                         $this->html = $rpage->math_html;
 182                         $this->mathml = $rpage->math_mathml;
 183
 184                         if( file_exists( "$wgMathDirectory/{$this->hash}.png" ) ) {
 185                                 return true;
 186                         }
 187                 }
 188
 189                 # Missing from the database and/or the render cache
 190                 return false;
 191         }
 192
 193         /**
 194          * Select among PNG, HTML, or MathML output depending on
 195          */
 196         function _doRender() {
 197                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 198                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 199                 }
 200                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 201                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 202                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 203                         return $this->_linkToMathImage();
 204                 } else {
 205                         return '<span class="texhtml">'.$this->html.'</span>';
 206                 }
 207         }
 208
 209         function _linkToMathImage() {
 210                 global $wgMathPath;
 211                 $url = htmlspecialchars( "$wgMathPath/{$this->hash}.png" );
 212                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 213                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 214         }
 215
 216 }
 217
 218 function renderMath( $tex ) {
 219         global $wgUser;
 220         $math = new MathRenderer( $tex );
 221         $math->setOutputMode( $wgUser->getOption('math'));
 222         return $math->render();
 223 }
 224
 225 ?>