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 $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                         $hashpath = $this->_getHashPath();
  46
  47                         if( !file_exists( $hashpath ) ) {
  48                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
  49                                         return $this->_error( 'math_bad_output' );
  50                                 }
  51                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
  52                                 return $this->_error( 'math_bad_output' );
  53                         }
  54                         if( !file_exists( $wgTmpDirectory ) ) {
  55                                 if( !@mkdir( $wgTmpDirectory ) ) {
  56                                         return $this->_error( 'math_bad_tmpdir' );
  57                                 }
  58                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  59                                 return $this->_error( 'math_bad_tmpdir' );
  60                         }
  61
  62                         if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  63                                 return $this->_error( 'math_notexvc' );
  64                         }
  65                         $cmd = $wgTexvc . ' ' .
  66                                         escapeshellarg( $wgTmpDirectory ).' '.
  67                                         escapeshellarg( $hashpath ).' '.
  68                                         escapeshellarg( $this->tex ).' '.
  69                                         escapeshellarg( $wgInputEncoding );
  70
  71                         if ( wfIsWindows() ) {
  72                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  73                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  74                         }
  75
  76                         wfDebug( "TeX: $cmd\n" );
  77                         $contents = `$cmd`;
  78                         wfDebug( "TeX output:\n $contents\n---\n" );
  79
  80                         if (strlen($contents) == 0) {
  81                                 return $this->_error( 'math_unknown_error' );
  82                         }
  83
  84                         $retval = substr ($contents, 0, 1);
  85                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  86                                 if ($retval == 'C')
  87                                         $this->conservativeness = 2;
  88                                 else if ($retval == 'M')
  89                                         $this->conservativeness = 1;
  90                                 else
  91                                         $this->conservativeness = 0;
  92                                 $outdata = substr ($contents, 33);
  93
  94                                 $i = strpos($outdata, "\000");
  95
  96                                 $this->html = substr($outdata, 0, $i);
  97                                 $this->mathml = substr($outdata, $i+1);
  98                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  99                                 $this->html = substr ($contents, 33);
 100                                 if ($retval == 'c')
 101                                         $this->conservativeness = 2;
 102                                 else if ($retval == 'm')
 103                                         $this->conservativeness = 1;
 104                                 else
 105                                         $this->conservativeness = 0;
 106                                 $this->mathml = NULL;
 107                         } else if ($retval == 'X') {
 108                                 $this->html = NULL;
 109                                 $this->mathml = substr ($contents, 33);
 110                                 $this->conservativeness = 0;
 111                         } else if ($retval == '+') {
 112                                 $this->html = NULL;
 113                                 $this->mathml = NULL;
 114                                 $this->conservativeness = 0;
 115                         } else {
 116                                 $errbit = htmlspecialchars( substr($contents, 1) );
 117                                 switch( $retval ) {
 118                                         case 'E': return $this->_error( 'math_lexing_error', $errbit );
 119                                         case 'S': return $this->_error( 'math_syntax_error', $errbit );
 120                                         case 'F': return $this->_error( 'math_unknown_function', $errbit );
 121                                         default:  return $this->_error( 'math_unknown_error', $errbit );
 122                                 }
 123                         }
 124
 125                         $this->hash = substr ($contents, 1, 32);
 126                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 127                                 return $this->_error( 'math_unknown_error' );
 128                         }
 129
 130                         if( !file_exists( "$hashpath/{$this->hash}.png" ) ) {
 131                                 return $this->_error( 'math_image_error' );
 132                         }
 133
 134                         # Now save it back to the DB:
 135                         if ( !wfReadOnly() ) {
 136                                 $outmd5_sql = pack('H32', $this->hash);
 137
 138                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 139
 140                                 $dbw =& wfGetDB( DB_MASTER );
 141                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 142                                   array(
 143                                         'math_inputhash' => $md5_sql,
 144                                         'math_outputhash' => $outmd5_sql,
 145                                         'math_html_conservativeness' => $this->conservativeness,
 146                                         'math_html' => $this->html,
 147                                         'math_mathml' => $this->mathml,
 148                                   ), $fname, array( 'IGNORE' )
 149                                 );
 150                         }
 151
 152                 }
 153
 154                 return $this->_doRender();
 155         }
 156
 157         function _error( $msg, $append = '' ) {
 158                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 159                 $munk = htmlspecialchars( wfMsg( 'math_unknown_error' ) );
 160                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 161                 $source = htmlspecialchars($this->tex);
 162                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 163         }
 164
 165         function _recall() {
 166                 global $wgMathDirectory;
 167                 $fname = 'MathRenderer::_recall';
 168
 169                 $this->md5 = md5( $this->tex );
 170                 $dbr =& wfGetDB( DB_SLAVE );
 171                 $rpage = $dbr->selectRow( 'math',
 172                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 173                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 174                         $fname
 175                 );
 176
 177                 if( $rpage !== false ) {
 178                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 179                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 180                         $this->hash = $xhash ['md5'];
 181
 182                         $this->conservativeness = $rpage->math_html_conservativeness;
 183                         $this->html = $rpage->math_html;
 184                         $this->mathml = $rpage->math_mathml;
 185
 186                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 187                                 return true;
 188                         }
 189
 190                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 191                                 $hashpath = $this->_getHashPath();
 192
 193                                 if( !file_exists( $hashpath ) ) {
 194                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 195                                                 return false;
 196                                         }
 197                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 198                                         return false;
 199                                 }
 200                                 if ( function_exists( "link" ) ) {
 201                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 202                                                         $hashpath . "/{$this->hash}.png" );
 203                                 } else {
 204                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 205                                                         $hashpath . "/{$this->hash}.png" );
 206                                 }
 207                         }
 208
 209                 }
 210
 211                 # Missing from the database and/or the render cache
 212                 return false;
 213         }
 214
 215         /**
 216          * Select among PNG, HTML, or MathML output depending on
 217          */
 218         function _doRender() {
 219                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 220                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 221                 }
 222                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 223                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 224                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 225                         return $this->_linkToMathImage();
 226                 } else {
 227                         return '<span class="texhtml">'.$this->html.'</span>';
 228                 }
 229         }
 230
 231         function _linkToMathImage() {
 232                 global $wgMathPath;
 233                 $url = htmlspecialchars( "$wgMathPath/" . substr($this->hash, 0, 1)
 234                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 235                                         . "/{$this->hash}.png" );
 236                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 237                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 238         }
 239
 240         function _getHashPath() {
 241                 global $wgMathDirectory;
 242                 return $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 243                                         .'/'. substr($this->hash, 1, 1)
 244                                         .'/'. substr($this->hash, 2, 1);
 245         }
 246
 247
 248 }
 249
 250 function renderMath( $tex ) {
 251         global $wgUser;
 252         $math = new MathRenderer( $tex );
 253         $math->setOutputMode( $wgUser->getOption('math'));
 254         return $math->render();
 255 }
 256
 257 ?>