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                         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( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  54                                 return $this->_error( 'math_notexvc' );
  55                         }
  56                         $cmd = $wgTexvc . ' ' .
  57                                         escapeshellarg( $wgTmpDirectory ).' '.
  58                                         escapeshellarg( $wgTmpDirectory ).' '.
  59                                         escapeshellarg( $this->tex ).' '.
  60                                         escapeshellarg( $wgInputEncoding );
  61
  62                         if ( wfIsWindows() ) {
  63                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  64                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  65                         }
  66
  67                         wfDebug( "TeX: $cmd\n" );
  68                         $contents = `$cmd`;
  69                         wfDebug( "TeX output:\n $contents\n---\n" );
  70
  71                         if (strlen($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 $this->_error( 'math_unknown_error' );
 119                         }
 120
 121                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 122                                 return $this->_error( 'math_image_error' );
 123                         }
 124
 125                         $hashpath = $this->_getHashPath();
 126                         if( !file_exists( $hashpath ) ) {
 127                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 128                                         return $this->_error( 'math_bad_output' );
 129                                 }
 130                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 131                                 return $this->_error( 'math_bad_output' );
 132                         }
 133
 134                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 135                                 return $this->_error( 'math_output_error' );
 136                         }
 137
 138                         # Now save it back to the DB:
 139                         if ( !wfReadOnly() ) {
 140                                 $outmd5_sql = pack('H32', $this->hash);
 141
 142                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 143
 144                                 $dbw =& wfGetDB( DB_MASTER );
 145                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 146                                   array(
 147                                         'math_inputhash' => $md5_sql,
 148                                         'math_outputhash' => $outmd5_sql,
 149                                         'math_html_conservativeness' => $this->conservativeness,
 150                                         'math_html' => $this->html,
 151                                         'math_mathml' => $this->mathml,
 152                                   ), $fname, array( 'IGNORE' )
 153                                 );
 154                         }
 155
 156                 }
 157
 158                 return $this->_doRender();
 159         }
 160
 161         function _error( $msg, $append = '' ) {
 162                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 163                 $munk = htmlspecialchars( wfMsg( 'math_unknown_error' ) );
 164                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 165                 $source = htmlspecialchars($this->tex);
 166                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 167         }
 168
 169         function _recall() {
 170                 global $wgMathDirectory;
 171                 $fname = 'MathRenderer::_recall';
 172
 173                 $this->md5 = md5( $this->tex );
 174                 $dbr =& wfGetDB( DB_SLAVE );
 175                 $rpage = $dbr->selectRow( 'math',
 176                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 177                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 178                         $fname
 179                 );
 180
 181                 if( $rpage !== false ) {
 182                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 183                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 184                         $this->hash = $xhash ['md5'];
 185
 186                         $this->conservativeness = $rpage->math_html_conservativeness;
 187                         $this->html = $rpage->math_html;
 188                         $this->mathml = $rpage->math_mathml;
 189
 190                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 191                                 return true;
 192                         }
 193
 194                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 195                                 $hashpath = $this->_getHashPath();
 196
 197                                 if( !file_exists( $hashpath ) ) {
 198                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 199                                                 return false;
 200                                         }
 201                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 202                                         return false;
 203                                 }
 204                                 if ( function_exists( "link" ) ) {
 205                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 206                                                         $hashpath . "/{$this->hash}.png" );
 207                                 } else {
 208                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 209                                                         $hashpath . "/{$this->hash}.png" );
 210                                 }
 211                         }
 212
 213                 }
 214
 215                 # Missing from the database and/or the render cache
 216                 return false;
 217         }
 218
 219         /**
 220          * Select among PNG, HTML, or MathML output depending on
 221          */
 222         function _doRender() {
 223                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 224                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 225                 }
 226                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 227                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 228                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 229                         return $this->_linkToMathImage();
 230                 } else {
 231                         return '<span class="texhtml">'.$this->html.'</span>';
 232                 }
 233         }
 234
 235         function _linkToMathImage() {
 236                 global $wgMathPath;
 237                 $url = htmlspecialchars( "$wgMathPath/" . substr($this->hash, 0, 1)
 238                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 239                                         . "/{$this->hash}.png" );
 240                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 241                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 242         }
 243
 244         function _getHashPath() {
 245                 global $wgMathDirectory;
 246                 $path = $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 247                                         .'/'. substr($this->hash, 1, 1)
 248                                         .'/'. substr($this->hash, 2, 1);
 249                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 250                 return $path;
 251         }
 252
 253
 254 }
 255
 256 function renderMath( $tex ) {
 257         global $wgUser;
 258         $math = new MathRenderer( $tex );
 259         $math->setOutputMode( $wgUser->getOption('math'));
 260         return $math->render();
 261 }
 262
 263 ?>