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                 if( $this->tex == '' ) {
  43                         return; # bug 8372
  44                 }
  45
  46                 if( !$this->_recall() ) {
  47                         # Ensure that the temp and output directories are available before continuing...
  48                         if( !file_exists( $wgTmpDirectory ) ) {
  49                                 if( !@mkdir( $wgTmpDirectory ) ) {
  50                                         return $this->_error( 'math_bad_tmpdir' );
  51                                 }
  52                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  53                                 return $this->_error( 'math_bad_tmpdir' );
  54                         }
  55
  56                         if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  57                                 return $this->_error( 'math_notexvc' );
  58                         }
  59                         $cmd = $wgTexvc . ' ' .
  60                                         escapeshellarg( $wgTmpDirectory ).' '.
  61                                         escapeshellarg( $wgTmpDirectory ).' '.
  62                                         escapeshellarg( $this->tex ).' '.
  63                                         escapeshellarg( $wgInputEncoding );
  64
  65                         if ( wfIsWindows() ) {
  66                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  67                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  68                         }
  69
  70                         wfDebug( "TeX: $cmd\n" );
  71                         $contents = `$cmd`;
  72                         wfDebug( "TeX output:\n $contents\n---\n" );
  73
  74                         if (strlen($contents) == 0) {
  75                                 return $this->_error( 'math_unknown_error' );
  76                         }
  77
  78                         $retval = substr ($contents, 0, 1);
  79                         $errmsg = '';
  80                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  81                                 if ($retval == 'C') {
  82                                         $this->conservativeness = 2;
  83                                 } else if ($retval == 'M') {
  84                                         $this->conservativeness = 1;
  85                                 } else {
  86                                         $this->conservativeness = 0;
  87                                 }
  88                                 $outdata = substr ($contents, 33);
  89
  90                                 $i = strpos($outdata, "\000");
  91
  92                                 $this->html = substr($outdata, 0, $i);
  93                                 $this->mathml = substr($outdata, $i+1);
  94                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  95                                 $this->html = substr ($contents, 33);
  96                                 if ($retval == 'c') {
  97                                         $this->conservativeness = 2;
  98                                 } else if ($retval == 'm') {
  99                                         $this->conservativeness = 1;
 100                                 } else {
 101                                         $this->conservativeness = 0;
 102                                 }
 103                                 $this->mathml = NULL;
 104                         } else if ($retval == 'X') {
 105                                 $this->html = NULL;
 106                                 $this->mathml = substr ($contents, 33);
 107                                 $this->conservativeness = 0;
 108                         } else if ($retval == '+') {
 109                                 $this->html = NULL;
 110                                 $this->mathml = NULL;
 111                                 $this->conservativeness = 0;
 112                         } else {
 113                                 $errbit = htmlspecialchars( substr($contents, 1) );
 114                                 switch( $retval ) {
 115                                         case 'E': $errmsg = $this->_error( 'math_lexing_error', $errbit );
 116                                         case 'S': $errmsg = $this->_error( 'math_syntax_error', $errbit );
 117                                         case 'F': $errmsg = $this->_error( 'math_unknown_function', $errbit );
 118                                         default:  $errmsg = $this->_error( 'math_unknown_error', $errbit );
 119                                 }
 120                         }
 121
 122                         if ( !$errmsg ) {
 123                                  $this->hash = substr ($contents, 1, 32);
 124                         }
 125
 126                         wfRunHooks( 'MathAfterTexvc', array( &$this, &$errmsg ) );
 127
 128                         if ( $errmsg ) {
 129                                  return $errmsg;
 130                         }
 131
 132                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 133                                 return $this->_error( 'math_unknown_error' );
 134                         }
 135
 136                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 137                                 return $this->_error( 'math_image_error' );
 138                         }
 139
 140                         $hashpath = $this->_getHashPath();
 141                         if( !file_exists( $hashpath ) ) {
 142                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 143                                         return $this->_error( 'math_bad_output' );
 144                                 }
 145                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 146                                 return $this->_error( 'math_bad_output' );
 147                         }
 148
 149                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 150                                 return $this->_error( 'math_output_error' );
 151                         }
 152
 153                         # Now save it back to the DB:
 154                         if ( !wfReadOnly() ) {
 155                                 $outmd5_sql = pack('H32', $this->hash);
 156
 157                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 158
 159                                 $dbw =& wfGetDB( DB_MASTER );
 160                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 161                                   array(
 162                                         'math_inputhash' => $md5_sql,
 163                                         'math_outputhash' => $outmd5_sql,
 164                                         'math_html_conservativeness' => $this->conservativeness,
 165                                         'math_html' => $this->html,
 166                                         'math_mathml' => $this->mathml,
 167                                   ), $fname, array( 'IGNORE' )
 168                                 );
 169                         }
 170
 171                 }
 172
 173                 return $this->_doRender();
 174         }
 175
 176         function _error( $msg, $append = '' ) {
 177                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 178                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 179                 $source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
 180                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 181         }
 182
 183         function _recall() {
 184                 global $wgMathDirectory;
 185                 $fname = 'MathRenderer::_recall';
 186
 187                 $this->md5 = md5( $this->tex );
 188                 $dbr =& wfGetDB( DB_SLAVE );
 189                 $rpage = $dbr->selectRow( 'math',
 190                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 191                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 192                         $fname
 193                 );
 194
 195                 if( $rpage !== false ) {
 196                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 197                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 198                         $this->hash = $xhash ['md5'];
 199
 200                         $this->conservativeness = $rpage->math_html_conservativeness;
 201                         $this->html = $rpage->math_html;
 202                         $this->mathml = $rpage->math_mathml;
 203
 204                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 205                                 return true;
 206                         }
 207
 208                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 209                                 $hashpath = $this->_getHashPath();
 210
 211                                 if( !file_exists( $hashpath ) ) {
 212                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 213                                                 return false;
 214                                         }
 215                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 216                                         return false;
 217                                 }
 218                                 if ( function_exists( "link" ) ) {
 219                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 220                                                         $hashpath . "/{$this->hash}.png" );
 221                                 } else {
 222                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 223                                                         $hashpath . "/{$this->hash}.png" );
 224                                 }
 225                         }
 226
 227                 }
 228
 229                 # Missing from the database and/or the render cache
 230                 return false;
 231         }
 232
 233         /**
 234          * Select among PNG, HTML, or MathML output depending on
 235          */
 236         function _doRender() {
 237                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 238                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 239                 }
 240                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 241                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 242                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 243                         return $this->_linkToMathImage();
 244                 } else {
 245                         return '<span class="texhtml">'.$this->html.'</span>';
 246                 }
 247         }
 248
 249         function _linkToMathImage() {
 250                 global $wgMathPath;
 251                 $url = htmlspecialchars( "$wgMathPath/" . substr($this->hash, 0, 1)
 252                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 253                                         . "/{$this->hash}.png" );
 254                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 255                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 256         }
 257
 258         function _getHashPath() {
 259                 global $wgMathDirectory;
 260                 $path = $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 261                                         .'/'. substr($this->hash, 1, 1)
 262                                         .'/'. substr($this->hash, 2, 1);
 263                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 264                 return $path;
 265         }
 266
 267         public static function renderMath( $tex ) {
 268                 global $wgUser;
 269                 $math = new MathRenderer( $tex );
 270                 $math->setOutputMode( $wgUser->getOption('math'));
 271                 return $math->render();
 272         }
 273 }
 274 ?>