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