includes/Math.php

   1 <?php
   2 /**
   3  * Contain everything related to <math> </math> parsing
   4  */
   5
   6 /**
   7  * Takes LaTeX fragments, sends them to a helper program (texvc) for rendering
   8  * to rasterized PNG and HTML and MathML approximations. An appropriate
   9  * rendering form is picked and returned.
  10  *
  11  * by Tomasz Wegrzanowski, with additions by Brion Vibber (2003, 2004)
  12  *
  13  */
  14 class MathRenderer {
  15         var $mode = MW_MATH_MODERN;
  16         var $tex = '';
  17         var $inputhash = '';
  18         var $hash = '';
  19         var $html = '';
  20         var $mathml = '';
  21         var $conservativeness = 0;
  22
  23         function __construct( $tex ) {
  24                 $this->tex = $tex;
  25         }
  26
  27         function setOutputMode( $mode ) {
  28                 $this->mode = $mode;
  29         }
  30
  31         function render() {
  32                 global $wgTmpDirectory, $wgInputEncoding;
  33                 global $wgTexvc;
  34                 $fname = 'MathRenderer::render';
  35
  36                 if( $this->mode == MW_MATH_SOURCE ) {
  37                         # No need to render or parse anything more!
  38                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  39                 }
  40                 if( $this->tex == '' ) {
  41                         return; # bug 8372
  42                 }
  43
  44                 if( !$this->_recall() ) {
  45                         # Ensure that the temp and output directories are available before continuing...
  46                         if( !file_exists( $wgTmpDirectory ) ) {
  47                                 if( !@mkdir( $wgTmpDirectory ) ) {
  48                                         return $this->_error( 'math_bad_tmpdir' );
  49                                 }
  50                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  51                                 return $this->_error( 'math_bad_tmpdir' );
  52                         }
  53
  54                         if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  55                                 return $this->_error( 'math_notexvc' );
  56                         }
  57                         $cmd = $wgTexvc . ' ' .
  58                                         escapeshellarg( $wgTmpDirectory ).' '.
  59                                         escapeshellarg( $wgTmpDirectory ).' '.
  60                                         escapeshellarg( $this->tex ).' '.
  61                                         escapeshellarg( $wgInputEncoding );
  62
  63                         if ( wfIsWindows() ) {
  64                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  65                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  66                         }
  67
  68                         wfDebug( "TeX: $cmd\n" );
  69                         $contents = `$cmd`;
  70                         wfDebug( "TeX output:\n $contents\n---\n" );
  71
  72                         if (strlen($contents) == 0) {
  73                                 return $this->_error( 'math_unknown_error' );
  74                         }
  75
  76                         $retval = substr ($contents, 0, 1);
  77                         $errmsg = '';
  78                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  79                                 if ($retval == 'C') {
  80                                         $this->conservativeness = 2;
  81                                 } else if ($retval == 'M') {
  82                                         $this->conservativeness = 1;
  83                                 } else {
  84                                         $this->conservativeness = 0;
  85                                 }
  86                                 $outdata = substr ($contents, 33);
  87
  88                                 $i = strpos($outdata, "\000");
  89
  90                                 $this->html = substr($outdata, 0, $i);
  91                                 $this->mathml = substr($outdata, $i+1);
  92                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  93                                 $this->html = substr ($contents, 33);
  94                                 if ($retval == 'c') {
  95                                         $this->conservativeness = 2;
  96                                 } else if ($retval == 'm') {
  97                                         $this->conservativeness = 1;
  98                                 } else {
  99                                         $this->conservativeness = 0;
 100                                 }
 101                                 $this->mathml = NULL;
 102                         } else if ($retval == 'X') {
 103                                 $this->html = NULL;
 104                                 $this->mathml = substr ($contents, 33);
 105                                 $this->conservativeness = 0;
 106                         } else if ($retval == '+') {
 107                                 $this->html = NULL;
 108                                 $this->mathml = NULL;
 109                                 $this->conservativeness = 0;
 110                         } else {
 111                                 $errbit = htmlspecialchars( substr($contents, 1) );
 112                                 switch( $retval ) {
 113                                         case 'E': $errmsg = $this->_error( 'math_lexing_error', $errbit );
 114                                         case 'S': $errmsg = $this->_error( 'math_syntax_error', $errbit );
 115                                         case 'F': $errmsg = $this->_error( 'math_unknown_function', $errbit );
 116                                         default:  $errmsg = $this->_error( 'math_unknown_error', $errbit );
 117                                 }
 118                         }
 119
 120                         if ( !$errmsg ) {
 121                                  $this->hash = substr ($contents, 1, 32);
 122                         }
 123
 124                         wfRunHooks( 'MathAfterTexvc', array( &$this, &$errmsg ) );
 125
 126                         if ( $errmsg ) {
 127                                  return $errmsg;
 128                         }
 129
 130                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 131                                 return $this->_error( 'math_unknown_error' );
 132                         }
 133
 134                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 135                                 return $this->_error( 'math_image_error' );
 136                         }
 137
 138                         $hashpath = $this->_getHashPath();
 139                         if( !file_exists( $hashpath ) ) {
 140                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 141                                         return $this->_error( 'math_bad_output' );
 142                                 }
 143                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 144                                 return $this->_error( 'math_bad_output' );
 145                         }
 146
 147                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 148                                 return $this->_error( 'math_output_error' );
 149                         }
 150
 151                         # Now save it back to the DB:
 152                         if ( !wfReadOnly() ) {
 153                                 $outmd5_sql = pack('H32', $this->hash);
 154
 155                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 156
 157                                 $dbw = wfGetDB( DB_MASTER );
 158                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 159                                   array(
 160                                         'math_inputhash' => $md5_sql,
 161                                         'math_outputhash' => $outmd5_sql,
 162                                         'math_html_conservativeness' => $this->conservativeness,
 163                                         'math_html' => $this->html,
 164                                         'math_mathml' => $this->mathml,
 165                                   ), $fname, array( 'IGNORE' )
 166                                 );
 167                         }
 168
 169                 }
 170
 171                 return $this->_doRender();
 172         }
 173
 174         function _error( $msg, $append = '' ) {
 175                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 176                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 177                 $source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
 178                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 179         }
 180
 181         function _recall() {
 182                 global $wgMathDirectory;
 183                 $fname = 'MathRenderer::_recall';
 184
 185                 $this->md5 = md5( $this->tex );
 186                 $dbr = wfGetDB( DB_SLAVE );
 187                 $rpage = $dbr->selectRow( 'math',
 188                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 189                         array( 'math_inputhash' => pack("H32", $this->md5)), # Binary packed, not hex
 190                         $fname
 191                 );
 192
 193                 if( $rpage !== false ) {
 194                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 195                         $xhash = unpack( 'H32md5', $rpage->math_outputhash . "                " );
 196                         $this->hash = $xhash ['md5'];
 197
 198                         $this->conservativeness = $rpage->math_html_conservativeness;
 199                         $this->html = $rpage->math_html;
 200                         $this->mathml = $rpage->math_mathml;
 201
 202                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 203                                 return true;
 204                         }
 205
 206                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 207                                 $hashpath = $this->_getHashPath();
 208
 209                                 if( !file_exists( $hashpath ) ) {
 210                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 211                                                 return false;
 212                                         }
 213                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 214                                         return false;
 215                                 }
 216                                 if ( function_exists( "link" ) ) {
 217                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 218                                                         $hashpath . "/{$this->hash}.png" );
 219                                 } else {
 220                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 221                                                         $hashpath . "/{$this->hash}.png" );
 222                                 }
 223                         }
 224
 225                 }
 226
 227                 # Missing from the database and/or the render cache
 228                 return false;
 229         }
 230
 231         /**
 232          * Select among PNG, HTML, or MathML output depending on
 233          */
 234         function _doRender() {
 235                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 236                         return "<math xmlns='http://www.w3.org/1998/Math/MathML'>{$this->mathml}</math>";
 237                 }
 238                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 239                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 240                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 241                         return $this->_linkToMathImage();
 242                 } else {
 243                         return '<span class="texhtml">'.$this->html.'</span>';
 244                 }
 245         }
 246
 247         function _linkToMathImage() {
 248                 global $wgMathPath;
 249                 $url = htmlspecialchars( "$wgMathPath/" . substr($this->hash, 0, 1)
 250                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 251                                         . "/{$this->hash}.png" );
 252                 $alt = trim(str_replace("\n", ' ', htmlspecialchars( $this->tex )));
 253                 return "<img class='tex' src=\"$url\" alt=\"$alt\" />";
 254         }
 255
 256         function _getHashPath() {
 257                 global $wgMathDirectory;
 258                 $path = $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 259                                         .'/'. substr($this->hash, 1, 1)
 260                                         .'/'. substr($this->hash, 2, 1);
 261                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 262                 return $path;
 263         }
 264
 265         public static function renderMath( $tex ) {
 266                 global $wgUser;
 267                 $math = new MathRenderer( $tex );
 268                 $math->setOutputMode( $wgUser->getOption('math'));
 269                 return $math->render();
 270         }
 271 }
 272 ?>