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, $params=array() ) {
  24                 $this->tex = $tex;
  25                 $this->params = $params;
  26         }
  27
  28         function setOutputMode( $mode ) {
  29                 $this->mode = $mode;
  30         }
  31
  32         function render() {
  33                 global $wgTmpDirectory, $wgInputEncoding;
  34                 global $wgTexvc;
  35                 $fname = 'MathRenderer::render';
  36
  37                 if( $this->mode == MW_MATH_SOURCE ) {
  38                         # No need to render or parse anything more!
  39                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  40                 }
  41                 if( $this->tex == '' ) {
  42                         return; # bug 8372
  43                 }
  44
  45                 if( !$this->_recall() ) {
  46                         # Ensure that the temp and output directories are available before continuing...
  47                         if( !file_exists( $wgTmpDirectory ) ) {
  48                                 if( !@mkdir( $wgTmpDirectory ) ) {
  49                                         return $this->_error( 'math_bad_tmpdir' );
  50                                 }
  51                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  52                                 return $this->_error( 'math_bad_tmpdir' );
  53                         }
  54
  55                         if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  56                                 return $this->_error( 'math_notexvc' );
  57                         }
  58                         $cmd = $wgTexvc . ' ' .
  59                                         escapeshellarg( $wgTmpDirectory ).' '.
  60                                         escapeshellarg( $wgTmpDirectory ).' '.
  61                                         escapeshellarg( $this->tex ).' '.
  62                                         escapeshellarg( $wgInputEncoding );
  63
  64                         if ( wfIsWindows() ) {
  65                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  66                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  67                         }
  68
  69                         wfDebug( "TeX: $cmd\n" );
  70                         $contents = `$cmd`;
  71                         wfDebug( "TeX output:\n $contents\n---\n" );
  72
  73                         if (strlen($contents) == 0) {
  74                                 return $this->_error( 'math_unknown_error' );
  75                         }
  76
  77                         $retval = substr ($contents, 0, 1);
  78                         $errmsg = '';
  79                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  80                                 if ($retval == 'C') {
  81                                         $this->conservativeness = 2;
  82                                 } else if ($retval == 'M') {
  83                                         $this->conservativeness = 1;
  84                                 } else {
  85                                         $this->conservativeness = 0;
  86                                 }
  87                                 $outdata = substr ($contents, 33);
  88
  89                                 $i = strpos($outdata, "\000");
  90
  91                                 $this->html = substr($outdata, 0, $i);
  92                                 $this->mathml = substr($outdata, $i+1);
  93                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  94                                 $this->html = substr ($contents, 33);
  95                                 if ($retval == 'c') {
  96                                         $this->conservativeness = 2;
  97                                 } else if ($retval == 'm') {
  98                                         $this->conservativeness = 1;
  99                                 } else {
 100                                         $this->conservativeness = 0;
 101                                 }
 102                                 $this->mathml = NULL;
 103                         } else if ($retval == 'X') {
 104                                 $this->html = NULL;
 105                                 $this->mathml = substr ($contents, 33);
 106                                 $this->conservativeness = 0;
 107                         } else if ($retval == '+') {
 108                                 $this->html = NULL;
 109                                 $this->mathml = NULL;
 110                                 $this->conservativeness = 0;
 111                         } else {
 112                                 $errbit = htmlspecialchars( substr($contents, 1) );
 113                                 switch( $retval ) {
 114                                         case 'E':
 115                                                 $errmsg = $this->_error( 'math_lexing_error', $errbit );
 116                                                 break;
 117                                         case 'S':
 118                                                 $errmsg = $this->_error( 'math_syntax_error', $errbit );
 119                                                 break;
 120                                         case 'F':
 121                                                 $errmsg = $this->_error( 'math_unknown_function', $errbit );
 122                                                 break;
 123                                         default:
 124                                                 $errmsg = $this->_error( 'math_unknown_error', $errbit );
 125                                 }
 126                         }
 127
 128                         if ( !$errmsg ) {
 129                                  $this->hash = substr ($contents, 1, 32);
 130                         }
 131
 132                         wfRunHooks( 'MathAfterTexvc', array( &$this, &$errmsg ) );
 133
 134                         if ( $errmsg ) {
 135                                  return $errmsg;
 136                         }
 137
 138                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 139                                 return $this->_error( 'math_unknown_error' );
 140                         }
 141
 142                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 143                                 return $this->_error( 'math_image_error' );
 144                         }
 145
 146                         $hashpath = $this->_getHashPath();
 147                         if( !file_exists( $hashpath ) ) {
 148                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 149                                         return $this->_error( 'math_bad_output' );
 150                                 }
 151                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 152                                 return $this->_error( 'math_bad_output' );
 153                         }
 154
 155                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 156                                 return $this->_error( 'math_output_error' );
 157                         }
 158
 159                         # Now save it back to the DB:
 160                         if ( !wfReadOnly() ) {
 161                                 $outmd5_sql = pack('H32', $this->hash);
 162
 163                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 164
 165                                 $dbw = wfGetDB( DB_MASTER );
 166                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 167                                   array(
 168                                         'math_inputhash' => $dbw->encodeBlob($md5_sql),
 169                                         'math_outputhash' => $dbw->encodeBlob($outmd5_sql),
 170                                         'math_html_conservativeness' => $this->conservativeness,
 171                                         'math_html' => $this->html,
 172                                         'math_mathml' => $this->mathml,
 173                                   ), $fname, array( 'IGNORE' )
 174                                 );
 175                         }
 176
 177                 }
 178
 179                 return $this->_doRender();
 180         }
 181
 182         function _error( $msg, $append = '' ) {
 183                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 184                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 185                 $source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
 186                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 187         }
 188
 189         function _recall() {
 190                 global $wgMathDirectory;
 191                 $fname = 'MathRenderer::_recall';
 192
 193                 $this->md5 = md5( $this->tex );
 194                 $dbr = wfGetDB( DB_SLAVE );
 195                 $rpage = $dbr->selectRow( 'math',
 196                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 197                         array( 'math_inputhash' => $dbr->encodeBlob(pack("H32", $this->md5))), # Binary packed, not hex
 198                         $fname
 199                 );
 200
 201                 if( $rpage !== false ) {
 202                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 203                         $xhash = unpack( 'H32md5', $dbr->decodeBlob($rpage->math_outputhash) . "                " );
 204                         $this->hash = $xhash ['md5'];
 205
 206                         $this->conservativeness = $rpage->math_html_conservativeness;
 207                         $this->html = $rpage->math_html;
 208                         $this->mathml = $rpage->math_mathml;
 209
 210                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 211                                 return true;
 212                         }
 213
 214                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 215                                 $hashpath = $this->_getHashPath();
 216
 217                                 if( !file_exists( $hashpath ) ) {
 218                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 219                                                 return false;
 220                                         }
 221                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 222                                         return false;
 223                                 }
 224                                 if ( function_exists( "link" ) ) {
 225                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 226                                                         $hashpath . "/{$this->hash}.png" );
 227                                 } else {
 228                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 229                                                         $hashpath . "/{$this->hash}.png" );
 230                                 }
 231                         }
 232
 233                 }
 234
 235                 # Missing from the database and/or the render cache
 236                 return false;
 237         }
 238
 239         /**
 240          * Select among PNG, HTML, or MathML output depending on
 241          */
 242         function _doRender() {
 243                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 244                         return Xml::tags( 'math',
 245                                 $this->_attribs( 'math',
 246                                         array( 'xmlns' => 'http://www.w3.org/1998/Math/MathML' ) ),
 247                                 $this->mathml );
 248                 }
 249                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 250                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 251                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 252                         return $this->_linkToMathImage();
 253                 } else {
 254                         return Xml::tags( 'span',
 255                                 $this->_attribs( 'span',
 256                                         array( 'class' => 'texhtml' ) ),
 257                                 $this->html );
 258                 }
 259         }
 260
 261         function _attribs( $tag, $defaults=array(), $overrides=array() ) {
 262                 $attribs = Sanitizer::validateTagAttributes( $this->params, $tag );
 263                 $attribs = Sanitizer::mergeAttributes( $defaults, $attribs );
 264                 $attribs = Sanitizer::mergeAttributes( $attribs, $overrides );
 265                 return $attribs;
 266         }
 267
 268         function _linkToMathImage() {
 269                 global $wgMathPath;
 270                 $url = "$wgMathPath/" . substr($this->hash, 0, 1)
 271                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 272                                         . "/{$this->hash}.png";
 273
 274                 return Xml::element( 'img',
 275                         $this->_attribs(
 276                                 'img',
 277                                 array(
 278                                         'class' => 'tex',
 279                                         'alt' => $this->tex ),
 280                                 array(
 281                                         'src' => $url ) ) );
 282         }
 283
 284         function _getHashPath() {
 285                 global $wgMathDirectory;
 286                 $path = $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 287                                         .'/'. substr($this->hash, 1, 1)
 288                                         .'/'. substr($this->hash, 2, 1);
 289                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 290                 return $path;
 291         }
 292
 293         public static function renderMath( $tex, $params=array() ) {
 294                 global $wgUser;
 295                 $math = new MathRenderer( $tex, $params );
 296                 $math->setOutputMode( $wgUser->getOption('math'));
 297                 return $math->render();
 298         }
 299 }
 300