includes/Math.php

   1 <?php
   2 /**
   3  * Contain everything related to <math> </math> parsing
   4  * @file
   5  * @ingroup Parser
   6  */
   7
   8 /**
   9  * Takes LaTeX fragments, sends them to a helper program (texvc) for rendering
  10  * to rasterized PNG and HTML and MathML approximations. An appropriate
  11  * rendering form is picked and returned.
  12  *
  13  * @author Tomasz Wegrzanowski, with additions by Brion Vibber (2003, 2004)
  14  * @ingroup Parser
  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 __construct( $tex, $params=array() ) {
  26                 $this->tex = $tex;
  27                 $this->params = $params;
  28         }
  29
  30         function setOutputMode( $mode ) {
  31                 $this->mode = $mode;
  32         }
  33
  34         function render() {
  35                 global $wgTmpDirectory, $wgInputEncoding;
  36                 global $wgTexvc;
  37                 $fname = 'MathRenderer::render';
  38
  39                 if( $this->mode == MW_MATH_SOURCE ) {
  40                         # No need to render or parse anything more!
  41                         return ('$ '.htmlspecialchars( $this->tex ).' $');
  42                 }
  43                 if( $this->tex == '' ) {
  44                         return; # bug 8372
  45                 }
  46
  47                 if( !$this->_recall() ) {
  48                         # Ensure that the temp and output directories are available before continuing...
  49                         if( !file_exists( $wgTmpDirectory ) ) {
  50                                 if( !@mkdir( $wgTmpDirectory ) ) {
  51                                         return $this->_error( 'math_bad_tmpdir' );
  52                                 }
  53                         } elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
  54                                 return $this->_error( 'math_bad_tmpdir' );
  55                         }
  56
  57                         if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
  58                                 return $this->_error( 'math_notexvc' );
  59                         }
  60                         $cmd = $wgTexvc . ' ' .
  61                                         escapeshellarg( $wgTmpDirectory ).' '.
  62                                         escapeshellarg( $wgTmpDirectory ).' '.
  63                                         escapeshellarg( $this->tex ).' '.
  64                                         escapeshellarg( $wgInputEncoding );
  65
  66                         if ( wfIsWindows() ) {
  67                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  68                                 $cmd = 'sh -c ' . wfEscapeShellArg( $cmd );
  69                         }
  70
  71                         wfDebug( "TeX: $cmd\n" );
  72                         $contents = `$cmd`;
  73                         wfDebug( "TeX output:\n $contents\n---\n" );
  74
  75                         if (strlen($contents) == 0) {
  76                                 return $this->_error( 'math_unknown_error' );
  77                         }
  78
  79                         $retval = substr ($contents, 0, 1);
  80                         $errmsg = '';
  81                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  82                                 if ($retval == 'C') {
  83                                         $this->conservativeness = 2;
  84                                 } else if ($retval == 'M') {
  85                                         $this->conservativeness = 1;
  86                                 } else {
  87                                         $this->conservativeness = 0;
  88                                 }
  89                                 $outdata = substr ($contents, 33);
  90
  91                                 $i = strpos($outdata, "\000");
  92
  93                                 $this->html = substr($outdata, 0, $i);
  94                                 $this->mathml = substr($outdata, $i+1);
  95                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  96                                 $this->html = substr ($contents, 33);
  97                                 if ($retval == 'c') {
  98                                         $this->conservativeness = 2;
  99                                 } else if ($retval == 'm') {
 100                                         $this->conservativeness = 1;
 101                                 } else {
 102                                         $this->conservativeness = 0;
 103                                 }
 104                                 $this->mathml = NULL;
 105                         } else if ($retval == 'X') {
 106                                 $this->html = NULL;
 107                                 $this->mathml = substr ($contents, 33);
 108                                 $this->conservativeness = 0;
 109                         } else if ($retval == '+') {
 110                                 $this->html = NULL;
 111                                 $this->mathml = NULL;
 112                                 $this->conservativeness = 0;
 113                         } else {
 114                                 $errbit = htmlspecialchars( substr($contents, 1) );
 115                                 switch( $retval ) {
 116                                         case 'E':
 117                                                 $errmsg = $this->_error( 'math_lexing_error', $errbit );
 118                                                 break;
 119                                         case 'S':
 120                                                 $errmsg = $this->_error( 'math_syntax_error', $errbit );
 121                                                 break;
 122                                         case 'F':
 123                                                 $errmsg = $this->_error( 'math_unknown_function', $errbit );
 124                                                 break;
 125                                         default:
 126                                                 $errmsg = $this->_error( 'math_unknown_error', $errbit );
 127                                 }
 128                         }
 129
 130                         if ( !$errmsg ) {
 131                                  $this->hash = substr ($contents, 1, 32);
 132                         }
 133
 134                         wfRunHooks( 'MathAfterTexvc', array( &$this, &$errmsg ) );
 135
 136                         if ( $errmsg ) {
 137                                  return $errmsg;
 138                         }
 139
 140                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 141                                 return $this->_error( 'math_unknown_error' );
 142                         }
 143
 144                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 145                                 return $this->_error( 'math_image_error' );
 146                         }
 147
 148                         $hashpath = $this->_getHashPath();
 149                         if( !file_exists( $hashpath ) ) {
 150                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 151                                         return $this->_error( 'math_bad_output' );
 152                                 }
 153                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 154                                 return $this->_error( 'math_bad_output' );
 155                         }
 156
 157                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 158                                 return $this->_error( 'math_output_error' );
 159                         }
 160
 161                         # Now save it back to the DB:
 162                         if ( !wfReadOnly() ) {
 163                                 $outmd5_sql = pack('H32', $this->hash);
 164
 165                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 166
 167                                 $dbw = wfGetDB( DB_MASTER );
 168                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 169                                   array(
 170                                         'math_inputhash' => $dbw->encodeBlob($md5_sql),
 171                                         'math_outputhash' => $dbw->encodeBlob($outmd5_sql),
 172                                         'math_html_conservativeness' => $this->conservativeness,
 173                                         'math_html' => $this->html,
 174                                         'math_mathml' => $this->mathml,
 175                                   ), $fname, array( 'IGNORE' )
 176                                 );
 177                         }
 178
 179                 }
 180
 181                 return $this->_doRender();
 182         }
 183
 184         function _error( $msg, $append = '' ) {
 185                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 186                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 187                 $source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
 188                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 189         }
 190
 191         function _recall() {
 192                 global $wgMathDirectory;
 193                 $fname = 'MathRenderer::_recall';
 194
 195                 $this->md5 = md5( $this->tex );
 196                 $dbr = wfGetDB( DB_SLAVE );
 197                 $rpage = $dbr->selectRow( 'math',
 198                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 199                         array( 'math_inputhash' => $dbr->encodeBlob(pack("H32", $this->md5))), # Binary packed, not hex
 200                         $fname
 201                 );
 202
 203                 if( $rpage !== false ) {
 204                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 205                         $xhash = unpack( 'H32md5', $dbr->decodeBlob($rpage->math_outputhash) . "                " );
 206                         $this->hash = $xhash ['md5'];
 207
 208                         $this->conservativeness = $rpage->math_html_conservativeness;
 209                         $this->html = $rpage->math_html;
 210                         $this->mathml = $rpage->math_mathml;
 211
 212                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 213                                 return true;
 214                         }
 215
 216                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 217                                 $hashpath = $this->_getHashPath();
 218
 219                                 if( !file_exists( $hashpath ) ) {
 220                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 221                                                 return false;
 222                                         }
 223                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 224                                         return false;
 225                                 }
 226                                 if ( function_exists( "link" ) ) {
 227                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 228                                                         $hashpath . "/{$this->hash}.png" );
 229                                 } else {
 230                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 231                                                         $hashpath . "/{$this->hash}.png" );
 232                                 }
 233                         }
 234
 235                 }
 236
 237                 # Missing from the database and/or the render cache
 238                 return false;
 239         }
 240
 241         /**
 242          * Select among PNG, HTML, or MathML output depending on
 243          */
 244         function _doRender() {
 245                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 246                         return Xml::tags( 'math',
 247                                 $this->_attribs( 'math',
 248                                         array( 'xmlns' => 'http://www.w3.org/1998/Math/MathML' ) ),
 249                                 $this->mathml );
 250                 }
 251                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 252                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 253                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 254                         return $this->_linkToMathImage();
 255                 } else {
 256                         return Xml::tags( 'span',
 257                                 $this->_attribs( 'span',
 258                                         array( 'class' => 'texhtml' ) ),
 259                                 $this->html );
 260                 }
 261         }
 262
 263         function _attribs( $tag, $defaults=array(), $overrides=array() ) {
 264                 $attribs = Sanitizer::validateTagAttributes( $this->params, $tag );
 265                 $attribs = Sanitizer::mergeAttributes( $defaults, $attribs );
 266                 $attribs = Sanitizer::mergeAttributes( $attribs, $overrides );
 267                 return $attribs;
 268         }
 269
 270         function _linkToMathImage() {
 271                 global $wgMathPath;
 272                 $url = "$wgMathPath/" . substr($this->hash, 0, 1)
 273                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 274                                         . "/{$this->hash}.png";
 275
 276                 return Xml::element( 'img',
 277                         $this->_attribs(
 278                                 'img',
 279                                 array(
 280                                         'class' => 'tex',
 281                                         'alt' => $this->tex ),
 282                                 array(
 283                                         'src' => $url ) ) );
 284         }
 285
 286         function _getHashPath() {
 287                 global $wgMathDirectory;
 288                 $path = $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 289                                         .'/'. substr($this->hash, 1, 1)
 290                                         .'/'. substr($this->hash, 2, 1);
 291                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 292                 return $path;
 293         }
 294
 295         public static function renderMath( $tex, $params=array() ) {
 296                 global $wgUser;
 297                 $math = new MathRenderer( $tex, $params );
 298                 $math->setOutputMode( $wgUser->getOption('math'));
 299                 return $math->render();
 300         }
 301 }