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( !wfMkdirParents( $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                         $delim = wfIsWindows() ? "' '" : ' ';
  61                         $cmd = wfEscapeShellArg( $wgTexvc ) . $delim .
  62                                         wfEscapeShellArg( $wgTmpDirectory ) . $delim .
  63                                         wfEscapeShellArg( $wgTmpDirectory ) . $delim .
  64                                         wfEscapeShellArg( $this->tex ) . $delim .
  65                                         wfEscapeShellArg( $wgInputEncoding );
  66
  67                         if ( wfIsWindows() ) {
  68                                 # Invoke it within cygwin sh, because texvc expects sh features in its default shell
  69                                 $cmd = "sh -c $cmd";
  70                         }
  71
  72                         wfDebug( "TeX: $cmd\n" );
  73                         $contents = `$cmd`;
  74                         wfDebug( "TeX output:\n $contents\n---\n" );
  75
  76                         if (strlen($contents) == 0) {
  77                                 return $this->_error( 'math_unknown_error' );
  78                         }
  79
  80                         $retval = substr ($contents, 0, 1);
  81                         $errmsg = '';
  82                         if (($retval == 'C') || ($retval == 'M') || ($retval == 'L')) {
  83                                 if ($retval == 'C') {
  84                                         $this->conservativeness = 2;
  85                                 } else if ($retval == 'M') {
  86                                         $this->conservativeness = 1;
  87                                 } else {
  88                                         $this->conservativeness = 0;
  89                                 }
  90                                 $outdata = substr ($contents, 33);
  91
  92                                 $i = strpos($outdata, "\000");
  93
  94                                 $this->html = substr($outdata, 0, $i);
  95                                 $this->mathml = substr($outdata, $i+1);
  96                         } else if (($retval == 'c') || ($retval == 'm') || ($retval == 'l'))  {
  97                                 $this->html = substr ($contents, 33);
  98                                 if ($retval == 'c') {
  99                                         $this->conservativeness = 2;
 100                                 } else if ($retval == 'm') {
 101                                         $this->conservativeness = 1;
 102                                 } else {
 103                                         $this->conservativeness = 0;
 104                                 }
 105                                 $this->mathml = NULL;
 106                         } else if ($retval == 'X') {
 107                                 $this->html = NULL;
 108                                 $this->mathml = substr ($contents, 33);
 109                                 $this->conservativeness = 0;
 110                         } else if ($retval == '+') {
 111                                 $this->html = NULL;
 112                                 $this->mathml = NULL;
 113                                 $this->conservativeness = 0;
 114                         } else {
 115                                 $errbit = htmlspecialchars( substr($contents, 1) );
 116                                 switch( $retval ) {
 117                                         case 'E':
 118                                                 $errmsg = $this->_error( 'math_lexing_error', $errbit );
 119                                                 break;
 120                                         case 'S':
 121                                                 $errmsg = $this->_error( 'math_syntax_error', $errbit );
 122                                                 break;
 123                                         case 'F':
 124                                                 $errmsg = $this->_error( 'math_unknown_function', $errbit );
 125                                                 break;
 126                                         default:
 127                                                 $errmsg = $this->_error( 'math_unknown_error', $errbit );
 128                                 }
 129                         }
 130
 131                         if ( !$errmsg ) {
 132                                  $this->hash = substr ($contents, 1, 32);
 133                         }
 134
 135                         wfRunHooks( 'MathAfterTexvc', array( &$this, &$errmsg ) );
 136
 137                         if ( $errmsg ) {
 138                                  return $errmsg;
 139                         }
 140
 141                         if (!preg_match("/^[a-f0-9]{32}$/", $this->hash)) {
 142                                 return $this->_error( 'math_unknown_error' );
 143                         }
 144
 145                         if( !file_exists( "$wgTmpDirectory/{$this->hash}.png" ) ) {
 146                                 return $this->_error( 'math_image_error' );
 147                         }
 148
 149                         $hashpath = $this->_getHashPath();
 150                         if( !file_exists( $hashpath ) ) {
 151                                 if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 152                                         return $this->_error( 'math_bad_output' );
 153                                 }
 154                         } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 155                                 return $this->_error( 'math_bad_output' );
 156                         }
 157
 158                         if( !rename( "$wgTmpDirectory/{$this->hash}.png", "$hashpath/{$this->hash}.png" ) ) {
 159                                 return $this->_error( 'math_output_error' );
 160                         }
 161
 162                         # Now save it back to the DB:
 163                         if ( !wfReadOnly() ) {
 164                                 $outmd5_sql = pack('H32', $this->hash);
 165
 166                                 $md5_sql = pack('H32', $this->md5); # Binary packed, not hex
 167
 168                                 $dbw = wfGetDB( DB_MASTER );
 169                                 $dbw->replace( 'math', array( 'math_inputhash' ),
 170                                   array(
 171                                         'math_inputhash' => $dbw->encodeBlob($md5_sql),
 172                                         'math_outputhash' => $dbw->encodeBlob($outmd5_sql),
 173                                         'math_html_conservativeness' => $this->conservativeness,
 174                                         'math_html' => $this->html,
 175                                         'math_mathml' => $this->mathml,
 176                                   ), $fname
 177                                 );
 178                         }
 179
 180                 }
 181
 182                 return $this->_doRender();
 183         }
 184
 185         function _error( $msg, $append = '' ) {
 186                 $mf   = htmlspecialchars( wfMsg( 'math_failure' ) );
 187                 $errmsg = htmlspecialchars( wfMsg( $msg ) );
 188                 $source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
 189                 return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
 190         }
 191
 192         function _recall() {
 193                 global $wgMathDirectory;
 194                 $fname = 'MathRenderer::_recall';
 195
 196                 $this->md5 = md5( $this->tex );
 197                 $dbr = wfGetDB( DB_SLAVE );
 198                 $rpage = $dbr->selectRow( 'math',
 199                         array( 'math_outputhash','math_html_conservativeness','math_html','math_mathml' ),
 200                         array( 'math_inputhash' => $dbr->encodeBlob(pack("H32", $this->md5))), # Binary packed, not hex
 201                         $fname
 202                 );
 203
 204                 if( $rpage !== false ) {
 205                         # Tailing 0x20s can get dropped by the database, add it back on if necessary:
 206                         $xhash = unpack( 'H32md5', $dbr->decodeBlob($rpage->math_outputhash) . "                " );
 207                         $this->hash = $xhash ['md5'];
 208
 209                         $this->conservativeness = $rpage->math_html_conservativeness;
 210                         $this->html = $rpage->math_html;
 211                         $this->mathml = $rpage->math_mathml;
 212
 213                         if( file_exists( $this->_getHashPath() . "/{$this->hash}.png" ) ) {
 214                                 return true;
 215                         }
 216
 217                         if( file_exists( $wgMathDirectory . "/{$this->hash}.png" ) ) {
 218                                 $hashpath = $this->_getHashPath();
 219
 220                                 if( !file_exists( $hashpath ) ) {
 221                                         if( !@wfMkdirParents( $hashpath, 0755 ) ) {
 222                                                 return false;
 223                                         }
 224                                 } elseif( !is_dir( $hashpath ) || !is_writable( $hashpath ) ) {
 225                                         return false;
 226                                 }
 227                                 if ( function_exists( "link" ) ) {
 228                                         return link ( $wgMathDirectory . "/{$this->hash}.png",
 229                                                         $hashpath . "/{$this->hash}.png" );
 230                                 } else {
 231                                         return rename ( $wgMathDirectory . "/{$this->hash}.png",
 232                                                         $hashpath . "/{$this->hash}.png" );
 233                                 }
 234                         }
 235
 236                 }
 237
 238                 # Missing from the database and/or the render cache
 239                 return false;
 240         }
 241
 242         /**
 243          * Select among PNG, HTML, or MathML output depending on
 244          */
 245         function _doRender() {
 246                 if( $this->mode == MW_MATH_MATHML && $this->mathml != '' ) {
 247                         return Xml::tags( 'math',
 248                                 $this->_attribs( 'math',
 249                                         array( 'xmlns' => 'http://www.w3.org/1998/Math/MathML' ) ),
 250                                 $this->mathml );
 251                 }
 252                 if (($this->mode == MW_MATH_PNG) || ($this->html == '') ||
 253                    (($this->mode == MW_MATH_SIMPLE) && ($this->conservativeness != 2)) ||
 254                    (($this->mode == MW_MATH_MODERN || $this->mode == MW_MATH_MATHML) && ($this->conservativeness == 0))) {
 255                         return $this->_linkToMathImage();
 256                 } else {
 257                         return Xml::tags( 'span',
 258                                 $this->_attribs( 'span',
 259                                         array( 'class' => 'texhtml' ) ),
 260                                 $this->html );
 261                 }
 262         }
 263
 264         function _attribs( $tag, $defaults=array(), $overrides=array() ) {
 265                 $attribs = Sanitizer::validateTagAttributes( $this->params, $tag );
 266                 $attribs = Sanitizer::mergeAttributes( $defaults, $attribs );
 267                 $attribs = Sanitizer::mergeAttributes( $attribs, $overrides );
 268                 return $attribs;
 269         }
 270
 271         function _linkToMathImage() {
 272                 global $wgMathPath;
 273                 $url = "$wgMathPath/" . substr($this->hash, 0, 1)
 274                                         .'/'. substr($this->hash, 1, 1) .'/'. substr($this->hash, 2, 1)
 275                                         . "/{$this->hash}.png";
 276
 277                 return Xml::element( 'img',
 278                         $this->_attribs(
 279                                 'img',
 280                                 array(
 281                                         'class' => 'tex',
 282                                         'alt' => $this->tex ),
 283                                 array(
 284                                         'src' => $url ) ) );
 285         }
 286
 287         function _getHashPath() {
 288                 global $wgMathDirectory;
 289                 $path = $wgMathDirectory .'/'. substr($this->hash, 0, 1)
 290                                         .'/'. substr($this->hash, 1, 1)
 291                                         .'/'. substr($this->hash, 2, 1);
 292                 wfDebug( "TeX: getHashPath, hash is: $this->hash, path is: $path\n" );
 293                 return $path;
 294         }
 295
 296         public static function renderMath( $tex, $params=array() ) {
 297                 global $wgUser;
 298                 $math = new MathRenderer( $tex, $params );
 299                 $math->setOutputMode( $wgUser->getOption('math'));
 300                 return $math->render();
 301         }
 302 }