mediawiki-extensions-Math/MathRenderer.php

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<?php
/**
* MediaWiki math extension
*
* (c) 2002-2012 Tomasz Wegrzanowski, Brion Vibber, Moritz Schubotz, and other MediaWiki contributors
* GPLv2 license; info in main package.
*
* @file
*/
/**
* Abstract base class with static methods for rendering the <math> tags using
* different technologies. These static methods create a new instance of the
* extending classes and render the math tags based on the mode setting of the user.
* Furthermore this class handles the caching of the rendered output and provides
* debug information,
* if run in mathdebug mode.
*
* @author Tomasz Wegrzanowski
* @author Brion Vibber
* @author Moritz Schubotz
*/
abstract class MathRenderer {
/**
* The following variables should made private, as soon it can be verified
* that they are not being directly accessed by other extensions.
*/
var $mode = MW_MATH_PNG;
var $tex = '';
/**
* is calculated by texvc.
* @var string
*/
var $hash = '';
var $html = '';
var $mathml = '';
var $conservativeness = 0;
var $params = '';
protected $recall;
/**
* Constructs a base MathRenderer
*
* @param string $tex (optional) LaTeX markup
* @param array $params (optional) HTML attributes
*/
public function __construct( $tex='', $params = array() ) {
$this->tex = $tex;
$this->params = $params;
}
/**
* Static method for rendering math tag
*
* @param string $tex LaTeX markup
* @param array $params HTML attributes
* @param int $mode constant indicating rendering mode
* @return string HTML for math tag
*/
public static function renderMath( $tex, $params = array(), $mode = MW_MATH_PNG ) {
$renderer = self::getRenderer( $tex, $params, $mode );
return $renderer->render();
}
/**
* Static factory method for getting a renderer based on mode
*
* @param string $tex LaTeX markup
* @param array $params HTML attributes
* @param int $mode constant indicating rendering mode
* @return MathRenderer appropriate renderer for mode
*/
public static function getRenderer( $tex, $params = array(), $mode = MW_MATH_PNG ) {
global $wgDefaultUserOptions;
$validModes = array( MW_MATH_PNG, MW_MATH_SOURCE, MW_MATH_MATHJAX );
if ( !in_array( $mode, $validModes ) )
$mode = $wgDefaultUserOptions['math'];
switch ( $mode ) {
case MW_MATH_SOURCE:
$renderer = new MathSource( $tex, $params );
break;
case MW_MATH_MATHJAX:
$renderer = new MathMathJax( $tex, $params );
break;
case MW_MATH_PNG:
default:
$renderer = new MathTexvc( $tex, $params );
}
wfDebugLog ( "Math", 'start rendering $' . $renderer->tex . '$' );
return $renderer;
}
/**
* Performs the rendering and returns the rendered element that needs to be embedded.
*
* @return string of rendered HTML
*/
abstract public function render();
/**
* texvc error messages
* TODO: update to MathML
* Returns an internationalized HTML error string
*
* @param string $msg message key for specific error
* @param string $append string to append after error
* @return string HTML error string
*/
protected function getError( $msg, $append = '' ) {
$mf = wfMessage( 'math_failure' )->inContentLanguage()->escaped();
$errmsg = wfMessage( $msg )->inContentLanguage()->escaped();
$source = htmlspecialchars( str_replace( "\n", ' ', $this->tex ) );
return "<strong class='error'>$mf ($errmsg$append): $source</strong>\n";
}
/**
* Return hash of input
*
* @return string hash
*/
public function getInputHash() {
// TODO: What happens if $tex is empty?
$dbr = wfGetDB( DB_SLAVE );
return $dbr->encodeBlob( pack( "H32", md5( $this->tex ) ) ); # Binary packed, not hex
}
/**
* Reads rendering data from database
*
* @return boolean true if read successfully, false otherwise
*/
public function readFromDatabase() {
$dbr = wfGetDB( DB_SLAVE );
$rpage = $dbr->selectRow(
'math',
array(
'math_outputhash', 'math_html_conservativeness', 'math_html',
'math_mathml'
),
array(
'math_inputhash' => $this->getInputHash()
),
__METHOD__
);
if ( $rpage !== false ) {
# Trailing 0x20s can get dropped by the database, add it back on if necessary:
$xhash = unpack( 'H32md5', $dbr->decodeBlob( $rpage->math_outputhash ) . " " );
$this->hash = $xhash['md5'];
$this->conservativeness = $rpage->math_html_conservativeness;
$this->html = $rpage->math_html;
$this->mathml = $rpage->math_mathml;
$this->recall = true;
return true;
}
# Missing from the database and/or the render cache
$this->recall = false;
return false;
}
/**
* Writes rendering entry to database.
*
* WARNING: Use writeCache() instead of this method to be sure that all
* renderer specific (such as squid caching) are taken into account.
* This function stores the values that are currently present in the class to the database even if they are empty.
*
* This function can be seen as protected function.
*/
public function writeToDatabase() {
# Now save it back to the DB:
if ( !wfReadOnly() ) {
$dbw = wfGetDB( DB_MASTER );
if ( $this->hash !== '' ) {
$outmd5_sql = $dbw->encodeBlob( pack( 'H32', $this->hash ) );
} else {
$outmd5_sql = '';
}
wfDebugLog( "Math", 'store entry for $' . $this->tex . '$ in database (hash:' . $this->hash . ')\n' );
$dbw->replace(
'math',
array( 'math_inputhash' ),
array(
'math_inputhash' => $this->getInputHash(),
'math_outputhash' => $outmd5_sql ,
'math_html_conservativeness' => $this->conservativeness,
'math_html' => $this->html,
'math_mathml' => $this->mathml,
),
__METHOD__
);
}
}
/**
* Returns sanitized attributes
*
* @param string $tag element name
* @param array $defaults default attributes
* @param array $overrides attributes to override defaults
* @return array HTML attributes
*/
protected function getAttributes( $tag, $defaults = array(), $overrides = array() ) {
$attribs = Sanitizer::validateTagAttributes( $this->params, $tag );
$attribs = Sanitizer::mergeAttributes( $defaults, $attribs );
$attribs = Sanitizer::mergeAttributes( $attribs, $overrides );
return $attribs;
}
/**
* Writes cache. Does nothing by default
*/
public function writeCache() {
}
/**
* Determines if this is a cached/recalled render
*
* @return boolean true if recalled, false otherwise
*/
public function isRecall() {
return $this->recall;
}
/**
* Gets TeX markup
*
* @return string TeX markup
*/
public function getTex() {
return $this->tex;
}
}