MagicWord.php

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<?php

# This class encapsulates "magic words" such as #redirect, __NOTOC__, etc.
# Usage:
#     if (MagicWord::get( MAG_REDIRECT )->match( $text ) )
# 
# Possible future improvements: 
#   * Simultaneous searching for a number of magic words
#   * $wgMagicWords in shared memory
#
# Please avoid reading the data out of one of these objects and then writing 
# special case code. If possible, add another match()-like function here.

/*private*/ $wgMagicFound = false;

define("MAG_REDIRECT", 0);
define("MAG_NOTOC", 1);
define("MAG_START", 2);
define("MAG_CURRENTMONTH", 3);
define("MAG_CURRENTMONTHNAME", 4);
define("MAG_CURRENTDAY", 5);
define("MAG_CURRENTDAYNAME", 6);
define("MAG_CURRENTYEAR", 7);
define("MAG_CURRENTTIME", 8);
define("MAG_NUMBEROFARTICLES", 9);
define("MAG_CURRENTMONTHNAMEGEN", 10);
define("MAG_MSG", 11);
define("MAG_SUBST", 12);
define("MAG_MSGNW", 13);
define("MAG_NOEDITSECTION", 14);
define("MAG_END", 15);
define("MAG_IMG_THUMBNAIL",  16);
define("MAG_IMG_RIGHT",      17);
define("MAG_IMG_LEFT",       18);
define("MAG_IMG_NONE",       19);
define("MAG_IMG_WIDTH",      20);
define("MAG_IMG_CENTER",      21);
define("MAG_INT", 22);
define("MAG_FORCETOC", 23);
define("MAG_SITENAME", 24);
define("MAG_NS", 25);
define("MAG_LOCALURL", 26);
define("MAG_LOCALURLE", 27);
define("MAG_SERVER", 28);
define("MAG_IMG_FRAMED", 29);
define("MAG_PAGENAME", 30);
define("MAG_NAMESPACE", 31);

$wgVariableIDs = array(
        MAG_CURRENTMONTH,
        MAG_CURRENTMONTHNAME,
        MAG_CURRENTDAY,
        MAG_CURRENTDAYNAME,
        MAG_CURRENTYEAR,
        MAG_CURRENTTIME,
        MAG_NUMBEROFARTICLES,
        MAG_CURRENTMONTHNAMEGEN,
    MAG_SITENAME,
        MAG_SERVER,
        MAG_PAGENAME,
        MAG_NAMESPACE
);

class MagicWord {
        /*private*/ var $mId, $mSynonyms, $mCaseSensitive, $mRegex;
        /*private*/ var $mRegexStart, $mBaseRegex, $mVariableRegex;
        /*private*/ var $mModified;     

        function MagicWord($id = 0, $syn = "", $cs = false) 
        {
                $this->mId = $id;
                $this->mSynonyms = (array)$syn;
                $this->mCaseSensitive = $cs;
                $this->mRegex = "";
                $this->mRegexStart = "";
                $this->mVariableRegex = "";
                $this->mVariableStartToEndRegex = "";
                $this->mModified = false;
        }

        # Factory: creates an object representing an ID
        /*static*/ function &get( $id )
        {
                global $wgMagicWords;
                
                if (!array_key_exists( $id, $wgMagicWords ) ) {
                        $mw = new MagicWord();
                        $mw->load( $id );
                        $wgMagicWords[$id] = $mw;
                }
                return $wgMagicWords[$id];
        }
        
        # Initialises this object with an ID
        function load( $id )
        {
                global $wgLang;         
                $this->mId = $id;
                $wgLang->getMagic( $this );
        }
        
        # Preliminary initialisation
        /* private */ function initRegex()
        {
                $variableClass = Title::legalChars();
                $escSyn = array_map( "preg_quote", $this->mSynonyms );
                $this->mBaseRegex = implode( "|", $escSyn );
                $case = $this->mCaseSensitive ? "" : "i";
                $this->mRegex = "/{$this->mBaseRegex}/{$case}";
                $this->mRegexStart = "/^{$this->mBaseRegex}/{$case}";
                $this->mVariableRegex = str_replace( "\\$1", "([$variableClass]*?)", $this->mRegex );
                $this->mVariableStartToEndRegex = str_replace( "\\$1", "([$variableClass]*?)", 
                        "/^({$this->mBaseRegex})$/{$case}" );
        }
        
        # Gets a regex representing matching the word
        function getRegex()
        {
                if ($this->mRegex == "" ) {
                        $this->initRegex();
                }
                return $this->mRegex;
        }

        # Gets a regex matching the word, if it is at the 
        # string start
        function getRegexStart()
        {
                if ($this->mRegex == "" ) {
                        $this->initRegex();
                }
                return $this->mRegexStart;
        }

        # regex without the slashes and what not
        function getBaseRegex()
        {
                if ($this->mRegex == "") {
                        $this->initRegex();
                }
                return $this->mBaseRegex;
        }
                
        # Returns true if the text contains the word
        function match( $text ) {
                return preg_match( $this->getRegex(), $text );
        }

        # Returns true if the text starts with the word
        function matchStart( $text ) 
        {
                return preg_match( $this->getRegexStart(), $text );
        }

        # Returns NULL if there's no match, the value of $1 otherwise
        # The return code is the matched string, if there's no variable
        # part in the regex and the matched variable part ($1) if there
        # is one.
        function matchVariableStartToEnd( $text ) {
                $matchcount = preg_match( $this->getVariableStartToEndRegex(), $text, $matches );
                if ( $matchcount == 0 ) {
                        return NULL;
                } elseif ( count($matches) == 1 ) {
                        return $matches[0];
                } else {
                        return $matches[1];
                }
        }


        # Returns true if the text matches the word, and alters the
        # input string, removing all instances of the word
        function matchAndRemove( &$text )
        {
                global $wgMagicFound;
                $wgMagicFound = false;
                $text = preg_replace_callback( $this->getRegex(), "pregRemoveAndRecord", $text );
                return $wgMagicFound;
        }

        function matchStartAndRemove( &$text ) {
                global $wgMagicFound;
                $wgMagicFound = false;
                $text = preg_replace_callback( $this->getRegexStart(), "pregRemoveAndRecord", $text );
                return $wgMagicFound;
        }               


        # Replaces the word with something else
        function replace( $replacement, $subject )
        {
                $res = preg_replace( $this->getRegex(), $replacement, $subject );
                $this->mModified = !($res === $subject);
                return $res;
        }

        # Variable handling: {{SUBST:xxx}} style words
        # Calls back a function to determine what to replace xxx with
        # Input word must contain $1
        function substituteCallback( $text, $callback ) {
                $regex = $this->getVariableRegex();
                $res = preg_replace_callback( $this->getVariableRegex(), $callback, $text );
                $this->mModified = !($res === $text);
                return $res;
        }

        # Matches the word, where $1 is a wildcard
        function getVariableRegex()
        {
                if ( $this->mVariableRegex == "" ) {
                        $this->initRegex();
                } 
                return $this->mVariableRegex;
        }

        # Matches the entire string, where $1 is a wildcard
        function getVariableStartToEndRegex()
        {
                if ( $this->mVariableStartToEndRegex == "" ) {
                        $this->initRegex();
                } 
                return $this->mVariableStartToEndRegex;
        }

        # Accesses the synonym list directly
        function getSynonym( $i ) {
                return $this->mSynonyms[$i];
        }

        # Returns true if the last call to replace() or substituteCallback() 
        # returned a modified text, otherwise false.
        function getWasModified(){
                return $this->mModified;
        }

        # $magicarr is an associative array of (magic word ID => replacement)
        # This method uses the php feature to do several replacements at the same time,
        # thereby gaining some efficiency. The result is placed in the out variable
        # $result. The return value is true if something was replaced.

        /* static */ function replaceMultiple( $magicarr, $subject, &$result ){
                $search = array();
                $replace = array();
                foreach( $magicarr as $id => $replacement ){
                        $mw = MagicWord::get( $id );
                        $search[] = $mw->getRegex();
                        $replace[] = $replacement;
                }

                $result = preg_replace( $search, $replace, $subject );
                return !($result === $subject);
        }

        # Adds all the synonyms of this MagicWord to an array, to allow quick lookup in a list of magic words
        function addToArray( &$array, $value ) 
        {
                foreach ( $this->mSynonyms as $syn ) {
                        $array[$syn] = $value;
                }
        }
}

# Used in matchAndRemove()
/*private*/ function pregRemoveAndRecord( $match )
{
        global $wgMagicFound;
        $wgMagicFound = true;
        return "";
}

?>

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