title.php

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<?php
/**
 * See title.txt
 *
 * @package MediaWiki
 */

/** */
require_once( 'normal/UtfNormal.php' );

define ( 'GAID_FOR_UPDATE', 1 );

# Title::newFromTitle maintains a cache to avoid
# expensive re-normalization of commonly used titles.
# On a batch operation this can become a memory leak
# if not bounded. After hitting this many titles,
# reset the cache.
define( 'MW_TITLECACHE_MAX', 1000 );

/**
 * Title class
 * - Represents a title, which may contain an interwiki designation or namespace
 * - Can fetch various kinds of data from the database, albeit inefficiently.
 *
 * @package MediaWiki
 */
class Title {
	/**
	 * Static cache variables
	 */
	static private $titleCache=array();
	static private $interwikiCache=array();
	
	
	/**
	 * All member variables should be considered private
	 * Please use the accessor functions
	 */

	 /**#@+
	 * @private
	 */

	var $mTextform;           # Text form (spaces not underscores) of the main part
	var $mUrlform;            # URL-encoded form of the main part
	var $mDbkeyform;          # Main part with underscores
	var $mNamespace;          # Namespace index, i.e. one of the NS_xxxx constants
	var $mInterwiki;          # Interwiki prefix (or null string)
	var $mFragment;           # Title fragment (i.e. the bit after the #)
	var $mArticleID;          # Article ID, fetched from the link cache on demand
	var $mLatestID;         # ID of most recent revision
	var $mRestrictions;       # Array of groups allowed to edit this article
	                        # Only null or "sysop" are supported
	var $mRestrictionsLoaded; # Boolean for initialisation on demand
	var $mPrefixedText;       # Text form including namespace/interwiki, initialised on demand
	var $mDefaultNamespace;   # Namespace index when there is no namespace
	                    # Zero except in {{transclusion}} tags
	var $mWatched;      # Is $wgUser watching this page? NULL if unfilled, accessed through userIsWatching()
	/**#@-*/


	/**
	 * Constructor
	 * @private
	 */
	/* private */ function Title() {
		$this->mInterwiki = $this->mUrlform =
		$this->mTextform = $this->mDbkeyform = '';
		$this->mArticleID = -1;
		$this->mNamespace = NS_MAIN;
		$this->mRestrictionsLoaded = false;
		$this->mRestrictions = array();
		# Dont change the following, NS_MAIN is hardcoded in several place
		# See bug #696
		$this->mDefaultNamespace = NS_MAIN;
		$this->mWatched = NULL;
		$this->mLatestID = false;
	}

	/**
	 * Create a new Title from a prefixed DB key
	 * @param string $key The database key, which has underscores
	 *	instead of spaces, possibly including namespace and
	 *	interwiki prefixes
	 * @return Title the new object, or NULL on an error
	 * @static
	 * @access public
	 */
	/* static */ function newFromDBkey( $key ) {
		$t = new Title();
		$t->mDbkeyform = $key;
		if( $t->secureAndSplit() )
			return $t;
		else
			return NULL;
	}

	/**
	 * Create a new Title from text, such as what one would
	 * find in a link. Decodes any HTML entities in the text.
	 *
	 * @param string $text the link text; spaces, prefixes,
	 *	and an initial ':' indicating the main namespace
	 *	are accepted
	 * @param int $defaultNamespace the namespace to use if
	 * 	none is specified by a prefix
	 * @return Title the new object, or NULL on an error
	 * @static
	 * @access public
	 */
	function newFromText( $text, $defaultNamespace = NS_MAIN ) {
		$fname = 'Title::newFromText';

		if( is_object( $text ) ) {
			throw new MWException( 'Title::newFromText given an object' );
		}

		/**
		 * Wiki pages often contain multiple links to the same page.
		 * Title normalization and parsing can become expensive on
		 * pages with many links, so we can save a little time by
		 * caching them.
		 *
		 * In theory these are value objects and won't get changed...
		 */
		if( $defaultNamespace == NS_MAIN && isset( Title::$titleCache[$text] ) ) {
			return Title::$titleCache[$text];
		}

		/**
		 * Convert things like &eacute; &#257; or &#x3017; into real text...
		 */
		$filteredText = Sanitizer::decodeCharReferences( $text );

		$t =& new Title();
		$t->mDbkeyform = str_replace( ' ', '_', $filteredText );
		$t->mDefaultNamespace = $defaultNamespace;

		static $cachedcount = 0 ;
		if( $t->secureAndSplit() ) {
			if( $defaultNamespace == NS_MAIN ) {
				if( $cachedcount >= MW_TITLECACHE_MAX ) {
					# Avoid memory leaks on mass operations...
					Title::$titleCache = array();
					$cachedcount=0;
				}
				$cachedcount++;
				Title::$titleCache[$text] =& $t;
			}
			return $t;
		} else {
			$ret = NULL;
			return $ret;
		}
	}

	/**
	 * Create a new Title from URL-encoded text. Ensures that
	 * the given title's length does not exceed the maximum.
	 * @param string $url the title, as might be taken from a URL
	 * @return Title the new object, or NULL on an error
	 * @static
	 * @access public
	 */
	function newFromURL( $url ) {
		global $wgLegalTitleChars;
		$t = new Title();

		# For compatibility with old buggy URLs. "+" is usually not valid in titles,
		# but some URLs used it as a space replacement and they still come
		# from some external search tools.
		if ( strpos( $wgLegalTitleChars, '+' ) === false ) {
			$url = str_replace( '+', ' ', $url );
		}

		$t->mDbkeyform = str_replace( ' ', '_', $url );
		if( $t->secureAndSplit() ) {
			return $t;
		} else {
			return NULL;
		}
	}

	/**
	 * Create a new Title from an article ID
	 *
	 * @todo This is inefficiently implemented, the page row is requested
	 *       but not used for anything else
	 *
	 * @param int $id the page_id corresponding to the Title to create
	 * @return Title the new object, or NULL on an error
	 * @access public
	 * @static
	 */
	function newFromID( $id ) {
		$fname = 'Title::newFromID';
		$dbr =& wfGetDB( DB_SLAVE );
		$row = $dbr->selectRow( 'page', array( 'page_namespace', 'page_title' ),
			array( 'page_id' => $id ), $fname );
		if ( $row !== false ) {
			$title = Title::makeTitle( $row->page_namespace, $row->page_title );
		} else {
			$title = NULL;
		}
		return $title;
	}

	/**
	 * Make an array of titles from an array of IDs 
	 */
	function newFromIDs( $ids ) {
		$dbr =& wfGetDB( DB_SLAVE );
		$res = $dbr->select( 'page', array( 'page_namespace', 'page_title' ),
			'page_id IN (' . $dbr->makeList( $ids ) . ')', __METHOD__ );

		$titles = array();
		while ( $row = $dbr->fetchObject( $res ) ) {
			$titles[] = Title::makeTitle( $row->page_namespace, $row->page_title );
		}
		return $titles;
	}

	/**
	 * Create a new Title from a namespace index and a DB key.
	 * It's assumed that $ns and $title are *valid*, for instance when
	 * they came directly from the database or a special page name.
	 * For convenience, spaces are converted to underscores so that
	 * eg user_text fields can be used directly.
	 *
	 * @param int $ns the namespace of the article
	 * @param string $title the unprefixed database key form
	 * @return Title the new object
	 * @static
	 * @access public
	 */
	function &makeTitle( $ns, $title ) {
		$t =& new Title();
		$t->mInterwiki = '';
		$t->mFragment = '';
		$t->mNamespace = intval( $ns );
		$t->mDbkeyform = str_replace( ' ', '_', $title );
		$t->mArticleID = ( $ns >= 0 ) ? -1 : 0;
		$t->mUrlform = wfUrlencode( $t->mDbkeyform );
		$t->mTextform = str_replace( '_', ' ', $title );
		return $t;
	}

	/**
	 * Create a new Title frrom a namespace index and a DB key.
	 * The parameters will be checked for validity, which is a bit slower
	 * than makeTitle() but safer for user-provided data.
	 *
	 * @param int $ns the namespace of the article
	 * @param string $title the database key form
	 * @return Title the new object, or NULL on an error
	 * @static
	 * @access public
	 */
	function makeTitleSafe( $ns, $title ) {
		$t = new Title();
		$t->mDbkeyform = Title::makeName( $ns, $title );
		if( $t->secureAndSplit() ) {
			return $t;
		} else {
			return NULL;
		}
 	}

	/**
	 * Create a new Title for the Main Page
	 *
	 * @static
	 * @return Title the new object
	 * @access public
	 */
	function newMainPage() {
		return Title::newFromText( wfMsgForContent( 'mainpage' ) );
	}

	/**
	 * Create a new Title for a redirect
	 * @param string $text the redirect title text
	 * @return Title the new object, or NULL if the text is not a
	 *	valid redirect
	 * @static
	 * @access public
	 */
	function newFromRedirect( $text ) {
		$mwRedir = MagicWord::get( MAG_REDIRECT );
		$rt = NULL;
		if ( $mwRedir->matchStart( $text ) ) {
			if ( preg_match( '/\[{2}(.*?)(?:\||\]{2})/', $text, $m ) ) {
				# categories are escaped using : for example one can enter:
				# #REDIRECT [[:Category:Music]]. Need to remove it.
				if ( substr($m[1],0,1) == ':') {
					# We don't want to keep the ':'
					$m[1] = substr( $m[1], 1 );
				}

				$rt = Title::newFromText( $m[1] );
				# Disallow redirects to Special:Userlogout
				if ( !is_null($rt) && $rt->getNamespace() == NS_SPECIAL && preg_match( '/^Userlogout/i', $rt->getText() ) ) {
					$rt = NULL;
				}
			}
		}
		return $rt;
	}

#----------------------------------------------------------------------------
#	Static functions
#----------------------------------------------------------------------------

	/**
	 * Get the prefixed DB key associated with an ID
	 * @param int $id the page_id of the article
	 * @return Title an object representing the article, or NULL
	 * 	if no such article was found
	 * @static
	 * @access public
	 */
	function nameOf( $id ) {
		$fname = 'Title::nameOf';
		$dbr =& wfGetDB( DB_SLAVE );

		$s = $dbr->selectRow( 'page', array( 'page_namespace','page_title' ),  array( 'page_id' => $id ), $fname );
		if ( $s === false ) { return NULL; }

		$n = Title::makeName( $s->page_namespace, $s->page_title );
		return $n;
	}

	/**
	 * Get a regex character class describing the legal characters in a link
	 * @return string the list of characters, not delimited
	 * @static
	 * @access public
	 */
	function legalChars() {
		global $wgLegalTitleChars;
		return $wgLegalTitleChars;
	}

	/**
	 * Get a string representation of a title suitable for
	 * including in a search index
	 *
	 * @param int $ns a namespace index
	 * @param string $title text-form main part
	 * @return string a stripped-down title string ready for the
	 * 	search index
	 */
	/* static */ function indexTitle( $ns, $title ) {
		global $wgContLang;

		$lc = SearchEngine::legalSearchChars() . '&#;';
		$t = $wgContLang->stripForSearch( $title );
		$t = preg_replace( "/[^{$lc}]+/", ' ', $t );
		$t = strtolower( $t );

		# Handle 's, s'
		$t = preg_replace( "/([{$lc}]+)'s( |$)/", "\\1 \\1's ", $t );
		$t = preg_replace( "/([{$lc}]+)s'( |$)/", "\\1s ", $t );

		$t = preg_replace( "/\\s+/", ' ', $t );

		if ( $ns == NS_IMAGE ) {
			$t = preg_replace( "/ (png|gif|jpg|jpeg|ogg)$/", "", $t );
		}
		return trim( $t );
	}

	/*
	 * Make a prefixed DB key from a DB key and a namespace index
	 * @param int $ns numerical representation of the namespace
	 * @param string $title the DB key form the title
	 * @return string the prefixed form of the title
	 */
	/* static */ function makeName( $ns, $title ) {
		global $wgContLang;

		$n = $wgContLang->getNsText( $ns );
		return $n == '' ? $title : "$n:$title";
	}

	/**
	 * Returns the URL associated with an interwiki prefix
	 * @param string $key the interwiki prefix (e.g. "MeatBall")
	 * @return the associated URL, containing "$1", which should be
	 * 	replaced by an article title
	 * @static (arguably)
	 * @access public
	 */
	function getInterwikiLink( $key )  {
		global $wgMemc, $wgDBname, $wgInterwikiExpiry;
		global $wgInterwikiCache;
		$fname = 'Title::getInterwikiLink';

		$key = strtolower( $key );

		$k = $wgDBname.':interwiki:'.$key;
		if( array_key_exists( $k, Title::$interwikiCache ) ) {
			return Title::$interwikiCache[$k]->iw_url;
		}

		if ($wgInterwikiCache) {
			return Title::getInterwikiCached( $key );
		}

		$s = $wgMemc->get( $k );
		# Ignore old keys with no iw_local
		if( $s && isset( $s->iw_local ) && isset($s->iw_trans)) {
			Title::$interwikiCache[$k] = $s;
			return $s->iw_url;
		}

		$dbr =& wfGetDB( DB_SLAVE );
		$res = $dbr->select( 'interwiki',
			array( 'iw_url', 'iw_local', 'iw_trans' ),
			array( 'iw_prefix' => $key ), $fname );
		if( !$res ) {
			return '';
		}

		$s = $dbr->fetchObject( $res );
		if( !$s ) {
			# Cache non-existence: create a blank object and save it to memcached
			$s = (object)false;
			$s->iw_url = '';
			$s->iw_local = 0;
			$s->iw_trans = 0;
		}
		$wgMemc->set( $k, $s, $wgInterwikiExpiry );
		Title::$interwikiCache[$k] = $s;

		return $s->iw_url;
	}
	
	/**
	 * Fetch interwiki prefix data from local cache in constant database
	 *
	 * More logic is explained in DefaultSettings
	 *
	 * @return string URL of interwiki site
	 * @access public
	 */
	function getInterwikiCached( $key ) {
		global $wgDBname, $wgInterwikiCache, $wgInterwikiScopes, $wgInterwikiFallbackSite;
		static $db, $site;

		if (!$db)
			$db=dba_open($wgInterwikiCache,'r','cdb');
		/* Resolve site name */
		if ($wgInterwikiScopes>=3 and !$site) {
			$site = dba_fetch("__sites:{$wgDBname}", $db);
			if ($site=="")
				$site = $wgInterwikiFallbackSite;
		}
		$value = dba_fetch("{$wgDBname}:{$key}", $db);
		if ($value=='' and $wgInterwikiScopes>=3) {
			/* try site-level */
			$value = dba_fetch("_{$site}:{$key}", $db);