Interwiki.php

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<?php
class Interwiki {

        // Cache - removes oldest entry when it hits limit
        protected static $smCache = array();
        const CACHE_LIMIT = 100; // 0 means unlimited, any other value is max number of entries.

        protected $mPrefix, $mURL, $mAPI, $mWikiID, $mLocal, $mTrans;

        public function __construct( $prefix = null, $url = '', $api = '', $wikiId = '', $local = 0, $trans = 0 ) {
                $this->mPrefix = $prefix;
                $this->mURL = $url;
                $this->mAPI = $api;
                $this->mWikiID = $wikiId;
                $this->mLocal = $local;
                $this->mTrans = $trans;
        }

        static public function isValidInterwiki( $prefix ) {
                $result = self::fetch( $prefix );
                return (bool)$result;
        }

        static public function fetch( $prefix ) {
                global $wgContLang;
                if( $prefix == '' ) {
                        return null;
                }
                $prefix = $wgContLang->lc( $prefix );
                if( isset( self::$smCache[$prefix] ) ) {
                        return self::$smCache[$prefix];
                }
                global $wgInterwikiCache;
                if( $wgInterwikiCache ) {
                        $iw = Interwiki::getInterwikiCached( $prefix );
                } else {
                        $iw = Interwiki::load( $prefix );
                        if( !$iw ) {
                                $iw = false;
                        }
                }
                if( self::CACHE_LIMIT && count( self::$smCache ) >= self::CACHE_LIMIT ) {
                        reset( self::$smCache );
                        unset( self::$smCache[key( self::$smCache )] );
                }
                self::$smCache[$prefix] = $iw;
                return $iw;
        }

        protected static function getInterwikiCached( $prefix ) {
                $value = self::getInterwikiCacheEntry( $prefix );

                $s = new Interwiki( $prefix );
                if ( $value != '' ) {
                        // Split values
                        list( $local, $url ) = explode( ' ', $value, 2 );
                        $s->mURL = $url;
                        $s->mLocal = (int)$local;
                } else {
                        $s = false;
                }
                return $s;
        }

        protected static function getInterwikiCacheEntry( $prefix ) {
                global $wgInterwikiCache, $wgInterwikiScopes, $wgInterwikiFallbackSite;
                static $db, $site;

                wfDebug( __METHOD__ . "( $prefix )\n" );
                if( !$db ) {
                        $db = CdbReader::open( $wgInterwikiCache );
                }
                /* Resolve site name */
                if( $wgInterwikiScopes >= 3 && !$site ) {
                        $site = $db->get( '__sites:' . wfWikiID() );
                        if ( $site == '' ) {
                                $site = $wgInterwikiFallbackSite;
                        }
                }

                $value = $db->get( wfMemcKey( $prefix ) );
                // Site level
                if ( $value == '' && $wgInterwikiScopes >= 3 ) {
                        $value = $db->get( "_{$site}:{$prefix}" );
                }
                // Global Level
                if ( $value == '' && $wgInterwikiScopes >= 2 ) {
                        $value = $db->get( "__global:{$prefix}" );
                }
                if ( $value == 'undef' ) {
                        $value = '';
                }


                return $value;
        }

        protected static function load( $prefix ) {
                global $wgMemc, $wgInterwikiExpiry;

                $iwData = false;
                if ( !wfRunHooks( 'InterwikiLoadPrefix', array( $prefix, &$iwData ) ) ) {
                        return Interwiki::loadFromArray( $iwData );
                }

                if ( !$iwData ) {
                        $key = wfMemcKey( 'interwiki', $prefix );
                        $iwData = $wgMemc->get( $key );
                        if ( $iwData === '!NONEXISTENT' ) {
                                return false; // negative cache hit
                        }
                }

                if( $iwData && is_array( $iwData ) ) { // is_array is hack for old keys
                        $iw = Interwiki::loadFromArray( $iwData );
                        if( $iw ) {
                                return $iw;
                        }
                }

                $db = wfGetDB( DB_SLAVE );

                $row = $db->fetchRow( $db->select( 'interwiki', self::selectFields(), array( 'iw_prefix' => $prefix ),
                        __METHOD__ ) );
                $iw = Interwiki::loadFromArray( $row );
                if ( $iw ) {
                        $mc = array(
                                'iw_url' => $iw->mURL,
                                'iw_api' => $iw->mAPI,
                                'iw_local' => $iw->mLocal,
                                'iw_trans' => $iw->mTrans
                        );
                        $wgMemc->add( $key, $mc, $wgInterwikiExpiry );
                        return $iw;
                } else {
                        $wgMemc->add( $key, '!NONEXISTENT', $wgInterwikiExpiry ); // negative cache hit
                }

                return false;
        }

        protected static function loadFromArray( $mc ) {
                if( isset( $mc['iw_url'] ) ) {
                        $iw = new Interwiki();
                        $iw->mURL = $mc['iw_url'];
                        $iw->mLocal = isset( $mc['iw_local'] ) ? $mc['iw_local'] : 0;
                        $iw->mTrans = isset( $mc['iw_trans'] ) ? $mc['iw_trans'] : 0;
                        $iw->mAPI = isset( $mc['iw_api'] ) ? $mc['iw_api'] : '';
                        $iw->mWikiID = isset( $mc['iw_wikiid'] ) ? $mc['iw_wikiid'] : '';

                        return $iw;
                }
                return false;
        }

        protected static function getAllPrefixesCached( $local ) {
                global $wgInterwikiCache, $wgInterwikiScopes, $wgInterwikiFallbackSite;
                static $db, $site;

                wfDebug( __METHOD__ . "()\n" );
                if( !$db ) {
                        $db = CdbReader::open( $wgInterwikiCache );
                }
                /* Resolve site name */
                if( $wgInterwikiScopes >= 3 && !$site ) {
                        $site = $db->get( '__sites:' . wfWikiID() );
                        if ( $site == '' ) {
                                $site = $wgInterwikiFallbackSite;
                        }
                }

                // List of interwiki sources
                $sources = array();
                // Global Level
                if ( $wgInterwikiScopes >= 2 ) {
                        $sources[] = '__global';
                }
                // Site level
                if ( $wgInterwikiScopes >= 3 ) {
                        $sources[] = '_' . $site;
                }
                $sources[] = wfWikiID();

                $data = array();

                foreach( $sources as $source ) {
                        $list = $db->get( "__list:{$source}" );
                        foreach ( explode( ' ', $list ) as $iw_prefix ) {
                                $row = $db->get( "{$source}:{$iw_prefix}" );
                                if( !$row ) {
                                        continue;
                                }

                                list( $iw_local, $iw_url ) = explode( ' ', $row );

                                if ( $local !== null && $local != $iw_local ) {
                                        continue;
                                }

                                $data[$iw_prefix] = array(
                                        'iw_prefix' => $iw_prefix,
                                        'iw_url'    => $iw_url,
                                        'iw_local'  => $iw_local,
                                );
                        }
                }

                ksort( $data );

                return array_values( $data );
        }

        protected static function getAllPrefixesDB( $local ) {
                $db = wfGetDB( DB_SLAVE );

                $where = array();

                if ( $local !== null ) {
                        if ( $local == 1 ) {
                                $where['iw_local'] = 1;
                        } elseif ( $local == 0 ) {
                                $where['iw_local'] = 0;
                        }
                }

                $res = $db->select( 'interwiki',
                        self::selectFields(),
                        $where, __METHOD__, array( 'ORDER BY' => 'iw_prefix' )
                );
                $retval = array();
                foreach ( $res as $row ) {
                        $retval[] = (array)$row;
                }
                return $retval;
        }

        public static function getAllPrefixes( $local = null ) {
                global $wgInterwikiCache;

                if ( $wgInterwikiCache ) {
                        return self::getAllPrefixesCached( $local );
                } else {
                        return self::getAllPrefixesDB( $local );
                }
        }

        public function getURL( $title = null ) {
                $url = $this->mURL;
                if( $title !== null ) {
                        $url = str_replace( "$1", wfUrlencode( $title ), $url );
                }
                return $url;
        }

        public function getAPI() {
                return $this->mAPI;
        }

        public function getWikiID() {
                return $this->mWikiID;
        }

        public function isLocal() {
                return $this->mLocal;
        }

        public function isTranscludable() {
                return $this->mTrans;
        }

        public function getName() {
                $msg = wfMessage( 'interwiki-name-' . $this->mPrefix )->inContentLanguage();
                return !$msg->exists() ? '' : $msg;
        }

        public function getDescription() {
                $msg = wfMessage( 'interwiki-desc-' . $this->mPrefix )->inContentLanguage();
                return !$msg->exists() ? '' : $msg;
        }

        public static function selectFields() {
                return array(
                        'iw_prefix',
                        'iw_url',
                        'iw_api',
                        'iw_wikiid',
                        'iw_local',
                        'iw_trans'
                );
        }
}