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;

    protected $mURL;

    protected $mAPI;

    protected $mWikiID;

    protected $mLocal;

    protected $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;
    }

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

        return (bool)$result;
    }

    public static 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" );
        $value = false;
        try {
            if ( !$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 = '';
            }
        } catch ( CdbException $e ) {
            wfDebug( __METHOD__ . ": CdbException caught, error message was "
                . $e->getMessage() );
        }

        return $value;
    }

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

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

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

        // is_array is hack for old keys
        if ( $iwData && is_array( $iwData ) ) {
            $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;
        }

        // negative cache hit
        $wgMemc->add( $key, '!NONEXISTENT', $wgInterwikiExpiry );

        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" );
        $data = array();
        try {
            if ( !$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();

            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,
                    );
                }
            }
        } catch ( CdbException $e ) {
            wfDebug( __METHOD__ . ": CdbException caught, error message was "
                . $e->getMessage() );
        }

        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 );
        }

        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'
        );
    }
}