Interwiki.php

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<?php
use \Cdb\Exception as CdbException;
use \Cdb\Reader as CdbReader;

class Interwiki {
    // Cache - removes oldest entry when it hits limit
    protected static $smCache = [];
    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;
        $this->mLocal = (bool)$local;
        $this->mTrans = (bool)$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;
    }

    public static function resetLocalCache() {
        static::$smCache = [];
    }

    public static function invalidateCache( $prefix ) {
        $cache = ObjectCache::getMainWANInstance();
        $key = wfMemcKey( 'interwiki', $prefix );
        $cache->delete( $key );
        unset( static::$smCache[$prefix] );
    }

    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;
            $s->mLocal = (bool)$local;
        } else {
            $s = false;
        }

        return $s;
    }

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

        wfDebug( __METHOD__ . "( $prefix )\n" );
        $value = false;
        try {
            // Resolve site name
            if ( $wgInterwikiScopes >= 3 && !$site ) {
                $site = self::getCacheValue( '__sites:' . wfWikiID() );
                if ( $site == '' ) {
                    $site = $wgInterwikiFallbackSite;
                }
            }

            $value = self::getCacheValue( wfMemcKey( $prefix ) );
            // Site level
            if ( $value == '' && $wgInterwikiScopes >= 3 ) {
                $value = self::getCacheValue( "_{$site}:{$prefix}" );
            }
            // Global Level
            if ( $value == '' && $wgInterwikiScopes >= 2 ) {
                $value = self::getCacheValue( "__global:{$prefix}" );
            }
            if ( $value == 'undef' ) {
                $value = '';
            }
        } catch ( CdbException $e ) {
            wfDebug( __METHOD__ . ": CdbException caught, error message was "
                . $e->getMessage() );
        }

        return $value;
    }

    private static function getCacheValue( $key ) {
        global $wgInterwikiCache;
        static $reader;
        if ( $reader === null ) {
            $reader = is_array( $wgInterwikiCache ) ? false : CdbReader::open( $wgInterwikiCache );
        }
        if ( $reader ) {
            return $reader->get( $key );
        } else {
            return isset( $wgInterwikiCache[$key] ) ? $wgInterwikiCache[$key] : false;
        }
    }

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

        $iwData = [];
        if ( !Hooks::run( 'InterwikiLoadPrefix', [ $prefix, &$iwData ] ) ) {
            return Interwiki::loadFromArray( $iwData );
        }

        if ( is_array( $iwData ) ) {
            $iw = Interwiki::loadFromArray( $iwData );
            if ( $iw ) {
                return $iw; // handled by hook
            }
        }

        $iwData = ObjectCache::getMainWANInstance()->getWithSetCallback(
            wfMemcKey( 'interwiki', $prefix ),
            $wgInterwikiExpiry,
            function ( $oldValue, &$ttl, array &$setOpts ) use ( $prefix ) {
                $dbr = wfGetDB( DB_SLAVE );

                $setOpts += Database::getCacheSetOptions( $dbr );

                $row = $dbr->selectRow(
                    'interwiki',
                    Interwiki::selectFields(),
                    [ 'iw_prefix' => $prefix ],
                    __METHOD__
                );

                return $row ? (array)$row : '!NONEXISTENT';
            }
        );

        if ( is_array( $iwData ) ) {
            return Interwiki::loadFromArray( $iwData ) ?: false;
        }

        return false;
    }

    protected static function loadFromArray( $mc ) {
        if ( isset( $mc['iw_url'] ) ) {
            $iw = new Interwiki();
            $iw->mURL = $mc['iw_url'];
            $iw->mLocal = isset( $mc['iw_local'] ) ? (bool)$mc['iw_local'] : false;
            $iw->mTrans = isset( $mc['iw_trans'] ) ? (bool)$mc['iw_trans'] : false;
            $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 $wgInterwikiScopes, $wgInterwikiFallbackSite;
        static $site;

        wfDebug( __METHOD__ . "()\n" );
        $data = [];
        try {
            /* Resolve site name */
            if ( $wgInterwikiScopes >= 3 && !$site ) {
                $site = self::getCacheValue( '__sites:' . wfWikiID() );

                if ( $site == '' ) {
                    $site = $wgInterwikiFallbackSite;
                }
            }

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

            foreach ( $sources as $source ) {
                $list = self::getCacheValue( '__list:' . $source );
                foreach ( explode( ' ', $list ) as $iw_prefix ) {
                    $row = self::getCacheValue( "{$source}:{$iw_prefix}" );
                    if ( !$row ) {
                        continue;
                    }

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

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

                    $data[$iw_prefix] = [
                        '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 = [];

        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__, [ 'ORDER BY' => 'iw_prefix' ]
        );

        $retval = [];
        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->text();
    }

    public function getDescription() {
        $msg = wfMessage( 'interwiki-desc-' . $this->mPrefix )->inContentLanguage();

        return !$msg->exists() ? '' : $msg->text();
    }

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