ClassicInterwikiLookup.php

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<?php
namespace MediaWiki\Interwiki;
 
use Interwiki;
use Language;
use MapCacheLRU;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MWException;
use WANObjectCache;
use WikiMap;
use Wikimedia\Rdbms\Database;
use Wikimedia\Rdbms\ILoadBalancer;
 
class ClassicInterwikiLookup implements InterwikiLookup {
 
    private $localCache;
 
    private $contLang;
 
    private $objectCache;
 
    private $objectCacheExpiry;
 
    private $data;
 
    private $interwikiScopes;
 
    private $fallbackSite;
 
    private $thisSite = null;
 
    private $hookRunner;
 
    private $loadBalancer;
 
    public function __construct(
        Language $contLang,
        WANObjectCache $objectCache,
        HookContainer $hookContainer,
        ILoadBalancer $loadBalancer,
        $objectCacheExpiry,
        $interwikiData,
        $interwikiScopes,
        $fallbackSite
    ) {
        $this->localCache = new MapCacheLRU( 1000 );
 
        $this->contLang = $contLang;
        $this->objectCache = $objectCache;
        $this->hookRunner = new HookRunner( $hookContainer );
        $this->loadBalancer = $loadBalancer;
        $this->objectCacheExpiry = $objectCacheExpiry;
        if ( is_array( $interwikiData ) ) {
            $this->data = $interwikiData;
        } elseif ( $interwikiData ) {
            throw new MWException(
                'Setting $wgInterwikiCache to a CDB path is no longer supported' );
        }
        $this->interwikiScopes = $interwikiScopes;
        $this->fallbackSite = $fallbackSite;
    }
 
    public function isValidInterwiki( $prefix ) {
        $result = $this->fetch( $prefix );
 
        return (bool)$result;
    }
 
    public function fetch( $prefix ) {
        if ( $prefix == '' ) {
            return null;
        }
 
        $prefix = $this->contLang->lc( $prefix );
 
        return $this->localCache->getWithSetCallback(
            $prefix,
            function () use ( $prefix ) {
                if ( $this->data !== null ) {
                    $iw = $this->fetchPregenerated( $prefix );
                } else {
                    $iw = $this->load( $prefix );
                    if ( !$iw ) {
                        $iw = false;
                    }
                }
                return $iw;
            }
        );
    }
 
    public function resetLocalCache() {
        $this->localCache->clear();
    }
 
    public function invalidateCache( $prefix ) {
        $this->localCache->clear( $prefix );
 
        $key = $this->objectCache->makeKey( 'interwiki', $prefix );
        $this->objectCache->delete( $key );
    }
 
    private function fetchPregenerated( $prefix ) {
        $value = $this->getPregeneratedEntry( $prefix );
 
        if ( $value ) {
            // Split values
            list( $local, $url ) = explode( ' ', $value, 2 );
            return new Interwiki( $prefix, $url, '', '', (int)$local );
        } else {
            return false;
        }
    }
 
    private function getPregeneratedEntry( $prefix ) {
        wfDebug( __METHOD__ . "( $prefix )" );
 
        $wikiId = WikiMap::getCurrentWikiId();
 
        // Resolve site name
        if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
            $this->thisSite = $this->data['__sites:' . $wikiId] ?? $this->fallbackSite;
        }
 
        $value = $this->data[$wikiId . ':' . $prefix] ?? false;
        // Site level
        if ( $value === false && $this->interwikiScopes >= 3 ) {
            $value = $this->data["_{$this->thisSite}:{$prefix}"] ?? false;
        }
        // Global Level
        if ( $value === false && $this->interwikiScopes >= 2 ) {
            $value = $this->data["__global:{$prefix}"] ?? false;
        }
 
        return $value;
    }
 
    private function load( $prefix ) {
        $iwData = [];
        if ( !$this->hookRunner->onInterwikiLoadPrefix( $prefix, $iwData ) ) {
            return $this->loadFromArray( $iwData );
        }
 
        if ( is_array( $iwData ) ) {
            $iw = $this->loadFromArray( $iwData );
            if ( $iw ) {
                return $iw; // handled by hook
            }
        }
 
        $fname = __METHOD__;
        $iwData = $this->objectCache->getWithSetCallback(
            $this->objectCache->makeKey( 'interwiki', $prefix ),
            $this->objectCacheExpiry,
            function ( $oldValue, &$ttl, array &$setOpts ) use ( $prefix, $fname ) {
                $dbr = $this->loadBalancer->getConnectionRef( DB_REPLICA );
 
                $setOpts += Database::getCacheSetOptions( $dbr );
 
                $row = $dbr->selectRow(
                    'interwiki',
                    self::selectFields(),
                    [ 'iw_prefix' => $prefix ],
                    $fname
                );
 
                return $row ? (array)$row : '!NONEXISTENT';
            }
        );
 
        if ( is_array( $iwData ) ) {
            return $this->loadFromArray( $iwData ) ?: false;
        }
 
        return false;
    }
 
    private function loadFromArray( $mc ) {
        if ( isset( $mc['iw_url'] ) ) {
            $url = $mc['iw_url'];
            $local = $mc['iw_local'] ?? 0;
            $trans = $mc['iw_trans'] ?? 0;
            $api = $mc['iw_api'] ?? '';
            $wikiId = $mc['iw_wikiid'] ?? '';
 
            return new Interwiki( null, $url, $api, $wikiId, $local, $trans );
        }
 
        return false;
    }
 
    private function getAllPrefixesPregenerated( $local ) {
        wfDebug( __METHOD__ . "()" );
 
        $wikiId = WikiMap::getCurrentWikiId();
 
        $data = [];
        /* Resolve site name */
        if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
            $this->thisSite = $this->data['__sites:' . $wikiId] ?? $this->fallbackSite;
        }
 
        // List of interwiki sources
        $sources = [];
        // Global Level
        if ( $this->interwikiScopes >= 2 ) {
            $sources[] = '__global';
        }
        // Site level
        if ( $this->interwikiScopes >= 3 ) {
            $sources[] = '_' . $this->thisSite;
        }
        $sources[] = $wikiId;
 
        foreach ( $sources as $source ) {
            $list = $this->data['__list:' . $source] ?? '';
            foreach ( explode( ' ', $list ) as $iw_prefix ) {
                $row = $this->data["{$source}:{$iw_prefix}"] ?? null;
                if ( !$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,
                ];
            }
        }
 
        return array_values( $data );
    }
 
    public static function buildCdbHash(
        array $allPrefixes, int $scope = 1, ?string $thisSite = null
    ): array {
        $result = [];
        $wikiId = WikiMap::getCurrentWikiId();
        $keyPrefix = ( $scope >= 2 ) ? '__global' : $wikiId;
        if ( $scope >= 3 && $thisSite ) {
            $result[ "__sites:$wikiId" ] = $thisSite;
            $keyPrefix = "_$thisSite";
        }
        $list = [];
        foreach ( $allPrefixes as $iwInfo ) {
            $prefix = $iwInfo['iw_prefix'];
            $result["$keyPrefix:$prefix"] = implode( ' ', [
                $iwInfo['iw_local'] ?? 0, $iwInfo['iw_url']
            ] );
            $list[] = $prefix;
        }
        $result["__list:$keyPrefix"]  = implode( ' ', $list );
        $result["__list:__sites"] = $wikiId;
        return $result;
    }
 
    private function getAllPrefixesDB( $local ) {
        $db = $this->loadBalancer->getConnectionRef( DB_REPLICA );
 
        $where = [];
 
        if ( $local !== null ) {
            $where['iw_local'] = (int)$local;
        }
 
        $res = $db->select( 'interwiki',
            self::selectFields(),
            $where, __METHOD__, [ 'ORDER BY' => 'iw_prefix' ]
        );
 
        $retval = [];
        foreach ( $res as $row ) {
            $retval[] = (array)$row;
        }
 
        return $retval;
    }
 
    public function getAllPrefixes( $local = null ) {
        if ( $this->data !== null ) {
            return $this->getAllPrefixesPregenerated( $local );
        }
 
        return $this->getAllPrefixesDB( $local );
    }
 
    private static function selectFields() {
        return [
            'iw_prefix',
            'iw_url',
            'iw_api',
            'iw_wikiid',
            'iw_local',
            'iw_trans'
        ];
    }
 
}