WatchedItemQueryService.php

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<?php

use Wikimedia\Rdbms\IDatabase;
use MediaWiki\Linker\LinkTarget;
use Wikimedia\Assert\Assert;
use Wikimedia\Rdbms\LoadBalancer;

class WatchedItemQueryService {

    const DIR_OLDER = 'older';
    const DIR_NEWER = 'newer';

    const INCLUDE_FLAGS = 'flags';
    const INCLUDE_USER = 'user';
    const INCLUDE_USER_ID = 'userid';
    const INCLUDE_COMMENT = 'comment';
    const INCLUDE_PATROL_INFO = 'patrol';
    const INCLUDE_AUTOPATROL_INFO = 'autopatrol';
    const INCLUDE_SIZES = 'sizes';
    const INCLUDE_LOG_INFO = 'loginfo';
    const INCLUDE_TAGS = 'tags';

    // FILTER_* constants are part of public API (are used in ApiQueryWatchlist and
    // ApiQueryWatchlistRaw classes) and should not be changed.
    // Changing values of those constants will result in a breaking change in the API
    const FILTER_MINOR = 'minor';
    const FILTER_NOT_MINOR = '!minor';
    const FILTER_BOT = 'bot';
    const FILTER_NOT_BOT = '!bot';
    const FILTER_ANON = 'anon';
    const FILTER_NOT_ANON = '!anon';
    const FILTER_PATROLLED = 'patrolled';
    const FILTER_NOT_PATROLLED = '!patrolled';
    const FILTER_AUTOPATROLLED = 'autopatrolled';
    const FILTER_NOT_AUTOPATROLLED = '!autopatrolled';
    const FILTER_UNREAD = 'unread';
    const FILTER_NOT_UNREAD = '!unread';
    const FILTER_CHANGED = 'changed';
    const FILTER_NOT_CHANGED = '!changed';

    const SORT_ASC = 'ASC';
    const SORT_DESC = 'DESC';

    private $loadBalancer;

    private $extensions = null;

    private $commentStore;

    private $actorMigration;

    private $watchedItemStore;

    public function __construct(
        LoadBalancer $loadBalancer,
        CommentStore $commentStore,
        ActorMigration $actorMigration,
        WatchedItemStoreInterface $watchedItemStore
    ) {
        $this->loadBalancer = $loadBalancer;
        $this->commentStore = $commentStore;
        $this->actorMigration = $actorMigration;
        $this->watchedItemStore = $watchedItemStore;
    }

    private function getExtensions() {
        if ( $this->extensions === null ) {
            $this->extensions = [];
            Hooks::run( 'WatchedItemQueryServiceExtensions', [ &$this->extensions, $this ] );
        }
        return $this->extensions;
    }

    private function getConnection() {
        return $this->loadBalancer->getConnectionRef( DB_REPLICA, [ 'watchlist' ] );
    }

    public function getWatchedItemsWithRecentChangeInfo(
        User $user, array $options = [], &$startFrom = null
    ) {
        $options += [
            'includeFields' => [],
            'namespaceIds' => [],
            'filters' => [],
            'allRevisions' => false,
            'usedInGenerator' => false
        ];

        Assert::parameter(
            !isset( $options['rcTypes'] )
                || !array_diff( $options['rcTypes'], [ RC_EDIT, RC_NEW, RC_LOG, RC_EXTERNAL, RC_CATEGORIZE ] ),
            '$options[\'rcTypes\']',
            'must be an array containing only: RC_EDIT, RC_NEW, RC_LOG, RC_EXTERNAL and/or RC_CATEGORIZE'
        );
        Assert::parameter(
            !isset( $options['dir'] ) || in_array( $options['dir'], [ self::DIR_OLDER, self::DIR_NEWER ] ),
            '$options[\'dir\']',
            'must be DIR_OLDER or DIR_NEWER'
        );
        Assert::parameter(
            !isset( $options['start'] ) && !isset( $options['end'] ) && $startFrom === null
                || isset( $options['dir'] ),
            '$options[\'dir\']',
            'must be provided when providing the "start" or "end" options or the $startFrom parameter'
        );
        Assert::parameter(
            !isset( $options['startFrom'] ),
            '$options[\'startFrom\']',
            'must not be provided, use $startFrom instead'
        );
        Assert::parameter(
            !isset( $startFrom ) || ( is_array( $startFrom ) && count( $startFrom ) === 2 ),
            '$startFrom',
            'must be a two-element array'
        );
        if ( array_key_exists( 'watchlistOwner', $options ) ) {
            Assert::parameterType(
                User::class,
                $options['watchlistOwner'],
                '$options[\'watchlistOwner\']'
            );
            Assert::parameter(
                isset( $options['watchlistOwnerToken'] ),
                '$options[\'watchlistOwnerToken\']',
                'must be provided when providing watchlistOwner option'
            );
        }

        $db = $this->getConnection();

        $tables = $this->getWatchedItemsWithRCInfoQueryTables( $options );
        $fields = $this->getWatchedItemsWithRCInfoQueryFields( $options );
        $conds = $this->getWatchedItemsWithRCInfoQueryConds( $db, $user, $options );
        $dbOptions = $this->getWatchedItemsWithRCInfoQueryDbOptions( $options );
        $joinConds = $this->getWatchedItemsWithRCInfoQueryJoinConds( $options );

        if ( $startFrom !== null ) {
            $conds[] = $this->getStartFromConds( $db, $options, $startFrom );
        }

        foreach ( $this->getExtensions() as $extension ) {
            $extension->modifyWatchedItemsWithRCInfoQuery(
                $user, $options, $db,
                $tables,
                $fields,
                $conds,
                $dbOptions,
                $joinConds
            );
        }

        $res = $db->select(
            $tables,
            $fields,
            $conds,
            __METHOD__,
            $dbOptions,
            $joinConds
        );

        $limit = $dbOptions['LIMIT'] ?? INF;
        $items = [];
        $startFrom = null;
        foreach ( $res as $row ) {
            if ( --$limit <= 0 ) {
                $startFrom = [ $row->rc_timestamp, $row->rc_id ];
                break;
            }

            $target = new TitleValue( (int)$row->rc_namespace, $row->rc_title );
            $items[] = [
                new WatchedItem(
                    $user,
                    $target,
                    $this->watchedItemStore->getLatestNotificationTimestamp(
                        $row->wl_notificationtimestamp, $user, $target
                    )
                ),
                $this->getRecentChangeFieldsFromRow( $row )
            ];
        }

        foreach ( $this->getExtensions() as $extension ) {
            $extension->modifyWatchedItemsWithRCInfo( $user, $options, $db, $items, $res, $startFrom );
        }

        return $items;
    }

    public function getWatchedItemsForUser( User $user, array $options = [] ) {
        if ( $user->isAnon() ) {
            // TODO: should this just return an empty array or rather complain loud at this point
            // as e.g. ApiBase::getWatchlistUser does?
            return [];
        }

        $options += [ 'namespaceIds' => [] ];

        Assert::parameter(
            !isset( $options['sort'] ) || in_array( $options['sort'], [ self::SORT_ASC, self::SORT_DESC ] ),
            '$options[\'sort\']',
            'must be SORT_ASC or SORT_DESC'
        );
        Assert::parameter(
            !isset( $options['filter'] ) || in_array(
                $options['filter'], [ self::FILTER_CHANGED, self::FILTER_NOT_CHANGED ]
            ),
            '$options[\'filter\']',
            'must be FILTER_CHANGED or FILTER_NOT_CHANGED'
        );
        Assert::parameter(
            !isset( $options['from'] ) && !isset( $options['until'] ) && !isset( $options['startFrom'] )
            || isset( $options['sort'] ),
            '$options[\'sort\']',
            'must be provided if any of "from", "until", "startFrom" options is provided'
        );

        $db = $this->getConnection();

        $conds = $this->getWatchedItemsForUserQueryConds( $db, $user, $options );
        $dbOptions = $this->getWatchedItemsForUserQueryDbOptions( $options );

        $res = $db->select(
            'watchlist',
            [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
            $conds,
            __METHOD__,
            $dbOptions
        );

        $watchedItems = [];
        foreach ( $res as $row ) {
            $target = new TitleValue( (int)$row->wl_namespace, $row->wl_title );
            // todo these could all be cached at some point?
            $watchedItems[] = new WatchedItem(
                $user,
                $target,
                $this->watchedItemStore->getLatestNotificationTimestamp(
                    $row->wl_notificationtimestamp, $user, $target
                )
            );
        }

        return $watchedItems;
    }

    private function getRecentChangeFieldsFromRow( stdClass $row ) {
        // FIXME: This can be simplified to single array_filter call filtering by key value,
        // now we have stopped supporting PHP 5.5
        $allFields = get_object_vars( $row );
        $rcKeys = array_filter(
            array_keys( $allFields ),
            function ( $key ) {
                return substr( $key, 0, 3 ) === 'rc_';
            }
        );
        return array_intersect_key( $allFields, array_flip( $rcKeys ) );
    }

    private function getWatchedItemsWithRCInfoQueryTables( array $options ) {
        $tables = [ 'recentchanges', 'watchlist' ];
        if ( !$options['allRevisions'] ) {
            $tables[] = 'page';
        }
        if ( in_array( self::INCLUDE_COMMENT, $options['includeFields'] ) ) {
            $tables += $this->commentStore->getJoin( 'rc_comment' )['tables'];
        }
        if ( in_array( self::INCLUDE_USER, $options['includeFields'] ) ||
            in_array( self::INCLUDE_USER_ID, $options['includeFields'] ) ||
            in_array( self::FILTER_ANON, $options['filters'] ) ||
            in_array( self::FILTER_NOT_ANON, $options['filters'] ) ||
            array_key_exists( 'onlyByUser', $options ) || array_key_exists( 'notByUser', $options )
        ) {
            $tables += $this->actorMigration->getJoin( 'rc_user' )['tables'];
        }
        return $tables;
    }

    private function getWatchedItemsWithRCInfoQueryFields( array $options ) {
        $fields = [
            'rc_id',
            'rc_namespace',
            'rc_title',
            'rc_timestamp',
            'rc_type',
            'rc_deleted',
            'wl_notificationtimestamp'
        ];

        $rcIdFields = [
            'rc_cur_id',
            'rc_this_oldid',
            'rc_last_oldid',
        ];
        if ( $options['usedInGenerator'] ) {
            if ( $options['allRevisions'] ) {
                $rcIdFields = [ 'rc_this_oldid' ];
            } else {
                $rcIdFields = [ 'rc_cur_id' ];
            }
        }
        $fields = array_merge( $fields, $rcIdFields );

        if ( in_array( self::INCLUDE_FLAGS, $options['includeFields'] ) ) {
            $fields = array_merge( $fields, [ 'rc_type', 'rc_minor', 'rc_bot' ] );
        }
        if ( in_array( self::INCLUDE_USER, $options['includeFields'] ) ) {
            $fields['rc_user_text'] = $this->actorMigration->getJoin( 'rc_user' )['fields']['rc_user_text'];
        }
        if ( in_array( self::INCLUDE_USER_ID, $options['includeFields'] ) ) {
            $fields['rc_user'] = $this->actorMigration->getJoin( 'rc_user' )['fields']['rc_user'];
        }
        if ( in_array( self::INCLUDE_COMMENT, $options['includeFields'] ) ) {
            $fields += $this->commentStore->getJoin( 'rc_comment' )['fields'];
        }
        if ( in_array( self::INCLUDE_PATROL_INFO, $options['includeFields'] ) ) {
            $fields = array_merge( $fields, [ 'rc_patrolled', 'rc_log_type' ] );
        }
        if ( in_array( self::INCLUDE_SIZES, $options['includeFields'] ) ) {
            $fields = array_merge( $fields, [ 'rc_old_len', 'rc_new_len' ] );
        }
        if ( in_array( self::INCLUDE_LOG_INFO, $options['includeFields'] ) ) {
            $fields = array_merge( $fields, [ 'rc_logid', 'rc_log_type', 'rc_log_action', 'rc_params' ] );
        }
        if ( in_array( self::INCLUDE_TAGS, $options['includeFields'] ) ) {
            // prefixed with rc_ to include the field in getRecentChangeFieldsFromRow
            $fields['rc_tags'] = ChangeTags::makeTagSummarySubquery( 'recentchanges' );
        }

        return $fields;
    }

    private function getWatchedItemsWithRCInfoQueryConds(
        IDatabase $db,
        User $user,
        array $options
    ) {
        $watchlistOwnerId = $this->getWatchlistOwnerId( $user, $options );
        $conds = [ 'wl_user' => $watchlistOwnerId ];

        if ( !$options['allRevisions'] ) {
            $conds[] = $db->makeList(
                [ 'rc_this_oldid=page_latest', 'rc_type=' . RC_LOG ],
                LIST_OR
            );
        }

        if ( $options['namespaceIds'] ) {
            $conds['wl_namespace'] = array_map( 'intval', $options['namespaceIds'] );
        }

        if ( array_key_exists( 'rcTypes', $options ) ) {
            $conds['rc_type'] = array_map( 'intval', $options['rcTypes'] );
        }

        $conds = array_merge(
            $conds,
            $this->getWatchedItemsWithRCInfoQueryFilterConds( $user, $options )
        );

        $conds = array_merge( $conds, $this->getStartEndConds( $db, $options ) );

        if ( !isset( $options['start'] ) && !isset( $options['end'] ) && $db->getType() === 'mysql' ) {
            // This is an index optimization for mysql
            $conds[] = 'rc_timestamp > ' . $db->addQuotes( '' );
        }

        $conds = array_merge( $conds, $this->getUserRelatedConds( $db, $user, $options ) );

        $deletedPageLogCond = $this->getExtraDeletedPageLogEntryRelatedCond( $db, $user );
        if ( $deletedPageLogCond ) {
            $conds[] = $deletedPageLogCond;
        }

        return $conds;
    }

    private function getWatchlistOwnerId( User $user, array $options ) {
        if ( array_key_exists( 'watchlistOwner', $options ) ) {
            $watchlistOwner = $options['watchlistOwner'];
            $ownersToken = $watchlistOwner->getOption( 'watchlisttoken' );
            $token = $options['watchlistOwnerToken'];
            if ( $ownersToken == '' || !hash_equals( $ownersToken, $token ) ) {
                throw ApiUsageException::newWithMessage( null, 'apierror-bad-watchlist-token', 'bad_wltoken' );
            }
            return $watchlistOwner->getId();
        }
        return $user->getId();
    }

    private function getWatchedItemsWithRCInfoQueryFilterConds( User $user, array $options ) {
        $conds = [];

        if ( in_array( self::FILTER_MINOR, $options['filters'] ) ) {
            $conds[] = 'rc_minor != 0';
        } elseif ( in_array( self::FILTER_NOT_MINOR, $options['filters'] ) ) {
            $conds[] = 'rc_minor = 0';
        }

        if ( in_array( self::FILTER_BOT, $options['filters'] ) ) {
            $conds[] = 'rc_bot != 0';
        } elseif ( in_array( self::FILTER_NOT_BOT, $options['filters'] ) ) {
            $conds[] = 'rc_bot = 0';
        }

        if ( in_array( self::FILTER_ANON, $options['filters'] ) ) {
            $conds[] = $this->actorMigration->isAnon(
                $this->actorMigration->getJoin( 'rc_user' )['fields']['rc_user']
            );
        } elseif ( in_array( self::FILTER_NOT_ANON, $options['filters'] ) ) {
            $conds[] = $this->actorMigration->isNotAnon(
                $this->actorMigration->getJoin( 'rc_user' )['fields']['rc_user']
            );
        }

        if ( $user->useRCPatrol() || $user->useNPPatrol() ) {
            // TODO: not sure if this should simply ignore patrolled filters if user does not have the patrol
            // right, or maybe rather fail loud at this point, same as e.g. ApiQueryWatchlist does?
            if ( in_array( self::FILTER_PATROLLED, $options['filters'] ) ) {
                $conds[] = 'rc_patrolled != ' . RecentChange::PRC_UNPATROLLED;
            } elseif ( in_array( self::FILTER_NOT_PATROLLED, $options['filters'] ) ) {
                $conds['rc_patrolled'] = RecentChange::PRC_UNPATROLLED;
            }

            if ( in_array( self::FILTER_AUTOPATROLLED, $options['filters'] ) ) {
                $conds['rc_patrolled'] = RecentChange::PRC_AUTOPATROLLED;
            } elseif ( in_array( self::FILTER_NOT_AUTOPATROLLED, $options['filters'] ) ) {
                $conds[] = 'rc_patrolled != ' . RecentChange::PRC_AUTOPATROLLED;
            }
        }

        if ( in_array( self::FILTER_UNREAD, $options['filters'] ) ) {
            $conds[] = 'rc_timestamp >= wl_notificationtimestamp';
        } elseif ( in_array( self::FILTER_NOT_UNREAD, $options['filters'] ) ) {
            // TODO: should this be changed to use Database::makeList?
            $conds[] = 'wl_notificationtimestamp IS NULL OR rc_timestamp < wl_notificationtimestamp';
        }

        return $conds;
    }

    private function getStartEndConds( IDatabase $db, array $options ) {
        if ( !isset( $options['start'] ) && !isset( $options['end'] ) ) {
            return [];
        }

        $conds = [];

        if ( isset( $options['start'] ) ) {
            $after = $options['dir'] === self::DIR_OLDER ? '<=' : '>=';
            $conds[] = 'rc_timestamp ' . $after . ' ' .
                $db->addQuotes( $db->timestamp( $options['start'] ) );
        }
        if ( isset( $options['end'] ) ) {
            $before = $options['dir'] === self::DIR_OLDER ? '>=' : '<=';
            $conds[] = 'rc_timestamp ' . $before . ' ' .
                $db->addQuotes( $db->timestamp( $options['end'] ) );
        }

        return $conds;
    }

    private function getUserRelatedConds( IDatabase $db, User $user, array $options ) {
        if ( !array_key_exists( 'onlyByUser', $options ) && !array_key_exists( 'notByUser', $options ) ) {
            return [];
        }

        $conds = [];

        if ( array_key_exists( 'onlyByUser', $options ) ) {
            $byUser = User::newFromName( $options['onlyByUser'], false );
            $conds[] = $this->actorMigration->getWhere( $db, 'rc_user', $byUser )['conds'];
        } elseif ( array_key_exists( 'notByUser', $options ) ) {
            $byUser = User::newFromName( $options['notByUser'], false );
            $conds[] = 'NOT(' . $this->actorMigration->getWhere( $db, 'rc_user', $byUser )['conds'] . ')';
        }

        // Avoid brute force searches (T19342)
        $bitmask = 0;
        if ( !$user->isAllowed( 'deletedhistory' ) ) {
            $bitmask = Revision::DELETED_USER;
        } elseif ( !$user->isAllowedAny( 'suppressrevision', 'viewsuppressed' ) ) {
            $bitmask = Revision::DELETED_USER | Revision::DELETED_RESTRICTED;
        }
        if ( $bitmask ) {
            $conds[] = $db->bitAnd( 'rc_deleted', $bitmask ) . " != $bitmask";
        }

        return $conds;
    }

    private function getExtraDeletedPageLogEntryRelatedCond( IDatabase $db, User $user ) {
        // LogPage::DELETED_ACTION hides the affected page, too. So hide those
        // entirely from the watchlist, or someone could guess the title.
        $bitmask = 0;
        if ( !$user->isAllowed( 'deletedhistory' ) ) {
            $bitmask = LogPage::DELETED_ACTION;
        } elseif ( !$user->isAllowedAny( 'suppressrevision', 'viewsuppressed' ) ) {
            $bitmask = LogPage::DELETED_ACTION | LogPage::DELETED_RESTRICTED;
        }
        if ( $bitmask ) {
            return $db->makeList( [
                'rc_type != ' . RC_LOG,
                $db->bitAnd( 'rc_deleted', $bitmask ) . " != $bitmask",
            ], LIST_OR );
        }
        return '';
    }

    private function getStartFromConds( IDatabase $db, array $options, array $startFrom ) {
        $op = $options['dir'] === self::DIR_OLDER ? '<' : '>';
        list( $rcTimestamp, $rcId ) = $startFrom;
        $rcTimestamp = $db->addQuotes( $db->timestamp( $rcTimestamp ) );
        $rcId = (int)$rcId;
        return $db->makeList(
            [
                "rc_timestamp $op $rcTimestamp",
                $db->makeList(
                    [
                        "rc_timestamp = $rcTimestamp",
                        "rc_id $op= $rcId"
                    ],
                    LIST_AND
                )
            ],
            LIST_OR
        );
    }

    private function getWatchedItemsForUserQueryConds( IDatabase $db, User $user, array $options ) {
        $conds = [ 'wl_user' => $user->getId() ];
        if ( $options['namespaceIds'] ) {
            $conds['wl_namespace'] = array_map( 'intval', $options['namespaceIds'] );
        }
        if ( isset( $options['filter'] ) ) {
            $filter = $options['filter'];
            if ( $filter === self::FILTER_CHANGED ) {
                $conds[] = 'wl_notificationtimestamp IS NOT NULL';
            } else {
                $conds[] = 'wl_notificationtimestamp IS NULL';
            }
        }

        if ( isset( $options['from'] ) ) {
            $op = $options['sort'] === self::SORT_ASC ? '>' : '<';
            $conds[] = $this->getFromUntilTargetConds( $db, $options['from'], $op );
        }
        if ( isset( $options['until'] ) ) {
            $op = $options['sort'] === self::SORT_ASC ? '<' : '>';
            $conds[] = $this->getFromUntilTargetConds( $db, $options['until'], $op );
        }
        if ( isset( $options['startFrom'] ) ) {
            $op = $options['sort'] === self::SORT_ASC ? '>' : '<';
            $conds[] = $this->getFromUntilTargetConds( $db, $options['startFrom'], $op );
        }

        return $conds;
    }

    private function getFromUntilTargetConds( IDatabase $db, LinkTarget $target, $op ) {
        return $db->makeList(
            [
                "wl_namespace $op " . $target->getNamespace(),
                $db->makeList(
                    [
                        'wl_namespace = ' . $target->getNamespace(),
                        "wl_title $op= " . $db->addQuotes( $target->getDBkey() )
                    ],
                    LIST_AND
                )
            ],
            LIST_OR
        );
    }

    private function getWatchedItemsWithRCInfoQueryDbOptions( array $options ) {
        $dbOptions = [];

        if ( array_key_exists( 'dir', $options ) ) {
            $sort = $options['dir'] === self::DIR_OLDER ? ' DESC' : '';
            $dbOptions['ORDER BY'] = [ 'rc_timestamp' . $sort, 'rc_id' . $sort ];
        }

        if ( array_key_exists( 'limit', $options ) ) {
            $dbOptions['LIMIT'] = (int)$options['limit'] + 1;
        }

        return $dbOptions;
    }

    private function getWatchedItemsForUserQueryDbOptions( array $options ) {
        $dbOptions = [];
        if ( array_key_exists( 'sort', $options ) ) {
            $dbOptions['ORDER BY'] = [
                "wl_namespace {$options['sort']}",
                "wl_title {$options['sort']}"
            ];
            if ( count( $options['namespaceIds'] ) === 1 ) {
                $dbOptions['ORDER BY'] = "wl_title {$options['sort']}";
            }
        }
        if ( array_key_exists( 'limit', $options ) ) {
            $dbOptions['LIMIT'] = (int)$options['limit'];
        }
        return $dbOptions;
    }

    private function getWatchedItemsWithRCInfoQueryJoinConds( array $options ) {
        $joinConds = [
            'watchlist' => [ 'JOIN',
                [
                    'wl_namespace=rc_namespace',
                    'wl_title=rc_title'
                ]
            ]
        ];
        if ( !$options['allRevisions'] ) {
            $joinConds['page'] = [ 'LEFT JOIN', 'rc_cur_id=page_id' ];
        }
        if ( in_array( self::INCLUDE_COMMENT, $options['includeFields'] ) ) {
            $joinConds += $this->commentStore->getJoin( 'rc_comment' )['joins'];
        }
        if ( in_array( self::INCLUDE_USER, $options['includeFields'] ) ||
            in_array( self::INCLUDE_USER_ID, $options['includeFields'] ) ||
            in_array( self::FILTER_ANON, $options['filters'] ) ||
            in_array( self::FILTER_NOT_ANON, $options['filters'] ) ||
            array_key_exists( 'onlyByUser', $options ) || array_key_exists( 'notByUser', $options )
        ) {
            $joinConds += $this->actorMigration->getJoin( 'rc_user' )['joins'];
        }
        return $joinConds;
    }

}