WatchedCondition.php

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<?php
 
namespace MediaWiki\RecentChanges\ChangesListQuery;
 
use MediaWiki\User\UserIdentity;
use MediaWiki\Utils\MWTimestamp;
use stdClass;
use Wikimedia\Rdbms\IReadableDatabase;
use Wikimedia\Rdbms\RawSQLExpression;
use Wikimedia\Timestamp\TimestampFormat as TS;
 
class WatchedCondition extends ChangesListConditionBase {
    private ?int $userId = null;
 
    private const ALL_VALUES = [ 'notwatched', 'watchedold', 'watchednew' ];
 
    public function __construct( private bool $enableExpiry ) {
    }
 
    public function setUser( UserIdentity $user ) {
        $this->userId = $user->getId();
    }
 
    public function validateValue( $value ) {
        if ( !in_array( $value, self::ALL_VALUES, true ) ) {
            throw new \InvalidArgumentException( 'unknown value for watched filter' );
        }
        return $value;
    }
 
    public function evaluate( stdClass $row, $value ): bool {
        if ( !$this->userId
            || ( $this->enableExpiry && $row->we_expiry !== null
                && MWTimestamp::convert( TS::UNIX, $row->we_expiry ) <= wfTimestamp() )
            || $row->wl_user === null
        ) {
            return $value === 'notwatched';
        } elseif ( $row->rc_timestamp &&
            $row->wl_notificationtimestamp &&
            $row->rc_timestamp >= $row->wl_notificationtimestamp
        ) {
            return $value === 'watchednew';
        } else {
            return $value === 'watchedold';
        }
    }
 
    protected function prepareCapture( IReadableDatabase $dbr, QueryBackend $query ) {
        if ( !$this->userId ) {
            return;
        }
        $query->joinForFields( 'watchlist' )->weakLeft();
        $query->fields( [ 'wl_user', 'wl_notificationtimestamp', 'rc_timestamp' ] );
        if ( $this->enableExpiry ) {
            $query->joinForFields( 'watchlist_expiry' )->left();
            $query->fields( 'we_expiry' );
        }
    }
 
    protected function prepareConds( IReadableDatabase $dbr, QueryBackend $query ) {
        $set = $this->getEnumValues( self::ALL_VALUES );
        if ( $set === null ) {
            return;
        } elseif ( $set === [] ) {
            $query->forceEmptySet();
            return;
        }
        $notwatched = in_array( 'notwatched', $set, true );
        $watchedold = in_array( 'watchedold', $set, true );
        $watchednew = in_array( 'watchednew', $set, true );
 
        if ( !$this->userId ) {
            if ( !$notwatched ) {
                $query->forceEmptySet();
            }
            return;
        }
 
        $orConds = [];
        if ( $notwatched ) {
            // Permit not watched: left join, allow join failure or expired
            $query->joinForConds( 'watchlist' )->left();
            $orConds[] = $dbr->expr( 'wl_user', '=', null );
            if ( $this->enableExpiry ) {
                $query->joinForConds( 'watchlist_expiry' )->left();
                $orConds[] = $dbr->expr( 'we_expiry', '<=', $dbr->timestamp() );
            }
        } else {
            // Require watched: reorderable join, do not allow expired
            $query->adjustDensity( QueryBackend::DENSITY_WATCHLIST )
                ->joinOrderHint( QueryBackend::JOIN_ORDER_OTHER );
            $query->joinForConds( 'watchlist' )->reorderable();
            if ( $this->enableExpiry ) {
                $query->joinForConds( 'watchlist_expiry' )->left();
                $query->where(
                    $dbr->expr( 'we_expiry', '=', null )
                        ->or( 'we_expiry', '>', $dbr->timestamp() )
                );
            }
        }
 
        if ( $watchedold xor $watchednew ) {
            if ( $watchedold ) {
                $oldExpr = ( new RawSQLExpression( 'rc_timestamp < wl_notificationtimestamp' ) )
                    ->or( 'wl_notificationtimestamp', '=', null );
            } else {
                $oldExpr = new RawSQLExpression( 'rc_timestamp >= wl_notificationtimestamp' );
            }
            if ( $notwatched ) {
                // Technically redundant since comparison with null wl_notificationtimestamp
                // is always false
                $oldExpr = $dbr->expr( 'wl_user', '!=', null )->andExpr( $oldExpr );
            }
            $orConds[] = $oldExpr;
        }
 
        if ( count( $orConds ) === 1 ) {
            $query->where( $orConds[0] );
        } elseif ( count( $orConds ) ) {
            $query->where( $dbr->orExpr( $orConds ) );
        }
    }
}