LocalFileRestoreBatch.php

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<?php
use MediaWiki\Deferred\DeferredUpdates;
use MediaWiki\Deferred\SiteStatsUpdate;
use MediaWiki\FileRepo\File\FileSelectQueryBuilder;
use MediaWiki\Language\Language;
use MediaWiki\MediaWikiServices;
use MediaWiki\Status\Status;
use Wikimedia\Rdbms\SelectQueryBuilder;
use Wikimedia\ScopedCallback;
 
class LocalFileRestoreBatch {
    private $file;
 
    private $cleanupBatch;
 
    private $ids;
 
    private $all;
 
    private $unsuppress;
 
    public function __construct( LocalFile $file, $unsuppress = false ) {
        $this->file = $file;
        $this->cleanupBatch = [];
        $this->ids = [];
        $this->unsuppress = $unsuppress;
    }
 
    public function addId( $fa_id ) {
        $this->ids[] = $fa_id;
    }
 
    public function addIds( $ids ) {
        $this->ids = array_merge( $this->ids, $ids );
    }
 
    public function addAll() {
        $this->all = true;
    }
 
    public function execute() {
        global $wgLang;
 
        $repo = $this->file->getRepo();
        if ( !$this->all && !$this->ids ) {
            // Do nothing
            return $repo->newGood();
        }
 
        $status = $this->file->acquireFileLock();
        if ( !$status->isOK() ) {
            return $status;
        }
 
        $dbw = $this->file->repo->getPrimaryDB();
 
        $ownTrx = !$dbw->trxLevel();
        $funcName = __METHOD__;
        $dbw->startAtomic( __METHOD__ );
 
        $unlockScope = new ScopedCallback( function () use ( $dbw, $funcName ) {
            $dbw->endAtomic( $funcName );
            $this->file->releaseFileLock();
        } );
 
        $commentStore = MediaWikiServices::getInstance()->getCommentStore();
 
        $status = $this->file->repo->newGood();
 
        $queryBuilder = $dbw->newSelectQueryBuilder()
            ->select( '1' )
            ->from( 'image' )
            ->where( [ 'img_name' => $this->file->getName() ] );
        // The acquireFileLock() should already prevent changes, but this still may need
        // to bypass any transaction snapshot. However, if we started the
        // trx (which we probably did) then snapshot is post-lock and up-to-date.
        if ( !$ownTrx ) {
            $queryBuilder->lockInShareMode();
        }
        $exists = (bool)$queryBuilder->caller( __METHOD__ )->fetchField();
 
        // Fetch all or selected archived revisions for the file,
        // sorted from the most recent to the oldest.
        $arQueryBuilder = FileSelectQueryBuilder::newForArchivedFile( $dbw );
        $arQueryBuilder->where( [ 'fa_name' => $this->file->getName() ] )
            ->orderBy( 'fa_timestamp', SelectQueryBuilder::SORT_DESC );
 
        if ( !$this->all ) {
            $arQueryBuilder->andWhere( [ 'fa_id' => $this->ids ] );
        }
 
        $result = $arQueryBuilder->caller( __METHOD__ )->fetchResultSet();
 
        $idsPresent = [];
        $storeBatch = [];
        $insertBatch = [];
        $insertCurrent = false;
        $deleteIds = [];
        $first = true;
        $archiveNames = [];
 
        foreach ( $result as $row ) {
            $idsPresent[] = $row->fa_id;
 
            if ( $row->fa_name != $this->file->getName() ) {
                $status->error( 'undelete-filename-mismatch', $wgLang->timeanddate( $row->fa_timestamp ) );
                $status->failCount++;
                continue;
            }
 
            if ( $row->fa_storage_key == '' ) {
                // Revision was missing pre-deletion
                $status->error( 'undelete-bad-store-key', $wgLang->timeanddate( $row->fa_timestamp ) );
                $status->failCount++;
                continue;
            }
 
            $deletedRel = $repo->getDeletedHashPath( $row->fa_storage_key ) .
                $row->fa_storage_key;
            $deletedUrl = $repo->getVirtualUrl() . '/deleted/' . $deletedRel;
 
            if ( isset( $row->fa_sha1 ) ) {
                $sha1 = $row->fa_sha1;
            } else {
                // old row, populate from key
                $sha1 = LocalRepo::getHashFromKey( $row->fa_storage_key );
            }
 
            # Fix leading zero
            if ( strlen( $sha1 ) == 32 && $sha1[0] == '0' ) {
                $sha1 = substr( $sha1, 1 );
            }
 
            if ( $row->fa_major_mime === null || $row->fa_major_mime == 'unknown'
                || $row->fa_minor_mime === null || $row->fa_minor_mime == 'unknown'
                || $row->fa_media_type === null || $row->fa_media_type == 'UNKNOWN'
                || $row->fa_metadata === null
            ) {
                // Refresh our metadata
                // Required for a new current revision; nice for older ones too. :)
                $this->file->loadFromFile( $deletedUrl );
                $mime = $this->file->getMimeType();
                [ $majorMime, $minorMime ] = File::splitMime( $mime );
                $mediaInfo = [
                    'minor_mime' => $minorMime,
                    'major_mime' => $majorMime,
                    'media_type' => $this->file->getMediaType(),
                    'metadata' => $this->file->getMetadataForDb( $dbw )
                ];
            } else {
                $mediaInfo = [
                    'minor_mime' => $row->fa_minor_mime,
                    'major_mime' => $row->fa_major_mime,
                    'media_type' => $row->fa_media_type,
                    'metadata' => $row->fa_metadata
                ];
            }
 
            $comment = $commentStore->getComment( 'fa_description', $row );
            if ( $first && !$exists ) {
                // This revision will be published as the new current version
                $destRel = $this->file->getRel();
                $commentFields = $commentStore->insert( $dbw, 'img_description', $comment );
                $insertCurrent = [
                    'img_name' => $row->fa_name,
                    'img_size' => $row->fa_size,
                    'img_width' => $row->fa_width,
                    'img_height' => $row->fa_height,
                    'img_metadata' => $mediaInfo['metadata'],
                    'img_bits' => $row->fa_bits,
                    'img_media_type' => $mediaInfo['media_type'],
                    'img_major_mime' => $mediaInfo['major_mime'],
                    'img_minor_mime' => $mediaInfo['minor_mime'],
                    'img_actor' => $row->fa_actor,
                    'img_timestamp' => $row->fa_timestamp,
                    'img_sha1' => $sha1
                ] + $commentFields;
 
                // The live (current) version cannot be hidden!
                if ( !$this->unsuppress && $row->fa_deleted ) {
                    $status->fatal( 'undeleterevdel' );
                    return $status;
                }
            } else {
                $archiveName = $row->fa_archive_name;
 
                if ( $archiveName === null ) {
                    // This was originally a current version; we
                    // have to devise a new archive name for it.
                    // Format is <timestamp of archiving>!<name>
                    $timestamp = (int)wfTimestamp( TS_UNIX, $row->fa_deleted_timestamp );
 
                    do {
                        $archiveName = wfTimestamp( TS_MW, $timestamp ) . '!' . $row->fa_name;
                        $timestamp++;
                    } while ( isset( $archiveNames[$archiveName] ) );
                }
 
                $archiveNames[$archiveName] = true;
                $destRel = $this->file->getArchiveRel( $archiveName );
                $insertBatch[] = [
                    'oi_name' => $row->fa_name,
                    'oi_archive_name' => $archiveName,
                    'oi_size' => $row->fa_size,
                    'oi_width' => $row->fa_width,
                    'oi_height' => $row->fa_height,
                    'oi_bits' => $row->fa_bits,
                    'oi_actor' => $row->fa_actor,
                    'oi_timestamp' => $row->fa_timestamp,
                    'oi_metadata' => $mediaInfo['metadata'],
                    'oi_media_type' => $mediaInfo['media_type'],
                    'oi_major_mime' => $mediaInfo['major_mime'],
                    'oi_minor_mime' => $mediaInfo['minor_mime'],
                    'oi_deleted' => $this->unsuppress ? 0 : $row->fa_deleted,
                    'oi_sha1' => $sha1
                ] + $commentStore->insert( $dbw, 'oi_description', $comment );
            }
 
            $deleteIds[] = $row->fa_id;
 
            if ( !$this->unsuppress && $row->fa_deleted & File::DELETED_FILE ) {
                // private files can stay where they are
                $status->successCount++;
            } else {
                $storeBatch[] = [ $deletedUrl, 'public', $destRel ];
                $this->cleanupBatch[] = $row->fa_storage_key;
            }
 
            $first = false;
        }
 
        unset( $result );
 
        // Add a warning to the status object for missing IDs
        $missingIds = array_diff( $this->ids, $idsPresent );
 
        foreach ( $missingIds as $id ) {
            $status->error( 'undelete-missing-filearchive', $id );
        }
 
        if ( !$repo->hasSha1Storage() ) {
            // Remove missing files from batch, so we don't get errors when undeleting them
            $checkStatus = $this->removeNonexistentFiles( $storeBatch );
            if ( !$checkStatus->isGood() ) {
                $status->merge( $checkStatus );
                return $status;
            }
            $storeBatch = $checkStatus->value;
 
            // Run the store batch
            // Use the OVERWRITE_SAME flag to smooth over a common error
            $storeStatus = $this->file->repo->storeBatch( $storeBatch, FileRepo::OVERWRITE_SAME );
            $status->merge( $storeStatus );
 
            if ( !$status->isGood() ) {
                // Even if some files could be copied, fail entirely as that is the
                // easiest thing to do without data loss
                $this->cleanupFailedBatch( $storeStatus, $storeBatch );
                $status->setOK( false );
                return $status;
            }
        }
 
        // Run the DB updates
        // Because we have locked the image row, key conflicts should be rare.
        // If they do occur, we can roll back the transaction at this time with
        // no data loss, but leaving unregistered files scattered throughout the
        // public zone.
        // This is not ideal, which is why it's important to lock the image row.
        if ( $insertCurrent ) {
            $dbw->newInsertQueryBuilder()
                ->insertInto( 'image' )
                ->row( $insertCurrent )
                ->caller( __METHOD__ )->execute();
        }
 
        if ( $insertBatch ) {
            $dbw->newInsertQueryBuilder()
                ->insertInto( 'oldimage' )
                ->rows( $insertBatch )
                ->caller( __METHOD__ )->execute();
        }
 
        if ( $deleteIds ) {
            $dbw->newDeleteQueryBuilder()
                ->deleteFrom( 'filearchive' )
                ->where( [ 'fa_id' => $deleteIds ] )
                ->caller( __METHOD__ )->execute();
        }
 
        // If store batch is empty (all files are missing), deletion is to be considered successful
        if ( $status->successCount > 0 || !$storeBatch || $repo->hasSha1Storage() ) {
            if ( !$exists ) {
                wfDebug( __METHOD__ . " restored {$status->successCount} items, creating a new current" );
 
                DeferredUpdates::addUpdate( SiteStatsUpdate::factory( [ 'images' => 1 ] ) );
 
                $this->file->purgeEverything();
            } else {
                wfDebug( __METHOD__ . " restored {$status->successCount} as archived versions" );
                $this->file->purgeDescription();
            }
        }
 
        ScopedCallback::consume( $unlockScope );
 
        return $status;
    }
 
    protected function removeNonexistentFiles( $triplets ) {
        $files = $filteredTriplets = [];
        foreach ( $triplets as $file ) {
            $files[$file[0]] = $file[0];
        }
 
        $result = $this->file->repo->fileExistsBatch( $files );
        if ( in_array( null, $result, true ) ) {
            return Status::newFatal( 'backend-fail-internal',
                $this->file->repo->getBackend()->getName() );
        }
 
        foreach ( $triplets as $file ) {
            if ( $result[$file[0]] ) {
                $filteredTriplets[] = $file;
            }
        }
 
        return Status::newGood( $filteredTriplets );
    }
 
    protected function removeNonexistentFromCleanup( $batch ) {
        $files = $newBatch = [];
        $repo = $this->file->repo;
 
        foreach ( $batch as $file ) {
            $files[$file] = $repo->getVirtualUrl( 'deleted' ) . '/' .
                rawurlencode( $repo->getDeletedHashPath( $file ) . $file );
        }
 
        $result = $repo->fileExistsBatch( $files );
 
        foreach ( $batch as $file ) {
            if ( $result[$file] ) {
                $newBatch[] = $file;
            }
        }
 
        return $newBatch;
    }
 
    public function cleanup() {
        if ( !$this->cleanupBatch ) {
            return $this->file->repo->newGood();
        }
 
        $this->cleanupBatch = $this->removeNonexistentFromCleanup( $this->cleanupBatch );
 
        $status = $this->file->repo->cleanupDeletedBatch( $this->cleanupBatch );
 
        return $status;
    }
 
    protected function cleanupFailedBatch( $storeStatus, $storeBatch ) {
        $cleanupBatch = [];
 
        foreach ( $storeStatus->success as $i => $success ) {
            // Check if this item of the batch was successfully copied
            if ( $success ) {
                // Item was successfully copied and needs to be removed again
                // Extract ($dstZone, $dstRel) from the batch
                $cleanupBatch[] = [ $storeBatch[$i][1], $storeBatch[$i][2] ];
            }
        }
        $this->file->repo->cleanupBatch( $cleanupBatch );
    }
}