ios - replaceItemAtURL : method fails to remove original moved files in some cases

Question

我正在使用 NSFileManager 的 replaceItemAtURL:withItemAtURL:backupItemName:options:resultingItemURL:error: 方法来移动 sqlite 文件，以防使用 replacePersistentStoreAtURL:destinationOptions:withPersistentStoreFromURL 无法移动该文件:sourceOptions:storeType:error: 方法。该文件包含三个组件文件 - 一个以 .sqlite 结尾，一个以 .sqlite-wal 结尾，一个以 .sqlite-shm 结尾。所有文件都使用 replaceItemAtURL:withItemAtURL:backupItemName:options:resultingItemURL:error: 方法正确替换其现有副本；但是，实际上只有移动的 .sqlite 文件从其原始位置删除。 .sqlite-wal 和 .sqlite-shm 文件确实根据需要进行替换，但似乎它们实际上是复制而不是移动，因为这两个原始文件在其成功的 replacePersistentStoreAtURL:destinationOptions 末尾仍然存在。 :withPersistentStoreFromURL:sourceOptions:storeType:error: 操作。一切都发生在同一卷中，因此似乎没有理由制作副本。有人可以帮助我理解为什么会发生这种情况吗？

这是代码。稍后记录的状态消息显示为:

Successfully replaced SQLITE file. SQLITE file does NOT still exist in original location. Successfully replaced WAL file. WAL file DOES still exist in original location. Successfully replaced SHM file. SHM file DOES still exist in original location.

- (void)moveSqliteFileFromMigrateStorePathToFinalStorePathWithCompletionHandler:(void(^)(NSURL * migrateStoreURL,NSString * statusMessage,BOOL actuallyMovedFiles,BOOL movingHudIsRunning))handler {

    __block NSString *statusMessage = nil;
    __block BOOL actuallyMovedFiles = NO;
    __block BOOL hudIsRunning = NO;

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *applicationDocumentsDirectory = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;
    NSString *migrateStorePath = [applicationDocumentsDirectory stringByAppendingPathComponent:@"MyAppData.sqlite"];
    NSURL *migrateStoreURL = [NSURL fileURLWithPath:migrateStorePath];
    NSURL *finalStoreURL = [CoreDataController desiredFinalStoreURL];
    NSString *finalStorePath = finalStoreURL.path;
    NSString *fromWalPath = [migrateStorePath stringByAppendingString:@"-wal"];
    NSString *fromShmPath = [migrateStorePath stringByAppendingString:@"-shm"];
    BOOL walFileExists = [NSFileManager.defaultManager fileExistsAtPath:fromWalPath];
    BOOL shmFileExists = [NSFileManager.defaultManager fileExistsAtPath:fromShmPath];
    BOOL sqliteFileExists = [NSFileManager.defaultManager fileExistsAtPath:migrateStorePath];

    if (sqliteFileExists || shmFileExists || walFileExists) {

        [SVProgressHUD setForegroundColor:CPS_DARK_BLUE_COLOR];
        [SVProgressHUD showWithStatus:NSLocalizedString(@"My App is updating. This one-time operation may take several minutes.",@"")];

        hudIsRunning = YES;

        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

            if (sqliteFileExists) {
                BOOL finalStorePathFileExists = [NSFileManager.defaultManager fileExistsAtPath:finalStorePath];
                NSError * sqliteMoveError = nil;
                BOOL successfulSqliteMove = NO;
                BOOL replacingSqliteFile = NO;
                if (finalStorePathFileExists) {
                    replacingSqliteFile = YES;
                    NSURL *migrateStoreURL = [NSURL fileURLWithPath:migrateStorePath];
                    NSURL *finalStoreURL = [NSURL fileURLWithPath:finalStorePath];
                    successfulSqliteMove = [[NSFileManager defaultManager] replaceItemAtURL:finalStoreURL withItemAtURL:migrateStoreURL backupItemName:@"sqliteBackup" options:NSFileManagerItemReplacementUsingNewMetadataOnly resultingItemURL:nil error:&sqliteMoveError];//NSFileManagerItemReplacementUsingNewMetadataOnly
                }
                else {
                    successfulSqliteMove = [[NSFileManager defaultManager] moveItemAtPath:migrateStorePath toPath:finalStorePath error:&sqliteMoveError];
                }

                if (sqliteMoveError) {
                    DLog(@"The error for the SQLITE move: %@",sqliteMoveError.localizedDescription);
                }

                if (successfulSqliteMove) {
                    actuallyMovedFiles = YES;
                    if([NSFileManager.defaultManager fileExistsAtPath:migrateStorePath]) {
                        statusMessage = replacingSqliteFile?NSLocalizedString(@"Successfully replaced SQLITE file. SQLITE file DOES still exist in original location.", @""):NSLocalizedString(@"Successfully moved SQLITE file. SQLITE file DOES still exist in original location.", @"");
                    }
                    else {
                        statusMessage = replacingSqliteFile?NSLocalizedString(@"Successfully replaced SQLITE file. SQLITE file does NOT still exist in original location.", @""):NSLocalizedString(@"Successfully moved SQLITE file. SQLITE file does NOT still exist in original location.", @"");
                    }
                }
                else {
                    statusMessage = replacingSqliteFile?[NSString stringWithFormat:@"%@ (%@). ",NSLocalizedString(@"Failed to replace SQLITE file", @""),sqliteMoveError.localizedDescription]:[NSString stringWithFormat:@"%@ (%@). ",NSLocalizedString(@"Failed to move SQLITE file", @""),sqliteMoveError.localizedDescription];
                }
            }
            else {
                statusMessage = NSLocalizedString(@"No SQLITE file to move.", @"");
            }

            if (walFileExists) {
                NSString *toWalPath = [finalStorePath stringByAppendingString:@"-wal"];
                BOOL toWalFileExists = [NSFileManager.defaultManager fileExistsAtPath:toWalPath];
                NSError * walMoveError = nil;
                BOOL successfulWalMove = NO;
                BOOL replacingWalFile = NO;
                if (toWalFileExists) {
                    replacingWalFile = YES;
                    NSURL *fromWalURL = [NSURL fileURLWithPath:fromWalPath];
                    NSURL *toWalURL = [NSURL fileURLWithPath:toWalPath];
                    //successfulWalMove = [[NSFileManager defaultManager] replaceItemAtURL:fromWalURL withItemAtURL:toWalURL backupItemName:@"walBackup" options:NSFileManagerItemReplacementUsingNewMetadataOnly resultingItemURL:nil error:&walMoveError];
                    //THE ABOVE CODE WAS WRONG, WHICH WAS WHAT WAS CAUSING THE ISSUE
                    successfulWalMove = [[NSFileManager defaultManager] replaceItemAtURL:toWalURL withItemAtURL:fromWalURL backupItemName:@"walBackup" options:NSFileManagerItemReplacementUsingNewMetadataOnly resultingItemURL:nil error:&walMoveError];
                }
                else {
                    successfulWalMove = [[NSFileManager defaultManager] moveItemAtPath:fromWalPath toPath:toWalPath error:&walMoveError];
                }

                if (walMoveError) {
                    DLog(@"The error for the WAL move: %@",walMoveError.localizedDescription);
                }

                if (successfulWalMove) {
                    actuallyMovedFiles = YES;

                    if([NSFileManager.defaultManager fileExistsAtPath:fromWalPath]) {
                        statusMessage = replacingWalFile?[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully replaced WAL file. WAL file DOES still exist in original location.", @"")]:[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully moved WAL file. WAL file DOES still exist in original location.", @"")];
                    }
                    else {
                        statusMessage = replacingWalFile?[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully replaced WAL file. WAL file does NOT still exist in original location.", @"")]:[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully moved WAL file. WAL file does NOT still exist in original location.", @"")];
                    }
                }
                else {
                    statusMessage = replacingWalFile?[NSString stringWithFormat:@"%@ %@ (%@). ",statusMessage,NSLocalizedString(@"Failed to replace WAL file", @""),walMoveError.localizedDescription]:[NSString stringWithFormat:@"%@ %@ (%@). ",statusMessage,NSLocalizedString(@"Failed to move WAL file", @""),walMoveError.localizedDescription];
                }
            }
            else {
                statusMessage = NSLocalizedString(@"No WAL file to move.", @"");
            }

            if (shmFileExists) {
                NSString *toShmPath = [finalStorePath stringByAppendingString:@"-shm"];
                BOOL toShmFileExists = [NSFileManager.defaultManager fileExistsAtPath:toShmPath];
                NSError * shmMoveError = nil;
                BOOL successfulShmMove = NO;
                BOOL replacingShmFile = NO;
                if (toShmFileExists) {
                    replacingShmFile = YES;
                    NSURL *fromShmURL = [NSURL fileURLWithPath:fromShmPath];
                    NSURL *toShmURL = [NSURL fileURLWithPath:toShmPath];
                    //successfulShmMove = [[NSFileManager defaultManager] replaceItemAtURL:fromShmURL withItemAtURL:toShmURL backupItemName:@"shmBackup" options:NSFileManagerItemReplacementUsingNewMetadataOnly resultingItemURL:nil error:&shmMoveError];
                    //THE ABOVE CODE WAS WRONG, WHICH WAS WHAT WAS CAUSING THE ISSUE
                    successfulShmMove = [[NSFileManager defaultManager] replaceItemAtURL:toShmURL withItemAtURL:fromShmURL backupItemName:@"shmBackup" options:NSFileManagerItemReplacementUsingNewMetadataOnly resultingItemURL:nil error:&shmMoveError];
                }
                else {
                    successfulShmMove = [[NSFileManager defaultManager] moveItemAtPath:fromShmPath toPath:toShmPath error:&shmMoveError];
                }

                if (shmMoveError) {
                    DLog(@"The error for the SHM move: %@",shmMoveError.localizedDescription);
                }

                if (successfulShmMove) {
                    actuallyMovedFiles = YES;

                    if([NSFileManager.defaultManager fileExistsAtPath:fromWalPath]) {
                        statusMessage = replacingShmFile?[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully replaced SHM file. SHM file DOES still exist in original location.", @"")]:[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully moved SHM file. SHM file DOES still exist in original location.", @"")];
                    }
                    else {
                        statusMessage = replacingShmFile?[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully replaced SHM file. SHM file does NOT still exist in original location.", @"")]:[NSString stringWithFormat:@"%@ %@",statusMessage,NSLocalizedString(@"Successfully moved SHM file. SHM file does NOT still exist in original location.", @"")];
                    }
                }
                else {
                    statusMessage = replacingShmFile?[NSString stringWithFormat:@"%@ %@ (%@). ",statusMessage,NSLocalizedString(@"Failed to replace SHM file", @""),shmMoveError.localizedDescription]:[NSString stringWithFormat:@"%@ %@ (%@). ",statusMessage,NSLocalizedString(@"Failed to move SHM file", @""),shmMoveError.localizedDescription];
                }
            }
            else {
                statusMessage = NSLocalizedString(@"No SHM file to move.", @"");
            }

            if (handler) {
                handler(migrateStoreURL,statusMessage,actuallyMovedFiles,hudIsRunning);
            }
        });
    }
    else {
        if (handler) {
            actuallyMovedFiles = NO;
            hudIsRunning = NO;
            statusMessage = NSLocalizedString(@"No SQLITE files to move.", @"");
            handler(migrateStoreURL,statusMessage,actuallyMovedFiles,hudIsRunning);
        }
    }
}

编辑:感谢@matt，问题解决了 - 对于 shm 和 wal 文件，'to' 和 'from' 混淆了。我不敢相信我错过了。所以现在，正如我通过在线研究所期望的那样 - 尽管文档中没有写 - 当替换方法成功时，每个文件实际上都被移动，而不是复制。使用我修改和修复的代码，这是我现在收到的消息:

Successfully replaced SQLITE file. SQLITE file does NOT still exist in original location. Successfully replaced WAL file. WAL file does NOT still exist in original location. Successfully replaced SHM file. SHM file does NOT still exist in original location.

Answer 1

我可能是错的，但乍一看，在我看来，您使用的“从”和“到”概念与我使用它们的方式相反。您可能对将文件从何处移动以及要将其移动到何处感到困惑。